RNA molecules for modulating flowering in plants

Abstract

The present invention relates to new double stranded RNA (dsRNA) structures and their use in modulating flowering in plants. The present invention also relates to methods of modulating the time of plant flowering.

Description

RNA MOLECULES FOR MODULATING FLOWERING IN PLANTS FIELD OF THE INVENTION The present invention relates to new double stranded RNA (dsRNA) structures and their use in modulating flowering in plants. The present invention also relates to methods of modulating the time of plant flowering. BACKGROUND OF THE INVENTION RNA silencing is an evolutionarily conserved gene silencing mechanism in eukaryotes that is induced by double-stranded RNA (dsRNA) which may be of a form designated hairpin structured RNA (hpRNA). In the basic RNA silencing pathway, dsRNA is processed by Dicer proteins into short, 20-25 nucleotide (nt) small RNA duplexes, of which one strand is bound to Argonaute (AGO) proteins to form an RNA- induced silencing complex (RISC). This silencing complex uses the small RNA as a guide to find and bind to complementary single-stranded RNA, where the AGO protein cleaves the RNA resulting in its degradation. In plants, multiple RNA silencing pathways exist, including microRNA (miRNA), trans-acting small interfering RNA (tasiRNA), repeat-associated siRNA (rasiRNA) and exogenic (virus and transgene) siRNA (exosiRNA) pathways. miRNAs are 20-24 nt small RNAs processed in the nucleus by Dicer-like 1 (DCL1) from short stem-loop precursor RNAs that are transcribed by RNA polymerase II from MIR genes. tasiRNAs are phased siRNAs of primarily 21 nt in size derived from DCL4 processing of long dsRNA synthesized by RNA-dependent RNA polymerase 6 (RDR6) from miRNA-cleaved TAS RNA fragment. The 24-nt rasiRNAs are processed by DCL3, and the precursor dsRNA is generated by the combined function of plant-specific DNA- dependent RNA polymerase IV (PollV) and RDR2 from repetitive DNA in the genome. The exosiRNA pathway overlaps with the tasiRNA and rasiRNA pathways and both DCL4 and DCL3 are involved in exosiRNA processing. In addition to DCL1, DCL3 and DCLA4, the model plant Arabidopsis thaliana and other higher plants encodes DCL2 or equivalent, which generates 22-nt siRNAs including 22-nt exosiRNAs, and plays a key role in systemic and transitive gene silencing in plants. All of these plant small RNAs are methylated at the 2’-hydroxyl group of the 3’ terminal nucleotide by HUA Enhancer 1 (HEN1), and this 3’ terminal 2’-O-methylation is thought to stabilize the small RNAs in plant cells. miRNAs, tasiRNAs and exosiRNAs are functionally similar to small RNAs in animal cells which are involved in posttranscriptional gene silencing or sequence-specific degradation of RNA in animals. The rasiRNAs, however, are unique to plants and function to direct de novo cytosine methylation at the cognate DNA, a transcriptional gene silencing mechanism known as RNA -directed DNA methylation (RdADM). RNA silencing induced by dsRNA has been extensively exploited to reduce gene activity in various eukaryotic systems, and a number of gene silencing technologies has been developed. Different organisms are often amenable to different gene silencing approaches. For instance, long dsRNA (at least 100 basepairs in length) is less suited to inducing RNA silencing in mammalian cells due to dsRNA-induced interferon responses, and so shorter dsRNAs (less than 30 basepairs) are generally used in mammalian cells, whereas in plants hairpin RNA (hpRNA) with a long dsRNA stem is highly effective. In plants, the different RNA silencing pathways have led to different gene silencing technologies, such as artificial miRNA, artificial tasiRNA and virus- induced gene silencing technologies. However, successful applications of RNA silencing in plants has so far been achieved primarily by using long hpRNA transgenes. A hpRNA transgene construct typically consists of an inverted repeat made up of fully complementary sense and antisense sequences of a target gene sequence (which when transcribed form the dsRNA stem of hpRNA) separated by a spacer sequence (forming the loop of hpRNA), which is inserted between a promoter and a transcription terminator for expression in plant cells. The spacer sequence functions to stabilize the inverted-repeat DNA in bacteria during construct preparation. The dsRNA stem of the resulting hpRNA transcript is processed by DCL proteins into siRNAs that direct target gene silencing. hpRNA transgenes have been widely used to knock down gene expression, modify metabolic pathways and enhance disease and pest resistance in plants for crop improvement, and many successful applications of the technology in crop improvement have now been reported (Guo et al., 2016; Kim et al., 2019). Recent studies have suggested, however, that hpRNA transgenes are subject to self-induced transcriptional repression compromising the stability and efficacy of target gene silencing. While all transgenes are potentially subject to position or copy number- dependent transcriptional silencing, hpRNA transgenes are unique as they generate siRNAs that can direct DNA methylation to their own sequence via the RdDM pathway, and this has the potential to cause transcriptional self-silencing. Whilst dsRNA induced gene silencing has proven to be a valuable tool in altering the phenotype of an organism, there is a need for alternate, preferably improved, dsRNA molecules which can be used for RNAi. SUMMARY OF THE INVENTION The inventors conceived of new designs of genetic constructs for producing RNA molecules which include one or more double-stranded RNA regions which comprise multiple non-canonically basepaired nucleotides or non-basepaired nucleotides, or both, including forms which have two or more loop sequences, herein called loop-ended dsRNA (IledRNA). These RNA molecules have one or more of the following features; they are easily synthesized, they accumulate to higher levels in plant cells upon transcription of the genetic constructs encoding them, they more readily form a dsRNA structure and induce efficient silencing of target RNA molecules in plant cells, and they may form circular RNA molecules upon processing in plant cells. The present inventors have also identified that the activity of genes that regulate flowering time in plants may be modulated by using RNA molecules applied either endogenously, or preferably exogenously to plant cells at an earlier time, for example to seeds that give rise to the plants. The RNA molecules may reduce or abolish the function of one or more genes involved in the timing of flowering, for example a repressor of flowering, and so promote flowering. Thus, the present disclosure also provides a method of influencing the timing of flowering of a plant. This may be used to reduce or suppress activity of a gene with ability to influence a flowering characteristic through reduced expression of the gene by targeting its RNA transcripts. This modulation may be used to promote synchronous flowering of male and female parent lines in hybrid seed production, for example. Another use is to advance or retard flowering according to the variation of weather, or to extend or reduce the growing season. The activity of the plant gene is preferably reduced as a result of under- expression within at least some cells of the plant. One goal of classical breeding and cultivation of plants is to select varieties with a definite time of flowering. Early flowering varieties make it possible to cultivate important crops in regions in which the plant species would not normally reach complete maturity. Later flowering varieties allow for increased or improved production of vegetative parts such as leaves, stems and tubers. Seed production in a previous generation of a late flowering variety is advantageously promoted by the use of RNA molecules of the invention. The selection of early flowering or late flowering varieties by classical breeding is however a very time-intensive process. The RNA molecules and methods of the present disclosure are advantageous in this context. In a first aspect, the present invention provides an RNA molecule comprising a first RNA component, a second RNA component which is covalently linked to the first RNA component and, optionally, one or more or all of (i) a linking ribonucleotide sequence which covalently links the first and second RNA components, (ii) a 5° leader sequence and (iii) a 3’ trailer sequence, wherein the first RNA component consists of, in 5’ to 3’ order, a first 5’ ribonucleotide, a first RNA sequence and a first 3’ ribonucleotide, wherein the first 5’ and 3’ ribonucleotides basepair with each other in the first RNA component, wherein the first RNA sequence comprises a first sense ribonucleotide sequence of at least 20 contiguous ribonucleotides, a first loop sequence of at least 4 ribonucleotides and a first antisense ribonucleotide sequence of at least 20 contiguous ribonucleotides, wherein the first antisense ribonucleotide sequence hybridises with the first sense ribonucleotide sequence in the RNA molecule, wherein the first antisense ribonucleotide sequence is capable of hybridising to a first region of a target RNA molecule which modulates the timing of plant flowering, wherein the second RNA component is covalently linked, via the linking ribonucleotide sequence if present or directly if the linking ribonucleotide sequence is not present, to the first 5° ribonucleotide or the first 3’ ribonucleotide, wherein the second RNA component consists of, in 5° to 3’ order, a second 5’ ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, wherein the second 5” and 3’ ribonucleotides basepair to each other in the RNA molecule, wherein the second RNA sequence comprises a second sense ribonucleotide sequence, a second loop sequence of at least 4 ribonucleotides and a second antisense ribonucleotide sequence, wherein the second sense ribonucleotide sequence hybridises with the second antisense ribonucleotide sequence in the RNA molecule, wherein the 5’ leader sequence, if present, consists of a sequence of ribonucleotides which is covalently linked to the first 5’ ribonucleotide if the second RNA component is linked to the first 3’ ribonucleotide or to the second 5° ribonucleotide if the second RNA component is linked to the first 5° ribonucleotide, and wherein the 3’ trailer sequence, if present, consists of a sequence of ribonucleotides which is covalently linked to the second 3’ ribonucleotide if the second RNA component is linked to the first 3’ ribonucleotide or to the first 3° ribonucleotide if the second RNA component is linked to the first 5° ribonucleotide. In a second aspect, the present invention provides an RNA molecule comprising a first RNA component, a second RNA component which is covalently linked to the first RNA component and, optionally, one or more or all of (i) a linking ribonucleotide sequence which covalently links the first and second RNA components, (ii) a 5° leader sequence and (iii) a 3’ trailer sequence, wherein the first RNA component consists of, in 5’ to 3’ order, a first 5’ ribonucleotide, a first RNA sequence and a first 3’ ribonucleotide, wherein the first 5° and 3’ ribonucleotides basepair, wherein the first RNA sequence comprises a first sense ribonucleotide sequence, a first loop sequence of at least 4 ribonucleotides and a first antisense ribonucleotide sequence, wherein the first sense ribonucleotide sequence and first antisense ribonucleotide sequence each of at least 20 contiguous ribonucleotides whereby the at least 20 contiguous ribonucleotides of the first sense ribonucleotide sequence fully basepair with the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence, wherein the at least 20 contiguous ribonucleotides of the first sense ribonucleotide sequence are identical in sequence to a first region of a target RNA molecule which modulates the timing of plant flowering, wherein the second RNA component is covalently linked, via the linking ribonucleotide sequence if present, to the first 5° ribonucleotide or the first 3’ ribonucleotide, wherein the second RNA component consists of, in 5° to 3’ order, a second 5’ ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, wherein the second 5° and 3’ ribonucleotides basepair, wherein the second RNA sequence comprises a second sense ribonucleotide sequence, a second loop sequence of at least 4 ribonucleotides and a second antisense ribonucleotide sequence, wherein the second sense ribonucleotide sequence basepairs with the second antisense ribonucleotide sequence, wherein the 5’ leader sequence, if present, consists of a sequence of ribonucleotides which is covalently linked to the first 5’ ribonucleotide if the second RNA component is linked to the first 3’ ribonucleotide or to the second 5° ribonucleotide if the second RNA component is linked to the first 5° ribonucleotide, and wherein the 3’ trailer sequence, if present, consists of a sequence of ribonucleotides which is covalently linked to the second 3’ ribonucleotide if the second RNA component is linked to the first 3’ ribonucleotide or to the first 3° ribonucleotide if the second RNA component is linked to the first 5° ribonucleotide. In these aspects, at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence are all capable of basepairing to nucleotides of the first region of the target RNA molecule. In an embodiment, the first sense ribonucleotide sequence is linked covalently to the first 5° ribonucleotide without any intervening nucleotides, or the first antisense ribonucleotide sequence is linked covalently to the first 3’ ribonucleotide without any intervening nucleotides, or both. In another embodiment, the RNA molecule comprises the linking ribonucleotide sequence, wherein the linking ribonucleotide sequence is less than 20 ribonucleotides. In an embodiment, the linking ribonucleotide sequence hybridizes to the target RNA molecule. In an embodiment, the linking ribonucleotide sequence is identical to a portion of the complement of the target RNA molecule. In another embodiment, the linking ribonucleotide sequence is between 1 and 10 ribonucleotides in length. In another embodiment, the RNA molecule comprises two or more sense ribonucleotide sequences, and antisense ribonucleotide sequences fully based paired thereto, which are identical in sequence to a region of a target RNA molecule. In an embodiment, the two or more sense ribonucleotide sequences are identical in sequence to different regions of the same target RNA molecule. In another embodiment, the two or more sense ribonucleotide sequences are identical in sequence to a region of different target RNA molecules. In another embodiment, the two or more sense ribonucleotide sequences have no intervening loop sequences. In an embodiment, the RNA molecule comprises two or more antisense ribonucleotide sequences, and sense ribonucleotide sequences fully based paired thereto, which are each complementary to a region of a target RNA molecule. In an embodiment, the two or more antisense ribonucleotide sequences are complementary to different regions of the same target RNA molecule. In another embodiment, the second of the two or more antisense ribonucleotide sequences are complementary to region of a different target RNA molecule than the first of the two or more antisense ribonucleotide sequences. In another embodiment, the two or more sense ribonucleotide sequences have no intervening loop sequences. In another embodiment, the RNA molecule is a single strand of ribonucleotides having a 5’ end, at least one sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully base paired with each sense ribonucleotide sequence over at least 21 contiguous nucleotides, at least two loop sequences and a 3’ end. In another embodiment, the RNA molecule is a single strand of ribonucleotides having a 5’ end, at least one sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully base paired with each sense ribonucleotide sequence over at least 21 contiguous nucleotides, at least two loop sequences and a 3’ end. In another embodiment, the RNA molecule is a single strand of ribonucleotides comprising a 5° end, the first RNA component comprising a first sense ribonucleotide sequence which is at least 21 nucleotides in length, at least one loop sequence, a first antisense ribonucleotide sequence which hybridises with the first sense ribonucleotide sequence over a length of at least 21 contiguous nucleotides, and the second RNA component comprising a second sense ribonucleotide sequence which is at least 21 nucleotides in length, a loop sequence, a second antisense ribonucleotide sequence which hybridises with the second sense ribonucleotide sequence over a length of at least 21 contiguous nucleotides, and a 3’ end, wherein the RNA molecule has only one 5’ end and only one 3’ end. In an embodiment, the ribonucleotide at the 5’ end and the ribonucleotide at the 3’ end are adjacent, each base paired and are not directly covalently bonded. In another embodiment, the RNA molecule comprises a first antisense ribonucleotide sequence which hybridizes to a first region of a target RNA, a second antisense ribonucleotide sequence which hybridizes to a second region of a target RNA, the second region of the target RNA being different to the first region of the target RNA, and the RNA molecule comprising only one sense ribonucleotide sequence which hybridizes to the target RNA, wherein the two antisense sequences are not contiguous in the RNA molecule. In another embodiment, the RNA molecule comprises a first sense ribonucleotide sequence which is at least 60% identical to a first region of a target RNA, a second sense ribonucleotide sequence which is at least 60% identical to a second region of a target RNA, the second region of the target RNA being different to the first region of the target RNA, and the RNA molecule comprising only one antisense ribonucleotide sequence which hybridizes to the target RNA, wherein the two sense sequences are not contiguous in the RNA molecule. In another embodiment, the RNA molecule has the 5’ leader sequence. In another embodiment, the RNA molecule has the 3° trailer sequence. In an embodiment, each ribonucleotide is covalently linked to two other nucleotides. In another embodiment, at least one or all of the loop sequences are longer than 20 nucleotides. In an embodiment, the RNA molecules has none, or one, or two or more bulges, or a double-stranded region of the RNA molecule comprises one, or two, or more nucleotides which are not basepaired in the double-stranded region. In another embodiment, the RNA molecule has three, four or more loops. In another embodiment, the RNA molecule only has two loops. In an embodiment, all of the loops are between 4 and 1,000 ribonucleotides, or between 4 and 200 ribonucleotides, in length. In another embodiment, all of the loops are between 4 and 50 ribonucleotides in length. In another embodiment, each loop is between 20 and 30 ribonucleotides in length. In a preferred embodiment, the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence are all capable of basepairing to nucleotides of the first region of the target RNA molecule. In this context, basepairing may be canonical or non-canonical, for example with at least some G:U basepairs. Independently for each G:U basepair, the G may be in the first region of the target RNA molecule or preferably in the first antisense ribonucleotide sequence. In an embodiment, the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence that are all capable of basepairing to nucleotides of the first region of the target RNA molecule do so by a canonical base pair. Alternatively, not all of the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence basepair to nucleotides of the first region of the target RNA molecule. For example, 1, 2, 3, 4 or 5 of the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence are not basepaired to the first region of the target RNA molecule. In an embodiment, the first sense ribonucleotide sequence is linked covalently to the first 5° ribonucleotide without any intervening nucleotides, or the first antisense ribonucleotide sequence is linked covalently to the first 3’ ribonucleotide without any intervening nucleotides, or both. In an embodiment, the RNA molecule comprises one or more linking ribonucleotide sequence, wherein the linking ribonucleotide sequence is related in sequence to the target RNA molecule, either identical at least in part to a region of the target RNA molecule or to its complement. In a preferred embodiment, the linking ribonucleotide sequence together with sense sequences in the first and second RNA components form part of one contiguous sense sequence, or together with antisense sequences in the first and second RNA components form part of one contiguous antisense sequence. In an embodiment, the RNA molecule comprises the linking ribonucleotide sequence, wherein the linking ribonucleotide sequence is less than 20 ribonucleotides. In an embodiment, the linking ribonucleotide sequence hybridizes to the target RNA molecule. In an embodiment, the linking ribonucleotide sequence is identical to a portion of the complement of the target RNA molecule. In an embodiment, the linking ribonucleotide sequence is between 1 and 50, or between 1 and 10 ribonucleotides, in length. In an embodiment, the RNA molecule comprises two or more sense ribonucleotide sequences, and antisense ribonucleotide sequences fully based paired thereto, which are identical in sequence to a region of a target RNA molecule. In an embodiment, the two or more sense ribonucleotide sequences are identical in sequence to different regions of the same target RNA molecule. In an algternate embodiment, the two or more sense ribonucleotide sequences are identical in sequence to a region of different target RNA molecules. In an embodiment, the two or more sense ribonucleotide sequences have no intervening loop sequences, i.e. they are contiguous relative to the target RNA molecule. In an embodiment, the RNA comprises two or more antisense ribonucleotide sequences, and sense ribonucleotide sequences fully based paired thereto, which are each complementary to a region of a target RNA molecule. In an embodiment, the two or more antisense ribonucleotide sequences are complementary to different regions of the same target RNA molecule. In an embodiment, the second of the two or more antisense ribonucleotide sequences are complementary to region of a different target RNA molecule than the first of the two or more antisense ribonucleotide sequences. In an embodiment, the RNA molecule is a single strand of ribonucleotides having a 5’ end, at least one sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully base paired with each sense ribonucleotide sequence over at least 21 contiguous nucleotides, at least two loop sequences and a 3” end. In an embodiment, the RNA molecule is a single strand of ribonucleotides having a 5’ end, at least one sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully base paired with each sense ribonucleotide sequence over at least 21 contiguous nucleotides, at least two loop sequences and a 3” end. In an embodiment, the RNA molecule is a a single strand of ribonucleotides comprising a 5” end, the first RNA component comprising a first sense ribonucleotide sequence which is at least 21 nucleotides in length, at least one loop sequence, a first antisense ribonucleotide sequence which hybridises with the first sense ribonucleotide sequence over a length of at least 21 contiguous nucleotides, and the second RNA component comprising a second sense ribonucleotide sequence which is at least 21 nucleotides in length, a loop sequence, a second antisense ribonucleotide sequence which hybridises with the second sense ribonucleotide sequence over a length of at least 21 contiguous nucleotides, and a 3’ end, wherein the RNA molecule has only one 5’ end and only one 3’ end. In an embodiment, the ribonucleotide at the 5° end and the ribonucleotide at the 3’ end are adjacent, each base paired and are not directly covalently bonded. In an embodiment, the RNA molecule comprises a first antisense ribonucleotide sequence which hybridizes to a first region of a target RNA, a second antisense ribonucleotide sequence which hybridizes to a second region of a target RNA, the second region of the target RNA being different to the first region of the target RNA, and the RNA molecule comprising only one sense ribonucleotide sequence which hybridizes to the target RNA, wherein the two antisense sequences are not contiguous in the RNA molecule. In an embodiment, the RNA molecule comprises a first sense ribonucleotide sequence which is at least 60% identical to a first region of a target RNA, a second sense ribonucleotide sequence which is at least 60% identical to a second region of a target RNA, the second region of the target RNA being different to the first region of the target RNA, and the RNA molecule comprising only one antisense ribonucleotide sequence which hybridizes to the target RNA, wherein the two sense sequences are not contiguous in the RNA molecule. In an embodiment, the RNA molecule has the 5° leader sequence. In an embodiment, the RNA molecule has the 3’ trailer sequence. In an embodiment, each ribonucleotide is covalently linked to two other nucleotides. Alternatively, the RNA molecule may be represented as a dumbbell shape (Figure 1) but have a gap or nick in one part of the double-stranded structure. In an embodiment, at least one or all of the loop sequences are longer than 20 nucleotides. In an embodiment, the RNA molecules has none, or one, or two or more bulges, or a double-stranded region of the RNA molecule comprises one, or two, or more nucleotides which are not basepaired in the double-stranded region. In an embodiment, the RNA molecules has three, four or more loops. In an embodiment, the RNA molecules has only has two loops. In an embodiment, the target RNA is in a plant cell. Examples of such plants cells include, but are not limited to, those from Arabidopsis, corn, canola, cotton, soybean, alfalfa, lettuce, wheat, barley, rice, legume, Medicago truncatula, sugarbeet or rye. The plant cell may be from a legume such as alfalfa or clover, a leafy vegetable e.g. lettuce, or a grass e.g. turfgrass. In an embodiment, the RNA molecule is present in a plant cell. In an embodiment, the RNA molecule of the invention is produced / expressed in a cell, such as for example a bacterial cell or other microbial cell, which is different to the cell comprising the target RNA. In a preferred embodiment, the microbial cell is a cell in which the RNA molecule is produced by transcription from a genetic construct encoding the RNA molecule, wherein the RNA molecule is substantially, or preferably predominantly, not processed in the microbial cell by cleavage within one or more loop sequences, one or more dsRNA regions, or both. For example, the microbial cell is a yeast cell or another fungal cell which does not have a Dicer enzyme. A greatly preferred cell for production of the RNA molecule is a Saccharomyces cerevisiae cell. The microbial cell may be living, or may have been killed by some treatment such as heat treatment, or may be in the form of a dried powder. In an embodiment, at least one or all of the loop sequences of the RNA molecule are longer than 20 nucleotides. In a preferred embodiment, at least one of the loops of the RNA molecule is between 4 and 1,200 ribonucleotides in length, or between 4 and 1000 ribonucleotides in length. In a more preferred embodiment, all of the loops are between 4 and 1,000 ribonucleotides in length. In a more preferred embodiment, at least one of the loops of the RNA molecule is between 4 and 200 ribonucleotides in length. In an even more preferred embodiment, all of the loops are between 4 and 200 ribonucleotides in length. In an even more preferred embodiment, at least one of the loops of the RNA molecule is between 4 and 50 ribonucleotides in length. In a most preferred embodiment, all of the loops are between 4 and 50 ribonucleotides in length. In embodiments, the minimum length of the loop is 20 nucleotides, 30 nucleotides, 40 nucleotides, or 50 nucleotides. In an embodiment, each loop of the RNA molecule is independently between 20 and 50 ribonucleotides, or between 20 and 40 ribonucleotides or between 20 and 30 ribonucleotides in length. In an embodiment, the target RNA encodes a protein. In another embodiment, the RNA molecule may comprise a region of a nucleotide sequence set forth in SEQ ID NO:146, SEQ ID NO:147, or SEQ ID NOs:151-152 (wheat), SEQ ID NOs:154-155 (barley), SEQ ID NOs:156-164 (rice), SEQ ID NOs:165-178 (maize), SEQ ID NOs:179-185 (Brassica napus), SEQ ID NOs:186-187 and SEQ ID NO:210 (Medicago truncatula), SEQ ID NOs:188-190 (alfalfa), SEQ ID NOs:191-204 (soybean), SEQ ID NOs:205-207 (sugarbeet), SEQ ID NOs:208-209 (Brassica rapa), SEQ ID NOs:211-220 (onion) and SEQ ID NOs:221- 228 (lettuce), or a complement (antisense) of a region of the sequence, or both the region and the complement, or a nucleotide sequence 95% identical thereto. In an embodiment, the RNA molecule of the invention comprises a sense and an antisense sequence from a region of an RNA transcript from a gene whose cDNA corresponds to one of the SEQ ID NOs listed above, or a nucleotide sequence 95% or preferably 99% identical thereto. Such sequence is preferably derived from the RNA transcript of a naturally occurring homolog of the gene in that plant species. In another embodiment, RNA molecules of the invention may comprise a a region of a nucleotide sequence set forth in SEQ ID NO:146, SEQ ID NO:147 or SEQ ID NOs:151-228. In an embodiment of the aspects, the second RNA component is characterised in that: i) the second sense ribonucleotide sequence consists of at least 20 contiguous ribonucleotides covalently linked, in 5’ to 3’ order, the second 5’ ribonucleotide, a third RNA sequence and a third 3’ ribonucleotide, ii) the second antisense ribonucleotide sequence consists of at least 20 contiguous ribonucleotides covalently linked, in 5° to 3’ order, a third 5’ ribonucleotide, a fourth RNA sequence and the second 3’ ribonucleotide, iii) the second 5’ ribonucleotide basepairs with the second 3’ ribonucleotide, iv) the third 3’ ribonucleotide basepairs with the third 5° ribonucleotide, wherein the chimeric RNA molecule is capable of being processed in a plant cell or in vitro whereby the second antisense ribonucleotide sequence is cleaved to produce short antisense RNA (asRNA) molecules of 20-24 ribonucleotides in length. Most preferably, the asRNA molecules produced from the second antisense sequence are capable of reducing expression of the target RNA, either without or in combination with asRNAs produced from the first antisense sequence of the first RNA component. It is more preferred that between 5% and 40% of the ribonucleotides of the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence, and / or the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence, and / or every sense ribonucleotide sequence and its corresponding antisense ribonucleotide sequence which hybridise, in total, are either basepaired in a non- canonical basepair or are not basepaired, and / or the dsRNA region formed between the complementary sense and antisense sequences does not comprise 20 contiguous canonical basepairs. More preferably, about 12%, about 15%, about 18%, about 21%, about 24%, about 27%, about 30%, between 10% and 30%, or between 15% and 30%, or even more preferably between 16% and 25%, of the ribonucleotides of a sense ribonucleotide sequence and its corresponding antisense ribonucleotide sequence, preferably for every dsRNA region in the RNA molecule, in total, are either basepaired in a non-canonical basepair or are not basepaired. Even more preferably, about 12%, about 15%, about 18%, about 21%, about 24%, about 27%, about 30%, between 10% and 30%, or between 15% and 30%, or even more preferably between 16% and 25%, of the ribonucleotides of the dsRNA region(s) in the RNA molecule, in total, are basepaired in non-canonical basepairs and all of the other ribonucleotides of the dsRNA region(s) in the RNA molecule are basepaired in canonical basepairs. In preferred embodiments, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, or 100% of the non-canonical basepairs in the first or second dsRNA region, or all dsRNA regions in total, are G:U basepairs. Most preferably, in these embodiments, (a) the chimeric RNA molecule or at least some of the asRNA molecules, or both, are capable of reducing the expression or activity of a target RNA molecule which modulates the timing of plant flowering, or (b) the first and second antisense ribonucleotide sequences, preferably every antisense ribonucleotide sequence in the RNA molecule, comprises a sequence of at least 20 contiguous ribonucleotides which is at least 50% identical in sequence to a region of the complement of the target RNA molecule, preferably at least 60% identical, more preferably at least 70% identical, even more preferably at least 80% identical, most preferably at least 90% identical or 100% identical to the region of the complement of the target RNA molecule, or both (a) and (b). In a third aspect, the present invention provides a chimeric ribonucleic acid (RNA) molecule, comprising a double-stranded RNA (dsRNA) region which comprises a first sense ribonucleotide sequence of at least 20 contiguous nucleotides in length and a first antisense ribonucleotide sequence of at least 20 contiguous nucleotides in length, whereby the first sense ribonucleotide sequence and the first antisense ribonucleotide sequences are capable of hybridising to each other to form the dsRNA region, wherein i) the first sense ribonucleotide sequence consists of, covalently linked in 5° to 3’ order, a first 5’ ribonucleotide, a first RNA sequence and a first 3° ribonucleotide, ii) the first antisense ribonucleotide sequence consists of, covalently linked in 5” to 3’ order, a second 5’ ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, iii) the first 5° ribonucleotide basepairs with the second 3’ ribonucleotide to form a terminal basepair of the dsRNA region, iv) the second 5’ ribonucleotide basepairs with the first 3’ ribonucleotide to form a terminal basepair of the dsRNA region, v) between about 5% and about 40% of the ribonucleotides of the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence, in total, are either basepaired in a non-canonical basepair or are not basepaired, vi) the dsRNA region does not comprise 20 contiguous canonical basepairs, vii) the RNA molecule is capable of being processed in a plant cell or in vitro whereby the first antisense ribonucleotide sequence is cleaved to produce short antisense RNA (asRNA) molecules of 20-24 ribonucleotides in length, viii) the RNA molecule or at least some of the asRNA molecules, or both, are capable of reducing the expression or activity of a target RNA molecule which modulates the timing of plant flowering, and ix) the RNA molecule is capable of being made enzymatically by transcription in vitro or in a cell, or both. In an embodiment, the first sense ribonucleotide sequence is covalently linked to the first antisense ribonucleotide sequence by a first linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides, or between 4 and 1,000 ribonucleotides, or between 4 and 200 ribonucleotides, or between 4 and 50 ribonucleotides, or at least 10 nucleotides, or between 10 and 1,000 ribonucleotides, or between 10 and 200 ribonucleotides, or between 10 and 50 ribonucleotides, in length, whereby the first linking ribonucleotide sequence is covalently linked to either the second 3’ ribonucleotide and the first 5° ribonucleotide or, preferably, to the first 3’ ribonucleotide and the second 5” ribonucleotide, so that the sequences are comprised in a single, contiguous strand of RNA. In another embodiment, the first linking ribonucleotide sequence is covalently linked to either the second 3’ ribonucleotide and the first 5° ribonucleotide or, preferably, to the first 3’ ribonucleotide and the second 5’ ribonucleotide, so that the sequences are comprised in a single, contiguous strand of RNA. In an embodiment, the loop sequence in the chimeric RNA molecule comprises one or more binding sequences which are complementary to an RNA molecule which is endogenous to the plant cell, and / or the loop sequence in the RNA molecule comprises an open reading frame which encodes a polypeptide or a functional polynucleotide. In its simplest form, such an chimeric RNA molecule is referred to as a hairpin RNA (hpRNA). In a more preferred embodiment, between about 5% and about 40% of the ribonucleotides of the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence of the dsRNA, in total, are basepaired in non-canonical basepairs, preferably G:U basepairs. That is, all of the ribonucleotides of the first sense ribonucleotide sequence are basepaired to ribonucleotides of the first antisense ribonucleotide sequence, either in canonical basepairs or non-canonical basepairs, whereby the dsRNA region comprises 20 contiguous basepairs including some non- canonical basepairs. The dsRNA region thereby does not comprise 20 contiguous canonical basepairs. In a more preferred embodiment of the hpRNA of the invention, the first antisense ribonucleotide sequence is fully complementary to a region of the target RNA. In this embodiment, the first sense ribonucleotide sequence is different in sequence to the region of the target RNA by the substitution of C nucleotides in the region of the target RNA with U nucleotides in the hpRNA. Such molecules are exemplified in the hairpin RNAs comprising G:U basepairs in Examples 6-11. In preferred embodiments, the length of the first antisense ribonucleotide sequence is 20 to about 1000 nucleotides, or 20 to about 500 nucleotides, or other lengths as described herein. More preferably, the hpRNA is produced in, or introduced into, a plant cell. In this embodiments, the target RNA may be a transcript of an endogenous gene in the plant cell. In an embodiment, the first antisense ribonucleotide sequence is fully complementary to a region of the target RNA and the first sense ribonucleotide sequence is different in sequence to the region of the target RNA by the substitution of C nucleotides in the region of the target RNA with U nucleotides. In a more preferred embodiment, the chimeric RNA molecule comprises a second sense ribonucleotide sequence and the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence are linked by a first linking ribonucleotide sequence comprising a loop sequence of at least 4 nucleotides in length, whereby the first linking ribonucleotide sequence is covalently linked to the first 3’ ribonucleotide and the second 5° ribonucleotide, and the RNA molecule further comprises a second linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides in length and which is covalently linked to the second 3’ ribonucleotide and the second sense ribonucleotide sequence, thereby forming an ledRNA structure. In an alternative preferred embodiment, the chimeric RNA molecule comprises a second antisense ribonucleotide sequence and the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence are linked by a first linking ribonucleotide sequence comprising a loop sequence of at least 4 nucleotides in length, whereby the first linking ribonucleotide sequence is covalently linked to the second 3° ribonucleotide and the first 5° ribonucleotide, and the RNA molecule further comprises a second linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides in length and which is covalently linked to the second 3’ ribonucleotide and the second antisense ribonucleotide sequence. In another preferred embodiment, the chimeric RNA molecule comprises a second sense ribonucleotide sequence and a second antisense ribonucleotide sequence, wherein the second sense ribonucleotide sequence and the second antisense ribonucleotide sequences are capable of hybridising to each other to form a second dsRNA region, and the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence are linked by a first linking ribonucleotide sequence comprising a loop sequence of at least 4 nucleotides in length, whereby the first linking ribonucleotide sequence is covalently linked to the first 3° ribonucleotide and the second 5’ ribonucleotide, and the RNA molecule further, or optionally, comprises a second linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides in length and which is covalently linked to the second 3’ ribonucleotide and the second sense ribonucleotide sequence or which covalently links the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence. In an embodiment, the chimeric RNA molecule comprises a second sense ribonucleotide sequence and a second antisense ribonucleotide sequence and the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence are linked by a first linking ribonucleotide sequence comprising a loop sequence of at least 4 nucleotides in length, whereby the first linking ribonucleotide sequence is covalently linked to the second 3’ ribonucleotide and the first 5° ribonucleotide, and the RNA molecule further comprises a second linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides in length and which is covalently linked to the first 3’ ribonucleotide and the second antisense ribonucleotide sequence, or which covalently links the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence. In an embodiment, the chimeric RNA molecule comprises a second sense ribonucleotide sequence and a second antisense ribonucleotide sequence and the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence are linked by a first linking ribonucleotide sequence comprising a loop sequence of at least 4 nucleotides in length, whereby the first linking ribonucleotide sequence is covalently linked to the second 3’ ribonucleotide and the first 5° ribonucleotide, and the RNA molecule further comprises a second linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides in length and which is covalently linked to the first 3’ ribonucleotide and the second antisense ribonucleotide sequence, or which covalently links the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence. In an embodiment, the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence each comprise at least 20 contiguous nucleotides in length. In an embodiment, the first and second sense ribonucleotide sequences are covalently linked by an intervening ribonucleotide sequence which is unrelated in sequence to the target RNA molecule, or which is related in sequence to the target RNA molecule, or the first and second sense ribonucleotide sequences are covalently linked without an intervening ribonucleotide sequence. In an embodiment, the first and second antisense ribonucleotide sequences are covalently linked by an intervening ribonucleotide sequence which is unrelated in sequence to the complement of a target RNA molecule, or which is related in sequence to the complement of a target RNA molecule, or the first and second antisense ribonucleotide sequences are covalently linked without an intervening ribonucleotide sequence. In an embodiment, the first and second sense ribonucleotide sequences may form one contiguous sense ribonucleotide region having at least 50% identity in sequence to a target RNA molecule. In another embodiment, the first and second antisense sense ribonucleotide sequences may form one contiguous antisense ribonucleotide region having at least 50% identity in sequence to the complement of a target RNA molecule. In another embodiment, the RNA molecule comprises a first sense ribonucleotide sequence which is at least 60% identical to a first region of a target RNA, a second sense ribonucleotide sequence which is at least 60% identical to a second region of a target RNA, the second region of the target RNA being different to the first region of the target RNA, and the RNA molecule comprising only one antisense ribonucleotide sequence which hybridizes to the target RNA, wherein the two sense sequences are not contiguous in the RNA molecule. In an embodiment, the first and second regions of the target RNA are contiguous in the target RNA molecule. Alternatively, they are not contiguous. In preferred embodiments, the first and second sense ribonucleotide sequences are each, independently, at least 70%, at least 80%, at least 90%, at least 95%, or at least 99% identical to the respective region of target RNA ie. the first sense sequence may be at least 70% identical to its target region and the second sequence at least 80% identical to its target sequence, etc. In an embodiment, between 5% and 40% of the ribonucleotides of the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence, in total, are either basepaired in a non-canonical basepair or are not basepaired, preferably basepaired in G:U basepairs, wherein the second dsRNA region does not comprise 20 contiguous canonical basepairs, and wherein the RNA molecule is capable of being processed in a eukaryotic cell or in vitro whereby the second antisense ribonucleotide sequence is cleaved to produce short antisense RNA (asRNA) molecules of 20-24 ribonucleotides in length. In an embodiment, each linking ribonucleotide sequence is independently between 4 and about 2000 nucleotides in length, preferably between 4 and about 1200 nucleotides in length, more preferably between 4 and about 200 nucleotides in length and most preferably between 4 and about 50 nucleotides in length. In an embodiment, the chimeric RNA molecule further comprises a 5’ leader sequence or a 3’ trailer sequence, or both. In a fourth aspect, the present invention provides a chimeric RNA molecule comprising a first RNA component and a second RNA component which is covalently linked to the first RNA component, wherein the first RNA component comprises a first double-stranded RNA (dsRNA) region, which comprises a first sense ribonucleotide sequence and a first antisense ribonucleotide sequence which are capable of hybridising to each other to form the first dsRNA region, and a first intervening ribonucleotide sequence of at least 4 nucleotides which covalently links the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence, wherein the second RNA component comprises a second sense ribonucleotide sequence, a second antisense ribonucleotide sequence and a second intervening ribonucleotide sequence of at least 4 ribonucleotides which covalently links the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence, wherein the second sense ribonucleotide sequence hybridises with the second antisense ribonucleotide sequence in the RNA molecule, wherein in the first RNA component, i) the first sense ribonucleotide sequence consists of at least 20 contiguous ribonucleotides covalently linked, in 5° to 3” order, a first 5° ribonucleotide, a first RNA sequence and a first 3’ ribonucleotide, ii) the first antisense ribonucleotide sequence consists of at least 20 contiguous ribonucleotides covalently linked, in 5° to 3’ order, a second 5’ ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, iii) the first 5° ribonucleotide basepairs with the second 3’ ribonucleotide, iv) the second 5’ ribonucleotide basepairs with the first 3’ ribonucleotide, v) between 5% and 40% of the ribonucleotides of the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence, in total, are either basepaired in a non-canonical basepair or are not basepaired, and vi) the first dsRNA region does not comprise 20 contiguous canonical basepairs, wherein the chimeric RNA molecule is capable of being processed in a plant cell or in vitro whereby the first antisense ribonucleotide sequence is cleaved to produce short antisense RNA (asRNA) molecules of 20-24 ribonucleotides in length, and wherein (a) the chimeric RNA molecule or at least some of the asRNA molecules, or both, are capable of reducing the expression or activity of a target RNA molecule which modulates plant flowering, or (b) the first antisense ribonucleotide sequence comprises a sequence of at least 20 contiguous ribonucleotides which is at least 