Stem rust resistance genes and use thereof

Abstract

The present invention relates to isolated polynucleotides encoding proteins which, when expressed in a Triticeae plant cell, particularly wheat plant cells, enhance tolerance and / or confer resistance towards stem rust disease, and to Triticeae plants comprising the polynucleotides that are tolerant or resistant to the stem rust diseases, as well as to methods of producing same and of identifying resistant plants.

Description

[0001] STEM RUST RESISTANCE GENES AND USE THEREOF

[0002] FIEED OF THE INVENTION

[0003] The present invention relates to isolated polynucleotides encoding proteins which, when expressed in a Triticeae plant cell, particularly wheat plant cells, enhance tolerance and / or confer resistance towards stem rust disease, and to Triticeae plants comprising the polynucleotides that are tolerant or resistant to the stem rust diseases, as well as to methods of producing same and of identifying resistant plants.

[0004] BACKGROUND OF THE INVENTION

[0005] Elongated goatgrass (Aegilops longissima Schweinf. & Muschl.) (AEL) is one of the five species in the section Sitopsis. It has a wide ecological preference, which includes the coastal plains of Egypt, Israel and Lebanon, and sandstone and limestone soils of Jordan (van Slageren M W. 1994, Wild wheats: A monograph of Aegilops L. and Amblyopyrum (Jaub. & Spach) Eig (Poaceae). Wageningen Agric. Univ. Papers, Wageningen, Netherlands). Recent work by Huang S et al (2018, Plant disease, 102(6): 1124-1135) on a diverse collection of Ae. longissima lines revealed that many accessions are highly resistant to inoculation with leaf, stripe, or stem rust pathogens. This finding was in line with previous reports of resistance found in Ae. longissima against stem rust (Anikster et al. 2005, Plant disease, 89(3):303-308; Scott et al. 2014, Plant disease, 98(10): 1309-1320); leaf rust (Anikster et al., 2005 ibid ', stripe rust (Anikster et al., 2005, ibid)', powdery mildew (Ceoloni et al. 1992, Hereditas, 116:239- 245); Septoria blotch (Ecker et al. 1990, Plant Breeding, 104(3):224-230; McKendry and Henke. 1994, Crop Science, 34(4): 1080-1084); and eye spot (Sheng and Murray. 2013, Plant disease, 97(3):346-353; Sheng et al. 2012, Theoretical and Applied Genetics, 125(2):355-366; Sheng et al. 2014, Theoretical and applied genetics, 127(10):2085- 2093). Genetic analysis of the closely related species Aegilops sharonensis demonstrated monogenic inheritance of rust resistance genes (Olivera et al., 2008, Phytopathology 98:353-358).

[0006] The dynamic nature of the pathogenic fungi causing rust diseases requires active efforts for developing new control means. SUMMARY OF THE INVENTION

[0007] The present invention provides isolated polynucleotide molecules encoding products that confer, enhance, or otherwise facilitate the tolerance and / or resistance of Triticeae plants and cultivars comprising these polynucleotides in at least part of the plant cells to rust diseases caused by virulent forms of Puccinia graminis f. sp. tritici, particularly to stem rust disease. In certain aspects, the present invention further provides methods of producing the rust-disease tolerant / resistant Triticeae plant and methods of selecting same. In certain currently exemplary embodiments, the Triticeae plant is wheat.

[0008] The present invention is based in part on the discovery of a novel gene encoding at least one protein product comprising nucleotide binding site-leucine-rich repeat (NNB- LRR) domains. The at least one protein product include short and / or longer versions of the NNB-LRR containing protein which is encoded from respectively short and / or longer coding sequences comprising a common Open Reading Frame (ORF). The gene was expressed in Aegilops longissima plants infected with Puccinia graminis f. sp. tritici, and transient silencing of the gene in these Ae. longissima resistant plants by virus induced gene silencing (VIGS) targeted to an exon in the common ORF resulted in sensitivity to the stem rust P. recondite isolate.

[0009] According to certain aspects, the present invention provides a Triticeae plant comprising at least one cell comprising a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, wherein the heterologous polynucleotide is capable of conferring or enhancing tolerance and / or resistance of the plant to stem rust disease.

[0010] According to certain embodiments, the heterologous polynucleotide encodes at least one polypeptide comprising an amino acid sequence having at least 90% identity to the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NOG.

[0011] According to some embodiments, the encoded polypeptide comprises an amino acid sequence having at least 85%, at least 90%, at least 95%, or at least 99% identity to the amino acids sequence set forth in SEQ ID NO: 1.

[0012] According to certain exemplary embodiments, the encoded polypeptide comprises the amino acid sequence set forth in SEQ ID NO: 1. According to further certain exemplary embodiments, the encoded polypeptide consists essentially of the amino acid sequence set forth in SEQ ID NO: 1.

[0013] According to some embodiments, the encoded polypeptide comprises an amino acid sequence having at least 85%, at least 90%, at least 95%, or at least 99% identity to the amino acids sequence set forth in SEQ ID NO:3.

[0014] According to certain exemplary embodiments, the encoded polypeptide comprises the amino acid sequence set forth in SEQ ID NO: 3. According to further certain exemplary embodiments, the encoded polypeptide consists essentially of the amino acid sequence set forth in SEQ ID NO: 3.

[0015] In some embodiments, the heterologous polynucleotide encodes at least one polypeptide having the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NO:3. Each possibility is a separate embodiment.

[0016] According to certain embodiments, the heterologous polynucleotide comprises a nucleic acid sequence having at least 75% identity to at least one nucleic acid sequence set forth in any one of SEQ ID NO:2 and SEQ ID NO:4 over the entire length of the polynucleotide. Each possibility is a separate embodiment.

[0017] According to certain embodiments, the heterologous polynucleotide comprises a nucleic acid sequence having at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the nucleic acid sequence set forth in SEQ ID NO:2 over the entire length of the polynucleotide.

[0018] According to certain embodiments, the heterologous polynucleotide comprises the nucleic acid sequence set forth in SEQ ID NO:2. According to certain embodiments, the heterologous polynucleotide consists essentially of the nucleic acid sequence set forth in SEQ ID NO:2.

[0019] According to certain embodiments, the heterologous polynucleotide comprises a nucleic acid sequence having at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the nucleic acid sequence set forth in SEQ ID NO:4 over the entire length of the polynucleotide.

[0020] According to certain embodiments, the heterologous polynucleotide comprises the nucleic acid sequence set forth in SEQ ID NO:4. According to certain embodiments, the heterologous polynucleotide consists essentially of the nucleic acid sequence set forth in SEQ ID NO:4.

[0021] According to certain embodiments, the heterologous polynucleotide comprises a nucleic acid sequence having at least 80% identity to the nucleic acid sequence set forth in any one of SEQ ID NO:5 and SEQ ID NO:6. Each possibility is a separate embodiment.

[0022] According to certain embodiments, the heterologous polynucleotide comprises a nucleic acid sequence having at least at least 85%, at least 90%, at least 95%, or at least 99% identity to the nucleic acid sequence set forth in SEQ ID NO:5.

[0023] According to certain embodiments, the heterologous polynucleotide comprises the nucleic acid sequence set forth in SEQ ID NO:5. According to certain embodiments, the heterologous polynucleotide consists essentially of the nucleic acid sequence set forth in SEQ ID NO:5.

[0024] According to certain embodiments, the heterologous polynucleotide comprises a nucleic acid sequence having at least at least 85%, at least 90%, at least 95%, or at least 99% identity to the nucleic acid sequence set forth in SEQ ID NO:6.

[0025] According to certain embodiments, the heterologous polynucleotide comprises the nucleic acid sequence set forth in SEQ ID NO:6. According to certain embodiments, the heterologous polynucleotide consists essentially of the nucleic acid sequence set forth in SEQ ID NO:6.

[0026] Introducing the heterologous polynucleotide capable of enhancing or conferring tolerance and / or resistance to a Triticeae plant towards stem rust disease may be achieved by various means, all of which are explicitly encompassed within the scope of the present invention.

[0027] According to certain embodiments, the heterologous polynucleotide is introduced into the Triticeae plant by means of transformation of said heterologous polynucleotide into at least one cell of the plant. According to certain embodiments, the heterologous polynucleotide is operably linked to at least one regulatory element capable of controlling expression of said polynucleotide in a cell of the plant, thereby forming a DNA construct or an expression vector. The at least one regulatory element can be endogenous or heterologous to the plant cell. According to certain embodiments, the at least one regulatory element is a promoter. According to certain embodiments, the promoter is derived from a Triticeae plant, including, but not limited to, Triticum plant and Aegilops plant. According to certain embodiments, the promoter is the natural / endogenous promoter deriving the expression of the tolerance / resistance conferring gene in Ae. longissima. According to certain additional or alternative embodiments, the promoter is selected from the group consisting of a constitutive, a tissue specific, and a development stage specific promoter. Each possibility is a separate embodiment.

[0028] According to certain currently exemplary embodiment, the constitutive promoter comprises CaMV35S.

[0029] According to certain embodiments, the at least one regulatory element is a transcription terminator. According to certain embodiments, the terminator is derived from Aegilops longissima. According to certain exemplary embodiments, the terminator is the natural / endogenous terminator of the tolerance / resistance conferring gene in Ae. longissima.

[0030] According to certain currently exemplary embodiment, the terminator comprises Heat Shock Protin (HSP) terminator sequence.

[0031] According to certain embodiments, the Triticeae plant is a transgenic plant comprising at least one cell transformed with a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, a construct or an expression vector comprising same.

[0032] The heterologous polynucleotide is as described hereinabove.

