Novel peptides and use thereof for modulating protein accumulation

Abstract

The present invention relates to novel peptides (cPEPs & altPEPs), to a method for the preparation thereof, and to the use thereof for modulating the accumulation of specific proteins.

Description

[0001] DESCRIPTION

[0002] TITLE: NOVEL PEPTIDES AND THEIR USE TO MODULATE PROTEIN ACCUMULATION

[0003] FIELD OF THE INVENTION

[0004] The present invention relates to novel peptides (cPEPs & altPEPs), their preparation process and their use for modulating the accumulation of specific proteins.

[0005] PREVIOUS ART

[0006] Generally speaking, peptides are short sequences of 2 to about 100 amino acids. They are often highly active molecules, such as hormones or venom compounds.

[0007] In plants, peptides perform many biological functions, such as development or defense mechanisms. Since peptide detection is relatively difficult, only a limited number of peptides have been identified, probably underestimating the quantity and role of peptides in these organisms.

[0008] Most of the peptides characterized in plants likely result from the degradation of functional proteins. However, it has been shown that primary transcripts of microRNAs (miRs) in plants actually contain small open reading frames (miORFs) encoding regulatory peptides, called miPEPs (Lauressergues D et al. Primary transcripts of microRNAs encode regulatory peptides. Nature. 2015 Apr 2;520(7545):90-3.). MiPEPs are produced at the same location as the miRs from which they originate and enhance the transcription of the corresponding pri-miRs. The activity of a miPEP is highly specific to the corresponding miR, allowing the chosen miR to be upregulated without affecting the expression of other miRs. The use of miPEPs can modulate the expression of a gene, if it is regulated by a miR, itself regulated by a miPEP (WO 2015 / 063431).

[0009] BRIEF OVERVIEW

[0010] In this context, the following disclosure provides a universal, and easily exploitable, means for specifically modulating the accumulation of a selected protein in a plant using either a non-natural peptide (invention No. 1; cPEP), i.e., a peptide that is not naturally produced by the plant, or a natural peptide (invention No. 2; altPEP), i.e., a peptide that is naturally produced by the plant.

[0011] Regardless of the invention under consideration, one aspect thereof is to provide a method for preparing and determining a "cPEP" or "altPEP" peptide capable of modulating the accumulation (expression) of a specific protein in a plant cell. A second aspect thereof is to provide a method for modulating the accumulation of a protein in a plant using a cPEP or an altPEP. A third aspect thereof is to provide the use of a cPEP or an altPEP to modulate the accumulation of a protein in a plant. A fourth aspect thereof is to provide a method for promoting, slowing down or preventing the development of a plant. A fifth aspect thereof is to provide cPEP peptides or altPEP peptides for modulating the accumulation of a protein in a plant.Further complementary aspects of these inventions relate to a nucleic acid encoding a cPEP or an altPEP, compositions comprising a cPEP or an altPEP and modified or transgenic plants comprising a cPEP or an altPEP.

[0012] DETAILED DESCRIPTION

[0013] Considering the first invention (cPEP), a first aspect thereof relates to a method for preparing and determining a cPEP, said cPEP: having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids; being capable of modulating the accumulation of a protein in a plant cell; and not being capable of modulating the accumulation of the mRNA encoding said protein, said method comprising: a. a step of determining the nucleic acid sequence of the messenger RNA (mRNA) encoding said protein; b. a step of determining within this mRNA the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame encoding said protein; c.a step of determining within this nucleic acid sequence naturally translated in said plant cell a fragment thereof, said fragment having a size of 3n nucleotides, n being from 4 to 70, in particular n being from 4 to 41, and said fragment having a size smaller than that of the nucleic acid sequence naturally translated in said plant cell; d. a step of producing the peptide encoded by said fragment; and e. a comparison step:.

[0014] - between the accumulation of said protein in a plant cell in the presence of said peptide and the accumulation of said protein in a plant cell of the same type in the absence of said peptide; and / or

[0015] - between the phenotype of a plant in the presence of said peptide and the phenotype of a plant of the same type in the absence of said peptide, in which:

[0016] - a difference in the amount of said protein in the presence of said peptide compared to the amount of said protein in the absence of said peptide; and / or

[0017] - a difference in the phenotype in the presence of said peptide compared to the phenotype in the absence of said peptide, indicates that said peptide is a cPEP capable of modulating the accumulation of said protein in a plant cell.

[0018] The present invention is based on the unexpected observation made by the Inventors that it is possible to specifically modulate the accumulation of a protein using a particular peptide not produced naturally, the sequence of which corresponds to the (artificial) translation of a fragment of the messenger RNA (mRNA) coding for said protein, said fragment being chosen from the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame coding for said protein.

[0019] In the invention, the term “cPEP” (complementary peptide) designates an artificial peptide capable of specifically modulating the accumulation of a protein once introduced into a plant cell.

[0020] According to the invention, a cPEP is not naturally present in a plant cell. This means that the plant cell contains the information of the cPEP but does not contain the nucleic sequence capable of allowing its expression. Only the peptide sequence of the cPEP can be deduced from the sequence of the mRNA encoding the said protein whose accumulation is to be modulated. A cPEP is only present in a plant cell once it has been introduced in the form of a peptide or in the form of a nucleic acid encoding the said peptide.

[0021] The specificity of cPEP for a target protein (or a target gene) is determined by its amino acid sequence. Indeed, the sequence of a cPEP corresponds to the in silico (artificial) translation of a fragment of the mRNA coding for said protein, said fragment being chosen from the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame coding for said protein.

[0022] The peptide sequence of a cPEP can therefore be determined from a fragment of the mRNA coding for said protein by applying, from the first nucleotide of said fragment, the genetic code assigning each triplet of nucleotides a specific amino acid (AUC = Isoleucine, ACA = Threonine, etc.).

[0023] In the invention, the fragment of the mRNA used to determine the sequence of the cPEP can be selected from the three reading frames existing on the mRNA sequence. In other words, a fragment can be selected from the reading frames +1, +2 or +3. In this respect, it is possible that all three of the reading frames contain the information of a cPEP as it is possible that only one of the three of the reading frames (the +1, the +2 or the +3) or two of the three of the reading frames (the +1 and the +2, the +1 and the +3, or the +2 and the +3) contain the information of a cPEP.

[0024] In the invention, the term "reading frame" designates the grouping of nucleotides constituting a nucleic acid sequence into consecutive triplets (or codons), which follow one another without interruption or overlap.

[0025] Generally, cPEPs are 4 to 70 amino acids in size, particularly 4 to 41 amino acids in size, particularly 5 to

[0026] 40 amino acids, 7 to 20 amino acids or more particularly a size of 8 to 15 amino acids. Therefore, the sequence of a cPEP corresponds to the translation of a fragment of 4 to 70 nucleotide triplets, in particular a fragment of 4 to

[0027] 41 nucleotide triplets, in particular a fragment comprising from 5 to 40 nucleotide triplets, from 7 to 20 nucleotide triplets or more particularly a fragment comprising from 8 to 15 nucleotide triplets.

[0028] In other words, the sequence of a cPEP corresponds to the translation into amino acids of a fragment of “3n” nucleotides of the mRNA of the target protein, n being from 4 to 70, in particular from 4 to 41, in particular from 5 to 40, from 7 to 20 or more particularly from 8 to 15.

[0029] For example, if n is equal to 5, the cPEP has a size of 5 amino acids and corresponds to the translation of a fragment of 15 (= 3 x 5) nucleotides. For example, if n is equal to 40, the cPEP has a size of 40 amino acids and corresponds to the translation of a fragment of 120 (= 3 x 40) nucleotides. For example, if n is equal to 70, the cPEP has a size of 70 amino acids and corresponds to the translation of a fragment of 210 (= 3 x 70) nucleotides. Etc.

[0030] The cPEPs are 4, 5, 6, 7, 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, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 or 70 amino acids, and correspond respectively to the translation of fragments of 12, 15, 18, 21, 24, 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 96, 99, 102, 105, 108, 111, 114, 117, 120, 123, 126, 129, 132, 135, 138, 141, 144, 147, 150, 153, 156, 159, 162, 165, 168, 171, 174, 177, 180, 183, 186, 189, 192, 195, 198, 201, 204, 207 or 210 nucleotides.

[0031] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein said fragment has a size of 3n nucleotides, n being comprised: from 4 to 41; from 5 to 40; from 7 to 20; or from 8 to 15.

[0032] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein said peptide has a size selected from: 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26,

[0033] 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,

[0034] 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 and 70 amino acids.

[0035] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein said cPEP has a size smaller than that of said protein (i.e. that of which the cPEP modulates the accumulation).

[0036] As mentioned above, cPEPs have the ability to specifically modulate the accumulation of a protein without impacting the accumulation of its corresponding mRNA. In other words, adding a cPEP to a plant cell does not change the amount of mRNA that can express the protein it regulates, but only the amount of the protein itself.

[0037] According to the invention, the term "protein" designates an amino acid sequence whose information is encoded by a gene present in the genome of a plant cell. By "gene" is therefore meant, in particular, the nucleic acid sequence necessary for the synthesis of said protein. Also, a gene comprises more than the nucleotides encoding the amino acid sequence of the protein. For example, a gene includes the DNA sequences necessary for the synthesis of a pre-messenger (pre-mRNA), which is then matured by the cellular machinery into a messenger RNA (mRNA). The latter can then be translated, via the ribosomes, into a protein.

[0038] From the above, it is understood that pre-messenger RNA (pre-mRNA) has not undergone splicing and is likely to contain introns, while mature messenger RNA (mRNA) may have undergone splicing and contains only exons.

[0039] To prepare a cPEP capable of modulating the accumulation of a protein, it is necessary to translate a fragment of the mRNA coding for said protein, said fragment being chosen from the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame coding for said protein, which does not include either the 5'-UTR region or the 3'-UTR region of the mRNA.

[0040] In the invention, the "modulation" of the accumulation of a protein means either an increase in the accumulation of said protein ( / .e. an increase in the amount of protein in the plant cell), or a decrease in the accumulation of said protein ( / .e. a decrease in the amount of protein in the plant cell). In other words, an embodiment of the invention relates to the method for preparing and determining a cPEP as described above, in which said modulation of the accumulation of said protein induced by said cPEP is: a decrease in the accumulation of said protein; or an increase in the accumulation of said protein.

[0041] The increase and decrease in the accumulation of said protein can be measured and monitored using methods well known to those skilled in the art, such as coupling the protein to a marker via the use of particular expression cassettes, or a Western blot. In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein in step e., the amount of protein in the presence of said peptide is greater than the amount of protein in the absence of said peptide. In other words, in the presence of a cPEP promoting the increase in the accumulation of the protein, the translation of the corresponding mRNA is increased, which leads to a greater production of the protein without the amount of said mRNA being modified.

[0042] In another embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein in step e., the amount of protein in the presence of said peptide is less than the amount of protein in the absence of said peptide. In other words, in the presence of a cPEP promoting the reduction of the accumulation of the protein, the translation of the corresponding mRNA is reduced (inhibited), which leads to a lower production of the protein without the amount of said mRNA being modified.

[0043] In the invention, although the fragment of the mRNA encoding said cPEP is located within the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame encoding said protein, said fragment as such is not naturally translated in said plant cell. This is the case regardless of the reading frame used. The existence of a cPEP within said plant cell is therefore artificial and originates from a human action. For this, it is possible either to artificially introduce said cPEP as such, or to introduce an expression cassette comprising the nucleic acid sequence encoding said cPEP and the means for expressing it in said plant cell.

[0044] In the invention, the nucleic acid sequence naturally translated in said plant cell, which comprises a fragment carrying the information of a cPEP, is a region of the mRNA referred to as "coding", that is to say that it corresponds to a region of the mRNA which codes all or part of the functional protein. This sequence therefore corresponds to the main open reading frame, which codes the protein whose accumulation is to be modulated.

[0045] In the invention, the terms "open reading frame" and "ORF" (open reading frame) are equivalent, and can be used interchangeably. They correspond to a sequence of nucleotides (nucleic acids) in a DNA or RNA molecule that can potentially encode a peptide or a protein: said open reading frame begins with a START codon (the START codon generally encoding a methionine), followed by a series of codons (each codon encoding an amino acid), and ends with a STOP codon (the STOP codon not being translated). The coding region of the mRNA therefore corresponds to the genetic sequence delimited by the START codon or initiation codon (most often encoding a methionine) at the 5' end and by the STOP codon at the 3' end.The coding region of mRNA therefore does not include intronic sequences that may be present in the sequence of a gene or pre-messenger RNA (pre-mRNA), nor the 5'UTR and 3'UTR regions, because these are not translated and therefore do not encode part of the functional protein of the gene.

[0046] In the invention, the sequence of a cPEP is determined by performing an (artificial) translation of a fragment of the mRNA of the protein whose accumulation is to be modulated, said fragment being chosen from the (coding) nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame coding said protein. Also, the same nucleic acid sequence naturally translated in said plant cell can give different cPEPs depending on the fragment of the mRNA chosen. Furthermore, this same mRNA fragment can also give different cPEPs depending on the reading frame used to translate it (artificially), i.e. depending on the grouping of the nucleotides of the sequence into consecutive triplets. Indeed, and as previously mentioned, a translation can be carried out in the three different reading frames, thus potentially leading to three different cPEPs.

[0047] According to the invention, the reading frame “+1” corresponds to the reading frame determined by the initiation codon of the protein, i.e. the START codon of the open reading frame used naturally for the translation of the mRNA. In other words, in the case of an mRNA fragment corresponding to a coding region and translated according to the reading frame +1, the cPEP obtained has a sequence identical to that of a fragment of the amino acid sequence of the protein naturally encoded by said mRNA.

[0048] The “+2” and “+3” reading frames correspond to reading frames that are not (or are little) used naturally for the translation of mRNA. According to the invention, the “+2” reading frame corresponds to the reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame used naturally for the translation of mRNA and the protein it encodes. According to the invention, the “+3” reading frame corresponds to the reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame used naturally for the translation of mRNA and the protein it encodes.

[0049] Generally, in the case of an mRNA fragment corresponding to a coding region and translated according to the +2 or +3 reading frame, the cPEPs obtained have a sequence different from that of a fragment of the amino acid sequence of the protein naturally encoded by said mRNA. In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, in which said fragment lacks: the initiator codon AUG encoding an initiator methionine; or a STOP codon chosen from the codons: UAG, UGA and UAA, and in which said fragment is chosen: either in the same reading frame as the open reading frame encoding said protein; or in a reading frame shifted by one or two nucleotides relative to the open reading frame encoding said protein.

[0050] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, in which said fragment lacks: the initiator codon AUG coding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and in which said fragment is chosen: either in the same reading frame as the open reading frame coding said protein; or in a reading frame shifted by one or two nucleotides relative to the open reading frame coding said protein.

[0051] It is therefore understood that a cPEP, according to the embodiments above, comprises either an AUG codon (and no STOP codon), or a STOP codon (and no AUG codon), or neither of these two elements. In this case, it is the person skilled in the art who adds, if necessary, the missing element or these missing elements to allow, in a non-limiting manner, either to produce a cPEP in vitro by means of, for example, a microorganism and then to use it (in a composition for example), or to introduce the sequence and the means of expressing it via a vector in a plant cell or a plant.

[0052] In one embodiment, the invention therefore relates to the method for preparing and determining a cPEP as described above, in which said fragment comprises an initiator codon AUG coding an initiator methionine and is devoid of a STOP codon chosen from the codons: UAG, UGA and UAA. The invention also relates to the method for preparing and determining a cPEP as described above, in which said fragment is devoid of an initiator codon AUG coding an initiator methionine and comprises a STOP codon chosen from the codons: UAG, UGA and UAA.In view of the above, it is understood that in another embodiment, the invention relates to the method for preparing and determining a cPEP as described above, said cPEP: having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids; being capable of modulating the accumulation of a protein in a plant cell; and not being capable of modulating the accumulation of the mRNA encoding said protein, said method comprising: a. a step of determining the nucleic acid sequence of the messenger RNA (mRNA) encoding said protein; b. a step of determining within this mRNA the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame encoding said protein; c.a step of determining within this nucleic acid sequence naturally translated in said plant cell a non-naturally translated fragment thereof, said non-naturally translated fragment:.

[0053] - having a size of 3n nucleotides, n being from 4 to 70, in particular n being from 4 to 41,

[0054] - having a size smaller than that of the nucleic acid sequence naturally translated in said plant cell,

[0055] - lacking the initiator codon AUG coding an initiator methionine and / or a STOP codon chosen from the codons: UAG, UGA and UAA, and

[0056] - being chosen either in the same reading frame as the open reading frame encoding said protein, or in a reading frame shifted by one or two nucleotides relative to the open reading frame encoding said protein; d. a step of producing the peptide encoded by said non-naturally translated fragment; and e. a comparison step:

[0057] - between the accumulation of said protein in a plant cell in the presence of said peptide and the accumulation of said protein in a plant cell of the same type in the absence of said peptide; and / or

[0058] - between the phenotype of a plant in the presence of said peptide and the phenotype of a plant of the same type in the absence of said peptide, in which:

[0059] - a difference in the amount of said protein in the presence of said peptide compared to the amount of said protein in the absence of said peptide; and / or

[0060] - a difference in the phenotype in the presence of said peptide compared to the phenotype in the absence of said peptide, indicates that said peptide is a cPEP capable of modulating the accumulation of said protein in a plant cell.

[0061] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, in which the translation of the mRNA fragment is carried out in the same reading frame as the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the method for preparing and determining a cPEP as described above, in which the translation of the mRNA fragment is carried out in the reading frame determined by the initiation codon of the open reading frame of said protein.

[0062] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the method for preparing and determining a cPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the method for preparing and determining a cPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the method for preparing and determining a cPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein said cPEP is a hydrophobic peptide or a hydrophilic peptide. In particular, the invention relates to the method for preparing and determining a cPEP as described above, wherein said cPEP is a hydrophobic peptide. By "hydrophobic peptide" is meant a peptide whose amino acid sequence comprises more than 50% hydrophobic amino acids. By "more than 50%" is meant that the amino acid sequence comprises more than 55%, more than 60%, more than 65%, more than 70%, more than 75% or more than 80% hydrophobic amino acids. By "more than 50%" is also meant that the amino acid sequence comprises at least 51%, at least 56%, at least 61%, at least 66%, at least 71%, at least 76% or at least 81% of hydrophobic amino acids.By "hydrophobic amino acids" is meant amino acids chosen from: alanine (Ala / A), isoleucine (Ile / I), leucine (Leu / L), methionine (Met / M), phenylalanine (Phe / F), tryptophan (Trp / W), tyrosine (Tyr / Y) and valine (Val / V).

[0063] In particular, the invention also relates to the method for preparing and determining a cPEP as described above, wherein said cPEP is a hydrophilic peptide. By "hydrophilic peptide" is meant a peptide whose amino acid sequence comprises more than 50% hydrophilic amino acids. By "more than 50%" is meant that the amino acid sequence comprises more than 55%, more than 60%, more than 65%, more than 70%, more than 75% or more than 80% hydrophilic amino acids. By "more than 50%" is also meant that the amino acid sequence comprises at least 51%, at least 56%, at least 61%, at least 66%, at least 71%, at least 76% or at least 81% hydrophilic amino acids. By "hydrophilic amino acids" is meant amino acids chosen from: aspartic acid (Asp / D), glutamic acid (Glu / E), arginine (Arg / R), asparagine (Asn / N), glutamine (Gin / Q), histidine (His IH), lysine (Lys / K), serine (Ser / S) and threonine (Thr / T).。

[0064] In one embodiment, the invention relates to a method for preparing and determining a cPEP, said cPEP: having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids; being capable of modulating the accumulation of a protein in a plant cell; and not being capable of modulating the accumulation of the mRNA encoding said protein, said method comprising: a. a step of determining the nucleic acid sequence of the messenger RNA (mRNA) encoding said protein; b. a step of determining within this mRNA one of the nucleic acid sequences comprising two contiguous parts:

[0065] - a part located within a nucleic acid sequence known to be non-coding ( / .e. not naturally translated, eg 5'IITR or 3'IITR), and

[0066] - a part located within a nucleic acid sequence deemed to be coding ( / .e. naturally translated, e.g. exon); c. a step of determining within this nucleic acid sequence comprising two contiguous parts a fragment thereof, said fragment having a size of 3n nucleotides capable of being translated via the genetic code into a peptide, n being from 4 to 70, in particular n being from 4 to 41; d. a step of producing said peptide; and e. a step of comparing:

[0067] - between the accumulation of said protein in a plant cell in the presence of said peptide and the accumulation of said protein in a plant cell of the same type in the absence of said peptide; and / or

[0068] - between the phenotype of a plant in the presence of said peptide and the phenotype of a plant of the same type in the absence of said peptide, in which:

[0069] - a difference in the amount of said protein in the presence of said peptide compared to the amount of said protein in the absence of said peptide; and / or

[0070] - a difference in the phenotype in the presence of said peptide compared to the phenotype in the absence of said peptide, indicates that said peptide is a cPEP capable of modulating the accumulation of said protein in a plant cell.

[0071] According to the invention, a cPEP can be produced by any type of means accessible to those skilled in the art.

[0072] In a non-limiting manner, a cPEP can be produced both synthetically and by recombinant expression in homologous or heterologous systems. The cPEP thus produced can then be introduced into a cell to modulate the accumulation of a target protein. In a non-limiting manner, it is also possible to produce a cPEP directly in the plant cell containing the target protein, by artificially introducing into it a nucleic acid (such as an expression vector) encoding said cPEP.

[0073] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein, in step d., the production of said peptide is carried out by peptide synthesis or by recombinant expression.

[0074] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein, in step d., the production of said peptide is carried out using a nucleic acid encoding said peptide introduced into a cell.

[0075] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein, in step e., the production of said peptide is carried out using a nucleic acid encoding said peptide introduced into said plant cell or into said plant.

[0076] In one embodiment, the invention relates to a method for preparing and determining a cPEP as described above, wherein, in step e., said peptide is brought into contact with said plant cell or in said plant.

[0077] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein, in step e., said peptide is present in said plant cell or in said plant following the expression of a nucleic acid encoding said peptide in said plant cell or in said plant.

[0078] In view of the above, it is understood that another embodiment of the invention relates to the method for preparing and determining a cPEP as described above, in which, in step e., the presence of said peptide in said plant cell or in said plant results:

[0079] - the introduction of a nucleic acid sequence encoding said peptide and comprising the means for expressing it; or

[0080] - the introduction of an amino acid sequence corresponding to said peptide.

[0081] A cPEP can be used to modulate the accumulation of a protein that is naturally occurring (i.e. endogenous) or not (i.e. exogenous) in said plant cell or plant. A "protein naturally occurring in a plant cell or plant" means an endogenous protein encoded by a gene present in the genome of the plant cell or plant without the need for direct or indirect human intervention.

[0082] A “protein that is not naturally present in a plant cell or in a plant” corresponds to an exogenous protein encoded by a nucleic acid sequence present in the genome of the plant cell or of the plant which required the intervention of a human being and the use of means known to those skilled in the art. Such a nucleic acid sequence may come from the same species of plant or from another species of plant.

[0083] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is of endogenous origin in said plant cells or said plants used in step e.

[0084] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, in which said protein is of exogenous origin in said plant cells or said plants used in step e., said plant cells or said plants used in step e. then comprising a nucleic acid sequence allowing the expression of said protein.

[0085] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, in which the accumulation of said protein is determined via the implementation of a technique chosen from: Western blot, measurement of enzymatic activity, mass spectrometry and translational fusion. In particular, the invention relates to the method for preparing and determining a cPEP as described above, in which the accumulation of said protein is determined via the implementation of a Western blot.

[0086] The inventors have surprisingly found that the use of cPEPs makes it possible to modify the phenotypes of a plant visible at the macroscopic scale. It is therefore entirely possible to use the latter to affirm (or refute) that the peptide determined in steps a., b. and c., and possibly produced in step d. is a cPEP (or not). This is also what the so-called phenotypic comparison alternative implemented in step e allows. For example, if the peptide determined on the mRNA of a protein involved in the size of the stem of a plant causes an increase, or a decrease, in the size of the stem of a plant treated with the latter compared to an untreated plant, this means that said peptide is a cPEP capable of modulating the accumulation of said protein in the size of the stem.In the invention, the term "plant" refers generally to: a set of plant cells organized in whole or in part of a plant whatever its stage of development (including the plant in the form of a seed or young shoot); to one or more organs of the plant (such as for example the leaves, the roots, the stem, the flowers); to one or more cells of the plant; or to a mass of cells of the plant (eg a callus).

[0087] In the invention, the term "phenotype" designates, in a non-limiting manner, the characteristics visible on a macroscopic scale such as the number of lateral roots, the number of leaves, the size of the stem, the duration of flowering and the resistance to stress.In one embodiment, the invention therefore relates to the method for preparing and determining a cPEP as described above, wherein said protein is involved in at least one plant phenotype selected from: size, shape, surface area, volume, mass and number of leaves; size, shape, surface area, volume, mass and number of flowers; size of the stem (or floral stalk); root biomass; number, length and branching level of the roots; earliness of germination; earliness of budding; earliness of floral induction (or floral transition); germination vigor and duration of juvenile phase; duration of flowering; resistance to biotic stress; resistance to abiotic stress; and number of cells.

[0088] According to the invention, a protein is "involved in a phenotype" if a modification of its accumulation is associated with a modification of said phenotype. In other words, a protein is involved in a phenotype if it intervenes in the characteristic(s) corresponding to said phenotype.

[0089] In view of the above, it is understood that an object of the invention is the method for preparing and determining a cPEP as described above, in which the phenotype observed in step e. is chosen from: the size, shape, surface area, volume, mass and number of leaves; the size, shape, surface area, volume, mass and number of flowers; the size of the stem (or floral stalk); the root biomass; the number, length and level of branching of the roots; the earliness of germination; the earliness of budding; the earliness of floral induction (or floral transition); the germination vigor and the duration of the juvenile phase; the duration of flowering; the resistance to biotic stress; the resistance to abiotic stress; and the number of cells.

[0090] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, said cPEP: having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids; being capable of modulating the accumulation of a protein in a plant cell; and not being capable of modulating the accumulation of the mRNA encoding said protein, and wherein said plant cell ( / .e.celle dans laquelle on souhaite modular l'accumulation d'une protéine) appartient à une espèce végétale choisie parmi : Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis halleri, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (rapeseed), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eutrema salsugineum, Glycine max (soybean), Gossypium raimondii, Gossypium spp. (coton), Hordeum vulgare (orge), Lollium spp., Lotus japonicus (lotier), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tabac), Oryza sativa (riz), Pisum sativum (pois), Raphanus sativus, Solanum lycopersicum (tomate), Solanum melongena (aubergine), Solanum tuberosum (pomme de terre), Thellungiella halophila, Theobroma cacao, Triticum spp.(wheat), Vitis vinifera (vine) and Zea mays (corn).

[0091] In one embodiment, the invention relates to the process of preparing and determining a cPEP as previously described, wherein said plant cells or plants are used in step e. belong to: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis halleri, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera strict, Brachypodium distachyon, Brassicaca, Brassicacea, Brassicacea, older turnip (rape), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eutrema salsugineum, Glycine max (soybean), Gossypium raimondii, Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (trefoil), Medicago sativa (alfalfa), Medicago truncatula (alfalfa), Nicotiana benthamiana (tobacco), Oryza sativa (rice), Pisum sativum (pea), Raphanus sativus, Solanum lycopersicum (tomato), Solanum melongena (eggplant), Solanum tuberosum (potato), Thellungiella halophila, Theobroma cacao, Triticum spp. (wheat), Vitis vinifera (vine) and Zea mays (corn).

[0092] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, in which said plant cell (i.e. the one in which it is desired to modulate the accumulation of a protein) is a cell of an algae.

[0093] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein said plant cells or said plants used in step e belong to an algae.