50% identical in sequence, preferably at least 90% or 100% identical in sequence, to a region of the complement of the target RNA molecule, or (¢) both (a) and (b). In an embodiment of the two above aspects, the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence are all capable of basepairing to nucleotides of a first region of the target RNA molecule. In an embodiment of the two above aspects, the chimeric RNA molecule comprises two or more antisense ribonucleotide sequences, and sense ribonucleotide sequences based paired thereto, which antisense sequences are each complementary, preferably fully complementary, to a region of a target RNA molecule. The regions of the target RNA molecule to which they are complementary may or may not be contiguous in the target RNA molecule. In an embodiment, the two or more antisense ribonucleotide sequences are complementary to different regions of the same target RNA molecule. In an alternate embodiment, the two or more antisense ribonucleotide sequences are complementary to regions of different target RNA molecules. In an embodiment, the two or more antisense ribonucleotide sequences have no intervening loop sequences, i.e. they are contiguous relative to the complement of the target RNA molecule. In a preferred embodiment, one or both of the two or more antisense ribonucleotide sequences and sense ribonucleotide sequences basepair along their full length through canonical basepairs, or through some canonical and some non- canonical basepairs, preferably G:U basepairs. The RNA molecule may comprise a 5’-leader sequence and / or a 3’-trailer sequence. In an embodiment of the two above aspects, the chimeric RNA molecule comprises a hairpin RNA (hpRNA) structure having a 5° end, a sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully base paired with the sense ribonucleotide sequence over at least 21 contiguous nucleotides, an intervening loop sequence and a 3’ end. The RNA molecule may comprise a 5’-leader sequence and / or a 3’-trailer sequence. In an embodiment of the two above aspects, the chimeric RNA molecule comprises a single strand of ribonucleotides having a 5° end, at least one sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully base paired with each sense ribonucleotide sequence over at least 21 contiguous nucleotides, at least two loop sequences and a 3’ end. The order 5’ to 3° may be the sense ribonucleotide sequence and then the antisense ribonucleotide sequence, or vice versa. In an embodiment, the ribonucleotide at the 5” end and the ribonucleotide at the 3” end are adjacent, each base paired and are not directly covalently bonded, see for example Figure 1. In an embodiment of the two above aspects, between about 15% and about 30%, or between about 16% and about 25%, of the ribonucleotides of the sense ribonucleotide sequence and the antisense ribonucleotide sequence, in total, are either basepaired in a non-canonical basepair or are not basepaired, preferably basepaired in non-canonical basepairs, more preferably basepaired in G:U basepairs. In an embodiment of the two above aspects, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, or 100% of the non- canonical basepairs are G:U basepairs. In an embodiment of the two above aspects, less than 25%, less than 20%, less than 15%, less than 10%, less than 5%, less than 1% or none, of the ribonucleotides in the dsRNA region are not basepaired. In an embodiment of the two above aspects, every one in four to every one in six ribonucleotides in the dsRNA region form a non-canonical basepair or are not basepaired, preferably form a G:U basepair. In an embodiment of the two above aspects, the dsRNA region does not comprise 8 contiguous canonical basepairs. In an embodiment of the two above aspects, the dsRNA region comprises at least 8 contiguous canonical basepairs, preferably at least 8 but not more than 12 contiguous canonical basepairs. In an embodiment of the two above aspects, all of the ribonucleotides in the dsRNA region, or in each dsRNA region, are base-paired with a canonical basepair or a non-canonical basepair. In an embodiment of the two above aspects, one or more ribonucleotides of the sense ribonucleotide sequence or one or more ribonucleotides of the antisense ribonucleotide sequence, or both, are not basepaired. In an embodiment of the two above aspects, the antisense RNA sequence is less than 100% identical, or between about 80% and 99.9% identical, or between about 90% and 98% identical, or between about 95% and 98% identical, in sequence to the complement of a region of the target RNA molecule. In an embodiment of the two above aspects, the antisense RNA sequence is 100% identical in sequence to a region of the target RNA molecule. In an embodiment of the two above aspects, the sense and / or antisense ribonucleotide sequence, preferably both, is at least 50, at least about 100, at least about 200, at least about 300, at least about 400, at least about 500, at least about 600, at least about 700, at least about 800, at least about 900, at least about 1,000, or about 100 to about 1,000, or 20 to about 1000 nucleotides, or 20 to about 500 nucleotides, in length. In an embodiment of the two above aspects, the number of ribonucleotides in the sense ribonucleotide sequence is between about 90% and about 110% of the number of ribonucleotides in the antisense ribonucleotide sequence. In an embodiment of the two above aspects, the number of ribonucleotides in the sense ribonucleotide sequence is the same as the number of ribonucleotides in the antisense ribonucleotide sequence. In an embodiment of the two above aspects, the chimeric RNA molecule further comprises a 5’ extension sequence which is covalently linked to the first 5’ ribonucleotide or a 3’ extension sequence which is covalently linked to the second 3” ribonucleotide, or both. In an embodiment of the two above aspects, the chimeric RNA molecule further comprises a 5’ extension sequence which is covalently linked to the second 5’ ribonucleotide or a 3’ extension sequence which is covalently linked to the first 3” ribonucleotide, or both. In an embodiment of the two above aspects, the chimeric RNA molecule comprises two or more dsRNA regions which are the same or different. In an embodiment of the two above aspects, when expressed in a plant cell more asRNA molecules are formed that are 22 and / or 20 ribonucleotides in length when compared to processing of an analogous RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs. In an embodiment, an RNA molecule of the first or second aspect is also a chimeric RNA meolceule of the third or fourth aspects. In an embodiment of each of the above aspects, the target RNA encodes VERNALIZATION1 (VRND), VERNALIZATION2 (VRN2), EARLYINSHORTDAYS4, FLOWERING LOCUS T1 (FT1), FLOWERING LOCUS T2 (FT2), Flowering Locus C (FLC), FRIGIDA (FRI) or CONSTANS in the plant species of interest. In an embodiment of each of the above aspects, the target RNA comprises a region of a nucleotide sequence set forth in any one or more of SEQ ID NO’s 146, 147, or 151 to 228 (where the T’s are replaced with U’s), or a complement (antisense) of the region of the sequence, or both the region and the complement, or a nucleotide sequence 95%, preferably, 99%, identical thereto (where the T's are replaced with U’s). In an embodiment, the region is at least 15, at least 16, a least 17, at least 18, at least 19, at least 20 or at least 21 nucleotides in length. In an embodiment of each of the above aspects, target RNA is a gene transcript of the following from wheat, with Accession Nos of the genes or proteins in parentheses: VRNI1 / VRN-Al (KR422423.1; SEQ ID NO:151); VRN2 (ZCCT1, TaVRN2-B; SEQ ID NO:145) (AAS58481.1); TaFT (Accession No. AY705794.1; SEQ ID NO:152) or homologous genes in other species, preferably cereal species. In an embodiment of each of the above aspects, the target RNA is a gene transcript of the one of the following from barley: HvVRN1 (AY896051; SEQ ID NO:153), HvVRN2 (AY687931, AY485978; SEQ ID NO:154) or HVFT (DQ898519; SEQ ID NO:155), or homologous genes in other species, preferably cereal species. In an embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following from canola, BnFLC1 (AY036888, Bna.FLC.A10, BnaA10g22080D; SEQ ID NO:179); BnFLC2 (AY036889; SEQ ID NO:180); BnFLC3 (AY036890, SEQ ID NO:181); BnFLC4 (AY036891; SEQ ID NO:182); BnFLC5 (AY036892; SEQ ID NO:183); BnFRI (BnaA03gl13320D; SEQ ID NO:184); BnFT (BnaA02g12130D; SEQ ID NO:185) or homologous genes in other species. In an embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following from Arabidopsis, FRI (AT4G00650); FLC (AT5G10140); VRN1 (AT3G18990); VRN2 (AT4G16845); VIN3 (AT5G57380); FT (AT1G65480); SOC1 (AT2G45660); CO (constans) (AT5G15840); LFY (AT5G61850); AP1 (AT1G69120) or homologous genes in other species. In an embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following from rice, OsPhyB (OSNPB_030309200; SEQ ID NO:156); OsCol4 (HC084637; SEQ ID NO:157); RFT1 (OSNPB_070486100; SEQ ID NO:158); OsSNB (OSNPB_070235800; SEQ ID NO:159); OsIDS1 (0s03g0818800; SEQ ID NO:160); OsGI (OSNPB_010182600; SEQ ID NO:161), OsMADS50 (SEQ ID NO:162), OsMADSS55 (SEQ ID NO:163) or OsLFY (SEQ ID NO:164), or homologous genes in other species. In an embodiment of each of the above aspects, the target RNA is a gene transcript of the one of the following from maize (Zea mays): ZmMADS1 / ZmM5 (LOC542042, HM993639; SEQ ID NO:), PHYAL (AY234826; SEQ ID NO:166), PHYA2 (AY260865; SEQ ID NO:167), PHYB1 (AY234827; SEQ ID NO:168), PHYB2 (AY234828; SEQ ID NO:169), PHYC1 (AY234829; SEQ ID NO:170), PHYC2 (AY234830; SEQ ID NO:171), ZmLD (AF166527; SEQ ID NO:172), ZmFL1 (AY179882; SEQ ID NO:173), ZmFL2 (AY179881; SEQ ID NO:174), DWARF8 (AF413203; SEQ ID NO:175), ZmAN1 (L37750; SEQ ID NO:176), ZmID1 (AF058757; SEQ ID NO:177), ZCN8 (LOC100127519; SEQ ID NO:178), or homologous genes in other species, preferably cereal species. In an embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following from Medicago truncatula, MtFTal (HQ721813; SEQ ID NO:186); MtFTbl (HQ721815; SEQ ID NO:187), MtYFL (BT053010, SEQ ID NO:210), MtSOCla (Medtr07g075870), MtSOC1b (Medtr08g033250), MtSOClc (Medtr08g033220), or homologous genes in other species. In another embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following from alfalfa (Medicago sativa), MsFRI-L (SEQ ID NO:188), MsSOCla (SEQ ID NO:189), or MsFT (SEQ ID NO:190), or homologous genes in other species. In another embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following from soybean (Glycine max): encoded by the gene GLYMA_05G148700 with any one or more of the following transcript variants GmFLC-X1 (SEQ ID NO:191), GmFLC-X2 (SEQ ID NO:192) GmFLC-X3 (SEQ ID NO:193), GmFLC-X4 (SEQ ID NO:194), GmFLC-X5 (SEQ ID NO:195), GmFLC-X6 (SEQ ID N0:196), GmFLC-X7 (SEQ ID NO:197), GmFLC-X8 (SEQ ID NO:198), or GmFLC-X9 (SEQ ID NO:199), or SUPPRESSOR OF FRI (SEQ ID NO:200), GmFRI (SEQ ID NO:201), GmFT2A (SEQ ID N0O:202), GmPHYA3 (SEQ ID NO:203), or GIGANTEA (SEQ ID NO:204), or homologous genes in other species. In another embodiment of each of the above aspects, the target RNA is a gene transcript of the following from sugarbeet (Beta vulgaris), BVBTC1 (HQ709091, SEQ ID NO:205), preferably BvFT1 (HM448909.1, SEQ ID NO:206) and / or BvFT2 (HM448911, SEQ ID NO:207), where RNAi-induced down-regulation of the BvFT1- BVFT2 module led to a strong delay in bolting after vernalization by several weeks, or BvFL1 (DQ189214, DQ189215), or homologous genes in other species. In another embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following genes from Brassica rapa, which may be turnip, cabbage, bok choi, turnip rape or related crucifers: BrFLC2 (AH012704, SEQ ID NO:208), BrFT (Bra004928) or BrFRI (HQ615935, SEQ ID NO:209), or homologous genes in other species. In another embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following from cotton (Gossypium hirsutum): GhCO (Gorai.008G059900), GhFLC (Gorai.013G069000), GhFRI (Gorai.003G118000), GhFT (Gorai.004G264600), GhLFY (Gorai.001G053900), GhPHYA (Gorai.007G292800, Gorai.013G203900), GhPHYB (Gorai.011G200200), GhSOC1 (Gorai.008G115200), GhVRN1 (Gorai.002G006500, Gorai.005G240900, Gorai.012G150900, Gorai.013G040000), GhVRN2 (Gorai.003G176300), GhVRNS (Gorai.009G023200), or homologous genes in other species. In another embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following from onion (Allium cepa): AcGI (GQ232756, SEQ ID NO:211), AcFKF (GQ232754, SEQ ID NO:212), AcZTL (GQ232755, SEQ ID NO:213), AcCOL (GQ232751, SEQ ID NO:214), AcFTL (CF438000, SEQ ID NO:215), AcFT1 (KC485348, SEQ ID NO:216), AcFT2 (KC485349, SEQ ID NO:217), AcFT6 (KC485353, SEQ ID NO:218), AcPHYA (GQ232753, SEQ ID NO:219), AcCOP1 (CF451443, SEQ ID NO:220), or homologous genes in other species. In another embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following from asparagus (Asparagus officinalis): FPA (LOC109824259, LOC109840062), TWIN SISTER of FT-like (LOC109835987), MOTHER of FT (LOC109844838), FCA-like (LOC109841154, LOC109821266), PHOTOPERIOD-INDEPENDENT EARLY FLOWERING 1 (LOC109834006), FLOWERING LOCUS T-like (LOC109830558, LOC109825338, LOC109824462), Flowering locus K (LOC109847537), Flowering time control protein FY (LOC109844014), flowering time control protein FCA-like (LOC109842562), or homologous genes in other species. In another embodiment of each of the above aspects, the target RNA is a gene transcript of one of the following from lettuce (Lacruca sativa): LsFT (LOC111907824, SEQ ID NO:221), TFL1-like (LOC111903066, SEQ ID NO:222), TFL] homolog 1-like (LOC111903054, SEQ ID NO:223), LsFLC (LOC111876490, JI588382, SEQ ID NO:224), LsSOCI-like (LOC111912847, SEQ ID NO:225, LOCI111880753, SEQ ID NO:226, LOC111878575, SEQ ID NO:227), TsLFY (LC164345.1, XM_023888266.1, SEQ ID NO:228), or homologous genes in other species. In an embodiment of each of the above aspects, the target RNA is a miRNA. Examples of such targets include, but are not limited to, miR-156 or miR-172. In an embodiment of each of the above aspects, the RNA molecule or chimeric RNA molecule reduces the time to flowering compared to an isogenic plant lacking the RNA molecule or chimeric RNA molecule. In an embodiment, the plant is Arabidopsis, cor, canola, cotton, soybean, alfalfa, lettuce, wheat, barley, rice, legume, Medicago truncatula, sugarbeet or rye. In an embodiment, the plant is Arabidopsis, corn, canola, cotton, soybean, wheat, barley, rice, legume, Medicago truncatula, sugarbeet or rye. The plant may be from alfalfa or clover, a leafy vegetable e.g. lettuce, or a grass e.g. turfgrass. In an embodiment, the first and second regions of the target RNA are contiguous in the target RNA. Alternatively, they are not contiguous. In an embodiment of each of the above aspects, the RNA molecule or chimeric RNA molecule delays the time to flowering compared to an isogenic plant lacking the RNA molecule or chimeric RNA molecule. In an embodiment, the plant is a grass, where the target gene is a homolog of a cereal gene, as above. In an embodiment of each of the above aspects, the plant is genetically unmodified. In an embodiment of each of the above aspects, the RNA molecule comprises a 5’ leader sequence or 5’ extension sequence. In an embodiment, the RNA molecule comprises a 3” trailer sequence or 3’ extension sequence. In a preferred embodiment, the RNA molecule comprises both the 5’ leader / extension sequence and the 3’ trailer / extension sequence. In an embodiment of each of the above aspects, at least one loop sequence in the RNA molecule comprises one or more binding sequences which are complementary to an RNA molecule which is endogenous to the plant cell, such as, for example, an miRNA or other regulatory RNA in the plant cell. As would readily be understood, this feature may be in combination with any of the loop length features, non-canonical basepairing and any of the other features described above for the RNA molecule. In an embodiment, at least one loop sequence comprises multiple binding sequences for a miRNA, or binding sequences for multiple miRNAs, or both. In an embodiment, at least one loop sequence in the RNA molecule comprises an open reading frame which encodes a polypeptide or a functional polynucleotide. The open reading frame is preferably operably linked to a translation initiation sequence, whereby the open reading frame is capable of being translated in a plant cell of interest. For example, the translation initiation sequence comprises, or is comprised in, an internal ribosome entry site (IRES). The IRES is preferably a plant IRES. The translated polypeptide is preferably 50-400 amino acid residues in length, or 50-300 or 50-250, or 50-150 amino acid residues in length. Such RNA molecules, when produced in a plant cell, are capable of being processed to form circular RNA molecules comprising most or all of the loop sequence and which are capable of being translated to provide high levels of the polypeptide. In an embodiment of each of the above aspects, the RNA molecule has none, or one, or two or more bulges in a double-stranded region. In this context, a bulge is a nucleotide, or two or more contiguous nucleotides, in the sense or antisense ribonucleotide sequence which is not basepaired in the dsRNA region and which does not have a mismatched nucleotide at the corresponding position in the complementary sequence in the dsRNA region. The dsRNA region of the RNA molecule may comprise a sequence of more than 2 or 3 nucleotides within the sense or antisense sequence, or both, which loops out from the dsRNA region when the dsRNA structure forms. The sequence which loops out may itself form some internal basepairing, for example it may itself form a stem-loop structure. In an embodiment of each of the above aspects, the RNA molecule has none, or one, or two or more bulges in a double-stranded region. In this context, a bulge is a nucleotide, or two or more contiguous nucleotides, in the sense or antisense ribonucleotide sequence which is not basepaired in the dsRNA region and which does not have a mismatched nucleotide at the corresponding position in the complementary sequence in the dsRNA region. The dsRNA region of the RNA molecule may comprise a sequence of more than 2 or 3 nucleotides within the sense or antisense sequence, or both, which loops out from the dsRNA region when the dsRNA structure forms. The sequence which loops out may itself form some internal basepairing, for example it may itself form a stem-loop structure. In an embodiment of each of the above aspects, the RNA molecule has three, four or more loops. In a preferred embodiment, the RNA molecule has only two loops. In an embodiment, the first double-stranded region, or the first and second dsRNA region, or every dsRNA region, of the RNA molecule comprises one, or two, or more nucleotides which are not basepaired in the double-stranded region, or independently up to 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 10% of the nucleotides in the double- stranded region which are not basepaired. In an embodiment of each of the above aspects, about 12%, about 15%, about 18%, about 21%, about 24%, or between about 15% and about 30%, or preferably between about 16% and about 25%, of the ribonucleotides of the sense ribonucleotide sequence and its corresponding antisense ribonucleotide sequence, in total, that form a dsRNA region are either basepaired in a non-canonical basepair or are not basepaired. In a preferred embodiment, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, or 100% of the non-canonical basepairs in a dsRNA region, or in all dsRNA regions in the RNA molecule, are G:U basepairs. The G nucleotide in each G:U basepair may independently be in the sense ribonucleotide sequence or preferably in the antisense ribonucleotide sequence. Regarding the G nucleotides in the G:U basepairs of a dsRNA region, preferably at least 50% are in the antisense ribonucleotide sequence, more preferably at least 60% or 70%, even more preferably at least 80% or 90%, and most preferably at least 95% of them are in the antisense ribonucleotide sequence in the dsRNA region. This feature may apply independently to one or more or all of the dsRNA regions in the RNA molecule. In an embodiment, less than 25%, less than 20%, less than 15%, less than 10%, preferably less than 5%, more preferably less than 1% or most preferably none, of the ribonucleotides in the dsRNA region, or in all of the dsRNA regions in the RNA molecule in total, are not basepaired. In a preferred embodiment, every one in four to every one in six ribonucleotides in the dsRNA region, or in the dsRNA regions in total, form a non-canonical basepair or are not basepaired within the RNA molecule. In a preferred embodiment, the dsRNA region, or in the dsRNA regions in total, do not comprise 10 or 9 or preferably 8 contiguous canonical basepairs. In an alternative embodiment, the dsRNA region comprises at least 8 contiguous canonical basepairs, for example 8 to 12 or 8 to 14 or § to 10 contiguous canonical basepairs. In a preferred embodiment, all of the ribonucleotides in the dsRNA region, or in all dsRNA regions in the RNA molecule, are base-paired with a canonical basepair or a non-canonical basepair. In an embodiment, one or more ribonucleotides of the sense ribonucleotide sequence or one or more ribonucleotides of the antisense ribonucleotide sequence, or both, are not basepaired. In an embodiment, one or more ribonucleotides of each sense ribonucleotide sequence and one or more ribonucleotides of each antisense ribonucleotide sequence are not basepaired in the RNA molecule of the invention. In an embodiment, one or more or all of the antisense ribonucleotide sequences of the RNA molecule is less than 100% identical, or between about 80% and 99.9% identical, or between about 90% and 98% identical, or between about 95% and 98% identical, preferably between 98% and 99.9% identical, in sequence to the complement of a region of the target RNA molecule or to two such regions, which may or may not be contiguous in the target RNA molecule. In a preferred embodiment, one or more of the antisense RNA sequences is 100% identical in sequence to a region of the complement of the target RNA molecule, for example to a region comprising 21, 23, 25, 27, 30, or 32 contiguous nucleotides. In an embodiment, the sense or antisense ribonucleotide sequence, preferably both, is at least 40, at least 50, at least about 100, at least about 200, at least about 300, at least about 400, at least about 500, at least about 600, at least about 700, at least about 800, at least about 900, at least about 1,000, or about 100 to about 1,000, contiguous nucleotides in length. The lengths of at least 100 nucleotides are preferred when using the RNA molecule in plant cells. In an embodiment, the number of ribonucleotides in the sense ribonucleotide sequence is between about 90% and about 110%, preferably between 95% and 105%, more preferably between 98% and 102%, even more preferably between 99% and 101%, of the number of ribonucleotides in the corresponding antisense ribonucleotide sequence to which it hybridises. In a most preferred embodiment, the number of ribonucleotides in the sense ribonucleotide sequence is the same as the number of ribonucleotides in the corresponding antisense ribonucleotide sequence. These features can be applied to each dsRNA region in the RNA molecule. The overall length of the RNA molecule of the invention, produced as a single strand of RNA, after splicing out of any introns but before any processing of the RNA molecule by Dicer enzymes or other RNAses, is typically between 50 and 2000 ribonucleotides, preferably between 60 or 70 and 2000 ribonucleotides, more preferably between 80 or 90 and 2000 ribonucleotides, even more preferably between 100 or 110 and 2000 ribonucleotides. In preferred embodiments, the minimum length of the RNA molecule is 120, 130, 140, 150, 160, 180, or 200 nucleotides, and the maximum length is 400, 500, 600, 700, 800, 900, 1000, 1200, 1400, 1500 or 2000 ribonucleotides. Each combination of these mentioned minimum and maximum lengths is contemplated. Production of RNA molecules of such lengths by transcription in vitro or in cells such as bacterial or other microbial cells, preferably S. cerevisiae cells, or in the eukaryotic cell where the target RNA molecule is to be down-regulated, is readily achieved. In a further aspect, the present invention provides a chimeric ribonucleic acid (RNA) molecule, comprising a double-stranded RNA (dsRNA) region which comprises a sense ribonucleotide sequence and an antisense ribonucleotide sequence which are capable of hybridising to each other to form the dsRNA region, wherein i) the sense ribonucleotide sequence consists of, covalently linked in 5° to 3’ order, a first 5° ribonucleotide, a first RNA sequence and a first 3’ ribonucleotide, ii) the antisense ribonucleotide sequence consists of, covalently linked in 5° to 3’ order, a second 5° ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, iii) the first 5° ribonucleotide basepairs with the second 3’ ribonucleotide to form a terminal basepair of the dsRNA region, iv) the second 5’ ribonucleotide basepairs with the first 3’ ribonucleotide to form a terminal basepair of the dsRNA region, v) between about 5% and about 40% of the ribonucleotides of the sense ribonucleotide sequence and the antisense ribonucleotide sequence, in total, are either basepaired in a non-canonical basepair or are not basepaired, vi) the dsRNA region does not comprise 20 contiguous canonical basepairs, vii) the RNA molecule is capable of being processed in a plant cell or in vitro whereby the antisense ribonucleotide sequence is cleaved to produce short antisense RNA (asRNA) molecules of 20-24 ribonucleotides in length, viii) the RNA molecule or at least some of the asRNA molecules, or both, are capable of reducing the expression or activity of a target RNA molecule which modulates the timing of plant flowering, and ix) the RNA molecule is capable of being made enzymatically by transcription in vitro or in a cell, or both. In another aspect, the present invention provides a chimeric RNA molecule comprising a first RNA component and a second RNA component which is covalently linked to the first RNA component, wherein the first RNA component comprises a first double-stranded RNA (dsRNA) region, which comprises a first sense ribonucleotide sequence and a first antisense ribonucleotide sequence which are capable of hybridising to each other to form the first dsRNA region, and a first intervening ribonucleotide sequence of at least 4 nucleotides which covalently links the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence, wherein the second RNA component comprises a second sense ribonucleotide sequence, a second antisense ribonucleotide sequence and a second intervening ribonucleotide sequence of at least 4 ribonucleotides which covalently links the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence, wherein the second sense ribonucleotide sequence hybridises with the second antisense ribonucleotide sequence in the RNA molecule, wherein in the first RNA component, i) the first sense ribonucleotide sequence consists of at least 20 contiguous ribonucleotides covalently linked, in 5° to 3’ order, a first 5’ ribonucleotide, a first RNA sequence and a first 3’ ribonucleotide, ii) the first antisense ribonucleotide sequence consists of at least 20 contiguous ribonucleotides covalently linked, in 5° to 3” order, a second 5’ ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, iii) the first 5° ribonucleotide basepairs with the second 3’ ribonucleotide, iv) the second 5’ ribonucleotide basepairs with the first 3’ ribonucleotide, v) between 5% and 40% of the ribonucleotides of the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence, in total, are either basepaired in a non-canonical basepair or are not basepaired, and vi) the first dsRNA region does not comprise 20 contiguous canonical basepairs, wherein the chimeric RNA molecule is capable of being processed in a plant cell or in vitro whereby the first antisense ribonucleotide sequence is cleaved to produce short antisense RNA (asRNA) molecules of 20-24 ribonucleotides in length, and wherein (a) the chimeric RNA molecule or at least some of the asRNA molecules, or both, are capable of reducing the expression or activity of a target RNA molecule which modulates the timing of plant flowering, or (b) the first antisense ribonucleotide sequence comprises a sequence of at least 20 contiguous ribonucleotides which is at least 50% identical in sequence, preferably at least 90% or 100% identical in sequence, to a region of the complement of the target RNA molecule, or (¢) both (a) and (b). In an embodiment where the chimeric RNA molecule has a first RNA component, the first 5° ribonucleotide and first 3’ ribonucleotide of the first RNA component basepair to each other. That basepair is defined herein as the terminal basepair of the dsRNA region formed by self-hybridisation of the first RNA component. In the embodiment where the first sense ribonucleotide sequence is linked covalently to the first 5’ ribonucleotide without any intervening nucleotides and the first antisense ribonucleotide sequence is linked covalently to the first 3’ ribonucleotide without any intervening nucleotides, the first 5° ribonucleotide is directly linked to one of the sense sequence and antisense sequence and the first 3” ribonucleotide is directly linked to the other of the sense sequence and antisense sequence. In embodiments of the above aspects, the RNA molecule comprises one or more or all of (i) a linking ribonucleotide sequence which covalently links the first and second RNA components, (ii) a 5° extension sequence and (iii) a 3’ extension sequence, wherein the 5’ extension sequence, if present, consists of a sequence of ribonucleotides which is covalently linked to the first RNA component or to the second RNA component, and wherein the 3’ extension sequence, if present, consists of a sequence of ribonucleotides which is covalently linked to the second RNA component or to the first RNA component, respectively. In an embodiment, the first RNA component and the second RNA component are covalently linked via a linking ribonucleotide sequence. In an alternative embodiment, the first RNA component and the second RNA component are directly linked, without any linking ribonucleotide sequence present. In preferred embodiments of the above aspects, the RNA molecule is capable of being made enzymatically by transcription in vitro or in a cell, or both. In an embodiment, an RNA molecule of the present invention is expressed in a plant cell i.e. produced in the cell by transcription from one or more nucleic acids encoding the RNA molecule. The one or more nucleic acids encoding the RNA molecule is preferably a DNA molecule, which may be present on a vector in the cell or integrated into the genome of the cell, either the nuclear genome of the cell or in the plastid DNA of the cell. The one or more nucleic acids encoding the RNA molecule may also be an RNA molecule such as a viral vector. In a further aspect, the present invention provides an isolated and / or exogenous polynucleotide encoding an RNA molecule of the invention, or a chimeric RNA molecule of the invention. In an embodiment, the polynucleotide is a DNA construct. In an embodiment, the polynucleotide is operably linked to a promoter capable of directly expression of the RNA molecule in a plant cell. Examples of such promoters include, but are not limited to an RNA polymerase promoter such as an RNA polymerase III promoter, an RNA polymerase II promoter, or a promoter which functions in vitro. In an embodiment, the polynucleotide encodes an RNA precursor molecule comprising an intron in at least one loop sequence which is capable of being spliced out during transcription of the polynucleotide in a plant cell or in vitro. In an embodiment, the polynucleotide is a chimeric DNA which comprises in order, a promoter capable of initiating transcription of the RNA molecule in a host cell, operably linked to a DNA sequence which encodes the RNA molecule, preferably a hpRNA, and a transcription termination and / or polyadenylation region. In a preferred embodiment, the RNA molecule comprises a hairpin RNA structure which comprises a sense ribonucleotide sequence, a loop sequence and an antisense ribonucleotide sequence, more preferably wherein the sense and antisense ribonucleotide sequences basepair to form a dsRNA region wherein between about 5% and about 40% of the ribonucleotides in the dsRNA region are basepaired in non-canonical basepairs, preferably G:U basepairs. In an embodiment, polynucleotides of the invention comprise a nucleotide sequence set forth in SEQ ID NO:150 or a nucleotide sequence 95% identical thereto. In an embodiment, polynucleotides of the invention comprise a nucleotide sequence set forth in SEQ ID NO:150. Also provided is a vector comprising a polynucleotide of the invention. In an embodiment, the vector is a viral vector. In an embodiment, the vector is a plasmid vector such as a binary vector suitable for use with Agrobacterium tumefaciens. In an embodiment where the polynucleotide or vector of the invention is in a plant host cell, the promoter region of the polynucleotide or vector, which is operably linked to the region which encodes an RNA molecule of the invention, has a lower level of methylation when compared to the promoter of a corresponding polynucleotide or vector encoding an RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs. In an embodiment, the lower level of methylation is less than 50%, less than 40%, less than 30% or less than 20%, when compared to the promoter of the corresponding polynucleotide or vector. In an embodiment, the host cell comprises at least two copies of the polynucleotide or vector encoding an RNA molecule of the invention. In this embodiment: i) the level of reduction in the expression and / or activity of the target RNA molecule in the plant cell is at least the same relative to a corresponding plant cell having a single copy of the polynucleotide or vector, and / or ii) the level of reduction in the expression and / or activity of the target RNA molecule in the plant cell is lower when compared to a corresponding cell comprising an RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs. In another aspect, the present invention provides a host cell comprising one or more or all of an RNA molecule of the invention, a chimeric RNA molecule of the invention, small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, a polynucleotide of the invention, or a vector of the invention. The host cell may be a bacterial cell such as E. coli, a fungal cell such as a yeast cell, for example, S. cerevisiae, or a eukaryotic cell sush as a plant cell. In an embodiment, the promoter is heterologous relative to the polynucleotide. The polynucleotide encoding the RNA molecule may be a chimeric or recombinant polynucleotide, or an isolated and / or exogenous polynucleotide. In an embodiment, the promoter can function in vitro, for example a bacteriophage promoter such as a T7 RNA polymerase promoter or SP6 RNA polymerase promoter. In an embodiment, the promoter is an RNA polymerase III promoter such as a U6 promoter or an Hl promoter. In an embodiment, the promoter is an RNA polymerase II promoter, which may be a constitutive promoter, a tissue-specific promoter, a developmentally regulated promoter or an inducible promoter. In an embodiment, the polynucleotide encodes an RNA precursor molecule comprising an intron in at least one loop sequence which is capable of being spliced out during or after transcription of the polynucleotide in a host cell. In an embodiment, the host cell is a plant cell. In an embodiment, the promoter region of the polynucleotide has a lower level of methylation, such as less than about 50%, less than about 40%, less than about 30% or less than about 20%, when compared to the promoter of a corresponding polynucleotide encoding an RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs. In an embodiment, the host cell is a plant cell comprising the chimeric RNA molecule or small RNA molecules produced by processing of the chimeric RNA molecule, or both, wherein the chimeric RNA molecule comprises, in 5° to 3’ order, the first sense ribonucleotide sequence, the first linking ribonucleotide sequence which comprises a loop sequence, and the first antisense ribonucleotide sequence. In an embodiment, the plant cell may be from Arabidopsis, corn, canola, cotton, soybean, alfalfa, lettuce, wheat, barley, rice, legume, Medicago truncatula, sugarbeet or rye. In an embodiment, the plant cell may be from Arabidopsis, com, canola, cotton, soybean, wheat, barley, rice, legume, Medicago truncatula, sugarbeet or rye. In an embodiment, the host cell comprises at least two copies of the polynucleotide, and wherein i) the level of reduction in the expression or activity of the target RNA molecule in a plant cell is at least the same when compared to if the cell had a single copy of the polynucleotide, and / or ii) the level of reduction in the expression or activity of the target RNA molecule in a plant cell is lower when compared to a corresponding cell comprising an RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs. In an embodiment, the cell encodes and / or comprises the chimeric RNA molecule of the invention and the level of sense ribonucleotide sequence in the cell is less than 50 to 999% the level of the antisense ribonucleotide. In an embodiment, the RNA molecule is expressed in a eukaryotic cell i.e. produced by transcription in the cell. In these embodiments, a greater proportion of dsRNA molecules are formed by processing of the RNA molecule that are 22 and / or 20 ribonucleotides in length when compared to processing of an analogous RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs. That is, the RNA molecules of these embodiments are more readily processed to provide 22- and / or 20-ribonucleotide short antisense RNAs than the analogous RNA molecule whose dsRNA region is fully basepaired with canonical basepairs, as a proportion of the total number of 20-24 nucleotide asRNAs produced from the RNA molecule. Expressed differently, a lesser proportion of dsRNA molecules are formed by processing of the RNA molecule that are 23 and / or 21 ribonucleotides in length when compared to processing of an analogous RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs. That is, the RNA molecules of these embodiments are less readily processed to provide 23- and / or 21-ribonucleotide short antisense RNAs than the analogous RNA molecule whose dsRNA region is fully basepaired with canonical basepairs, as a proportion of the total number of 20-24 nucleotide asRNAs produced from the RNA molecule. Preferably, at least 50% of the RNA transcripts produced in the cell by transcription from the genetic construct are not processed by Dicer. In an embodiment, when the RNA molecule is expressed in a eukaryotic cell i.e. produced by transcription in the cell, a greater proportion of the short antisense RNA molecules that are formed by processing of the RNA molecule have more than one phosphate covalently attached at the 5’ terminus when compared to processing of an analogous RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs. That is, a greater proportion of the short antisense RNA molecules have an altered charge which can be observed as a mobility shift of the molecules in gel electrophoresis experiments. In a further aspect, the present invention provides a plant comprising one or more or all of an RNA molecule of the invention, a chimeric RNA molecule of the invention, small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, a polynucleotide of the invention, a vector of the invention, or a host cell of the invention which is a plant cell. In an embodiment, the plant is transgenic insofar as it comprises a polynucleotide of the invention. In an embodiment, the polynucleotide is stably integrated into the genome of the plant. The invention also includes plant parts, and products obtained therefrom, comprising the RNA molecule or small RNA molecules (20-24nt in length) produced by processing of the chimeric RNA molecule, or both, and / or the polynucleotide or vector of the invention, for example to seeds, crops, harvested products and post-harvest products produced therefrom. In a further aspect, the present invention provides a method of producing an RNA molecule of the invention, or a chimeric RNA molecule of the invention, the method comprising expressing the polynucleotide of the invention in a host cell or cell- free expression system. In an embodiment, the method further comprises at least partially purifying the RNA molecule. In another aspect, the present invention provides a method of producing the plant of the invention, the method comprising introducing the polynucleotide of the invention into a plant cell so that it is stably integrated into the genome of the cell, and generating the plant from the cell. In another aspect, the present invention provides a method of producing a cell or plant, the method comprising introducing a polynucleotide or vector or RNA molecule of the invention into a plant cell, preferably so that the polynucleotide or vector or part thereof encoding the RNA molecule is stably integrated into the genome of the plant cell. In an embodiment, the plant is generated from the cell or a progeny cell, for example by regenerating a transgenic plant and optionally producing progeny plants therefrom. In an embodiment, the plant is generated by introducing the cell or one or more progeny cells into the plant. Alternatively to the stable integration of the polynucleotide or vector into the genome of the plant cell, the polynucleotide or vector may be introduced into the cell without integration of the polynucleotide or vector into the genome, for example to produce the RNA molecule transiently in the plant cell or plant. In an embodiment, the plant, is resistant to a pest or pathogen, e.g. a plant pest or pathogen, preferably an insect pest or fungal pathogen. In an embodiment, the method comprises a step of testing one or more plants, comprising the polynucleotide or vector or RNA molecule of the disclosure for modulation of flowering. The plants that are tested may be progeny from the plant, into which the polynucleotide or vector or RNA molecule of the disclosure was first introduced, and therefore the method may comprise a step of obtaining such progeny. The method may further comprise a step of identifying and / or selecting the plant with desired time to flowering such as early flowering. For example, multiple plants, which each comprise the polynucleotide or vector or RNA molecule of the invention may be tested to identify those with desired time to flowering, and progeny obtained from the identified plant(s). In a further aspect, the present invention provides an extract of a host cell of the invention, wherein the extract comprises the RNA molecule of the invention, a chimeric RNA molecule of the invention, small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, or both, and / or the polynucleotide of the invention. In a further aspect, the present invention provides a composition comprising one or more of an RNA molecule of the invention, a chimeric RNA molecule of the invention, small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, a polynucleotide of the invention, a vector of the invention, a host cell of the invention, or an extract of the invention, and one or more suitable carriers. In one embodiment, the composition is suitable for application to a field, e.g. as topical spray. In an embodiment, the field comprises plants. In an embodiment, the composition is suitable for application to a crop, for example by spraying on crop plants in a field. In a further embodiment, the composition further comprises at least one compound which enhances the stability of the RNA molecule, chimeric RNA molecule or polynucleotide and / or which assists in the RNA molecule, chimeric RNA molecule or polynucleotide being taken up by a cell of a plant. In an embodiment, the compound is a transfection promoting agent. In an aspect, the present invention provides a method for down-regulating the level and / or activity of a target RNA molecule which modulates plant flowering in a plant, the method comprising delivering to the plant one or more of an RNA molecule of the invention, a chimeric RNA molecule of the invention, small RNA molecules (20- 24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, a polynucleotide of the invention, a vector of the invention, a host cell of the invention, an extract of the invention, or a composition of the invention. In this context, delivering may be via contacting, exposing, transforming or otherwise introducing an RNA molecule or chimeric RNA molecule disclosed herein or a mixture thereof, or small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule or the polynucleotide or vector of the invention to the plant cell or plant. The introduction may be enhanced by use of an agent that increases the uptake of the RNA molecule(s), polynucleotides or vectors of the invention, for example with the aid of transfection promoting agents, DNA- or RNA-binding polypeptides, or may be done without adding such agents, for example by planting seed which is transgenic for a polynucleotide or vector of the invention and allowing the seed to grow into a transgenic plant which expresses the RNA molecules of the invention. In an embodiment, the target RNA molecule encodes a protein. In an embodiment, the method reduces the level and / or activity of more than one target RNA molecule, the target RNA molecules being different, for example two or more target RNAs are reduced in level and / or activity which are related in sequence such as from a gene family. Thus, in an embodiment, the chimeric RNA molecule or small RNA molecules produced by processing of the chimeric RNA molecule, or both, are contacted with the cell or organism, preferably a plant cell or plant by topical application to the cell or organism, or provided in a feed for the organism. In an embodiment, the target RNA molecule encodes a protein. Alternatively, one or more of the target RNAs do not encode a protein, such as a rRNA, tRNA, snoRNA or miRNA. In an embodiment, the chimeric RNA molecule, or small RNA molecules produced by processing of the chimeric RNA molecule, or both, are contacted with the cell or plant by topical application to the cell or plant. In another embodiment, the present disclosure encompasses a method of promoting flowering time of a plant, the method comprising expressing a polynucleotide heterologous to said plant, wherein said polynucleotide heterologous to said plant is a polynucleotide of the invention such as an RNA molecule of the invention, wherein expression of said polynucleotide in said plant directs early flowering. The present inventors have surprisingly found that RNA can be directly applied to a plant or seed to influence future flowering time. Thus, in a further aspect the present invention provides a method of modulating the flowering time of a plant, or a plant produced from a seed, the method comprising contacting the plant or seed with a composition comprising an RNA molecule which comprises at least one double stranded RNA region, and / or a polynucleotide(s) encoding the RNA molecule, wherein the at least one double stranded RNA region comprises an antisense ribonucleotide sequence which is capable of hybridising to a region of a target RNA molecule which modulates the timing of plant flowering. In an embodiment, the composition is an aqueous composition. In an embodiment, the composition comprises at least one compound which enhances the stability of the RNA molecule and / or which assists in the RNA molecule being taken up by a cell of a plant. In an embodiment, the compound is a transfection promoting agent. In an embodiment, the method comprises soaking the seed in the composition. In an alternate embodiment, the plant is a seedling, and the method comprises soaking at least a part of the seedling in the composition. In an embodiment, at least a part, or all, of the cotyledon(s) and / or the hypocotyl are soaked in the composition. In an embodiment, the plant is in a field and the method comprising spraying the composition on at least a part of the plant. The RNA molecule can have any suitable structure for gene silencing. Examples include, but are not limited to, hairpin RNA, a microRNA, a siRNA or an ledRNA. The RNA molecule of the above aspect can be a chimeric RNA molecule such as described herein. The nature in which flowering time is modulated will depend on the taget RNA molecule. In one embodiment, the plant has an early flowering time when compared to a control plant that has not been applied with the composition. In an alternate embodiment, the plant has a late flowering time when compared to a control plant that has not been applied with the composition. Examples of target RNA molecules to be targeted to induce early or late falowering are discussed herein. In an embodiment, the RNA molecule is complexed with a non-RNA molecule such as DNA, a protein or a polymer. In an embodiment, the complex comprises the RNA molecule conjugated to the non-RNA molecule such as by a covalent bond. In an embodiment, the composition is topically applied to the plant or seed. In an embodiment, the polynucleotide is present in the composition in a cell and / or a vector. In another aspect, the present invention provideds a kit comprising one or more of an RNA molecule of the invention, a chimeric RNA molecule of the invention, a polynucleotide of the invention, a vector of the invention, a host cell of the invention, an extract of the invention, or a composition of the invention. The kit may further comprise instructions for use of the kit. ‘Whilst more widely used in transgenic expression systems, as discussed herein there are also applications of dsRNA technology which rely on the need for the large scale production of dsRNA molecules, such as spraying a crop to modulate flowering. The present inventors have identified S. cerevisiae as a suitable organism to use in large scale production processes because dsRNA molecules expressed therein are not cleaved. Thus, in a further aspect, the present invention provides a process for producing dsRNA molecules, the process comprising a) culturing §. cerevisiae expressing one or more polynucleotides encoding one or more dsRNA molecules, and b) harvesting the S. cerevisiae producing the dsRNA molecules, or the dsRNA molecules from the S. cerevisiae, wherein the S. cerevisiae are cultured in a volume of at least 1 litre. The dsRNA can have any structure, such as an hairpin RNA (for example shRNA), a miRNA or a dsRNA of the invention. In an embodiment, the S. cerevisiae are cultured in a volume of at least 10 litres, at least 100 litres, at least 1,000 litres, at least 10,000 litres or at least 100,000 litres. In an embodiment, the process produces at least 0.1, at least 0.5 or at least 1 g / litre of an RNA molecule of the invention. The S. cerevisiae produced using the process, or dsRNA molecules isolated therefrom (either in a purified or partially purified (such as an extract) state) can be used in methods described herein such as, but not limited to, a method for reducing or down-regulating the level and / or activity of a target RNA molecule in a cell or plant. Any embodiment herein shall be taken to apply mutatis mutandis to any other embodiment unless specifically stated otherwise. The present invention is not to be limited in scope by the specific embodiments described herein, which are intended for the purpose of exemplification only. Functionally-equivalent products, compositions and methods are clearly within the scope of the invention, as described herein. Throughout this specification, unless specifically stated otherwise or the context requires otherwise, reference to a single step, composition of matter, group of steps or group of compositions of matter shall be taken to encompass one and a plurality (i.e. one or more) of those steps, compositions of matter, groups of steps or group of compositions of matter. The invention is hereinafter described by way of the following non-limiting Examples and with reference to the accompanying figures. BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS Figure 1. Schematic designs of two ledRNA molecules. (A) This ledRNA molecule comprises a sense sequence which can be considered to be two adjacent sense sequences, covalently linked without an intervening spacer sequence and having identity to the target RNA, an antisense sequence which is complementary to the sense sequence and which is divided into two regions, a 5’ region and a 3’ region, and two loops that separate the sense from the antisense sequences. (B) This ledRNA molecule comprises an antisense sequence which can be considered to be two adjacent antisense sequences, covalently linked without an intervening spacer sequence and having identity to the complement of a target RNA, a sense sequence which is complementary to the antisense sequence and which is divided into two regions, and two loops that separate the sense from the antisense sequences. The RNA molecule produced by transcription, for example by in vitro transcription from a promoter such as a T7 or Sp6 promoter, self-anneals by basepairing between the complementary sense and antisense sequences to form a double-stranded region with a loop at each end and having a “nick” in either the antisense or sense sequence. Additional sequences may be linked to the 5° and / or 3’ ends as 5’- or 3’-extensions. Figure 2. ledRNA is more efficient in forming dsRNA than sense / antisense annealing or hairpin RNA. Schematic representations of three forms of double-stranded RNA molecules are shown: A, conventional dsRNA formed by annealing of two separate strands; B, a hairpin RNA having a 5’- and a 3’-extension; and C, ledRNA molecule. The lower panel shows a photograph after gel electrophoresis of the RNA transcripts for the three types of RNA molecules targeting either a GUS gene or a GFP gene. Figure 3. Northern blot hybridization of treated (A and B) and untreated distal (C and D) tissues shows that ledRNA is more stable than dsRNA and spread through tobacco leaf tissue. In the distal tissues (C and D, top panel) the dsRNA signal could not be detected, in contrast to strong ledRNA signals. Figure 4. 