[0033] According to certain embodiments, the heterologous polynucleotide is introduced into the at least one cell of the Triticeae plant by means of genome editing using artificially engineered nucleases as is known in the art. According to certain embodiments, the artificially engineered nucleases are selected from the group consisting of meganucleases, Zinc finger nucleases (ZFNs), transcription-activator like effector nucleases (TALENs), and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) / Cas, CRISPR / Cas homologous and CRISPR / Cas modified systems. Each possibility represents a separate embodiment of the present invention. Since most genome-editing techniques can leave behind minimal traces of DNA alterations evident in a small number of nucleotides as compared to transgenic plants, crop plants created through gene editing for expression of the heterologous polynucleotides of the invention could avoid the stringent regulation procedures commonly associated with genetically modified (GM) crop development, and are typically defined as non-transgenic crop plants, particularly non-transgenic crop wheat plants.

[0034] According to certain embodiments, the Triticeae plant is homozygous for the heterologous polynucleotide capable of enhancing or conferring tolerance and / or resistance to the at least one rust disease.

[0035] According to certain embodiments, the Triticeae plant is heterozygous for the heterologous polynucleotide capable of enhancing or conferring tolerance and / or resistance to the at least one rust disease.

[0036] According to certain embodiments, the Triticeae plant comprising within at least one of its cells a heterologous polynucleotide of the invention has enhanced tolerance and / or resistance to stem rust disease compared to a corresponding Triticeae plant devoid of the heterologous polynucleotide.

[0037] According to certain embodiments, the corresponding plant devoid of the heterologous polynucleotide is of the same species. According to certain embodiments, the corresponding plant devoid of the heterologous polynucleotide has the same genetic background.

[0038] According to certain embodiments, the Triticeae plant is a wheat (Triticum) plant.

[0039] According to certain exemplary embodiments, the Triticeae plant of the present invention is a wheat cultivar suitable for commercial agricultural growth, but it is not restricted to a specific plant species, strain, or variety. According to certain exemplary embodiments, the wheat cultivar comprising the heterologous polynucleotide is of a species selected from the group consisting of Triticum turgidum and Triticum aestivum. Each possibility represents a separate embodiment of the present invention. According to certain embodiments, the wheat plant is an elite agricultural cultivar.

[0040] According to certain embodiments, the Triticeae plant is barely (Hordeum) plant. According to these embodiments, the heterologous polynucleotide is capable of conferring or enhancing tolerance and / or resistance of the plant to at least one of stem rust disease, leaf rust disease, and a combination thereof. Each possibility represents a separate embodiment of the present invention.

[0041] According to certain embodiments, the stem rust disease is caused by the fungus Puccinia graminis. According to certain exemplary embodiments, the stem rust disease is caused by the fungus Puccinia graminis f. sp. tritici. According to certain embodiments, the Puccinia graminis f. sp. tritici race is race # 2123.

[0042] The Triticeae plants and cultivars of the present invention are fertile, or male sterile that will produce seeds upon pollination. Seeds and any other plant part that can be used for propagation, including isolated cells and tissue cultures are also encompassed within the scope of the present invention. It is to be understood that a plant produced from said seeds or other propagating material comprises the heterologous polynucleotide that is capable to confers or enhances tolerance and / or resistance to stem rust disease as described herein is encompassed within the teachings of the present invention.

[0043] According to another aspect, the present invention provides a seed of the Triticeae plant, wherein a Triticeae plant grown from the seed comprises at least one cell comprising a heterologous polynucleotide encoding at least one polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, wherein the heterologous polynucleotide is capable of conferring or enhancing tolerance and / or resistance of said Triticeae plant to stem rust disease.

[0044] In some embodiments, the heterologous polynucleotide encodes at least one polypeptide comprising an amino acid sequence having at least 90% identity to the amino acid sequence set forth in any one of SEQ ID NO:1 and SEQ ID NO:3. Each possibility is a separate embodiment.

[0045] In some embodiments, the heterologous polynucleotide encodes at least one polypeptide having the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NO:3. Each possibility is a separate embodiment.

[0046] According to additional aspects, the present invention provides a method for producing a Triticeae plant having enhanced resistance to stem rust diseases, the method comprises introducing into at least one cell of a Triticeae plant susceptible to the stem rust diseases a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, a DNA construct or a vector comprising same, thereby producing a Triticeae plant having enhanced tolerance and / or resistance to said stem rust disease compared to a corresponding control plant.

[0047] According to certain currently exemplary embodiments, the heterologous polynucleotide encodes at least one polypeptide comprising an amino acid sequence having at least 90% identity to the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NO:3. Each possibility is a separate embodiment.

[0048] The polynucleotides and the Triticeae plants are as described hereinabove.

[0049] According to certain embodiments, the control plant is a Triticeae plant or cultivar susceptible to the stem rust disease. According to some embodiments, the control plant is lacking the heterologous polynucleotide. According to certain embodiments, the control plant is lacking the heterologous polynucleotide while having the same genetic background.

[0050] Any method as is known to a person skilled in the art can be used to introduce the heterologous polynucleotide of the present invention into a susceptible Triticeae plant.

[0051] According to certain embodiments, the heterologous polynucleotide is comprised within a DNA construct and / or an expression vector. According to certain embodiments, the heterologous polynucleotide is introduced by transforming said isolated polynucleotide, DNA construct or expression vector into at least one cell of the susceptible Triticeae plant. According to certain embodiments, the isolated polynucleotide is introduced by subjecting at least one cell of the susceptible Triticeae plant to genome editing using artificially engineered nucleases.

[0052] According to certain additional aspects, the present invention provides a method for selecting a Triticeae plant having an enhanced tolerance and / or resistance to stem rust diseases, comprising the steps of: a. providing a plurality of Triticeae plants each comprising at least one cell comprising a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, wherein the polynucleotide is capable of conferring or enhancing tolerance and / or resistance to the Triticeae plants towards stem rust disease; and b. selecting plants showing an enhanced resistance to said stem rust disease compared to a control Triticeae plant or to a pre-determined resistance score value; thereby selecting a Triticeae plant having enhanced resistance to said stem rust disease.

[0053] According to certain embodiments, the control plant is a Triticeae plant susceptible to the stem rust disease. According to some embodiments, the susceptible control Triticeae plant is lacking the heterologous polynucleotide while having the same genetic background.

[0054] The heterologous polynucleotide and the Triticeae plants are as described hereinabove.

[0055] According to certain embodiments, selecting plants resistant to the stem rust disease is performed by inoculating the plants with Puccinia graminis f. sp. tritici and selecting phenotypically resistant plants. According to certain exemplary embodiments, the inoculation and selection is performed at the seedling stage of the plants.

[0056] According to additional or alternative embodiments, selecting plants resistant to a rust disease is performed by detecting the presence of the heterologous polynucleotide within the genetic material of the at least one cell of the Triticeae plant. Any method as is known in the art can be used to detect the heterologous polynucleotide.

[0057] According to certain embodiments, detection is performed by identifying, in a genetic material obtained from the plant, at least one sequence- specific probe that specifically hybridizes under stringent conditions to a nucleic acid sequence having at least 80% identity to a nucleic acid sequence set forth in any one of SEQ ID NO:5 and SEQ ID NO:6 over its entire length. Each possibility is a separate embodiment. According to certain exemplary embodiments, the at least one sequence- specific probe specifically hybridizes under stringent conditions to a nucleic acid sequence set forth in any one of SEQ ID NO:5 and SEQ ID NO:6. Each possibility is a separate embodiment.

[0058] According to certain embodiments, detection of the resistance-conferring polynucleotide is performed by detecting, in a genetic material obtained from the plant, the presence of at least one nucleic acid marker. According to certain currently exemplary embodiments, the marker is amplified by a pair of primers comprising SEQ ID NO: 8 and SEQ ID NO:9. According to certain embodiments, the amplified marker comprises the nucleic acid sequence set forth is SEQ ID NO:7.

[0059] According to certain embodiments, detection of the resistance-conferring polynucleotide is performed by detecting, in a genetic material obtained from the plant, the presence of at least one nucleic acid marker. According to certain currently further exemplary embodiments, the marker is amplified by a pair of primers comprising SEQ ID NO: 11 and SEQ ID NO: 12. According to certain embodiments, the amplified marker comprises the nucleic acid sequence set forth is SEQ ID NO: 10.

[0060] According to yet further aspects, the present invention provides an isolated polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, wherein the polynucleotide, when expressed in a Triticeae plant cell is capable of conferring or enhancing tolerance and / or resistance of the plant to stem rust disease.

[0061] In some embodiments, the isolated polynucleotide encodes at least one polypeptide comprising an amino acid sequence having at least 90% identity to the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NO:3.

[0062] According to certain embodiments, the isolated polynucleotide comprises a nucleic acid sequence having at least 75% identity to the nucleic acid sequence set forth in SEQ ID NO: 2 over the entire length of the polynucleotide.

[0063] According to certain additional or alternative embodiments, the isolated polynucleotide comprises a nucleic acid sequence having at least 75% identity to the nucleic acid sequence set forth in SEQ ID NO: 4 over the entire length of the polynucleotide.

[0064] According to certain embodiments, the isolated polynucleotide comprises a nucleic acid sequence having at least 80% identity to the nucleic acid sequence set forth in SEQ ID NO:5.

[0065] According to certain additional or alternative embodiments, the isolated polynucleotide comprises a nucleic acid sequence having at least 80% identity to the nucleic acid sequence set forth in SEQ ID N0:6.

[0066] According to certain embodiments, the stem rust disease is caused by the fungus Puccinia graminis. According to certain exemplary embodiments, the stem rust disease is caused by the fungus Puccinia graminis f. sp. tritici. According to certain embodiments, the Puccinia graminis f. sp. tritici race is #2123.