[0094] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, in which said protein is encoded by a gene selected from: Aae15 (Acyl-activating enzyme 15), Aae16 (AMP-dependent synthetase and ligase family protein), Abcg11 (White-brown complex-like protein), Abdcg34 (ABC transporter G family member 34), Acc1 (Acetyl-CoA Carboxylase), Agb1 (GTP binding protein beta 1), Als (Acetolactate synthase (chloroplastic)), Anac076 (NAC domain-containing protein 76), Apg9 (Autophagy 9), Arlbl (GTP-binding protein 1), Arr1 (Two-component response regulator ARR1), Arr5 (Two-component response regulator ARR5), Arr6 (Two-component response regulator ARR6), At59 (Pedate lyase family protein), Bak1 (Brassinosteroid insensitive 1 -associated receptor kinase 1), Bccpl (Acetyl-CoA Carboxylase (chloroplastic) subunit 1), Bccp2 (Acetyl-CoA Carboxylase (chloroplastic) subunit 2), Bril (Brassinosteroid insensitive 1),Bzo2h3 (bZIP transcription factor family protein), Cesa6 (Cellulose synthase A catalytic subunit 6), Cipk3 (CBL-intera ing protein kinase 3), Cks1 (Cyclin-dependent kinases regulatory subunit 1), Cobl8 (COBRA-like protein 8 precursor), Coil (Coronatine-insensitive protein 1), Cpk3 (Calcium-dependent protein kinase 3), Crk34 (Cysteine-rich receptor-like protein kinase 34), Cyp705a18 (Cytochrome P450, family 705, subfamily A, polypeptide 18), Cyp71b26 (Cytochrome P450, family 71, subfamily B, polypeptide 26), Cyp78a8 (Cytochrome P450, family 78, subfamily A, polypeptide 8), Cyp97b3 (Cytochrome P450, family 97, subfamily B, polypeptide 3), Dell (Endoribonuclease Dicer homolog 1), Dur3 (Urea-proton symporter DUR3), Ein2 (Ethylene-insensitive protein 2), Emb 175 (Pentatricopeptide repeat-containing protein), Emb2726 (Elongation factor Ts family protein), Emb9 (Di hydrofolate synthetase), Epsps (5-enolpyruvylshikimate-3-phosphate (chloroplastic)), Fnr1 (Ferredoxin-NADP[+]-oxidoreductase 1),Fve (Transducin family protein / WD-40 repeat family protein), Ga2ox7 (Gibberellin 2-beta-dioxygenase 7), Gape (Glyceraldehyde-3-phosphate dehydrogenase), Gcn2 (ABC transporter family protein), Gdi2 (Guanosine nucleotide diphosphate dissociation inhibitor 2), Gln2 (Glutamine synthetase (chloroplastic)), Gsl3 (Callose synthase 2), Hag5 (Histone acetyltransferase of the MYST family 2), Hda18 (Histone deacetylase 18), Hexol (Beta-hexosaminidase 1), Hppd (4- hydroxyphenyl-pyruvate-dioxygenase), Hsl1 (B3 domain-containing transcription repressor VAL2), Iaa31 (lndole-3-acetic acid inducible 31), Iqd28 (IQ-domain 28), Jac1 (J-domain protein required for chloroplast accumulation response 1), Jar1 (Jasmonoyl-L-amino acid synthetase), Kp1 (Kinesin-like protein 1), Lrx2 (Leucine-rich repeat / extensin 2), Mapkkk3 (Mitogen-activated protein kinase kinase kinase 3), Mapkkk5 (Mitogen-activated protein kinase kinase kinase 5), Mfp2 (Multifunctional protein 2), Mrb1 (Transmembrane protein,putative (DUF3537)), Nsp1 (Nodulation signaling pathway 1), Pds (Phytoene desaturase (chloroplastic)), Pen3 (Phosphatidylinositol 3,4,5-trisphosphate 3-phosphatase and protein- tyrosine-phosphatase), Phyb (Phytochrome B), Pif3 (Phytochrome interacting factor 3), Pizza (Brassinosteroid-related acyltransferase 1), Ppoxl (Protoporphyrinogen oxidase (chloroplastic) 1), Ppox2 (Protoporphyrinogen oxidase (chloroplastic) 2), Prp39 (Tetratricopeptide repeat (TPR)-like superfamily protein), PsbA (Photosystem II D1 protein), Pskrl (Phytosulfokin receptor 1), Rd21 (Granulin repeat cysteine protease family protein), Ringl (RING / U-box superfamily protein), Rosi (DNA glycosylase / AP lyase ROS1), Rpt4a (26S proteasome regulatory subunit 10B homolog A), Sfr6 (Mediator of RNA polymerase II transcription subunit 16), Shr (Protein SHORT-ROOT), Shy2 (Auxin-responsive protein IAA3), Ski (EIN2-like protein, nramp transporter), Sps1 (Sucrose phosphate synthase 2F), Spt (Transcription factor SPATULA),Stn8 (Serine / threonine-protein kinase), Tap46 (PP2A regulatory subunit TAP46), Topp6 (Serine / threonine-protein phosphatase PP1 isozyme 7), TubB6 (Tubulin), TubB8 (Tubulin), Ubala (RNA-binding (RRM / RBD / RNP motifs) family protein), Vim3 (E3 ubiquitin-protein ligase), Sgr1 (Magnesium dechelatase), Abi5 (Abscisic acid (ABA)-insensitive 5), Hsp101 (Heat shock protein 101), Rh10 (ATP-dependent RNA helicase) et Wus (WUSCHEL).,

[0095] In particular, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by a gene selected from: Cpk3, Dell and Nsp1. In particular, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by the Cpk3 gene. In particular, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by the Dell gene. In particular, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by the Nsp1 gene.

[0096] The genes Aae15, Aae16, abcg11, Abdcg34, Acc1, Agb1, Als, Anac076, Apg9, Arlbl, Arr1, Arr5, Arr6, At59, Bak1, Bccpl, Bccp2, Bri1, Bzo2h3, Cesaô, Cipk3, Cks1, Cobl8, Coi1, Cpk3, Crk34, Cyp705a18, Cyp71b26, Cyp78a8, Cyp97b3, Dell, Dur3, Ein2, Emb175, Emb2726, Emb9, Epsps, Fnr1, Eve, Ga2ox7, Gapc, Gcn2, Gdi2, Gln2, Gsl3, Hag5, Hda18, Hexol, Hppd, Hsl1, Iaa31, Iqd28, Jac1, Jar1, Kp1, Lrx2, Mapkkk3, Mapkkkô, Mfp2, Mrb1, Nsp1, Pds, Pen3, Phyb, Pif 3, Pizza, Ppoxl, Ppox2, Prp39, PsbA, Pskrl, Rd21, Ringl, Rosi, Rpt4a, Sfr6, Shr, Shy2, Ski, Sps1, Spt, Stn8, Tap46, Toppô, TubB6, TubB8, Ubala, Vim3, Sgr1, Abi5, Hsp101, Rh10 and l / l / us refer to the proteins indicated in parentheses. Of course, the invention also relates to homologous and / or similar genes which may have different names. For example, in A. thaliana the Gsl3 gene encoding callose synthase 2 is also called Cals2.

[0097] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NO: 1 (ORF of the Aae15 protein, A. thaliana), SEQ ID NO: 2 (ORF of the Aae16 protein, A. thaliana), SEQ ID NO: 3 (ORF of the abcg11 protein, A. thaliana), SEQ ID NO: 4 (ORF of the Abdcg34 protein, A. thaliana), SEQ ID NO: 5 (ORF of the Acc1 protein, A. thaliana), SEQ ID NO: 6 (ORF of the Agb1 protein, A. thaliana), SEQ ID NO: 7 (ORF of the Als protein, A. thaliana), SEQ ID NO: 8 (ORF of the Anac076 protein, A. thaliana), SEQ ID NO: 9 (ORF of the Apg9 protein, A. thaliana), SEQ ID NO: 10 (ORF of the Arlbl protein, A. thaliana), SEQ ID NO: 11 (ORF of the Arr1 protein, A.thaliana), SEQ ID NO: 12 (ORF of Arr5 protein, A. thaliana), SEQ ID NO: 13 (ORF of Arr6 protein, A. thaliana), SEQ ID NO: 14 (ORF of At59 protein, A. thaliana), SEQ ID NO: 15 (ORF of Ba protein, A. thaliana), SEQ ID NO: 16. (ORF of the Bccpl protein, A. thaliana), SEQ ID NO: 17 (ORF of the Bccp2 protein, A. thaliana), SEQ ID NO: 18 (ORF of the Bri1 protein, A. thaliana), SEQ ID NO: 19 (ORF of the Bzo2h3 protein, A. thaliana SEQ ID NO: 20), the NOF protein (ORF of A. thaliana). Cesa6, A. thaliana), SEQ ID NO: 21 (ORF of the protein Cipk3, A. thaliana), SEQ ID NO: 22 (ORF of the protein Cks1, A thaliana), SEQ ID NO: 23 (ORF of the protein Cobl8, A thaliana), SEQ ID NO: 24 (ORF of the protein Cobl8, A. thaliana), ID NO: 25 (ORF of Coil protein, A. thaliana), SEQ ID NO : 26 (ORF of Cpk3 protein, A. thaliana), SEQ ID NO : 27 (ORF of Cpk3 protein, A. hypochondriacus), SEQ ID NO : 28 (ORF of Cpk3 protein, B.distachyori), SEQ ID NO: 29 (ORF of Cpk3 protein, B. distachyori), SEQ ID NO: 30 (ORF of Cpk3 protein, G. max), SEQ ID NO: 31 (ORF of Cpk3 protein, G. max), SEQ ID NO: 32 (ORF of Cpk3 protein, G. max), SEQ ID NO: 32 (ORF of Cpk3 protein, G. max). : 33 (ORF of Cpk3 protein, G. max), SEQ ID NO: 34 (ORF of Cpk3 protein, O. sativa), SEQ ID NO: 35 (ORF of Cpk3 protein, O. sativa), SEQ ID NO: 36 (ORF of Cpk3 protein, S. sativa), SEQ ID NO: Cpk3 protein, Z. mays), SEQ ID NO: 38 (ORF of Cpk3 protein, Z. mays), SEQ ID NO: 39 (ORF of Cpk3 protein, Z. mays), SEQ ID NO: 40 (ORF of Cpk3 protein, B. rapa), SEQ ID NO: 41 (ORF of Cpk3 protein, B. rapa), SEQ ID NO: 41 (ORF of Cpk3 protein, rapa). SEQ ID NO : 42 (ORF of Cpk3 protein, H. vulgare), SEQ ID NO : 43 (ORF of Cpk3 protein, H. vulgare), SEQ ID NO : 44 (ORF of Cpk3 protein, S. tuberosum), SEQ ID NO : 45 (ORF of Cpk3 protein, S. tuberosum), SEQ ID NO : 46 (ORF of Cpk3 protein, A. palm). (ORF of Cpk3 protein, Mtruncatula), SEQ ID NO : 47 (ORF of Cpk3 protein, M. truncatula), SEQ ID NO : 48 (ORF of Cpk3 protein, T. aestivum), SEQ ID NO : 49 (ORF of Cpk3 protein, T. aestivum), SEQ ID NO : 50 (ORF of Cpk3 protein, T. aestivum), SEQ ID NO : 50 (ORF of Cpk3 protein, T. aestivum). ID NO: 51 (ORF of the Cpk3 protein, T. aestivum), SEQ ID NO: 52 (ORF of the Cpk3 protein, L. perenne), SEQ ID NO: 53 (ORF of the Cpk3 protein, L. perenne), SEQ ID NO: 54 (ORF of the Cpk3 protein, L. perenne), SEQ ID NO: 5 (ORF of the Cpk3 protein, 5). of the Cpk3 protein, L. perenne), SEQ ID NO: 56 (ORF of the Crk34 protein, A. thaliana), SEQ ID NO: 57 (ORF of the Cyp705a18 protein, A. thaliana), SEQ ID NO: 58 (ORF of the protein Cyp71b26, A. thaliana), AQ ID NO: 56 (ORF of the thaliana protein). the Cyp78a8 protein, A. thaliana), SEQ ID NO: 60 (ORF of the Cyp97b3 protein, A. thaliana), SEQ ID NO: 61 (ORF of the Dell protein, A. thaliana), SEQ ID NO: 62 (ORF of the Dell protein, A. thaliana), ID NO: 63 (ORF of the Dell protein, A. thaliana). TO.hypochondriacus), SEQ ID NO: 64 (ORF of the Dell protein, B. distachyon), SEQ ID NO: 65 (ORF of the Dell protein, G. max), SEQ ID NO: 66 (ORF of the Dell protein, G. max), SEQ ID NO: 67 (ORF of the Dell protein, ORF sativa, ORF: 68). Dell protein, S. lycopersicum), SEQ ID NO: 69 (ORF of Dell protein, Z. mays), SEQ ID NO: 70 (ORF of Dell protein, B. rapa), SEQ ID NO: 71 (ORF of Dell protein, H. vulgare), SEQ ID NO: 72 (ORF of Dell protein, S. mays). tuberosum), SEQ ID NO : 73 (ORF of Dell protein, M. truncatula), SEQ ID NO : 74 (ORF of Dell protein, T. aestivum), SEQ ID NO : 75 (ORF of Dell protein, T. aestivum), SEQ ID NO : 76 (ORF of Dell protein, T. aestivum), SEQ ID NO : 77 (ORF of Dell protein, T. aestivum). (ORF of the Dell protein, T. aestivum), SEQ ID NO: 78 (ORF of the Dell protein, L. perenne), SEQ ID NO: 79 (ORF of the Dell protein, L.perenne), SEQ ID NO: 80 (ORF of the protein Dur3, A thaliana), SEQ ID NO: 81 (ORF of the protein Ein2, Æ thaliana), SEQ ID NO: 82 (ORF of the protein Emb175, A. thaliana), SEQ ID NO: 83 (ORF of the protein Emb175, A. thaliana), SEQ ID NO: 84 (ORF of Emb9 protein, A. thaliana), SEQ ID NO: 85 (ORF of Epsps protein, A. thaliana), SEQ ID NO: 86 (ORF of Fnr1 protein, A. thaliana), SEQ ID NO: 87 (ORF of Fve protein, A. thaliana), SEQ ID NO: 8 (ORF of A. thaliana protein). Ga2ox7, A. thaliana), SEQ ID NO: 89 (ORF of Gape protein, N. benthamiana), SEQ ID NO: 90 (ORF of Gcn2 protein, A. thaliana), SEQ ID NO: 91 (ORF of Gdi2 protein, A. thaliana), SEQ ID NO: 92 (ORF of Gdi2 protein, A. thaliana), SEQ ID NO: 92 (ORF of Gdi2 protein, A. thaliana). SEQ ID NO: 93 (ORF of Gsl3 protein, A. thaliana), SEQ ID NO: 94 (ORF of Hag5 protein, A. thaliana), SEQ ID NO: 95 (ORF of Hda18 protein, A. thaliana), SEQ ID NO: 96 (ORF of Hexol protein, A. thaliana), SEQ ID NO: 97 (ORF of thaliana). the Hppd protein, A.thaliana), SEQ ID NO : 98 (ORF of Hsl1 protein, A. thaliana), SEQ ID NO : 99 (ORF of Iaa31 protein, A. thaliana), SEQ ID NO : 100 (ORF of Iqd28 protein, A. thaliana), SEQ ID NO : 101 (ORF of Jacd28 protein, A. thaliana ), SEQ ID NO : 101 (ORF of A. thaliana protein). ID NO: 102 (ORF of the Jar1 protein, A. thaliana), SEQ ID NO: 103 (ORF of the Kp1 protein, A. thaliana), SEQ ID NO: 104 (ORF of the Lrx2 protein, A. thaliana), SEQ ID NO: 105 (ORF of the Mak protein, A. thaliana), SEQ ID NO: A. thaliana. 106 (ORF of the protein Mapkkk5, A. thaliana), SEQ ID NO: 107 (ORF of the protein Mfp2, A. thaliana), SEQ ID NO: 108 (ORF of the protein Mrb1, A. thaliana), SEQ ID NO: 109 (ORF of the protein Nsp1, truncated SEQ1: ID: 10). of the Nsp1 protein, A. thaliana), SEQ ID NO: 111 (ORF of the Nsp1 protein, B. distachyon), SEQ ID NO: 112 (ORF of the Nsp1 protein, G. max), SEQ ID NO: 113 (ORF of the Nsp1 protein, G. max), SEQ ID NO: 114 (ORF of the Nsp1 protein, G. max). OH.sativa), SEQ ID NO : 115 (ORF of the Nsp1 protein, S. lycopersicum), SEQ ID NO : 116 (ORF of the Nsp1 protein, S. lycopersicum), SEQ ID NO : 117 (ORF of the Nsp1 protein, Z. mays), SEQ ID NO : 118 (ORF of the Nsp1 protein, Z. mays), SEQ ID NO : 119 (ORF of the Nsp1 protein, Z. mays), SEQ ID NO : 120 (ORF of the Nsp1 protein, Z. mays), SEQ ID NO : 121 (ORF of the Nsp1 protein, B. rapa), SEQ ID NO : 122 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 123 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 124 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 125 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 126 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 127 (ORF of the Nsp1 protein, H. vulgare), Nsp1, H. vulgare), SEQ ID NO : 128 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 129 (ORF of the Nsp1 protein, S. tuberosum), SEQ ID NO : 130 (ORF of the Nsp1 protein, S. tuberosum), SEQ ID NO : 131 (ORF of the Nsp1 protein, T. aestivum), SEQ ID NO: 132 (ORF of the Nsp1 protein, T.aestivum), SEQ ID NO: 133 (ORF of protein Nsp1, L. perenne), SEQ ID NO: 134 (ORF of protein Nsp1, L. perenne), SEQ ID NO: 135 (ORF of protein Pds, A. thaliana), SEQ ID NO: 136 (ORF of protein thaliana, A. ID3). 137 (ORF of the Phyb protein, A. thaliana), SEQ ID NO: 138 (ORF of the Pif3 protein, A. thaliana), SEQ ID NO: 139 (ORF of the Pizza protein, A thaliana), SEQ ID NO: 140 (ORF of the Ppoxl protein, A. thaliana), SEQ ID NO: 141 (ORF of the IDA protein: Ppox2, A. thaliana), SEQ ID NO: 142 (ORF of the Prp39 protein, A. thaliana), SEQ ID NO: 143 (ORF of the PsbA protein, A. thaliana), SEQ ID NO: 144 (ORF of the Pskrl protein, A. thaliana), SEQ ID NO: 215 (ORF of the Rp39 protein, A. thaliana). A. thaliana), SEQ ID NO: 146 (ORF of the Ringl protein, A. thaliana), SEQ ID NO: 147 (ORF of the Rosi protein, A. thaliana), SEQ ID NO: 148 (ORF of the Rpt4a protein, A. thaliana), SEQ ID NO: 149 (ORF of the Sfr protein, A. thaliana).thaliana), SEQ ID NO : 150 (ORF of the Shr protein, A. thaliana), SEQ ID NO : 151 (ORF of the Shy2 protein, A. thaliana), SEQ ID NO : 152 (ORF of the Ski protein, M. truncatula), SEQ ID NO : 153 (ORF of the Ski protein, A. thaliana ), SEQ ID NO : NO 154 (ORF of the protein Spt, A. thaliana), SEQ ID NO: 155 (ORF of the protein Stn8, A. thaliana), SEQ ID NO: 156 (ORF of the protein Tap46, A. thaliana), SEQ ID NO: 157 (ORF of the protein Topp6, A. thaliana), SEQ ID NO: TubB6 protein, A. thaliana), SEQ ID NO: 159 (ORF of the TubB8 protein, A. thaliana), SEQ ID NO: 160 (ORF of the llbala protein, A. thaliana), SEQ ID NO: 161 (ORF of the Vim3 protein, A. thaliana), SEQ ID NO: 38 (ORF of the Sgr protein (ORF, A. thaliana). , A. thaliana), SEQ ID NO: 382 (ORF of Abi5 protein, A. thaliana), SEQ ID NO: 383 (ORF of Hsp101 protein, A. thaliana), SEQ ID NO: 384 (ORF of Rh10 protein, M. truncatula) and SEQ ID NO: 385 (ORF of Abi5 protein, A. thaliana). thaliana).

[0098] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0099] In particular, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 61 to 79 (Dell).In particular, the invention relates to the method for preparing and determining a cPEP as described above, in which said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0100] By "percentage identity" between two nucleic acid (or amino acid) sequences, we mean a percentage of nucleotides (or amino acid residues) that are identical between the two sequences to be compared, obtained after the best alignment. This percentage is purely statistical and the differences between the two sequences are randomly distributed over the entire length of the sequences. The best alignment (or optimal alignment) is the alignment for which the percentage identity between the two sequences to be compared, as calculated below, is the highest. Sequence comparisons between two nucleic acid (or amino acid) sequences are traditionally performed by comparing these sequences after having aligned them optimally, said comparison being performed by segment or comparison window to identify and compare local regions of sequence similarity.Optimal alignment of sequences for comparison can be performed manually or by means of algorithms and software available to those skilled in the art, for example, the BLAST platform or the MatGat program (Campanella, Bitincka and Smalley, 2003).

[0101] The percentage identity between two sequences is determined by comparing these two optimally aligned sequences by comparison window in which the region of the sequence to be compared may include additions or deletions relative to the reference sequence for optimal alignment between these two sequences. The percentage identity is calculated by determining the number of identical positions for which the nucleotide (or amino acid) is identical between the two sequences, dividing this number of identical positions by the total number of positions in the comparison window and multiplying the result obtained by 100.

[0102] For the purposes of the invention, it is understood in the invention that sequences having “at least 80% identity” with a reference sequence may in particular have at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity with said reference sequence.

[0103] In one embodiment, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385. In one embodiment, the invention also relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0104] In particular, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention relates to the method for preparing and determining a cPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0105] In another embodiment, the invention relates to the procedure for preparing and determining a cPEP as previously described, wherein said peptide sequence is selected from the following sequences: SEQ ID NO: 162 (cPEPcpk3), SEQ ID NO: 163, SEQ ID NO: cPEP NO: : 164 (cPEPnsp1_3), SEQ ID NO : 165 (cPEPnsp1_1), SEQ ID NO : 166 (cPEPnsp1_2), SEQ ID NO : 167 (cPEPnsp1_4), SEQ ID NO : 168 (cPEPnsp1_5), SEQ ID NO : 169 (cPEPnsp1_5), SEQ ID NO : 5 170 (cPEPnspl 20aa), SEQ ID NO : 171 (cPEPnspl 30aa), SEQ ID NO : 172 (cPEPnspl 40aa), SEQ ID NO : 173 (cPEPnspl 60aa), SEQ ID NO : 174 (cPEPnspl SEQa 80a), IDGA : NO SEQ ID NO : 176 (cPEPbril), SEQ ID NO : 177 (cPEPbakl), SEQ ID NO : 178 (cPEPshy2), SEQ ID NO : 179 (cPEPpizza), SEQ ID NO : 180 (cPEPmrbl), SEQ ID NO : 181 (cPEPtaptap 46), SEQ ID NO : SEQ ID NO : 182 NO : 183 (cPEPga2ox7), SEQ ID NO : 184 (cPEPphyb), SEQ ID NO : 185 (cPEPhagô), SEQ ID NO : 186 (cPEPshr), SEQ ID NO : 187 (cPEPmapkkk3),SEQ ID NO : 188 (cPEPmapkkk5_1), SEQ ID NO : 189 (cPEPmapkkk5_2), SEQ ID NO : 190 (cPEPringl), SEQ ID NO : 191 (cPEProsI), SEQ ID NO : 192 (cPEPjarl), SEQ ID NO : 193 (cPEPcoil), SEQ ID NO : 194 (cPEPabcg34), SEQ ID NO : 195 (cPEPagbl), SEQ ID NO : 196 (cPEPwus), SEQ ID NO : 197 (AhEIN2), SEQ ID NO : 198 (AhBRH), SEQ ID NO : 199 (AhBAKI), SEQ ID NO : 200 (AtEIN2cPEP1), SEQ ID NO : 201 (AtEIN2cPEP2), SEQ ID NO : 202 (AtEIN2cPEP3), SEQ ID NO : 203 (AtEIN2cPEP13), SEQ ID NO : 204 (cPEPein2_1), SEQ ID NO : 205 (cPEPein2_2), SEQ ID NO : 206 (cPEPein2_3), SEQ ID NO : 404 (cPEPhsp101), SEQ ID NO : 406 (cPEPabiô), SEQ ID NO : 407 (cPEPsgrl), SEQ ID NO : 408 (cPEPhsp101), SEQ ID NO : 409 (cPEPmrbl), SEQ ID NO : 410 (cPEPshy2), SEQ ID NO : 411 (cPEPskl), SEQ ID NO : 412 (cPEPrhIO), SEQ ID NO : 413 (cPEpjarl), SEQ ID NO : 414 (cPEPbakl), SEQ ID NO : 415 (cPEPbril), SEQ ID NO : 416 (cPEPwus) et SEQ ID NO : 417 (cPEPein2). En particulier,the invention relates to the method for preparing and determining a cPEP as described above, in which the sequence of said peptide is chosen from the sequences: SEQ ID NO: 162, SEQ ID NO: 163 and SEQ ID NOs: 164 to 174. In particular, the invention relates to the method for preparing and determining a cPEP as described above, in which the sequence of said peptide is the sequence SEQ ID NO: 162. In particular, the invention relates to the method for preparing and determining a cPEP as described above, in which the sequence of said peptide is the sequence: SEQ ID NO: 163. In particular, the invention relates to the method for preparing and determining a cPEP as described above, in which the sequence of said peptide is chosen from the sequences: SEQ ID NOs: 164 to 174.,

[0106] In a second aspect, the subject of the invention above is a cPEP as obtained by implementing the method as described above. According to this same aspect, the subject of the invention is also a cPEP, of 4 to 70 amino acids, in particular of 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment (not naturally translated) of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0107] In one embodiment, the invention relates to cPEP as previously described, said fragment having a size of 3n nucleotides, n being comprised: from 4 to 41; from 5 to 40; from 7 to 20; or from 8 to 15.

[0108] In other words, the invention relates to the cPEP as described above, said cPEP comprising s, 6, 7, 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, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 or 70 amino acids.

[0109] In particular, the invention relates to cPEP as described above, said cPEP comprising from 4 to 41 amino acids. In particular, the invention relates to cPEP as described above, said cPEP comprising from 5 to 40 amino acids. In particular, the invention relates to cPEP as described above, said cPEP comprising from 7 to 20 amino acids. In particular, the invention also relates to cPEP as described above, said cPEP comprising from 8 to 15 amino acids.

[0110] In one embodiment, the invention relates to cPEP as described above, wherein the size of said cPEP is smaller than that of said protein.

[0111] In one embodiment, the invention relates to the cPEP as described above, said fragment being devoid of: the initiator codon AUG coding an initiator methionine; or a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0112] In one embodiment, the invention therefore relates to the cPEP as described above, said fragment comprising an initiator codon AUG encoding an initiator methionine and being devoid of a STOP codon chosen from the codons: UAG, UGA and UAA. The invention also relates to the cPEP as described above, said fragment being devoid of an initiator codon AUG encoding an initiator methionine and comprising a STOP codon chosen from the codons: UAG, UGA and UAA.

[0113] In one embodiment, the invention relates to the cPEP as described above, said fragment being devoid of: the initiator codon AUG coding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and in which said fragment is chosen: either in the same reading frame as the open reading frame coding said protein; or in a reading frame shifted by one or two nucleotides relative to the open reading frame coding said protein.

[0114] In one embodiment, the invention relates to cPEP as described above, wherein the translation of the mRNA fragment is carried out in the same reading frame as the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to cPEP as described above, wherein the translation of the mRNA fragment is carried out in the reading frame determined by the initiation codon of the open reading frame of said protein.

[0115] In one embodiment, the invention relates to cPEP as described above, wherein the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to cPEP as described above, wherein the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention also relates to cPEP as described above, wherein the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In other words, the invention relates to the cPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0116] In one embodiment, the subject of the invention is a cPEP, of 4 to 70 amino acids, in particular of 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence of an mRNA of a protein, said nucleic acid sequence comprising two contiguous parts: a part located within a nucleic acid sequence known to be non-coding ( / .e. not naturally translated, eg 3'IITR or 5'IITR); and a part located within a nucleic acid sequence deemed to be coding ( / .e. naturally translated, eg exon), said fragment having a size of 3n nucleotides, n being from 4 to 70, in particular n being from 4 to 41, and said cPEP being capable of modulating the accumulation of said protein in a plant cell and not being capable of modulating the accumulation of the mRNA coding said protein.

[0117] In one embodiment, the invention relates to cPEP as described above, wherein said cPEP is capable of increasing the accumulation of said protein in said plant cell. In one embodiment, the invention relates to cPEP as described above, wherein said cPEP is capable of decreasing the accumulation of said protein in said plant cell.

[0118] In one embodiment, the invention relates to cPEP as described above, wherein said cPEP is a synthetic peptide.

[0119] In one embodiment, the invention relates to cPEP as described above, wherein said cPEP is an isolated peptide.

[0120] In one embodiment, the invention relates to cPEP as described above, wherein said cPEP is a recombinant peptide.