1edRNA treatment induced downregulation of GUS in both the treated area (1) and the untreated area above (3). Figure 5. ledRNA induces silencing of the FAD2.1 gene in N. benthamiana leaves. Figure 6. Northern blot hybridization confirms strong downregulation of FAD2.1 mRNA by treatment with ledFAD2.1 at 6 and 24 hours. Figure 7. Alignment of the nucleotide sequences of a region of the GUS target gene (SEQ ID NO:14) and the sense sequence of the hpGUS[G:U] construct (nucleotides 9 to 208 of SEQ ID NO:11). 52 cytidine (C) nucleotides were substituted with thymidine (T) nucleotides. Conserved nucleotides are asterisked, substituted C’s are not asterisked. Figure 8. Alignment of the nucleotide sequences of a region of the GUS target gene (SEQ ID NO:14) and the sense sequence of the hpGUS[1:4] construct (nucleotides 9 to 208 of SEQ ID NO:12). Every 4th nucleotide in hpGUS[1:4] was substituted relative to the corresponding wild-type sense sequence, whereby for every 4th nucleotide, C was changed to G, G was changed to C, A was changed to T, and T was changed to A. Conserved nucleotides are asterisked, substituted G’s and C’s are not asterisked, substituted A’s and T’s are shown with semi-colons. Figure 9. Alignment of the nucleotide sequences of a region of the GUS target gene (SEQ ID NO:14) and the sense sequence of the hpGUS[2:10] construct (nucleotides 9 to 208 of SEQ ID NO:13). Every 9th and 10th nucleotide in each block of 10 nucleotides in hpGUS[2:10] was substituted relative to the corresponding wild-type sense sequence, whereby for every 9th and 10th nucleotide, C was changed to G, G was changed to C, A was changed to T and T was changed to A. Conserved nucleotides are asterisked, substituted G’s and C’s are not asterisked, substituted A’s and T’s are shown with semi-colons. Figure 10. Schematic diagram showing structures of the genetic constructs encoding modified hairpin RNAs targeting GUS mRNA. Figure 11. Schematic diagram of vector pWBPPGH used to transform tobacco plants, providing a GUS target gene. The T-DNA extends from the right border (RB) to the left border (LB) of the vector. The selectable marker gene on the T-DNA is the 35S- HPT-tm1’ gene encoding hygromycin resistance. Figure 12. GUS activity in plants transformed with constructs encoding modified hairpin RNAs for reducing expression of a GUS target gene. No hp: control PPGH11 and PPGH24 plants with no hpGUS constructs. The number of plants showing less than 10% GUS activity compared to the corresponding control PPGH11 or PPGH24 plants and the percentage of such plants relative to the number of plants tested are given in brackets. Figure 13. (A) Average GUS activity of all transgenic plants: 59 plants for hpGUS[wt], 74 for hpGUS[G:U], 33 for hpGUS[1:4] and 41 for hpGUS[2:10]. (B) Average GUS activity of all silenced plants (32 for hpGUS[wt], 71 for hpGUS[G:U], 33 for hpGUS[1:4] and 28 for hpGUS[2:10]. Figure 14. GUS activity of transgenic progeny plants containing hpGUS[wt], hpGUS[G:U] or hpGUS[ 1:4]. Figure 15. Autoradiograph of a Southern blot of DNA from 16 plants transformed with the hpGUS[G:U] construct. DNAs were digested with HindIII prior to gel electrophoresis and probed with an OCS-T probe. Lane 1: size markers (HindIII- digested lambda DNA); Lanes 2 and 3, DNA from parental plants PPGHI11 and PPGH24; Lanes 4-19: DNAs from 16 different transgenic plants. Figure 16. Autoradiogram of a Northern blot hybridisation experiment to detect sense (upper panel) and antisense (lower panel) sSRNAs derived from hairpin RNAs expressed in transgenic tobacco plants. Lanes 1 and 2 contained RNA obtained from the parental plants PPGH11 and PPGH24 lacking the hpGUS constructs. Lanes 3-11 contained RNA from hpGUS[wt] plants and lanes 12-20 contained RNA from hpGUS[G:U] plants. Figure 17. Autoradiograph of a Northern blot hybridisation to detect antisense SRNAs from transgenic plants. Lanes 1-10 were from hpGUS[wt] plants, lanes 11-19 were from hpGUS[G:U] plants. The antisense sSRNAs have mobility corresponding to 20- 24nt in length. The blot was reprobed with antisense to U6 RNA as a lane-loading control. Figure 18. Autoradiograph of a repeat Northern blot hybridisation to detect antisense sRNAs from transgenic plants Figure 19. DNA methylation analysis of the junction region of the 35S promoter and sense GUS region in hpGUS constructs in transgenic plants. The junction fragments were PCR-amplified either with (+) or without (-) prior treatment of plant DNA with McrBC enzyme. Figure 20. DNA methylation analysis of the 35S promoter region in hpGUS constructs in transgenic plants. The 35S fragments were PCR-amplified either with (+) or without (-) prior treatment of plant DNA with McrBC enzyme. Figure 21. Size distribution and abundance of processed RNA. (A) EIN2 constructs. (B) GUS constructs. Figure 22. Alignment of the sense sequence (upper sequence, nucleotides 17 to 216 of SEQ ID NO:22) of the hpEIN2[G:U] construct and the nucleotide sequence (lower sequence, SEQ ID NO:27) of a region of the cDNA corresponding to the A. thaliana EIN2 target gene. The sense sequence was made by replacing 43 cytidine (C) nucleotides in the wild-type sequence with thymidine (T) nucleotides. Conserved nucleotides are asterisked, substituted C’s are not asterisked. Figure 23. Alignment of the sense sequence (upper sequence, nucleotides 13 to 212 of SEQ ID NO:24) of the hpCHS[G:U] construct with the nucleotide sequence of a region of the cDNA corresponding to the A. thaliana CHS target gene (SEQ ID NO:28, lower sequence). The sense sequence was made by replacing 65 cytidine (C) nucleotides in the wild-type sequence with thymidine (T) nucleotides. Conserved nucleotides are asterisked, substituted C’s are not asterisked. Figure 24. Alignment of the antisense sequence (upper sequence, nucleotides 8 to 207 of SEQ ID NO:25) of the hpEIN2[G:U / U:G] construct and the nucleotide sequence (lower sequence, SEQ ID NO:29) of a region of the complement of the A. thaliana EIN2 target gene and the. The antisense sequence was made by replacing 49 cytidine (C) nucleotides in the wild-type sequence with thymidine (T) nucleotides. Conserved nucleotides are asterisked, substituted C’s are not asterisked. Figure 25. Alignment of the antisense sequence (upper sequence, nucleotides 13 to 212 of SEQ ID NO:26) of the hpCHS[G:U / U:G] construct and the nucleotide sequence (lower sequence, SEQ ID NO:30) of a region of the complement of the A. thaliana CHS target gene. The antisense sequence was made by replacing 49 cytidine (C) nucleotides in the wild-type sequence with thymidine (T) nucleotides. Conserved nucleotides are asterisked, substituted C’s are not asterisked. Figure 26. Schematic diagrams of the ethylene insensitive 2 (EIN2) and chalcone synthase (CHS) hpRNA constructs. 35S: CaMV 35S promoter; EIN2 and CHS regions are show either as wild-type sequence (wt) or the G:U modified sequence (G:U). The arrows indicate the orientation of the DNA fragments — right to left arrows indicate the antisense sequences. Restriction enzyme sites are also shown. Figure 27. Hypocotyl lengths of transgenic A. thaliana seedlings in the EIN2 assay, containing either the hpEIN2[wt] or hpEIN2[G:U] Figure 28. qRT-PCR for CHS mRNA in transgenic A. thaliana transgenic for the hpCHS[wt] or hpCHS[G:U] constructs, normalised to the levels of Actin2 RNA. Col-0 is the wild-type (nontransgenic) A. thaliana. Figure 29. Autoradiograph of Northern blot hybridisation of RNA from plants transformed with hpEIN2[wt] or hpEIN2[G:U]. Upper panel shows the hypocotyl length for the lines. The autoradiograph shows Northern blot probed with an EIN2 sense probe to detect antisense SRNAs. The same blot was re-probed with a U6 RNA probe as a loading control (U6 RNA). Figure 30. DNA methylation analysis of 35S promoter and 35S-sense EIN2 sequences in genomic DNA of transgenic A. thaliana plants. Figure 31. Levels of DNA methylation in the promoter and 5’ region of hairpin RNA constructs. Figure 32. 35S promoter in the least methylated lines of the hpEIN2[wt] population still shows significant methylation. Figure 33. 35S promoter in the G:U hpEIN2 lines shows only weak methylation (<10%). Figure 34. 1edRNA and hpRNA with G:U gene silencing in CHO and Vero cells at 72 hrs. Figure 35. Dumbbell plasmids tested in Hela cells at 48 hrs. Figure 36. Examples of possible modifications of dsRNA molecules. Figure 37. Reduced aphid performance following feeding from artificial diet supplemented with ledRNA for down-regulating expression of the MpC002 or MpRack-1 genes in green peach aphid. Upper panel (A): the average number of nymphs per adult aphid after a ten day period with 100 ul of 50ng / ul ledRNA. Lower panel (B): percentage of aphids surviving over a five day time course after feeding on 100 pl containing 200ng / ul ledRNA of MpC002, MpRack-1 or the control ledGFP. Figure 38. Northern blot hybridization to detect ledGUS and hpGUS RNA using full- length sense GUS transcript as probe. “+” at the bottom indicates high GUS expression; “.” indicates low / no GUS expression i.e. strong GUS silencing. Figure 39. Northern blot hybridization to detect long hpEIN2 and ledEIN2 RNA (upper panel) and siRNAs derived from the two constructs (lower panel). Figure 40. Schematic representation of stem-loop structures of transcripts expressed from GUS hpRNA constructs. The transcripts have complementary sense and antisense sequences which basepair to form GUS sequence-specific dsRNA stems, with the indicated lengths in basepairs (bp) for the stems, and the number of nucleotides (nt) in the loops. The GFP hpRNA constructs encoded transcripts that formed a GFP-specific dsRNA stem with completely canonical basepairing (GFPhp[WT] or a dsRNA stem having about 25% of basepairs as G:U base-pairs (GFPhp[G:U], with a loop derived from a region of GUS coding sequence. The loop sequences for the GFPhp transcripts each comprised two sequences that were complementary to miR165 / miR166 and therefore provide binding sites for these miRNAs. Figure 41. Northern blot hybridisation analysis showing that transgenes encoding hpRNAs generate distinct fragments of the loop sequence when expressed in plant cells. (A) Expression of the GUS target gene (GUS) and the long hpRNA transgene GUShp1100 with a 1100 nt spacer / loop sequence. A construct encoding the cucumber mosaic virus 2b RNA silencing suppressor (CMV2b) was included to enhance transgene expression. (B) Northern blot analysis showing RNA from expression of the two short hpRNA transgenes GUShp93-1 and GUShp93-2 in stably transformed A. thaliana plants. RNA samples were either treated (+) or not treated (-) with RNAse IL Both RNA blots were hybridized with loop-specific antisense RNA probes. Figure 42, The loop of GUShp1100 accumulated to high levels in N. benthamiana cells and was resistant to RNase R digestion. Figure 43. Transgenic S. cerevisiae expressing a GUShp1100 construct showed a single RNA molecular species corresponding to the full length hairpin RNA transcript. The lower panel shows the Northern blot hybridisation of RNA samples from the transgenic S. cerevisiae. Figure 44. GUShp1100 transcript expressed in S. cerevisiae remains full-length and does not form circular loop RNA. The first four lanes used in vitro transcripts of full- length or the dsRNA stem of GUShp1100, supplemented with total RNA isolated from wild-type N. benthamiana leaves. Figure 45. hpRNA loops may be used as an effective sequence-specific repressor of miRNAs. (A) The GFPhp[G:U] construct induced strong miR165 / 166 suppression phenotypes in transgenic Arabidopsis plants. (B) Northern blot hybridization to determine the abundance of GFPhp transcript in RNA from transgenic Arabidopsis plants. (C) RT-gPCR analysis of circular RNA of the GFPhp loop. Figure 46. Treatment of wheat seedlings with ledTaVRN2 reduced the requirement of winter wheat for vernalisation prior to initiation of flowering. A) LedTaVRN2 treated seeds of winter wheat variety CSIRO W7 flowered earlier than untreated or mock treated W7. B) The earlier flowering of W7 wheat treated with ledTaVRN2 caused fewer nodes to be dedicated to leaves. Meaning more nodes were dedicated to flowers / grain. Chinese Spring is a spring type wheat that does not require vernalisation, used as a control. Figure 47. Treatment of the winter wheat variety CSIRO W7 with ledTaVRN2 induced earlier flowering compared to ledGFP, mock and no treatment controls. Early flowering parental genotypes Sunstate A (SSA) and Sunstate B (SSB) lacked a vernalisation response and were included as controls. KEY TO THE SEQUENCE LISTING SEQ ID NO:1 — Ribonucleotide sequence of GFP ledRNA. SEQ ID NO:2 - Ribonucleotide sequence of GUS ledRNA. SEQ ID NO:3 — Ribonucleotide sequence of N. benthamiana FAD2.1 ledRNA. SEQ ID NO:4 — Nucleotide sequence encoding GFP ledRNA. SEQ ID NO:5 — Nucleotide sequence encoding GUS ledRNA. SEQ ID NO:6 — Nucleotide sequence encoding N. benthamiana FAD2.1 ledRNA. SEQ ID NO:7 — Nucleotide sequence encoding GFP. SEQ ID NO:8 — Nucleotide sequence encoding GUS. SEQ ID NO:9 — Nucleotide sequence encoding N. benthamiana FAD2.1. SEQ ID NO:10 — Nucleotide sequence used to provide the GUS sense region for constructs encoding hairpin RNA molecules targeting the GUS mRNA. SEQ ID NO:11 — Nucleotide sequence used to provide the GUS sense region for the construct encoding the hairpin RNA molecule hpGUS[G:U]. SEQ ID NO:12 — Nucleotide sequence used to provide the GUS sense region for constructs encoding the hairpin RNA molecule hpGUS[ 1:4]. SEQ ID NO:13 — Nucleotide sequence used to provide the GUS sense region for constructs encoding the hairpin RNA molecule hpGUS[2:10]. SEQ ID NO:14 — Nucleotide sequence of nucleotides 781-1020 of the protein coding region of the GUS gene. SEQ ID NO:15 — Ribonucleotide sequence of the hairpin structure (including its loop) of the hpGUS[wt] RNA. SEQ ID NO:16 — Ribonucleotide of the hairpin structure (including its loop) of the hpGUS[G:U] RNA. SEQ ID NO:17 — Ribonucleotide of the hairpin structure (including its loop) of the hpGUS[1:4] RNA. SEQ ID NO:18 — Ribonucleotide of the hairpin structure (including its loop) of the hpGUS[2:10] RNA. SEQ ID NO:19 — Nucleotide sequence of the cDNA corresponding to the A. thaliana EIN2 gene, Accession No. NM_120406. SEQ ID NO:20 — Nucleotide sequence of the cDNA corresponding to A. thaliana CHS gene, Accession No. NM_121396, 1703nt. SEQ ID NO:21 — Nucleotide sequence of a DNA fragment comprising a 200nt sense sequence from the cDNA corresponding to the A. thaliana EIN2 gene flanked by restriction enzyme sites. SEQ ID NO:22 — Nucleotide sequence of a DNA fragment comprising the 200nt sense sequence of EIN2 as for SEQ ID NO:21 except that 43 C’s were replaced with T’s, used in constructing hpEIN2[G:U]. SEQ ID NO:23 - Nucleotide sequence of a DNA fragment comprising a 200nt sense sequence from the cDNA corresponding to A. thaliana CHS gene flanked by restriction enzyme sites. SEQ ID NO:24 — Nucleotide sequence of a DNA fragment comprising the 200nt sense sequence of CHS as for SEQ ID NO:23 except that 65 C’s were replaced with T's, used in constructing hpCHS[G:U]. SEQ ID NO:25 - Nucleotide sequence of a DNA fragment comprising the 200nt antisense sequence of EIN2 with 50 C’s replaced with Ts, used in constructing hpEIN2[G:U / U:G]. SEQ ID NO:26 — Nucleotide sequence of a DNA fragment comprising the 200nt antisense sequence of CHS with 49 C’s replaced with T's, used in constructing hpCHS[G:U / U:G]. SEQ ID NO:27 -- Nucleotide sequence of nucleotides 601-900 of the cDNA corresponding to the EIN2 gene from A. thaliana (Accession No. NM_120406). SEQ ID NO:28 — Nucleotide sequence of nucleotides 813-1112 of the cDNA corresponding to the CHS gene from A. thaliana (Accession No. NM_121396). SEQ ID NO:29 — Nucleotide sequence of the complement of nucleotides 652-891 of the cDNA corresponding to the EIN2 gene from A. thaliana (Accession No. NM_120406). SEQ ID NO:30 — Nucleotide sequence of the complement of nucleotides 804-1103 of the cDNA corresponding to the CHS gene from A. thaliana. SEQ ID NO:31 — FANCM 1 protein coding region of the cDNA of Arabidopsis thaliana, Accession No NM_001333162. Target region nucleotides 675-1174 (500 nucleotides) SEQ ID NO:32 — FANCM I protein coding region of a cDNA of Brassica napus. Target region nucleotides 896-1395 (500 bp) SEQ ID NO:33 — Nucleotide sequence encoding hpFANCM-At[wt] targeting the FANCM 1 protein coding region of A. thaliana. FANCM sense sequence, nucleotides 38-537; loop sequence, nucleotides 538-1306; FANCM antisense sequence, nucleotides 1307-1806. SEQ ID NO:34 — Nucleotide sequence encoding hpFANCM-At[G:U] targeting the FANCM 1 protein coding region of A. thaliana. FANCM sense sequence, nucleotides 38-537; loop sequence, nucleotides 538-1306; FANCM antisense sequence, nucleotides 1307-1806. SEQ ID NO:35 — Nucleotide sequence encoding hpFANCM-Bn[wt] targeting the FANCM I protein coding region of B. napus. FANCM sense sequence, nucleotides 34- 533; loop sequence, nucleotides 534-1300; FANCM antisense sequence, nucleotides 1301-1800. SEQ ID NO:36 - Nucleotide sequence encoding hpFANCM-Bn[G:U] targeting the FANCM I protein coding region of B. napus. FANCM sense sequence, nucleotides 34- 533; loop sequence, nucleotides 534-1300; FANCM antisense sequence, nucleotides 1301-1800. SEQ ID NO:37 — Nucleotide sequence of the protein coding region of the cDNA corresponding to the B. napus DDM1 gene; Accession No. XR_001278527. SEQ ID NO:38 - Nucleotide sequence of DNA encoding hpDDM1-Bn[wt] targeting the DDM 1 protein coding region of B. napus. SEQ ID NO:39 — Nucleotide sequence encoding hpDDM1-Bn[G:U] targeting the DDMI1 protein coding region of B. napus. DDM1 sense sequence, nucleotides 35-536; loop sequence, nucleotides 537-1304; DDM1 antisense sequence, nucleotides 1305- 1805. SEQ ID NO:40 — EGFP cDNA. SEQ ID NO:41 — Nucleotide sequence of the coding region of hpEGFP[wt], with the order antisense / loop / sense with respect to the promoter. SEQ ID NO:42 — Nucleotide sequence of the coding region of hpEGFP[G:U] which has 157 C to T substitutions in the EGFP sense sequence. SEQ ID NO:43 — Nucleotide sequence of the coding region of ledEGFP[wt] which has no C to T substitutions in the EGFP sense sequence. SEQ ID NO:44 — Nucleotide sequence of the coding region of ledEGFP[G:U] which has 162 C to T substitutions in the EGFP sense sequence. SEQ ID NO:45 — Nucleotide sequence used to provide the GUS sense region for the construct encoding the hairpin RNA molecule hpGUS[G:U] without flanking restriction enzyme sites. SEQ ID NO:46 — Nucleotide sequence used to provide the GUS sense region for constructs encoding the hairpin RNA molecule hpGUS[ 1:4] without flanking restriction enzyme sites. SEQ ID NO:47 — Nucleotide sequence used to provide the GUS sense region for constructs encoding the hairpin RNA molecule hpGUS[2:10] without flanking restriction enzyme sites. SEQ ID NO:48 — Nucleotide sequence of a DNA fragment comprising the 200nt sense sequence of EIN2 as for SEQ ID NO:21 except that 43 C’s were replaced with T’s, used in constructing hpEIN2[G:U] without flanking sequences. SEQ ID NO:49 — Nucleotide sequence of a DNA fragment comprising the 200nt sense sequence of CHS as for SEQ ID NO:23 except that 65 C’s were replaced with T’s, used in constructing hpCHS[G:U] without flanking sequences. SEQ ID NO:50 — Nucleotide sequence of a DNA fragment comprising the 200nt antisense sequence of EIN2 with 50 C’s replaced with T's, used in constructing hpEIN2[G:U / U:G] without flanking sequences SEQ ID NO:51 - Nucleotide sequence of a DNA fragment comprising the 200nt antisense sequence of CHS with 49 C’s replaced with T’s, used in constructing hpCHS[G:U / U:G] without flanking sequences. SEQ ID NO:52 — Oligonucleotide primer used for amplifying the 200 bp GUS sense sequence (GUS-WT-F) SEQ ID NO:53 — Oligonucleotide primer used for amplifying the 200 bp GUS sense sequence (GUS-WT-R) SEQ ID NO:54 -. Oligonucleotide primer (forward) used for producing the hpGUS[G:U] fragment with every C replaced with T (GUS-GU-F) SEQ ID NO:55 - Oligonucleotide primer (reverse) used for producing the hpGUS[G:U] fragment with every C replaced with T (GUS-GU-R) SEQ ID NO:56 — Oligonucleotide primer (forward) used for producing the hpGUS[1:4] fragment with every 4th nucleotide substituted (GUS-4M-F) SEQ ID NO:57 — Oligonucleotide primer (reverse) used for producing the hpGUS[1:4] fragment with every 4th nucleotide substituted (GUS-4M-R) SEQ ID NO:58 -. Oligonucleotide primer (forward) used for producing the hpGUS[2:10] fragment with every 9th and 10th nucleotide substituted (GUS-10M-F) SEQ ID NO:59 - Oligonucleotide primer (reverse) used for producing the hpGUS[2:10] fragment with every 9th and 10th nucleotide substituted (GUS-10M-R) SEQ ID NO:60 — Nucleotide sequence encoding forward primer (35S-F3) SEQ ID NO:61 — Nucleotide sequence encoding reverse primer (GUSwt-R2) SEQ ID NO:62 — Nucleotide sequence encoding forward primer (GUSgu-R2) SEQ ID NO:63 — Nucleotide sequence encoding reverse primer (GUS4m-R2) SEQ ID NO:64 — Nucleotide sequence encoding forward primer (355-F2) SEQ ID NO:65 — Nucleotide sequence encoding reverse primer (35S-R1) SEQ ID NO:66 — Oligonucleotide primer used for amplifying the wild-type 200 bp EIN2 sense sequence (EIN2wt-F) SEQ ID NO:67 — Oligonucleotide primer used for amplifying the wild-type 200 bp EIN2 sense sequence (EIN2wt-R) SEQ ID NO:68 - Oligonucleotide primer used for amplifying the wild-type 200 bp CHS sense sequence (CHSwt-F) SEQ ID NO:69 - Oligonucleotide primer used for amplifying the wild-type 200 bp CHS sense sequence (CHSwt-R) SEQ ID NO:70 -- Oligonucleotide primer (forward) used for producing the hpEIN2[G:U] fragment, with every C replaced with T (EIN2gu-F) SEQ ID NO:71 - Oligonucleotide primer (reverse) used for producing the hpEIN2[G:U] fragment, with every C replaced with T (EIN2gu-R) SEQ ID NO:72 -. Oligonucleotide primer (forward) used for producing the hpCHS[G:U] fragment, with every C replaced with T (CHSgu-F) SEQ ID NO:73 — Oligonucleotide primer (reverse) used for producing the hpCHS[G:U] fragment, with every C replaced with T (CHSgu-R) SEQ ID NO:74 -. Oligonucleotide primer (forward) used for producing the hpEIN2[G:U / U:G] fragment, with every C replaced with T (asEIN2gu-F) SEQ ID NO:75 - Oligonucleotide primer (reverse) used for producing the hpEIN2[G:U / U:G] fragment with every C replaced with T (asEIN2gu-R) SEQ ID NO:76 -- Oligonucleotide primer (forward) used for producing the hpCHS[G:U / U:G] fragment, with every C replaced with T (asCHSgu-F) SEQ ID NO:77 - Oligonucleotide primer (reverse) used for producing the hpCHS[G:U / U:G] fragment, with every C replaced with T (asCHSgu-R) SEQ ID NO:78 — Nucleotide sequence encoding forward primer (CHS-200-F2) SEQ ID NO:79 — Nucleotide sequence encoding reverse primer (CHS-200-R2) SEQ ID NO:80 — Nucleotide sequence encoding forward primer (Actin2-For) SEQ ID NO:81 — Nucleotide sequence encoding reverse primer (Actin2-Rev) SEQ ID NO:82 — Nucleotide sequence encoding forward primer (Top-35S-F2) SEQ ID NO:83 — Nucleotide sequence encoding reverse primer (Top-35S-R2) SEQ ID NO:84 — Nucleotide sequence encoding forward primer (Link-35S-F2) SEQ ID NO:85 — Nucleotide sequence encoding reverse primer (Link-EIN2-R2) SEQ ID NO:86 — Ribonucleotide sequence of sense si22 SEQ ID NO:87 — Ribonucleotide sequence of antisense si22 SEQ ID NO:88 — Ribonucleotide sequence of forward primer SEQ ID NO:89 — Ribonucleotide sequence of reverse primer SEQ ID NO:90 — Ribonucleotide sequence of forward primer SEQ ID NO:91 — Ribonucleotide sequence of reverse primer SEQ ID NO:92 — Possible modifications of dsRNA molecules SEQ ID NO:93 — Nucleotide sequence of a cDNA corresponding to the Brassica napus DDM] gene (Accession No. XR_001278527). SEQ ID NO:94 — Nucleotide sequence of a chimeric DNA encoding a hairpin RNAi (hpRNA) construct targeting a DDM1 gene of B. napus. SEQ ID NO:95 — Nucleotide sequence of a chimeric DNA encoding a hairpin RNAi (hpRNA) construct with G:U basepairs, targeting a DDMI gene of B. napus. SEQ ID NO:96 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct, targeting a DDM1 gene of B. napus. SEQ ID NO:97 — Nucleotide sequence of cDNA corresponding to A. thaliana FANCM gene (Accession No. NM_001333162). SEQ ID NO:98 — Nucleotide sequence of a chimeric DNA encoding a hairpin RNAi (hpRNA) construct targeting a FANCM gene of A. thaliana. SEQ ID NO:99 — Nucleotide sequence of a chimeric DNA encoding a hairpin RNAi (hpRNA) construct with G:U basepairs, targeting a FANCM gene of A. thaliana. SEQ ID NO:100 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct, targeting a FANCM gene of A. thaliana. SEQ ID NO:101 - Nucleotide sequence of cDNA corresponding to B. napus FANCM gene (Accession No. XM_022719486.1). SEQ ID NO:102 — Nucleotide sequence of a chimeric DNA encoding a hairpin RNAi (hpRNA) construct targeting a FANCM gene of B. napus. SEQ ID NO:103 — Nucleotide sequence of a chimeric DNA encoding a hairpin RNAi (hpRNA) construct with G:U basepairs, targeting a FANCM gene of B. napus. SEQ ID NO:104 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct, targeting a FANCM gene of B. napus. SEQ ID NO:105 — Nucleotide sequence of the protein coding region of the cDNA corresponding to the Nicotiana benthamiana TOR gene. SEQ ID NO:106 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a TOR gene of N. benthamiana. SEQ ID NO:107 — Nucleotide sequence of the protein coding region of the cDNA corresponding to the acetolactate synthase (ALS) gene of barley, Hordeum vulgare (Accession No. LT601589). SEQ ID NO:108 — Nucleotide sequence of a chimeric DNA encoding a ledRNA targeting the ALS gene of barley (H. vulgare). SEQ ID NO:109 - Nucleotide sequence of the protein coding region of the cDNA corresponding to the HVYNCEDI gene of barley Hordeum vulgare (Accession No. AK361999). SEQ ID NO:110 — Nucleotide sequence the protein coding region of the cDNA corresponding to the HVYNCED2 gene of barley Hordeum vulgare (Accession No. DQ145931). SEQ ID NO:111 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting the NCEDI genes of barley Hordeum vulgare and wheat Triticum aestivum. SEQ ID NO:112 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting the NCED2 genes of barley Hordeum vulgare and wheat Triticum aestivum. SEQ ID NO:113 — Nucleotide sequence of the protein coding region of a cDNA corresponding to the barley gene encoding ABA-OH-2 (Accession No. DQ145933). SEQ ID NO:114 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting the ABA-OH-2 genes of barley Hordeum vulgare and wheat Triticum aestivum. SEQ ID NO:115 — Nucleotide sequence of the protein coding region of a cDNA corresponding to the A. thaliana gene encoding EIN2 (At5g03280). SEQ ID NO:116 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting the EIN2 gene of A. thaliana. SEQ ID NO:117 — Nucleotide sequence of the protein coding region of a cDNA corresponding to the A. thaliana gene encoding CHS (Accession No. NM_121396). SEQ ID NO:118 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting the CHS gene of A. thaliana. SEQ ID NO:119 — Nucleotide sequence of the protein coding region of a cDNA corresponding to the L. angustifolius N-like gene (Accession No. XM_019604347). SEQ ID NO:120 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting the L. angustifolius N-like gene. SEQ ID NO:121 — Nucleotide sequence of the protein coding region of a cDNA corresponding to a Vitis pseudoreticulata MLO gene (Accession No. KR362912). SEQ ID NO:122 — Nucleotide sequence of a chimeric DNA encoding a first ledRNA construct targeting a Vitis MLO gene. SEQ ID NO:123 — Nucleotide sequence of the protein coding region of the cDNA corresponding to the MpC002 gene of Myzus persicae. SEQ ID NO:124 — Nucleotide sequence of the protein coding region of the cDNA corresponding to the MpRack-1 gene of Myzus persicae. SEQ ID NO:125 — Nucleotide sequence of the chimeric construct encoding the ledRNA targeting M.persicae C002 gene. SEQ ID NO:126 — Nucleotide sequence of the chimeric construct encoding the ledRNA targeting M.persicae Rack-1 gene. SEQ ID NO:127 — Nucleotide sequence of the cDNA corresponding to the Helicoverpa armigera ABCwhite gene. SEQ ID NO:128 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a ABC transporter white gene of Helicoverpa armigera. SEQ ID NO:129 — Nucleotide sequence of the cDNA corresponding to the Linepithema humile PBAN-type neuropeptides-like (XM_012368710). SEQ ID NO:130 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a PBAN gene in Argentine ants (Accession No. XM_012368710). SEQ ID NO:131 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a gene encoding V-type proton ATPase catalytic subunit A (Accession No. XM_023443547) of L. cuprina. SEQ ID NO:132 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a gene encoding RNAse 1 / 2 of L. cuprina. SEQ ID NO:133 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a gene encoding chitin synthase of L. cuprina. SEQ ID NO:134 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a gene encoding ecdysone receptor (EcR) of L. cuprina. SEQ ID NO:135 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a gene encoding gamma-tubulin 1 / 1-like of L. cuprina. SEQ ID NO:136 — TaMlo target gene (AF384144). SEQ ID NO:137 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a gene encoding TaMlo. SEQ ID NO:138 — Nucleotide sequence of the protein coding region of a cDNA corresponding to a Vitis pseudoreticulata MLO gene (Accession No. KR362912). SEQ ID NO:139 — Nucleotide sequence of a chimeric DNA encoding a first ledRNA construct targeting a Vitis MLO gene. SEQ ID NO:140 - Cyp51 homolog (Accession No. KK764651.1, locus RSAGS_00934). SEQ ID NO:141 — Cyp51 homolog 2 (Accession No. KK764892.1, locus number RSAGS_12664). SEQ ID NO:142 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a gene encoding Cyp31. SEQ ID NO:143 — CesA3 target gene (Accession No. IN561774.1). SEQ ID NO:144 — Nucleotide sequence of a chimeric DNA encoding a ledRNA construct targeting a gene encoding CesA3. SEQ ID NO:145 — VRN2B gene sequence (Triticum monococcum). SEQ ID NO:146 — LED- VRN 2 construct. SEQ ID NO:147 — VRN2 stem sequence. SEQ ID NO:148 - LED- VRN 2 construct Loop sequence 1. SEQ ID NO:149 - LED- VRN 2 construct Loop sequence 2. SEQ ID NO:150 - Sequence encoding the LedVRN2 molecule. SEQ ID NO:151 - Nucleotide sequence of the cDNA for Triticum aestivum cultivar Chinese Spring VRN-A1 cDNA protein coding sequence (TaVRN1-Al, Accession No. KR422423.1). SEQ ID NO:152 - Nucleotide sequence of the cDNA for Triticum aestivum flowering locus T cDNA sequence (TaFT, Accession No. AY705794.1). The protein coding sequence is nucleotides 19-549. SEQ ID NO:153 - Nucleotide sequence of the cDNA sequence for Hordeum vulgare subsp. spontanewm MADS box transcription factor (HvVRNI, Accession No. AY896051) gene. The protein coding sequence is nucleotides 8-403. SEQ ID NO:154 - Nucleotide sequence of the cDNA for Hordeum vulgare cultivar Dairokkaku ZCCT-Hb (HvVRN2, Accession No. AY485978) gene, partial cDNA. SEQ ID NO:155 - Nucleotide sequence of the cDNA for Hordeum vulgare cultivar Stander FT protein (HvFT, Accession No. DQ898519) gene. SEQ ID NO:156 - Nucleotide sequence of the cDNA for Oryza sativa Japonica Group phytochrome B-like gene, transcript variant X1 (OsPhyB, LOC4332623, OSNPB_030309200). SEQ ID NO:157 - Nucleotide sequence of the cDNA for Oryza sativa Constans-like 4 gene, OsCol4 protein (Accession No. HC084637). SEQ ID NO:158 - Nucleotide sequence of the cDNA sequence of the Oryza sativa Japonica Group protein RFT1 homolog (OsRFT1, LOC4343254, OSNPB_070486100) gene. The protein coding sequence is nucleotides 167-1753. SEQ ID NO:159 - Nucleotide sequence of the cDNA sequence of the Oryza sativa AP2-like ethylene-responsive transcription factor TOE3 OsSNB (OSNPB_070235800). The protein coding sequence is nucleotides 213-1520. SEQ ID NO:160 - Nucleotide sequence of the cDNA sequence for Oryza sativa Japonica Group AP2-like ethylene-responsive transcription factor TOE3 gene, transcript variant X1, (OsIDS1, LOC4334582, Os03g0818800). The protein coding sequence is nucleotides 575-1876. SEQ ID NO:161 - Nucleotide sequence of the cDNA sequence for Oryza sativa Japonica Group GIGANTEA-like gene, transcript variant X1, (OsGI, LOC4325329, OSNPB_010182600). The protein coding sequence is nucleotides 440-3919. SEQ ID NO:162 - Nucleotide sequence of the cDNA sequence for Oryza sativa OsMADSS0 (homolog of AtSOC1) (HC084627). The protein coding sequence is nucleotides 23-712. SEQ ID NO:163 - Nucleotide sequence of the cDNA sequence for Oryza sativa Japonica Group OsMADSS55 (homolog of AtSOC1) (Accession No. AY345223). SEQ ID NO:164 - Nucleotide sequence of the cDNA sequence for Oryza sativa Japonica Group transcription factor FL (OsLFY, LOC4336857, Os04g0598300). The protein coding sequence is nucleotides 233-1399. SEQ ID NO:165 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays cultivar Assiniboine ZmMADS1 / ZmM5 (LOC542042, Accession No. HM993639), partial sequence. SEQ ID NO:166 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays cultivar B73 phytochrome Al apoprotein PHYA (Accession No. AY234826). Protein coding region is nucleotides 118-3510. SEQ ID NO:167 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays phytochrome A2 apoprotein PHYA2 (LOC115101004, Accession No. AY260865). Protein coding region is nucleotides 141-3533. SEQ ID NO:168 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays phytochrome B1 apoprotein PHYBI (LOC100383702, Accession No. AY234827). Protein coding region is nucleotides 1-3483. SEQ ID NO:169 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays phytochrome B2 apoprotein PHYB2 (Accession No. AY234828). Protein coding region is nucleotides 1-3498. SEQ ID NO:170 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays phytochrome C1 apoprotein PHYC1 (Accession No. AY234829). Protein coding region is nucleotides 48-3455. SEQ ID NO:171 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays phytochrome C2 apoprotein PHYC2 (Accession No. AY234830). Protein coding region is nucleotides 141-3533. SEQ ID NO:172 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays flowering-time protein isoforms alpha and beta (ZmLD), alternatively spliced products (Accession No. AF166527). Protein coding region is nucleotides 122-3669. SEQ ID NO:173 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays cultivar A632 floricaula / leafy-like 1 (ZmFL1) (Accession No. AY179882). Protein coding region is nucleotides 27-1199. SEQ ID NO:174 - Nucleotide sequence of the cDNA of gene encoding Zea mays cultivar A632 floricaula / leafy-like 2 (ZmFL2) (Accession No. AY789023). SEQ ID NO:175 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays cultivar A554 DWARFS gene (Accession No. AF413203), partial cDNA. SEQ ID NO:176 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays kaurene synthase A (ZmANI protein, Accession No. L37750). Protein coding region is nucleotides 105-2573. SEQ ID NO:177 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays zinc finger protein ID1 (ZmID1 protein, Accession No. AF058757). Protein coding region is nucleotides 112-1419. SEQ ID NO:178 - Nucleotide sequence of the cDNA sequence of gene encoding Zea mays ZCN8 (ZmCNS8 protein, LOC100127519). Protein coding region is nucleotides 60-672. SEQ ID NO:179 - Nucleotide sequence of the cDNA for Brassica napus MADS-box (FLC1) protein gene (BnFLC1-A10, Accession No. AY036888, BnaA10g22080D). The protein coding sequence is nucleotides 68-658. SEQ ID NO:180 - Nucleotide sequence of the cDNA for Brassica napus MADS-box protein (FLC2) gene (BnFLC2, Accession No. AY036889). The protein coding sequence is nucleotides 34-621. SEQ ID NO:181 - Nucleotide sequence of the cDNA for Brassica napus MADS-box protein (FLC3) (BnFLC3, Accession No. AY036890). The protein coding sequence is nucleotides 46-636. SEQ ID NO:182 - Nucleotide sequence of the cDNA for Brassica napus MADS-box protein (FLC4) (BnFLC4, Accession No. AY036891). The protein coding sequence is nucleotides 147-734. SEQ ID NO:183 - Nucleotide sequence of the cDNA for Brassica napus MADS-box protein (FLCS) (BnFLCS5, Accession No. AY036892). The protein coding sequence is nucleotides 63-736. SEQ ID NO:184 - Nucleotide sequence of the cDNA for Brassica napus Frigida gene (BnFRI, BnaAQ3g13320D). SEQ ID NO:185 - Nucleotide sequence of the cDNA for Brassica napus linkage group A2 flowering locus T (FT) gene (BnFT, BnaA02g12130D). SEQ ID NO:186 - Nucleotide sequence of the cDNA sequence for Medicago truncatula cultivar Jester FTal protein (MtFTal, Accession No. HQ721813) gene. The protein coding sequence is nucleotides 233-1399. SEQ ID NO:187 - Nucleotide sequence of the ¢cDNA sequence for Medicago truncatula cultivar Jester FTb1 protein (MtFTb1, Accession No. HQ721815) gene. The protein coding sequence is nucleotides 233-1399. SEQ ID NO:188 - Nucleotide sequence of the cDNA sequence for Medicago sativa Frigida-like protein mRNA, (MsFRI-L, Accession No. JX173068, Chao et al., 2013). The protein coding sequence is nucleotides 7-1563. SEQ ID NO:189 - Nucleotide sequence of the cDNA sequence for Medicago sativa subsp. caerulea shatterproof mRNA, (MsSOCla / McaeSHP; Accession No. JX297565). The protein coding sequence is from nucleotide 31. SEQ ID NO:190 - Nucleotide sequence of the cDNA sequence for Medicago sativa FT (FT) gene, (MsFT, Accession No. JF681135). SEQ ID NO:191 - Nucleotide sequence of the cDNA sequence for Glycine max MADS-box protein FLOWERING LOCUS C (GmFLC) encoded by the gene GLYMA_05G148700 (Accession No. XM_014775674, LOC100804540), transcript variant X1, mRNA. The protein coding sequence is nucleotides 90-686. SEQ ID NO:192 - Nucleotide sequence of the cDNA sequence for Glycine max MADS-box protein FLOWERING LOCUS C encoded by the gene GLYMA_05G148700 (Accession No. XM_003524857.4), transcript variant X2. The protein coding sequence is nucleotides 72-665. SEQ ID NO:193 - Nucleotide sequence of the cDNA sequence for Glycine max MADS-box protein FLOWERING LOCUS C encoded by the gene GLYMA_05G148700 (Accession No. XR_001388453), transcript variant X3. The protein coding sequence is nucleotides 90-653. SEQ ID NO:194 - Nucleotide sequence of the cDNA sequence for Glycine max MADS-box protein FLOWERING LOCUS C encoded by the gene GLYMA_05G148700 (Accession No. XM_006580064), transcript variant X4. The protein coding sequence is nucleotides 90-641. SEQ ID NO:195 - Nucleotide sequence of the cDNA sequence for Glycine max MADS-box protein FLOWERING LOCUS C encoded by the gene GLYMA_05G148700 (Accession No. XM_006580065), transcript variant X5. The protein coding sequence is nucleotides 90-605. SEQ ID NO:196 - Nucleotide sequence of the cDNA sequence for Glycine max MADS-box protein FLOWERING LOCUS C encoded by the gene GLYMA_05G148700 (Accession No. XR_414429.3), transcript variant X6. The protein coding sequence is nucleotides 90-587. SEQ ID NO:197 - Nucleotide sequence of the cDNA sequence for Glycine max MADS-box protein FLOWERING LOCUS C encoded by the gene GLYMA_05G148700 (Accession No. XM_014775675), transcript variant X7. The protein coding sequence is nucleotides 90-587. SEQ ID NO:198 - Nucleotide sequence of the cDNA sequence for Glycine max MADS-box protein FLOWERING LOCUS C encoded by the gene GLYMA_05G148700 (Accession No. XM_014775676), transcript variant X8. The protein coding sequence is nucleotides 90-587. SEQ ID NO:199 - Nucleotide sequence of the cDNA sequence for Glycine max MADS-box protein FLOWERING LOCUS C encoded by the gene GLYMA_05G148700 (Accession No. XM_006580067), transcript variant X9. The protein coding sequence is nucleotides 90-575. SEQ ID NO:200 - Nucleotide sequence of the cDNA sequence of gene encoding Glycine max protein SUPPRESSOR OF FRI 4 (LOC100819009), transcript variant X3. (Accession No. XM_003530888). The protein coding sequence is nucleotides 145- 1257. SEQ ID NO:201 - Nucleotide sequence of the cDNA sequence of gene encoding Glycine max protein FRIGIDA-like protein 4a (GmFRI4a, LOC100805780, Accession No. NM_001360372). The protein coding sequence is nucleotides 77-1828. SEQ ID NO:202 - Nucleotide sequence of the cDNA sequence of gene encoding Glycine max protein protein FLOWERING LOCUS T (FT2A, GLYMA_16G150700, Accession No. NM_001253256). The protein coding sequence is nucleotides 78-605. SEQ ID NO:203 - Nucleotide sequence of the cDNA sequence of gene encoding Glycine max protein phytochrome A, transcript variant X3 (GmPhyA3, Accession No. XM_014771785.2). The protein coding sequence is nucleotides 615-3899. SEQ ID NO:204 - Nucleotide sequence of the cDNA sequence of gene encoding Glycine max protein protein GIGANTEA, transcript variant 1 (GmGIGANTEA Accession No. NM_001354790). The protein coding sequence is nucleotides 419-3946. SEQ ID NO:205 - Nucleotide sequence of the cDNA sequence of gene encoding Beta vulgaris subsp. vulgaris genotype KWS$2320 bolting time control 1 (BTC1, Accession No. HQ709091). Protein coding region is nucleotides 307-2670. SEQ ID NO:206 - Nucleotide sequence of the cDNA sequence of gene encoding Beta vulgaris flowering locus T-like protein (FT1) gene (BVFT1, Accession No. HM448909). SEQ ID NO:207 - Nucleotide sequence of the cDNA sequence of gene encoding Beta vulgaris flowering locus T-like protein (FT2) gene (BVFT2, Accession No. HM448911). SEQ ID NO:208 - Nucleotide sequence of the cDNA sequence of gene encoding Brassica rapa cultivar IMB 218dh FLC2 (FLC2, Accession No. AH012704), partial sequence. SEQ ID NO:209 - Nucleotide sequence of the cDNA sequence of gene encoding Brassica rapa FRIGIDA (FRI, Accession