[0067] According to additional aspects, the present invention provides a nucleic acid construct comprising the isolated polynucleotides according to some embodiments of the invention, further comprising at least one operably linked regulatory element. According to certain embodiment, the regulatory element is selected from the group consisting of a promoter, an enhancer, and a transcription termination sequence. The regulatory element, particularly the promoter and / or the terminator, can be endogenous or heterologous to the plant comprising the nucleic acid construct. According to certain embodiments, the promoter is heterologous to the wheat plant. According to some embodiment, the heterologous promoter and / or terminator is derived from Ae. longissima. According to some embodiment, the heterologous promoter is a constitutive promoter.

[0068] It is to be understood that any combination of each of the aspects and the embodiments disclosed herein is explicitly encompassed within the disclosure of the present invention.

[0069] Further embodiments and the full scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.

[0070] BRIEF DESCRIPTION OF THE FIGURES

[0071] FIG. 1 shows frequency distribution of stem rust disease resistance scores among the 148 accessions evaluated for stem rust disease phenotype.

[0072] FIG. 2 shows Manhattan plot of SNP and k-mer data analysis for stem rust resistance on chromosome 4. This plot presents the results of analyzing both SNPs (smaller dots) and a subset of k-mers (larger dots) that passed the p value threshold, plotted against their genomic positions.

[0073] FIG. 3 demonstrates the domain structure of the disease resistance protein. Protein domains were deduced from the amino acid sequences of AE.LONG.rl.4SG0331660 (Figure 3A) and AE.LONG.rl.4SG0331670 (Figure 3B), and from the combined sequence of both (Figure. 3C).

[0074] FIG. 4 is a schematic representation of stem rust resistance gene structural annotation. Figure. 4A illustrates two suggested gene structures encoding a short and overlapping longer coding sequences (CDS). Also illustrated are the virus induced gene silencing (VIGS) target locations within exons - VIGS-1 targeting the first exon common to both transcripts and VIGS-2 targeting exon 1 of the longer CDS. Figure. 4B illustrates the long and short CDS comprising a long and a short open reading frame (ORF), respectively.

[0075] FIG. 5 shows the nucleotide sequence of the longer annotated form (as set forth in SEQ ID NO:4) of the novel Sr2127 resistance gene. Exons are marked in uppercase, introns are marked in lowercase, sequences used for targeting by VIGS are underlined (i.e., VIGS-1 and VIGS-2), and sequence used for the VIGS primers are marked in bold.

[0076] FIG. 6 shows a representative image of the reaction of resistant Aegilops longissima accession AEG-6782-2 with and without VIGS targeting the first exon which is common to the two suggested CDS of the resistance-conferring gene (i.e., VIGS-1) to infection with the stem rust conferring Puccinia graminis f. sp. tritici isolate #2127. The fungi- infected AEG-6782-2 plants treated with the empty BSMV vector (no gene fragment) and the fungi-infected AEG-6782-2 untreated plants remained resistant, while VIGS-1 targeting the first common exon rendered AEG-6782-2 plants susceptible to fungi (shown are two representative leaves). The Fielder wheat variety was used as a susceptible control.

[0077] DETAILED DESCRIPTION OF THE INVENTION

[0078] The present invention discloses novel gene that confer or enhance tolerance and / or resistance of Triticeae plants towards stem rust disease, particularly stem rust disease caused by Puccinia graminis f. sp. tritici. The invention further provides Triticeae plants comprising within at least part of its cells heterologous polynucleotide comprising the tolerance and / or resistance-conferring nucleic acid sequence that show enhanced tolerance and / or resistance to the fungus. The invention further provides methods of producing and selecting the wheat plants having enhanced tolerance and / or resistance to the stem rust disease. The present invention further provides methods for controlling a stem disease in agricultural production of Triticeae plant crop.

[0079] Definitions

[0080] The terms “comprise”, “comprising”, “includes”, “including”, “having” and their conjugates mean “including but not limited to”.

[0081] The term “consisting of’ means “including and limited to”.

[0082] The term “consisting essentially of’ means that the composition, method, or structure may include additional ingredients, steps and / or parts, but only if the additional ingredients, steps and / or parts do not materially alter the basic and novel characteristics of the claimed composition, method, or structure.

[0083] As used herein, the singular form “a”, “an” and “the” include plural references unless the context clearly dictates otherwise. For example, the term “a part” with reference to a polynucleotide may include a plurality of polynucleotide parts, including mixtures thereof.

[0084] The term “about” as used herein refers to a numeric value ± 10%.

[0085] As used herein, unless specifically indicated otherwise, the word “or” is used in the inclusive sense of "and / or" and not the exclusive sense of "either / or."

[0086] The term “plant” is used herein in its broadest sense. It also refers to a plurality of plant cells that are largely differentiated into a structure that is present at any stage of a plant's development. Such structures include, but are not limited to, a root, stem, shoot, leaf, flower, petal, fruit, etc. According to certain exemplary embodiments, the term “wheat plant” refers to Triticum turgidum subsp. durum (tetrapioid wheat = macaroni wheat) and T. aestivum subsp. aestivum (hexapioid wheat = bread wheat = common wheat) of the tribe Triticeae, family Poaceae (Gramineae).

[0087] The term “cultivar” (abbreviation cv.) is used herein to denote a plant having a biological status other than a “wild” status, which “wild” status indicates the original non- cultivated or natural state of a plant or accession. The term "cultivar" (for cultivated plants) includes, but is not limited to, semi-natural, semi-wild, weedy, traditional cultivar, landrace, breeding material, research material, breeder's line, synthetic population, hybrid, founder stock / base population, inbred line (parent of hybrid cultivar), segregating population, mutant / genetic stock, and advanced / improved cultivar. The term as used herein includes registered as well as non-registered lines. Examples of cultivars include such cultivated varieties that belong to the species Triticum turgidum including, but not limited to cultivar Svevo, and Triticum aeslivunc including, but not limited to cultivars “Fielder”, Chinese Spring” (CS) and “Galil”.

[0088] The terms Aegilops longissima and Ae. longissima are used herein interchangeably and refer to a wild plant of the genus Aegilops, belonging to the plant family Poaceae (sub-family Pooideae). According to certain embodiments, certain accession within Ae. longissima populations are resistant to stem rust disease.

[0089] The terms “resistant” and “resistance” as used herein refer to the ability of a plant to restrict the growth and development of a specified pest or pathogen and / or the damage they cause when compared to susceptible plant grown under similar environmental conditions and pest or pathogen pressure. The terms encompass both partial and full resistance to infection. A stem rust-resistant plant may either be fully resistant or have low levels of susceptibility to infection by the fungus Puccinia graminis, particularly Puccinia graminis f. sp. tritici.

[0090] The terms “tolerant” and “tolerance” are used herein to indicate a phenotype of a plant wherein at least some of the disease-symptoms remain absent upon exposure of said plant to an infective dose of a pathogen, particularly fungi, whereby the presence of the pathogen can be established, at least under some culture conditions. Tolerant plants are therefore free of the pathogen or are symptomless carriers of the pathogen, particularly the fungi.

[0091] The terms “susceptible” and “susceptibility” as used herein refer to the inability of a plant to restrict the growth and development of a specified pest or pathogen; a susceptible plant displays the detrimental symptoms linked to the pathogen infection, particularly fungi infection. A stem rust- susceptible wheat plant may be either non- resistant, have low levels of resistance or non-tolerant to stem rust disease responsible fungi. Stem rust (caused by Puccinia graminisf. sp. tritici) is a devastating wheat disease causing enormous annual yield losses. The fungal pathogens are changing frequently, giving rise to new virulent types (races), and thus overcoming resistance genes that have been developed. Consequently, the primary wheat gene pool is becoming exhausted and new resistance genes are required. Wild relatives of wheat are yet a relatively available resistance gene pool.

[0092] Accordingly, “conferred tolerance and / or resistance to stem rust disease” or “enhanced tolerance and / or resistance to stem rust disease” refer to a phenotype in which a plant, a wheat plant according to some embodiments of the present invention, has greater health, growth, multiplication, fertility, vigor, strength (e.g., stem strength and resistance), yield, or less severe symptoms associated with infection of the pathogenic fungus causing the stem rust disease compared to a wheat plant that does not have enhanced tolerance and / or resistance to the pathogen. According to certain embodiments of the invention, the wheat plant that does not have enhanced tolerance and / or resistance to the pathogen is lacking the heterologous polynucleotide(s) of the invention. Where a plant is tested for resistance, a control plant is used to assess the degree of the plant resistance. According to certain embodiments of the present invention, the control plant is a plant not manipulated to comprise within its cells the resistance-conferring or enhancing polynucleotide of the invention. The control plant typically, but not necessarily, has the same genetic background as the examined plant. The enhancement can be manifested as an increase of 0.1%, 0.2%, 0.3%, 0.5%, 0.75%, 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 17%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 90%, 100%, or more in health, growth, multiplication, fertility, vigor, strength, or yield, as compared to a control plant. The enhancement can be a decrease of 0.1%, 0.2%, 0.3%, 0.5%, 0.75%, 1%, 1.5%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 12%, 15%, 17%, 20%, 25%, 30%, 35%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% in the symptoms associated with the fungi infection as compared to the control plant. According to certain exemplary embodiments, the examined plant and the control plant are grown under the same conditions.

[0093] As used herein the term “polynucleotide” refers to a single or double stranded nucleic acid sequence which is isolated and provided in the form of an RNA sequence, a complementary polynucleotide sequence (cDNA), a DNA sequence and / or composite polynucleotide sequences (e.g., a combination of the above).