[0121] In one embodiment, the invention relates to cPEP as described above, said cPEP being a hydrophobic peptide or a hydrophilic peptide.

[0122] In one embodiment, the invention relates to cPEP as described above, wherein said protein is naturally present in said plant cell.

[0123] In one embodiment, the invention relates to cPEP as described above, wherein said protein is not naturally present in said plant cell. In particular, the invention relates to cPEP as described above, wherein said protein is encoded by a transgene artificially introduced into said plant cell. In particular, the invention relates to cPEP as described above, wherein said protein is encoded by a vector artificially introduced into said plant cell.

[0124] In one embodiment, the invention relates to the cPEP as previously described, wherein said plant cell ( / .e. that in which it is desired to modulate the accumulation of a protein) belongs to a plant species selected among: Alopecurus, Hypochondria, Amacus, hypochondria Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis halleri, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (rapeseed), Camelina, Carella capella, Capellas grandi, Capellas captiva papaya, Eutrema salsugineum, Glycine max (soybean), Gossypium raimondii, Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (lottery), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tobacco), Oryza sativa (rice), Pisum sativum (peas), Raphanus sativus, Solanum lycopersicum (tomato), Solanum melongena (aubergine), Solanum tuberosum (apple), Thellungiella halophila, Theobroma cacao, Triticum spp. (blé), Vitis vinifera (vine) and Zea mays (corn). In the original version, the invention concerns the cPEP as previously described, which is a cell of an algae.

[0125] In one embodiment, the invention relates to cPEP as described above, wherein said protein is encoded by a gene selected from: Aae15, Aae16, abcg11, Abdcg34, Acd, Agb1, Als, Anac076, Apg9, Arlbl, Arr1, Arr5, Arr6, At59, Bak1, Bccpl, Bccp2, Bri1, Bzo2h3, Cesaô, Cipk3, Cks1, Cobl8, Coi1, Cpk3, Crk34, Cyp705a18, Cyp71b26, Cyp78a8, Cyp97b3, Dell, Dur3, Ein2, Emb175, Emb2726, Emb9, Epsps, Fnr1, Eve, Ga2ox7, Gapc, Gcn2, Gdi2, Gln2, Gsl3, Hag5, Hda18, Hexol, Hppd, Hsl1, Iaa31, Iqd28, Jac1, Jar1, Kp1, Lrx2, Mapkkk3, Mapkkkô, Mfp2, Mrb1, Nsp1, Pds, Pen3, Phyb, Pif 3, Pizza, Ppoxl, Ppox2, Prp39, PsbA, Pskrl, Rd21, Ringl, Rosi, Rpt4a, Sfr6, Shr, Shy2, Ski, Sps1, Spt, Stn8, Tap46, Toppô, TubB6, TubB8, Ubala, Vim3, Sgr1, Abi5, Hsp101, RhIO and Wus.

[0126] In particular, the invention relates to cPEP as described above, wherein said protein is encoded by a gene selected from the genes: Cpk3, Dell and Nsp1. In particular, the invention relates to cPEP as described above, wherein said protein is encoded by the Cpk3 gene. In particular, the invention relates to cPEP as described above, wherein said protein is encoded by the Dell gene. In particular, the invention relates to cPEP as described above, wherein said protein is encoded by the Nsp1 gene.

[0127] In one embodiment, the invention relates to cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385.

[0128] In particular, the invention relates to the invention relates to cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1). In particular, the invention also relates to cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3).In particular, the invention also relates to cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence selected from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention also relates to cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence selected from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0129] In one embodiment, the invention relates to cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence chosen from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385. The invention relates in particular to cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0130] In particular, the invention relates to cPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to cPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention relates to cPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0131] In another embodiment, the invention relates to cPEP as described above, in which the sequence of said peptide is chosen from the sequences: SEQ ID NOs: 162 to 206, 404 and 406 to 417.

[0132] In particular, the invention relates to cPEP as described above, wherein the sequence of said peptide is selected from the sequences: SEQ ID NO: 162, SEQ ID NO: 163 and SEQ ID NOs: 164 to 174. In particular, the invention relates to cPEP as described above, wherein the sequence of said peptide is the sequence SEQ ID NO: 162. In particular, the invention relates to cPEP as described above, wherein the sequence of said peptide is the sequence: SEQ ID NO: 163. In particular, the invention relates to cPEP as described above, wherein the sequence of said peptide is selected from the sequences: SEQ ID NOs: 164 to 174.

[0133] In one embodiment, the invention relates to cPEP as described above, wherein said protein is involved in at least one plant phenotype selected from: leaf size, shape, area, volume, mass and number; flower size, shape, area, volume, mass and number; stem (or floral stalk) size; root biomass; root number, length and branching level; germination precocity; budding precocity; floral induction (or floral transition) precocity; germination vigor and juvenile phase duration; flowering duration; biotic stress resistance; abiotic stress resistance; and cell number.

[0134] In the invention, a cPEP may be fused or linked to one or more molecules that facilitate the entry of the cPEP into the cell. These molecules include, in particular, penetrating peptides (Numata, K., et al. Library screening of cell-penetrating peptide for BY-2 cells, leaves of Arabidopsis, tobacco, tomato, poplar, and rice callus. Sci Rep 8, 10966 (2018).) and palmitic acid. By "penetrating peptide" (hereinafter CPP), we mean small peptides that penetrate cellular lipid bilayers or destabilize cellular membranes. CPPs can be classified into three groups: cationic, amphipathic, and hydrophobic.In particular: cationic CPPs contain many positively charged amino acids, such as lysine (Lys) and arginine (Arg); amphipathic CPPs are generally composed of an alternating sequence of polar and nonpolar amino acids; and hydrophobic CPPs consist of nonpolar amino acids with relatively low net charges.

[0135] In one embodiment, the invention relates to cPEP as described above, said cPEP being fused to a peptide facilitating its entry into the plant cell. In particular, the invention relates to cPEP as described above, said cPEP being fused to a penetrating peptide.

[0136] In one embodiment, the invention relates to cPEP as described above, said cPEP being fused at the N-terminus or at the C-terminus with said peptide facilitating its entry into the plant cell. In particular, the invention relates to cPEP as described above, said cPEP being fused at the N-terminus or at the C-terminus with said penetrating peptide. In one embodiment, the invention relates to cPEP as described above, said cPEP being fused with: the TAT peptide (SEQ ID NO: 380); penetratin; a polyhistidine peptide (in particular a peptide of at least 4 histidine residues); or a polyarginine peptide (in particular a peptide of 4 arginine residues).

[0137] In one embodiment, the invention relates to cPEP as described above, said cPEP being linked to one or more palmitic acid molecules.

[0138] In one embodiment, the invention relates to cPEP as described above, said cPEP being linked at the N-terminus or at the C-terminus to one or more palmitic acid molecules.

[0139] On this point, it should be noted that the amount of cPEP required to modulate the accumulation of a protein may vary depending on whether or not the cPEP is modified with one of the molecules facilitating its cellular penetration.

[0140] In a third aspect, the above invention relates to a nucleic acid encoding a cPEP as described above. According to this same aspect, the invention also relates to a nucleic acid of 3n nucleotides, which nucleic acid corresponds to a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA.

[0141] In one embodiment, the invention relates to the nucleic acid described above, said fragment being devoid of: the initiator codon AUG coding an initiator methionine; or a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0142] In one embodiment, the invention therefore relates to the nucleic acid as described above, said fragment comprising an initiator codon AUG coding an initiator methionine and being devoid of a STOP codon chosen from the codons: UAG, UGA and UAA. The invention also relates to the nucleic acid as described above, said fragment being devoid of an initiator codon AUG coding an initiator methionine and comprising a STOP codon chosen from the codons: UAG, UGA and UAA.

[0143] In one embodiment, the invention relates to the nucleic acid described above, said fragment being devoid of: the initiator codon AUG coding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0144] In one embodiment, the invention relates to the nucleic acid as described above, wherein the translation of the mRNA fragment is carried out in the same reading frame as the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the nucleic acid as described above, wherein the translation of the mRNA fragment is carried out in the reading frame determined by the initiation codon of the open reading frame of said protein.

[0145] In one embodiment, the invention relates to the nucleic acid as described above, wherein the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the nucleic acid as described above, wherein the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the nucleic acid as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the nucleic acid as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In one embodiment, the invention relates to a nucleic acid of 3n nucleotides, which nucleic acid corresponds to a fragment of a nucleic acid sequence of an mRNA of a protein, said nucleic acid sequence comprising two contiguous parts: a part located within a nucleic acid sequence known to be non-coding ( / .e. not naturally translated, eg 3'UTR or 5'IITR); and a part located within a nucleic acid sequence known to be coding ( / .e. naturally translated, eg exon).

[0146] In particular, the invention relates to the nucleic acid as described above, where n is comprised: from 4 to 70; from 4 to 41; from 5 to 40; from 7 to 20; or from 8 to 15.

[0147] In another aspect, the above invention relates to a composition comprising a cPEP as described above as an active ingredient.

[0148] In one embodiment, the invention relates to a composition comprising a cPEP as an active substance, said cPEP:

[0149] - having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA; and

[0150] - being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0151] In one embodiment, the invention relates to the composition as described above, in which said fragment lacks: the initiator codon AUG coding an initiator methionine; or a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0152] In one embodiment, the invention therefore relates to the composition as described above, in which said fragment comprises an initiator codon AUG encoding an initiator methionine and is devoid of a STOP codon chosen from the codons: UAG, UGA and UAA. The invention also relates to the composition as described above, in which said fragment is devoid of an initiator codon AUG encoding an initiator methionine and comprises a STOP codon chosen from the codons: UAG, UGA and UAA.

[0153] In one embodiment, the invention relates to the composition as described above, in which said fragment lacks: the initiator codon AUG coding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0154] In one embodiment, the invention relates to the composition as described above, in which the translation of the mRNA fragment is carried out in the same reading frame as the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the composition as described above, in which the translation of the mRNA fragment is carried out in the reading frame determined by the initiation codon of the open reading frame of said protein.

[0155] In one embodiment, the invention relates to the composition as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the composition as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the composition as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the composition as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0156] In one embodiment, the invention relates to a composition comprising a cPEP as an active substance, said cPEP:

[0157] - having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said fragment having a size of 3n nucleotides, n being from 4 to 70, in particular n being from 4 to 41, and said nucleic acid sequence comprising two contiguous parts:

[0158] ■ a part located within a nucleic acid sequence known to be non-coding ( / .e. not naturally translated, eg 3'IITR or 5'IITR); and

[0159] ■ a part located within a nucleic acid sequence known to be coding ( / .e. naturally translated, eg exon); and

[0160] - being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0161] In one embodiment, the invention relates to the composition as described above, wherein said cPEP is at a concentration of 10' 9 M to 10' 3 Mr. On this point, it should be noted on the one hand that the composition of the invention does not exist in its natural state and this is all the more true since such a concentration of cPEP cannot exist within a plant cell. In addition and by "concentration of 10' 9 M to 10' 3 M”, we mean that the cPEP concentration can be understood from 10' 9 at 10' 4 M, 10' 8 at 10' 4 M, 10' 9 at 10' 5 M, 10' 8 at 10' 5M, as it can be understood from 5 pM to 500 pM, from 30 pM to 70 pM, or even be 50 pM.

[0162] In particular, the invention relates to the composition as described above, in which said cPEP is at a concentration of 10' 9 at 10' 4 M, 10' 8 at 10' 4 M, 10' 9 at 10' 5 M or 10' 8 at 10' 5 M. In particular, the invention relates to the composition as described above, wherein said cPEP is at a concentration of from 5 pM to 500 pM or from 30 pM to 70 pM. In particular, the invention relates to the composition as described above, wherein said cPEP is at a concentration of 50 pM. In a non-limiting manner, this concentration may also be 10' 9 M, 10' 8 M, 10' 7 M, 10' 6 M, 10' 5 M or IO' 4 Mr.

[0163] In view of the above, it is understood that the invention also relates to the composition comprising a cPEP as an active substance, said cPEP: having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA; being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein; and being in particular at a concentration of from 5 pM to 500 pM or from 30 pM to 70 pM, or being in particular at a concentration of 50 pM.

[0164] It should be noted that by "composition comprising a cPEP" is meant that the composition of the invention comprises at least one cPEP. That is to say that a mixture of cPEPs is conceivable, said cPEPs being able to target the same protein or several proteins depending on the nucleic acid fragment from which they are derived. In this regard, the aforementioned concentrations relate either to the mixture of cPEPs as such, or to each of the cPEPs of said mixture, said cPEPs being able to be at the same concentration or being able to be at different concentrations among those mentioned above.

[0165] In one embodiment, the invention relates to the composition as described above, said composition being a phytopharmaceutical composition, a herbicidal composition or a coating composition, in particular said coating composition further comprising at least one fixing agent.

[0166] In particular, the invention relates to the composition as described above, said composition being a phytopharmaceutical composition. In particular, the invention relates to the composition as described above, said composition being a herbicidal composition. In particular, the invention relates to the composition as described above, said composition being a coating composition. Preferably, the invention relates to the composition as described above, said composition being a coating composition further comprising at least one fixing agent. In one embodiment, the invention relates to the composition as described above, said composition further comprising at least one solvent.Preferably, said solvent is chosen from: acetone, acetonitrile, acetic acid, formic acid, dimethyl adipate, benzyl acetate, bi-butyl carbonate, dimethyl sulfoxide (DMSO), water, dimethyl glutarate, ammonium hydroxide, isobutanol, iso-propanol, diethyl hexyl lactate, light aromatic naphtha solvent, heavy aromatic naphtha solvent, diethyl succinate and mixtures thereof (e.g. mixture [water; acetic acid]; [acetonitrile; acetic acid], [water, acetonitrile; acetic acid], [water; DMSO], [water; acetonitrile] or [water; ammonium hydroxide]).

[0167] The solubility properties of cPEPs are determined in particular by their amino acid composition. Hydrophilic cPEPs can be solubilized and packaged in aqueous solutions, such as water. Hydrophobic cPEPs can be solubilized and packaged in solvents, such as organic solvents.

[0168] For treatment of plants with cPEPs, organic solvents are non-toxic solvents for plants in small quantities, that is to say they have no deleterious effect on the development of the plant. In a non-limiting manner, the organic solvents may be those mentioned above and in particular chosen from acetonitrile and acetic acid.

[0169] As indicated above, cPEPs can also be solubilized and packaged in solvent mixtures, such as, for example, an organic solvent mixture [acetonitrile; acetic acid], a mixture [water; DMSO] in a volume:volume ratio of 99:1 to 1:99, a mixture [water; acetonitrile] in a volume:volume ratio of 99:1 to 1:99, or a mixture [water; ammonium hydroxide] in a volume:volume ratio of 99:1 to 99.9:0.1. cPEPs can also be solubilized in a solution comprising 50% acetonitrile, 10% acetic acid, and 40% water (volume / volume / volume).

[0170] In one embodiment, the invention relates to the composition as described above, said composition further comprising at least one diluent.

[0171] In one embodiment, the invention relates to the composition as described above, said composition further comprising at least one adjuvant.

[0172] In one embodiment, the invention relates to the composition as described above, said composition further comprising at least one fixing agent.

[0173] By "fixing agent" is meant a chemical or natural agent which allows the composition of the invention to be bonded to a plant seed so as to coat said plant seed. It also means a substance making it possible to apply and hold the active substance(s) on the grain. Among the available fixing agents are carboxymethyl cellulose (CMC) and gum arabic. In addition, and in a non-limiting manner, a fixing agent may comprise organic solvents, water, dispersants, emulsifiers, surfactants, wetting agents and colorants.

[0174] In one embodiment, the invention relates to the composition as described above, said composition further comprising at least one plant nutrient. In particular, the invention relates to the composition as described above, said composition further comprising at least one fixing agent and at least one plant nutrient.

[0175] By "plant nutrient" we mean an element assimilated by the plant to enable its development. A plant nutrient may be chosen, without limitation, from: nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, manganese, iron, copper, boron, zinc, molybdenum and mixtures thereof.

[0176] In view of the above, it is understood that another aspect of the invention relates to a coated seed comprising a plant seed, said plant seed being coated with a coating composition as described above.

[0177] The coating can be carried out using processes conventionally used in the food industry and can be obtained using a material capable of disintegrating in a solvent or in the earth, such as a binder or clay.

[0178] According to the invention, the coating can be used to confer particular properties to a seed in combination with a cPEP, such as improved growth or resistance to certain biotic or abiotic stresses.

[0179] In one embodiment, the invention relates to the enrobed seed as described previously, wherein said plant seed has a plant species selected among: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis, Arabidopsis, Arabidopsis, halley, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (rapeseed), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eutrema salsugineum, Gsopium massy, ​​Goxpium mass raimondii, Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (trefoil), Medicago sativa (alfalfa), Medicago truncatula (alfalfa), Nicotiana benthamiana (tobacco), Oryza sativa (rice), Pisum sativum (pea), Raphanus sativus, Solanum lycopersicum (tomato), Solanum melongena (eggplant), Solanum tuberosum (potato), Thellungiella halophila, Theobroma cacao, Triticum spp. (wheat), Vitis vinifera (vine) and Zea mays (corn).

[0180] In one embodiment, the invention relates to the coated seed as described above, said seed being treated by soaking in a composition containing a cPEP. During soaking, the seed is then immersed totally or partially in a composition containing a cPEP.

[0181] In another aspect, the above invention relates to a use of a cPEP as a phytosanitary agent for modulating the accumulation of a protein in a plant cell, said cPEP having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of said protein encoded by said mRNA, said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0182] In one embodiment, the invention relates to the use of a cPEP as described above, in which said fragment lacks: the initiator codon AUG coding an initiator methionine; or a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0183] In one embodiment, the invention therefore relates to the use of a cPEP as described above, in which said fragment comprises an initiator codon AUG encoding an initiator methionine and is devoid of a STOP codon chosen from the codons: UAG, UGA and UAA. The invention also relates to the use of a cPEP as described above, in which said fragment is devoid of an initiator codon AUG encoding an initiator methionine and comprises a STOP codon chosen from the codons: UAG, UGA and UAA.In one embodiment, the invention relates to the use of a cPEP as described above, in which said fragment lacks: the initiator codon AUG coding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0184] In one embodiment, the invention relates to the use of a cPEP as described above, in which the translation of the mRNA fragment is carried out in the same reading frame as the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the use of a cPEP as described above, in which the translation of the mRNA fragment is carried out in the reading frame determined by the initiation codon of the open reading frame of said protein.

[0185] In one embodiment, the invention relates to the use of a cPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the use of a cPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the use of a cPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the use of a cPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0186] In one embodiment, the invention relates to a use of a cPEP as a phytosanitary agent for modulating the accumulation of a protein in a plant cell, said cPEP having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of said protein encoded by said mRNA, said fragment having a size of 3n nucleotides, n being from 4 to 70, in particular n being from 4 to 41, and said nucleic acid sequence comprising two contiguous parts: a part located within a nucleic acid sequence known to be non-coding ( / .e. not naturally translated, eg intron); and a part located within a nucleic acid sequence known to be coding ( / .e. naturally translated, egexon); said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0187] In one embodiment, the invention relates to the use of a cPEP as described above to increase the accumulation of said protein in the plant cell. The presence of the cPEP causes the amount of said protein in the treated plant cell to be greater than that in an untreated plant cell.

[0188] In one embodiment, the invention relates to the use of a cPEP as described above for decreasing (inhibiting) the accumulation of said protein in the plant cell. The presence of the cPEP causes the amount of said protein in the treated plant cell to be lower than that in an untreated plant cell.

[0189] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said cPEP is produced outside of said plant cell before being introduced into said plant cell.

[0190] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said cPEP is a synthetic peptide.

[0191] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said cPEP is an isolated peptide.

[0192] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said cPEP is a recombinant peptide.

[0193] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said cPEP is a hydrophobic peptide or a hydrophilic peptide. In one embodiment, the invention relates to the use of a cPEP as described above, wherein said cPEP is introduced into said plant cell in the form of a nucleic acid encoding said cPEP. In particular, the invention relates to the use of a cPEP as described above, wherein said cPEP is introduced into said plant cell in the form of a nucleic acid encoding said cPEP and comprising the means for expressing it.

[0194] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said protein is naturally present in said plant cell.

[0195] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said protein is not naturally present in said plant cell. In particular, the invention relates to the use of a cPEP as described above, wherein said protein is encoded by a transgene artificially introduced into said plant cell. In particular, the invention relates to the use of a cPEP as described above, wherein said protein is encoded by a vector artificially introduced into said plant cell.

[0196] In one embodiment, the invention relates to the use of a cPEP as described above, wherein the accumulation of said protein is determined via the implementation of a technique chosen from: Western blot, measurement of enzymatic activity, mass spectrometry and translational fusion. In particular, the invention relates to the use of a cPEP as described above, wherein the accumulation of said protein is determined via the implementation of a Western blot.

[0197] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said cPEP has a size of 4 to 41 amino acids, 5 to 40 amino acids, 7 to 20 amino acids or more particularly a size of 8 to 15 amino acids. In particular, said cPEP has a size of 4, 5, 6, 7, 8, 9, 10, 11, 12, 13,

[0198] 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,

[0199] 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63,

[0200] 64, 65, 66, 67, 68, 69 or 70 amino acids.

[0201] In one embodiment, the invention relates to the use of a cPEP as previously described, wherein said plant cell belongs to a plant species selected among: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, tuberidus, Arabidophus, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (rapeseed), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eut. Gossypium raimondii, Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (lotier), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tabac), Oryza sativa (riz), Pisum sativum (pois), Raphanus sativus, Solanum lycopersicum (tomate), Solanum melongena (aubergine), Solanum tuberosum (pomme de terre), Thellungiella halophila, Theobroma cacao, Triticum spp. (blé), Vitis vinifera (vines) and Zea mays (maize).

[0202] In particular, the invention concerns the use of a cPEP as described previously, in which the most common vegetal cells are the cells of another.

[0203] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said protein is encoded by a gene selected from: Aae15, Aae16, abcg11, Abdcg34, Acc1, Agb1, Als, Anac076, Apg9, Aribl, Arr1, Arr5, Arr6, At59, Bak1, Bccpl, Bccp2, Bri1, Bzo2h3, Cesaô, Cipk3, Cks1, Cobl8, Coi1, Cpk3, Crk34, Cyp705a18, Cyp71b26, Cyp78a8, Cyp97b3, Dell, Dur3, Ein2, Emb175, Emb2726, Emb9, Epsps, Fnr1, Eve, Ga2ox7, Gapc, Gcn2, Gdi2, Gln2, Gsl3, Hag5, Hda18, Hexol, Hppd, Hsl1, Iaa31, Iqd28, Jac1, Jar1, Kp1, Lrx2, Mapkkk3, Mapkkko, Mfp2, Mrb1, Nsp1, Pds, Pen3, Phyb, Pif3, Pizza, Ppoxl, Ppox2, Prp39, PsbA, Pskrl, Rd21, Ringl, Rosi, Rpt4a, Sfr6, Shr, Shy2, Ski, Sps1, Spt, Stn8, Tap46, Toppô, TubB6, TubB8, Ubala, Vim3, Sgr1, Abi5, Hsp101, Rh10 and Wus.

[0204] In view of the above, it is understood that in another embodiment, the invention relates to the use of a cPEP as described above, said cPEP having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a non-naturally translated fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of said protein encoded by said mRNA, said non-naturally translated fragment being devoid of the initiator codon AUG encoding an initiator methionine and / or of a STOP codon chosen from the codons: UAG, UGA and UAA, and being chosen either in the same reading frame as the open reading frame encoding said protein, or in a reading frame shifted by one or two nucleotides relative to the open reading frame encoding said protein,and said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein, said protein being encoded by a gene selected from: Aae15, Aae16, abcg11, Abdcg34, Acc1, Agb1, Als, Anac076, Apg9, Arlbl, Arr1, Arr5, Arr6, At59, Bak1, Bccpl, Bccp2, Bri1, Bzo2h3, Cesaô, Cipk3, Cks1, Cobl8, Coi1, Cpk3, Crk34, Cyp705a18, Cyp71b26, Cyp78a8, Cyp97b3, Dell, Dur3, Ein2, Emb175, Emb2726, Emb9, Epsps, Fnr1, Eve, Ga2ox7, Gapc, Gcn2, Gdi2, Gln2, Gsl3, Hag5, Hda18, Hexol, Hppd, Hsl1, Iaa31, Iqd28, Jac1, Jar1, Kp1, Lrx2, Mapkkk3, Mapkkkô, Mfp2, Mrb1, Nsp1, Pds, Pen3, Phyb, Pif 3, Pizza, Ppoxl, Ppox2, Prp39, PsbA, Pskrl, Rd21, Ringl, Rosi, Rpt4a, Sfr6, Shr, Shy2, Ski, Sps1, Spt, Stn8, Tap46, Toppô, TubBô, TubB8, Ubala, Vim3, Sgr1, Abi5, Hsp101, Rh10 and Wus.,

[0205] In one embodiment, the invention relates to the use of a cPEP as described above, in which said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385.

[0206] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0207] In particular, the invention relates to the use of a cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the use of a cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 61 to 79 (Dell).In particular, the invention relates to the use of a cPEP as described above, in which said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0208] In one embodiment, the invention relates to the use of a cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385. In one embodiment, the invention also relates to the use of a cPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0209] In particular, the invention relates to the use of a cPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the use of a cPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention relates to the use of a cPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0210] In another embodiment, the invention relates to the use of a cPEP as described above, wherein said cPEP is selected from the sequences: SEQ ID NOs: 162 to 206, 404 and 406 to 417.

[0211] In particular, the invention relates to the use of a cPEP as described above, wherein said cPEP is selected from the sequences: SEQ ID NO: 162, SEQ ID NO: 163 and SEQ ID NOs: 164 to 174. In particular, the invention relates to the use of a cPEP as described above, wherein said cPEP is of sequence SEQ ID NO: 162. In particular, the invention relates to the use of a cPEP as described above, wherein said cPEP is of sequence: SEQ ID NO: 163. In particular, the invention relates to the use of a cPEP as described above, wherein said cPEP is selected from the sequences: SEQ ID NOs: 164 to 174.

[0212] In another embodiment, the invention relates to the use of a cPEP as described above, wherein said protein is involved in at least one plant phenotype selected from: size, shape, surface area, volume, mass and number of leaves; size, shape, surface area, volume, mass and number of flowers; size of the stem (or floral stalk); root biomass; number, length and branching level of the roots; earliness of germination; earliness of budding; earliness of floral induction (or floral transition); germination vigor and duration of juvenile phase; duration of flowering; resistance to biotic stress; resistance to abiotic stress; and number of cells.

[0213] In another embodiment, the invention relates to the use of a cPEP as described above, to modulate the accumulation of a recombinant protein whose nucleic acid sequence which encodes it corresponds to the fusion of the nucleic acid sequences of two distinct genes.

[0214] In particular, the coding sequence of at least one of the two genes is that of a reporter gene, for example a gene coding for a fluorescent protein (such as GFP) or a protein enabling the plant's resistance to a compound.

[0215] In one embodiment, the invention relates to the use of a cPEP as described above, for modulating the accumulation of a recombinant protein whose nucleic acid sequence which codes it corresponds to the fusion: of a nucleic acid sequence known to be non-coding of a first gene; and of a nucleic acid sequence coding for a second gene, the sequence of said cPEP corresponding to the translation via the genetic code of a fragment of the nucleic acid sequence known to be non-coding of the first gene.

[0216] In another aspect, the above invention relates to a method for modulating the accumulation of a protein in a plant cell comprising a step of introducing: a cPEP; or a nucleic acid encoding said cPEP and the means for expressing it, into said plant cell, the introduction of said cPEP resulting in a modulation of the amount of said protein in said plant cell, said cPEP having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of said protein encoded by said mRNA, said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0217] In one embodiment, the invention relates to the method as described above, in which said fragment is devoid of: the initiator codon AUG coding an initiator methionine; or a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment is chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0218] In one embodiment, the invention therefore relates to the method as described above, in which said fragment comprises an initiator codon AUG encoding an initiator methionine and is devoid of a STOP codon chosen from the codons: UAG, UGA and UAA. The invention also relates to the method as described above, in which said fragment is devoid of an initiator codon AUG encoding an initiator methionine and comprises a STOP codon chosen from the codons: UAG, UGA and UAA.

[0219] In one embodiment, the invention relates to the method as described above, in which said fragment is devoid of: the initiator codon AUG coding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment is chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0220] In one embodiment, the invention relates to the method as described above, wherein the translation of the mRNA fragment is carried out in the same reading frame as the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the method as described above, wherein the translation of the mRNA fragment is carried out in the reading frame determined by the initiation codon of the open reading frame of said protein.