No. HQ615935). SEQ ID NO:210 - Nucleotide sequence of the cDNA sequence of Medicago truncatula clone MTYFL_FM_FN_FO1G-C-11 (MtYFL, Accession No. BT053010). Protein coding region is nucleotides 78-1136. SEQ ID NO:211 - Nucleotide sequence of the cDNA sequence of Allium cepa GIGANTEA (Gla) (AcGla, Accession No. GQ232756). Protein coding region is nucleotides 27-3353. SEQ ID NO:212 - Nucleotide sequence of the cDNA sequence of Allium cepa FKF1 (FKF1, Accession No. GQ232754). Protein coding region is nucleotides 53-1905. SEQ ID NO:213 - Nucleotide sequence of the cDNA sequence of Allium cepa ZEITLUPE (AcZTL, Accession No. GQ232755). Protein coding region is nucleotides 128-1963. SEQ ID NO:214 - Nucleotide sequence of the cDNA sequence of Allium cepa ACABR20 CONSTANS-like protein (AcCOL, Accession No. GQ232751). Protein coding region is nucleotides 22-972. SEQ ID NO:215 - Nucleotide sequence of the cDNA sequence of Allium cepa ACAEE%6 protein (AcFTL, Accession No. CF438000). Protein coding region is nucleotides 396-818. SEQ ID NO:216 - Nucleotide sequence of the cDNA sequence of Allium cepa cultivar CUDH2150 FT1 (AcFT1, Accession No. KC485348). Protein coding region is nucleotides 1-534. SEQ ID NO:217 - Nucleotide sequence of the cDNA sequence of Allium cepa cultivar CUDH2150 FT2 (AcFT2, Accession No. KC485349). Protein coding region is nucleotides 42-566. SEQ ID NO:218 - Nucleotide sequence of the cDNA sequence of Allium cepa cultivar CUDH2150 FT6 (AcFT6, Accession No. KC485353). Protein coding region is nucleotides 6-560. SEQ ID NO:219 - Nucleotide sequence of the cDNA sequence of Allium cepa clone ACAGK28 phytochrome A (PHYA) (AcPHYA, Accession No. GQ232753), partial sequence. Protein coding region is nucleotides 1-1119. SEQ ID NO:220 - Nucleotide sequence of the cDNA sequence of Allium cepa clone ACADQ29 COP1 (AcCOPI, Accession No. CF451443). Protein coding region is nucleotides 249-647. SEQ ID NO:221 - Nucleotide sequence of the cDNA sequence of Lactuca sativa protein HEADING DATE 3A-like protein (LsFT, LOC111907824). Protein coding region is nucleotides 71-595. SEQ ID NO:222 - Nucleotide sequence of the cDNA sequence of Lactuca sativa protein MOTHER of FT and TFL1-like (LsFL1-like, LOC111903066, Accession No. XM_023898861). SEQ ID NO:223 - Nucleotide sequence of the cDNA sequence of Lactuca sativa protein MOTHER of FT and TFL1 homolog 1-like (LsTFL1, LOC111903054, Accession No. XM_023898849). SEQ ID NO:224 - Nucleotide sequence of the cDNA sequence of Lactuca sativa FLC (LsFLC, LOC111876490, Accession No. JI588382). SEQ ID NO:225 - Nucleotide sequence of the cDNA sequence of Lactuca sativa MADS-box protein SOCI-like (LsSOC1, LOC111912847, Accession No. XM_023908569). Protein coding region is nucleotides 159-809. SEQ ID NO:226 - Nucleotide sequence of the cDNA sequence of Lactuca sativa MADS-box protein SOCl-like (LsSOC1-like, LOC111880753, Accession No. XM_023877169), transcript variant X1. Protein coding region is nucleotides 129-782. SEQ ID NO:227 - Nucleotide sequence of the cDNA sequence of Lactuca sativa MADS-box protein SOC1-like (LsSOCI-like, LOC111878575). Protein coding region is nucleotides 166-819. SEQ ID NO:228 - Nucleotide sequence of the cDNA sequence of Lactuca sativa floricaula / leafy homolog (LsLFY, LOC111892192, Accession No. XM_023888266). Protein coding region is nucleotides 1-1278. SEQ ID NO:229 and SEQ ID NO:230 — Oligonucleotide primers. DETAILED DESCRIPTION OF THE INVENTION General Techniques and Definitions Unless specifically defined otherwise, all technical and scientific terms used herein shall be taken to have the same meaning as commonly understood by one of ordinary skill in the art (e.g., in cell culture, molecular genetics, gene silencing, protein chemistry, and biochemistry). Unless otherwise indicated, the recombinant protein, cell culture, and immunological techniques utilized in the present invention are standard procedures, well known to those skilled in the art. Such techniques are described and explained throughout the literature in sources such as, J. Perbal, A Practical Guide to Molecular Cloning, John Wiley and Sons (1984), J. Sambrook et al., Molecular Cloning: A Laboratory Manual, Cold Spring Harbour Laboratory Press (1989), T.A. Brown (editor), Essential Molecular Biology: A Practical Approach, Volumes 1 and 2, IRL Press (1991), D.M. Glover and B.D. Hames (editors), DNA Cloning: A Practical Approach, Volumes 1-4, IRL Press (1995 and 1996), and F.M. Ausubel et al. (editors), Current Protocols in Molecular Biology, Greene Pub. Associates and Wiley- Interscience (1988, including all updates until present), Ed Harlow and David Lane (editors) Antibodies: A Laboratory Manual, Cold Spring Harbour Laboratory, (1988), and J.E. Coligan et al. (editors) Current Protocols in Immunology, John Wiley & Sons (including all updates until present). The term “antisense regulatory element” or “antisense ribonucleic acid sequence” or “antisense RNA sequence” as used herein means an RNA sequence that is at least partially complementary to at least a part of a target RNA molecule to which it hybridizes. In certain embodiments, an antisense RNA sequence modulates (increases or decreases) the expression or amount of a target RNA molecule or its activity, for example through reducing translation of the target RNA molecule. In certain embodiments, an antisense RNA sequence alters splicing of a target pre-mRNA resulting in a different splice variant. Exemplary components of antisense sequences include, but are not limited to, oligonucleotides, oligonucleosides, oligonucleotide analogues, oligonucleotide mimetics, and chimeric combinations of these. The term “antisense activity” is used in the context of the present disclosure to refer to any detectable and / or measurable activity attributable to the hybridization of an antisense RNA sequence to its target RNA molecule. Such detection and / or measuring may be direct or indirect. In an embodiment, antisense activity is assessed by detecting and or measuring the amount of target RNA molecule transcript. Antisense activity may also be detected as a change in a phenotype associated with the target RNA molecule. As used herein, the term “target RNA molecule” refers to a gene transcript that is modulated by an antisense RNA sequence according to the present disclosure. Accordingly, “target RNA molecule” can be any RNA molecule the expression or activity of which is capable of being modulated by an antisense RNA sequence. Exemplary target RNA molecules include, but are not limited to, RNA (including, but not limited to pre-mRNA and mRNA or portions thereof) transcribed from DNA encoding a target protein, rRNA, tRNA, small nuclear RNA, and miRNA, including their precursor forms. The target RNA may be the genomic RNA of a plant, or an RNA molecule derived therefrom. For example, the target RNA molecule can be an RNA from an endogenous gene (or mRNA transcribed from the gene) or a gene which is introduced or may be introduced into the plant cell whose expression is associated with a particular phenotype, trait, disorder or disease state, or a nucleic acid molecule from an infectious agent. In an embodiment, the target RNA molecule is in a plant cell. In another example, the target RNA molecule encodes a protein. In this context, antisense activity can be assessed by detecting and or measuring the amount of target protein, for example through its activity such as enzyme activity, or a function other than as an enzyme, or through a phenotype associated with its function. As used herein, the term “target protein” refers to a protein that is modulated by an antisense RNA sequence according to the present disclosure. In certain embodiments, antisense activity is assessed by detecting and / or measuring the amount of target RNA molecules and / or cleaved target RNA molecules and / or alternatively spliced target RNA molecules. Antisense activity can be detected or measured using various methods. For example, antisense activity can be detected or assessed by comparing activity in a particular sample and comparing the activity to that of a control sample. The term “targeting” is used in the context of the present disclosure to refer to the association of an antisense RNA sequence to a particular target RNA molecule or a particular region of nucleotides within a target RNA molecule. In an example, an antisense RNA sequence according to the present disclosure shares complementarity with at least a region of a target RNA molecule. In this context, the term “complementarity” refers to a sequence of ribonucleotides that is capable of base pairing with a sequence of ribonucleotides on a target RNA molecule, through hydrogen bonding between bases on the ribonucleotides. For example, in RNA, adenine (A) is complementary to uracil (U) and guanine (G) to cytosine (C). In certain embodiments, “complementary base” refers to a ribonucleotide of an antisense RNA sequence that is capable of base pairing with a ribonucleotide of a sense RNA sequence in an RNA molecule of the invention or of its target RNA molecule. For example, if a ribonucleotide at a certain position of an antisense RNA sequence is capable of hydrogen bonding with a ribonucleotide at a certain position of a target RNA molecule, then the position of hydrogen bonding between the antisense RNA sequence and the target RNA molecule is considered to be complementary at that ribonucleotide. In contrast, the term “non-complementary” refers to a pair of ribonucleotides that do not form hydrogen bonds with one another or otherwise support hybridization. The term “complementary” can also be used to refer to the capacity of an antisense RNA sequence to hybridize to another nucleic acid through complementarity. In certain embodiments, an RNA sequence and its target are complementary to each other when a sufficient number of corresponding positions in each molecule are occupied by ribonucleotides that can bond with each other to allow stable association between the antisense RNA sequence and a sense RNA sequence in the RNA molecule of the invention and / or the target RNA molecule. One skilled in the art recognizes that the inclusion of mismatches is possible without eliminating the ability of the antisense RNA sequence and target to remain in association. Therefore, described herein are antisense RNA sequence that may comprise up to about 20% nucleotides that are mismatched (i.e., are not complementary to the corresponding nucleotides of the target). Preferably the antisense compounds contain no more than about 15%, more preferably not more than about 10%, most preferably not more than 5% or no mismatches. The remaining ribonucleotides are complementary or otherwise do not disrupt hybridization (e.g., G:U or A:G pairs) between the antisense RNA sequence and the sense RNA sequence or the target RNA molecule. One of ordinary skill in the art would recognise the antisense RNA sequence s described herein are at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% (fully) complementary to at least a region of a target RNA molecule. The term “RNA molecules of the invention” is used herein to refer to RNA molecules and chimeric RNA molecules. In addition, an RNA molecule of the invention can be a chimeric RNA molecule. As used herein, "chimeric RNA molecule" refers to any RNA molecule that is not naturally found in nature. In an example, chimeric RNA molecules disclosed herein have been modified to create mismatches in region(s) of dsRNA. For example, chimeric RNA molecules may be modified to convert cytosines to uracils. In an example, chimeric RNA molecules have been modified via treatment with bisulfite for a time and under conditions sufficient to convert non-methylated cytosines to uracils. One of skill in the art would appreciate that various ribonucleotide combinations can base pair. Both canonical and non-canonical base pairings are contemplated by the present disclosure. In an example, a base pairing can comprise A:T or G:C in a DNA molecule or U:A or G:C in an RNA molecule. In another example, a base pairing may comprise A:G or G:T or U:G. The term “canonical base pairing” as used in the present disclosure means base pairing between two nucleotides which are A:T or G:C for deoxyribonucleotides or A:U or G:C for ribonucleotides. The term “non-canonical base pairing” as used in the present disclosure means an interaction between the bases of two nucleotides other than canonical base pairings, in the context of two DNA or two RNA sequences. For example, non-canonical base pairing includes pairing between G and U (G:U) or between A and G (A:G). Examples of non-canonical base pairing include purine — purine or pyrimidine — pyrimidine. Most commonly in the context of this disclosure, the non-canonical base pairing is G:U. Other examples of non-canonical base pairs, less preferred, are A:C, GT, G:G and AA. The present disclosure refers to RNA components that “hybridize” across a series of ribonucleotides. Those of skill in the art will appreciate that terms such as “hybridize” and “hybridizing” are used to describe molecules that anneal based on complementary nucleic acid sequences. Such molecules need not be 100% complementary in order to hybridize (i.e. they need not “fully base pair”). For example, there may be one or more mismatches in sequence complementarity. In an example, RNA components defined herein hybridise under stringent hybridization conditions. The term “stringent hybridization conditions” refers to parameters with which the art is familiar, including the variation of the hybridization temperature with length of an RNA molecule. Ribonucleotide hybridization parameters may be found in references which compile such methods, Sambrook, et al. (supra), and Ausubel, et al. (supra). For example, stringent hybridization conditions, as used herein, can refer to hybridization at 65°C in hybridization buffer (3.5xSSC, 0.02% Ficoll, 0.02% polyvinyl pyrrolidone, 0.02% Bovine Serum Albumin (BSA), 2.5 mM NaH:PO: (pH7), 0.5% SDS, 2 mM EDTA), followed by one or more washes in 0.2.xSSC, 0.01% BSA at 50°C. Shorter RNA components such as RNA sequences of 20-24 nucleotides in length hybridise under lower stringency conditions. The term "low stringency hybridization conditions" refers to parameters with which the art is familiar, including the variation of the hybridization temperature with length of an RNA molecule. For example, low stringency hybridization conditions, as used herein, can refer to hybridization at 42°C in hybridization buffer (3.5xSSC, 0.02% Ficoll, 0.02% polyvinyl pyrrolidone, 0.02% Bovine Serum Albumin (BSA), 2.5 mM NaH>PO4 (pH7), 0.5% SDS, 2 mM EDTA), followed by one or more washes in 0.2.xSSC, 0.01% BSA at 30°C. The present invention also encompasses RNA components that “fully base pair” across contiguous ribonucleotides. The term “fully base pair” is used in the context of the present disclosure to refer to a series of contiguous ribonucleotide base pairings. A fully base paired series of contiguous ribonucleotides does not comprise gaps or non- basepaired nucleotides within the series. The term “contiguous” is used to refer to a series of ribonucleotides. Ribonucleotides comprising a contiguous series will be joined by a continuous series of phosphodiester bonds, each ribonucleotide being directly bonded to the next. RNA molecules of the present invention comprise a sense sequence and a corresponding antisense sequence. The relationship between these sequences is defined herein. The sequence relationship and activity of the antisense sequence in relation to a target RNA molecule is also defined herein. The term “covalently linked” is used in the context of the present disclosure to refer to the link between the first and second RNA components or any RNA sequences or ribonucleotides. As one of skill in the art would appreciate, a covalent link or bond is a chemical bond that involves the sharing of electron pairs between atoms. In an example, the first and second RNA components or the sense RNA sequence and the antisense RNA sequence are covalently linked as part of a single RNA strand which may fold back on itself through self-complementarity. In this example, the components are covalently linked across one or more ribonucleotides by phosphodiester bonds. In the context of the present disclosure, the term “hybridization” means the pairing of complementary polynucleotides through basepairing of complementary bases. While not limited to a particular mechanism, the most common mechanism of pairing involves hydrogen bonding, which may be Watson-Crick hydrogen bonding, between complementary ribonucleotides. As used herein, the phrase “the RNA molecule reduces the target gene activity in the plant cell” or similar phrases means that the target gene transcript is present in the plant cell and exposure or contact of the cell expressing the target gene transcript to the target RNA molecule results in reduced levels and / or activity of the target gene transcript when compared to the same cell lacking the RNA molecule. In an embodiment, the target RNA molecule encodes a protein important for flowering. As an example, the RNA molecule can have a modulating effect on flowering by the plant. For example, the modulating effect can be early flowering. In another example, the modulating effect can be late flowering. In an example, RNA molecules according to the present disclosure and compositions comprising the same can be administered to a plant. As used herein, the term “unrelated in sequence to a target” refers to molecules having less than 50% identity along the full-length of the intervening RNA sequence. On the other hand, the term “related in sequence to a target” refers to molecules having 50% or more identity along the full-length of the intervening RNA sequence. As used herein, the term "genetically unmodified” or “non-transgenic” refers to plants that have not been modified by genetic engineering methods. As used herein, a "control" or "control plant” or "control plant cell" provides a reference point for measuring changes in phenotype of a subject plant or plant cell to which a RNA molecule disclosed herein has been delivered. In an example, the control plant or plant cell is a genetically similar plant or plant cell lacking an RNA molecule disclosed herein, preferably an isogenic plant or plant cell. For the avoidance of doubt, a control may be a single plant or a group of plants or a crop. Identification of a suitable control to provide a reference point for measuring changes in phenotype is considered well within the purview of those of skill in the art. RNA molecules herein that “modulate the timing of plant flowering” are RNA molecules that are able to increase or decrease the time to flowering of a plant. In an example, RNA molecules disclosed herein direct early flowering in plants compared to a control(s). In another example, RNA molecules disclosed herein direct late flowering in plants compared to a control(s). Flowering time of plants can be assessed by counting the number of days ("time to flower") between sowing or transplanting and the emergence of a first inflorescence. For example, the "flowering time" of a plant can be determined using the method as described in WO 2007 / 093444. In another example, flowering time can be measured indirectly based on the number of rosette leaves before bolting. The term “time of flower” and related terms has the common meaning in the art for each plant type being considered and is typically determined by visual inspection of the plant. The particular feature that indicates the onset of flowering may be different for different plant species. It generally means that the first flower of the plant opens or is fertilisable if the flower does not open. For grasses such as wheat, barley and rice, for example, the term "flowering" means that heads or (panicles) emerge. Terms such as "early flowering” or “early flowering time” are used herein to refer to plants which start to flower earlier than control plants. Hence these terms refer to plants that show an earlier start of flowering. In contrast, terms such as "late flowering” or “late flowering time" are used herein to refer to plants which start to flower later than control plants. Hence these terms refer to plants that show a later start to flowering. In an example, “early flowering” and “late flowering” can be determined by at least a statistically significantly change (decrease or increase) in flowering time compared to a control plant(s) as determined by a two-tailed Student's t-test or other appropriate statistical analysis, P-value < 0.05. As would be understood by those of skill in the art, the time to flower varies between plant species and between different plants lines or varieties within a species. Accordingly, in an example and depending on species, "early flowering" can refer to a reduction in time to flower by at least about 2 days, 3 days, 5 days, 10 days, 15 days, 20 days, 30 days, 40 days or more. In an example, early flowering refers to a reduction in time to flower by at least 5 to 40 days. In another example, early flowering refers to a reduction in time to flower by at least 5 to 40 days. In another example, early flowering refers to a reduction in time to flower by at least 10 to 30 days. For example, a reduction in time to flower of at least about 2 days, 3 days, 5 days, 10 days, 15 days, 20 days, 30 days or more can indicate early flowering in wheat. In an example, a reduction in time to flower of between 5 and 40 days indicates early flowering in wheat. In another example, a reduction in time to flower of between 10 and 30 days indicates early flowering in wheat. In another example, an early flowering plant has fewer rosette leaves before bolting than control plants. In contrast, in an example and depending on species, "late flowering" can refer to an increase in time to flower by at least about 2 days, 3 days, 5 days, 10 days, 15 days, 20 days, 30 days, 40 days or more. For example, an increase in time to flower of at least about 2 days, 3 days, 5 days, 10 days, 15 days, 20 days, 30 days, 40 days or more can indicate late flowering in wheat. In another example, a late flowering plant has fewer rosette leaves before bolting than control plants. As used herein, "vernalization” refers to a process by which flowering is accelerated in plants via exposure of the plant or seed from which the plant is grown to a temperature stimulus or an artificial equivalent. In one example, the artificial equivalent is delivering RNA molecule(s) described herein to a plant or a plant part, for example to seed. As used herein, a “target RNA or gene that modulates the timing of plant flowering” or an “RNA molecule that modulates the timing of plant flowering” is a target RNA, gene or RNA molecule which is involved in the genetic control of flowering in a plant and / or which influences, regulates or modulates the timing of flowering, including affecting the age or developmental stage of a plant at which it flowers and including genes which are involved in sensing environmental cues that lead to promotion or suppression of flowering. As used herein, the phrase "long-day conditions" refers to photoperiodic conditions where a dark period in a day is shorter than a threshold dark period required for photoperiodic responses (critical dark period). A 14-hour light / 10-hour dark photoperiod is typically used as a long-day condition. “Plants” included in the invention are any flowering plants, including both monocotyledonous and dicotyledonous plants. Examples of monocotyledonous plants include, but are not limited to, cereals such as wheat, barley, maize, rice, sorghum, pearl millet, rye and oats, grasses such as forage grasses and turfgrasses, vegetables such as asparagus, onions and garlic. Examples of dicotyledonous plants include, but are not limited to, vegetables such as such as tomato, legumes such as alfalfa, beans, peas, chickpeas, lupins and soybeans, peppers, lettuce, forage or feed plants such as alfalfa, clover, Brassica species e.g. cabbage, broccoli, cauliflower, brussel sprouts, rapeseed, mustard and radish, carrot, beets, eggplant, spinach, cucumber, squash, melons, cantaloupe, sunflowers, fiber crops such as cotton, ornamentals such as flowers and shrubs, and trees used in forestry such as poplar, eucalyptus and pine. Various other examples or plants and crops are discussed further below. The term “and / or”, e.g., “X and / or Y” shall be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning. As used herein, the term about, unless stated to the contrary, refers to + / - 20%, more preferably + / - 10%, of the designated value. Throughout this specification the word “comprise”, or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps. ledRN A Molecule In certain embodiments, RNA molecules of the present invention comprise a first RNA component which is covalently linked to a second RNA component. In preferred embodiments, the RNA molecule self-hybridizes or folds to form a “dumbbell” or ledRNA structure, for example see Figure 1. In an embodiment, the molecule further comprises one or more of the following: a linking ribonucleotide sequence which covalently links the first and second RNA components; a 5’ leader sequence; and, a 3’ trailer sequence. In an embodiment, the first RNA component consists of, in 5’ to 3’ order, a first 5’ ribonucleotide, a first RNA sequence and a first 3’ ribonucleotide, wherein the first 5’ and 3’ ribonucleotides basepair to each other in the RNA molecule, wherein the first RNA sequence comprises a first sense ribonucleotide sequence of at least 20 contiguous ribonucleotides, a first loop sequence of at least 4 ribonucleotides and a first antisense ribonucleotide sequence of at least 20 contiguous ribonucleotides, wherein the first antisense ribonucleotide sequence hybridises with the first sense ribonucleotide sequence in the RNA molecule, wherein the first antisense ribonucleotide sequence is capable of hybridising to a first region of a target RNA molecule which modulates the timing of plant flowering. In another embodiment, the first RNA component consists of, in 5° to 3’ order, a first 5° ribonucleotide, a first RNA sequence and a first 3° ribonucleotide, wherein the first 5° and 3’ ribonucleotides basepair to each other in the RNA molecule, wherein the first RNA sequence comprises a first sense ribonucleotide sequence of at least 20 contiguous ribonucleotides, a first loop sequence of at least 4 ribonucleotides and a first antisense ribonucleotide sequence of at least 20 contiguous ribonucleotides, wherein the first antisense ribonucleotide sequence fully basepairs with the first sense ribonucleotide sequence in the RNA molecule, wherein the first antisense ribonucleotide sequence is identical in sequence to the complement of a first region of a target RNA molecule. An example of this first RNA component of these two embodiments is shown schematically in the left-hand half of Figure 1A or the right- hand half of Figure 1B. In another embodiment, the first RNA component consists of a first 5’ ribonucleotide, a first RNA sequence and a first 3’ ribonucleotide, wherein the first 5° and 3’ ribonucleotides basepair with each other in the first RNA component, wherein the first RNA sequence comprises a first sense ribonucleotide sequence, a first loop sequence of at least 4 ribonucleotides and a first antisense ribonucleotide sequence, wherein the first sense ribonucleotide sequence and first antisense ribonucleotide sequence each of at least 20 contiguous ribonucleotides whereby the at least 20 contiguous ribonucleotides of the first sense ribonucleotide sequence fully basepair with the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence, wherein the at least 20 contiguous ribonucleotides of the first sense ribonucleotide sequence are substantially identical in sequence to a first region of a target RNA molecule. In these embodiments, the basepair formed between the first 5° ribonucleotide and the first 3” ribonucleotide is considered to be the terminal basepair of the dsRNA region formed by self-hybridization of the first RNA component, i.e it defines the end of the dsRNA region. In an embodiment, the first sense sequence has substantial sequence identity to a region of the target RNA, which identity may be to a sequence of less than 20 nucleotides in length. In an embodiment at least 15, at least 16, at least 17, at least 18, or at least 19 contiguous ribonucleotides, preferably at least 20 contiguous ribonucleotides, of the first sense ribonucleotide sequence and a first region of a target RNA molecule are at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or 99% identical in sequence. In another embodiment, the at least 15, at least 16, at least 17, at least 18, at least 19 contiguous ribonucleotides of the first sense ribonucleotide sequence and a first region of a target RNA molecule are 100% identical. In an embodiment, the first 3, first 4, first 5, first 6, or first 7 ribonucleotides from the 5° end of the first sense ribonucleotide sequence are 100% identical to the region of the target RNA molecule, with the remaining ribonucleotides being at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% identical to the target RNA molecule. In an embodiment the at least 20 contiguous ribonucleotides of the first sense ribonucleotide sequence and a first region of a target RNA molecule are at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical. Again, in this embodiment, the first 3, first 4, first 5, first 6, or first 7 ribonucleotides can be 100% identical to the region of the target RNA molecule, with the remaining ribonucleotides being at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to target RNA molecule. In another embodiment, the at least 20 contiguous ribonucleotides of the first sense ribonucleotide sequence and a first region of a target RNA molecule are 100% identical. In an embodiment, the first antisense sequence has substantial sequence identity to the complement of a region of the target RNA, which identity may be to a sequence of less than 20 nucleotides in length of the complement. In an embodiment at least 15, at least 16, at least 17, at least 18, or at least 19 contiguous ribonucleotides, preferably at least 20 contiguous ribonucleotides, of the first antisense ribonucleotide sequence and the complement of a first region of a target RNA molecule are at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or 99% identical in sequence. In another embodiment, the at least 15, at least 16, at least 17, at least 18, at least 19 contiguous ribonucleotides of the first antisense ribonucleotide sequence and the complement of the first region of the target RNA molecule are 100% identical. In an embodiment, the first 3, first 4, first 5, first 6, or first 7 ribonucleotides from the 5’ end of the first antisense ribonucleotide sequence are 100% identical to the complement of the region of the target RNA molecule, with the remaining ribonucleotides being at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% identical to the complement of the target RNA molecule. In an embodiment the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence and the complement of a first region of the target RNA molecule are at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical. Again, in this embodiment, the first 3, first 4, first 5, first 6, or first 7 ribonucleotides are 100% identical to the complement of the region of the target RNA molecule, with the remaining ribonucleotides being at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% identical to the complement of the target RNA molecule. In another embodiment, the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence and a first region of a target RNA molecule are 100% identical. In another embodiment, the second RNA component consists of, in 5’ to 3’ order, a second 5° ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, wherein the second 5° and 3’ ribonucleotides basepair, wherein the second RNA sequence comprises a second sense ribonucleotide sequence, a second loop sequence of at least 4 ribonucleotides and a second antisense ribonucleotide sequence, wherein the second sense ribonucleotide sequence basepairs with the second antisense ribonucleotide sequence. In this embodiment, the basepair formed between the second 5’ ribonucleotide and the second 3” ribonucleotide is considered to be the terminal basepair of the dsRNA region formed by self-hybridization of the second RNA component. In an embodiment, the RNA molecule comprises a 5’ leader sequence, or 5’ extension sequence, which may arise as a result of transcription from a promoter in the genetic construct, from the start site of transcription to the beginning of the polynucleotide encoding the remainder of the RNA molecule. It is preferred that this 5” leader sequence or 5° extension sequence is relatively short compared to the remainder of the molecule, and it may be removed from the RNA molecule post-transcriptionally, for embodiment by RNAse treatment. The 5’ leader sequence or 5° extension sequence may be mostly non-basepaired, or it may contain one or more stem-loop structures. In this embodiment, the 5° leader sequence can consist of a sequence of ribonucleotides which is covalently linked to the first 5’ ribonucleotide if the second RNA component is linked to the first 3’ ribonucleotide or to the second 5° ribonucleotide if the second RNA component is linked to the first 5’ ribonucleotide. In an embodiment, the 5 leader sequence is at least 10, at least 20, at least 30, at least 100, at least 200 ribonucleotides long, preferably to a maximum length of 250 ribonucleotides. In another embodiment, the 5° leader sequence is at least 50 ribonucleotides long. In an embodiment, the 5° leader sequence can act as an extension sequence for amplification of the RNA molecule via a suitable amplification reaction. For embodiment, the extension sequence may facilitate amplification via polymerase. In another embodiment, the RNA molecule comprises a 3’ trailer sequence or 3’ extension sequence which may arise as a result of transcription continuing until a transcription termination or polyadenylation signal in the construct encoding the RNA molecule. The 3’ trailer sequence or 3’ extension sequence may comprise a polyA tail. It is preferred that this 3 trailer sequence or 3’ extension sequence is relatively short compared to the remainder of the molecule, and it may be removed from the RNA molecule post-transcriptionally, for embodiment by RNAse treatment. The 3’ trailer sequence or 3’ extension sequence may be mostly non-basepaired, or it may contain one or more stem-loop structures. In this embodiment, the 3’ trailer sequence can consist of a sequence of ribonucleotides which is covalently linked to the second 3’ ribonucleotide if the second RNA component is linked to the first 3° ribonucleotide or to the first 3’ ribonucleotide if the second RNA component is linked to the first 5’ ribonucleotide. In an embodiment, the 3’ leader sequence is at least 10, at least 20, at least 30, at least 100, at least 200 ribonucleotides long, preferably to a maximum length of 250 ribonucleotides. In another embodiment, the 3’ leader sequence is at least 50 ribonucleotides long. In an embodiment, the 3” trailer sequence can act as an extension sequence for amplification of the RNA molecule via a suitable amplification reaction. For embodiment, the extension sequence may facilitate amplification via polymerase. In an embodiment, all except for two of the ribonucleotides are covalently linked to two other nucleotides i.e. the RNA molecule consists of only one RNA strand which has self-complementary regions, and so has only one 5’ terminal nucleotide and one 3’ terminal nucleotide. In another embodiment, all except for four of the ribonucleotides are covalently linked to two other nucleotides i.e. the RNA molecule consists of two RNA strands which have complementary regions which hybridise, and so has only two 5’ terminal nucleotides and two 3’ terminal nucleotides. In another embodiment, each ribonucleotide is covalently linked to two other nucleotides i.e the RNA molecule is circular as well as having self-complementary regions, and so has no 5’ terminal nucleotide and no 3’ terminal nucleotide. In an embodiment, the double-stranded region of the RNA molecule can comprise one or more bulges resulting from unpaired nucleotides in the sense RNA sequence or the antisense RNA sequence, or both. In an embodiment, the RNA molecule comprises a series of bulges. For embodiment, the double-stranded region of the RNA molecule may have 2, 3, 4, 5, 6, 7, 8, 9, 10 or more bulges. Each bulge may be, independently, one, two or more unpaired nucleotides, to as many as 10 nucleotides. Longer sequences may loop out of the sense or antisense sequences in the dsRNA region, which may basepair internally or remain unpaired. In another embodiment, the double-stranded region of the RNA molecule does not comprise a bulge i.e. is fully basepaired along the full length of the dsRNA region. In another embodiment, the first sense ribonucleotide sequence is covalently linked to the first 5° ribonucleotide without any intervening nucleotides, or the first antisense ribonucleotide sequence is covalently linked to the first 3’ ribonucleotide without any intervening nucleotides, or both. In another embodiment, there are at least one, at least two, at least three, at least four, at least five, at least six, at least seven, at least eight, at least nine, at least 10 intervening nucleotides. It is understood that such intervening nucleotides are unrelated in sequence to the target RNA molecule but may assist in stabilising the basepairing of adjacent sense and antisense sequences. In another embodiment, the 20 consecutive nucleotides of the first sense ribonucleotide sequence are covalently linked to the first 5’ ribonucleotide without any intervening nucleotides, and the 20 consecutive nucleotides of the first antisense ribonucleotide sequence are covalently linked to the first 3” ribonucleotide without any intervening nucleotides. In another embodiment, there are at least one, at least two, at least three, at least four, at least five, at least six, at least seven, at least eight, at least nine, at least 10 intervening nucleotides. The intervening nucleotides may be basepaired as part of the double-stranded region of the RNA molecule but are unrelated in sequence to the target RNA. They may assist in providing increased stability to the double-stranded region or to hold together two ends of the RNA molecule and not leave an unbasepaired 5’ or 3’ end, or both. In an embodiment, the above referenced first and second RNA components comprise a linking ribonucleotide sequence. In an embodiment, the linking ribonucleotide sequence acts as a spacer between the first sense ribonucleotide sequence that is substantially identical in sequence to a first region of a target RNA molecule and the other components of the molecule. For example, the linking ribonucleotide sequence may act as a spacer between this region and a loop. In another embodiment, the RNA molecule comprises multiple sense ribonucleotide sequences that are substantially identical in sequence to a first region of a target RNA molecule and a linking ribonucleotide sequence which acts as a spacer between these sequences. In an embodiment, at least two, at least three, at least four, at least five, at least six, at least seven, at least eight, at least nine, at least 10 ribonucleotide sequences that are substantially identical in sequence to a first region of a target RNA molecule are provided in the RNA molecule, each being separated from the other(s) by a linking ribonucleotide sequence. In an embodiment, the above referenced RNA molecules comprise a 5° leader sequence. In an embodiment, the 5’ leader sequence consists of a sequence of ribonucleotides which is covalently linked to the first 5° ribonucleotide if the second RNA component is linked to the first 3’ ribonucleotide or to the second 5’ ribonucleotide if the second RNA component is linked to the first 5° ribonucleotide. In an embodiment, the RNA molecule has a modified 5’ or 3’ end, for embodiment by attachment of a lipid group such as cholesterol, or a vitamin such as biotin, or a polypeptide. Such modifications may assist in the uptake of the RNA molecule into the plant cell where the RNA is to function. In an embodiment, the linking ribonucleotide sequence is less than 100 ribonucleotides in length. In an embodiment, the linking ribonucleotide sequence is less than 50 ribonucleotides in length. In an embodiment, the linking ribonucleotide sequence is less than 20 ribonucleotides in length. In an embodiment, the linking ribonucleotide sequence is less than 10 ribonucleotides in length. In an embodiment, the linking ribonucleotide sequence is less than 5 ribonucleotides in length. In an embodiment, the linking ribonucleotide sequence is between 1 and 100 ribonucleotides in length. In an embodiment, the linking ribonucleotide sequence is between 1 and 50 ribonucleotides in length. In an embodiment, the linking ribonucleotide sequence is between 1 and 20 ribonucleotides in length. In an embodiment, the linking ribonucleotide sequence is between 1 and 10 ribonucleotides in length. In an embodiment, the linking ribonucleotide sequence is between 1 and 5 ribonucleotides in length. In an embodiment, the ribonucleotides of the linking ribonucleotide sequence are not basepaired. In a preferred embodiment, the ribonucleotides of the linking ribonucleotide sequence are all basepaired, or all except for 1, 2 or 3 of the ribonucleotides are basepaired. In an embodiment, the first or second RNA component comprises a hairpin structure. In a preferred embodiment, the first and second RNA components each comprise a hairpin structure. In these embodiments, the hairpin structure can be a stem-loop. Accordingly, in an embodiment, the RNA molecule can comprise first and second RNA components which each comprise a hairpin structure, wherein the hairpins are covalently bound by a linker sequence. See, for example, Figure 1. In an embodiment, the linker sequence is one or more unpaired ribonucleic acid(s). In an embodiment, the linker sequence is between 1 and 10 unpaired ribonucleotides. In an embodiment, the RNA molecule has a double hairpin structure i.e. an “ledRNA structure” or “dumbbell structure”. In this embodiment, the first hairpin is the first RNA component and the second hairpin is the second RNA component. In these embodiments, either the first 3’ ribonucleotide and the second 5’ ribonucleotide, or the second 3’ ribonucleotide and the first 5° ribonucleotide, but not both, are covalently joined. In this embodiment, the other 5° / 3’ ribonucleotides can be separated by a nick (i.e. a discontinuity in the dsRNA molecule where there is no phosphodiester bond between the 5° / 3’ ribonucleotides. An embodiment, of this type of arrangement is shown in Figure 1B. In another embodiment, the respective 5 / 3’ ribonucleotides can be separated by a loop. The lengths of the 5° leader and 3” trailer sequences may be the same or different. For embodiment, the 5’ leader may be around 5, 10, 15, 20, 25, 50, 100, 200, 500 ribonucleotides longer than the 3’ trailer sequence or vice versa. In embodiments where the RNA molecule has a double hairpin structure, the second hairpin (in addition to the first hairpin structure) comprises a sense RNA sequence and an antisense RNA sequence that are substantially identical in sequence to a region of a target RNA molecule or its complement, respectively. In an embodiment, each hairpin has a series of ribonucleotides that are substantially identical in sequence to a region of the same target RNA molecule. In an embodiment, each hairpin has a series of ribonucleotides that are substantially identical in sequence to different regions of the same target RNA molecule. In an embodiment, each hairpin has a series of ribonucleotides that are substantially identical in sequence to a region of different target RNA molecules i.e. the RNA molecule can be used to reduce the expression and / or activity of two target RNA molecules which may be unrelated in sequence. In each hairpin of the double hairpin structure of the RNA molecule, the order of the sense and antisense RNA sequences in each hairpin, in 5’ to 3’ order, may independently be either sense then antisense, or antisense then sense. In preferred embodiments, the order of the sense and antisense sequences in the double hairpin structure of the RNA molecule is either antisense-sense-sense-antisense where the two sense sequences are contiguous (Figure 1A), or sense-antisense-antisense-sense where the two antisense sequences are contiguous (Figure 1B). In an embodiment, the RNA molecule can comprise, in 5° to 3” order, a 5° leader sequence, a first loop, a sense RNA sequence, a second loop and a 3’ trailer sequence, wherein the 5” and 3’ leader sequences covalently bond to the sense strand to form a dsRNA sequence. In an embodiment, the 5’ leader and 3’ trailer sequences are not covalently bound to each other. In an embodiment, the 5° leader and 3’ trailer sequences are separated by a nick. In an embodiment, the 5’ leader and 3’ trailer sequences are ligated together to provide a RNA molecule with a closed structure. In another embodiment, the 5° leader and 3’ trailer sequences are separated by a loop. The term “loop” is used in the context of the present disclosure to refer to a loop structure in an RNA molecule disclosed herein that is formed by a series of non- complementary ribonucleotides. Loops generally follow a series of base-pairs between the first and second RNA components or join a sense RNA sequence and an antisense RNA sequence in one or both of the first and second RNA components. In an embodiment, all of the loop ribonucleotides are non-complementary, generally for shorter loops of 4-10 ribonucleotides. In other embodiments, some ribonucleotides in one or more of the loops are complementary and capable of basepairing within the loop sequence, so long as these basepairings enable a loop structure to form. For example, at least 5%, at least 10%, or at least 15% of the loop ribonucleotides are complementary. Embodiments of loops include stem loops or hairpins, psendoknots and tetraloops. In an embodiment, the RNA molecule comprises only two loops, In another embodiment, the RNA molecule comprises at least two, at least three, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, or at least 10 loops, preferably to a maximum of 10 loops. For example, the RNA molecule can comprise 4 loops. Loops of various sizes are contemplated by the present disclosure. For example, loops can comprise 4, 5, 6, 7, 8, 9, 10, 11 or 12 ribonucleotides. In other embodiments, loops comprise 15, 20, 25 or 30 nucleotides. In an embodiment, one or all of the loop sequences are longer than 20 nucleotides. In other embodiments, loops are larger, for example comprising 50, 100, 150, 200 or 300 ribonucleotides. In an embodiment, loops comprise 160 ribonucleotides. In another embodiment, less preferred, loops comprise 200, 500, 700 or 1,000 ribonucleotides provided that the loops do not interfere with the hybridisation of the sense and antisense RNA sequences. In an embodiment, each of the loops have the same number of ribonucleotides. For example, loops can have between 100 and 1,000 ribonucleotides in length. For example, loops can have between 600 and 1,000 ribonucleotides in length. For example, loops can have between 4 and 1,000 ribonucleotides. For example, loops preferably have between 4 and 50 ribonucleotides. In another embodiment, loops comprise differing numbers of ribonucleotides. In another embodiment, one or more loops comprise an intron which can be spliced out of the RNA molecule. In an embodiment, the intron is from a plant gene. Exemplary introns include intron 3 of the maize alcohol dehydrogenase 1 (Adhl) (GenBank: AF044293), intron 4 of the soya beta-conglycinin alpha subunit (GenBank: ABO051865); one of the introns of the pea rbcS-3A gene