[0094] As used herein, the term “contig” refers to a set of overlapping DNA segments that together represent a consensus region of DNA.

[0095] The terms “protein” and “polypeptide” are used interchangeably herein to designate a series of amino acid residues, connected to each other by peptide bonds between the alpha-amino and carboxyl groups of adjacent residues. The terms “protein” and “polypeptide” refer to a polymer of amino acids, including modified amino acids (e.g., phosphorylated, glycated, glycosylated, etc.) and amino acid analogs, regardless of its size or function. “Protein” and “polypeptide” are often used in reference to relatively large polypeptides, whereas the term “peptide” is often used in reference to small polypeptides, but usage of these terms in the art overlaps. The terms “protein” and “polypeptide” are used interchangeably herein when referring to a gene product and fragments thereof. Thus, exemplary polypeptides or proteins include gene products, naturally occurring proteins, homologs, orthologs, paralogs, fragments and other equivalents, variants, fragments, and analogs of the foregoing.

[0096] The term “gene” as used herein may refer to a DNA nucleic acid sequence that comprises coding sequences necessary for the production of RNA or a polypeptide. A polypeptide can be encoded by a full-length coding sequence or by any part thereof. The term “parts thereof’ when used in reference to a gene refers to fragments of that gene. The fragments may range in size from a few nucleotides to the entire gene sequence minus one nucleotide. Thus, “a nucleic acid sequence comprising at least a part of a gene” may comprise fragments of the gene or the entire gene. The term “gene” as used herein may optionally include sequences located adjacent to the coding region on both the 5' and 3' ends on either end such that the gene corresponds to the length of the full-length mRNA. The sequences which are located 5' of the coding regions and which are present on the mRNA are referred to as 5' non-translated sequences. The sequences which are located 3' or downstream of the coding region and which are present on the mRNA are referred to as 3' non-translated sequences.

[0097] The term “isolated” refers to either: 1) at least partially separated from the natural environment e.g., from a plant cell; 2) prepared or purified by a process that involves the hand of man; 3) not occurring in nature. According to certain embodiments, the polynucleotides of the invention are isolated from Ae. longissima plant cells. According to certain additional or alternative embodiments, the polynucleotides of the invention are produced by recombinant DNA technology in a host organism, for example, a yeast, a bacterial. In less preferred embodiments, the polynucleotides may be produced by chemical synthesis.

[0098] The term “heterologous” with reference to a polynucleotide as is used herein refers to a sequence that is not naturally found in the plant, specifically the wheat plant, and has been artificially introduced into the plant.

[0099] The term “heterozygous” as is used herein means a genetic condition existing when different alleles (forms of a given gene, genetic determinant, or sequences) reside at corresponding loci on homologous chromosomes.

[0100] The term “homozygous” as is used herein, means a genetic condition existing when identical alleles (forms of a given gene, genetic determinant, or sequences) reside at corresponding loci on homologous chromosomes.

[0101] The terms “genetic engineering”, “transformation” and “genetic modification” are all used herein for the transfer of isolated and cloned genes, genetic determinants or polynucleotides into the DNA, usually the chromosomal DNA or genome, of another plant, or to the modification of a gene within the plant genome.

[0102] As used herein, the term “plant part” typically refers to a part of the wheat plant. Examples of plant parts include, but are not limited to, pollen, ovules, leaves, embryos, roots, root tips, anthers, flowers, fruits, stems shoots, and seeds. The term further refers to single cells and cell tissues such as plant cells that are intact in plants, protoplasts, cell clumps, tissue cultures and calli from which wheat plants can be regenerated, that are derived from pollen, ovules, leaves, embryos, roots, root tips, anthers, flowers, fruits, stems shoots, and seeds.

[0103] As used herein, the term “population” refers to a genetically heterogeneous collection of plants sharing a common genetic derivation.

[0104] According to certain aspects, the present invention provides a Triticeae plant comprising at least one genetically engineered cell comprising a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity, 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% to the amino acid sequence set forth in SEQ ID NO: 1, wherein the heterologous polynucleotide is capable of conferring or enhancing tolerance and / or resistance of the plant to stem rust disease. Each possibility represents a separate embodiment of the present invention. According to certain embodiments, the encoded polypeptide comprises the amino acid sequence set forth in SEQ ID NO:1. According to certain embodiments, the encoded polypeptide consists of SEQ ID NO: 1.

[0105] According to certain aspects, the present invention provides a Triticeae plant comprising at least one genetically engineered cell comprising a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity, 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% to the amino acid sequence set forth in SEQ ID NO:3, wherein the heterologous polynucleotide is capable of conferring or enhancing tolerance and / or resistance of the plant to stem rust disease. Each possibility represents a separate embodiment of the present invention. According to certain embodiments, the encoded polypeptide comprises an amino acid sequence having at least 92% identity to the amino acid sequence set forth in SEQ ID NO:3. According to certain embodiments, the encoded polypeptide comprises the amino acid sequence set forth in SEQ ID NO:3. According to certain embodiments, the encoded polypeptide consists of SEQ ID NO: 3.

[0106] According to certain aspects, the present invention provides a Triticeae plant comprising at least one genetically engineered cell comprising a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity, 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% to the amino acid sequence set forth in SEQ ID NO: 17, wherein the heterologous polynucleotide is capable of conferring or enhancing tolerance and / or resistance of the plant to stem rust disease. Each possibility represents a separate embodiment of the present invention. According to certain embodiments, the encoded polypeptide comprises an amino acid sequence having at least 92% identity to the amino acid sequence set forth in SEQ ID NO: 17. According to certain embodiments, the encoded polypeptide comprises the amino acid sequence set forth in SEQ ID NO: 17. According to certain embodiments, the encoded polypeptide consists essentially of SEQ ID NO: 17.

[0107] According to certain aspects, the present invention provides a Triticeae plant comprising at least one genetically engineered cell comprising a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity, 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, or at least 99% to the amino acid sequence set forth in SEQ ID NO: 18, wherein the heterologous polynucleotide is capable of conferring or enhancing tolerance and / or resistance of the plant to stem rust disease. Each possibility represents a separate embodiment of the present invention. According to certain embodiments, the encoded polypeptide comprises an amino acid sequence having at least 92% identity to the amino acid sequence set forth in SEQ ID NO: 18. According to certain embodiments, the encoded polypeptide comprises the amino acid sequence set forth in SEQ ID NO: 18. According to certain embodiments, the encoded polypeptide consists essentially of SEQ ID NO: 18.

[0108] As used herein, “sequence identity” or “identity” in the context of two polypeptide or nucleic acid sequences includes reference to the residues in the two sequences which are the same when aligned. When percentage of sequence identity is used in reference to proteins it is recognized that residue positions which are not identical often differ by conservative amino acid substitutions, where amino acid residues are substituted for other amino acid residues with similar chemical properties (e.g., charge or hydrophobicity) and therefore do not change the functional properties of the molecule. Where sequences differ in conservative substitutions, the percent sequence identity may be adjusted upwards to correct for the conservative nature of the substitution. Sequences which differ by such conservative substitutions are considered to have “sequence similarity” or “similarity”. Means for making this adjustment are well-known to those of skill in the art. Typically this involves scoring a conservative substitution as a partial rather than a full mismatch, thereby increasing the percentage sequence identity. Thus, for example, where an identical amino acid is given a score of 1 and a non-conservative substitution is given a score of zero, a conservative substitution is given a score between zero and 1. The scoring of conservative substitutions is calculated, e.g., according to the algorithm of Henikoff S and Henikoff JG. (Amino acid substitution matrices from protein blocks. Proc. Natl. Acad. Sci. U.S.A. 89(22), 10915-9, 1992).

[0109] Identity (e.g., percent homology) can be determined using any homology comparison software, including for example, the BlastN, BlastX or Blastp software of the National Center of Biotechnology Information (NCBI) such as by using default parameters. A widely used and accepted computer program for performing sequence alignments is CLUSTALW vl.6 (Thompson, et al. Nucl. Acids Res., 22: 4673-4680, 1994).

[0110] According to some embodiments of the invention, the identity is a global identity, i.e., over the entire nucleic acid sequences of the invention and not over portions thereof. According to some embodiments of the invention, the identity is a partial identity, i.e., over fragment or fragments of the nucleic acid sequences of the invention and not over the entire sequence, as described herein.

[0111] According to certain aspects, the present invention provides an isolated polynucleotide encoding at least one polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, wherein the polynucleotide, when expressed in a Triticeae plant cell is capable of conferring or enhancing tolerance and / or resistance of the plant to stem rust disease.

[0112] According to certain embodiments, the heterologous polynucleotide comprises a nucleic acid sequence having at least 75%, at least 76%, at least 77%, at least 78%, at least 79%, at least 80%, at least 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or more identity to the nucleic acid sequence set forth in SEQ ID NO:2 over its entire length. Each possibility represents a separate embodiment of the present invention.

[0113] According to certain embodiments, the heterologous polynucleotide comprises a nucleic acid sequence having at least 80%, at least 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or more identity to the nucleic acid sequence set forth in SEQ ID NO:5. Each possibility represents a separate embodiment of the present invention.

[0114] According to certain embodiments, the heterologous polynucleotide comprises a nucleic acid sequence having at least 75%, at least 76%, at least 77%, at least 78%, at least 79%, at least 80%, at least 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or more identity to the nucleic acid sequence set forth in SEQ ID NO:4 over its entire length. Each possibility represents a separate embodiment of the present invention.

[0115] According to certain embodiments, the heterologous polynucleotide comprises a nucleic acid sequence having at least 80%, at least 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or more identity to the nucleic acid sequence set forth in SEQ ID NO:6. Each possibility represents a separate embodiment of the present invention.