[0221] In one embodiment, the invention relates to the method as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the method as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the method as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the method as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0222] In one embodiment, the invention relates to a method of modulating the accumulation of a protein in a plant cell comprising a step of introducing: a cPEP;or a nucleic acid encoding said cPEP and the means for expressing it, in said plant cell, the introduction of said cPEP resulting in a modulation of the quantity of said protein in said plant cell, said cPEP having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of said protein encoded by said mRNA, said fragment having a size of 3n nucleotides, n being from 4 to 70, in particular n being from 4 to 41, and said nucleic acid sequence comprising two contiguous parts: a part located within a nucleic acid sequence known to be non-coding ( / .e. not naturally translated, eg 3'IITR or 5'IITR) ;and a portion located within a nucleic acid sequence deemed to be coding ( / .e. naturally translated, eg exon); said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA coding said protein.;

[0223] In one embodiment, the invention relates to the method as described above, said method making it possible to: promote the development of a plant; or slow down or prevent the development of a plant.

[0224] In particular, the invention relates to the method as described above, said method making it possible to promote the development of a plant. In particular, the invention relates to the method as described above, said method making it possible to slow down or prevent the development of a plant.

[0225] In one embodiment, the invention relates to the method as described above for increasing the accumulation of said protein in the plant cell. The presence of cPEP causes the amount of said protein in the treated plant cell to be greater than that in an untreated plant cell.

[0226] In one embodiment, the invention relates to the method as described above for decreasing (inhibiting) the accumulation of said protein in the plant cell. The presence of cPEP causes the amount of said protein in the treated plant cell to be lower than that in an untreated plant cell.

[0227] In one embodiment, the invention relates to the method as described above, wherein said cPEP is produced outside of said plant cell before being introduced into said plant cell.

[0228] In one embodiment, the invention relates to the method as described above, wherein said cPEP is a synthetic peptide.

[0229] In one embodiment, the invention relates to the method as described above, wherein said cPEP is an isolated peptide.

[0230] In one embodiment, the invention relates to the method as described above, wherein said cPEP is a recombinant peptide.

[0231] In one embodiment, the invention relates to the method as described above, wherein said cPEP is a hydrophobic peptide or a hydrophilic peptide.

[0232] In one embodiment, the invention relates to the method as described above, wherein said cPEP is introduced into said plant cell in the form of a nucleic acid encoding said cPEP. In particular, the invention relates to the method as described above, wherein said cPEP is introduced into said plant cell in the form of a nucleic acid encoding said cPEP and comprising the means for expressing it. In one embodiment, the invention relates to the method as described above, wherein said protein is naturally present in said plant cell.

[0233] In one embodiment, the invention relates to the method as described above, wherein said protein is not naturally present in said plant cell. In particular, the invention relates to the method as described above, wherein said protein is encoded by a transgene artificially introduced into said plant cell. In particular, the invention relates to the method as described above, wherein said protein is encoded by a vector artificially introduced into said plant cell.

[0234] In one embodiment, the invention relates to the method as described above, in which the accumulation of said protein is determined via the implementation of a technique chosen from: Western blot, measurement of enzymatic activity, mass spectrometry and translational fusion. In particular, the invention relates to the method as described above, in which the accumulation of said protein is determined via the implementation of a Western blot.

[0235] In one embodiment, the invention relates to the method as described above, wherein said cPEP has a size of 4 to 41 amino acids, 5 to 40 amino acids, 7 to 20 amino acids or more particularly a size of 8 to 15 amino acids. In particular, said cPEP has a size of 4, 5, 6, 7, 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, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 or 70 amino acids.

[0236] In one embodiment, the invention relates to the procedure as previously described, wherein said plant cell or said plant belongs to a plant species selected from: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmericula, Amaranthus tuberus, Arabidhus Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (rapeseed), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eut. Gossypium raimondii, Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (lotier), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tabac), Oryza sativa (riz), Pisum sativum (pois), Raphanus sativus, Solanum lycopersicum (tomate), Solanum melongena (aubergine), Solanum tuberosum (pomme de terre), Thellungiella halophila, Theobroma cacao, Triticum spp. (blé), Vitis vinifera (vines) and Zea mays (maize).

[0237] In particular, the invention concerns the procedure described above, in which the most vegetal cells are the cells of another.

[0238] In one embodiment, the invention relates to the method as described above, wherein said protein is encoded by a gene selected from: Aae15, Aae16, abcg11, Abdcg34, Acc1, Agb1, Als, Anac076, Apg9, Arlbl, Arr1, Arr5, Arrô, At59, Bak1, Bccpl, Bccp2, Bri1, Bzo2h3, Cesaô, Cipk3, Cks1, Cobl8, Coi1, Cpk3, Crk34, Cyp705a18, Cyp71b26, Cyp78a8, Cyp97b3, Dell, Dur3, Ein2, Emb175, Emb2726, Emb9, Epsps, Fnr1, Eve, Ga2ox7, Gapc, Gcn2, Gdi2, Gln2, Gsl3, Hag5, Hda18, Hexol, Hppd, Hsl1, Iaa31, Iqd28, Jac1, Jar1, Kp1, Lrx2, Mapkkk3, Mapkkkô, Mfp2, Mrb1, Nsp1, Pds, Pen3, Phyb, Pif 3, Pizza, Ppoxl, Ppox2, Prp39, PsbA, Pskrl, Rd21, Ringl, Rosi, Rpt4a, Sfr6, Shr, Shy2, Ski, Sps1, Spt, Stn8, Tap46, Toppô, TubB6, TubB8, Ubala, Vim3, Sgr1, Abi5, Hsp101, RhIO and Wus.

[0239] In view of the above, it is understood that in another embodiment, the invention relates to the method as described above comprising a step of introducing: a cPEP; or a nucleic acid encoding said cPEP and the means for expressing it, into said plant cell, the introduction of said cPEP resulting in a modulation of the quantity of said protein in said plant cell, said cPEP having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a non-naturally translated fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of said protein encoded by said mRNA, said non-naturally translated fragment being devoid of the initiator codon AUG encoding an initiator methionine and / or of a STOP codon chosen from the codons: UAG, UGA and UAA,and being selected either in the same reading frame as the open reading frame encoding said protein, or in a reading frame shifted by one or two nucleotides relative to the open reading frame encoding said protein, and said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein, said protein being encoded by a gene selected from: Aae15, Aae16, abcg11, Abdcg34, Acc1, Agb1, Als, Anac076, Apg9, Arlbl, Arr1, Arr5, Arrô, At59, Bak1, Bccpl, Bccp2, Bri1, Bzo2h3, Cesaô, Cipk3, Cks1, Cobl8, Coi1, Cpk3, Crk34, Cyp705a18, Cyp71b26, Cyp78a8, Cyp97b3, Del 1, Dur3, Ein2, Emb175, Emb2726, Emb9, Epsps, Fnr1, Eve, Ga2ox7, Gape, Gcn2, Gdi2, Gln2, Gsl3, Hag5, Hda18, Hexol, Hppd, Hsl1, Iaa31, Iqd28, Jac1, Jar1, Kp1, Lrx2, Mapkkk3, Mapkkkô, Mfp2, Mrb1, Nsp1, Pds, Pen3, Phyb, Pif3, Pizza, Ppoxl, Ppox2, Prp39, PsbA, Pskrl, Rd21, Ringl, Rosi, Rpt4a, Sfr6, Shr, Shy2, Ski, Sps1,Spt, Stn8, Tap46, Topp6, TubB6, TubB8, Ubala, Vim3, Sgr1, Abi5, Hsp101, Rh10 and Wus.

[0240] In one embodiment, the invention relates to the method as described above, in which said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385.

[0241] In one embodiment, the invention relates to the method as described above, wherein said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0242] In particular, the invention relates to the method as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the method as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention relates to the method as described above, in which said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0243] In one embodiment, the invention relates to the method as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385. In one embodiment, the invention also relates to the method as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1). In particular, the invention relates to the method as described above, wherein said protein is encoded by a gene comprising a selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the method as described above, in which said protein is encoded by a gene comprising one chosen from the sequences: SEQ ID NOs: 61 to 79 (Dell).In particular, the invention relates to the method as described above, in which said protein is encoded by a gene comprising one chosen from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0244] In another embodiment, the invention relates to the method as described above, wherein said cPEP is selected from the sequences: SEQ ID NOs: 162 to 206, 404 and 406 to 417.

[0245] In particular, the invention relates to the method as described above, wherein said cPEP is selected from the sequences: SEQ ID NO: 162, SEQ ID NO: 163 and SEQ ID NOs: 164 to 174. In particular, the invention relates to the method as described above, wherein said cPEP is of sequence SEQ ID NO: 162. In particular, the invention relates to the method as described above, wherein said cPEP is of sequence: SEQ ID NO: 163. In particular, the invention relates to the use of a cPEP as described above, wherein said cPEP is selected from the sequences: SEQ ID NOs: 164 to 174.

[0246] In another embodiment, the invention relates to the method as described above, wherein said protein is involved in at least one plant phenotype selected from: leaf size, shape, area, volume, mass and number; flower size, shape, area, volume, mass and number; stem (or floral stalk) size; root biomass; root number, length and branching level; germination precocity; budding precocity; floral induction (or floral transition) precocity; germination vigor and juvenile phase duration; flowering duration; resistance to biotic stress; resistance to abiotic stress; and cell number. In one embodiment, the invention relates to the method as described above, wherein the introduction of said cPEP results in bolting precocity in said plant.

[0247] In one embodiment, the invention relates to the method as described above, wherein the introduction of said cPEP results in early flowering in said plant.

[0248] In one embodiment, the invention relates to the method as described above, wherein the introduction of said cPEP results in an increase in stem size in said plant.

[0249] In one embodiment, the invention relates to the method as described above, wherein the introduction of said cPEP results in earliness of stem growth in said plant.

[0250] The inventors have in fact unexpectedly observed that it is possible to directly apply a cPEP to the plant, e.g. via the use of the composition of the invention (see above) comprising a cPEP, to modulate the accumulation of a target protein in the plant, which indicates that the cPEP is taken up by the plant.

[0251] Therefore, in one embodiment, the invention relates to the method as described above, in which said cPEP is introduced into said plant: by watering, by spraying or by adding a fertilizer, a potting soil, a growing substrate or a support in contact with the plant, said cPEP being in particular administered to the plant in the form of a composition comprising 10' 9 M to IO' 4 M of said cPEP; by watering, by soaking, by spraying or by adding a fertilizer, a potting soil, a growing substrate or a support in contact with the plant, said cPEP being in particular administered to a seed or a seed in the form of a composition comprising 10' 9 M to 10' 4 M of said cPEP; or by means of a nucleic acid encoding said cPEP and comprising the means for expressing said cPEP, said nucleic acid being artificially introduced into the plant.

[0252] In one embodiment, the invention relates to the method as defined above, wherein said cPEP is artificially introduced externally into the plant, preferably by watering, spraying or by adding a fertilizer, potting soil, growing medium or inert support. In one embodiment, the invention relates to the method as defined above, wherein said cPEP is introduced by watering.

[0253] In one embodiment, the invention relates to the method as defined above, in which said cPEP is introduced by spraying.

[0254] In one embodiment, the invention relates to the method as defined above, in which said cPEP is introduced by the addition of a fertilizer.

[0255] In one embodiment, the invention relates to the method as defined above, in which the plant is treated with a composition comprising 10'9 M to 10' 4 M of said cPEP, or including in particular 10' 9 M, 10' 8 M, 10' 7 M, 10' 6 M, 10' 5 M or 10' 4 M of said cPEP. Preferably, the compositions have a concentration of 10' 8 M to 10' 5 M for application by watering or spraying on the plant.

[0256] In a complementary manner, more or less concentrated compositions can be considered for treating the plant with cPEP. For example, and in a non-limiting manner, more concentrated compositions comprising 10' 1 M to 10' 3 M, or including in particular 10' 2 M of cPEP, can be used in the case where the artificially introduced cPEP externally is administered to the plant by spreading.

[0257] In another aspect, the above invention relates to a modified plant containing a cPEP, which "modified plant" corresponds to a plant into which a cPEP has been artificially introduced, in particular by watering, by spraying or via a fertilizer.

[0258] In one embodiment, the invention relates to the modified plant comprising an exogenously introduced cPEP, said cPEP having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0259] In one embodiment, the invention relates to the modified plant as described above, in which said fragment lacks: the initiator codon AUG coding an initiator methionine; or a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0260] In one embodiment, the invention therefore relates to the modified plant as described above, in which said fragment comprises an initiator codon AUG coding an initiator methionine and is devoid of a STOP codon chosen from the codons: UAG, UGA and UAA. The invention also relates to the modified plant as described above, in which said fragment is devoid of an initiator codon AUG coding an initiator methionine and comprises a STOP codon chosen from the codons: UAG, UGA and UAA.

[0261] In one embodiment, the invention relates to the modified plant as described above, in which said fragment lacks: the initiator codon AUG coding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0262] In one embodiment, the invention relates to the modified plant as described above, in which the translation of the mRNA fragment is carried out in the same reading frame as the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the modified plant as described above, in which the translation of the mRNA fragment is carried out in the reading frame determined by the initiation codon of the open reading frame of said protein.

[0263] In one embodiment, the invention relates to the modified plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the modified plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the modified plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the modified plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0264] In one embodiment, the invention relates to a modified plant comprising an exogenously introduced cPEP, said cPEP having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said fragment having a size of 3n nucleotides, n being from 4 to 70, in particular n being from 4 to 41, and said nucleic acid sequence comprising two contiguous parts: a part located within a nucleic acid sequence known to be non-coding ( / .e. not naturally translated, eg 3'IITR or 5'IITR); and a part located within a nucleic acid sequence known to be coding ( / .e. naturally translated, egexon); said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0265] In a way of realization, the invention concerns the modified plant described previously, with plants belonging to a selected plant species: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis halleri, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rape), Brassica oleracea, Brassica rapa (rape), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eutrema salsugineum, Glycine max (soya), Gossypium raimondii, Gossypium spp. (coton), Hordeum vulgare (orge), Lollium spp., Lotus japonicus (lotier), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tabac), Oryza sativa (riz), Pisum sativum (pois), Raphanus sativus, Solanum lycopersicum (tomate), Solanum melongena (aubergine), Solanum tuberosum (pomme de terre), Thellungiella halophila, Theobroma cacao, Triticum spp.(wheat), Vitis vinifera (vine) and Zea mays (corn). In another aspect, the above invention relates to a transgenic plant comprising a nucleic acid encoding a cPEP and the means for expressing it, said cPEP having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0266] In one embodiment, the invention relates to the transgenic plant as described above, in which said fragment lacks: the initiator codon AUG coding an initiator methionine; or a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0267] In one embodiment, the invention therefore relates to the transgenic plant as described above, in which said fragment comprises an initiator codon AUG coding an initiator methionine and is devoid of a STOP codon chosen from the codons: UAG, UGA and UAA. The invention also relates to the transgenic plant as described above, in which said fragment is devoid of an initiator codon AUG coding an initiator methionine and comprises a STOP codon chosen from the codons: UAG, UGA and UAA.

[0268] In one embodiment, the invention relates to the transgenic plant as described above, in which said fragment lacks: the initiator codon AUG coding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen: either in the same open reading frame as that coding said protein; or in an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0269] In one embodiment, the invention relates to the transgenic plant as described above, in which the translation of the mRNA fragment is carried out in the same reading frame as the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the transgenic plant as described above, in which the translation of the mRNA fragment is carried out in the reading frame determined by the initiation codon of the open reading frame of said protein.

[0270] In one embodiment, the invention relates to the transgenic plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the transgenic plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the transgenic plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the transgenic plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0271] In one embodiment, the invention relates to a transgenic plant comprising an exogenously introduced cPEP, said cPEP having a size of 4 to 70 amino acids, in particular 4 to 70 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said fragment having a size of 3n nucleotides, n being from 4 to 70, in particular n being from 4 to 41, and said nucleic acid sequence comprising two contiguous parts: a part located within a nucleic acid sequence known to be non-coding ( / .e. not naturally translated, eg 3'IITR or 5'IITR); and a part located within a nucleic acid sequence known to be coding ( / .e. naturally translated, egexon); said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0272] In one embodiment, the invention relates to the transgenic plant as defined above, in which the sequence coding for said cPEP is shorter than the sequence of the mRNA coding for said protein.

[0273] In one embodiment, the invention relates to the transgenic plant as previously described, said plant belonging to a plant species selected among: Alopecurus myosuroides, Amaranthus hypochondriacus , Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis, Arabidopsis halleri, Arabidopsis, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (rapeseed), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eutrema salsugineum, Glyxy, Gondis, Raimosium, Raimox Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (trefoil), Medicago sativa (alfalfa), Medicago truncatula (alfalfa), Nicotiana benthamiana (tobacco), Oryza sativa (rice), Pisum sativum (pea), Raphanus sativus, Solanum lycopersicum (tomato), Solanum melongena (eggplant), Solanum tuberosum (potato), Thellungiella halophila, Theobroma cacao, Triticum spp. (wheat), Vitis vinifera (vine) and Zea mays (corn).

[0274] In one embodiment, the invention relates to the transgenic plant as described above, wherein the expression of said cPEP is placed under the control of a strong promoter, preferably a constitutive strong promoter such as the 35S promoter.

[0275] In any respect, it should be noted that the different aspects of invention No. 1, as well as the different embodiments thereof, are interdependent. The latter can therefore be combined with each other to obtain preferred aspects and / or embodiments of invention No. 1 not explicitly described. This is also valid for all the definitions provided in the present description, which applies to all aspects of invention No. 1 and its embodiments. Considering the second invention (altPEP), a first aspect thereof relates to a method for preparing and determining an altPEP, said altPEP: having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids; being capable of modulating the accumulation of a protein in a plant cell; and not being capable of modulating the accumulation of the mRNA encoding said protein, said method comprising: a.a step of determining the nucleic acid sequence of the messenger RNA (mRNA) encoding said protein; b. a step of determining within this mRNA the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame encoding said protein; c. a step of determining within this nucleic acid sequence naturally translated in said plant cell a naturally translated fragment thereof, said fragment having a size of 3n nucleotides capable of being translated via the genetic code into a peptide, n being from 4 to 70, in particular n being from 4 to 41, and said fragment having a size smaller than that of the nucleic acid sequence naturally translated in said plant cell; d. a step of producing said peptide; and e. a comparison step:.

[0276] - between the accumulation of said protein in a plant cell in the presence of said peptide and the accumulation of said protein in a plant cell of the same type in the absence of said peptide; and / or

[0277] - between the phenotype of a plant in the presence of said peptide and the phenotype of a plant of the same type in the absence of said peptide, in which:

[0278] - a difference in the amount of said protein in the presence of said peptide compared to the amount of said protein in the absence of said peptide; and / or

[0279] - a difference in the phenotype in the presence of said peptide compared to the phenotype in the absence of said peptide, indicates that said peptide is an altPEP capable of modulating the accumulation of said protein in a plant cell. The present invention is based on the unexpected observation made by the Inventors that it is possible to specifically modulate the accumulation of a protein using a particular naturally produced peptide, the sequence of which corresponds to the translation of a fragment of the messenger RNA (mRNA) coding for said protein, said fragment being chosen from the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame coding for said protein.

[0280] In the invention, the term “altPEP” (alternative peptide) designates a peptide capable of specifically modulating the accumulation of a protein once introduced into a plant cell.

[0281] According to the invention, an altPEP is naturally present in a plant cell. This means that the plant cell contains the information of the altPEP and the means to enable its expression (e.g. START codon and STOP codon).

[0282] An altPEP may therefore be present in a plant cell and the quantity of it can be modified by artificially adding it, in the form of a peptide or in the form of a nucleic acid encoding said peptide, into the plant cell.

[0283] The specificity of altPEP for a target protein (or a target gene) is determined by its amino acid sequence. Indeed, the sequence of an altPEP corresponds to the translation of a fragment of the mRNA coding for said protein, said fragment being chosen from the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame coding for said protein.

[0284] The peptide sequence of an altPEP can therefore be determined from a fragment of the mRNA encoding said protein.

[0285] In the invention, the fragment of the mRNA used to determine the sequence of the altPEP can be chosen from the two other reading frames than that coding the protein whose accumulation is to be modulated existing on the mRNA sequence. In other words, a fragment can be selected from the reading frames +2 or +3. On this point, it is possible that the other two reading frames (+2 and +3) contain the information of an altPEP as it is possible that only one of the two reading frames (+2 or +3) contains the information of an altPEP.

[0286] In the invention, the term "reading frame" designates the grouping of nucleotides constituting a nucleic acid sequence into consecutive triplets (or codons), which follow one another without interruption or overlap. Generally, altPEPs have a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, in particular a size of 5 to 40 amino acids, 7 to 20 amino acids or more particularly a size of 8 to 15 amino acids. Consequently, the sequence of an altPEP corresponds to the translation of a fragment of 4 to 41 nucleotide triplets, in particular a fragment of 5 to 40 nucleotide triplets, 7 to 20 nucleotide triplets or more particularly a fragment of 8 to 15 nucleotide triplets.

[0287] In other words, the sequence of an altPEP corresponds to the translation into amino acids of a fragment of “3n” nucleotides of the mRNA of the target protein, n being from 4 to 70, in particular n being from 4 to 41, in particular from 5 to 40, from 7 to 20 or more particularly from 8 to 15.

[0288] For example, if n is 5, the altPEP is 5 amino acids long and corresponds to the translation of a fragment of 15 (= 3 x 5) nucleotides. For example, if n is 40, the altPEP is 40 amino acids long and corresponds to the translation of a fragment of 120 (= 3 x 40) nucleotides. For example, if n is 70, the altPEP is 70 amino acids long and corresponds to the translation of a fragment of 210 (= 3 x 70) nucleotides. Etc.

[0289] AltPEPs are sized 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22,

[0290] 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,

[0291] 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 or 70 amino acids, and correspond respectively to the translation of fragments of 12, 15, 18, 21, 24,

[0292] 27, 30, 33, 36, 39, 42, 45, 48, 51, 54, 57, 60, 63, 66, 69, 72, 75, 78, 81, 84, 87, 90, 93, 96, 99,

[0293] 102, 105, 108, 111, 114, 117, 123, 126, 129, 132, 135, 138, 141, 144, 147, 150, 153, 156, 159, 162, 165, 168, 171, 174, 177, 180, 183, 186, 189, 192, 195, 198, 201, 204, 207 or 210 nucleotides.

[0294] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein said fragment has a size of 3n nucleotides, n being comprised: from 4 to 41; from 5 to 40; from 7 to 20; or from 8 to 15.

[0295] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein said peptide has a size selected from: 4, 5, 6, 7, 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, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 and 70 amino acids.

[0296] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein said altPEP has a size smaller than that of said protein (i.e. that whose accumulation altPEP modulates).

[0297] As mentioned above, altPEPs have the ability to specifically modulate the accumulation of a protein without impacting the accumulation of its corresponding mRNA. In other words, adding an altPEP to a plant cell does not change the amount of mRNA used to express the protein it regulates, but only the amount of the protein itself.

[0298] According to the invention, the term "protein" designates an amino acid sequence whose information is encoded by a gene present in the genome of a plant cell. By "gene" is therefore meant, in particular, the nucleic acid sequence necessary for the synthesis of said protein. Also, a gene comprises more than the nucleotides encoding the amino acid sequence of the protein. For example, a gene includes the DNA sequences necessary for the synthesis of a pre-messenger (pre-mRNA), which is then matured by the cellular machinery into a messenger RNA (mRNA). The latter can then be translated, via the ribosomes, into a protein.

[0299] From the above, it is understood that pre-messenger RNA (pre-mRNA) has not undergone splicing and is likely to contain introns, while mature messenger RNA (mRNA) may have undergone splicing and contains only exons.

[0300] To prepare an altPEP capable of modulating the accumulation of a protein, it is necessary to translate a fragment of the mRNA coding for said protein, said fragment being chosen from the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame coding for said protein, which does not include either the 5'-UTR region or the 3'-UTR region of the mRNA.

[0301] In the invention, the "modulation" of the accumulation of a protein means either an increase in the accumulation of said protein ( / .e. an increase in the amount of protein in the plant cell), or a decrease in the accumulation of said protein ( / .e. a decrease in the amount of protein in the plant cell). In other words, an embodiment of the invention relates to the method for preparing and determining an altPEP as described above, in which said modulation of the accumulation of said protein induced by said altPEP is: a decrease in the accumulation of said protein; or an increase in the accumulation of said protein.

[0302] The increase and decrease in the accumulation of said protein can be measured and monitored using methods well known to those skilled in the art, such as coupling the protein to a marker via the use of particular expression cassettes, or a Western blot.

[0303] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein in step e., the amount of protein in the presence of said peptide is greater than the amount of protein in the absence of said peptide. In other words, in the presence of an altPEP promoting increased accumulation of the protein, the translation of the corresponding mRNA is increased, which leads to greater production of the protein without the amount of said mRNA being modified.

[0304] In another embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein in step e., the amount of protein in the presence of said peptide is less than the amount of protein in the absence of said peptide. In other words, in the presence of an altPEP promoting the reduction of the accumulation of the protein, the translation of the corresponding mRNA is reduced (inhibited), which leads to a lower production of the protein without the amount of said mRNA being modified.

[0305] In the invention, the fragment of the mRNA encoding said altPEP is located within the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame encoding said protein, and said fragment as such can also be naturally translated in said plant cell. This is the case regardless of the reading frame used (e.g. +2 and / or +3). The existence of an altPEP within said plant cell is therefore natural and originates either from the cellular machinery or from human action. For this, it is possible either to artificially introduce said altPEP as such, or to introduce an expression cassette comprising the nucleic acid sequence encoding said altPEP and the means for expressing it in said plant cell.

[0306] In the invention, the nucleic acid sequence naturally translated in said plant cell, which comprises a fragment carrying the information of an altPEP, is a region of the mRNA referred to as "coding", that is to say that it corresponds to a region of the mRNA which codes all or part of the functional protein. This sequence therefore corresponds to the main open reading frame ( / .e. the +1), which codes the protein whose accumulation is to be modulated.

[0307] In the invention, the terms "open reading frame" and "ORF" (open reading frame) are equivalent, and can be used interchangeably. They correspond to a sequence of nucleotides (nucleic acids) in a DNA or RNA molecule that can potentially encode a peptide or a protein: said open reading frame begins with a START codon (the START codon generally encoding a methionine), followed by a series of codons (each codon encoding an amino acid), and ends with a STOP codon (the STOP codon not being translated).

[0308] The coding region of mRNA therefore corresponds to the genetic sequence delimited by the START codon or initiation codon (most often coding for a methionine) at the 5' end and by the STOP codon at the 3' end. The coding region of mRNA therefore does not include intronic sequences that may be present in the sequence of a gene or pre-messenger RNA (pre-mRNA), nor the 5'UTR and 3'UTR regions, because these are not translated and therefore do not code for part of the functional protein of the gene.

[0309] In the invention, the sequence of an altPEP is determined by carrying out a translation of a fragment of the mRNA of the protein whose accumulation is to be modulated, said fragment being chosen from the (coding) nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame coding said protein. Also, the same nucleic acid sequence naturally translated in said plant cell can give different altPEPs depending on the fragment of the mRNA chosen. Furthermore, this same mRNA fragment can also give different altPEPs depending on the reading frame used to translate it, / .e. depending on the grouping of the nucleotides of the sequence into consecutive triplets. Indeed and as previously mentioned, a translation can be carried out in two different reading frames (+2 and / or +3) thus leading to potentially two different altPEPs.

[0310] According to the invention, the reading frame “+1” corresponds to the reading frame determined by the initiation codon of the protein, / .e. the START codon of the open reading frame used naturally for the translation of the mRNA.

[0311] The “+2” and “+3” reading frames correspond to reading frames that are not or are only slightly used naturally for the translation of mRNA. According to the invention, the “+2” reading frame corresponds to the reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame used naturally for the translation of mRNA and the protein it encodes. According to the invention, the “+3” reading frame corresponds to the reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame used naturally for the translation of mRNA and the protein it encodes.

[0312] Generally, in the case of an mRNA fragment corresponding to a coding region and translated according to the +2 or +3 reading frame, the altPEPs obtained have a sequence different from that of a fragment of the amino acid sequence of the protein naturally encoded by said mRNA.

[0313] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein said fragment comprises: an initiator codon encoding an initiator methionine; and a STOP codon selected from the codons: UAG, UGA and UAA, and wherein said fragment is selected from a reading frame shifted by one or two nucleotides relative to the open reading frame encoding said protein.