for the ribulose-1,5- bisphosphate carboxylase (RBC) small subunit (GenBank: X04333). Other embodiments of suitable introns are discussed in (McCullough and Schuler, 1997; Smith et al., 2000). In various embodiments, a loop may be at the end of at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10 consecutive basepairs, which may be canonical basepairs or may include one or more non-canonical basepairs. In another embodiment, the RNA molecule comprises two or more sense ribonucleotide sequences, and antisense ribonucleotide sequences fully based paired thereto, which are each identical in sequence to a region of a target RNA molecule. For example, the RNA molecule can comprise 2, 3,4, 5, 6,7, 8,9, 10, 11, 12 or more sense ribonucleotide sequences, and antisense ribonucleotide sequences fully based paired thereto, which sense ribonucleotide sequences are each independently identical in sequence to a region of a target RNA molecule. In this embodiment, any one or more or all of the sequences can be separated by a linking ribonucleotide sequence(s). In this embodiment, any one or more or all of the sequences can be separated by a loop. In an embodiment, the two or more sense ribonucleotide sequences are identical in sequence to different regions of the same target RNA molecule. For example, the sequences can be identical to at least 2, at least 3, at least 4, at least 5, at least 6 regions of the same target molecule. In another embodiment, the two or more sense ribonucleotide sequences are identical in sequence. In an embodiment, the two or more sense ribonucleotide sequences are identical in sequence to the same region of the same target RNA molecule. In another embodiment, the two or more sense ribonucleotide sequences are identical in sequence to different target RNA molecules. For embodiment, the sequences can be identical to at least 2, at least 3, at least 4, at least 5, at least 6 regions of different target molecules. In another embodiment, the two or more sense ribonucleotide sequences have no intervening loop (spacer) sequences. In an embodiment, the RNA molecule has a single strand of ribonucleotides having a 5’ end, at least one sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully basepaired with each sense ribonucleotide sequence over at least 21 contiguous nucleotides, at least two loop sequences and a 3’ end. In this embodiment, the ribonucleotide at the 5° end and the ribonucleotide at the 3’ end are not directly covalently bonded but are rather positioned adjacent with each basepaired. In another embodiment, consecutive basepairs of RNA components are interspaced by at least one gap. In an embodiment, the “gap” is provided by an unpaired ribonucleotide. In another embodiment, the “gap” is provided by un-ligated 5’ leader sequence and / or 3’ trailer sequence. In this embodiment, the gap can be referred to as an “unligated gap”. Mismatches and unligated gap(s) can be located at various position(s) of the RNA molecule. For embodiment, an unligated gap can immediately follow an antisense sequence. In another embodiment, an unligated gap can be close to a loop of the RNA molecule. In another embodiment, an unligated gap is positioned about equidistant between at least two loops. In an embodiment, the RNA molecule is produced from a single strand of RNA. In an embodiment, the single strand is not circularly closed, for example, comprising an unligated gap. In another embodiment, the RNA molecule is a circularly closed molecule. Closed molecules can be produced by ligating an above referenced RNA molecule comprising an unligated gap, for example with an RNA ligase. In another embodiment, the RNA molecule comprises a 5°- or 3’-, or both, extension sequence. For example, the RNA molecule can comprise a 5° extension sequence which is covalently linked to the first 5° ribonucleotide. In another embodiment, the RNA molecule comprises a 3’ extension sequence which is covalently linked to the second 3’ ribonucleotide. In another embodiment, the RNA molecule comprises a 5’ extension sequence which is covalently linked to the first 5’ ribonucleotide and a 3” extension sequence which is covalently linked to the second 3’ ribonucleotide. In another embodiment, the RNA molecule comprises a 5° extension sequence which is covalently linked to the second 5’ ribonucleotide. In another embodiment, the RNA molecule comprises a 3” extension sequence which is covalently linked to the first 3’ ribonucleotide. In another embodiment, the RNA molecule comprises a 5’ extension sequence which is covalently linked to the second 5’ ribonucleotide and a 3° extension sequence which is covalently linked to the first 3’ ribonucleotide. In another embodiment, the RNA molecule can comprise one or more of the following: 5’ extension sequence which is covalently linked to the first 5° ribonucleotide; 3’ extension sequence which is covalently linked to the second 3’ ribonucleotide; 5’ extension sequence which is covalently linked to the first 5° ribonucleotide and a 3” extension sequence which is covalently linked to the second 3’ ribonucleotide; 5’ extension sequence which is covalently linked to the second 5’ ribonucleotide; 3’ extension sequence which is covalently linked to the first 3’ ribonucleotide; a 5° extension sequence which is covalently linked to the second 5’ ribonucleotide and a 3’ extension sequence which is covalently linked to the first 3’ ribonucleotide. In an example, the RNA molecule comprises a nucleic acid sequence set forth in SEQ ID NO:146 or SEQ ID NO: 147. Non-Canonical Basepairing In an embodiment, RNA molecules of the present invention comprise a sense ribonucleotide sequence and an antisense ribonucleotide sequence which are capable of hybridising to each other to form a double stranded (ds)RNA region with some non- canonical basepairing ie. with a combination of canonical and non-canonical basepairing. In an embodiment, RNA molecules of the present invention comprise two or more sense ribonucleotide sequences which are each capable of hybridising to regions of one (contiguous) antisense ribonucleotide sequence to form a dsRNA region with some non-canonical basepairing. See for example, Figure 1B. In an embodiment, RNA molecules of the present invention comprise two or more antisense sense ribonucleotide sequences which are each capable of hybridising to regions of one (contiguous) sense ribonucleotide sequence to form a dsRNA region with some non- canonical basepairing. See for example, Figure 1A. In an embodiment, RNA molecules of the present invention comprise two or more antisense sense ribonucleotide sequences and two or more sense ribonucleotide sequences wherein each antisense ribonucleotide sequence is capable of hybridising to an antisense ribonucleotide sequence to form two or more dsRNA regions, one or both comprising some non- canonical basepairing. In the following embodiments, the full length of the dsRNA region (i.e. the whole dsRNA region) of the RNA molecule of the invention is considered as the context for the feature if there is only one (contignous) dsRNA region, or for each of the dsRNA regions of the RNA molecule if there are two or more dsRNA regions in the RNA molecule. In an embodiment, at least 5% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, at least 6% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, at least 7% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, at least 8% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, at least 9% or 10% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, at least 11% or 12% of the basepairs in a dsRNA region are non- canonical basepairs. In an embodiment, at least 15% or about 15% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, at least 20% or about 20% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, at least 25% or about 25% of the basepairs in a dsRNA region are non- canonical basepairs. In an embodiment, at least 30% or about 30% of the basepairs in a dsRNA region are non-canonical basepairs. In each of these embodiments, it is preferred that a maximum of 40% of the basepairs in the dsRNA region are non- canonical basepairs, more preferably a maximum of 35% of the basepairs in the dSRNA region are non-canonical basepairs, still more preferably a maximum of 30% of the basepairs in the dsRNA region are non-canonical basepairs. In an embodiment, less preferred, about 35% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, even less preferred, about 40% of the basepairs in a dsRNA region are non-canonical basepairs. In each of the above embodiments, the dsRNA region may or may not comprise one or more non-basepaired ribonucleotides, in either the sense sequence or the antisense sequence, or both. In an embodiment, between 10% and 40% of the basepairs in a dsRNA region of the RNA molecule of the invention are non-canonical basepairs. In an embodiment, between 10% and 35% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, between 10% and 30% of the basepairs in a dsRNA region are non- canonical basepairs. In an embodiment, between 10% and 25% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, between 10% and 20% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, between 10% and 15% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, between 15% and 30% of the basepairs in a dsRNA region are non- canonical basepairs. In an embodiment, between 15% and 25% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, between 15% and 20% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, between 5% and 30% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, between 5% and 25% of the basepairs in a dsRNA region are non- canonical basepairs. In an embodiment, between 5% and 20% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, between 5% and 15% of the basepairs in a dsRNA region are non-canonical basepairs. In an embodiment, between 5% and 10% of the basepairs in a dsRNA region are non-canonical basepairs. In each of the above embodiments, the dsRNA region may or may not comprise one or more non-basepaired ribonucleotides, in either the sense sequence or the antisense sequence, or both. In an embodiment, the dsRNA region of the RNA molecule of the invention comprises 20 contiguous basepairs, wherein at least one basepair of the 20 contiguous basepairs is a non-canonical basepair. In an embodiment, the dsRNA region comprises 20 contiguous basepairs, wherein at least 2 basepairs of the 20 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 20 contiguous basepairs, wherein at least 3 basepairs of the 20 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 20 contiguous basepairs, wherein at least 4 basepairs of the 20 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 20 contiguous basepairs, wherein at least 5 basepairs of the 20 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 20 contiguous basepairs, wherein at least 6 basepairs of the 20 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 20 contiguous basepairs, wherein at least 7 basepairs of the 20 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 20 contiguous basepairs, wherein at least 8 basepairs of the 20 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 20 contiguous basepairs, wherein at least 9 basepairs of the 20 contiguous basepairs are non-canonical basepairs. In each of these embodiments, it is preferred that a maximum of 10 of the 20 contiguous basepairs in the dsRNA region are non-canonical basepairs, more preferably a maximum of 9 of the basepairs in the dsRNA region are non- canonical basepairs, still more preferably a maximum of 8 of the basepairs in the dsRNA region are non-canonical basepairs, even still more preferably a maximum of 7 of the basepairs in the dsRNA region are non-canonical basepairs, and most preferably a maximum of 6 of the basepairs in the dsRNA region are non-canonical basepairs. Preferably, in the above embodiments, the non-canonical basepairs comprise at least one G:U basepair, more preferably all of the non-canonical basepairs are G:U basepairs. Preferably, the features of the above embodiments apply to each and every one of the 20 contiguous basepairs that are present in the RNA molecule of the invention. In an embodiment, the dsRNA region of the RNA molecule of the invention comprises 21 contiguous basepairs, wherein at least one basepair of the 21 contiguous basepairs is a non-canonical basepair. In an embodiment, the dsRNA region comprises 21 contiguous basepairs, wherein at least 2 basepairs of the 21 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 21 contiguous basepairs, wherein at least 3 basepairs of the 21 contiguous basepairs are non-canonical basepairs, In an embodiment, the dsRNA region comprises 21 contiguous basepairs, wherein at least 4 basepairs of the 21 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 21 contiguous basepairs, wherein at least 5 basepairs of the 21 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 21 contiguous basepairs, wherein at least 6 basepairs of the 21 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 21 contiguous basepairs, wherein at least 7 basepairs of the 21 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 21 contiguous basepairs, wherein at least 8 basepairs of the 21 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 21 contiguous basepairs, wherein at least 9 basepairs of the 21 contiguous basepairs are non-canonical basepairs. In each of these embodiments, it is preferred that a maximum of 10 of the 21 contiguous basepairs in the dsRNA region are non-canonical basepairs, more preferably a maximum of 9 of the basepairs in the dsRNA region are non- canonical basepairs, still more preferably a maximum of 8 of the basepairs in the dsRNA region are non-canonical basepairs, even still more preferably a maximum of 7 of the basepairs in the dsRNA region are non-canonical basepairs, and most preferably a maximum of 6 of the basepairs in the dsRNA region are non-canonical basepairs. Preferably, in the above embodiments, the non-canonical basepairs comprise at least one G:U basepair, more preferably all of the non-canonical basepairs are G:U basepairs. Preferably, the features of the above embodiments apply to each and every one of the 21 contiguous basepairs that are present in the RNA molecule of the invention. In an embodiment, the dsRNA region of the RNA molecule of the invention comprises 22 contiguous basepairs, wherein at least one basepair of the 22 contiguous basepairs is a non-canonical basepair. In an embodiment, the dsRNA region comprises 22 contiguous basepairs, wherein at least 2 basepairs of the 22 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 22 contiguous basepairs, wherein at least 3 basepairs of the 22 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 22 contiguous basepairs, wherein at least 4 basepairs of the 22 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 22 contiguous basepairs, wherein at least 5 basepairs of the 22 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 22 contiguous basepairs, wherein at least 6 basepairs of the 22 contiguous basepairs are non-canonical basepairs, In an embodiment, the dsRNA region comprises 22 contiguous basepairs, wherein at least 7 basepairs of the 22 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 22 contiguous basepairs, wherein at least 8 basepairs of the 22 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 22 contiguous basepairs, wherein at least 9 basepairs of the 22 contiguous basepairs are non-canonical basepairs. In each of these embodiments, it is preferred that a maximum of 10 of the 22 contiguous basepairs in the dsRNA region are non-canonical basepairs, more preferably a maximum of 9 of the basepairs in the dsRNA region are non- canonical basepairs, still more preferably a maximum of 8 of the basepairs in the dsRNA region are non-canonical basepairs, even still more preferably a maximum of 7 of the basepairs in the dsRNA region are non-canonical basepairs, and most preferably a maximum of 6 of the basepairs in the dsRNA region are non-canonical basepairs. Preferably, in the above embodiments, the non-canonical basepairs comprise at least one G:U basepair, more preferably all of the non-canonical basepairs are G:U basepairs. Preferably, the features of the above embodiments apply to each and every one of the 22 contiguous basepairs that are present in the RNA molecule of the invention. In an embodiment, the dsRNA region of the RNA molecule of the invention comprises 23 contiguous basepairs, wherein at least one basepair of the 23 contiguous basepairs is a non-canonical basepair. In an embodiment, the dsRNA region comprises 23 contiguous basepairs, wherein at least 2 basepairs of the 23 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 23 contiguous basepairs, wherein at least 3 basepairs of the 23 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 23 contiguous basepairs, wherein at least 4 basepairs of the 23 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 23 contiguous basepairs, wherein at least 5 basepairs of the 23 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 23 contiguous basepairs, wherein at least 6 basepairs of the 23 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 23 contiguous basepairs, wherein at least 7 basepairs of the 23 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 23 contiguous basepairs, wherein at least 8 basepairs of the 23 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 23 contiguous basepairs, wherein at least 9 basepairs of the 23 contiguous basepairs are non-canonical basepairs. In each of these embodiments, it is preferred that a maximum of 10 of the 23 contiguous basepairs in the dsRNA region are non-canonical basepairs, more preferably a maximum of 9 of the basepairs in the dsRNA region are non- canonical basepairs, still more preferably a maximum of 8 of the basepairs in the dsRNA region are non-canonical basepairs, even still more preferably a maximum of 7 of the basepairs in the dsRNA region are non-canonical basepairs, and most preferably a maximum of 6 of the basepairs in the dsRNA region are non-canonical basepairs. Preferably, in the above embodiments, the non-canonical basepairs comprise at least one G:U basepair, more preferably all of the non-canonical basepairs are G:U basepairs. Preferably, the features of the above embodiments apply to each and every one of the 23 contiguous basepairs that are present in the RNA molecule of the invention. In an embodiment, the dsRNA region of the RNA molecule of the invention comprises 24 contiguous basepairs, wherein at least one basepair of the 24 contiguous basepairs is a non-canonical basepair. In an embodiment, the dsRNA region comprises 24 contiguous basepairs, wherein at least 2 basepairs of the 24 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 24 contiguous basepairs, wherein at least 3 basepairs of the 24 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 24 contiguous basepairs, wherein at least 4 basepairs of the 24 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 24 contiguous basepairs, wherein at least 5 basepairs of the 24 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 24 contiguous basepairs, wherein at least 6 basepairs of the 24 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 24 contiguous basepairs, wherein at least 7 basepairs of the 24 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 24 contiguous basepairs, wherein at least 8 basepairs of the 24 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 24 contiguous basepairs, wherein at least 9 basepairs of the 24 contiguous basepairs are non-canonical basepairs. In each of these embodiments, it is preferred that a maximum of 10 of the 24 contiguous basepairs in the dsRNA region are non-canonical basepairs, more preferably a maximum of 9 of the basepairs in the dsRNA region are non- canonical basepairs, still more preferably a maximum of 8 of the basepairs in the dsRNA region are non-canonical basepairs, even still more preferably a maximum of 7 of the basepairs in the dsRNA region are non-canonical basepairs, and most preferably a maximum of 6 of the basepairs in the dsRNA region are non-canonical basepairs. Preferably, in the above embodiments, the non-canonical basepairs comprise at least one G:U basepair, more preferably all of the non-canonical basepairs are G:U basepairs. Preferably, the features of the above embodiments apply to each and every one of the 24 contiguous basepairs that are present in the RNA molecule of the invention. In the following embodiments, the full length of the dsRNA region (i.e. the whole dsRNA region) of the RNA molecule of the invention is considered as the context for the feature if there is only one (contiguous) dsRNA region, or for each of the dsRNA regions of the RNA molecule if there are two or more dsRNA regions in the RNA molecule. In an embodiment, the dsRNA region does not comprise 20 contiguous canonical basepairs i.e. every subregion of 20 contiguous basepairs includes at least one non-canonical basepair, preferably at least one G:U basepair. In an embodiment, the dsRNA region does not comprise 19 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 18 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 17 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 16 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 15 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 14 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 13 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 12 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 11 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 10 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 9 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 8 contiguous canonical basepairs. In an embodiment, the dsRNA region does not comprise 7 contiguous canonical basepairs. In the above embodiments, it is preferred that the longest subregion of contiguous canonical basepairing in the dsRNA region of the RNA molecule, or each and every dsRNA region in the RNA molecule, is 5, 6 or 7 contiguous canonical basepairs i.e. towards the shorter lengths mentioned. Each of the features of the above embodiments is preferably combined in the RNA molecule with the following features. In an embodiment, the dsRNA region comprises between 10 and 19 or 20 contiguous basepairs. In a preferred embodiment, the dsRNA region comprises between 12 and 19 or 20 contiguous basepairs. In an embodiment, the dsRNA region comprises between 14 and 19 or 20 contiguous basepairs. In these embodiments, the dsRNA region comprises 15 contiguous basepairs. In an embodiment, the dsRNA region comprises 16, 17, 18 or 19 contiguous basepairs. In an embodiment, the dsRNA region comprises 20 contiguous basepairs. Preferably, in the above embodiments, the contiguous basepairs comprise at least one non-canonical basepair which comprises at least one G:U basepair, more preferably all of the non- canonical basepairs in the region of contiguous basepairs are G:U basepairs. In an embodiment, the dsRNA region comprises a subregion of 4 canonical basepairs flanked by non-canonical basepairs, i.e. at least one, preferably one or two (not more than 2), non-canonical basepairs adjacent to each end of the 4 canonical basepairs. In an embodiment, the dsRNA region comprises 2 subregions each of 4 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 3 subregions each of 4 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 4 or 5 subregions each of 4 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 6 or 7 subregions each of 4 canonical basepairs flanked by non- canonical basepairs. In an embodiment, the dsRNA region comprises 8 to 10 subregions each of 4 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 11 to 15 subregions each of 4 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 50 subregions each of 4 canonical basepairs flanked by non- canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 40 subregions each of 4 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 30 subregions each of 4 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 20 subregions each of 4 canonical basepairs flanked by non-canonical basepairs. Preferably, in the above embodiments, the non-canonical basepairs comprise at least one G:U basepair, more preferably all of the non-canonical basepairs flanking the contiguous canonical basepairs in the subregions are G:U basepairs. In variations of the above embodiments, one or both of the flanking non- canonical basepairs are replaced with a non-basepaired ribonucleotide in the sense sequence, the antisense sequence or in both sequences, for some or all of the subregions. It is readily understood that, in the above embodiments, the maximum number of subregions is determined by the length of the dsRNA region in the RNA molecule. In an embodiment, the dsRNA region comprises a subregion of 5 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 2 subregions each of 5 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 3 subregions each of 5 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 4 or 5 subregions each of 5 canonical basepairs flanked by non- canonical basepairs. In an embodiment, the dsRNA region comprises 6 or 7 subregions each of 5 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 8 to 10 subregions each of 5 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 11 to 15 subregions each of 5 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 50 subregions each of 5 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 50 subregions each of 5 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 30 subregions each of 5 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 20 subregions each of 5 canonical basepairs flanked by non-canonical basepairs. Preferably, in the above embodiments, the non-canonical basepairs comprise at least one G:U basepair, more preferably all of the non-canonical basepairs flanking the contiguous canonical basepairs in the subregions are G:U basepairs. In variations of the above embodiments, one or both of the flanking non-canonical basepairs are replaced with a non-basepaired ribonucleotide in the sense sequence, the antisense sequence or in both sequences, for some or all of the subregions. It is readily understood that, in the above embodiments, the maximum number of subregions is determined by the length of the dsRNA region in the RNA molecule. In an embodiment, the dsRNA region comprises a subregion of 6 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 2 subregions each of 6 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 3 subregions each of 6 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 4 or 5 subregions each of 6 canonical basepairs flanked by non- canonical basepairs. In an embodiment, the dsRNA region comprises 6 or 7 subregions each of 6 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 8 to 10 subregions each of 6 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises 11 to 16 subregions each of 6 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 60 subregions each of 6 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 60 subregions each of 6 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 30 subregions each of 6 canonical basepairs flanked by non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 20 subregions each of 6 canonical basepairs flanked by non-canonical basepairs. Preferably, in the above embodiments, the non-canonical basepairs comprise at least one G:U basepair, more preferably all of the non-canonical basepairs flanking the contiguous canonical basepairs in the subregions are G:U basepairs. In variations of the above embodiments, one or both of the flanking non-canonical basepairs are replaced with a non-basepaired ribonucleotide in the sense sequence, the antisense sequence or in both sequences, for some or all of the subregions. It is readily understood that, in the above embodiments, the maximum number of subregions is determined by the length of the dsRNA region in the RNA molecule. In an embodiment, the dsRNA region comprises a subregion of 10 contiguous basepairs wherein 2-4 of the basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 2 subregions each of 10 contiguous basepairs wherein 2-4 of the 10 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 3 subregions each of 10 contiguous basepairs wherein 2-4 of the 10 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 4 subregions each of 10 contiguous basepairs wherein 2-4 of the 10 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 5 subregions each of 10 contiguous basepairs wherein 2-4 of the 10 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 10 subregions each of 10 contiguous basepairs wherein 2-4 of the 10 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises 4 subregions each of 15 contiguous basepairs wherein 2-6 of the 15 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 50 subregions each of 10 contiguous basepairs wherein 2-4 of the 10 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 40 subregions each of 10 contiguous basepairs wherein 2-4 of the 10 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 30 subregions each of 10 contiguous basepairs wherein 2-4 of the 10 contiguous basepairs are non-canonical basepairs. In an embodiment, the dsRNA region comprises between 2 and 20 subregions each of 10 contiguous basepairs wherein 2-4 of the 10 contiguous basepairs are non-canonical basepairs. In an embodiment, the non-canonical basepairs in one (contiguous) or more, or all dsRNA regions of the RNA molecule are not adjacent a non-base pair. In another embodiment, the non-canonical basepairs are at least 2 continguous base pairs from a non-base pair. In another embodiment, the non- canonical basepairs are at least 3, 4, 5, 6, 7, 8, 9, 10 or more continguous base pairs from a non-base pair. In an embodiment the non-canonical basepairs in one (contiguous) or more, or all dsRNA regions of the RNA molecule are not adjacent a loop sequence. In another embodiment, the non-canonical basepairs are at least 2 continguous base pairs from a loop sequence. In another embodiment, the non- canonical basepairs are at least 3, 4, 5, 6, 7, 8, 9, 10 or more continguous base pairs from a loop sequence. Preferably, in the above embodiments, the non-canonical basepairs comprise at least one G:U basepair, more preferably all of the non-canonical basepairs in the subregions are G:U basepairs. In variations of the above embodiments, one or more of the 2-4 or 2-6 non-canonical basepairs are replaced with a non- basepaired ribonucleotide in the sense sequence, the antisense sequence or in both sequences, for some or all of the subregions. It is readily understood that, in the above embodiments, the maximum number of subregions is determined by the length of the dsRNA region in the RNA molecule. In an embodiment, the ratio of canonical to non-canonical basepairs in the dsRNA region is between 2.5:1 and 3.5:1, for example about 3:1. In an embodiment, the ratio of canonical to non-canonical basepairs in the dsRNA region is between 3.5:1 and 4.5:1, for example about 4:1. In an embodiment, the ratio of canonical to non- canonical basepairs in the dsRNA region is between 4.5:1 and 5.5:1, for example about 5:1. In an embodiment, the ratio of canonical to non-canonical basepairs in the dsRNA region is between 5.5:1 and 6.5:1, for example about 6:1. Different dsRNA regions in the RNA molecule may have different ratios. In the above embodiments, the non-canonical basepairs in the dsRNA region(s) of the RNA molecule are preferably all G:U basepairs. In an embodiment, at least 99% of the non-canonical basepairs are G:U basepairs. In an embodiment, at least 98% of the non-canonical basepairs are G:U basepairs. In an embodiment, at least 97% of the non-canonical basepairs are G:U basepairs. In an embodiment, at least 95% of the non- canonical basepairs are G:U basepairs. In an embodiment, at least 90% of the non- canonical basepairs are G:U basepairs. In an embodiment, between 90 and 95% of the non-canonical basepairs are G:U basepairs. For example, if there are 10 non-canonical basepairs, at least 9 (90%) are G:U basepairs. In another embodiment, between 3% and 50% of the non-canonical basepairs are G:U basepairs. In another embodiment, between 5% and 30% of the non-canonical basepairs are G:U basepairs. In another embodiment, between 10% and 30% of the non-canonical basepairs are G:U basepairs. In another embodiment, between 15% and 20% of the non-canonical basepairs are G:U basepairs. In an example of the above embodiments, there are at least 3 G:U base pairings in one (contiguous) or more, or all dsRNA regions of the RNA molecule. In another example, there are at least 4, 5, 6, 7, 8, 9 or 10 G:U base pairings. In another example, there are at least between 3 and 10 G:U base pairings. In another example, there are at least between 5 and 10 G:U base pairings. The dsRNA region comprising non-canonical basepairing(s) comprises an antisense sequence of 20 contiguous nucleotides which acts as an antisense regulatory element. In an embodiment, the antisense regulatory element is at least 80%, preferably at least 90%, more preferably at least 95% or most preferably 100% complementary to a target RNA molecule in a plant cell. In an embodiment, a dsRNA region comprises 2, 3, 4, or 5 antisense regulatory elements which either are complementary to the same target RNA molecule (i.e. to different regions of the same target RNA molecule) or are complementary to different target RNA molecules. In an embodiment, one or more ribonucleotides of the sense ribonucleotide sequence or one or more ribonucleotides of the antisense ribonucleotide sequence, or both, are not basepaired in the dsRNA region when the sense and antisense sequences hybridize. In this embodiment, the dsRNA region does not include any loop sequence which covalently joins the sense and antisense sequences. One or more ribonucleotides of a dsRNA region or subregion may not be basepaired. Accordingly, in this embodiment, the sense strand of the dsRNA region does not fully basepair with its corresponding antisense strand. In an embodiment, the chimeric RNA molecule does not comprise a non- canonical base pair at the base of a loop of the molecule. In another embodiment, one, two, three, four, five or more or all of the non-canonical base pairs are flanked by canonical base pairs. In an embodiment, the chimeric RNA molecule comprises at least one plant DCL-1 cleavage site. In an embodiment, the target RNA molecule is not a viral RNA molecule. In an embodidment, the target RNA molecule is not a South African cassava mosaic virus RNA molecule. In an embodiment, the chimeric RNA molecule comprises at least one non- basepair, or stretch of non-pasepairs, flanked by canonical base pairs, non-canonical base pairs, or a canonical base pair and a non-canonical base pair. For example, this may be a bulge as described herein. In an embodiment, the chimeric RNA molecule does not comprise a double stranded region with greater than 11 canonical base pairs. Moreover, in an embodiment and optionally in combination with any of the features of the above embodiments, the total number of ribonucleotides in the sense sequence(s) and the total number of ribonucleotides in the antisense sequence(s) may not be identical, although preferably they are identical. In an embodiment, the total number of ribonucleotides in the sense ribonucleotide sequence(s) of the dsRNA region is between 90% and 110% of the total number of ribonucleotides in the antisense ribonucleotide sequence(s). In an embodiment, the total number of ribonucleotides in the sense ribonucleotide sequence(s) is between 95% and 105% of the total number of ribonucleotides in the antisense ribonucleotide sequence(s). In an embodiment, chimeric RNA molecules of the present disclosure can comprise one or more structural elements such as internal or terminal bulges or loops. Various embodiments of bulges and loops are discussed above. In an embodiment, dsRNA regions are separated by a structural element such as a bulge or loop. In an embodiment, dsRNA regions are separated by a intervening (spacer) sequence. Some of the ribonucleotides of the spacer sequence may be basepaired to other ribonucleotides in the RNA molecule, for example to other ribonucleotides within the spacer sequence, or they may not be basepaired in the RNA molecule, or some of each. In an embodiment, dsRNA regions are linked to a terminal loop. In an embodiment, dsRNA regions are flanked by terminal loops. In an embodiment, where the dsRNA region of the RNA molecule of the invention has at least 3 non-canonical basepairs in any subregion of 5 contiguous basepairs, the non-canonical basepairs are not contiguous but are separated by one or more canonical basepairs i.e. the dsRNA region does not have 3 or more contiguous non-canonical basepairs. In an embodiment, the dsRNA region does not have 4 or more contiguous non-canonical basepairs. For example, in an embodiment, the dsRNA region comprises at least 3 non-canonical basepairs in a subregion of 10 basepairs, wherein each non-canonical basepair is separated by 4 canonical basepairs. In an embodiment, an RNA molecule of the invention comprises more than one dsRNA region. For example, the RNA molecule comprises 2, 3,4, 5, 6,7, 8,9, 10 or more dsRNA regions. In this example, one or more or all of the dsRNA regions can comprise above exemplified properties such as non-canonical basepairing and / or number of antisense regulatory elements. Silencing Activity RNA molecules of the present disclosure have antisense activity as they comprise a sense ribonucleotide sequence that is essentially complementary to a region of a target RNA molecule. For example, the ribonucleotide sequence is essentially complementary to a region of a target RNA molecule in a plant cell. Such components of the RNA molecules defined herein can be referred to as an “antisense regulatory element”. “Essentially complementary” means that the sense ribonucleotide sequence may have insertions, deletions and individual point mutations in comparison with the complement of the target RNA molecule in the plant cell. Preferably, the homology is at least 80%, preferably at least 90%, preferably at least 95%, most preferably 100%, between the sense ribonucleotide sequence with antisense activity and the target RNA molecule. For example, the sense ribonucleotide sequence can comprise about 15, about 16, about 17, about 18, about 19 or more contiguous nucleotides that are identical in sequence to a first region of a target RNA molecule in a plant cell. In another example, the sense ribonucleotide sequence can comprise about 20 contiguous nucleotides that are identical in sequence to a first region of a target RNA molecule in a plant cell. “Antisense activity” is used in the context of the present disclosure to refer to an antisense regulatory element from an RNA molecule defined herein that modulates (increase or decrease) expression of a target RNA molecule. In various examples, antisense regulatory elements according to the present disclosure can comprise a plurality of monomeric subunits linked together by linking groups. Examples include primers, probes, antisense compounds, antisense oligonucleotides, external guide sequence (EGS) oligonucleotides, alternate splicers, gapmers, siRNAs and microRNAs. As such, RNA molecules according to the present disclosure can comprise antisense regulatory elements with single-stranded, double- stranded, circular, branched or hairpin structures. In an example, the antisense sequence can contain structural elements such as internal or terminal bulges or loops. In an example, RNA molecules of the present disclosure comprise chimeric oligomeric components such as chimeric oligonucleotides. For example, an RNA molecule can comprise differently modified nucleotides, mixed-backbone antisense oligonucleotides or a combination thereof. In an example, chimeric oligomeric compounds can comprise at least one region modified so as to confer increased resistance to nuclease degradation, increased cellular uptake, and / or increased binding affinity for the target RNA molecule. Antisense regulatory elements can have a variety of lengths. Across various examples, the present disclosure provides antisense regulatory elements consisting of X-Y linked bases, where X and Y are each independently selected from 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, and 50 (provided that X<Y). For example, in certain embodiments, the present disclosure provides antisense regulatory elements comprising: 8-9, 8-10, 8-11, 8-12, 8-13, 8-14, 8-15, 8-16, 8-17, 8-18, 8-19, 8- 20, 8-21, 8-22, 8-23, 8-24, 8-25, 8-26, 8-27, 8-28, 8-29, 8-30, 9-10, 9-11, 9-12, 9-13, 9- 14,9-15, 9-16, 9-17, 9-18, 9-19, 9-20, 9-21, 9-22, 9-23, 9-24, 9-25, 9-26, 9-27, 9-28, 9- 29, 9-30, 10-11, 10-12, 10-13, 10-14, 10-15, 10-16, 10-17, 10-18, 10-19, 10-20, 10-21, 10-22, 10-23, 10-24, 10-25, 10-26, 10-27, 10-28, 10-29, 10-30, 11-12, 11-13, 11-14, 11-15, 11-16, 11-17, 11-18, 11-19, 11-20, 11-21, 11-22, 11-23, 11-24, 11-25, 11-26, 11-27, 11-28, 11-29, 11-30, 12-13, 12-14, 12-15, 12-16, 12-17, 12-18, 12-19, 12-20, 12-21, 12-22, 12-23, 12-24, 12-25, 12-26, 12-27, 12-28, 12-29, 12-30, 13-14, 13-15, 13-16, 13-17, 13-18, 13-19, 13-20, 13-21, 13-22, 13-23, 13-24, 13-25, 13-26, 13-27, 13-28, 13-29, 13-30, 14-15, 14-16, 14-17, 14-18, 14-19, 14-20, 14-21, 14-22, 14-23, 14-24, 14-25, 14-26, 14-27, 14-28, 14-29, 14-30, 15-16, 15-17, 15-18, 15-19, 15-20, 15-21, 15-22, 15-23, 15-24, 15-25, 15-26, 15-27, 15-28, 15-29, 15-30, 16-17, 16-18, 16-19, 16-20, 16-21, 16-22, 16-23, 16-24, 16-25, 16-26, 16-27, 16-28, 16-29, 16-30, 17-18, 17-19, 17-20, 17-21, 17-22, 17-23, 17-24, 17-25, 17-26, 17-27, 17-28, 17-29, 17-30, 18-19, 18-20, 18-21, 18-22, 18-23, 18-24, 18-25, 18-26, 18-27, 18-28, 18-29, 18-30, 19-20, 19-21, 19-22, 19-23, 19-24, 19-25, 19-26, 19-29, 19-28, 19-29, 19-30, 20-21, 20-22, 20-23, 20-24, 20-25, 20-26, 20-27, 20-28, 20-29, 20-30, 21-22, 21-23, 21-24, 21-25, 21-26, 21-27, 21-28, 21-29, 21-30, 22-23, 22-24, 22-25, 22-26, 22-27, 22-28, 22-29, 22-30, 23-24, 23-25, 23-26, 23-27, 23-28, 23-29, 23-30, 24-25, 24-26, 24-27, 24-28, 24-29, 24-30, 25-26, 25-27, 25-28, 25-29, 25-30, 26-27, 26-28, 26-29, 26-30, 27-28, 27-29, 27-30, 28-29, 28-30, or 29-30 linked bases. RNA molecules according to the present disclosure can comprise multiple antisense regulatory elements. For example, RNA molecules can comprise at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10 antisense regulatory elements. In an example, the antisense regulatory elements are the same. In this example, the RNA molecule can comprise at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10 copies of an antisense regulatory element. In another example, RNA molecules according to the present disclosure can comprise different antisense regulatory elements. For example, antisense regulatory elements may be provided to target multiple genes in a pathway such as lipid biosynthesis. In this example, the RNA molecule can comprise at least 2, at least 3, at least 4, at least 5, at least 6, at least 7, at least 8, at least 9, at least 10 different antisense regulatory elements. Antisense sequences according to the present disclosure can modulate, preferably decrease, expression or amount of various target RNA molecules. In an example, the target RNA molecule modulates flowering in a plant disclosed herein. Examples of such target RNA molecules are described in the art (e.g. Cockram et al., 2007; Chen et al., 2009; Jung and Muller., 2009; Cho et al., 2017). In an example, the target RNA molecule modulates vernalisation in a plant disclosed herein. In an example, the target RNA molecule promotes early flowering. In another example, the target RNA molecule promotes late flowering. In an example, the target RNA molecule encodes a plant polycomb group (PcG) protein. In an example, the target RNA molecule encodes VERNALIZATION1 (VRN1; UniProt accession number: Q8L3W1) or VERNALIZATION2 (VRN2; UniProt accession number: Q8W35B1) or homologous genes in other species. In an example, the target RNA molecule encodes a PcG from Arabidopsis, corn, canola, cotton, soybean, alfalfa, lettuce, wheat, barley, rice, legume, Medicago truncatula, sugarbeet or rye. In an example, the target RNA molecule encodes a PcG from Arabidopsis, corn, canola, cotton, soybean, wheat, barley, rice, legume, Medicago truncatula, sugarbeet or rye. In an example, the target RNA molecule encodes VRN1 and / or VRN2 from wheat. In an example, the target RNA molecule encodes EMBRYONIC FLOWER2 (EMF2; UniProt accession number: Q8L6Y4) or FERTILIZATION INDEPENDENT SEED2 (FIS2; UniProt accession number: PODKJ7) or homologous genes in other species. In an example, the target RNA molecule encodes one or more or all of VRN1, VRN2, EMF2, FIS2. Other examples of target RNA molecules encode EARLYINSHORTDAYS4 (ESD4; UniProt accession number: Q94F30) and FLOWERING LOCUS T (FLT; UniProt accession number: Q9SXZ2) or homologous genes in other species. Accordingly, in various examples, the target RNA molecules can be a gene transcript of one or more of VRNI, VRN2, EMF2, FIS2, ESD4, FLTI, FLT2. In an example, the target RNA molecule can be a gene transcript of one or more of the following from wheat / barley, VRNI1 / VRN-Al (KR422423.1); VRN2 (ZCCT1, TaVRN-2B) (AAS58481.1); FT (AY705794.1). In another example, the target RNA molecule can be a gene transcript of one or more of the following from canola, BnFLC1 (AY036888, Bna.FLC.A10, BnaA10g22080D); BnFLC2 (AY036889); BnFLC3 (AY036890); BnFLC4 (AY036891); BnFLC5 (AY036892); BnFRI (BnaA03g13320D); BnFT (BnaA02g12130D). For example, the target RNA molecule can be a gene transcript of BnFLC1 (AY036888, Bna.FLC.A10, BnaA10g22080D). In an example, the target RNA molecule can be a gene transcript of a FRIGIDA orthologue such as BnaA3.FRI (Yi et al., 2018) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from Arabidopsis, FRI (AT4G00650); FLC (AT5G10140); VRN1 (AT3G18990); VRN2 (AT4G16845); VIN3 (AT5G57380); FT (AT1G65480); SOC1 (AT2G45660); CO (constans) (AT5G15840); LFY (AT5G61850); AP1 (AT1G69120) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from Rice, OsPhyB (OSNPB_030309200); OsCol4 (Hd-1) (HC084637); RFT1 (OSNPB_070486100); OsSNB (OSNPB_070235800); OsIDS1 (Os03g0818800); OsGI (OSNPB_010182600) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from Medicago truncatula, MtFTal (HQ721813); MtFTb1 (HQ721815) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of a homolog of one or more of the following from Legume, MtFTal; MtFTbl. In another example, the target RNA molecule can be a gene transcript of one or more of the following from Sugarbeet, chard, turnip, BTCI (HQ709091.); BvFTI (HM448909.1); BvFLI (DQ189214., DQ189215.) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from barley, HYVRN1 (AY896051); HYVRN2 (AY687931, AY485978); HVFT (DQ898519) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from Maize, ZmMADS1 / ZmM5 (LOCS542042, HM993639); PHYAl (AY234826); PHYA2 (AY260865); PHYB1 (AY234827); PHYB2 (AY234828); PHYC1 (AY234829); PHYC2 (AY234830); LD (AF166527); ZFL1 (AY179882); ZFL2 (AY179881); DWARFS (AF413203); AN1 (L37750); ID1 (AF058757); ZCN8 (LOC100127519) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from Brassica rapa, BrFLC2 (AHO012704); BrFT (Bra004928); BrFRI (HQ615935) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of MSFRI-L (JX173068) from Alfalfa (Medicago sativa) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from Barrell medic, MtYFL (BT053010); MtSOCla (Medtr07g075870); MtSOC1b (Medtr08g033250); MtSOClc (Medtr08g033220); MtFTal (HQ721813) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from cotton, GhCO (Gorai.008G059900); GhFLC (Gorai.013G069000); GhFRI (Gorai.003G118000); GhFT (Gorai.004G264600); GhLFY (Gorai.001G053900); GhPHYA (Gorai.007G292800, Gorai.013G203900); GhPHYB (Gorai.011G200200); GhSOC1 (Gorai.008G115200); GhVRN1 (Gorai.002G006500, Gorai.005G240900, Gorai.012G150900, Gorai.013G040000); GhVRN2 (Gorai.003G176300); GhVRNS5 (Gorai.009G023200) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from onion, AcGI (GQ232756); AcFKF (GQ232754); AcZTL (GQ232755); AcCOL (GQ232751); AcFTL (CF438000); AcFT1 (KC485348); AcFT2 (KC485349); AcFT6 (KC485353); AcPHYA (GQ232753); AcCOP1 (CF451443) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from Asparagus officinalis, FPA (LOC109824259, LOC109840062); TWIN SISTER of FT-like (LOC109835987); MOTHER of FT (LOC109844838); FCA-like (LOC109841154, LOC109821266); PHOTOPERIOD- INDEPENDENT EARLY FLOWERING 1 (LOC109834006); FLOWERING LOCUS T-like (LOC109830558, LOC109825338, LOC109824462); Flowering locus K (LOC109847537); Flowering time control protein FY (LOC109844014); flowering time control protein FCA-like (LOC109842562) or homologous genes in other species. In another example, the target RNA molecule can be a gene transcript of one or more of the following from lettuce, LsFT (LOC111907824); TFL1-like (LOC111903066); TFL1 homolog 1-like (LOC111903054); LsFLC (LOC111876490, JI588382); SOC1- like (LOC111912847, LOC111880753, LOC111878575); TsLFY (LC164345.1, XM_023888266.1) or homologous genes in other species. Those of skill in the art will appreciate that many of the above referenced gene transcripts and proteins encoded by the same are conserved amongst related crop species. Accordingly, in an example, the present disclosure extends to homologues thereof. Identifying homologues is considered well within the purview of those skilled in the art using various online databases such as Genbank, EMBL-EBI, Ensembl Plants or performing online searches using tools such as nucleotide BLAST. Examples of homologues are provided above. Accordingly, in a preferred example, the target RNA molecule can be a gene transcript of BnFLCI or a homolog thereof such as, for example BnFLC1 (AY036888), BnFLC1 (Bna.FLC.A10) or BnFLC1 (BnaA10g22080D). In another example, the target RNA is a non-coding RNA that modulates flowering in plants. In an example, the non-coding RNA is a miRNA or pre-cursor thereof. In an example, the target miRNA is a miRNA from the miR-156 family or a precursor thereof. For example, the target RNA can be any one or more of miR-156a, miR-156b, miR-156c, miR-156d, miR-156e, miR-156f, miR-156g, miR-156h or a precursor thereof. In an example, the target RNA is one or more of miR-156a, miR- 156b, miR-156c or a precursor thereof. In an example, the target RNA is miR-172 or a precursor thereof. Other exemplary target RNAs which are miRNAs or precursors thereof are described in Teotia and Tang., 2015). miRNA sequences are described in the art and can be identified by for example miRBase: the microRNA database (Kozomara et al., 2019); www dot mirbase dot org). In a preferred example, the target RNA molecule is a transcript from a VRN2 gene. Nucleic Acids Encoding RNA Molecules One of skill in the art will appreciate from the foregoing description that the present disclosure also provides an isolated nucleic acid encoding RNA molecules disclosed herein and the component parts thereof. For example, a nucleic acid comprising a sequence set forth in any one or more of SEQ ID NO:1, SEQ ID NO:2, SEQ ID NO:3, SEQ ID NO:4, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO:9, SEQ ID NO:150. The nucleic acid may be partially purified after expression in a host cell. The term "partially purified " is used to refer to an RNA molecule that has generally been separated from the lipids, nucleic acids, other peptides, and other contaminating molecules with which it is associated in a host cell. Preferably, the partially purified polynucleotide is at least 60% free, more preferably at least 75% free, and more preferably at least 90% free from other components with which it is associated. In another example, a polynucleotide according to the present disclosure is a heterologous polynucleotide. ~The term "heterologous polynucleotide” is well understood in the art and refers to a polynucleotide which is not endogenous to a cell, or is a native polynucleotide in which the native sequence has been altered, or a native polypeptide whose expression is quantitatively altered as a result of a manipulation of the cell by recombinant DNA techniques. In another example, a polynucleotide according to the present disclosure is a synthetic polynucleotide. For example, the polynucleotide may be produced using techniques that do not require pre-existing nucleic acid sequences such as DNA printing and oligonucleotide synthesis. In another example, the polynucleotide is produced from xeno nucleic acids. In an example, a polynucleotide disclosed herein which encodes an RNA precursor molecule comprising an intron, preferably in a 5° extension sequence or in at least one loop sequence, wherein the intron is capable of being spliced out during transcription of the polynucleotide in a host cell or in vitro. In another example, the loop sequence comprises two, three, four, five or more introns. The present disclosure also provides an expression construct such as a DNA construct comprising an isolated nucleic acid of the disclosure operably linked to a promoter. In an example, such isolated nucleic acids and / or expression constructs are provided in a cell or plant. In an example isolated nucleic acids are stably integrated into the genome of the cell or plant organism. Various examples of suitable expression constructs, promoters and cells comprising the same are discussed below. Synthesis of RNA molecules according to the present disclosure can be achieved using various methods known in the art. The Examples section provides an example of in vitro synthesis. In this example, constructs comprising RNA molecules disclosed herein are restricted at the 3° end, precipitated, purified and quantified. RNA synthesis can be achieved in bacterial culture following transformation of HT115 electro competent cells and induction of RNA synthesis using the T7, IPTG system. Recombinant Vectors One embodiment of the present invention includes a recombinant vector, which comprises at least one RNA molecule defined herein and is capable of delivering the RNA molecule into a host cell. Recombinant vectors include expression vectors. Recombinant vectors contain heterologous polynucleotide sequences, that is, polynucleotide sequences that are not naturally found adjacent to an RNA molecule defined herein, that preferably, are derived from a different species. The vector can be either RNA or DNA, and typically is a viral vector, derived from a virus, or a plasmid. Various viral vectors can be used to deliver and mediate expression of an RNA molecule according to the present disclosure. The choice of viral vector will generally depend on various parameters, such as the cell or tissue targeted for delivery, transduction efficiency of the vector and pathogenicity. In an example, the viral vector integrates into host cellular chromatin (e.g. lentiviruses). In another example, the viral vector persists in the cell nucleus predominantly as an extrachromosomal episome (e.g. adenoviruses). Examples of these types of viral vectors include oncoretroviruses, lentiviruses, adeno-associated virus, adenoviruses, herpes viruses and retroviruses. Plasmid vectors typically include additional nucleic acid sequences that provide for easy selection, amplification, and transformation of the expression cassette in prokaryotic cells, e.g., pUC-derived vectors, pGEM-derived vectors or binary vectors containing one or more T-DNA regions. Additional nucleic acid sequences include origins of replication to provide for autonomous replication of the vector, selectable marker genes, preferably encoding antibiotic or herbicide resistance, unique multiple cloning sites providing for multiple sites to insert nucleic acid sequences or genes encoded in the nucleic acid construct, and sequences that enhance transformation of plant cells. "Operably linked" as used herein, refers to a functional relationship between two or more nucleic acid (e.g., DNA) segments. Typically, it refers to the functional relationship of a transcriptional regulatory element (promoter) to a transcribed sequence. For example, a promoter is operably linked to a coding sequence of an RNA molecule defined herein, if it stimulates or modulates the transcription of the coding sequence in an appropriate cell. Generally, promoter transcriptional regulatory elements that are operably linked to a transcribed sequence are physically contiguous to the transcribed sequence, ie., they are cis-acting. However, some transcriptional regulatory elements such as enhancers need not be physically contiguous or located in close proximity to the coding sequences whose transcription they enhance. When there are multiple promoters present, each promoter may independently be the same or different. To facilitate identification of transformants, the recombinant vector desirably comprises a selectable or screenable marker gene. By "marker gene" is meant a gene that imparts a distinct phenotype to cells expressing the marker gene and thus, allows such transformed cells to be distinguished from cells that do not have the marker. A selectable marker gene confers a trait for which one can "select" based on resistance to a selective agent (e.g., a herbicide, antibiotic). A screenable marker gene (or reporter gene) confers a trait that one can identify through observation or testing, that is, by "screening" (e.g., B-glucuronidase, luciferase, GFP or other enzyme activity not present in untransformed cells). Exemplary selectable markers for selection of plant transformants include, but are not limited to, a / yg gene which encodes hygromycin B resistance; a neomycin phosphotransferase (nptll) gene conferring resistance to kanamycin, paromomycin; a glutathione-S-transferase gene from rat liver conferring resistance to glutathione derived herbicides as for example, described in EP 256223; a glutamine synthetase gene conferring, upon overexpression, resistance to glutamine synthetase inhibitors such as phosphinothricin as for example, described in WO 87 / 05327; an acetyltransferase gene from Streptomyces viridochromogenes conferring resistance to the selective agent phosphinothricin as for example, described in EP 275957; a gene encoding a 5-enolshikimate-3-phosphate synthase (EPSPS) conferring tolerance to N-phosphonomethylglycine as for example, described by Hinchee et al. (1988); a bar gene conferring resistance against bialaphos as for example, described in ‘WQ091 / 02071; a nitrilase gene such as bxn from Klebsiella ozaenae which confers resistance to bromoxynil (Stalker et al., 1988); a dihydrofolate reductase (DHFR) gene conferring resistance to methotrexate (Thillet et al., 1988); a mutant acetolactate synthase gene (ALS) which confers resistance to imidazolinone, sulfonylurea, or other ALS-inhibiting chemicals (EP 154,204); a mutated anthranilate synthase gene that confers resistance to 5-methyl tryptophan; or a dalapon dehalogenase gene that confers resistance to the herbicide. Preferably, the recombinant vector is stably incorporated into the genome of the cell such as the plant cell. Accordingly, the recombinant vector may comprise appropriate elements which allow the vector to be incorporated into the genome, or into a chromosome of the cell. Expression Vector As used herein, an "expression vector” is a DNA vector that is capable of transforming a host cell and of effecting expression of an RNA molecule defined herein. Expression vectors of the present invention contain regulatory sequences such as transcription control sequences, translation control sequences, origins of replication, and other regulatory sequences that are compatible with the host cell and that control the expression of RNA molecule according to the present disclosure. In particular, expression vectors of the present invention include transcription control sequences. Transcription control sequences are sequences which control the initiation, elongation, and termination of transcription. Particularly important transcription control sequences are those which control transcription initiation such as promoter, enhancer, operator and repressor sequences. The choice of the regulatory sequences used may depends on the target plant or part therof. Such regulatory sequences may be obtained from any eukaryotic organism such as plants or plant viruses, or may be chemically synthesized. Exemplary vectors suitable for stable transfection of plant cells or for the establishment of transgenic plants have been described in for example, Pouwels et al., Cloning Vectors: A Laboratory Manual, 1985, supp. 1987, Weissbach and Weissbach, Methods for Plant Molecular Biology, Academic Press, 1989, and Gelvin et al., Plant Molecular Biology Manual, Kluwer Academic Publishers, 1990. Typically, plant expression vectors include for example, one or more cloned plant genes under the transcriptional control of 5' and 3' regulatory sequences and a dominant selectable marker. Such plant expression vectors also can contain a promoter regulatory region (e.g., a regulatory region controlling inducible or constitutive, environmentally- or developmentally-regulated, or cell- or tissue-specific expression), a transcription initiation start site, a ribosome binding site, a transcription termination site, and / or a polyadenylation signal. Vectors of the invention can also be used to produce RNA molecules defined herein in a cell-free expression system, such systems are well known in the art. In an example, a polynucleotide encoding an RNA molecule according to the present disclosure is operably linked to a promoter capable of directing expressing of the RNA molecule in a host cell. In an example, the promoter functions in vitro. In an example, the promoter is an RNA polymerase promoter. For example, the promoter can be an RNA polymerase III promoter. In another example, the promoter can be an RNA polymerase II promoter. However, the choice of promoter may depend on the target plant or part therof. Exemplary promoters which may be suitable for constitutive expression in plants include, but are not limited to, the cauliflower mosaic virus (CaMV) 35S promoter, the Figwort mosaic virus (FMV) 35S, the light-inducible promoter from the small subunit (SSU) of the ribulose-1,5-bis-phosphate carboxylase, the rice cytosolic triosephosphate isomerase promoter, the adenine phosphoribosyltransferase promoter of Arabidopsis, the rice actin 1 gene promoter, the mannopine synthase and octopine synthase promoters, the Adh promoter, the sucrose synthase promoter, the R gene complex promoter, and the chlorophyll o / f binding protein gene promoter. These promoters have been used to create DNA vectors that have been expressed in plants, see for example, WO 84 / 02913. All of these promoters have been used to create various types of plant-expressible recombinant DNA vectors. For the purpose of expression in source tissues of the plant such as the leaf, seed, root or stem, it is preferred that the promoters utilized in the present invention have relatively high expression in these specific tissues. For this purpose, one may choose from a number of promoters for genes with tissue- or cell-specific, or -enhanced expression. Examples of such promoters reported in the literature include, the chloroplast glutamine synthetase GS2 promoter from pea, the chloroplast fructose-1,6- biphosphatase promoter from wheat, the nuclear photosynthetic ST-LS1 promoter from potato, the serine / threonine kinase promoter and the glucoamylase (CHS) promoter from Arabidopsis thaliana. Also reported to be active in photosynthetically active tissues are the ribulose-1,5-bisphosphate carboxylase promoter from eastern larch (Larix laricina), the promoter for the Cab gene, Cab6, from pine, the promoter for the Cab-1 gene from wheat, the promoter for the Cab-1 gene from spinach, the promoter for the Cab IR gene from rice, the pyruvate, orthophosphate dikinase (PPDK) promoter from Zea mays, the promoter for the tobacco Lhcbl*2 gene, the Arabidopsis thaliana Suc? sucrose-H*® symporter promoter, and the promoter for the thylakoid membrane protein genes from spinach (PsaD, PsaF, PsaE, PC, ENR, AtpC, AtpD, Cab, RbcS). Other promoters for the chlorophyll o / B-binding proteins may also be utilized in the present invention such as the promoters for LhcB gene and PsbP gene from white mustard (Sinapis alba). A variety of plant gene promoters that are regulated in response to environmental, hormonal, chemical, and / or developmental signals, also can be used for expression of RNA-binding protein genes in plant cells, including promoters regulated by heat, light (e.g., pea RbcS-3A promoter, maize RbcS promoter), hormones such as abscisic acid, wounding (e.g., Wunl), or chemicals such as methyl jasmonate, salicylic acid, steroid hormones, alcohol, Safeners (WO 97 / 06269), or it may also be advantageous to employ organ-specific promoters. As used herein, the term "plant storage organ specific promoter” refers to a promoter that preferentially, when compared to other plant tissues, directs gene transcription in a storage organ of a plant. For the purpose of expression in sink tissues of the plant such as the tuber of the potato plant, the fruit of tomato, or the seed of soybean, canola, cotton, Zea mays, wheat, rice, and barley, it is preferred that the promoters utilized in the present invention have relatively high expression in these specific tissues. The promoter for f-conglycinin or other seed-specific promoters such as the napin, zein, linin and phaseolin promoters, can be used. Root specific promoters may also be used. An example of such a promoter is the promoter for the acid chitinase gene. Expression in root tissue could also be accomplished by utilizing the root specific subdomains of the CaMV 35S promoter that have been identified. In another embodiment, the plant storage organ specific promoter is a fruit specific promoter. Examples include, but are not limited to, the tomato polygalacturonase, E8 and Pds promoters, as well as the apple ACC oxidase promoter (for review, see Potenza et al., 2004). In a preferred embodiment, the promoter preferentially directs expression in the edible parts of the fruit, for example the pith of the fruit, relative to the skin of the fruit or the seeds within the fruit. In an embodiment, the inducible promoter is the Aspergillus nidulans alc system. Examples of inducible expression systems which can be used instead of the Aspergillus nidulans alc system are described in a review by Padidam (2003) and Corrado and Karali (2009). In another embodiment, the inducible promoter is a safener inducible promoter such as, for example, the maize [n2-1 or In2-2 promoter (Hershey and Stoner, 1991), the safener inducible promoter is the maize GST-27 promoter (Jepson et al., 1994), or the soybean GH2 / 4 promoter (Ulmasov et al., 1995). In another embodiment, the inducible promoter is a senescence inducible promoter such as, for example, senescence-inducible promoter SAG (senescence associated gene) 12 and SAG 13 from Arabidopsis (Gan, 1995; Gan and Amasino, 1995) and LSC54 from Brassica napus (Buchanan-Wollaston, 1994). Such promoters show increased expression at about the onset of senescence of plant tissues, in particular the leaves. For expression in vegetative tissue leaf-specific promoters, such as the ribulose biphosphate carboxylase (RBCS) promoters, can be used. For example, the tomato RBCS1, RBCS2 and RBCS3A genes are expressed in leaves and light grown seedlings (Meier et al., 1997). A ribulose bisphosphate carboxylase promoters expressed almost exclusively in mesophyll cells in leaf blades and leaf sheaths at high levels, described by Matsuoka et al. (1994), can be used. Another leaf-specific promoter is the light harvesting chlorophyll a / b binding protein gene promoter (see, Shiina et al., 1997). The Arabidopsis thaliana myb-related gene promoter (Atmyb3) described by Li et al. (1996), is leaf-specific. The Atmyb5 promoter is expressed in developing leaf trichomes, stipules, and epidermal cells on the margins of young rosette and cauline leaves, and in immature seeds. A leaf promoter identified in maize by Busk et al. (1997), can also be used. In some instances, for example when LEC2 or BBM is recombinantly expressed, it may be desirable that the transgene is not expressed at high levels. An example of a promoter which can be used in such circumstances is a truncated napin A promoter which retains the seed-specific expression pattern but with a reduced expression level (Tan et al., 2011). The 5' non-translated leader sequence can be derived from the promoter selected to express the heterologous gene sequence of an RNA molecule of the present disclosure, or may be heterologous with respect to the coding region of the enzyme to be produced, and can be specifically modified if desired so as to increase translation of mRNA. For a review of optimizing expression of transgenes, see Koziel et al. (1996). The 5' non-translated regions can also be obtained from plant viral RNAs (Tobacco mosaic virus, Tobacco etch virus, Maize dwarf mosaic virus, Alfalfa mosaic virus, among others), plant genes (wheat and maize chlorophyll a / b binding protein gene leader), or from a synthetic gene sequence. The present invention is not limited to constructs wherein the non-translated region is derived from the 5' non-translated sequence that accompanies the promoter sequence. The leader sequence could also be derived from an unrelated promoter or coding sequence. Leader sequences useful in context of the present invention comprise the maize Hsp70 leader (US 5,362,865 and US 5,859,347), and the TMV omega element. The termination of transcription is accomplished by a 3' non-translated DNA sequence operably linked in the expression vector to the RNA molecule of interest. The 3' non-translated region of a recombinant DNA molecule contains a polyadenylation signal that functions in plants to cause the addition of adenylate nucleotides to the 3' end of the RNA. The 3' non-translated region can be obtained from various genes that are expressed in plant cells. The nopaline synthase 3' untranslated region, the 3' untranslated region from pea small subunit Rubisco gene, the 3' untranslated region from soybean 7S seed storage protein gene are commonly used in this capacity. The 3' transcribed, non-translated regions containing the polyadenylate signal of Agrobacterium tumor-inducing (Ti) plasmid genes are also suitable. In an example, the expression vector comprises a nucleic acid sequence as shown in SEQ ID NO:150. Transfer Nucleic Acids Transfer nucleic acids can be used to deliver an exogenous polynucleotide to a cell and comprise one, preferably two, border sequences and one or more RNA molecules of interest. The transfer nucleic acid may or may not encode a selectable marker. Preferably, the transfer nucleic acid forms part of a binary vector in a bacterium, where the binary vector further comprises elements which allow replication of the vector in the bacterium, selection, or maintenance of bacterial cells containing the binary vector. Upon transfer to a plant cell, the transfer nucleic acid component of the binary vector is capable of integration into the genome of the plant cell or, for transient expression experiments, merely of expression in the cell. As used herein, the term "extrachromosomal transfer nucleic acid" refers to a nucleic acid molecule that is capable of being transferred from a bacterium such as Agrobacterium sp., to a plant cell such as a plant leaf cell. An extrachromosomal transfer nucleic acid is a genetic element that is well-known as an element capable of being transferred, with the subsequent integration of a nucleotide sequence contained within its borders into the genome of the recipient cell. In this respect, a transfer nucleic acid is flanked, typically, by two "border" sequences, although in some instances a single border at one end can be used and the second end of the transferred nucleic acid is generated randomly in the transfer process. An RNA molecule of interest is typically positioned between the left border-like sequence and the right border-like sequence of a transfer nucleic acid. The RNA molecule contained within the transfer nucleic acid may be operably linked to a variety of different promoter and terminator regulatory elements that facilitate its expression, that is, transcription and / or translation of the RNA molecule. Transfer DNAs (T-DNAs) from Agrobacterium sp. such as Agrobacterium tumefaciens or Agrobacterium rhizogenes, and man made variants / mutants thereof are probably the best characterized examples of transfer nucleic acids. Another example is P-DNA ("plant-DNA") which comprises T-DNA border-like sequences from plants. As used herein, "T-DNA" refers to a T-DNA of an Agrobacterium tumefaciens Ti plasmid or from an Agrobacterium rhizogenes Ri plasmid, or variants thereof which function for transfer of DNA into plant cells. The T-DNA may comprise an entire T- DNA including both right and left border sequences, but need only comprise the minimal sequences required in cis for transfer, that is, the right T-DNA border sequence. The T-DNAs of the invention have inserted into them, anywhere between the right and left border sequences (if present), the RNA molecule of interest. The sequences encoding factors required in trans for transfer of the T-DNA into a plant cell such as vir genes, may be inserted into the T-DNA, or may be present on the same replicon as the T-DNA, or preferably are in trans on a compatible replicon in the Agrobacterium host. Such "binary vector systems" are well known in the art. As used herein, "P-DNA" refers to a transfer nucleic acid isolated from a plant genome, or man made variants / mutants thereof, and comprises at each end, or at only one end, a T-DNA border-like sequence. As used herein, a "border" sequence of a transfer nucleic acid can be isolated from a selected organism such as a plant or bacterium, or be a man made variant / mutant thereof. The border sequence promotes and facilitates the transfer of the RNA molecule to which it is linked and may facilitate its integration in the recipient cell genome. In an embodiment, a border-sequence is between 10-80 bp in length. Border sequences from T-DNA from Agrobacterium sp. are well known in the art and include those described in Lacroix et al. (2008). Whilst traditionally only Agrobacterium sp. have been used to transfer genes to plants cells, there are now a large number of systems which have been identified / developed which act in a similar manner to Agrobacterium sp. Several non- Agrobacterium species have recently been genetically modified to be competent for gene transfer (Chung et al., 2006; Broothaerts et al., 2005). These include Rhizobium sp. NGR234, Sinorhizobium meliloti and Mezorhizobium loti. Direct transfer of eukaryotic expression plasmids from bacteria to eukaryotic hosts was first achieved several decades ago by the fusion of mammalian cells and protoplasts of plasmid-carrying Escherichia coli (Schaffner, 1980). Since then, the number of bacteria capable of delivering genes into mammalian cells has steadily increased (Weiss, 2003), being discovered by four groups independently (Sizemore et al. 1995; Courvalin et al., 1995; Powell et al., 1996; Darji et al., 1997). As used herein, the terms "transfection", "transformation" and variations thereof are generally used interchangeably. "Transfected" or "transformed" cells may have been manipulated to introduce the RNA molecule(s) of interest, or may be progeny cells derived therefrom. In an example, the transfer nucleic acid comprises a nucleic acid sequence as shown in SEQ ID NO:150. Recombinant Cells The invention also provides a recombinant cell, for example, a recombinant plant cell, which is a host cell transformed with one or more RNA molecules or vectors defined herein, or combination thereof. Suitable cells of the invention include any cell that can be transformed with an RNA molecule or recombinant vector according to the present disclosure. Preferably, in an example, the host cell is a plant cell. The recombinant cell may be a cell in culture, a cell in vitro, or in an organism such as for example, a plant, or in an organ such as, for example, a seed or a leaf. Preferably, the cell is in a plant, more preferably in the seed of a plant. Host cells into which the RNA molecules(s) are introduced can be either untransformed cells or cells that are already transformed with at least one nucleic acid. Such nucleic acids may be related to lipid synthesis, or unrelated. Host cells of the present invention either can be endogenously (i.e., naturally) capable of expressing RNA molecule(s) defined herein, in which case the recombinant cell derived therefrom has an enhanced capability of producing the RNA molecule(s), or can be capable of producing said RNA molecule(s) only after being transformed with at least one RNA molecule defined herein. In an example, the cell is a cell which is capable of being used for producing lipid. In an embodiment, a recombinant cell of the invention has an enhanced capacity to produce non-polar lipid such as TAG. In a preferred embodiment, the plant cell is a seed cell, in particular, a cell in a cotyledon or endosperm of a seed. Transgenic Plants The invention also provides a plant comprising one or more exogenous RNA molecules defined herein, a cell of according to the present disclosure, a vector according to the present disclosure, or a combination thereof. The term "plant" when used as a noun refers to whole plants, whilst the term "part thereof" refers to plant organs (e.g., leaves, stems, roots, flowers, fruit), single cells (e.g., pollen), seed, seed parts such as an embryo, endosperm, scutellum or seed coat, plant tissue such as vascular tissue, plant cells and progeny of the same. As used herein, plant parts comprise plant cells. As used herein, the terms “in a plant” and “in the plant” in the context of a modification to the plant means that the modification has occurred in at least one part of the plant, including where the modification has occurred throughout the plant, and does not exclude where the modification occurs in only one or more but not all parts of the plant. For example, a tissue-specific promoter is said to be expressed “in a plant”, even though it might be expressed only in certain parts of the plant. Analogously, “a transcription factor polypeptide that increases the expression of one or more glycolytic and / or fatty acid biosynthetic genes in the plant” means that the increased expression occurs in at least a part of the plant. As used herein, the term "plant" is used in it broadest sense, including any organism in the Kingdom Plantae. It also includes red and brown algae as well as green algae. It includes, but is not limited to, any species of flowering plant, grass, crop or cereal (e.g., oilseed, maize, soybean), fodder or forage, fruit or vegetable plant, herb plant, woody plant or tree. It is not meant to limit a plant to any particular structure. It also refers to a unicellular plant (e.g., microalga). The term "part thereof” in reference to a plant refers to a plant cell and progeny of same, a plurality of plant cells, a structure that is present at any stage of a plant's development, or a plant tissue. Such structures include, but are not limited to, leaves, stems, flowers, fruits, nuts, roots, seed, seed coat, embryos. The term "plant tissue” includes differentiated and undifferentiated tissues of plants including those present in leaves, stems, flowers, fruits, nuts, roots, seed, for example, embryonic tissue, endosperm, dermal tissue (e.g., epidermis, periderm), vascular tissue (e.g. xylem, phloem), or ground tissue (comprising parenchyma, collenchyma, and / or sclerenchyma cells), as well as cells in culture (e.g., single cells, protoplasts, callus, embryos, etc.). Plant tissue may be in planta, in organ culture, tissue culture, or cell culture. As herein herein, a “seedling consists” refers to the stage of plant growth spanning emergence from the seed up until the formation of the first true leaves. In am enbodiment, the seedling comprises of three main parts: the radicle (embryonic root), the hypocotyl (embryonic shoot), and the cotyledon(s). Different amounts of 18:3 and 16:3 fatty acids are found within the glycolipids of different plant species. This is used to distinguish between 18:3 plants whose fatty acids with 3 double bonds are generally always Cis atoms long and the 16:3 plants that contain both Cis- and Cis-fatty acids. In 18:3 chloroplasts, enzymic activities catalyzing the conversion of phosphatidate to diacylglycerol and of diacyiglycerol to monogalactosyl diacylglycerol (MGD) are significantly less active than in 16:3 chloroplasts. In leaves of 18:3 plants, chloroplasts synthesize stearoyl-ACP2 in the stroma, introduce the first double bond into the saturated hydrocarbon chain, and then hydrolyze the thioester. Released oleate is exported across chloroplast envelopes into membranes of the eucaryotic part of the cell, probably the endoplasmic reticulum, where it is incorporated into PC. PC-linked oleoyl groups are desaturated in these membranes and subsequently move back into the chloroplast. The MGD-linked acyl groups are substrates for the introduction of the third double bond to yield MGD with two linolenoyl residues. This galactolipid is characteristic of 18:3 plants such as Asteraceae and Fabaceae, for example. In photosynthetically active cells of 16:3 plants which are represented, for example, by members of Apiaceae and Brassicaceae, two pathways operate in parallel to provide thylakoids with MGD. The cooperative ‘encaryotic' sequence is supplemented to various extents by a 'procaryotic’ pathway. Its reactions are confined to the chloroplast and result in a typical arrangement of acyl groups as well as their complete desaturation once they are esterified to MGD. Procaryotic DAG backbones carry C16:0 and its desaturation products at C-2 from which position C18: fatty acids are excluded. The C-1 position is occupied by C18 fatty acids and to a small extent by C16 groups. The similarity in DAG backbones of lipids from blue-green algae with those synthesized by the chloroplast-confmed pathway in 16:3 plants suggests a phylogenetic relation and justifies the term procaryotic. As used herein, the term "vegetative tissue" or "vegetative plant part” is any plant tissue, organ or part other than organs for sexual reproduction of plants. The organs for sexual reproduction of plants are specifically seed bearing organs, flowers, pollen, fruits and seeds. Vegetative tissues and parts include at least plant leaves, stems (including bolts and tillers but excluding the heads), tubers and roots, but excludes flowers, pollen, seed including the seed coat, embryo and endosperm, fruit including mesocarp tissue, seed-bearing pods and seed-bearing heads. In one embodiment, the vegetative part of the plant is an aerial plant part. In another or further embodiment, the vegetative plant part is a green part such as a leaf or stem. A "transgenic plant" or variations thereof refers to a plant that contains a transgene not found in a wild-type plant of the same species, variety or cultivar. Transgenic plants as defined in the context of the present invention include plants and their progeny which have been genetically modified using recombinant techniques to cause production of at least one polypeptide defined herein in the desired plant or part thereof. Transgenic plant parts has a corresponding meaning. The terms "seed" and "grain" are used interchangeably herein. "Grain" refers to mature grain such as harvested grain or grain which is still on a plant but ready for harvesting, but can also refer to grain after imbibition or germination, according to the context. Mature grain commonly has a moisture content of less than about 18%. In a preferred embodiment, the moisture content of the grain is at a level which is generally regarded as safe for storage, preferably between 5% and 15%, between 6% and 8%, between 8% and 10%, or between 10% and 15%. "Developing seed" as used herein refers to a seed prior to maturity, typically found in the reproductive structures of the plant after fertilisation or anthesis, but can also refer to such seeds prior to maturity which are isolated from a plant. Mature seed commonly has a moisture content of less than about 12%. As used herein, the term "plant storage organ" refers to a part of a plant specialized to store energy in the form of for example, proteins, carbohydrates, lipid. Examples of plant storage organs are seed, fruit, tuberous roots, and tubers. A preferred plant storage organ of the invention is seed. As used herein, the term "phenotypically normal” refers to a genetically modified plant or part thereof, for example a transgenic plant, or a storage organ such as a seed, tuber or fruit of the invention not having a significantly reduced ability to grow and reproduce when compared to an unmodified plant or part thereof. Preferably, the biomass, growth rate, germination rate, storage organ size, seed size and / or the number of viable seeds produced is not less than 90% of that of a plant lacking said recombinant polynucleotide when grown under identical conditions. This term does not encompass features of the plant which may be different to the wild-type plant but which do not affect the usefulness of the plant for commercial purposes such as, for example, a ballerina phenotype of seedling leaves. In an embodiment, the genetically modified plant or part thereof which is phenotypically normal comprises a recombinant polynucleotide encoding a silencing suppressor operably linked to a plant storage organ specific promoter and has an ability to grow or reproduce which is essentially the same as a corresponding plant or part thereof not comprising said polynucleotide. Plants provided by or contemplated for use in the practice of the present invention include both monocotyledons and dicotyledons. In preferred embodiments, the plants of the present invention are crop plants (for example, cereals and pulses, maize, wheat, potatoes, rice, sorghum, millet, cassava, barley) or legumes such as soybean, beans or peas. The plants may be grown for production of edible roots, tubers, leaves, stems, flowers or fruit. The plants may be vegetable plants whose vegetative parts are used as food. The plants of the invention may be: Acrocomia aculeata (macauba palm), Arabidopsis thaliana, Aracinis hypogaea (peanut), Astrocarywm murumury (murumurn), Astrocaryum vulgare (tucuma), Artalea geraensis (Indaié-rateiro), Artalea humilis (American oil palm), Attalea oleifera (andaid), Artalea phalerata (uricuri), Attalea speciosa (babassu), Avena sativa (oats), Bera vulgaris (sugar beet), Brassica sp. such as Brassica carinata, Brassica juncea, Brassica napobrassica, Brassica napus (canola), Camelina sativa (false flax), Cannabis sativa (hemp), Carthamus tinctorius (safflower), Caryocar brasiliense (pequi), Cocos nucifera (Coconut), Crambe abyssinica (Abyssinian kale), Cucumis melo (melon), Elaeis guineensis (African palm), Glycine max (soybean), Gossypium hirsutum (cotton), Helianthus sp. such as Helianthus annuus (sunflower), Hordeum vulgare (barley), Jatropha curcas (physic nut), Joannesia princeps (arara nut-tree), Lemna sp. (duckweed) such as Lemna aequinoctialis, Lemna disperma, Lemna ecuadoriensis, Lemna gibba (swollen duckweed), Lemna japonica, Lemna minor, Lemna minuta, Lemna obscura, Lemna paucicostata, Lemna perpusilla, Lemna tenera, Lemna trisulca, Lemna turionifera, Lemna valdiviana, Lemna yungensis, Licania rigida (oiticica), Linum usitatissimum (flax), Lupinus angustifolius (lupin), Mauritia flexuosa (buriti palm), Maximiliana maripa (inaja palm), Miscanthus sp. such as Miscanthus x giganteus and Miscanthus sinensis, Nicotiana sp. (tabacco) such as Nicotiana tabacum or Nicotiana benthamiana, Oenocarpus bacaba (bacaba-do-azeite), Oenocarpus bataua (pataud), Oenocarpus distichus (bacaba-de-leque), Oryza sp. (rice) such as Oryza sativa and Oryza glaberrima, Panicum virgatum (switchgrass), Paraqueiba paraensis (mari), Persea amencana (avocado), Pongamia pinnata (Indian beech), Populus trichocarpa, Ricinus communis (castor), Saccharum sp. (sugarcane), Sesamum indicum (sesame), Solanum tuberosum (potato), Sorghum sp. such as Sorghum bicolor, Sorghum vulgare, Theobroma grandiforum (cupuassu), Trifolium sp., Trithrinax brasiliensis (Brazilian needle palm), Triticum sp. (wheat) such as Triticum aestivum, Zea mays (corn), alfalfa (Medicago sativa), rye (Secale cerale), sweet potato (Lopmoea batatus), cassava (Manihot esculenta), coffee (Cofea spp.), pineapple (Anana comosus), citris tree (Citrus spp.), cocoa (Theobroma cacao), tea (Camellia senensis), banana (Musa spp.), avocado (Persea americana), fig (Ficus casica), guava (Psidium guajava), mango (Mangifer indica), olive (Olea europaea), papaya (Carica papaya), cashew (Anacardium occidentale), macadamia (Macadamia intergrifolia) and almond (Prunus amygdalus). For example, plants of the disclosure may be Nicotiana benthamiana. In preferred examples, plants of the disclosure are wheat, Brassica sp. or sugarbeet (Beta vulgaris). Other preferred plants include C4 grasses such as, in addition to those mentioned above, Andropogon gerardi, Bouteloua curtipendula, B. gracilis, Buchloe dactyloides, Schizachyrium scoparium, Sorghastrum nutans, Sporobolus cryptandrus; C3 grasses such as Elymus canadensis, the legumes Lespedeza capitata and Petalostemum villosum, the forb Aster azureus; and woody plants such as Quercus ellipsoidalis and Q. macrocarpa. Other preferred plants include C3 grasses. In a preferred embodiment, the plant is an angiosperm. In an embodiment, the plant is an oilseed plant, preferably an oilseed crop plant. As used herein, an "oilseed plant” is a plant species used for the commercial production of lipid from the seeds of the plant. The oilseed plant may be, for example, oil-seed rape (such as canola), maize, sunflower, safflower, soybean, sorghum, flax (linseed) or sugar beet. Furthermore, the oilseed plant may be other Brassicas, cotton, peanut, poppy, rutabaga, mustard, castor bean, sesame, safflower, Jatropha curcas or nut producing plants. The plant may produce high levels of lipid in its fruit such as olive, oil palm or coconut. Horticultural plants to which the present invention may be applied are lettuce, endive, or vegetable Brassicas including cabbage, broccoli, or cauliflower. The present invention may be applied in tobacco, cucurbits, carrot, strawberry, tomato, Or pepper. In a preferred embodiment, the plant is a non-transgenic plant. In a preferred embodiment, the transgenic plant is homozygous for each and every gene that has been introduced (transgene) so that its progeny do not segregate for the desired phenotype. The transgenic plant may also be heterozygous for the introduced transgenes), preferably uniformly heterozygous for the transgene such as for example, in F1 progeny which have been grown from hybrid seed. Such plants may provide advantages such as hybrid vigour, well known in the art. Transformation RNA molecules disclosed herein may be stably introduced to above referenced host cells and / or plants. For the avoidance of doubt, an example of the present disclosure encompasses an above referenced plant stably transformed with an RNA molecule disclosed herein. As used herein, the terms "stably transforming”, "stably transformed" and variations thereof refer to the integration of the RNA molecule or a nucleic acid encoding the same into the genome of the cell such that they are transferred to progeny cells during cell division without the need for positively selecting for their presence. Stable transformants, or progeny thereof, can be identified by any means known in the art such as Southern blots on chromosomal DNA, or in situ hybridization of genomic DNA, enabling their selection. Transgenic plants can be produced using techniques known in the art, such as those generally described in Slater et al, Plant Biotechnology - The Genetic Manipulation of Plants, Oxford University Press (2003), and Christou and Klee, Handbook of Plant Biotechnology, John Wiley and Sons (2004). In an embodiment, plants may be transformed by topically applying an RNA molecule according to the present disclosure to the plant or a part thereof. For example, the RNA molecule may be provided as a formulation with a suitable carrier and sprayed, dusted or otherwise applied to the surface of a plant or part thereof. Accordingly, in an example, the methods of the present disclosure encompass introducing an RNA molecule disclosed herein to a plant, the method comprising topically applying a composition comprising the RNA molecule to the plant or a part thereof. Agrobacterium-mediated transfer is a widely applicable system for introducing genes into plant cells because DNA can be introduced into cells in whole plant tissues, plant organs, or explants in tissue culture, for either transient expression, or for stable integration of the DNA in the plant cell genome. For example, floral-dip (in planta) methods may be used. The use of Agrobacterium-mediated plant integrating vectors to introduce DNA into plant cells is well known in the art. The region of DNA to be transferred is defined by the border sequences, and the intervening DNA (T-DNA) is usually inserted into the plant genome. It is the method of choice because of the facile and defined nature of the gene transfer. Acceleration methods that may be used include for example, microprojectile bombardment and the like. One example of a method for delivering transforming nucleic acid molecules to plant cells is microprojectile bombardment. This method has been reviewed by Yang et al., Particle Bombardment Technology for Gene Transfer, Oxford Press, Oxford, England (1994). Non-biological particles (microprojectiles) that may be coated with nucleic acids and delivered into cells, for example of immature embryos, by a propelling force. Exemplary particles include those comprised of tungsten, gold, platinum, and the like. In another method, plastids can be stably transformed. Methods disclosed for plastid transformation in higher plants include particle gun delivery of DNA containing a selectable marker and targeting of the DNA to the plastid genome through homologous recombination (US 5,451,513, US 5,545,818, US 5,877,402, US 5,932479, and WO 99 / 05265). Other methods of cell transformation can also be used and include but are not limited to the introduction of DNA into plants by direct DNA transfer into pollen, by direct injection of DNA into reproductive organs of a plant, or by direct injection of DNA into the cells of immature embryos followed by the rehydration of desiccated embryos. The regeneration, development, and cultivation of plants from single plant protoplast transformants or from various transformed explants is well known in the art (Weissbach et al, In: Methods for Plant Molecular Biology, Academic Press, San Diego, Calif., (1988)). This regeneration and growth process typically includes the steps of selection of transformed cells, culturing those individualized cells through the usual stages of embryonic development through the rooted plantlet stage. Transgenic embryos and seeds are similarly regenerated. The resulting transgenic rooted shoots are thereafter planted in an appropriate plant growth medium such as soil. The development or regeneration of plants containing the foreign, exogenous gene is well known in the art. Preferably, the regenerated plants are self-pollinated to provide homozygous transgenic plants. Otherwise, pollen obtained from the regenerated plants is crossed to seed-grown plants of agronomically important lines. Conversely, pollen from plants of these important lines is used to pollinate regenerated plants. A transgenic plant of the present invention containing a desired polynucleotide is cultivated using methods well known to one skilled in the art. To confirm the presence of the transgenes in transgenic cells and plants, a polymerase chain reaction (PCR) amplification or Sou...