[0116] The present invention further discloses the sequence set forth in SEQ ID NO: 14 located 3’ to any one of SEQ ID NO:2 and SEQ ID NO:4 that may include an additional translatable sequence common to both short ORF and longer ORF. The nucleotide sequence of this additional translatable sequence is set forth in SEQ ID NO: 16.

[0117] The translatable nucleic acid sequence set forth in SEQ ID NO: 16 may encode an amino acid sequence that when translated in continuation to the short ORF corresponding to the short polypeptide set forth in SEQ ID NO: 1, yields a polypeptide having the amino acid sequence as set forth in SEQ ID NO: 17.

[0118] The translatable nucleic acid sequence set forth in SEQ ID NO: 16 may encode an amino acid sequence that when translated in continuation to the longer ORF corresponding to the longer polypeptide set forth in SEQ ID NO:3, yields a polypeptide having the amino acid sequence as set forth in SEQ ID NO: 18.

[0119] According to certain embodiments, the heterologous polynucleotide of the present invention comprising a nucleic acids sequence having at least 75% identity to any one of SEQ ID NO:2 and SEQ ID NO:4 further comprises 3’ sequence having a nucleic acid sequence having at least 80% identity to SEQ ID NO: 14. According to certain embodiments, the 3’ sequence comprises a nucleic acid sequence having at least at least 81%, at least 82%, at least 83%, at least 84%, at least 85%, at least 86%, at least 87%, at least 88%, at least 89%, at least 90%, at least 91%, at least 92%, at least 93%, at least 94%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or more to SEQ ID NO: 14. According to certain embodiments, the 3’ sequence comprises a transcribable sequence having the nucleic acid sequence set forth in SEQ ID NO: 16. According to these embodiments, the heterologous polynucleotide encodes a polypeptide having at least 80% identity to the amino acid sequence set forth in any one of SEQ OD NO: 17 and SEQ ID NO: 18.

[0120] Reference is made to Table 1 as appears in Example 7, listing the herein disclosed isolated proteins and nucleic acid sequences derived from the novel Sr2127 gene according to their SEQ ID NOs.

[0121] According to additional aspects, the present invention provides a nucleic acid construct comprising the isolated polynucleotide of the invention, further comprising at least one regulatory element for directing transcription of the nucleic acid sequence in the host plant cell, particularly in a wheat plant cell.

[0122] According to certain embodiments, the regulatory element is selected from the group consisting of an enhancer, a promoter, a transcription termination sequence, and the like. According to some embodiments of the invention, the regulatory sequence is operably linked to the isolated polynucleotide.

[0123] A nucleic acid sequence (particularly a coding nucleic acid sequence) is “operably linked” to a regulatory sequence (e.g., promoter) if the regulatory sequence is capable of exerting a regulatory effect on the coding sequence linked thereto.

[0124] According to certain embodiments, the nucleic acid construct is an expression vector comprising a promoter operably linked to the polynucleotide of the invention. As used herein, the term “promoter” refers to a region of DNA placed upstream of the transcriptional initiation site of a gene to which RNA polymerase binds to initiate transcription of RNA. The promoter controls where (e.g., which portion of a plant) and / or when (e.g., at which stage or condition in the lifetime of an organism or a cell thereof) the gene is expressed.

[0125] According to some embodiments of the invention, the regulatory sequence is heterologous to the isolated polynucleotide and / or to the host cell.

[0126] As used herein the phrase “heterologous regulatory sequence”, for example “heterologous promoter” refers to regulatory sequence from a different species or from the same species but from a different gene locus as of the isolated polynucleotide sequence.

[0127] According to additional or alternative embodiments of the invention, the regulatory sequence forming part of the nucleic acid construct is a regulatory sequence operatively linked the tolerance / resistance conferring gene in Ae. Longissima.

[0128] Any suitable promoter sequence can be used within the nucleic acid construct of the present invention. Preferably the promoter is selected from the group consisting of a constitutive promoter, a tissue-specific, or biotic-stress specific promoter, particularly promoters inducible by fungi infection. According to some embodiments of the invention, the promoter is a plant promoter suitable for expression of the isolated polynucleotide of the invention in a wheat plant cell. An exemplary promoter to be used in wheat plant is Lr21 promoter (Huang, Li, et al., 2003, Genetics 164.2:655-664). According to certain embodiments, the promoter is the natural promoter of the tolerance / resistance conferring gene in Ae. longissima.

[0129] According to certain embodiments, the promoter is comprised within the nucleic acid sequence upstream to the start codon of SEQ ID NO:2, said nucleic acid sequence is at least 75%, at least 80%, at least 85%, at least 90%, at least 95% or is identical the nucleic acid sequence set forth in SEQ ID NO:7.

[0130] According to certain embodiments, the promoter is comprised within the nucleic acid sequence upstream to the start codon of SEQ ID NO:4, said nucleic acid sequence is at least 75%, at least 80%, at least 85%, at least 90%, at least 95% or is identical the nucleic acid sequence set forth in SEQ ID NO: 10. According to certain embodiments, the nucleic acid construct further comprises a termination sequence located 3’ to the heterologous nucleic acid sequence having at least 75% identity to SEQ ID NO:2 or SEQ ID NO:4. According to certain embodiments, the termination sequence is the natural termination sequence of the tolerance / resistance conferring gene in Ae. longissima. According to certain exemplary embodiments, the termination sequence is comprised within a nucleic acids sequence having at least 75%, at least 80%, at least 85%, at least 90%, at least 95% or is identical the nucleic acid sequence set forth in SEQ ID NO: 14 located 3’ to any one of SEQ ID NO:2 and SEQ ID NO:4.

[0131] The nucleic acid construct of the present invention can further comprise at least one marker (reporter) gene, operably linked to a regulatory element (such as a promoter) that allows transformed cells containing the marker to be either recovered by negative selection (by inhibiting the growth of cells that do not contain the selectable marker gene), or by positive selection (by screening for the product encoded by the markers gene). Many commonly used selectable marker genes for plant transformation are known in the art, and include, for example, genes that code for enzymes that metabolically detoxify a selective chemical agent which may be an antibiotic or an herbicide, or genes that encode an altered target which is insensitive to the inhibitor. Several positive selection methods are known in the art, such as mannose selection. Alternatively, marker-less transformation can be used to obtain plants without mentioned marker genes, the techniques for which are known in the art. The construct according to the present invention being a transformation vector, an expression vector or a combination thereof can be, for example, plasmid, a bacmid, a phagemid, a cosmid, a phage, a virus, or an artificial chromosome.

[0132] The polynucleotides of the invention and construct comprising same can be chemically synthesized by any method as is known in the Art.

[0133] The nucleic acid construct comprising the polynucleotide conferring or enhancing tolerance and / or resistance to stem rust disease as disclosed herein may be used to produce a Triticeae plant, particularly wheat plant having enhanced tolerance and / or resistance to the stem rust disease. According to certain embodiments, the tolerance / resistance- conferring polynucleotide or the construct comprising same is introduced into a susceptible wheat plant, typically to a wheat cultivar used in agriculture. The tolerance / resistance conferring nucleic acid sequence may be introduced to a recipient wheat plant by any method as is known to a person skilled in the art. According to certain embodiments, the isolated polynucleotide or the construct comprising same according to the teachings of the invention can be introduced by transformation. Transformation is optionally followed by selection of offspring plants comprising the resistance-conferring sequence and exhibiting resistance to the fungal disease stem rust.

[0134] According to additional aspects, the present invention provides a method for producing a Triticeae plant having enhanced resistance to stem rust diseases, the method comprises introducing into at least one cell of a Triticeae plant susceptible to the stem rust diseases a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, a DNA construct or a vector comprising same, thereby producing a Triticeae plant having enhanced tolerance and / or resistance to said stem rust disease compared to a corresponding control plant.

[0135] The heterologous polynucleotide , constructs and / or vectors comprising same are as described hereinabove.

[0136] Methods for transforming a plant cell with polynucleotides and / or constructs comprising same according to the present invention are known in the art. As used herein the term “transformation” or “transforming” describes a process by which a foreign nucleic acid sequence, such as a vector, enters and changes a recipient cell into a transformed, genetically engineered, or transgenic cell. Transformation may be stable, wherein the nucleic acid sequence is integrated into the plant genome and as such represents a stable and inherited trait, or transient, wherein the nucleic acid sequence is expressed by the cell transformed but is not integrated into the genome, and as such represents a transient trait. According to typical embodiments the nucleic acid sequences of the present invention are stably transformed into a plant cell resulting in a cell comprising within its genome the heterologous polynucleotide. There are various methods of introducing foreign nucleic acid sequences into both monocotyledonous and dicotyledonous plants (for example, Potrykus I. 1991. Annu Rev Plant Physiol Plant Mol Biol 42:205-225; Shimamoto K. et al., 1989. Nature 338:274-276).

[0137] The principal methods of the stable integration of exogenous DNA into plant genomic DNA includes two main approaches:

[0138] Agrobacterium-mediated gene transfer: The Agrobacterium-mediated system includes the use of plasmid vectors that contain defined DNA segments which integrate into the plant genomic DNA. Methods of inoculation of the plant tissue vary depending upon the plant species and the Agrobacterium delivery system. Agrobacterium mediated transformation protocols for wheat are known to a person skilled in the art. High efficiency transformation of wheat embryos mediated by Agrobacterium tumefaciens is described by Ishida et al. (Ishida Y., et al. In: Ogihara Y., Takumi S., Handa H. (eds) Advances in Wheat Genetics: From Genome to Field. Springer, Tokyo. DOI 10.1007 / 978-4-431 -55675 -6_ 18) .