[0314] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the method for preparing and determining an altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the method for preparing and determining an altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the method for preparing and determining an altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein said altPEP is a hydrophobic peptide or a hydrophilic peptide. In particular, the invention relates to the method for preparing and determining an altPEP as described above, wherein said altPEP is a hydrophobic peptide. By "hydrophobic peptide" is meant a peptide whose amino acid sequence comprises more than 50% hydrophobic amino acids. By "more than 50%" is meant that the amino acid sequence comprises more than 55%, more than 60%, more than 65%, more than 70%, more than 75% or more than 80% hydrophobic amino acids. By "more than 50%" is also meant that the amino acid sequence comprises at least 51%, at least 56%, at least 61%, at least 66%, at least 71%, at least 76% or at least 81% of hydrophobic amino acids.By "hydrophobic amino acids" is meant amino acids chosen from: alanine (Ala / A), isoleucine (Ile / I), leucine (Leu / L), methionine (Met / M), phenylalanine (Phe / F), tryptophan (Trp / W), tyrosine (Tyr / Y) and valine (Val / V).

[0315] In particular, the invention also relates to the method for preparing and determining an altPEP as described above, wherein said altPEP is a hydrophilic peptide. By "hydrophilic peptide" is meant a peptide whose amino acid sequence comprises more than 50% hydrophilic amino acids. By "more than 50%" is meant that the amino acid sequence comprises more than 55%, more than 60%, more than 65%, more than 70%, more than 75% or more than 80% hydrophilic amino acids. By "more than 50%" is also meant that the amino acid sequence comprises at least 51%, at least 56%, at least 61%, at least 66%, at least 71%, at least 76% or at least 81% hydrophilic amino acids.By "hydrophilic amino acids" is meant amino acids selected from: aspartic acid (Asp / D), glutamic acid (Glu / E), arginine (Arg / R), asparagine (Asn / N), glutamine (Gin / Q), histidine (His IH), lysine (Lys / K), serine (Ser / S) and threonine (Thr / T).

[0316] According to the invention, an altPEP can be produced by any type of means accessible to those skilled in the art.

[0317] In a non-limiting manner, an altPEP can be produced both synthetically and by recombinant expression in homologous or heterologous systems. The altPEP thus produced can then be introduced into a cell to modulate the accumulation of a target protein. In a non-limiting manner, it is also possible to produce an altPEP directly in the plant cell containing the target protein, by artificially introducing into it a nucleic acid (such as an expression vector) encoding said altPEP.

[0318] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein, in step d., the production of said peptide is carried out by peptide synthesis or by recombinant expression.

[0319] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein, in step d., the production of said peptide is carried out using a nucleic acid encoding said peptide introduced into a cell.

[0320] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein, in step e., the production of said peptide is carried out using a nucleic acid encoding said peptide introduced into said plant cell or into said plant.

[0321] In one embodiment, the invention relates to a method for preparing and determining an altPEP as described above, wherein, in step e., said peptide is brought into contact with said plant cell or in said plant.

[0322] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein, in step e., said peptide is present in said plant cell or in said plant following the expression of a nucleic acid encoding said peptide in said plant cell or in said plant.

[0323] In view of the above, it is understood that another embodiment of the invention relates to the method for preparing and determining an altPEP as described above, in which, in step e., the presence of said peptide in said plant cell or in said plant results:

[0324] - the introduction of a nucleic acid sequence encoding said peptide and comprising the means for expressing it; or

[0325] - the introduction of an amino acid sequence corresponding to said peptide.

[0326] An altPEP can be used to modulate the accumulation of a protein that is naturally occurring (i.e., endogenous) or not (i.e., exogenous) in said plant cell or plant. A "protein naturally occurring in a plant cell or plant" means an endogenous protein encoded by a gene present in the genome of the plant cell or plant without the need for direct or indirect human intervention.

[0327] A “protein that is not naturally present in a plant cell or in a plant” corresponds to an exogenous protein encoded by a nucleic acid sequence present in the genome of the plant cell or of the plant which required the intervention of a human being and the use of means known to those skilled in the art. Such a nucleic acid sequence may come from the same species of plant or from another species of plant.

[0328] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is of endogenous origin in said plant cells or said plants used in step e.

[0329] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, in which said protein is of exogenous origin in said plant cells or said plants used in step e., said plant cells or said plants used in step e. then comprising a nucleic acid sequence allowing the expression of said protein.

[0330] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, in which the accumulation of said protein is determined via the implementation of a technique chosen from: Western blot, measurement of enzymatic activity, mass spectrometry and translational fusion. In particular, the invention relates to the method for preparing and determining an altPEP as described above, in which the accumulation of said protein is determined via the implementation of a Western blot.

[0331] The inventors have surprisingly found that the use of altPEPs makes it possible to modify the phenotypes of a plant visible at the macroscopic scale. It is therefore entirely possible to use the latter to affirm (or refute) that the peptide determined in steps a., b. and c., and possibly produced in step d. is an altPEP (or not). This is also what the so-called phenotypic comparison alternative implemented in step e allows. For example, if the peptide determined on the mRNA of a protein involved in the size of the stem of a plant causes an increase, or a decrease, in the size of the stem of a plant treated with the latter compared to an untreated plant, this means that said peptide is an altPEP capable of modulating the accumulation of said protein in the size of the stem.In the invention, the term "plant" refers generally to: a set of plant cells organized in whole or in part of a plant whatever its stage of development (including the plant in the form of a seed or young shoot); to one or more organs of the plant (such as for example the leaves, the roots, the stem, the flowers); to one or more cells of the plant; or to a mass of cells of the plant (eg a callus).

[0332] In the invention, the term "phenotype" designates, in a non-limiting manner, the characteristics visible on a macroscopic scale such as the number of lateral roots, the number of leaves, the size of the stem, the duration of flowering and the resistance to stress.In one embodiment, the invention therefore relates to the method for preparing and determining an altPEP as described above, wherein said protein is involved in at least one plant phenotype selected from: size, shape, area, volume, mass and number of leaves; size, shape, area, volume, mass and number of flowers; size of the stem (or floral stalk); root biomass; number, length and branching level of the roots; earliness of germination; earliness of budding; earliness of floral induction (or floral transition); germination vigor and duration of juvenile phase; duration of flowering; resistance to biotic stress; resistance to abiotic stress; and number of cells.

[0333] According to the invention, a protein is "involved in a phenotype" if a modification of its accumulation is associated with a modification of said phenotype. In other words, a protein is involved in a phenotype if it intervenes in the characteristic(s) corresponding to said phenotype.

[0334] In view of the above, it is understood that an object of the invention is the method for preparing and determining an altPEP as described above, in which the phenotype observed in step e. is chosen from: the size, shape, surface area, volume, mass and number of leaves; the size, shape, surface area, volume, mass and number of flowers; the size of the stem (or floral stalk); the root biomass; the number, length and level of branching of the roots; the earliness of germination; the earliness of budding; the earliness of floral induction (or floral transition); the germination vigor and the duration of the juvenile phase; the duration of flowering; the resistance to biotic stress; the resistance to abiotic stress; and the number of cells.

[0335] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, said altPEP: having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids; being capable of modulating the accumulation of a protein in a plant cell; and not being capable of modulating the accumulation of the mRNA encoding said protein, and wherein said plant cell ( / .e.celle dans laquelle on souhaite modular l'accumulation d'une protéine) appartient à une espèce végétale choisie parmi : Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis halleri, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (rapeseed), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eutrema salsugineum, Glycine max (soybean), Gossypium raimondii, Gossypium spp. (coton), Hordeum vulgare (orge), Lollium spp., Lotus japonicus (lotier), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tabac), Oryza sativa (riz), Pisum sativum (pois), Raphanus sativus, Solanum lycopersicum (tomate), Solanum melongena (aubergine), Solanum tuberosum (pomme de terre), Thellungiella halophila, Theobroma cacao, Triticum spp.(wheat), Vitis vinifera (vine) and Zea mays (corn).

[0336] In one embodiment, the invention relates to the process of preparing and determining an altPEP as previously described, wherein said plant cells or plants used in step e. belong to: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis halleri, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera strict, Brachypodium distachyon, Brassicaca, Brassicacea, Brassicacea, older turnip (rape), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eutrema salsugineum, Glycine max (soybean), Gossypium raimondii, Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (trefoil), Medicago sativa (alfalfa), Medicago truncatula (alfalfa), Nicotiana benthamiana (tobacco), Oryza sativa (rice), Pisum sativum (pea), Raphanus sativus, Solanum lycopersicum (tomato), Solanum melongena (eggplant), Solanum tuberosum (potato), Thellungiella halophila, Theobroma cacao, Triticum spp. (wheat), Vitis vinifera (vine) and Zea mays (corn).

[0337] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, in which said plant cell (i.e. the one in which it is desired to modulate the accumulation of a protein) is a cell of an algae.

[0338] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein said plant cells or said plants used in step e belong to an algae.

[0339] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, in which said protein is encoded by a gene selected from: Aae15 (Acyl-activating enzyme 15), Aae16 (AMP-dependent synthetase and ligase family protein), Abcg11 (White-brown complex-like protein), Abdcg34 (ABC transporter G family member 34), Acc1 (Acetyl-CoA Carboxylase), Agb1 (GTP binding protein beta 1), Als (Acetolactate synthase (chloroplastic)), Anac076 (NAC domain-containing protein 76), Apg9 (Autophagy 9), Arlbl (GTP-binding protein 1), Arr1 (Two-component response regulator ARR1), Arr5 (Two-component response regulator ARR5), Arr6 (Two-component response regulator ARR6), At59 (Pedate lyase family protein), Bak1 (Brassinosteroid insensitive 1 -associated receptor kinase 1), Bccpl (Acetyl-CoA Carboxylase (chloroplastic) subunit 1), Bccp2 (Acetyl-CoA Carboxylase (chloroplastic) subunit 2), Bril (Brassinosteroid insensitive 1),Bzo2h3 (bZIP transcription factor family protein), Cesa6 (Cellulose synthase A catalytic subunit 6), Cipk3 (CBL-intera ing protein kinase 3), Cks1 (Cyclin-dependent kinases regulatory subunit 1), Cobl8 (COBRA-like protein 8 precursor), Coil (Coronatine-insensitive protein 1), Cpk3 (Calcium-dependent protein kinase 3), Crk34 (Cysteine-rich receptor-like protein kinase 34), Cyp705a18 (Cytochrome P450, family 705, subfamily A, polypeptide 18), Cyp71b26 (Cytochrome P450, family 71, subfamily B, polypeptide 26), Cyp78a8 (Cytochrome P450, family 78, subfamily A, polypeptide 8), Cyp97b3 (Cytochrome P450, family 97, subfamily B, polypeptide 3), Dell (Endoribonuclease Dicer homolog 1), Dur3 (Urea-proton symporter DUR3), Ein2 (Ethylene-insensitive protein 2), Emb 175 (Pentatricopeptide repeat-containing protein), Emb2726 (Elongation factor Ts family protein), Emb9 (Di hydrofolate synthetase), Epsps (5-enolpyruvylshikimate-3-phosphate (chloroplastic)), Fnr1 (Ferredoxin-NADP[+]-oxidoreductase 1),Fve (Transducin family protein / WD-40 repeat family protein), Ga2ox7 (Gibberellin 2-beta-dioxygenase 7), Gape (Glyceraldehyde-3-phosphate dehydrogenase), Gcn2 (ABC transporter family protein), Gdi2 (Guanosine nucleotide diphosphate dissociation inhibitor 2), Gln2 (Glutamine synthetase (chloroplastic)), Gsl3 (Callose synthase 2), Hag5 (Histone acetyltransferase of the MYST family 2), Hda18 (Histone deacetylase 18), Hexol (Beta-hexosaminidase 1), Hppd (4- hydroxyphenyl-pyruvate-dioxygenase), Hsl1 (B3 domain-containing transcription repressor VAL2), Iaa31 (lndole-3-acetic acid inducible 31), Iqd28 (IQ-domain 28), Jac1 (J-domain protein required for chloroplast accumulation response 1), Jar1 (Jasmonoyl-L-amino acid synthetase), Kp1 (Kinesin-like protein 1), Lrx2 (Leucine-rich repeat / extensin 2), Mapkkk3 (Mitogen-activated protein kinase kinase kinase 3), Mapkkk5 (Mitogen-activated protein kinase kinase kinase 5), Mfp2 (Multifunctional protein 2), Mrb1 (Transmembrane protein,putative (DUF3537)), Nsp1 (Nodulation signaling pathway 1), Pds (Phytoene desaturase (chloroplastic)), Pen3 (Phosphatidylinositol 3,4,5-trisphosphate 3-phosphatase and protein- tyrosine-phosphatase), Phyb (Phytochrome B), Pif3 (Phytochrome interacting factor 3), Pizza (Brassinosteroid-related acyltransferase 1), Ppoxl (Protoporphyrinogen oxidase (chloroplastic) 1), Ppox2 (Protoporphyrinogen oxidase (chloroplastic) 2), Prp39 (Tetratricopeptide repeat (TPR)-like superfamily protein), PsbA (Photosystem II D1 protein), Pskrl (Phytosulfokin receptor 1), Rd21 (Granulin repeat cysteine protease family protein), Ringl (RING / U-box superfamily protein), Rosi (DNA glycosylase / AP lyase ROS1), Rpt4a (26S proteasome regulatory subunit 10B homolog A), Sfr6 (Mediator of RNA polymerase II transcription subunit 16), Shr (Protein SHORT-ROOT), Shy2 (Auxin-responsive protein IAA3), Ski (EIN2-like protein, nramp transporter), Sps1 (Sucrose phosphate synthase 2F), Spt (Transcription factor SPATULA),Stn8 (Serine / threonine-protein kinase), Tap46 (PP2A regulatory subunit TAP46), Topp6 (Serine / threonine-protein phosphatase PP1 isozyme 7), TubB6 (Tubulin), TubB8 (Tubulin), Ubala (RNA-binding (RRM / RBD / RNP motifs) family protein), Vim3 (E3 ubiquitin-protein ligase), Sgr1 (Magnesium dechelatase), Abi5 (Abscisic acid (ABA)-insensitive 5), Hsp101 (Heat shock protein 101), Rh10 (ATP-dependent RNA helicase) et Wus (WUSCHEL).,

[0340] In particular, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by a gene selected from: Cpk3, Dell and Nsp1. In particular, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by the Cpk3 gene. In particular, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by the Dell gene. In particular, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by the Nsp1 gene.

[0341] The genes Aae15, Aae16, abcg11, Abdcg34, Acc1, Agb1, Als, Anac076, Apg9, Arlbl, Arr1, Arr5, Arr6, At59, Bak1, Bccpl, Bccp2, Bri1, Bzo2h3, Cesaô, Cipk3, Cks1, Cobl8, Coi1, Cpk3, Crk34, Cyp705a18, Cyp71b26, Cyp78a8, Cyp97b3, Dell, Dur3, Ein2, Emb175, Emb2726, Emb9, Epsps, Fnr1, Eve, Ga2ox7, Gapc, Gcn2, Gdi2, Gln2, Gsl3, Hag5, Hda18, Hexol, Hppd, Hsl1, Iaa31, Iqd28, Jac1, Jar1, Kp1, Lrx2, Mapkkk3, Mapkkkô, Mfp2, Mrb1, Nsp1, Pds, Pen3, Phyb, Pif 3, Pizza, Ppoxl, Ppox2, Prp39, PsbA, Pskrl, Rd21, Ringl, Rosi, Rpt4a, Sfr6, Shr, Shy2, Ski, Sps1, Spt, Stn8, Tap46, Toppô, TubB6, TubB8, Ubala, Vim3, Sgr1, Abi5, Hsp101, Rh10 and l / l / us refer to the proteins indicated in parentheses. Of course, the invention also relates to homologous and / or similar genes which may have different names. For example, in A. thaliana the Gsl3 gene encoding callose synthase 2 is also called Cals2.

[0342] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NO: 1 (ORF of the Aae15 protein, A. thaliana), SEQ ID NO: 2 (ORF of the Aae16 protein, A. thaliana), SEQ ID NO: 3 (ORF of the abcg11 protein, A. thaliana), SEQ ID NO: 4 (ORF of the Abdcg34 protein, A. thaliana), SEQ ID NO: 5 (ORF of the Acc1 protein, A. thaliana), SEQ ID NO: 6 (ORF of the Agb1 protein, A. thaliana), SEQ ID NO: 7 (ORF of the protein Als, A. thaliana), SEQ ID NO: 8 (ORF of the Anac076 protein, A. thaliana), SEQ ID NO: 9 (ORF of the Apg9 protein, A. thaliana), SEQ ID NO: 10 (ORF of the Arlbl protein, A. thaliana), SEQ ID NO: 11 (ORF of the Arr1 protein, A.thaliana), SEQ ID NO: 12 (ORF of Arr5 protein, A. thaliana), SEQ ID NO: 13 (ORF of Arr6 protein, A. thaliana), SEQ ID NO: 14 (ORF of At59 protein, A. thaliana), SEQ ID NO: 15 (ORF of Ba protein, A. thaliana), SEQ ID NO: 16. (ORF of the Bccpl protein, A. thaliana), SEQ ID NO: 17 (ORF of the Bccp2 protein, A. thaliana), SEQ ID NO: 18 (ORF of the Bri1 protein, A. thaliana), SEQ ID NO: 19 (ORF of the Bzo2h3 protein, A. thaliana SEQ ID NO: 20), the NOF protein (ORF of A. thaliana). Cesa6, A. thaliana), SEQ ID NO: 21 (ORF of the protein Cipk3, A. thaliana), SEQ ID NO: 22 (ORF of the protein Cks1, A thaliana), SEQ ID NO: 23 (ORF of the protein Cobl8, A thaliana), SEQ ID NO: 24 (ORF of the protein Cobl8, A. thaliana), ID NO: 25 (ORF of Coil protein, A. thaliana), SEQ ID NO : 26 (ORF of Cpk3 protein, A. thaliana), SEQ ID NO : 27 (ORF of Cpk3 protein, A. hypochondriacus), SEQ ID NO : 28 (ORF of Cpk3 protein, B.distachyori), SEQ ID NO: 29 (ORF of Cpk3 protein, B. distachyori), SEQ ID NO: 30 (ORF of Cpk3 protein, G. max), SEQ ID NO: 31 (ORF of Cpk3 protein, G. max), SEQ ID NO: 32 (ORF of Cpk3 protein, G. max), SEQ ID NO: 32 (ORF of Cpk3 protein, G. max). : 33 (ORF of Cpk3 protein, G. max), SEQ ID NO: 34 (ORF of Cpk3 protein, O. sativa), SEQ ID NO: 35 (ORF of Cpk3 protein, O. sativa), SEQ ID NO: 36 (ORF of Cpk3 protein, S. sativa), SEQ ID NO: Cpk3 protein, Z. mays), SEQ ID NO: 38 (ORF of Cpk3 protein, Z. mays), SEQ ID NO: 39 (ORF of Cpk3 protein, Z. mays), SEQ ID NO: 40 (ORF of Cpk3 protein, B. rapa), SEQ ID NO: 41 (ORF of Cpk3 protein, B. rapa), SEQ ID NO: 41 (ORF of Cpk3 protein, rapa). SEQ ID NO : 42 (ORF of Cpk3 protein, H. vulgare), SEQ ID NO : 43 (ORF of Cpk3 protein, H. vulgare), SEQ ID NO : 44 (ORF of Cpk3 protein, S. tuberosum), SEQ ID NO : 45 (ORF of Cpk3 protein, S. tuberosum), SEQ ID NO : 46 (ORF of Cpk3 protein, A. palm). (ORF of Cpk3 protein, Mtruncatula), SEQ ID NO : 47 (ORF of Cpk3 protein, M. truncatula), SEQ ID NO : 48 (ORF of Cpk3 protein, T. aestivum), SEQ ID NO : 49 (ORF of Cpk3 protein, T. aestivum), SEQ ID NO : 50 (ORF of Cpk3 protein, T. aestivum), SEQ ID NO : 50 (ORF of Cpk3 protein, T. aestivum). ID NO: 51 (ORF of the Cpk3 protein, T. aestivum), SEQ ID NO: 52 (ORF of the Cpk3 protein, L. perenne), SEQ ID NO: 53 (ORF of the Cpk3 protein, L. perenne), SEQ ID NO: 54 (ORF of the Cpk3 protein, L. perenne), SEQ ID NO: 5 (ORF of the Cpk3 protein, 5). of the Cpk3 protein, L. perenne), SEQ ID NO: 56 (ORF of the Crk34 protein, A. thaliana), SEQ ID NO: 57 (ORF of the Cyp705a18 protein, A. thaliana), SEQ ID NO: 58 (ORF of the protein Cyp71b26, A. thaliana), AQ ID NO: 56 (ORF of the thaliana protein). the Cyp78a8 protein, A. thaliana), SEQ ID NO: 60 (ORF of the Cyp97b3 protein, A. thaliana), SEQ ID NO: 61 (ORF of the Dell protein, A. thaliana), SEQ ID NO: 62 (ORF of the Dell protein, A. thaliana), ID NO: 63 (ORF of the Dell protein, A. thaliana). TO.hypochondriacus), SEQ ID NO: 64 (ORF of the Dell protein, B. distachyon), SEQ ID NO: 65 (ORF of the Dell protein, G. max), SEQ ID NO: 66 (ORF of the Dell protein, G. max), SEQ ID NO: 67 (ORF of the Dell protein, ORF sativa, ORF: 68). Dell protein, S. lycopersicum), SEQ ID NO: 69 (ORF of Dell protein, Z. mays), SEQ ID NO: 70 (ORF of Dell protein, B. rapa), SEQ ID NO: 71 (ORF of Dell protein, H. vulgare), SEQ ID NO: 72 (ORF of Dell protein, S. mays). tuberosum), SEQ ID NO : 73 (ORF of Dell protein, M. truncatula), SEQ ID NO : 74 (ORF of Dell protein, T. aestivum), SEQ ID NO : 75 (ORF of Dell protein, T. aestivum), SEQ ID NO : 76 (ORF of Dell protein, T. aestivum), SEQ ID NO : 77 (ORF of Dell protein, T. aestivum). (ORF of the Dell protein, T. aestivum), SEQ ID NO: 78 (ORF of the Dell protein, L. perenne), SEQ ID NO: 79 (ORF of the Dell protein, L.perenne), SEQ ID NO: 80 (ORF of the protein Dur3, A thaliana), SEQ ID NO: 81 (ORF of the protein Ein2, Æ thaliana), SEQ ID NO: 82 (ORF of the protein Emb175, A. thaliana), SEQ ID NO: 83 (ORF of the protein Emb175, A. thaliana), SEQ ID NO: 84 (ORF of Emb9 protein, A. thaliana), SEQ ID NO: 85 (ORF of Epsps protein, A. thaliana), SEQ ID NO: 86 (ORF of Fnr1 protein, A. thaliana), SEQ ID NO: 87 (ORF of Fve protein, A. thaliana), SEQ ID NO: 8 (ORF of A. thaliana protein). Ga2ox7, A. thaliana), SEQ ID NO: 89 (ORF of Gape protein, N. benthamiana), SEQ ID NO: 90 (ORF of Gcn2 protein, A. thaliana), SEQ ID NO: 91 (ORF of Gdi2 protein, A. thaliana), SEQ ID NO: 92 (ORF of Gdi2 protein, A. thaliana), SEQ ID NO: 92 (ORF of Gdi2 protein, A. thaliana). SEQ ID NO: 93 (ORF of Gsl3 protein, A. thaliana), SEQ ID NO: 94 (ORF of Hag5 protein, A. thaliana), SEQ ID NO: 95 (ORF of Hda18 protein, A. thaliana), SEQ ID NO: 96 (ORF of Hexol protein, A. thaliana), SEQ ID NO: 97 (ORF of thaliana). the Hppd protein, A.thaliana), SEQ ID NO : 98 (ORF of Hsl1 protein, A. thaliana), SEQ ID NO : 99 (ORF of Iaa31 protein, A. thaliana), SEQ ID NO : 100 (ORF of Iqd28 protein, A. thaliana), SEQ ID NO : 101 (ORF of Jacd28 protein, A. thaliana ), SEQ ID NO : 101 (ORF of A. thaliana protein). ID NO: 102 (ORF of the Jar1 protein, A. thaliana), SEQ ID NO: 103 (ORF of the Kp1 protein, A. thaliana), SEQ ID NO: 104 (ORF of the Lrx2 protein, A. thaliana), SEQ ID NO: 105 (ORF of the Mak protein, A. thaliana), SEQ ID NO: A. thaliana. 106 (ORF of the protein Mapkkk5, A. thaliana), SEQ ID NO: 107 (ORF of the protein Mfp2, A. thaliana), SEQ ID NO: 108 (ORF of the protein Mrb1, A. thaliana), SEQ ID NO: 109 (ORF of the protein Nsp1, truncated SEQ1: ID: 10). of the Nsp1 protein, A. thaliana), SEQ ID NO: 111 (ORF of the Nsp1 protein, B. distachyon), SEQ ID NO: 112 (ORF of the Nsp1 protein, G. max), SEQ ID NO: 113 (ORF of the Nsp1 protein, G. max), SEQ ID NO: 114 (ORF of the Nsp1 protein, G. max). OH.sativa), SEQ ID NO : 115 (ORF of the Nsp1 protein, S. lycopersicum), SEQ ID NO : 116 (ORF of the Nsp1 protein, S. lycopersicum), SEQ ID NO : 117 (ORF of the Nsp1 protein, Z. mays), SEQ ID NO : 118 (ORF of the Nsp1 protein, Z. mays), SEQ ID NO : 119 (ORF of the Nsp1 protein, Z. mays), SEQ ID NO : 120 (ORF of the Nsp1 protein, Z. mays), SEQ ID NO : 121 (ORF of the Nsp1 protein, B. rapa), SEQ ID NO : 122 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 123 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 124 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 125 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 126 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 127 (ORF of the Nsp1 protein, H. vulgare), Nsp1, H. vulgare), SEQ ID NO : 128 (ORF of the Nsp1 protein, H. vulgare), SEQ ID NO : 129 (ORF of the Nsp1 protein, S. tuberosum), SEQ ID NO : 130 (ORF of the Nsp1 protein, S. tuberosum), SEQ ID NO : 131 (ORF of the Nsp1 protein, T. aestivum), SEQ ID NO: 132 (ORF of the Nsp1 protein, T.aestivum), SEQ ID NO: 133 (ORF of protein Nsp1, L. perenne), SEQ ID NO: 134 (ORF of protein Nsp1, L. perenne), SEQ ID NO: 135 (ORF of protein Pds, A. thaliana), SEQ ID NO: 136 (ORF of protein thaliana, A. ID3). 137 (ORF of the Phyb protein, A. thaliana), SEQ ID NO: 138 (ORF of the Pif3 protein, A. thaliana), SEQ ID NO: 139 (ORF of the Pizza protein, A thaliana), SEQ ID NO: 140 (ORF of the Ppoxl protein, A. thaliana), SEQ ID NO: 141 (ORF of the IDA protein: Ppox2, A. thaliana), SEQ ID NO: 142 (ORF of the Prp39 protein, A. thaliana), SEQ ID NO: 143 (ORF of the PsbA protein, A. thaliana), SEQ ID NO: 144 (ORF of the Pskrl protein, A. thaliana), SEQ ID NO: 215 (ORF of the Rp39 protein, A. thaliana). A. thaliana), SEQ ID NO: 146 (ORF of the Ringl protein, A. thaliana), SEQ ID NO: 147 (ORF of the Rosi protein, A. thaliana), SEQ ID NO: 148 (ORF of the Rpt4a protein, A. thaliana), SEQ ID NO: 149 (ORF of the Sfr protein, A. thaliana).thaliana), SEQ ID NO : 150 (ORF of the Shr protein, A. thaliana), SEQ ID NO : 151 (ORF of the Shy2 protein, A. thaliana), SEQ ID NO : 152 (ORF of the Ski protein, M. truncatula), SEQ ID NO : 153 (ORF of the Ski protein, A. thaliana ), SEQ ID NO : NO 154 (ORF of the protein Spt, A. thaliana), SEQ ID NO: 155 (ORF of the protein Stn8, A. thaliana), SEQ ID NO: 156 (ORF of the protein Tap46, A. thaliana), SEQ ID NO: 157 (ORF of the protein Topp6, A. thaliana), SEQ ID NO: TubB6 protein, A. thaliana), SEQ ID NO: 159 (ORF of the TubB8 protein, A. thaliana), SEQ ID NO: 160 (ORF of the llbala protein, A. thaliana), SEQ ID NO: 161 (ORF of the Vim3 protein, A. thaliana), SEQ ID NO: 38 (ORF of the Sgr protein (ORF, A. thaliana). , A. thaliana), SEQ ID NO: 382 (ORF of Abi5 protein, A. thaliana), SEQ ID NO: 383 (ORF of Hsp101 protein, A. thaliana), SEQ ID NO: 384 (ORF of Rh10 protein, M. truncatula) and SEQ ID NO: 385 (ORF of Abi5 protein, A. thaliana). thaliana).