Claims

CLAIMS 1. An RNA molecule comprising a first RNA component, a second RNA component which is covalently linked to the first RNA component and, optionally, one or more or all of (i) a linking ribonucleotide sequence which covalently links the first and second RNA components, (ii) a 5° leader sequence and (iii) a 3” trailer sequence, wherein the first RNA component consists of, in 5’ to 3’ order, a first 5’ ribonucleotide, a first RNA sequence and a first 3’ ribonucleotide, wherein the first 5° and 3’ ribonucleotides basepair with each other in the first RNA component, wherein the first RNA sequence comprises a first sense ribonucleotide sequence of at least 20 contiguous ribonucleotides, a first loop sequence of at least 4 ribonucleotides and a first antisense ribonucleotide sequence of at least 20 contiguous ribonucleotides, wherein the first antisense ribonucleotide sequence hybridises with the first sense ribonucleotide sequence in the RNA molecule, wherein the first antisense ribonucleotide sequence is capable of hybridising to a first region of a target RNA molecule which modulates the timing of plant flowering, wherein the second RNA component is covalently linked, via the linking ribonucleotide sequence if present or directly if the linking ribonucleotide sequence is not present, to the first 5° ribonucleotide or the first 3’ ribonucleotide, wherein the second RNA component consists of, in 5° to 3’ order, a second 5’ ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, wherein the second 5” and 3’ ribonucleotides basepair to each other in the RNA molecule, wherein the second RNA sequence comprises a second sense ribonucleotide sequence, a second loop sequence of at least 4 ribonucleotides and a second antisense ribonucleotide sequence, wherein the second sense ribonucleotide sequence hybridises with the second antisense ribonucleotide sequence in the RNA molecule, wherein the 5° leader sequence, if present, consists of a sequence of ribonucleotides which is covalently linked to the first 5’ ribonucleotide if the second RNA component is linked to the first 3’ ribonucleotide or to the second 5° ribonucleotide if the second RNA component is linked to the first 5° ribonucleotide, and wherein the 3’ trailer sequence, if present, consists of a sequence of ribonucleotides which is covalently linked to the second 3’ ribonucleotide if the second RNA component is linked to the first 3’ ribonucleotide or to the first 3’ ribonucleotide if the second RNA component is linked to the first 5° ribonucleotide.

2. An RNA molecule comprising a first RNA component, a second RNA component which is covalently linked to the first RNA component and, optionally, one or more or all of (i) a linking ribonucleotide sequence which covalently links the first and second RNA components, (ii) a 5° leader sequence and (iii) a 3” trailer sequence, wherein the first RNA component consists of, in 5’ to 3’ order, a first 5’ ribonucleotide, a first RNA sequence and a first 3’ ribonucleotide, wherein the first 5° and 3’ ribonucleotides basepair, wherein the first RNA sequence comprises a first sense ribonucleotide sequence, a first loop sequence of at least 4 ribonucleotides and a first antisense ribonucleotide sequence, wherein the first sense ribonucleotide sequence and first antisense ribonucleotide sequence each of at least 20 contiguous ribonucleotides whereby the at least 20 contiguous ribonucleotides of the first sense ribonucleotide sequence fully basepair with the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence, wherein the at least 20 contiguous ribonucleotides of the first sense ribonucleotide sequence are identical in sequence to a first region of a target RNA molecule which modulates the timing of plant flowering, wherein the second RNA component is covalently linked, via the linking ribonucleotide sequence if present, to the first 5° ribonucleotide or the first 3’ ribonucleotide, wherein the second RNA component consists of, in 5° to 3’ order, a second 5’ ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, wherein the second 5’ and 3’ ribonucleotides basepair, wherein the second RNA sequence comprises a second sense ribonucleotide sequence, a second loop sequence of at least 4 ribonucleotides and a second antisense ribonucleotide sequence, wherein the second sense ribonucleotide sequence basepairs with the second antisense ribonucleotide sequence, wherein the 5° leader sequence, if present, consists of a sequence of ribonucleotides which is covalently linked to the first 5’ ribonucleotide if the second RNA component is linked to the first 3’ ribonucleotide or to the second 5° ribonucleotide if the second RNA component is linked to the first 5° ribonucleotide, and wherein the 3’ trailer sequence, if present, consists of a sequence of ribonucleotides which is covalently linked to the second 3’ ribonucleotide if the second RNA component is linked to the first 3’ ribonucleotide or to the first 3° ribonucleotide if the second RNA component is linked to the first 5° ribonucleotide.

3. The RNA molecule of claim 1 or claim 2, wherein the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence are all capable of basepairing to nucleotides of the first region of the target RNA molecule.

4. The RNA molecule according to any one of claims 1 to 3, wherein the first sense ribonucleotide sequence is linked covalently to the first 5° ribonucleotide without any intervening nucleotides, or the first antisense ribonucleotide sequence is linked covalently to the first 3’ ribonucleotide without any intervening nucleotides, or both. 5 The RNA molecule according to any one of claims 1 to 4 which comprises the linking ribonucleotide sequence, wherein the linking ribonucleotide sequence is less than 20 ribonucleotides.

6. The RNA molecule of claim 5, wherein the linking ribonucleotide sequence hybridizes to the target RNA molecule.

7. The RNA molecule of claim 5 or claim 6, wherein the linking ribonucleotide sequence is identical to a portion of the complement of the target RNA molecule.

8. The RNA molecule according to any one of claims 5 to 7, wherein the linking ribonucleotide sequence is between 1 and 50 ribonucleotides in length.