[0139] Direct nucleic acid transfer: There are various methods of direct nucleic acid transfer into plant cells, however, not all are applicable in Triticeae. A directed transformation method that any be used is microparticle bombardment, in which the nucleic acid is adsorbed on microprojectiles such as magnesium sulfate crystals or tungsten particles, and the microprojectiles are physically accelerated into cells or plant tissues.

[0140] According to other embodiments, the tolerance / resistance conferring polynucleotides of the present invention can be introduced into the genome of at least one cell of a susceptible Triticeae plant using the techniques of genome editing. Genome editing is a reverse genetics method which uses artificially engineered nucleases to cut and create specific double- stranded breaks at a desired location(s) in the genome, which are then repaired by cellular endogenous processes such as, homology directed repair (HDR) and non-homologous end-joining (NHEJ). NHEJ directly joins the DNA ends in a double- stranded break, while HDR utilizes a homologous sequence as a template for regenerating the missing DNA sequence at the break point. In order to introduce specific nucleotide modifications to the genomic DNA, a DNA repair template containing the desired sequence must be present during HDR. Genome editing cannot be performed using traditional restriction endonucleases since most restriction enzymes recognize a few base pairs on the DNA as their target and the probability is very high that the recognized base pair combination will be found in many locations across the genome resulting in multiple cuts not limited to a desired location. To overcome this challenge and create site- specific single- or double- stranded breaks, several distinct classes of nucleases have been discovered and bioengineered to date. These include the meganucleases, Zinc finger nucleases (ZFNs), transcription-activator like effector nucleases (TALENs) and CRISPR / Cas system.

[0141] According to certain additional aspects, the present invention provides a method for selecting a Triticeae plant having an enhanced tolerance and / or resistance to stem rust diseases, comprising the steps of: a. providing a plurality of Triticeae plants each comprising at least one cell comprising a heterologous polynucleotide encoding at least one polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, wherein the polynucleotide is capable of conferring or enhancing tolerance and / or resistance to the Triticeae plants towards stem rust disease; and b. selecting plants showing an enhanced resistance to said stem rust disease compared to a control Triticeae plant or to a pre-determined resistance score value; thereby selecting a Triticeae plant having enhanced resistance to said stem rust disease.

[0142] According to certain embodiments, the each of the plurality of Triticeae plants comprises at least one cell comprising a heterologous polynucleotide encoding at least one polypeptide comprising an amino acid sequence having at least 90% identity to the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NO:3. Each possibility represents a separate embodiment of the presented invention.

[0143] According to certain embodiments, the each of the plurality of Triticeae plants comprises at least one cell comprising a heterologous polynucleotide encoding at least one polypeptide comprising an amino acid sequence having at least 90%, at least 92%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or more identity to the amino acid sequence set forth in any one of SEQ ID NO: 3. According to certain embodiments, selecting plants resistant to the stem rust disease is performed by inoculating the plants with Puccinia graminis f. sp. tritici and selecting phenotypically resistant plants. According to additional or alternative embodiments, selecting plants resistant to a rust disease is performed by detecting the presence of the heterologous polynucleotide within the at least one cell of the Triticeae plant. Any method as is known in the art can be used to detect the heterologous polynucleotide.

[0144] According to certain embodiments, detection is performed by identifying, within a genetic material obtained from the plant, at least one sequence- specific probe that specifically hybridizes under stringent conditions to a nucleic acid sequence having at least 75% identity to the nucleic acid sequence set forth in any one of SEQ ID NO: 2 and SEQ ID NO:4 over its entire length and / or to a nucleic acid sequence having at least 80% identity to the nucleic acid sequence set forth in any one of SEQ ID NO:5 and SEQ ID NO:6.

[0145] According to certain embodiments, detection of the resistance-conferring polynucleotide is performed by detecting, in a genetic material obtained from the plant, the presence of at least one nucleic acid marker.

[0146] According to certain currently exemplary embodiments, the marker is amplified by a pair of primers comprising SEQ ID NO: 8 and SEQ ID NO:9. According to certain embodiments, the amplified marker comprises the nucleic acid sequence set forth is SEQ ID NO:7. According to certain currently further exemplary embodiments, the marker is amplified by a pair of primers comprising SEQ ID NO: 11 and SEQ ID NO: 12. According to certain embodiments, the amplified marker comprises the nucleic acid sequence set forth is SEQ ID NO: 10.The following examples are presented in order to more fully illustrate some embodiments of the invention. They should, in no way be construed, however, as limiting the broad scope of the invention. One skilled in the art can readily devise many variations and modifications of the principles disclosed herein without departing from the scope of the invention.

[0147] EXAMPLES

[0148] Materials and Methods

[0149] Plant materials and genomic data

[0150] The Aegilops longissima accessions used in this study were obtained from the Harold and Adele Lieberman Germplasm Bank at the Institute for Cereal Crops Improvement (ICCI) at Tel Aviv University, Israel (en-lifesci.tau. ac.il / icci). The diversity panel consisted of 380 accessions, including AEG-6782-2, collected from 80 sites across Israel. All accessions were self-fertilized for three to five generations with bagged heads to prevent cross-fertilization. Accessions were chosen to maximize geographic distribution and minimize redundancies from the same collection site. The re-sequencing was conducted on selected 207 Ae. longissima accessions using X10 depth coverage to generate high-resolution genomic data for further genetic and genomic analysis (data not shown). The accession AEG-6782-2 was used as the reference for genome assembly (Avni R et al., 2022. Plant Journal 110, 179-192). The genome assembly was conducted using the TRITEX pipeline, resulting in a 6.70 Gb genome with 31,183 annotated genes. Structural gene annotation followed the methodology of Monat et al. (Monat C et al., 2019. Genome Biol 20, 284).

[0151] Plant inoculation and phcnotyping

[0152] Seedlings were tested for stem rust resistance. Plants were grown in temperature- controlled greenhouses at 22 ± 2°C with a 14-hour day / 10-hour night photoperiod. Inoculation involved applying a Puccinia graminis f. sp. tritici urediniospore suspension in Soltrol 170 mineral oil (Chevron Phillips), which evaporated post-application. Seedlings were inoculated at the one-leaf stage (7-10 days) and post-inoculation plants were incubated in a dew chamber at 100% relative humidity for 24 hours before transfer to the greenhouse. Stem rust inoculations were done at 18°C for 24 hours, followed by 12-14 days in the greenhouse at 22°C. Each accession had three replicates scored for infection type (IT) 7-10 days post-inoculation (dpi) for stem rust using a 0 to 4 scale converted to a 1 to 9 scale for clarity.

[0153] GWAS analysis

[0154] Genome-Wide Association Study (GWAS) was conducted using the GAPIT3 package in R software (version 2021.09.2+382) following GAPIT's instructions (Wang J et al., 2021. Genomics, Proteomics & Bioinformatics, 19(4), 629-640). The dataset included over 41 million Single Nucleotide Polymorphisms (SNPs) across all chromosomes. SNPs with a Minor Allele Frequency (MAF) threshold > 0.05% and less than 20% missing data were included, resulting in 2,054,786 SNPs for analysis. The association mapping used multiple statistical models: General Linear Models (GLM), FarmCPU, Mixed Linear Models (MLM), Multi-locus Mixed Linear Models (MLMM), and Blink (Lipka A E et al., 2012. Genetics and population analysis GAPIT: genome association and prediction integrated tool. 28(18), 2397-2399. doi:

[0155] 10.1093 / bioinformatics / bts444; Wang et al., 2021, ibid). A threshold of LOD score 7 (- log 10 p) was set to identify significant SNP markers. Manhattan plots were generated to summarize GWAS results, with the X-axis representing genomic positions and the Y-axis showing the negative logarithm of P-values. Peaks indicated strong associations between genomic regions and traits. GAPIT produced a single Manhattan plot for the entire genome and individual plots for each chromosome. k-mer analysis

[0156] A k-mer based association analysis (Li L F et al., 2022. Molecular Plant, 15(7 March), 488-503; Voichek Y et al., 2020. Nature Genetics, 52(April 13), 534-540; Yu G et al., 2022. Nature Communication, 13, 1607) was also employed to identify significant genomic markers correlated with the stem rust phenotype in plants. A GWAS was performed using a k-mer analysis approach to identify k-mers with 5% and 10% significance levels. The presence of k-mers in each accession was quantified, and the raw data was obtained. The accession data was analyzed for reads matching the significant k- mers. These reads were used to assemble contigs / scaffolds. The contigs were aligned against a reference genome, and the k-mers were aligned against the same reference genome. A Manhattan plot was generated to visually present the results, including all k- mers and the subset of k-mers that intersected with the contigs. Loci that consistently appeared both in k-mer and in SNP GWAS analysis were taken for further studies.

[0157] Virus-Induced Gene Silencing (VIGS)

[0158] Barley stripe mosaic virus (BSMV) vectors (pa, pP, and py) were based on previously described constructs (Yuan C et al., 2011. PLoS One 6(10): e26468). The py vector contained a ligation-independent cloning (LIC) site for direct VIGS target sequence cloning. Positive and negative controls used py-anti Prostaglandin D Synthase (PDS) and py-empty vectors, respectively. The novel stem rust sequence was analyzed using si-Fi software for RNAi-target design and off-target prediction against wheat cDNA annotation IWGSC RefSeq vl.O to select VIGS target sequences. Two regions were selected as the VIGS target sequences.