[0343] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0344] In particular, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 61 to 79 (Dell).In particular, the invention relates to the method for preparing and determining an altPEP as described above, in which said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0345] By "percentage identity" between two nucleic acid (or amino acid) sequences, we mean a percentage of nucleotides (or amino acid residues) that are identical between the two sequences to be compared, obtained after the best alignment. This percentage is purely statistical and the differences between the two sequences are randomly distributed over the entire length of the sequences. The best alignment (or optimal alignment) is the alignment for which the percentage identity between the two sequences to be compared, as calculated below, is the highest. Sequence comparisons between two nucleic acid (or amino acid) sequences are traditionally performed by comparing these sequences after having aligned them optimally, said comparison being performed by segment or comparison window to identify and compare local regions of sequence similarity.Optimal alignment of sequences for comparison can be performed manually or by means of algorithms and software available to those skilled in the art, for example, the BLAST platform or the MatGat program (Campanella, Bitincka and Smalley, 2003).

[0346] The percentage identity between two sequences is determined by comparing these two optimally aligned sequences by comparison window in which the region of the sequence to be compared may include additions or deletions relative to the reference sequence for optimal alignment between these two sequences. The percentage identity is calculated by determining the number of identical positions for which the nucleotide (or amino acid) is identical between the two sequences, dividing this number of identical positions by the total number of positions in the comparison window and multiplying the result obtained by 100.

[0347] For the purposes of the invention, it is understood in the invention that sequences having “at least 80% identity” with a reference sequence may in particular have at least 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100% identity with said reference sequence.

[0348] In one embodiment, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385. In one embodiment, the invention also relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0349] In particular, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention relates to the method for preparing and determining an altPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0350] In another way of manufacturing, the invention concerns the preparation and determination process of an altPEP as described above, where the peptide sequence is chosen for the sequences: SEQ ID NO: 224 (AtDCL1alt18), SEQ ID NO: 225 (CrDCL1alt18), SEQ ID NO : 226 (EsDCL1alt18), SEQ ID NO : 227 (AIDCL1alt19), SEQ ID NO : 228 (CsDCL1alt19), SEQ ID NO : 229 (RsDCL1alt15), SEQ ID NO : 230 (BnDCL1alt14), SEQ ID NO : 231 (BoDCL1alt15), SEQ ID NO : 232 (BRDCL1alt17), SEQ ID NO : 233 (BsEIN2alt1), SEQ ID NO : 234 (CgEIN2alt1), SEQ ID NO : 235 (CrEIN2alt1), SEQ ID NO : 236 (EsEIN2alt1), SEQ ID NO : 237 (ThEI N2alt1), SEQ ID NO : 238 (BrEIN2alt1), SEQ ID NO : 239 (BoEIN2alt1), SEQ ID NO : 240 (BnEIN2alt1), SEQ ID NO : 241 (AtEIN2alt1), SEQ ID NO : 242 (AIEI N2alt1 ), SEQ ID NO : 243 (AtAP2alt1), SEQ ID NO : 244 (AIAP2alt1), SEQ ID NO : 245 (BoAP2alt1), SEQ ID NO : 246 (CgAP2alt1), SEQ ID NO : 247 (CrAP2alt1), SEQ ID NO : 248 (BrAP2alt1), SEQ ID NO : 249 (BsAP2alt1),SEQ ID NO : 250 (EsAP2alt1), SEQ ID NO : 251 (ThAP2alt1), SEQ ID NO : 252 (altPEP_DCL1), SEQ ID NO : 253 (altPEP_CYP78A8), SEQ ID NO : 254 (altPEP_PRP39), SEQ ID NO : 255 (altPEP_PIF3), SEQ ID NO : 256 (altPEP_PIF3), SEQ ID NO : 257 (altPEP_IQD28), SEQ ID NO : 258 (altPEP_AT59), SEQ ID NO : 259 (altPEP_AT59), SEQ ID NO : 260 (altPEP_ABCG11), SEQ ID NO : 261 (altPEP_ABCG11), SEQ ID NO : 262 (altPEP_ABCG11), SEQ ID NO : 263 (altPEP_ABCG11), SEQ ID NO : 264 (altPEP_ABCG11), SEQ ID NO : 265 (altPEP_ABCG11), SEQ ID NO : 266 (altPEP_ABCG11), SEQ ID NO : 267 (altPEP_RD21), SEQ ID NO : 268 (altPEP_RD21), SEQ ID NO : 269 (altPEP_RD21), SEQ ID NO : 270 (altPEP_RD21), SEQ ID NO : 271 (altPEP_LRX2), SEQ ID NO : 272 (altPEP_LRX2), SEQ ID NO : 273 (altPEP_LRX2), SEQ ID NO : 274 (altPEP_JAC1), SEQ ID NO : 275 (altPEP_JAC1), SEQ ID NO : 276 (altPEP_JAC1), SEQ ID NO : 277 (altPEP_PSKR1), SEQ ID NO : 278 (altPEP_PSKR1), SEQ ID NO : 279 (altPEP_PSKR1), SEQ ID NO : 280 (altPEP_PSKR1),SEQ ID NO : 281 (altPEP_PSKR1), SEQ ID NO : 282 (altPEP_PSKR1), SEQ ID NO : 283 (altPEP_FVE), SEQ ID NO : 284 (altPEP_FVE), SEQ ID NO : 285 (altPEPJJBAIA :), SEQ ID NO : 285 (altPEP_PSKR1), SEQ ID NO : 287 (altPEP_CIPK3), SEQ ID NO : 288 (altPEP_APG9), SEQ ID NO : 289 (altPEP_APG9), SEQ ID NO : 290 (altPEP_COI1), SEQ ID NO : 291 (altPEP_COI1), SEQ ID NO : 292 (PEQ ID NO1), SEQ ID NO : : 293 (altPEP_COI1), SEQ ID NO : 294 (altPEP_COI1), SEQ ID NO : 295 (altPEP_COI1), SEQ ID NO : 296 (altPEP_COI1), SEQ ID NO : 297 (altPEP_COI1), SEQ ID NO : 298 (altPEP_COI1), SEQ ID NO : 298 299 (altPEP_MFP2), SEQ ID NO : 300 (altPEP_MFP2), SEQ ID NO : 301 (altPEP_MFP2), SEQ ID NO : 302 (altPEP_COBL8), SEQ ID NO : 303 (altPEP_IAA31), SEQ ID NO : 303 (altPEP_IAA31), SEQ ID NO : 300 (altPEP_YP4A), SEQ ID NO : 305 (altPEP_AAE16), SEQ ID NO : 306 (altPEP_AAE16), SEQ ID NO : 307 (altPEP_CYP71 B26), SEQ ID NO : 308 (altPEP_CYP71 B26), SEQ ID NO : 309 (altPEP_CYP71 B26), SEQ ID NO : 309 (altPEP_CYP71), SEQ ID NO : 307 310 (altPEP_CYP71 B26), SEQ ID NO : 311 (altPEP_CYP71 B26),SEQ ID NO : 312 (altPEP_CYP71 B26), SEQ ID NO : 313 (altPEP_KP1), SEQ ID NO : 314 (altPEP_KP1), SEQ ID NO : 315 (altPEP_PEN3), SEQ ID NO : 316 (altPEP_PEN3), SEQ ID NO : 317 (altPEP_HEXO1), SEQ ID NO : 318 (altPEP_GDI2), SEQ ID NO : 319 (altPEP_GDI2), SEQ ID NO : 320 (altPEP_GDI2), SEQ ID NO : 321 (altPEP_GDI2), SEQ ID NO : 322 (altPEP_GDI2), SEQ ID NO : 323 (altPEP_SFR6), SEQ ID NO : 324 (altPEP_CRK34), SEQ ID NO : 325 (altPEP_AAE15), SEQ ID NO : 326 (altPEP_CYP97B3), SEQ ID NO : 327 (altPEP_CYP97B3), SEQ ID NO : 328 (altPEP_CYP97B3), SEQ ID NO : 329 (altPEP_CYP97B3), SEQ ID NO : 330 (altPEP_AMB2726), SEQ ID NO : 331 (altPEP_HSL1), SEQ ID NO : 332 (altPEP_HSL1), SEQ ID NO : 333 (altPEP_HSL1), SEQ ID NO : 334 (altPEP_ANAC076), SEQ ID NO : 335 (altPEP_STN8), SEQ ID NO : 336 (altPEP_EMB175), SEQ ID NO : 337 (altPEP_EMB175), SEQ ID NO : 338 (altPEP_EMB175), SEQ ID NO : 339 (altPEP_EMB175), SEQ ID NO : 340 (altPEP_EMB175), SEQ ID NO : 341 (altPEP_GCN2), SEQ ID NO : 342 (altPEP_SPS1),SEQ ID NO: 343 (altPEP_SPS1), SEQ ID NO: 344 (altPEP_SPS1), SEQ ID NO: 345 (altPEP_SPS1), SEQ ID NO: 346 (altPEP_BZO2H3), SEQ ID NO: 347 (altPEP_VIM3), SEQ ID NO: 348 (altPEP_EMB9), SEQ ID NO: 349 (altPEP_EMB9), SEQ ID NO: 350 (altPEP_RPT4A), SEQ ID NO: 351 (altPEP_TOPP6), SEQ ID NO: 352 (altPEP_DUR3), SEQ ID NO: 353 (altPEP_DUR3), SEQ ID NO: 354 (altPEP_DUR3), SEQ ID NO: 355 (altPEP_ARLB1), SEQ ID NO: 356 (altPEP_ARLB1), SEQ ID NO: 357 (altPEP_HDA18), SEQ ID NO: 358 (altPEP_HDA18), SEQ ID NO: 359 (altPEP_HDA18), SEQ ID NO: 360 (altPEP_CESA6), SEQ ID NO: 361 (altPEP_FNR1), SEQ ID NO: 362 (altPEP_FNR1), SEQ ID NO: 363 (altPEP_FNR1), SEQ ID NO: 364 (EIN2alt1), SEQ ID NO: 365 (EIN2alt2) and SEQ ID NO: 366 (EIN2alt3). In a second aspect, the subject of the above invention is an altPEP as obtained by implementing the method as described above. According to this same aspect, the invention also relates to an isolated altPEP, of 4 to 70 amino acids,in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a naturally translated fragment of a naturally translated nucleic acid sequence on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said altPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.,

[0351] In one embodiment, the invention relates to isolated altPEP as previously described, said fragment having a size of 3n nucleotides, n being comprised: from 4 to 41; from 5 to 40; from 7 to 20; or from 8 to 15.

[0352] In other words, the invention relates to isolated altPEP as described above, said isolated altPEP comprising s, 6, 7, 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, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69 or 70 amino acids.

[0353] In particular, the invention relates to isolated altPEP as described above, said isolated altPEP comprising from 4 to 41 amino acids. In particular, the invention relates to isolated altPEP as described above, said isolated altPEP comprising from 5 to 40 amino acids. In particular, the invention relates to isolated altPEP as described above, said isolated altPEP comprising from 7 to 20 amino acids. In particular, the invention also relates to isolated altPEP as described above, said isolated altPEP comprising from 8 to 15 amino acids.

[0354] In one embodiment, the invention relates to isolated altPEP as described above, wherein the size of said isolated altPEP is smaller than that of said protein.

[0355] In one embodiment, the invention relates to the isolated altPEP as described above, said fragment comprising: an initiator codon encoding an initiator methionine; and a STOP codon selected from the codons: UAG, UGA and UAA, and said fragment being selected from an open reading frame shifted by one or two nucleotides relative to that encoding said protein. In one embodiment, the invention relates to the isolated altPEP as described above, wherein the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention relates to the isolated altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention also relates to the isolated altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In other words, the invention relates to the isolated altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0356] In one embodiment, the invention relates to isolated altPEP as described above, wherein said isolated altPEP is capable of increasing the accumulation of said protein in said plant cell.

[0357] In one embodiment, the invention relates to isolated altPEP as described above, wherein said isolated altPEP is capable of decreasing the accumulation of said protein in said plant cell.

[0358] In one embodiment, the invention relates to isolated altPEP as described above, wherein said isolated altPEP is a synthetic peptide.

[0359] In one embodiment, the invention relates to altPEP as described above, wherein said isolated altPEP is a recombinant peptide.

[0360] In one embodiment, the invention relates to isolated altPEP as described above, wherein said isolated altPEP is a hydrophobic peptide or a hydrophilic peptide.

[0361] In one embodiment, the invention relates to isolated altPEP as described above, wherein said protein is naturally present in said plant cell.

[0362] In one embodiment, the invention relates to isolated altPEP as described above, wherein said protein is not naturally present in said plant cell. In particular, the invention relates to isolated altPEP as described above, wherein said protein is encoded by a transgene artificially introduced into said plant cell. In particular, the invention relates to isolated altPEP as described above, wherein said protein is encoded by a vector artificially introduced into said plant cell.

[0363] In one embodiment, the invention relates to the isolated altPEP as previously described, wherein said plant cell ( / .e. the one in which it is desired to modulate the accumulation of a protein) belongs to a plant species: Alopecurus myurosis, Alopecurus myurosis hypochondriacus, Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis halleri, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (Campella), Capellina grandi, Capellina Capsella rubella, Carica papaya, Eutrema salsugineum, Glycine max (soybean), Gossypium raimondii, Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (lotier), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tabac), Oryza sativa (riz), Pisum sativum (pois), Raphanus sativus, Solanum lycopersicum (tomate), Solanum melongena (aubergine), Solanum tuberosum (pomme de terre), Thellungiella halophila, Theobroma cacao, Triticum spp. (blé), Vitis vinifera (vines) and Zea mays (maize).

[0364] In a way of realization, the invention concerns the other PEP isolated as previously described, which is why the plant cells are one of the other cells.

[0365] In one embodiment, the invention relates to the isolated altPEP as described above, wherein said protein is encoded by a gene selected from: Aae15, Aae16, abcg11, Abdcg34, Acc1, Agb1, Als, Anac076, Apg9, Arlbl, Arr1, Arr5, Arr6, At59, Bak1, Bccpl, Bccp2, Bri1, Bzo2h3, Cesaô, Cipk3, Cks1, Cobl8, Coi1, Cpk3, Crk34, Cyp705a18, Cyp71b26, Cyp78a8, Cyp97b3, Dell, Dur3, Ein2, Emb175, Emb2726, Emb9, Epsps, Fnr1, Eve, Ga2ox7, Gape, Gcn2, Gdi2, G / n2, Gs / 3, Hag5, Hda18, Hexol, Hppd, Hsl1, Iaa31, Iqd28, Jac1, Jar1, Kp1, Lrx2, Mapkkk3, Mapkkkô, Mfp2, Mrb1, Nsp1, Pds, Pen3, Phyb, Pif 3, Pizza, Ppoxl, Ppox2, Prp39, PsbA, Pskrl, Rd21, Ringl, Rosi, Rpt4a, Sfr6, Shr, Shy2, Ski, Sps1, Spt, Stn8, Tap46, Toppô, TubB6, TubB8, Ubala, \ / im3, Sgr1, Abi5, Hsp101, RhIO and Wus.

[0366] In particular, the invention relates to isolated altPEP as described above, wherein said protein is encoded by a gene selected from the genes: Cpk3, Dell and Nsp1. In particular, the invention relates to isolated altPEP as described above, wherein said protein is encoded by the Cpk3 gene. In particular, the invention relates to isolated altPEP as described above, wherein said protein is encoded by the Dell gene. In particular, the invention relates to isolated altPEP as described above, wherein said protein is encoded by the Nsp1 gene.

[0367] In one embodiment, the invention relates to isolated altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence selected from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385.

[0368] In particular, the invention relates to the isolated altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1). In particular, the invention also relates to the isolated altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3).In particular, the invention also relates to the isolated altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence selected from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention also relates to the isolated altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence selected from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0369] In one embodiment, the invention relates to the isolated altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385. The invention relates in particular to the isolated altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0370] In particular, the invention relates to the isolated altPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the isolated altPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention relates to the isolated altPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0371] In another embodiment, the invention relates to the isolated altPEP as described above, wherein the sequence of said peptide is chosen from the sequences: SEQ ID NOs: 224 to 366.

[0372] In one embodiment, the invention relates to the isolated altPEP as described above, wherein said protein is involved in at least one plant phenotype selected from: leaf size, shape, area, volume, mass and number; flower size, shape, area, volume, mass and number; stem (or floral stalk) size; root biomass; root number, length and branching level; germination precocity; budding precocity; floral induction (or floral transition) precocity; germination vigor and juvenile phase duration; flowering duration; biotic stress resistance; abiotic stress resistance; and cell number.

[0373] In the invention, an altPEP may be fused or linked to one or more molecules that facilitate the entry of altPEP into the cell. Examples of these molecules include peptides and palmitic acid. Examples of these molecules include penetrating peptides (Numata, K., et al. Library screening of cell-penetrating peptide for BY-2 cells, leaves of Arabidopsis, tobacco, tomato, poplar, and rice callus. Sci Rep 8, 10966 (2018).) and palmitic acid. The term "penetrating peptide" (hereinafter CPP) refers to small peptides that penetrate cellular lipid bilayers or destabilize cellular membranes. CPPs can be classified into three groups: cationic, amphipathic, and hydrophobic. In particular:

[0374] - cationic CPPs contain many positively charged amino acids, such as lysine (Lys) and arginine (Arg);

[0375] - Amphipathic CPPs are generally composed of an alternating sequence of polar and non-polar amino acids; and - Hydrophobic CPPs consist of non-polar amino acids with relatively low net charges.

[0376] In one embodiment, the invention relates to isolated altPEP as described above, said isolated altPEP being fused to a peptide facilitating its entry into the plant cell. In particular, the invention relates to altPEP as described above, said altPEP being fused to a penetrating peptide.

[0377] In one embodiment, the invention relates to isolated altPEP as described above, said isolated altPEP being fused at the N-terminus or the C-terminus with said peptide facilitating its entry into the plant cell. In particular, the invention relates to altPEP as described above, said altPEP being fused at the N-terminus or the C-terminus with said penetrating peptide.

[0378] In one embodiment, the invention relates to isolated altPEP as described above, said isolated altPEP being fused with: the TAT peptide (SEQ ID NO: 380); penetratin; a polyhistidine peptide (in particular a peptide of at least 4 histidine residues); or a polyarginine peptide (in particular a peptide of 4 arginine residues).

[0379] In one embodiment, the invention relates to isolated altPEP as described above, said isolated altPEP being linked to one or more palmitic acid molecules.

[0380] In one embodiment, the invention relates to isolated altPEP as described above, said isolated altPEP being linked at the N-terminus or at the C-terminus to one or more palmitic acid molecules.

[0381] On this point, it should be noted that the amount of altPEP required to modulate the accumulation of a protein may vary depending on whether or not the altPEP is modified with one of the molecules facilitating its cellular penetration.

[0382] In a third aspect, the above invention relates to a nucleic acid encoding an altPEP as described above. According to this same aspect, the invention also relates to a nucleic acid of 3n nucleotides, which nucleic acid corresponds to a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA.

[0383] In one embodiment, the invention relates to the nucleic acid as described above, said fragment comprising: an initiator codon encoding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen from an open reading frame shifted by one or two nucleotides relative to that encoding said protein.

[0384] In one embodiment, the invention relates to the nucleic acid as described above, wherein the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the nucleic acid as described above, wherein the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the nucleic acid as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the nucleic acid as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0385] In particular, the invention relates to the nucleic acid as described above, where n is comprised: from 4 to 70; from 4 to 41; from 5 to 40; from 7 to 20; or from 8 to 15.

[0386] In another aspect, the above invention relates to a composition comprising an altPEP as described above as an active ingredient. In another embodiment, the above invention relates to a composition comprising an altPEP as an active ingredient, said altPEP:

[0387] - having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA; and

[0388] - being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0389] In one embodiment, the invention relates to the composition as described above, in which said fragment comprises: an initiator codon encoding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen from an open reading frame shifted by one or two nucleotides relative to that encoding said protein.

[0390] In one embodiment, the invention relates to the composition as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the composition as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the composition as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the composition as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0391] In one embodiment, the invention relates to the composition as described above, wherein said altPEP is at a concentration of 10' 9 M to 10' 3Mr. On this point, it should be noted on the one hand that the composition of the invention does not exist in its natural state and this is all the more true since such a concentration of altPEP cannot exist within a plant cell. In addition, and by "concentration of 10' 9 M to 10' 3 M", we mean that the altPEP concentration can be understood from 10' 9 at 10' 4 M, 10' 8 at 10' 4 M, 10' 9 at 10' 5 M, 10' 8 at 10' 5 M, as it can be understood from 5 pM to 500 pM, from 30 pM to 70 pM, or even be 50 pM.

[0392] In particular, the invention relates to the composition as described above, in which said altPEP is at a concentration of 10' 9 at 10' 4 M, 10' 8 at 10' 4 M, 10' 9 at 10' 5 M or 10' 8 at 10' 5M. In particular, the invention relates to the composition as described above, wherein said altPEP is at a concentration of from 5 pM to 500 pM or from 30 pM to 70 pM. In particular, the invention relates to the composition as described above, wherein said altPEP is at a concentration of 50 pM. In a non-limiting manner, this concentration may also be 10' 9 M, 10' 8 M, 10' 7 M, 10' 6 M, IO' 5 M or IO' 4 Mr.

[0393] In view of the above, it is understood that the invention also relates to the composition comprising an altPEP as an active substance, said altPEP: having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA; being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein; and being in particular at a concentration of from 5 pM to 500 pM or from 30 pM to 70 pM, or being in particular at a concentration of 50 pM.

[0394] It should be noted that by "composition comprising an altPEP", it is meant that the composition of the invention comprises at least one altPEP. That is to say that a mixture of altPEPs is conceivable, said altPEPs being able to target the same protein or several proteins depending on the nucleic acid fragment from which they are derived. In this regard, the aforementioned concentrations relate either to the mixture of altPEPs as such, or to each of the altPEPs of said mixture, said altPEPs being able to be at the same concentration or being able to be at different concentrations among those mentioned above. In one embodiment, the invention relates to the composition as described above, said composition being a phytopharmaceutical composition, a herbicidal composition or a coating composition, in particular said coating composition further comprising at least one fixing agent.

[0395] In particular, the invention relates to the composition as described above, said composition being a phytopharmaceutical composition. In particular, the invention relates to the composition as described above, said composition being a herbicidal composition. In particular, the invention relates to the composition as described above, said composition being a coating composition. Preferably, the invention relates to the composition as described above, said composition being a coating composition further comprising at least one fixing agent.

[0396] In one embodiment, the invention relates to the composition as described above, said composition further comprising at least one solvent. Preferably, said solvent is chosen from: acetone, acetonitrile, acetic acid, formic acid, dimethyl adipate, benzyl acetate, bi-butyl carbonate, dimethyl sulfoxide (DMSO), water, dimethyl glutarate, ammonium hydroxide, isobutanol, iso-propanol, diethyl hexyl lactate, light aromatic naphtha solvent, heavy aromatic naphtha solvent, diethyl succinate and mixtures thereof (e.g. mixture [water; acetic acid]; [acetonitrile; acetic acid], [water, acetonitrile; acetic acid], [water; DMSO], [water; acetonitrile] or [water; ammonium hydroxide]).

[0397] The solubility properties of altPEPs are determined in particular by their amino acid composition. Hydrophilic altPEPs can be solubilized and packaged in aqueous solutions, such as water. Hydrophobic altPEPs can be solubilized and packaged in solvents, such as organic solvents.

[0398] For treatment of plants with altPEPs, organic solvents are non-toxic solvents for plants in small quantities, that is to say they do not have a deleterious effect on the development of the plant. In a non-limiting manner, the organic solvents can be those mentioned above and in particular chosen from acetonitrile and acetic acid.

[0399] As indicated above, altPEPs can also be solubilized and packaged in solvent mixtures, such as, for example, an organic solvent mixture [acetonitrile; acetic acid], a mixture [water; DMSO] in a volume:volume ratio of 99:1 to 1:99, a mixture [water; acetonitrile] in a volume:volume ratio of 99:1 to 1:99, or a mixture [water; ammonium hydroxide] in a volume:volume ratio of 99:1 to 99.9:0.1. altPEPs can also be solubilized in a solution comprising 50% acetonitrile, 10% acetic acid, and 40% water (volume / volume / volume).

[0400] In one embodiment, the invention relates to the composition as described above, said composition further comprising at least one diluent.

[0401] In one embodiment, the invention relates to the composition as described above, said composition further comprising at least one adjuvant.

[0402] In one embodiment, the invention relates to the composition as described above, said composition further comprising at least one fixing agent.

[0403] By "fixing agent" is meant a chemical or natural agent which allows the composition of the invention to be bonded to a plant seed so as to coat said plant seed. It also means a substance making it possible to apply and hold the active substance(s) on the grain. Among the available fixing agents are carboxymethyl cellulose (CMC) and gum arabic. In addition, and in a non-limiting manner, a fixing agent may comprise organic solvents, water, dispersants, emulsifiers, surfactants, wetting agents and colorants.

[0404] In one embodiment, the invention relates to the composition as described above, said composition further comprising at least one plant nutrient. In particular, the invention relates to the composition as described above, said composition further comprising at least one fixing agent and at least one plant nutrient.

[0405] By "plant nutrient" we mean an element assimilated by the plant to enable its development. A plant nutrient may be chosen, without limitation, from: nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, manganese, iron, copper, boron, zinc, molybdenum and mixtures thereof.

[0406] In view of the above, it is understood that another aspect of the invention relates to a coated seed comprising a plant seed, said plant seed being coated with a coating composition as described above. The coating can be carried out according to the methods conventionally used in the food industry and can be obtained using a material capable of disintegrating in a solvent or in the earth, such as a binder or clay.

[0407] According to the invention, the coating can be used to confer particular properties to a seed in combination with an altPEP, such as improved growth or resistance to certain biotic or abiotic stresses.

[0408] In one embodiment, the invention relates to the enrobed seed as described previously, wherein said plant seed has a plant species selected among: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis, Arabidopsis, Arabidopsis, halley, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (rapeseed), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eutrema salsugineum, Gsopium massy, ​​Goxpium mass raimondii, Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (trefoil), Medicago sativa (alfalfa), Medicago truncatula (alfalfa), Nicotiana benthamiana (tobacco), Oryza sativa (rice), Pisum sativum (pea), Raphanus sativus, Solanum lycopersicum (tomato), Solanum melongena (eggplant), Solanum tuberosum (potato), Thellungiella halophila, Theobroma cacao, Triticum spp. (wheat), Vitis vinifera (vine) and Zea mays (corn).

[0409] In one embodiment, the invention relates to the coated seed as described above, said seed being treated by soaking in a composition containing an altPEP. During soaking, the seed is then immersed totally or partially in a composition containing an altPEP.

[0410] In another aspect, the invention relates to a use of an altPEP as a phytosanitary agent for modulating the accumulation of a protein in a plant cell, said altPEP having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of said protein encoded by said mRNA, said altPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.In one embodiment, the invention relates to the use of an altPEP as described above, wherein said fragment comprises: an initiator codon encoding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen from an open reading frame shifted by one or two nucleotides relative to that encoding said protein.

[0411] In one embodiment, the invention relates to the use of an altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the use of an altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the use of an altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the use of an altPEP as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0412] In one embodiment, the invention relates to the use of an altPEP as described above to increase the accumulation of said protein in the plant cell. The presence of the altPEP causes the amount of said protein in the treated plant cell to be greater than that in an untreated plant cell.

[0413] In one embodiment, the invention relates to the use of an altPEP as described above to decrease (inhibit) the accumulation of said protein in the plant cell. The presence of the altPEP causes the amount of said protein in the treated plant cell to be lower than that in an untreated plant cell.

[0414] In one embodiment, the invention relates to the use of an altPEP as described above, wherein said altPEP is produced outside of said plant cell before being introduced into said plant cell. In one embodiment, the invention relates to the use of an altPEP as described above, wherein said altPEP is a synthetic peptide.

[0415] In one embodiment, the invention relates to the use of an altPEP as described above, wherein said altPEP is an isolated peptide.

[0416] In one embodiment, the invention relates to the use of an altPEP as described above, wherein said altPEP is a recombinant peptide.

