Wheat stem rust resistance genes and methods of use

Abstract

Compositions and methods and for enhancing the resistance of wheat plants to wheat stem rust caused by Puccinia graminis f sp. tritici are provided. The compositions comprise nucleic acid molecules encoding resistance (R) gene products and variants thereof and plants, seeds, and plant cells comprising such nucleic acid molecules. The methods for enhancing the resistance of a wheat plant to wheat stem rust comprise introducing a nucleic acid molecule encoding an R gene product into a wheat plant cell. Additionally provided are methods for using the wheat plants in agriculture to limit wheat stem rust.

That which is claimed: 
     
         1 . A method for identifying a wheat plant that is expected to display enhanced resistance to wheat stem rust, the method comprising detecting in the wheat plant the presence of an R gene, wherein the R gene comprises a nucleotide sequence selected from the group consisting of:
 (a) the nucleotide sequence set forth in SEQ ID NO: 1, 4, 7, 10, 19, 22, or 25;   (b) a nucleotide sequence encoding the amino acid sequence set forth in SEQ ID NO: 2, 5, 8, 11, 20, 23, or 26;   (c) the nucleotide sequence set forth in SEQ ID NO: 3, 6, 9, 12, 21, 24, or 27;   (d) a nucleotide sequence having at least 90% sequence identity to at least one of the nucleotide sequences set forth in (a) or (c), wherein the R gene is capable of conferring resistance to stem rust to a wheat plant comprising the R gene; and   (e) a nucleotide sequence encoding an amino acid sequence having at least 90% sequence identity to at least one amino acid sequence set forth in (b), wherein the R gene is capable of conferring resistance to stem rust to a wheat plant comprising the R gene.   
     
     
         2 . The method of  claim 1 , wherein detecting the presence of the R gene comprises a member selected from the group consisting of PCR amplification, nucleic acid sequencing, nucleic acid hybridization, and an immunological assay for the detection of the R protein encoded by the R gene. 
     
     
         3 . The method of  claim 2 , wherein the presence of the R gene is detected by detecting at least one DNA marker within the R gene. 
     
     
         4 . The method of  claim 1 , wherein the R gene comprises the nucleotide sequence set forth in SEQ ID NO: 1, 4, 7, 10, 19, 22, or 25. 
     
     
         5 . An expression cassette or vector comprising a nucleotide sequence selected from the group consisting of:
 (a) the nucleotide sequence set forth in SEQ ID NO: 1, 4, 7, 10, 19, 22, or 25;   (b) a nucleotide sequence encoding the amino acid sequence set forth in SEQ ID NO: 2, 5, 8, 11, 20, 23, or 26;   (c) the nucleotide sequence set forth in SEQ ID NO: 3, 6, 9, 12, 21, 24, or 27;   (d) a nucleotide sequence having at least 90% sequence identity to at least one of the nucleotide sequences set forth in (a) or (c), wherein the nucleic acid molecule is capable of conferring resistance to stem rust to a wheat plant comprising the nucleic acid molecule; and   (e) a nucleotide sequence encoding an amino acid sequence having at least 90% sequence identity to at least one amino acid sequence set forth in (b), wherein the nucleic acid molecule is capable of conferring resistance to stem rust to a wheat plant comprising the nucleic acid molecule.   
     
     
         6 . The expression cassette or vector of  claim 5 , further comprising an additional wheat stem rust resistance gene. 
     
     
         7 . The expression cassette or vector of  claim 6 , wherein the additional wheat stem rust resistance gene is selected from the group consisting of Sr26, Sr32, Sr33, Sr39, Sr40, Sr45, Sr47, and Sr50. 
     
     
         8 . A host cell transformed with the expression cassette or vector of  claim 5 . 
     
     
         9 . A plant or a seed transformed with the expression cassette or vector of claim  claim 5 . 
     
     
         10 . A human or animal food product produced using the wheat plant or seed of  claim 9 . 
     
     
         11 . A method for enhancing the resistance of a wheat plant to wheat stem rust, the method comprising introducing a polynucleotide into at least one wheat plant cell, the polynucleotide comprising a nucleotide sequence selected from the group consisting of:
 (a) the nucleotide sequence set forth in SEQ ID NO: 1, 4, 7, 10, 19, 22, or 25;   (b) a nucleotide sequence encoding the amino acid sequence set forth in SEQ ID NO: 2, 5, 8, 11, 20, 23, or 26;   (c) the nucleotide sequence set forth in SEQ ID NO: 3, 6, 9, 12, 21, 24, or 27;   (d) a nucleotide sequence having at least 90% sequence identity to at least one of the nucleotide sequences set forth in (a) or (c), wherein the polynucleotide is capable of conferring resistance to stem rust to a wheat plant comprising the polynucleotide; and   (e) a nucleotide sequence encoding an amino acid sequence having at least 90% sequence identity to at least one amino acid sequence set forth in (b), wherein the polynucleotide is capable of conferring resistance to stem rust to a wheat plant comprising the polynucleotide.   
     
     
         12 . The method of  claim 11 , wherein the polynucleotide is stably incorporated into the genome of the plant cell. 
     
     
         13 . The method of  claim 12 , wherein the wheat plant cell is regenerated into a wheat plant comprising in its genome the polynucleotide. 
     
     
         14 . The method of  claim 11 , wherein the polynucleotide comprises the nucleotide sequence of any one of (b)-(e) and further comprises a promoter operably linked for the expression of the nucleotide sequence in a plant. 
     
     
         15 . The method of  claim 14 , wherein the promoter is selected from the group consisting of pathogen-inducible, constitutive, tissue-preferred, wound-inducible, and chemical-regulated promoters. 
     
     
         16 . The method of  claim 11 , wherein the wheat plant comprising the polynucleotide comprises enhanced resistance to wheat stem rust caused by at least one race of  Puccinia graminis  f sp.  tritici , relative to a control wheat plant. 
     
     
         17 . The method of  claim 11 , wherein the polynucleotide construct comprises at least two nucleotide sequences encoding an R protein for wheat stem rust. 
     
     
         18 . The method of  claim 17 , wherein each of the at least two nucleotide sequences encoding an R protein for wheat stem rust encodes a different R protein for wheat stem rust. 
     
     
         19 . A wheat plant produced by the method of  claim 11 . 
     
     
         20 . A seed of the wheat plant of  claim 19 , wherein the seed comprises the polynucleotide. 
     
     
         21 . A human or animal food product produced using the seed of  claim 20  or a plant grown from the seed, wherein the food product comprises the polynucleotide.