[0159] A first VIGS target sequence (SEQ ID NOG), located in the first exon common to the two suggested annotations of the ORF of the gene. Specifically, this VIGS target sequence is located to bp 15-321 of the nucleic acid sequence set forth in SEQ ID NO:2 (encoding the disclosed amino acid set forth in SEQ ID NO: 1 from a short ORF), that is shared with (corresponding to) bp 2758-3064 of the nucleic acid sequence set forth in SEQ ID NO:4 (encoding the disclosed amino acid set forth in SEQ ID NOG from a longer overlapping ORF).

[0160] A second VIGS target sequence (SEQ ID NO: 10), located to the first exon as suggested by the longer annotation of the ORF. Specifically, this VIGS target sequence is located to bp 196-438 of the nucleic acid sequence set forth in SEQ ID NO:4 (encoding the disclosed amino acid set forth in SEQ ID NOG from the longer ORF).

[0161] Target sequences were produced via RT-PCR using total RNA extracted from healthy Ae. longissima accession AEG-6782-2. The py vector was linearized with restriction enzyme Apal (New England Biolabs, R0114S) at 25°C for 2 h to produce a Ligation Independent Cloning (LIC) site. Both the linearized py vector and purified PCR product were then treated with T4 DNA polymerase to generate complementary sticky ends. The treated PCR products were mixed with 2 pL treated py vector for ligation and transformed into competent DH5a E. coli cells. Plasmids were purified from PCR- verified bacteria and Sanger-sequenced. The verified plasmids were introduced into Agrobacterium tumefaciens strain GV3101 by electroporation and plated on LB agar containing kanamycin (50 pg / mL) and rifampicin (25 pg / mL). Single colonies were propagated overnight, diluted 1:50, and grown at 30°C overnight. Cultures were spun down, and cells were re-suspended in infiltration medium (10 mM MES, 10 mM MgCh, 200 pM aceto syringone), adjusted to a final optical density of 1.0 at 600 nm, and incubated at room temperature without shaking for 3 h or longer. Equal volumes of A. tumefaciens strains carrying either the py construct, or pa, or pP were combined and infiltrated into the adaxial side of 4-week-old Nicotiana benthamiana leaves using a 1- mL syringe. The infiltrated N. benthamiana leaves were harvested 6 days post- agroinfiltration and ground using a pre-chilled mortar and pestle in 10 mM potassium phosphate buffer (pH 7.0) containing 1-2% (w / v) Celite 545 AW (Sigma- Aldrich) abrasive. The extracted sap was then used to rub-inoculate the second leaf of two-leaf stage Ae. longissima seedlings, and the seedling are grown to 4-leaf stage. The new leaves were then inoculated with stem rust isolate (about 13 days after virus infection), and symptoms were recorded after additional 8-10 days.

[0162] Example 1: Screening the panel of Sh. longissima against stem rust isolate Sr#2127

[0163] To explore additional rust-resistance genes, a diversity panel of 207 Ae. longissima accessions was screened by inoculating seedlings with the stem rust inducing fungus Puccinia graminis f. sp. tritici isolate #2127. Phenotype data could be obtained for 148 accessions, revealing that 80% exhibited susceptibility (scores 7-9), 11% showed moderate resistance (scores 3-5), and only 9% displayed high resistance (score 1) (Figure 1). The broad spectrum of resistance observed indicates substantial genetic diversity within the population.

[0164] Example 2: GWAS using multi-Manhattan analyses for stem rust resistance trait across all models

[0165] To identify candidate stem rust resistance gene(s) GWAS analysis was performed using reference genome of Ae. longissima (Avni et al., 2022, ibid), 10X sequenced genomes of 207 Ae. longissima accessions (unpublished data) and above phenotyping results. This analysis identified the known resistance gene Sr62 (Yu et al., 2022, ibid) on chromosome 1 for stem rust. Additionally, another promising SNP (S4S_ 774934950) on chromosome 4 that was significantly associated in four different models was detected.

[0166] Example 3: A-mer based association

[0167] To verify the above GWAS SNP-based results additional k-mer based analysis was performed. The analysis resulted in several significant A-mcrs near the genomic location of the significant SNP (S4S_ 774934950) (Figure 2). The genomic region of the reference Ae. longissima genome was explored and several candidate genes flanking the significant SNP and k-mers, spanning 500 Kb, were extracted. Of these, the Disease Resistance NLR Protein appeared to be related to disease resistance. Therefore, this gene was prioritized for validation through VIGS analysis. It was observed that, two disease resistance genes, AE.LONG.rl.4SG0331660.1 (2239 bp) and AE.LONG.rl.4SG0331670.1 (900 bp), are located near the identified SNPs and k'-mcrs. However, it appears that these genes were not properly annotated. The proteins deduced from their nucleotide sequences contained only partial domains for disease resistance. For instance, the AE.LONG.rl.4SG0331660 protein had only the LRR domain, while the AE.LONG.rl.4SG0331670 protein included only the CC domain (Figure 3A, 3B, respectively). In accordance, when both gene sequences were combined, all the different domains typically found in an NLR protein were identified (Figure 3C). Thus, the present invention, unexpectedly discloses a new gene, temporarily named Sr2127, resulting from the combination of the two previously reported genes. The analysis suggested that the genomic sequence of the transcribed part of the gene includes nucleic acid sequence that is 3202 bp long (as set forth in SEQ ID NO: 2) and encodes a protein of 911 amino acids (as set forth in SEQ ID NO: 1). However, the analysis further suggested that the translated ORF may be longer, including an additional, preceding, exon upstream to this ORF that results in a longer protein of 1057 amino acids (as set forth in SEQ ID NO:3). This longer protein would be encoded by a longer genomic sequence of a length of 5945 bp long (as set forth in SEQ ID NO:4) (Figures 4A-4B).

[0168] Example 4: Validation of stem rust resistance sene via VIGS

[0169] To validate the function of the candidate gene described in Example 3 above, virus- induced gene silencing (VIGS) (Yuan et al., 2011, ibid, as described in the method section hereinabove) was employed to suppress the gene expression in the resistant Ae. longissima accession AEG-6782-2. Silencing the gene is expected to render the resistant plant susceptible to infection with Puccinia graminis f. sp. tritici inducing stem rust disease.

[0170] First, the candidate gene expression was suppressed by targeting a non-overlapping (i.e., within the exon) gene-specific sequence (SEQ ID NO:7) located to exon which is common to the two suggested CDS encoding the short and an overlapping longer ORF described in Example 3 above (Figure 4A; marked as VIGS-1). Specifically, the VIGS-1 target sequence is located to bp 15-321 of the shorter annotation denoted by SEQ ID NO:2, corresponding to bp 2758-3064 of the longer annotation denoted by SEQ ID NO:4) (Figure 5).

[0171] Thereafter, plants were infected with the stem rust inducing isolate #2127. As is apparent from Figure 6, silencing the expression of the resistance-conferring Sr2127 gene within its parent resistant Ae. Longissimi resulted in susceptibility of the plant to the stem rust isolate. The resistant Ae. Longissimi plant, with or without an empty vector, showed very minor symptoms of stem rust disease, while the Ae. Longissimi plant in which the Sr2127 gene was silenced showed significant disease symptoms, closer to the system observed in the susceptible wheat cultivar Fielder. function of the long ORF encoded

[0172] To determine if the protein product potentially translated from the longer CDS is an essential gene product for conferring resistance to stem rust, a second VIGS target sequence (SEQ ID NO: 10) was designed to target another non-overlapping gene-specific sequence, located to the first exon of the longer suggested CDS encoding the longer ORF (Figure 4A; marked as VIGS-2). Specifically, this VIGS target sequence (SEQ ID NO: 10) is located to bps 196-438 of the nucleic acid sequence set forth in SEQ ID NO:4 (encoding the disclosed amino acid set forth in SEQ ID NOG) (Figure 5).

[0173] VIGS transformation and susceptibility to stem rust disease is examined as described in Example 4 hereinabove.

[0174] Example 6: Generation of transgenic, resistant plants

[0175] To further validate the ability of the herein disclosed gene Sr2127 to confer stem rust resistance, and more particularly for the purpose of determining the one or more protein products of this gene which are essential for providing resistance to stem rust disease - as exemplified in Example 4 hereinabove - transgenic wheat lines (cv. Fielder) expressing the short protein (SEQ ID NO: 1) or the longer protein (SEQ ID NO: 3) of the Sr2127 gene are generated.

[0176] Transformation is conducted as described in Hayta et al., 2021 (Hayta, S et al., 2021. Current Protocols, 1(3), e58), using the genomic sequences (comprising SEQ ID NOG or SEQ ID NO:4) driven by a constitutive 35S promoter. Independent To transgenic events are produced, assessed for transgene copy numbers, using Droplet PCR essentially as described inSharma et al., 2024 (Sharma, D et al. 2024. Nat Commun 15:9925) and evaluated for resistance to stem rust disease provoked by inoculation with Puccinia graminis f. sp. tritici isolate #2127 as described hereinabove. Example 7: Sequences

[0177] Table 1: List of sequences of isolated polynucleotides and proteins derived from A e.

[0178] Longissimi and synthetic sequences related thereto according to their SEP ID NO. The foregoing description of the specific embodiments will so fully reveal the general nature of the invention that others can, by applying current knowledge, readily modify and / or adapt for various applications such specific embodiments without undue experimentation and without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. The means, materials, and steps for carrying out various disclosed functions may take a variety of alternative forms without departing from the invention.

Claims

CLAIMS1. A Triticeae plant comprising at least one cell comprising a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, wherein the heterologous polynucleotide is capable of conferring or enhancing tolerance and / or resistance of the plant to stem rust disease.

2. The Triticeae plant of claim 1, wherein the heterologous polynucleotide encodes at least one polypeptide comprising an amino acid sequence having at least 90% identity to the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NO:3.