[0417] In one embodiment, the invention relates to the use of an altPEP as described above, wherein said altPEP is a hydrophobic peptide or a hydrophilic peptide.

[0418] In one embodiment, the invention relates to the use of an altPEP as described above, wherein said altPEP is introduced into said plant cell in the form of a nucleic acid encoding said altPEP. In particular, the invention relates to the use of an altPEP as described above, wherein said altPEP is introduced into said plant cell in the form of a nucleic acid encoding said altPEP and comprising the means for expressing it.

[0419] In one embodiment, the invention relates to the use of an altPEP as described above, wherein said protein is naturally present in said plant cell.

[0420] In one embodiment, the invention relates to the use of an altPEP as described above, wherein said protein is not naturally present in said plant cell. In particular, the invention relates to the use of an altPEP as described above, wherein said protein is encoded by a transgene artificially introduced into said plant cell. In particular, the invention relates to the use of an altPEP as described above, wherein said protein is encoded by a vector artificially introduced into said plant cell.

[0421] In one embodiment, the invention relates to the use of an altPEP as described above, wherein the accumulation of said protein is determined via the implementation of a technique chosen from: Western blot, measurement of enzymatic activity, mass spectrometry and translational fusion. In particular, the invention relates to the use of an altPEP as described above, wherein the accumulation of said protein is determined via the implementation of a Western blot. In one embodiment, the invention relates to the use of an altPEP as described above, wherein said altPEP has a size of 4 to 41 amino acids, 5 to 40 amino acids, 7 to 20 amino acids or more particularly a size of 8 to 15 amino acids.In particular, said altPEP has a size of 4, 5, 6, 7, 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, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61 , 62, 63, 64, 65, 66, 67, 68, 69 or 70 amino acids.

[0422] In one embodiment, the invention relates to the use of an altPEP as previously described, wherein said plant cell belongs to a plant species selected from: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, tuberidus, Arabidophus, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (rapeseed), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eut. Gossypium raimondii, Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (lotier), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tabac), Oryza sativa (riz), Pisum sativum (pois), Raphanus sativus, Solanum lycopersicum (tomate), Solanum melongena (aubergine), Solanum tuberosum (pomme de terre), Thellungiella halophila, Theobroma cacao, Triticum spp. (blé), Vitis vinifera (vines) and Zea mays (maize).

[0423] In particular, the invention concerns the use of another PEP as described above, which is why the plant cells are the cells of another.

[0424] In one embodiment, the invention relates to the use of an altPEP as described above, wherein said protein is encoded by a gene selected from: Aae15, Aae16, abcg11, Abdcg34, Acc1, Agb1, Als, Anac076, Apg9, Arlbl, Arr1, Arr5, Arr6, At59, Bak1, Bccpl, Bccp2, Bri1, Bzo2h3, Cesaô, Cipk3, Cks1, Cobl8, Coi1, Cpk3, Crk34, Cyp705a18, Cyp71b26, Cyp78a8, Cyp97b3, Dell, Dur3, Ein2, Emb175, Emb2726, Emb9, Epsps, Fnr1, Eve, Ga2ox7, Gapc, Gcn2, Gdi2, Gln2, Gsl3, Hag5, Hda18, Hexol, Hppd, Hsl1, Iaa31, Iqd28, Jac1, Jar1, Kp1, Lrx2, Mapkkk3, Mapkkkô, Mfp2, Mrb1, Nsp1, Pds, Pen3, Phyb, Pif3, Pizza, Ppoxl, Ppox2, Prp39, PsbA, Pskrl, Rd21, Ringl, Rosi, Rpt4a, Sfr6, Shr, Shy2, Ski, Sps1, Spt, Stn8, Tap46, Toppô, TubB6, TubB8, Ubala, Vim3, Sgr1, Abi5, Hsp101, Rh10 and Wus.

[0425] In one embodiment, the invention relates to the use of an altPEP as described above, in which said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385.

[0426] In one embodiment, the invention relates to the use of an altPEP as described above, wherein said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0427] In particular, the invention relates to the use of an altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the use of an altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 61 to 79 (Dell).In particular, the invention relates to the use of an altPEP as described above, in which said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0428] In one embodiment, the invention relates to the use of an altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385. In one embodiment, the invention also relates to the use of an altPEP as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0429] In particular, the invention relates to the use of an altPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the use of an altPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention relates to the use of an altPEP as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0430] In another embodiment, the invention relates to the use of an altPEP as described above, wherein said altPEP is selected from the sequences: SEQ ID NOs: 224 to 366.

[0431] In another embodiment, the invention relates to the use of an altPEP as described above, wherein said protein is involved in at least one plant phenotype selected from: size, shape, surface area, volume, mass and number of leaves; size, shape, surface area, volume, mass and number of flowers; size of the stem (or floral stalk); root biomass; number, length and branching level of the roots; earliness of germination; earliness of budding; earliness of floral induction (or floral transition); germination vigor and duration of juvenile phase; duration of flowering; resistance to biotic stress; resistance to abiotic stress; and number of cells.

[0432] In another embodiment, the invention relates to the use of an altPEP as described above, to modulate the accumulation of a recombinant protein whose nucleic acid sequence which encodes it corresponds to the fusion of the nucleic acid sequences of two distinct genes.

[0433] In particular, the coding sequence of at least one of the two genes is that of a reporter gene, for example a gene coding for a fluorescent protein (such as GFP) or a protein enabling the plant's resistance to a compound.

[0434] In one embodiment, the invention relates to the use of an altPEP as described above, for modulating the accumulation of a recombinant protein whose nucleic acid sequence which codes it corresponds to the fusion: of a nucleic acid sequence known to be non-coding of a first gene; and of a nucleic acid sequence coding for a second gene, the sequence of said altPEP corresponding to the translation via the genetic code of a fragment of the nucleic acid sequence known to be non-coding of the first gene.

[0435] In another aspect, the above invention relates to a method for modulating the accumulation of a protein in a plant cell comprising a step of introducing: an altPEP; or a nucleic acid encoding said altPEP and the means for expressing it, into said plant cell, the introduction of said altPEP resulting in a modulation of the amount of said protein in said plant cell, said altPEP having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of said protein encoded by said mRNA, said altPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0436] In one embodiment, the invention relates to the method as described above, wherein said fragment comprises: an initiator codon encoding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen from an open reading frame shifted by one or two nucleotides relative to that encoding said protein.

[0437] In one embodiment, the invention relates to the method as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the method as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the method as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the method as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0438] In one embodiment, the invention relates to the method as described above, said method making it possible to: promote the development of a plant; or slow down or prevent the development of a plant.

[0439] In particular, the invention relates to the method as described above, said method making it possible to promote the development of a plant. In particular, the invention relates to the method as described above, said method making it possible to slow down or prevent the development of a plant.

[0440] In one embodiment, the invention relates to the method as described above for increasing the accumulation of said protein in the plant cell. The presence of altPEP causes the amount of said protein in the treated plant cell to be greater than that in an untreated plant cell.

[0441] In one embodiment, the invention relates to the method as described above for decreasing (inhibiting) the accumulation of said protein in the plant cell. The presence of altPEP causes the amount of said protein in the treated plant cell to be lower than that in an untreated plant cell.

[0442] In one embodiment, the invention relates to the method as described above, wherein said altPEP is produced outside of said plant cell before being introduced into said plant cell.

[0443] In one embodiment, the invention relates to the method as described above, wherein said altPEP is a synthetic peptide.

[0444] In one embodiment, the invention relates to the method as described above, wherein said altPEP is an isolated peptide.

[0445] In one embodiment, the invention relates to the method as described above, wherein said altPEP is a recombinant peptide. In one embodiment, the invention relates to the method as described above, wherein said altPEP is a hydrophobic peptide or a hydrophilic peptide.

[0446] In one embodiment, the invention relates to the method as described above, wherein said altPEP is introduced into said plant cell in the form of a nucleic acid encoding said altPEP. In particular, the invention relates to the method as described above, wherein said altPEP is introduced into said plant cell in the form of a nucleic acid encoding said altPEP and comprising the means for expressing it.

[0447] In one embodiment, the invention relates to the method as described above, wherein said protein is naturally present in said plant cell.

[0448] In one embodiment, the invention relates to the method as described above, wherein said protein is not naturally present in said plant cell. In particular, the invention relates to the method as described above, wherein said protein is encoded by a transgene artificially introduced into said plant cell. In particular, the invention relates to the method as described above, wherein said protein is encoded by a vector artificially introduced into said plant cell.

[0449] In one embodiment, the invention relates to the method as described above, in which the accumulation of said protein is determined via the implementation of a technique chosen from: Western blot, measurement of enzymatic activity, mass spectrometry and translational fusion. In particular, the invention relates to the method as described above, in which the accumulation of said protein is determined via the implementation of a Western blot.

[0450] In one embodiment, the invention relates to the method as described above, wherein said altPEP has a size of 4 to 41 amino acids, 5 to 40 amino acids, 7 to 20 amino acids or more particularly a size of 8 to 15 amino acids. In particular, said altPEP has a size of 4, 5, 6, 7, 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, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61 , 62, 63, 64, 65, 66, 67, 68, 69 or 70 amino acids.

[0451] In one embodiment, the invention relates to the procedure as previously described, wherein said plant cell or said plant belongs to a plant species selected from: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmericula, Amaranthus tuberus, Arabidhus Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rapeseed), Brassica oleracea, Brassica rapa (rapeseed), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eut. Gossypium raimondii, Gossypium spp. (cotton), Hordeum vulgare (barley), Lollium spp., Lotus japonicus (lotier), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tabac), Oryza sativa (riz), Pisum sativum (pois), Raphanus sativus, Solanum lycopersicum (tomate), Solanum melongena (aubergine), Solanum tuberosum (pomme de terre), Thellungiella halophila, Theobroma cacao, Triticum spp. (blé), Vitis vinifera (vines) and Zea mays (maize).

[0452] In particular, the invention concerns the procedure described above, in which the most vegetal cells are the cells of another.

[0453] In one embodiment, the invention relates to the method as described above, wherein said protein is encoded by a gene selected from: Aae15, Aae16, abcg11, Abdcg34, Acc1, Agb1, Als, Anac076, Apg9, Aribl, Arr1, Arr5, Arr6, At59, Bak1, Bccpl, Bccp2, Bri1, Bzo2h3, Cesaô, Cipk3, Cks1, Cobl8, Coi1, Cpk3, Crk34, Cyp705a18, Cyp71b26, Cyp78a8, Cyp97b3, Dell, Dur3, Ein2, Emb175, Emb2726, Emb9, Epsps, Fnr1, Eve, Ga2ox7, Gapc, Gcn2, Gdi2, G / n2, Gs / 3, Hag5, Hda18, Hexol, Hppd, Hsl1, Iaa31, Iqd28, Jac1, Jar1, Kp1, Lrx2, Mapkkk3, Mapkkkô, Mfp2, Mrb1, Nsp1, Pds, Pen3, Phyb, Pif 3, Pizza, Ppoxl, Ppox2, Prp39, PsbA, Pskrl, Rd21, Ringl, Rosi, Rpt4a, Sfr6, Shr, Shy2, Ski, Sps1, Spt, Stn8, Tap46, Toppô, TubB6, TubB8, Ubala, \ / im3, Sgr1, Abi5, Hsp101, RhIO and Wus.

[0454] In one embodiment, the invention relates to the method as described above, in which said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385.

[0455] In one embodiment, the invention relates to the method as described above, wherein said protein is encoded by an ORF comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0456] In particular, the invention relates to the method as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the method as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention relates to the method as described above, in which said protein is encoded by a gene comprising a nucleic acid sequence having at least 80% identity, preferably at least 90% identity, with a sequence chosen from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0457] In one embodiment, the invention relates to the method as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 1 to 161 and 381 to 385. In one embodiment, the invention also relates to the method as described above, wherein said protein is encoded by a gene comprising a nucleic acid sequence selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3), SEQ ID NOs: 61 to 79 (Dell) and SEQ ID NOs: 109 to 134 (Nsp1).

[0458] In particular, the invention relates to the method as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 26 to 55 (Cpk3). In particular, the invention relates to the method as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 61 to 79 (Dell). In particular, the invention relates to the method as described above, wherein said protein is encoded by a gene comprising one selected from the sequences: SEQ ID NOs: 109 to 134 (Nsp1).

[0459] In another embodiment, the invention relates to the method as described above, wherein said altPEP is chosen from the sequences: SEQ ID NOs: 224 to 366.

[0460] In another embodiment, the invention relates to the method as described above, wherein said protein is involved in at least one plant phenotype selected from: size, shape, surface area, volume, mass and number of leaves; size, shape, surface area, volume, mass and number of flowers; size of the stem (or floral stalk); root biomass; number, length and branching level of the roots; earliness of germination; earliness of budding; earliness of floral induction (or floral transition); germination vigor and duration of juvenile phase; duration of flowering; resistance to biotic stress; resistance to abiotic stress; and number of cells.

[0461] In one embodiment, the invention relates to the method as described above, wherein the introduction of said altPEP results in early bolting in said plant.

[0462] In one embodiment, the invention relates to the method as described above, wherein the introduction of said altPEP results in precocity of flowering in said plant.

[0463] In one embodiment, the invention relates to the method as described above, wherein the introduction of said altPEP results in an increase in stem size in said plant.

[0464] In one embodiment, the invention relates to the method as described above, wherein the introduction of said altPEP results in earliness of stem growth in said plant.

[0465] The inventors have indeed unexpectedly observed that it is possible to directly apply an altPEP to the plant, e.g. via the use of the composition of the invention (see above) comprising an altPEP, to modulate the accumulation of a target protein in the plant, which indicates that the altPEP is taken up by the plant.

[0466] Therefore, in one embodiment, the invention relates to the method as described above, in which said altPEP is introduced into said plant: by watering, by spraying or by adding a fertilizer, a potting soil, a growing substrate or a support in contact with the plant, said altPEP being in particular administered to the plant in the form of a composition comprising 10' 9 M to IO' 4M of said altPEP; by watering, by soaking, by spraying or by adding a fertilizer, a potting soil, a growing substrate or a support in contact with the plant, said altPEP being in particular administered to a seed or a seed in the form of a composition comprising 10' 9 M to 10' 4 M of said altPEP; or by means of a nucleic acid encoding said altPEP and comprising the means for expressing said altPEP, said nucleic acid being artificially introduced into the plant.

[0467] In one embodiment, the invention relates to the method as defined above, in which said altPEP is artificially introduced externally into the plant, preferably by watering, by spraying or by adding a fertilizer, a potting soil, a growing substrate or an inert support.

[0468] In one embodiment, the invention relates to the method as defined above, in which said altPEP is introduced by watering.

[0469] In one embodiment, the invention relates to the method as defined above, in which said altPEP is introduced by spraying.

[0470] In one embodiment, the invention relates to the method as defined above, in which said altPEP is introduced by the addition of a fertilizer.

[0471] In one embodiment, the invention relates to the method as defined above, in which the plant is treated with a composition comprising 10' 9 M to 10' 4 M of said altPEP, or including in particular 10' 9 M, 10' 8 M, 10' 7 M, 10' 6 M, 10' 5 M or 10' 4 M of said altPEP. Preferably, the compositions have a concentration of 10' 8 M to 10' 5M for application by watering or spraying on the plant.

[0472] In a complementary manner, more or less concentrated compositions can be considered to treat the plant with altPEP. For example, and in a non-limiting manner, more concentrated compositions comprising 10' 1 M to 10' 3 M, or including in particular 10' 2 M of altPEP, can be used in the case where the artificially introduced altPEP externally is administered to the plant by spreading.

[0473] In another aspect, the above invention relates to a modified plant containing an altPEP, which "modified plant" corresponds to a plant into which an altPEP has been artificially introduced, in particular by watering, by spraying or via a fertilizer.

[0474] In one embodiment, the invention relates to the modified plant comprising an exogenously introduced altPEP, said altPEP having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said altPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0475] In one embodiment, the invention relates to the modified plant as described above, wherein said fragment comprises: an initiator codon encoding an initiator methionine; and a STOP codon selected from the codons: UAG, UGA and UAA, and said fragment being selected from an open reading frame shifted by one or two nucleotides relative to that encoding said protein.

[0476] In one embodiment, the invention relates to the modified plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the modified plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the modified plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the modified plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0477] In a way of realization, the invention concerns the modified plant described previously, with plants belonging to a selected plant species: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis halleri, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rape), Brassica oleracea, Brassica rapa (rape), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eutrema salsugineum, Glycine max (soya), Gossypium raimondii, Gossypium spp. (coton), Hordeum vulgare (orge), Lollium spp., Lotus japonicus (lotier), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tabac), Oryza sativa (riz), Pisum sativum (pois), Raphanus sativus, Solanum lycopersicum (tomate), Solanum melongena (aubergine), Solanum tuberosum (pomme de terre), Thellungiella halophila, Theobroma cacao, Triticum spp.(wheat), Vitis vinifera (vine) and Zea mays (corn).

[0478] In another aspect, the above invention relates to a transgenic plant comprising a nucleic acid encoding an altPEP and the means for expressing it, said altPEP having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said altPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

[0479] In one embodiment, the invention relates to the transgenic plant as described above, in which said fragment comprises: an initiator codon coding an initiator methionine; and a STOP codon chosen from the codons: UAG, UGA and UAA, and said fragment being chosen from an open reading frame shifted by one or two nucleotides relative to that coding said protein.

[0480] In one embodiment, the invention relates to the transgenic plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame different from the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In particular, the invention relates to the transgenic plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one nucleotide in 3' (or two nucleotides in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell.In particular, the invention also relates to the transgenic plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by two nucleotides in 3' (or one nucleotide in 5') relative to the open reading frame of the nucleic acid sequence naturally translated in said plant cell. In other words, the invention relates to the transgenic plant as described above, in which the translation of the mRNA fragment is carried out in a reading frame shifted by one (or two nucleotides in 5') or two nucleotides in 3' (or one nucleotide in 5') relative to the initiation codon of the open reading frame of the nucleic acid sequence naturally translated in said plant cell.

[0481] In one embodiment, the invention relates to the transgenic plant as defined above, in which the sequence coding for said altPEP is shorter than the sequence of the mRNA coding for said protein.

[0482] In a way of realization, the invention concerns the transgenic plant as described previously, the plant belonging to a selected plant species: Alopecurus myosuroides, Amaranthus hypochondriacus, Amaranthus palmeri, Amaranthus tuberculatus, Arabidopsis halleri, Arabidopsis lyrata, Arabidopsis lyrata, Arabidopsis thaliana, Barbarea vulgaris, Boechera stricta, Brachypodium distachyon, Brassica napus (rape), Brassica oleracea, Brassica rapa (rape), Camelina sativa, Capsella grandiflora, Capsella rubella, Carica papaya, Eutrema salsugineum, Glycine max (soya), Gossypium raimondii, Gossypium spp. (coton), Hordeum vulgare (orge), Lollium spp., Lotus japonicus (lotier), Medicago sativa (luzerne), Medicago truncatula (luzerne), Nicotiana benthamiana (tabac), Oryza sativa (riz), Pisum sativum (pois), Raphanus sativus, Solanum lycopersicum (tomate), Solanum melongena (aubergine), Solanum tuberosum (pomme de terre), Thellungiella halophila, Theobroma cacao, Triticum spp.(wheat), Vitis vinifera (vine) and Zea mays (corn).

[0483] In one embodiment, the invention relates to the transgenic plant as described above, wherein the expression of said altPEP is placed under the control of a strong promoter, preferably a constitutive strong promoter such as the 35S promoter.

[0484] In any respect, it should be noted that the different aspects of invention No. 2, as well as the different embodiments thereof, are interdependent. The latter can therefore be combined with each other to obtain preferred aspects and / or embodiments of invention No. 2 not explicitly described. This is also valid for all the definitions provided in the present description, which applies to all aspects of invention No. 2 and its embodiments. Furthermore, inventions No. 1 and No. 2 are illustrated, without however being limited thereto, by the following Figures and Examples.

[0485] LIST OF FIGURES

[0486] Figure 1

[0487] Figure 1 is a schematic representation illustrating the first steps of the process for preparing and determining a cPEP. In particular, the steps for determining within an mRNA of a protein one of the nucleic acid sequences from which the peptide to be tested (i.e. the potential cPEP) is identified are illustrated.

[0488] The sequences: SEQ ID NOs: 375 to 379 are provided for example purposes only.

[0489] Figure 2

[0490] Identification and characterization of altPEPs

[0491] (a) Schematic representation of a coding gene carrying altORFs producing altPEPs. (b) Distribution of ORF ranking of altPEPs detected by MS. (c) Frequency of altPEPs detected by MS by length ranges, (d) Main root length of A. thaliana seedlings treated with 100 pM peptide for 4 days, (e, f) Quantification of DCL1 expression by RT-qPCR (e) and by Western blot using anti-DCL1 antibodies (f) in A. thaliana leaves treated for 5 days with 100 pM peptide, (g, h) Quantification of COI1, AP2, CPK3 (g) and EIN2 (h) by Western blot using specific antibodies in A. thaliana leaves treated for 5 days with 100 pM peptide.

[0492] Results are representative of four independent experiments. Numbers indicate mean and SEM. Controls are irrelevant peptide and water. Error bars represent SEM, asterisks indicate significant difference between test condition and control according to Student's t-test (d) or Wilcoxon test (eh) (n = 100 (d), n = 4 (eh); p < 0.05).

[0493] Figure 3

[0494] (a) Distribution of altPEPs detected by MS according to the number of Brassicaceae species in which homologs (more than 80) were found, (b) Distribution of altPEPs detected by MS according to their encoding frame, (c) Alignment of homologues of A (SEQ ID NO : 224) in different species of Brassicaceae. (d, e) Conservation of the first altPEP of AP2 (d) and EIN2 (e) in different Brassicaceae species. (f) RefAUG activity of EIN2 compared to altAUGI activity performed with the in vitro transcription / translation system.

[0495] At: Arabidopsis thaliana, Al: Arabidopsis lyrata, Bn: Brassica napus, Bo: Brassica oleracea, Br: Brassica rapa, Bs: Boechera stricta, Cg: Capsella grandiflora, Cr: Capsella rubella, Cs: Camelina sativa, Es: Eutrema salsugineum, The answer.

[0496] Figure 4

[0497] Quantification by qRT PCR of the expression of different genes in response to 100 μM of different peptides

[0498] (a) Treatment of plants with the AtCOI1alt1 peptide; (b) Treatment of plants with the AtAP2alt1 peptide; (c) Treatment of plants with the AtEI N2alt1 peptide (d) Treatment of plants with the AtCPK3alt1 peptide.

[0499] Error bars represent SEM.

[0500] Figure 5

[0501] Complementary peptides increase protein expression

[0502] Analysis of luciferase expression in A. thaliana constitutively expressing the LUC transgene. (a) Agarose gel after PCR amplification of RNA obtained by immunoprecipitation using anti-HA magnetic beads, followed by RT-PCR, on plants treated with the indicated peptide (SC-HA: Scrambled cPEPluc-HA; Luc-HA: cPEPluc-HA). (b) Relative expression of the luciferase transgene in plants treated with the indicated peptide, quantified by RT-qPCR. (ce) Relative quantification of LUC in plants treated with the indicated peptide, (f, g) Ratio between induction and quantification of LUC in plants treated with cPEPluc compared to plants treated with Scrambled cPEPluc, using various peptide concentrations (f) or collected at different time points (g), (h) Transcriptomic analysis of plants treated with cPEPluc-HA compared to plants treated with Scrambled cPEPluc-HA.(i) Proteomic analysis of cPEPluc-HA-treated plants versus Scrambled cPEPluc-HA-treated plants. Protein expression was analyzed by Western blots and quantified with ImageJ.

[0503] Error bars represent SEM, asterisks indicate a significant difference between the test condition and the control according to the Wilcoxon test (a, h, i, n = 5; c, n = 6; b, d- g, n = 12; p < 0.05). Figure 6

[0504] cPEPs require sequence complementarity with their target for activity

[0505] (a) FRET-FLIM analysis of the interaction between cPEPnsp1-FAM and NSP1 (left) or NSPIAcPEP (right) in planta, (b) qRT-PCR quantification of NSP1 expression in M. truncatula roots treated with cPEPnspl or Scrambled cPEPnspl. (c) GUS quantification of peptide-treated M. truncatula roots carrying the Pro NSP1-NSP1-GUS fusion. (d, e) Quantification of NSP1 expression in N. benthamiana leaves after infiltration of different constructs: Wild type i.e. version of NSP1 in which the cPEP sequence has been deleted (NSP1 AcPEP) or version of NSP1 in which the cPEP sequence has been replaced by an artificial sequence (NSP1 AcPEP- cPEPPartificiel), with an empty vector (control) or cPEPnspl or cPEPPartificiel. (f, g) Lateral root formation of M. truncatula WT, nsp1 or NSP1 overexpressing seedlings, in response to cPEPnspl or Scrambled cPEPnspl. (h, i) Quantification of nodules on M. truncatula roots.truncatula seedlings treated with an irrelevant peptide or cPEPskl. (j) Root development of M. truncatula seedlings infected with A. euteiches and treated with an irrelevant peptide or with cPEPrhIO. (k) Relative expression of A. euteiches α-tubulin in M. truncatula seedlings infected with A. euteiches and treated with an irrelevant peptide or with cPEPrhIO.

[0506] Error bars represent SEM, asterisks indicate a significant difference between the test condition and the control according to Student's t-test (fi, j) or Wilcoxon test (be, k) (be, k, n = 6; fi, n = 50; j, n = 60; p < 0.05).

[0507] Figure 7

[0508] cPEPs can modulate A. thaliana development and its response to stress

[0509] (a, b) Primary root length of A. thaliana seedlings treated with Scrambled cPEPdcll or with cPEPdcll. (c) Relative chlorophyll content of A. thaliana seedlings treated with the corresponding peptide, (d) Growth recovery of A. thaliana seedlings after a 45°C heat shock for 45 min and treated with the corresponding peptide, (e) Relative lesion area of ​​A. thaliana seedlings infected with B. cinerea and treated with the indicated peptide, (f) Flowering day measurement of A. thaliana seedlings treated with the indicated peptides, (g, h) Flowering day measurement of A. thaliana seedlings treated with an irrelevant peptide or a mixture of cPEPs (targeting EIN2, BRI1, BAK1 and WUS). (i, j) Leaf area of ​​A. thaliana plants treated with an irrelevant peptide or a mixture of cPEPs (targeting EIN2, BRI1, BAK1 and WUS).Error bars represent SEM, asterisks indicate a significant difference between the tested condition and the control according to Student's t-test (b, c, e, f, h, j) (b, n = 50; c, e, f, h, j, n = 40; d, n = 5; p < 0.05).

[0510] Figure 8

[0511] cPEPs can modulate A. thaliana development and its stress response (a) Quantification of CPK3 expression, using CPK3 antibodies, in peptide-treated A. thaliana plants, (bc) Infection assay of peptide-treated A. thaliana leaves inoculated with B. cinerea spores.

[0512] Error bars represent SEM, asterisks indicate significant difference between test condition and control according to Wilcoxon test (a) and Student's t test (c) (a: n = 6; c, n = 50; p < 0.05).

[0513] Figure 9

[0514] cPEPs increase protein translation

[0515] (a) Luciferase activity analysis in Ae thaliana plants constitutively expressing the LUC transgene and treated with Scrambled cPEPluc or cPEPluc, with or without cycloheximide. (b) Luciferase activity analysis after in vitro transcription / translation of luciferase expressed with cPEPluc or Scrambled cPEPluc.

[0516] Error bars represent SEM, asterisks indicate significant difference between test condition and control according to Wilcoxon test (ab) (a, b, n = 6; p < 0.05).

[0517] Figure 10

[0518] cPEPs are useful tools in agronomy

[0519] (a, b) Relative lesion area on S. lycopersicum leaves infected with B. cinerea and treated with an irrelevant peptide or cPEPjar1. (c, d) Heat stress resistance of soybean plants treated with an irrelevant peptide or cPEPhsp101. (e, f) Growth (plant height) of soybean plants treated with an irrelevant peptide or a mixture of cPEPs (targeting MRB1, SHY2, and SGR1). (g, h) Leaf area of ​​B. vulgaris plants treated with an irrelevant peptide or a mixture of cPEPs (targeting EIN2, BRI1, BAK1, and WUS). (i, j) Leaf area of ​​Ae hypochondriacus plants treated with an irrelevant peptide or a mixture of cPEPs (targeting E1N2, BRI1, BAK1, and WUS).