9. The RNA molecule according to any one of claims 5 to 7, wherein the linking ribonucleotide sequence is between 1 and 10 ribonucleotides in length.

10. The RNA molecule according to any one of claims 1 to 9 which comprises two or more sense ribonucleotide sequences, and antisense ribonucleotide sequences fully based paired thereto, which are identical in sequence to a region of a target RNA molecule.

11. The RNA molecule of claim 10, wherein the two or more sense ribonucleotide sequences are identical in sequence to different regions of the same target RNA molecule.

12. The RNA molecule of claim 10, wherein the two or more sense ribonucleotide sequences are identical in sequence to a region of different target RNA molecules.

13. The RNA molecule according to any one of claims 1 to 12 which comprises two or more antisense ribonucleotide sequences, and sense ribonucleotide sequences fully based paired thereto, which are each complementary to a region of a target RNA molecule.

14. The RNA molecule of claim 13, wherein the two or more antisense ribonucleotide sequences are complementary to different regions of the same target RNA molecule.

15. The RNA molecule of claim 13 or claim 14, wherein the second of the two or more antisense ribonucleotide sequences are complementary to region of a different target RNA molecule than the first of the two or more antisense ribonucleotide sequences.

16. The RNA molecule according to any one of claims 1 to 15, wherein the two or more sense ribonucleotide sequences have no intervening loop sequences.

17. The RNA molecule according to any one of claims 2 to 16 which is a single strand of ribonucleotides having a 5’ end, at least one sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully base paired with each sense ribonucleotide sequence over at least 21 contiguous nucleotides, at least two loop sequences and a 3’ end.

18. The RNA molecule according to any one of claims 1, or 3 to 16 which is a single strand of ribonucleotides having a 5° end, at least one sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully base paired with each sense ribonucleotide sequence over at least 21 contiguous nucleotides, at least two loop sequences and a 3’ end.

19. The RNA molecule according to any one of claims 1 to 18 which is a single strand of ribonucleotides comprising a 5’ end, the first RNA component comprising a first sense ribonucleotide sequence which is at least 21 nucleotides in length, at least one loop sequence, a first antisense ribonucleotide sequence which hybridises with the first sense ribonucleotide sequence over a length of at least 21 contiguous nucleotides, and the second RNA component comprising a second sense ribonucleotide sequence which is at least 21 nucleotides in length, a loop sequence, a second antisense ribonucleotide sequence which hybridises with the second sense ribonucleotide sequence over a length of at least 21 contiguous nucleotides, and a 3’ end, wherein the RNA molecule has only one 5° end and only one 3’ end.

20. The RNA molecule of claim 19, wherein the ribonucleotide at the 5° end and the ribonucleotide at the 3’ end are adjacent, each base paired and are not directly covalently bonded.

21. The RNA molecule according to any one of claims 1 to 20 which comprises a first antisense ribonucleotide sequence which hybridizes to a first region of a target RNA, a second antisense ribonucleotide sequence which hybridizes to a second region of a target RNA, the second region of the target RNA being different to the first region of the target RNA, and the RNA molecule comprising only one sense ribonucleotide sequence which hybridizes to the target RNA, wherein the two antisense sequences are not contiguous in the RNA molecule.

22. The RNA molecule according to any one of claims 1 to 20 which comprises a first sense ribonucleotide sequence which is at least 60% identical to a first region of a target RNA, a second sense ribonucleotide sequence which is at least 60% identical to a second region of a target RNA, the second region of the target RNA being different to the first region of the target RNA, and the RNA molecule comprising only one antisense ribonucleotide sequence which hybridizes to the target RNA, wherein the two sense sequences are not contiguous in the RNA molecule.

23. The RNA molecule according to any one of claims 1 to 22 which has the 5’ leader sequence.

24. The RNA molecule according to any one of claims 1 to 23 which has the 3’ trailer sequence.

25. The RNA molecule according to any one of claims 1 to 24, wherein each ribonucleotide is covalently linked to two other nucleotides.

26. The RNA molecule of claim 25, wherein at least one or all of the loop sequences are longer than 20 nucleotides.

27. The RNA molecule according to any one of claims 1 to 15, wherein the RNA molecules has none, or one, or two or more bulges, or a double-stranded region of the RNA molecule comprises one, or two, or more nucleotides which are not basepaired in the double-stranded region.

28. The RNA molecule according to any one of claims 1 to 27 which has three, four or more loops.

29. The RNA molecule according to any one of claims 1 to 27 which only has two loops.

30. The RNA molecule according to any one of claims 1 to 29, wherein the target RNA is in a plant cell.

31. The RNA molecule of claim 30, wherein the plant cell is from Arabidopsis, corn, canola, cotton, soybean, alfalfa, lettuce, wheat, barley, rice, legume, Medicago truncatula, sugarbeet or rye.

32. The RNA molecule of claim 30 or claim 31, which is present in a plant cell.

33. The RNA molecule of claim 32 which is expressed in the cell.

34. The RNA molecule according to any one of claims 1 to 33, wherein at least one of the loops is between 4 and 1,000 ribonucleotides, or between 4 and 200 ribonucleotides, in length.

35. The RNA molecule of claim 34, wherein all of the loops are between 4 and 1,000 ribonucleotides, or between 4 and 200 ribonucleotides, in length.

36. The RNA molecule of claim 35, wherein all of the loops are between 4 and 50 ribonucleotides in length.

37. The RNA molecule according to any one of claims 1 to 36, wherein each loop is between 20 and 30 ribonucleotides in length.

38. The RNA molecule according to any one of claims 1 to 37, wherein the target RNA encodes a protein.

39. The RNA molecule according to any one of claims 1 to 38 which comprises an nucleotide sequence set forth in SEQ ID NO: 146 or SEQ ID NO:

147.

40. A chimeric ribonucleic acid (RNA) molecule, comprising a double-stranded RNA (dsRNA) region which comprises a first sense ribonucleotide sequence of at least 20 contiguous nucleotides in length and a first antisense ribonucleotide sequence of at least 20 contiguous nucleotides in length, whereby the first sense ribonucleotide sequence and the first antisense ribonucleotide sequences are capable of hybridising to each other to form the dsRNA region, wherein i) the first sense ribonucleotide sequence consists of, covalently linked in 5° to 3’ order, a first 5° ribonucleotide, a first RNA sequence and a first 3° ribonucleotide, ii) the first antisense ribonucleotide sequence consists of, covalently linked in 5” to 3’ order, a second 5’ ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, iii) the first 5° ribonucleotide basepairs with the second 3’ ribonucleotide to form a terminal basepair of the dsRNA region, iv) the second 5’ ribonucleotide basepairs with the first 3’ ribonucleotide to form a terminal basepair of the dsRNA region, v) between about 5% and about 40% of the ribonucleotides of the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence, in total, are either basepaired in a non-canonical basepair or are not basepaired, vi) the dsRNA region does not comprise 20 contiguous canonical basepairs, vii) the RNA molecule is capable of being processed in a plant cell or in vitro whereby the first antisense ribonucleotide sequence is cleaved to produce short antisense RNA (asRNA) molecules of 20-24 ribonucleotides in length, viii) the RNA molecule or at least some of the asRNA molecules, or both, are capable of reducing the expression or activity of a target RNA molecule which modulates the timing of plant flowering, and ix) the RNA molecule is capable of being made enzymatically by transcription in vitro or in a cell, or both.

41. The chimeric RNA molecule of claim 40, wherein the first sense ribonucleotide sequence is covalently linked to the first antisense ribonucleotide sequence by a first linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides, or between 4 and 1,000 ribonucleotides, or between 4 and 200 ribonucleotides, or between 4 and 50 ribonucleotides, or at least 10 nucleotides, or between 10 and 1,000 ribonucleotides, or between 10 and 200 ribonucleotides, or between 10 and 50 ribonucleotides, in length, whereby the first linking ribonucleotide sequence is covalently linked to either the second 3’ ribonucleotide and the first 5° ribonucleotide or, preferably, to the first 3’ ribonucleotide and the second 5’ ribonucleotide, so that the sequences are comprised in a single, contiguous strand of RNA.

42. The chimeric RNA molecule of claim 41, wherein the loop sequence in the RNA molecule comprises one or more binding sequences which are complementary to an RNA molecule which is endogenous to the plant cell, and / or the loop sequence in the RNA molecule comprises an open reading frame which encodes a polypeptide or a functional polynucleotide.

43. The chimeric RNA molecule according to any one of claims 40 to 42, wherein between about 5% and about 40% of the ribonucleotides of the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence of the dsRNA, in total, are basepaired in non-canonical basepairs, preferably G:U basepairs.

44. The chimeric RNA molecule according to any one of claims 40 to 43, the first antisense ribonucleotide sequence is fully complementary to a region of the target RNA and the first sense ribonucleotide sequence is different in sequence to the region of the target RNA by the substitution of C nucleotides in the region of the target RNA with U nucleotides.

45. The chimeric RNA molecule according to any one of claims 40 to 44 which comprises a second sense ribonucleotide sequence and the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence are linked by a first linking ribonucleotide sequence comprising a loop sequence of at least 4 nucleotides in length, whereby the first linking ribonucleotide sequence is covalently linked to the first 3’ ribonucleotide and the second 5° ribonucleotide, and the RNA molecule further comprises a second linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides in length and which is covalently linked to the second 3’ ribonucleotide and the second sense ribonucleotide sequence.

46. The chimeric RNA molecule according to any one of claims 40 to 45 which comprises a second antisense ribonucleotide sequence and the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence are linked by a first linking ribonucleotide sequence comprising a loop sequence of at least 4 nucleotides in length, whereby the first linking ribonucleotide sequence is covalently linked to the second 3’ ribonucleotide and the first 5’ ribonucleotide, and the RNA molecule further comprises a second linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides in length and which is covalently linked to the second 3’ ribonucleotide and the second antisense ribonucleotide sequence.

47. The chimeric RNA molecule according to any one of claims 40 to 45 which comprises a second sense ribonucleotide sequence and a second antisense ribonucleotide sequence, wherein the second sense ribonucleotide sequence and the second antisense ribonucleotide sequences are capable of hybridising to each other to form a second dsRNA region, and the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence are linked by a first linking ribonucleotide sequence comprising a loop sequence of at least 4 nucleotides in length, whereby the first linking ribonucleotide sequence is covalently linked to the first 3’ ribonucleotide and the second 5” ribonucleotide, and the RNA molecule optionaly comprises a second linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides in length and which is covalently linked to the second 3” ribonucleotide and the second sense ribonucleotide sequence or which covalently links the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence.

48. The chimeric RNA molecule according to any one of claims 40 to 45 which comprises a second sense ribonucleotide sequence and a second antisense ribonucleotide sequence and the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence are linked by a first linking ribonucleotide sequence comprising a loop sequence of at least 4 nucleotides in length, whereby the first linking ribonucleotide sequence is covalently linked to the second 3’ ribonucleotide and the first 5° ribonucleotide, and the RNA molecule further comprises a second linking ribonucleotide sequence which comprises a loop sequence of at least 4 nucleotides in length and which is covalently linked to the first 3’ ribonucleotide and the second antisense ribonucleotide sequence, or which covalently links the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence.

49. The chimeric RNA molecule according to any one of claims 45 to 48, wherein the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence each comprise at least 20 contiguous nucleotides in length.

50. The chimeric RNA molecule according to any one of claims 45 to 49, wherein the first and second sense ribonucleotide sequences are covalently linked by an intervening ribonucleotide sequence which is unrelated in sequence to the target RNA molecule, or which is related in sequence to the target RNA molecule, or the first and second sense ribonucleotide sequences are covalently linked without an intervening ribonucleotide sequence.

51. The chimeric RNA molecule according to any one of claims 45 to 50, wherein the first and second antisense ribonucleotide sequences are covalently linked by an intervening ribonucleotide sequence which is unrelated in sequence to the complement of a target RNA molecule, or which is related in sequence to the complement of a target RNA molecule, or the first and second antisense ribonucleotide sequences are covalently linked without an intervening ribonucleotide sequence.

52. The chimeric RNA molecule according to any one of claims 45 to 51, wherein between 5% and 40% of the ribonucleotides of the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence, in total, are either basepaired in a non-canonical basepair or are not basepaired, preferably basepaired in G:U basepairs, wherein the second dsRNA region does not comprise 20 contiguous canonical basepairs, and wherein the RNA molecule is capable of being processed in a eukaryotic cell or in vitro whereby the second antisense ribonucleotide sequence is cleaved to produce short antisense RNA (asRNA) molecules of 20-24 ribonucleotides in length.

53. The chimeric RNA molecule according to any one of claims 45 to 52, wherein each linking ribonucleotide sequence is independently between 4 and about 2000 nucleotides in length, preferably between 4 and about 1200 nucleotides in length, more preferably between 4 and about 200 nucleotides in length and most preferably between 4 and about 50 nucleotides in length.

54. The chimeric RNA molecule according to any one of claims 40 to 53 which further comprises a 5° leader sequence or a 3’ trailer sequence, or both.

55. A chimeric RNA molecule comprising a first RNA component and a second RNA component which is covalently linked to the first RNA component, wherein the first RNA component comprises a first double-stranded RNA (dsRNA) region, which comprises a first sense ribonucleotide sequence and a first antisense ribonucleotide sequence which are capable of hybridising to each other to form the first dsRNA region, and a first intervening ribonucleotide sequence of at least 4 nucleotides which covalently links the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence, wherein the second RNA component comprises a second sense ribonucleotide sequence, a second antisense ribonucleotide sequence and a second intervening ribonucleotide sequence of at least 4 ribonucleotides which covalently links the second sense ribonucleotide sequence and the second antisense ribonucleotide sequence, wherein the second sense ribonucleotide sequence hybridises with the second antisense ribonucleotide sequence in the RNA molecule, wherein in the first RNA component, i) the first sense ribonucleotide sequence consists of at least 20 contiguous ribonucleotides covalently linked, in 5° to 3” order, a first 5° ribonucleotide, a first RNA sequence and a first 3’ ribonucleotide, ii) the first antisense ribonucleotide sequence consists of at least 20 contiguous ribonucleotides covalently linked, in 5° to 3’ order, a second 5’ ribonucleotide, a second RNA sequence and a second 3’ ribonucleotide, iii) the first 5° ribonucleotide basepairs with the second 3’ ribonucleotide, iv) the second 5’ ribonucleotide basepairs with the first 3’ ribonucleotide, v) between 5% and 40% of the ribonucleotides of the first sense ribonucleotide sequence and the first antisense ribonucleotide sequence, in total, are either basepaired in a non-canonical basepair or are not basepaired, and vi) the first dsRNA region does not comprise 20 contiguous canonical basepairs, wherein the chimeric RNA molecule is capable of being processed in a plant cell or in vitro whereby the first antisense ribonucleotide sequence is cleaved to produce short antisense RNA (asRNA) molecules of 20-24 ribonucleotides in length, and wherein (d) the chimeric RNA molecule or at least some of the asRNA molecules, or both, are capable of reducing the expression or activity of a target RNA molecule which modulates plant flowering, or (e) the first antisense ribonucleotide sequence comprises a sequence of at least 20 contiguous ribonucleotides which is at least 50% identical in sequence, preferably at least 90% or 100% identical in sequence, to a region of the complement of the target RNA molecule, or (f) both (a) and (b).

56. The chimeric RNA molecule according to any one of claims 40 to 55, wherein the at least 20 contiguous ribonucleotides of the first antisense ribonucleotide sequence are all capable of basepairing to nucleotides of a first region of the target RNA molecule.

57. The chimeric RNA molecule according to any one of claims 40 to 56, wherein the RNA molecule comprises two or more antisense ribonucleotide sequences, and sense ribonucleotide sequences based paired thereto, which antisense sequences are each complementary, preferably fully complementary, to a region of a target RNA molecule.

58. The chimeric RNA molecule of claim 57, wherein the two or more antisense ribonucleotide sequences are complementary to different regions of the same target RNA molecule.

59. The chimeric RNA molecule of claim 57, wherein the two or more antisense ribonucleotide sequences are complementary to regions of different target RNA molecules.

60. The chimeric RNA molecule according to any one of claims 40 to 59 which comprises a hairpin RNA (hpRNA) structure having a 5° end, a sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully base paired with the sense ribonucleotide sequence over at least 21 contiguous nucleotides, an intervening loop sequence and a 3’ end.

61. The chimeric RNA molecule according to any one of claims 40 to 59 which comprises a single strand of ribonucleotides having a 5’ end, at least one sense ribonucleotide sequence which is at least 21 nucleotides in length, an antisense ribonucleotide sequence which is fully base paired with each sense ribonucleotide sequence over at least 21 contiguous nucleotides, at least two loop sequences and a 3” end.

62. The chimeric RNA molecule according to any one of claims 40 to 61, wherein between about 15% and about 30%, or between about 16% and about 25%, of the ribonucleotides of the sense ribonucleotide sequence and the antisense ribonucleotide sequence, in total, are either basepaired in a non-canonical basepair or are not basepaired, preferably basepaired in non-canonical basepairs, more preferably basepaired in G:U basepairs.

63. The chimeric RNA molecule according to any one of claims 40 to 62, wherein at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 97%, or 100% of the non-canonical basepairs are G:U basepairs.

64. The chimeric RNA molecule according to any one of claims 40 to 63, wherein less than 25%; less than 20%, less than 15%, less than 10%, less than 5%, less than 1% or none, of the ribonucleotides in the dsRNA region are not basepaired.

65. The chimeric RNA molecule according to any one of claims 40 to 64, wherein every one in four to every one in six ribonucleotides in the dsRNA region form a non- canonical basepair or are not basepaired, preferably form a G:U basepair.

66. The chimeric RNA molecule according to any one of claims 40 to 65, wherein the dsRNA region does not comprise 8 contiguous canonical basepairs.

67. The chimeric RNA molecule according to any one of claims 40 to 66, wherein the dsRNA region comprises at least 8 contiguous canonical basepairs, preferably at least 8 but not more than 12 contiguous canonical basepairs.

68. The chimeric RNA molecule according to any one of claims 40 to 67, wherein all of the ribonucleotides in the dsRNA region, or in each dsRNA region, are base- paired with a canonical basepair or a non-canonical basepair.

69. The chimeric RNA molecule according to any one of claims 40 to 67, wherein one or more ribonucleotides of the sense ribonucleotide sequence or one or more ribonucleotides of the antisense ribonucleotide sequence, or both, are not basepaired.

70. The chimeric RNA molecule according to any one of claims 40 to 69, wherein the antisense RNA sequence is less than 100% identical, or between about 80% and 99.9% identical, or between about 90% and 98% identical, or between about 95% and 98% identical, in sequence to the complement of a region of the target RNA molecule.

71. The chimeric RNA molecule according to any one of claims 40 to 69, wherein the antisense RNA sequence is 100% identical in sequence to a region of the target RNA molecule.

72. The chimeric RNA molecule according to any one of claims 40 to 71, wherein the sense and / or antisense ribonucleotide sequence, preferably both, is at least 50, at least about 100, at least about 200, at least about 300, at least about 400, at least about 500, at least about 600, at least about 700, at least about 800, at least about 900, at least about 1,000, or about 100 to about 1,000, or 20 to about 1000 nucleotides, or 20 to about 500 nucleotides, in length.

73. The chimeric RNA molecule according to any one of claims 40 to 72, wherein the number of ribonucleotides in the sense ribonucleotide sequence is between about 90% and about 110% of the number of ribonucleotides in the antisense ribonucleotide sequence.

74. The chimeric RNA molecule according to any one of claims 40 to 73, wherein the number of ribonucleotides in the sense ribonucleotide sequence is the same as the number of ribonucleotides in the antisense ribonucleotide sequence.

75. The chimeric RNA molecule according to any one of claims 40 to 74, wherein the chimeric RNA molecule further comprises a 5’ extension sequence which is covalently linked to the first 5° ribonucleotide or a 3’ extension sequence which is covalently linked to the second 3’ ribonucleotide, or both.

76. The chimeric RNA molecule according to any one of claims 40 to 75, wherein the chimeric RNA molecule further comprises a 5’ extension sequence which is covalently linked to the second 5° ribonucleotide or a 3’ extension sequence which is covalently linked to the first 3’ ribonucleotide, or both.

77. The chimeric RNA molecule according to any one of claims 40 to 76, which comprises two or more dsRNA regions which are the same or different.

78. The chimeric RNA molecule according to any one of claims 40 to 77, wherein when expressed in a plant cell more asRNA molecules are formed that are 22 and / or 20 ribonucleotides in length when compared to processing of an analogous RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs.

79. The RNA molecule according to any one of claims 1 to 39, or the chimeric RNA molecule according to any one of claims 40 to 78, wherein the target RNA i) encodes VERNALIZATION! (VRNI1), VERNALIZATION2 (VRN2), EARLYINSHORTDAYS4, FLOWERING LOCUS T1 (FT1), FLOWERING LOCUS T2 (FT2), Flowering Locus C (FLC), FRIGIDA (FRI) or CONSTANS in the plant species of interest, and / or ii) comprises a region of a nucleotide sequence set forth in any one or more of SEQ ID NO’s 146, 147, or 151 to 228 (where the T's are replaced with U’s), or a complement (antisense) of the region of the sequence, or both the region and the complement, or a nucleotide sequence 95%, preferably, 99%, identical thereto (where the T’s are replaced with U’s).

80. The RNA molecule according to any one of claims 1 to 39, or the chimeric RNA molecule according to any one of claims 40 to 78, wherein the target RNA is a gene transcript of the following from wheat, VRN1 / VRN-A1 (SEQ ID NO:151); VRN2 (SEQ ID NO:145); FT (SEQ ID NO:152) or homologous genes in other species, preferably cereal species.

81. The RNA molecule according to any one of claims 1 to 39, or the chimeric RNA molecule according to any one of claims 40 to 78, wherein the target RNA is a gene transcript of the following from canola, BnFLC1 (SEQ ID NO:179); BnFLC2 (SEQ ID NO:180); BnFLC3 (SEQ ID NO:181); BnFLC4 (SEQ ID NO:182); BnFLC5 (SEQ ID NO:183); BnFRI (SEQ ID NO:184); BnFT (SEQ ID NO:185) or homologous genes in other species, preferably a Brassica sp.

82. The RNA molecule according to any one of claims 1 to 39, or the chimeric RNA molecule according to any one of claims 40 to 78, wherein the target RNA is a gene transcript of the following from Arabidopsis, FRI; FLC; VRNI; VRN2; VIN3; FT; SOC1; CO (constans); LFY; AP1, or homologous genes in other species.

83. The RNA molecule according to any one of claims 1 to 39, or the chimeric RNA molecule according to any one of claims 40 to 78, wherein the target RNA is a gene transcript of the following from rice, OsPhyB (SEQ ID NO:156); OsCol4 (SEQ ID NO:157); RFT1 (SEQ ID NO:158); OsSNB (SEQ ID NO:159); OsIDS1 (SEQ ID NO:160); OsGI (SEQ ID NO:161), OsMADSS50 (SEQ ID NO:162), OsMADSS5 (SEQ ID NO:163) or OsLFY (SEQ ID NO:164), or homologous genes in other species.

84. The RNA molecule according to any one of claims 1 to 39, or the chimeric RNA molecule according to any one of claims 40 to 78, wherein i) the target RNA is a gene transcript of the following from Medicago truncatula, MtFTal (SEQ ID NO:186); MtFTbl (SEQ ID NO:187), MtYFL (SEQ ID NO:210), MtSOCla, MtSOC1b, MtSOC1c, or homologous genes in other species, ii) the target RNA is a gene transcript of the one of the following from maize (Zea mays): ZmMADS1 / ZmMS5 (SEQ ID NO:165), PHYAL (SEQ ID NO:166), PHYA? (SEQ ID NO:167), PHYB1 (SEQ ID NO:168), PHYB2 (SEQ ID NO:169), PHYC1 (SEQ ID NO:170), PHYC2 (SEQ ID NO:171), ZmLD (SEQ ID NO:172), ZmFL1 (SEQ ID NO:173), ZmFL2 (SEQ ID NO:174), DWARFS (SEQ ID NO:175), ZmAN1 (SEQ ID NO:176), ZmID1 (SEQ ID NO:177), ZCN8 (SEQ ID NO:178), or homologous genes in other species, preferably cereal species, iii) the target RNA is a gene transcript of one of the following from alfalfa (Medicago sativa), MsFRI-L (SEQ ID NO:188), MsSOCla (SEQ ID NO:189), or MSFT (SEQ ID NO:190), or homologous genes in other species, iv) the target RNA is a gene transcript of one of the following from soybean (Glycine max): encoded by the gene GLYMA_05G148700 with any one or more of the following transcript variants GmFLC-X1 (SEQ ID NO:191), GmFLC-X2 (SEQ ID NO:192), GmFLC-X3 (SEQ ID NO:193), GmFLC-X4 (SEQ ID NO:194), GmFLC-X5 (SEQ ID NO:195), GmFLC-X6 (SEQ ID NO:196), GmFLC-X7 (SEQ ID NO:197), GmFLC-X8 (SEQ ID NO:198), GmFLC-X9 (SEQ ID NO:199), SUPPRESSOR OF FRI (SEQ ID NO:200), GmFRI (SEQ ID NO:201), GmFT2A (SEQ ID NO:202), GmPHYA3 (SEQ ID NO:203), or GIGANTEA (SEQ ID NO:204), or homologous genes in other species, v) the target RNA is a gene transcript of the following from sugarbeet (Beta vulgaris), BvBTC1 (SEQ ID NO:205), preferably BvFT1 (SEQ ID NO:206) and / or BvFT2 (SEQ ID NO:207), or homologous genes in other species, vi) the target RNA is a gene transcript of one of the following genes from Brassica rapa, which may be turnip, cabbage, bok choi, turnip rape or related crucifers: BrFLC2 (SEQ ID NO:208), BrFT or BrFRI (SEQ ID NO:209), or homologous genes in other species, vii) the target RNA is a gene transcript of one of the following from cotton (Gossypium hirsutum): GhCO, GhFLC, GhFRI, GhFT, GhLFY, GhPHYA, GhPHYB, GhSOC1, GhVRN1, GhVRN2, GhVRNS, or homologous genes in other species, viii) the target RNA is a gene transcript of one of the following from onion (Allium cepa): AcGI (SEQ ID NO:211), AcFKF (SEQ ID NO:212), AcZTL (SEQ ID NO:213), AcCOL (SEQ ID NO:214), AcFTL (SEQ ID NO:215), AcFT1 (SEQ ID NO:216), AcFT2 (SEQ ID NO:217), AcFT6 (SEQ ID NO:218), AcPHYA (SEQ ID NO:219), AcCOP1 (SEQ ID NO:220), or homologous genes in other species, ix) the target RNA is a gene transcript of one of the following from asparagus (Asparagus officinalis): FPA, TWIN SISTER of FT-like, MOTHER of FT, PHOTOPERIOD-INDEPENDENT EARLY FLOWERING 1, FLOWERING LOCUS T-like, Flowering locus K, Flowering time control protein FY, flowering time control protein FCA-like, or homologous genes in other species, x) the target RNA is a gene transcript of one of the following from lettuce (Lactuca sativa): LsFT (SEQ ID NO:221), TFL1-like (SEQ ID NO:222), TFL1 homolog 1-like (SEQ ID NO:223), LsFLC (SEQ ID NO:224), LsSOC]1-like (SEQ ID NO:225, SEQ ID NO:226 or SEQ ID NO:227), TsLFY (SEQ ID NO:228), or homologous genes in other species, or xi) the target RNA is a gene transcript of the one of the following from barley: HvVRNI1 (SEQ ID NO:153), HvVRN2 (SEQ ID NO:154) or HVFT (SEQ ID NO:155), or homologous genes in other species, preferably cereal species.

85. The RNA molecule according to any one of claims 1 to 39, or the chimeric RNA molecule according to any one of claims 40 to 78, wherein the target RNA is a miRNA.

86. The RNA molecule or the chimeric RNA molecule according to claim 86, wherein the miRNA is miR-156 or miR-172.

87. The RNA molecule according to any one of claims 1 to 39 or 79 to 86, or the chimeric RNA molecule according to any one of claims 40 to 86 which reduces the time to flowering compared to an isogenic plant lacking the RNA molecule or chimeric RNA molecule.

88. The RNA molecule according to any one of claims 1 to 39 or 79 to 86, or the chimeric RNA molecule according to any one of claims 40 to 86 which delays the time to flowering compared to an isogenic plant lacking the RNA molecule or chimeric RNA molecule.

89. The RNA molecule according to any one of claims 1 to 39 or 79 to 88, or the chimeric RNA molecule according to any one of claims 40 to 88, wherein the plant is Arabidopsis, corn, canola, cotton, soybean, alfalfa, lettuce, wheat, barley, rice, legume, Medicago truncatula, sugarbeet or rye.

90. The RNA molecule according to any one of claims 1 to 39 or 79 to 89, or the chimeric RNA molecule according to any one of claims 40 to 89, wherein the plant is genetically unmodified.

91. An isolated and / or exogenous polynucleotide encoding an RNA molecule according to any one of claims 1 to 39 or 79 to 90, or a chimeric RNA molecule according to any one of claims 40 to 90.

92. The polynucleotide of claim 91 which is a DNA construct.

93. The polynucleotide of claim 91 or claim 92 which is operably linked to a promoter capable of directly expression of the RNA molecule in a plant cell.

94. The polynucleotide of claim 93, wherein the promoter is an RNA polymerase promoter such as an RNA polymerase III promoter, an RNA polymerase II promoter, or a promoter which functions in vitro.

95. The polynucleotide according to any one of claims 91 to 94 which encodes an RNA precursor molecule comprising an intron in at least one loop sequence which is capable of being spliced out during transcription of the polynucleotide in a plant cell or in vitro.

96. The polynucleotide according to any one of claims 91 to 94 which comprises a nucleotide sequence set forth in SEQ ID NO:

150.

97. A vector comprising a polynucleotide according to any one of claims 91 to 96.

08. The vector of claim 97 which is a viral vector.

99. A host cell comprising one or more or all of an RNA molecule according to any one of claims 1 to 39 or 79 to 90, a chimeric RNA molecule according to any one of claims 40 to 90, small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, a polynucleotide according to any one of claims 91 to 96, or a vector of claim 97 or claim 98.

100. The host cell of claim 99 which is a plant cell.

101. The polynucleotide claim 93 or claim 94 or the host cell of claim 99 or claim 100 which encodes and / or comprises the chimeric RNA molecule according to any one of claims 40 to 90, wherein the promoter region of the polynucleotide has a lower level of methylation, such as less than about 50%, less than about 40%, less than about 30% or less than about 20%, when compared to the promoter of a corresponding polynucleotide encoding an RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs.

102. A host cell according to any one of claims 99 to 101 which is a plant cell comprising the chimeric RNA molecule or small RNA molecules produced by processing of the chimeric RNA molecule, or both, wherein the chimeric RNA molecule comprises, in 5’ to 3’ order, the first sense ribonucleotide sequence, the first linking ribonucleotide sequence which comprises a loop sequence, and the first antisense ribonucleotide sequence.

103. The host cell according to any one of claims 99 to 102 which comprises at least two copies of the polynucleotide encoding a chimeric RNA molecule according to any one of claims 40 to 90, and wherein i) the level of reduction in the expression or activity of the target RNA molecule in a plant cell is at least the same when compared to if the cell had a single copy of the polynucleotide, and / or ii) the level of reduction in the expression or activity of the target RNA molecule in a plant cell is lower when compared to a corresponding cell comprising an RNA molecule which has a corresponding dsRNA region which is fully basepaired with canonical basepairs.

104. The host cell according to any one of claims 99 to 103, wherein the cell encodes and / or comprises the chimeric RNA molecule according to any one of claims 40 to 90 and the level of sense ribonucleotide sequence in the cell is less than 50 to 99% the level of the antisense ribonucleotide.

105. A plant comprising one or more or all of an RNA molecule according to any one of claims 1 to 39 or 79 to 90, a chimeric RNA molecule according to any one of claims 40 to 90, small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, a polynucleotide according to any one of claims 91 to 96, a vector of claim 97 or claim 98, or a host cell according to any one of claims 99 to 104 which is a plant cell.

106. The plant of claim 105 which comprises the polynucleotide according to any one of claims 91 to 96.

107. The plant of claim 106, wherein the polynucleotide is stably integrated into the genome of the plant.

108. A method of producing an RNA molecule according to any one of claims 1 to 39 or 79 to 90, or a chimeric RNA molecule according to any one of claims 40 to 90, or small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, the method comprising expressing the polynucleotide according to any one of claims 91 to 96 or 101 in a host cell or cell-free expression system.

109. The method of claim 108 which further comprises at least partially purifying the RNA molecule.

110. A method of producing the plant according to any one of claims 105 to 107, the method comprising introducing the polynucleotide according to any one of claims 91 to 96 or 101 into a plant cell so that it is stably integrated into the genome of the cell, and generating the plant from the cell.

111. An extract of a host cell according to any one of claims 99 to 104, wherein the extract comprises the RNA molecule according to any one of claims 1 to 39 or 79 to 90, a chimeric RNA molecule according to any one of claims 40 to 90, or small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, and / or the polynucleotide according to any one of claims 91 to 96 or 101.

112. A composition comprising one or more of an RNA molecule according to any one of claims 1 to 39 or 79 to 90, a chimeric RNA molecule according to any one of claims 40 to 90, small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, a polynucleotide according to any one of claims 91 to 96 or 101, a vector of claim 97 or claim 98, a host cell according to any one of claims 99 to 104, or an extract of claim 111, and one or more suitable carriers.

113. The composition of claim 112 suitable for application to a field.

114. The composition of claim 113, wherein the field comprises plants.

115. The composition according to any one of claims 112 to 114 which further comprises at least one compound which enhances the stability of the RNA molecule, chimeric RNA molecule or polynucleotide and / or which assists in the RNA molecule, chimeric RNA molecule or polynucleotide being taken up by a cell of a plant.

116. The composition of claim 115, wherein the compound is a transfection promoting agent.

117. A method for down-regulating the level and / or activity of a target RNA molecule which modulates plant flowering in a plant, the method comprising delivering to the plant one or more of an RNA molecule according to any one of claims 1 to 39 or 79 to 90, a chimeric RNA molecule according to any one of claims 40 to 90, small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, a polynucleotide according to any one of claims 91 to 96 or 101, a vector of claim 97 or claim 98, a host cell according to any one of claims 99 to 104, an extract of claim 111, or a composition according to any one of claims 112 to 116.

118. The method of claim 117, wherein the target RNA molecule encodes a protein.

119. The method of claim 117 or claim 118, wherein the chimeric RNA molecule, or small RNA molecules produced by processing of the chimeric RNA molecule, or both, are contacted with the cell or plant by topical application to the cell or plant.

120. A method of modulating flowering of a plant, the method comprising delivering to the plant one or more of an RNA molecule according to any one of claims 1 to 39 or 79 to 90, a chimeric RNA molecule according to any one of claims 40 to 90, a polynucleotide according to any one of claims 91 to 96 or 101, a vector of claim 97 or claim 98, a host cell according to any one of claims 99 to 104, an extract of claim 111, or a composition according to any one of claims 112 to 116.

121. The method of claim 120 which results in early flowering of the plant.

122. The method of claim 120 or claim 121, wherein the plant is from Arabidopsis, corn, canola, cotton, soybean, alfalfa, lettuce, wheat, barley, rice, legume, Medicago truncatula, sugarbeet or rye.

123. The method of claim 120 which results in late flowering of the plant.

124. The method of claim 123, wherein the plant is a grass.

125. A method of modulating the flowering time of a plant, or a plant produced from a seed, the method comprising contacting the plant or seed with a composition comprising an RNA molecule which comprises at least one double stranded RNA region, and / or a polynucleotide(s) encoding the RNA molecule, wherein the at least one double stranded RNA region comprises an antisense ribonucleotide sequence which is capable of hybridising to a region of a target RNA molecule which modulates the timing of plant flowering.

126. The method of claim 125, wherein the composition is an aqueous composition.

127. The method of claim 125 or claim 126, wherein the composition comprises a transfection promoting agent.

128. The method according to any one of claims 125 to 127, wherein the method comprises soaking the seed in the composition.

129. The method according to any one of claims 125 to 127, wherein the plant is a seedling, and the method comprises soaking at least a part of the seedling in the composition.

130. The method according to any one of claims 125 to 127, wherein the plant is in a field and the method comprises spraying the composition on at least a part of the plant.

131. The method according to any one of claims 125 to 130, wherein the polynucleotide is a hairpin RNA, a microRNA, a siRNA or an ledRNA.

132. The method according to any one of claims 125 to 131, wherein the plant has an early flowering time when compared to a control plant that has not been applied with the composition.

133. The method according to any one of claims 125 to 131, wherein the plant has a late flowering time when compared to a control plant that has not been applied with the composition.

134. A kit comprising one or more of an RNA molecule according to any one of claims 1 to 39 or 79 to 90, a chimeric RNA molecule according to any one of claims 40 to 90, small RNA molecules (20-24nt in length) produced by processing of the RNA molecule or chimeric RNA molecule, a polynucleotide according to any one of claims 91 to 96 or 101, a vector of claim 97 or claim 98, a host cell according to any one of claims 99 to 104, an extract of claim 111, or a composition according to any one of claims 112 to 116.

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