3. The Triticeae plant of any one of claims 1-2, wherein the heterologous polynucleotide encodes at least one polypeptide having the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NO:3.

4. The Triticeae plant of claim 1, wherein the heterologous polynucleotide comprises a nucleic acid sequence having at least 75% identity to at least one nucleic acid sequence set forth in any one of SEQ ID NO: 2 and SEQ ID NO: 4 over the entire length of the polynucleotide.

5. The Triticeae plant of claim 4, wherein the heterologous polynucleotide comprises a nucleic acid sequence set forth in any one of SEQ ID NO:2 and SEQ ID NO:4.

6. The Triticeae plant of claim 1, wherein the heterologous polynucleotide comprises a nucleic acid sequence having at least 80% identity to at least one nucleic acid sequence set forth in any one of SEQ ID NO:5 and SEQ ID NO:6.

7. The Triticeae plant of claim 6, wherein the heterologous polynucleotide comprises a nucleic acid sequence set forth in any one of SEQ ID NO:5 and SEQ ID NO:6.

8. The Triticeae plant of any one of claims 1-7, wherein said Triticeae plant is a transgenic plant comprising at least one cell transformed with the heterologous polynucleotide.

9. The Triticeae plant of claim 8, wherein the heterologous polynucleotide further comprises at least one regulatory element capable of controlling the expression of said heterologous polynucleotide in the at least one plant cell.

10. The Triticeae plant of claim 9, wherein the at least one regulatory element is selected from the group consisting of a promoter, an enhancer, a termination sequences and any combination thereof.

11. The Triticeae plant of any one of claims 1-7, wherein the heterologous nucleotide is introduced into the at least one cell by means of genome editing, using at least one artificially engineered nuclease.

12. The Triticeae plant of any one of any one of claims 1-11, wherein said plant is selected from a plant homozygous for the heterologous polynucleotide capable of enhancing or conferring tolerance and / or resistance to the at least one rust disease and a plant heterozygous for said heterologous polynucleotide capable of enhancing or conferring tolerance and / or resistance to the at least one rust disease.

13. The Triticeae plant of any one of any one of claims 1-12, wherein said plant shows the phenotype of enhanced tolerance and / or resistance to stem rust disease compared to a corresponding Triticeae plant devoid of the heterologous polynucleotide.

14. The Triticeae plant of any one of any one of claims 1-13, wherein said plant is a cultivar suitable for commercial agricultural growth.

15. The Triticeae plant of any one of any one of claims 1-14, wherein said plant is a wheat plant selected from Triticum turgidum and Triticum aestivum.

16. The Triticeae plant of any one of claims 1-15, wherein the stem rust disease is caused by the fungus Puccinia graminisf. sp. tritici.

17. A seed of the Triticeae plant of any one of claims 1-16, wherein a Triticeae plant grown from the seed comprises at least one cell comprising a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, wherein the heterologous polynucleotide is capable of conferring or enhancing tolerance and / or resistance of said Triticeae plant to stem rust disease.

18. The seed of the Triticeae plant of claim 17, wherein the heterologous polynucleotide encodes at least one polypeptide comprising an amino acid sequence having at least 90% identity to the amino acid sequence set forth in anyone of SEQ ID NO: 1 and SEQ ID NO:3.

19. The seed of the Triticeae plant of any one of claims 17-18, wherein the heterologous polynucleotide encodes at least one polypeptide having the amino acid sequence set forth in any one of SEQ ID NO:1 and SEQ ID NO:3.

20. A method for producing a Triticeae plant having enhanced resistance to stem rust diseases, the method comprises introducing into at least one cell of a Triticeae plant susceptible to the stem rust diseases a heterologous polynucleotide comprising a nucleic acid sequence encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, thereby producing a Triticeae plant showing a phenotype of enhanced tolerance and / or resistance to said stem rust diseases compared to a corresponding control plant.

21. The method of claim 20, wherein the heterologous polynucleotide encodes at least one polypeptide comprising an amino acid sequence having at least 90% identity to the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NO:3.

22. The method of any one of claims 20-21, wherein the Triticeae plant susceptible to the at least one rust diseases is a Triticeae cultivar suitable for agricultural commercial growth.

23. The method of any one of claims 20-22, wherein the control plant is lacking the heterologous polynucleotide, said control plant is susceptible to the stem rust disease.

24. The method of any one of claims 20-23, wherein introducing the heterologous polynucleotide into the at least one cell comprises transforming the heterologous polynucleotide, a DNA construct, or a vector comprising same into said at least one cell, thereby producing a transgenic plant.

25. The method of any one of claims 20-23, wherein introducing the heterologous polynucleotide into the at least one cell comprises editing the genome of said at least one cell to be capable of expressing the heterologous polynucleotide by gene editing, thereby producing a genetically engineered, non-transgenic plant.

26. The method of any one of claims 20-25, wherein said plant is a wheat plant selected from Triticum turgidum and Triticum aestivum.

1. The method of nay one of claims 20-26, wherein the stem rust disease is caused by the fungus Puccinia graminisf. sp. tritici.

28. A method for selecting a Triticeae plant having an enhanced tolerance and / or resistance to stem rust diseases, comprising the steps of: a. providing a plurality of Triticeae plants each comprising at least one cell comprising a heterologous polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1, wherein the polynucleotide is capable of conferring or enhancing tolerance and / or resistance to the Triticeae plants towards stem rust disease; and b. selecting plants showing an enhanced resistance to said stem rust disease compared to a control Triticeae plant or to a pre-determined resistance score value; thereby selecting a Triticeae plant having enhanced resistance to said stem rust disease.

29. The method of claim 28, wherein the heterologous polynucleotide encodes at least one polypeptide comprising an amino acid sequence having at least 90% identity to the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NO:3.

30. The method of any one of claims 28-29, wherein the control plant is lacking the heterologous polynucleotide, said control plant is susceptible to the stem rust disease.

31. The method of any one of claims 28-30, wherein selecting the plant resistant to the stem rust disease is performed by inoculating the plant with the fungus Puccinia graminisf. sp. tritici and selecting phenotypically resistant plant.

32. The method of any one of claims 28-30, wherein selecting the plant resistantto the stem rust disease is performed by detecting the presence of the heterologous polynucleotide within the genetic material of the at least one cell of the plant.

33. The method of claim 32, wherein detecting the presence of the heterologous polynucleotide is performed by identifying at least one sequence- specific probe that specifically hybridizes under stringent conditions to a nucleic acid sequence having at least 75% identity to the nucleic acid sequence set forth in SEQ ID NO:2 or SEQ ID NO: 4 over its entire length.

34. The method of claim 33, wherein detecting the presence of the heterologous polynucleotide is performed by identifying at least one sequence- specific probe that specifically hybridizes under stringent conditions to a nucleic acid sequence having at least 80% identity to the nucleic acid sequence set forth in SEQ ID NO:5 or SEQ ID NO:6.

35. The method of any one of claims 32-34, wherein detecting the presence of the heterologous polynucleotide is performed by amplifying at least one marker of said heterologous polynucleotide.

36. The method of claim 35, wherein the at least one marker is amplified by a pair of primers comprising SEQ ID NO: 8 and SEQ ID NO:9.

37. The method of claim 36, wherein the marker comprises the nucleic acid sequence set forth in SEQ ID NO:7.

38. The method of claim 35, wherein the at least one marker is amplified by a pair of primers comprising SEQ ID NO: 11 and SEQ ID NO: 12.

39. The method of claim 38, wherein the marker comprises the nucleic acid sequence set forth in SEQ ID NO: 10.

40. The method of any one of claims 28-39, wherein the stem rust disease is caused by the fungus Puccinia graminisf. sp. tritici.

41. An isolated polynucleotide encoding a polypeptide comprising an amino acid sequence having at least 80% identity to the amino acid sequence set forth in SEQ ID NO: 1.

42. The isolated polynucleotide of claim 41 , wherein the polynucleotide encodesat least one polypeptide comprising an amino acid sequence having at least 90% identity to the amino acid sequence set forth in any one of SEQ ID NO: 1 and SEQ ID NO:3.

43. The isolated polynucleotide of any one of claims 41-42, wherein said polynucleotide comprises a nucleic acid sequence having at least 75% identity to the nucleic acid sequence set forth in SEQ ID NO:2 over its entire length.

44. The isolated polynucleotide of claim 43, wherein said polynucleotide comprises a nucleic acid sequence having at least 80% identity to the nucleic acid sequence set forth in SEQ ID NO:5.

45. The isolated polynucleotide of any one of claims 41-42, wherein said polynucleotide comprises a nucleic acid sequence having at least 75% identity to the nucleic acid sequence set forth in SEQ ID NO:4 over its entire length.

46. The isolated polynucleotide of claim 45, wherein said polynucleotide comprises a nucleic acid sequence having at least 80% identity to the nucleic acid sequence set forth in SEQ ID NO: 6.

47. The isolated polynucleotide of any one of claims 41-46, wherein said isolated polynucleotide, when expressed in a Triticeae plant cell, enhances or confers tolerance and / or resistance to stem rust disease.

48. The isolated polynucleotide of claim 47, wherein the stem rust disease is caused by the fungus Puccinia graminisf. sp. tritici.

49. A DNA construct comprising the isolated polynucleotide of any one of claims 41-48, further comprising at least one plant compatible expression regulatory element.

50. A Triticeae plant comprising at least one cell comprising a heterologous polynucleotide encoding a polypeptide having at least 90% identity to the amino acid sequence set forth in SEQ ID NO:3, wherein the heterologous polynucleotide is capable of conferring or enhancing tolerance and / or resistance of the plant to stem rust disease.

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