[0520] Error bars represent SEM, asterisks indicate a significant difference between the test condition and the control according to Student's t-test (b, d, f, h, j, n = 40; p < 0.05). EXAMPLES

[0521] MATERIALS & METHODS

[0522] Biological material and growth conditions

[0523] Medicago truncatula Gaertn cv. Jemalong genotype A17 plants were grown on Long Aston medium as described in Delaux PM et al. (New Phytol. 2013 Jul;199(1):59-65). Arabidopsis thaliana Col-0 plants were grown in soil until 4 weeks of age in a growth chamber (22 / 20°C, 16 h / 8 h L / D, 80% RH, ~75 pmol. m' 2 s ' 1). Barbarea vulgaris seeds were stratified for 24 h at 4°C before being grown in pots in a growth chamber. Amaranthus hypochondriacus, Glycine max and Solanum lycopersicum seeds were sown in pots and grown in a growth chamber. Nicotiana benthamiana and M. truncatula plants were grown as described in Combier JP et al. (Genes and Development. 22, 1549-1559, 2008). ABRE-LUC seedlings were provided by MR Knight (Arabidopsis. Plant Cell. 23, 4079-95, 2011). Arabidopsis thaliana LUC plants were sterilized and sown on 96-well plates containing 100 μL of MS / 2 medium.

[0524] Peptides

[0525] Peptides with sequences SEQ ID NOs: 162 to 223 and 386 to 418 were synthesized by Smart Biosciences and dissolved at a concentration of 2 to 10 mM in water, aliquoted and stored at -80°C.

[0526] Plasmid constructs

[0527] Plasmids were obtained using the Golden Gate cloning strategy in modified pCAMBIA220. The translational fusion Mt-NSP1 (Medtr8g020840):GUS was performed using 3183 bp of the NSP1 promoter and 3180 bp of the post CDS section of NSP1. Expression in N. benthamiana leaves was performed using the 35S promoter.

[0528] Plant transformation

[0529] The transformations of the leaves of Nicotiana benthamiana were carried out according to Combier

[0530] JP et al. (Genes and Development. 22, 1549-1559, 2008).

[0531] Gene expression analysis

[0532] Quantification of mRNAs was performed by qRT-PCR using the appropriate primer pairs chosen from the sequences: SEQ ID NOs: 367 to 374. Expression levels for controls were set to 100. The primers used for tests on A. euteiches are described in Camborde et al. (New Phytol. 233:2232-2248. 2022).

[0533] Pathogenicity tests

[0534] Leaves of wild-type or mutant A thaliana were sprayed daily with 100 μM of peptide or 100 μM of the corresponding scramble version for 3 days. Six hours after the last treatment, five mature leaves per plant were inoculated with a 5 μL droplet of 2.5x10 5spores / mL of Botrytis cinerea strain B05.10 diluted in 100 pM peptide or its corresponding scramble version. After inoculation, plants were kept at 100% relative humidity. Then, a 2 pL droplet of 100 pM peptide or 100 pM of the corresponding scramble version was deposited daily on B. cinerea-infected leaves for 3 days (until symptoms appeared). Leaves were removed from the plants to determine lesion areas using the ImageJ program. For tomato, the protocol was the same except that inoculation was performed with 5,000 B. cinerea spores, without peptide. Peptides were added 1 h after inoculation (1 pL of 500 pM) and daily for two days with 5 pL of 100 pM peptide. For infection of M. truncatula with A.euteiches, plants were grown on agar medium and treated with 10 μL of 100 μM peptides, 24 h before, and 24 h and 72 h after infection with 10 μL (1000 spores) of A. euteiches spores. Plants were harvested 7 days after inoculation for RNA extraction.

[0535] Treatments with cPEPs

[0536] N. benthamiana plants were sprayed with leaves 24 h before harvest. For Luc assays, 100 μL of MS / 2 liquid medium containing the peptides was added to each well. 5 μL of luciferin was added, and luciferase activity was read 30 min later using a spectrophotometer. All other assays were performed by spraying or watering the plants. To quantify the cPEP-induced protein level in Arabidopsis, rosettes were sprayed daily with 100 μM of peptide or its control for 5 days. Leaves were harvested 6 h after the last treatment for Western blot analyses. For flowering assay and chlorophyll content, 10-day-old Arabidopsis plants were sprayed with 500 μL of 10 μM peptide three times a week until flowering. Chlorophyll content was measured with SPAD chlorophyll meter (Konica Minolta).Leaf area was measured using ImageJ software. Barbarea vulgaris and A. hypochondriacus seedlings were treated immediately after sowing and 3 times per week with 500 μL of a 20 μM mixture of each peptide. For Western blotting, heat shock was performed by placing 20-day-old seedlings grown in 24-well plates on MS / 2 for 90 min at 37 °C before harvesting. The seedlings were treated with 100 μM peptide for 24 h. For the heat shock resistance test on A. thaliana, 3-day-old seedlings were treated for three days with 100 μM peptide before placing the plants at 45 °C for 45 min. The seedlings were placed in a growth chamber to recover and treated 24 h after heat shock with 100 μM peptide. For heat shock of soybean, one-week-old seedlings were treated for 48 h, 24 h, and 30 min before being placed at 45 °C for 24 h.For soybean growth, young plants were treated 3 times per week for two weeks with 500 μL of 100 μM peptides.

[0537] Protein extraction and Western blot analysis

[0538] Total proteins from Arabidopsis plants were extracted according to Ormancey et al. (Plant Sci. 2019 Mar;280:12-17). Western blot analyses were performed according to Combier et al. (Genes Dev. 2008 Jun 1;22(11):1549-59). Protein levels were normalized to Ponceau staining. Antibodies were purchased from Agrisera and Sigma.

[0539] In vitro transcription / translation

[0540] The T nT® SP6 High Yield Wheat Germ Protein Expression System (Promega) was used according to the manufacturer's instructions. The LUC sequence was amplified using GoTaq® Polymerase (Promega), and cPEPs or their corresponding Scramble versions were added just before the start of the reaction. The reaction was stopped after 60 min, after which LUC activity was measured with a plate spectrophotometer (Perkin-Elmer Victor Nivo).

[0541] Treatment at

[0542] Arabidopsis thaliana plants containing the LUC construct were treated by infiltrating the leaves with a peptide solution with or without cycloheximide (200 pg.rnL' 1 ) in MS / 2 medium, 24 h before harvest for the LUC test.

[0543] RNA co-immunoprecipitation was adapted from Merret et al. (Plant Physiol. 174:1216-1225. 2017). 400 mg of tissue powder was incubated in 3 mL of lysis buffer (200 mM Tris, pH 9.0, 110 mM potassium acetate, 0.5% Triton X-100, 0.1% Tween® 20, 5 mM DTT, 1.5% protease inhibitor, and 80 units mL-1 RNasin). The lysate was incubated on ice for 10 minutes, then centrifuged at 16,000g for 10 minutes at 4°C. 1.5 mL of crude extract was incubated with 25 μL of anti-HA magnetic beads (Thermo Scientific) for 1.5 h at 4°C under rotation. After binding, the beads were washed five times with 0.75 mL of lysis buffer. Elution was performed with 200 μL of 8 M guanidium for 5 min on ice and precipitated overnight with 300 μL of 100% ethanol.After centrifugation (16,000g, 45 min, 4°C), pellets were resuspended in 200 μL of Monarch DNA / RNA Protection Reagent (New England Biolabs) and RNA was extracted according to the manufacturer's instructions and concentrated to 10 μL using the Monarch® RNA Cleanup Kit (New England Biolabs). 300 μL of input and unbound fractions were retained and RNA was extracted as described above. Reverse transcription was performed on 10 μL of eluate or 500 ng of input / unbound using the Superscript® IV Kit (Thermo Scientific). PCR amplification was performed on 1 μL of cDNA with specific primers.

[0544] FRET FLIM analysis, foil sample preparation for testing

[0545] Samples were prepared based on the protocols of Camborde et al (Nat Protoc. 12:1933-1950. 2017). Briefly, Agrobacterium tumefaciens strain GV3101 pmp90 carrying plasmids 35S-NSP1 or 35S-NSP1AORF were used to infiltrate N. benthamiana leaves. Agro-infiltrated discs from at least three different leaves were fixed after 48 hours by vacuum infiltration of a 4% (w / v) paraformaldehyde fixation solution, followed by a permeabilization step using proteinase K treatment. After washes, nucleic acid staining was performed by vacuum infiltration of a 5pM Sytox Orange solution (Invitrogen). Then, the disks were washed and mounted on TBS before FLIM measurements of the nuclei.

[0546] FRET FLIM analysis, preparation of cPEP sheet samples for FRET-FLIM experiments

[0547] Plasmids 35s-NSP1 or 35s-NSP1AcPEP were transformed into A. tumefaciens strain pmp90 GV3101 and agro-infiltrated into N. benthamiana leaves. 40h later, a 10pM solution of cPEP-FAM was infiltrated into the same leaves and the plants were incubated for 3h. Then, leaf discs were fixed and treated as described in Camborde et al (Nat Protoc. 12:1933-1950. 2017), then washed and mounted on TBS before cytoplasmic FLIM measurements.

[0548] FRET FLIM analysis, TCSPC-FLIM data acquisition

[0549] FLIM was performed on a Leica TCS SP8 SMD which consists of a LEICA DMi8 inverted microscope equipped with a PicoQuant TCSPC system. FITC donor excitation at 470 nm was performed by a picosecond pulsed diode laser at a repetition rate of 40 MHz, through an oil immersion objective (63*, NA 1.4). The emitted light was detected by a Leica HyD detector in the emission range of 500-550 nm. Images were acquired with acquisition photons up to 1500 per pixel. FRET FLIM analysis, FLIM data analysis

[0550] From the fluorescence intensity images, decay curves were calculated per pixel and fitted (by maximum likelihood estimation of the Poisson distribution) with a mono- or double-exponential decay model using SymphoTime 64 software (PicoQuant, Germany). The mono-exponential model function was applied for donor samples with only FITC present. The double-exponential model function was used for samples containing FITC and Sytox. The experiments were repeated at least three times to obtain statistically valid data. The energy transfer efficiency (E) based on the fluorescence lifetime (T) was calculated as follows: E = 1 - (TD+A / TD-A), where TD+A is the fluorescence lifetime of the donor in the presence of the acceptor and TD-A is the fluorescence lifetime of the donor in the absence of the acceptor.

[0551] Statistical analyses

[0552] Mean values ​​of relative gene expression, protein level, or phenotypic parameters were compared using the Wilcoxon test or Student's t test. Error bars represent the standard error of the mean (SEM). Asterisks indicate significant differences (p < 0.05).

[0553] RESULTS

[0554] AltPEPs control the translation of their coding gene

[0555] A first objective was to examine whether natural altPEPs could be detected in A. thaliana (Fig. 2a). To this end, a list of all potential altORFs longer than 10 amino acids and located out-of-frame in the coding sequences of A. thaliana was bioinformatically generated. Based on this list, we analyzed a recently published MS dataset (Müller JB et al. Nature. 582, 592-596 (2020)) and identified 112 novel altPEPs, showing that altPEPs are naturally represented in the in planta proteome (SEQ ID NOs: 252-363). At the same time, 85 of the 112 corresponding reference proteins were identified in the same dataset, suggesting that altPEPs might in some cases be more highly expressed than their reference proteins. Among the 112 altPEPs identified, 24 of them corresponded to the first altORF found in the coding sequence (Fig.2b; SEQ ID NOs: 258, 261, 262, 263, 270, 274, 284, 285, 286, 290, 295, 303, 312, 316, 320, 321, 323, 324, 332, 343, 344, 352, 353 and 358). Surprisingly, the majority of the identified altPEPs were encoded from other alternative AUGs (altAUGs), from the second to the 23rd. ème, showing that several altAUGs, located downstream of canonical AUGs, can be translated and be active in planta (Fig. 2b). The average length of the peptides encoded by the detected altORFs was 45 amino acids, while the longest contained 212 amino acids (Fig. 2c, SEQ ID NO: 295). Interestingly, 35 altPEPs did not share any homology among Brassicaceae (Fig. 3a). Finally, it is surprising that 105 out of 112 altPEPs are encoded by altAUGs located in frame 2 (considering that the main protein is encoded by frame 1) (Fig. 3b). These altPEPs have not been described by others (Wang S. et al. Mol Plant 13, 1-16 (2020)), providing additional translated peptides to those already described.This analysis showed that altPEPs are naturally expressed at detectable levels in planta, and are likely widespread among the various annotated coding genes, although the altPEPs identified here likely represent only a fraction of the altPEPs actually present in plant cells.

[0556] To investigate the biological roles of altPEPs, two types of altPEPs were studied: one well conserved among Brassicaceae, and corresponding to altORF 8 of the DCL1 gene (Fig. 3c), and another, corresponding to the first altORF of the COI1 gene, but not conserved among Brassicaceae. Ae thaliana seedlings were treated with the AtDCLI ait 18 peptide (SEQ ID NO: 224) and root development analyzed, since dcl1 mutants exhibit longer main roots (Park, W., et al. Curr. Biol. 12, 1484-1495 (2002)). Interestingly, treatment with the AtDCLI alt18 peptide led to a decrease in root development (Fig. 2d). qRT-PCR and Western blot analysis to quantify DCL1 expression was performed and while no effect on mRNA expression was observed, application of the AtDCLI alt18 peptide increased DCL1 protein accumulation (Fig. 2e, f).Interestingly, treatment of plants with the AtCOI1alt1 peptide revealed an increase in the level of COI1 protein, showing that this property is not limited to DCL1 (Fig. 2g; Fig. 4a).

[0557] To extend this observation, the first altPEPs of more than 10 amino acids in several well-known coding genes of A. thaliana were identified by bioinformatics. These are the three genes: AP2 and EIN2, for which the first potential altPEP was conserved among Brassicaceae (Fig. 3d, e), and CPK3, for which the first altPEP was not conserved. It was also tested whether the altAUG 1 of the EIN2 gene is translated in vitro, using an in vitro transcription / translation system in wheat germ extracts. For this, the luciferase CDS was fused to the 5'UTR of EIN2 up to the refAUG or altAUGI , and the luciferase expression was compared. Interestingly, it was shown that altAUGI is effective in promoting translation (Fig. 3f). Translation efficiency is of the same order as refAUG activity, suggesting co-translation in similar amounts of canonical EIN2 protein and altPEP.Plants were then treated with the three synthetic altPEPs (AtAP2alt1; SEQ ID NO: 243, AtCPK3alt1 and AtEIN2alt1; SEQ ID NO: 241). In each case, an increase in the reference protein was observed, without detecting any change in mRNA expression (Fig. 2g, h; Fig. 4b, c, d). This suggests that the increase in reference protein expression is likely a common property of altPEPs. In parallel, the conservation of altPEPs does not appear to be important for their activity. Based on these two findings, three altPEPs (SEQ ID NOs: 334 to 366) corresponding to different regions of the EIN2 gene were synthesized and A. thaliana plants were independently treated with them. Interestingly, all three peptides were able to increase the level of EIN2 protein (Fig. 2h), showing that all altPEPs tested share the property of increasing the levels of their reference protein.

[0558] Complementary Peptides or cPEPs

[0559] It was demonstrated in the previous point that short peptides can physically interact with their nascent RNA (Lauressergues D, et al. Cell Reports. 38:110339, 2022). It was questioned whether any peptide translated from a sequence located in a coding gene could share the same property (Fig. 5a). To do this, a complementary peptide of 10 amino acids (SEQ ID NO: 213) was designed corresponding to a 10 amino acid fragment of the luciferase protein, constitutively expressed in Arabidopsis thaliana (Whalley et al. Plant Cell. 23, 4079-95, 2011), and showing no homology with any sequence in the A. thaliana genome.Using RNA-IP followed by PCR on plants treated with HA-tagged peptides (cPEPluc-HA; SEQ ID NO: 387), it was validated that such a cPEP was specifically able to interact with luciferase mRNA, whereas a corresponding Scrambled peptide (SEQ ID NO: 386) could not (Fig. 5a). To determine whether this interaction could have biological relevance, plants were treated with the synthetic cPEPluc and luciferase expression was analyzed. While qPCR analysis showed no effect on mRNA abundance (Fig. 5b), treatment with the peptide increased luciferase activity compared to treatments with water or non-luciferase-specific peptides (Fig. 5c). A 96-well microplate assay was developed, in which seeds were sown on half-solid MS medium and 14-day-old seedlings were treated by adding 100 μL of liquid medium containing the peptides.In a second step, ten additional 10-amino acid peptides targeting distinct sequences of the luciferase gene were developed (SEQ ID NOs: 388 to 397), in all three frames (ORF1 corresponds to the canonical luciferase protein), and all were able to increase luciferase activity (Fig. 5d). In parallel, 7 cPEPs of 5 to 60 amino acids (SEQ ID NOs: 398 to 403) were designed and synthesized. Exogenous treatment with these different peptides revealed an increase in luciferase activity for peptides ranging from 5 to 40 amino acids, whereas longer peptides had no effect (Fig. 5e). The effect of peptide concentration and treatment time on cPEPluc activity was then analyzed. Thus, the optimal concentration of cPEP under these conditions was found to be 50 pM (Fig. 5f), and 24h of treatment showed the maximal effect of cPEP (Fig. 5g).Finally, to investigate whether cPEPs could have side effects, A thaliana plants expressing luciferase were treated with cPEPluc (SEQ ID NO: 213) or its Scrambled peptide (SEQ ID NO: 220) and transcriptomic and proteomic analysis was performed (Fig. 5h, i). Interestingly, no changes in the transcriptome and proteome of cPEPluc-treated plants were detected, compared to Scrambled peptide-treated plants, suggesting a high specificity of cPEPs for their target protein.

[0560] Generalization of the concept of peptides increasing protein expression

[0561] To test whether cPEPs can target any protein, the activity of 12 cPEPs targeting 12 different proteins for which antibodies were available was investigated and validated in three different plant species. The question was whether the increase in protein levels observed after cPEP treatment was sufficient to modulate plant development. To address this question, the development focused on different proteins in the model plant M. truncatula. Application of cPEPnspl (SEQ ID NO: 164) decreased the amount of lateral roots (Fig. 6f, g), as did the nsp1 mutant and an overexpression of NSP1, while both remained insensitive to the peptide (Fig. 6g). The Sickle (SKL) gene of M. truncatula is homologous to AtEIN2, and ski mutants develop more nodules than wild-type plants (Penmetsa et al. Plant J. 55:580-595, 2008).Consistently, application of a cPEPskl (SEQ ID NO: 411) led to a decrease in the amount of nodules (Fig. 6h, i). It was then targeted the RH 10 protein of M. truncatula, which modulates plant response to a pathogenic oomycete, Aphanomyces euteiches (Camborde et al. New Phytol. 233:2232-2248. 2022). Treatment of plants with a cPEP targeting MtRH10 (SEQ ID NO: 412) increased plant resistance to the pathogen, as revealed by increased root development and decreased expression of A euteiches α-tubulin in roots (Fig. 6j, k).

[0562] Generalization to other plant models, other proteins

[0563] The work then focused on different A. thaliana proteins involved in different plant functions. First, the treatment of A. thaliana seedlings thaliana with a cPEPdcll (SEQ ID NO: 163) led to a decrease in primary root growth since dcl1 mutants exhibit longer primary roots (Park et al. Curr. Biol. 12:1484-1495 (2002). (Fig. 7a, b). Then, A. thaliana plants were treated with cPEPs targeting chlorophyll content regulators. Interestingly, a cPEP targeting the ABI5 protein (SEQ ID NO: 406) could be identified, decreasing chlorophyll content, and a cPEP targeting the SGR1 protein (SEQ ID NO: 407), increasing this content (Fig. 7c). Similarly, a cPEP targeting the HSP101 protein (SEQ ID NO: 404), involved in heat stress tolerance (Queitsch et al., Plant Cell. 12:479-492, 2000), improved seedling viability to heat shock (Fig. 7d).In parallel, several Ae thaliana plant defense regulators were targeted, AGB1 (SEQ ID NO: 195), MAPKKK3 (SEQ ID NO: 187), JAR1 (SEQ ID NO: 192), MAPKKK5 (SEQ ID NO: 188), ABCG34 (SEQ ID NO: 194) and CPK3 (SEQ ID NO: 162). Interestingly, these cPEPs improved plant defense against the necrotrophic fungus Botrytis cinerea, as revealed by the decrease in lesion size observed in cPEP-treated plants compared to plants treated with an irrelevant peptide (Fig. 7e; Fig. 8). Then, several cPEPs were designed targeting different proteins involved in plant development by measuring the flowering day.It was possible to identify cPEPs increasing plant development (SHY2 and MRB1, SEQ ID NOs: 178 and 180) while others were able to decrease plant development (BRI1, SEQ ID NO 198; BAK1, SEQ ID NO 199; TAP46, SEQ ID NO 181; SPT, SEQ ID NO 182; EIN2, SEQ ID NO 204; GA2OX7, SEQ ID NO 183; PHYB, SEQ ID NO 184; HAG5, SEQ ID NO 185; SHR, SEQ ID NO 186 and WUS, SEQ ID NO 196) (Fig. 7f). Finally, it was investigated whether cPEPs could have synergistic effects, by mixing some of them. Interestingly, while each peptide separately decreased development by up to 17% (Fig. 7f), a mixture of cPEPs targeting EIN2, BRI1, BAK1 and WUS (respectively SEQ ID NOs: 204, 198, 199 and 196), decreased development by 23%, as shown by flowering day (Fig. 7g, h) and leaf growth (Fig. 7i, j), showing a synergistic effect of cPEPs.All these data showed that, in addition to enhancing protein expression, cPEPs are useful tools to precisely modulate several plant phenotypes.

[0564] cPEPs increase the efficiency of protein translation

[0565] cPEPs increase protein levels without disrupting mRNA levels, suggesting that cPEPs increase protein translation or stability. To distinguish between the two options, A. thaliana plants expressing the LUC gene were treated with cPEPluc (SEQ ID NO: 213) and cycloheximide (CHX), a translation inhibitor. Luciferase activity assay showed that the effect of cPEPluc was inhibited in the presence of CHX, indicating that cPEPs do not affect protein stability (Fig. 9a). To support these data, the LUC gene was expressed with or without cPEPluc in the wheat germ in vitro transcription / translation system, where no protease activity occurs. This revealed that cPEPluc increased LUC activity in vitro, strongly supporting the idea that cPEPs increase protein translation efficiency (Fig. 9b).

[0566] Agronomic interest of cPEPs

[0567] The main interest of cPEPs could be the use in agronomy to improve crop yield. To prove this, they were tested on plants of agronomic interest, focusing on the same phenotypes as those studied in model plants. Thus, the work initially focused on plant defense and the tomato JAR1 protein was targeted. Consistent with the previous observation in A. thaliana, treatment of tomato with cPEPjarl (SEQ ID NO: 413) improved the plant's resistance to B. cinerea (Fig. 10a, b). In parallel, the homolog of HSP101 was identified in soybean and a cPEP targeting this protein was designed (SEQ ID NO: 408). Interestingly, treatment of soybean plants with this peptide increased their tolerance to heat stress (Fig. 10c, d).In parallel, it was validated on soybean that the use of cPEPs can improve plant growth, using a mixture of cPEPs targeting SHY2, MRB1 and SGR1 (respectively SEQ ID NOs: 410, 409 and 407) (Fig. 10e, f). Finally, it was tested whether cPEPs could decrease weed growth by targeting a Brassicaceae species, Barbarea vulgaris, and it was shown that a mixture of cPEPs targeting EIN2, BRI1, BAK1 and WUS (respectively SEQ ID NOs: 417, 415, 414 and 416), was able to do so (Fig. 10g, h). To go further, one of the most invasive and problematic weeds, Amaranthus, was selected and cPEPs were designed to target the corresponding proteins (respectively SEQ ID NOs: 204, 176, 177 and 196). A mixture of these cPEPs was able to decrease the plant growth (Fig. 10i, j).

[0568] Conclusion

[0569] The results presented demonstrated the possibility of modulating the expression of any coding gene by external application of small synthetic peptides, thus facilitating the study of genes without the need for transgenic plants. This may be particularly relevant in the case of plants recalcitrant to genetic transformation. Simply watering or spraying plants with cPEPs allows a biological response consistent with what is known about the function of the targeted proteins, such as modulating plant growth or improving plant resistance to certain pathogens.

[0570] Agriculture in the 21st century faces several major challenges in feeding the growing world population. In this context, there is an urgent need to find new molecules to maintain or improve crop yields. To date, no credible alternative to chemicals has emerged. The use of CRISPR in agriculture is promising, particularly for improving crop growth, but it is difficult to imagine weed control with this strategy. The use of small RNAs, despite their fantastic potential, faces the intractable problem of poor penetration into plant cells, leading to limited activity in the field, except for insect control.In parallel, it has been shown here that cPEPs are able to modulate different plant traits, such as heat resistance or chlorophyll content, which are very difficult to manage with chemicals or other molecules.

[0571] In this context, the development of cPEP technology opens a new avenue in agriculture with the use of small peptides. In parallel, the mode of action of cPEPs, based on the complementarity of their sequence with the targeted protein, will make it easier to identify non-specific interactions by bioinformatics, which will allow targeting a single species, a family or all plants.

[0572] Finally, because peptides are short polymers of amino acids, they are likely to be rapidly degraded by soil microbiota, unlike polluting chemicals. Furthermore, peptide penetration into animal cells appears difficult without the presence of cell-penetrating peptides, which suggests that cPEPs will have no biological activity in animals and humans, apart from possible intrinsic toxicity.

Claims

CLAIMS A method for preparing and determining a cPEP, said cPEP: having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids; being capable of modulating the accumulation of a protein in a plant cell; and not being capable of modulating the accumulation of the mRNA encoding said protein, said method comprising: a. a step of determining the nucleic acid sequence of the messenger RNA (mRNA) encoding said protein; b. a step of determining within this mRNA the nucleic acid sequence naturally translated in said plant cell and which corresponds to the open reading frame encoding said protein; c.a step of determining within this nucleic acid sequence naturally translated in said plant cell a fragment thereof, said fragment having a size of 3n nucleotides, n being from 4 to 70, in particular n being from 4 to 41, and said fragment having a size smaller than that of the nucleic acid sequence naturally translated in said plant cell; d. a step of producing the peptide encoded by said fragment; and e. a comparison step:. - between the accumulation of said protein in a plant cell in the presence of said peptide and the accumulation of said protein in a plant cell of the same type in the absence of said peptide; and / or - between the phenotype of a plant in the presence of said peptide and the phenotype of a plant of the same type in the absence of said peptide, in which: - a difference in the amount of said protein in the presence of said peptide compared to the amount of said protein in the absence of said peptide; and / or - a difference in the phenotype in the presence of said peptide compared to the phenotype in the absence of said peptide, indicates that said peptide is a cPEP capable of modulating the accumulation of said protein in a plant cell. cPEP, of 4 to 70 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein. Nucleic acid encoding a cPEP according to claim 2.A composition comprising a cPEP as an active ingredient, said cPEP: having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a naturally translated nucleic acid sequence on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA; being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein; and being in particular at a concentration of 5 pM to 500 pM or 30 pM to 70 pM, or being in particular at a concentration of 50 pM. Composition according to claim 4, said composition being a phytopharmaceutical composition, a herbicidal composition or a coating composition, in particular said coating composition further comprising at least one fixing agent.A coated seed comprising a plant seed, said plant seed being coated with a coating composition according to claim 5. Use of a cPEP as a phytosanitary agent for modulating the accumulation of a protein in a plant cell, said cPEP having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of said protein encoded by said mRNA, said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.A method for modulating the accumulation of a protein in a plant cell comprising a step of introducing: a cPEP; or a nucleic acid encoding said cPEP and the means for expressing it, into said plant cell, the introduction of said cPEP resulting in a modulation of the quantity of said protein in said plant cell, said cPEP having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of said protein encoded by said mRNA, said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.A method according to claim 8, said method making it possible to: promote the development of a plant; or to slow down or prevent the development of a plant. A modified plant comprising an exogenously introduced cPEP, said cPEP having a size of from 4 to 70 amino acids, in particular from 4 to 41 amino acids, of which the. amino acid sequence corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated onto an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.Transgenic plant comprising a nucleic acid encoding a cPEP and the means for expressing it, said cPEP having a size of 4 to 70 amino acids, in particular 4 to 41 amino acids, the amino acid sequence of which corresponds to the translation via the genetic code of a fragment of a nucleic acid sequence naturally translated on an mRNA in a plant cell which corresponds to the open reading frame of a protein encoded by said mRNA, said cPEP being capable of modulating the accumulation of said protein in the plant cell and not being capable of modulating the accumulation of the mRNA encoding said protein.

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