Wheat stripe resistance genes and method of use

Abstract

Compositions and methods for enhancing the resistance of wheat and barley plants to wheat stripe rust caused by Puccinia striiformis 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 wheat and barley plants to wheat stripe rust comprise introducing a nucleic acid molecule encoding an R gene product into a wheat or barley plant cell. Additionally provided are methods for using the wheat and barley plants in agriculture to limit wheat stripe rust.

1 . An expression cassette or vector comprising a nucleic acid molecule and an operably linked heterologous promoter, wherein the nucleic acid molecule comprises a nucleotide sequence selected from the group consisting of:
 (a) the nucleotide sequence set forth in SEQ ID NO: 1, 2, 5, 7, 9, 11, 15, 34, or 35;   (b) a nucleotide sequence encoding the amino acid sequence set forth in SEQ ID NO: 3, 6, 8, 10, or 12;   (c) a nucleotide sequence having at least 90% nucleotide sequence identity to at least one of the full-length nucleotide sequences set forth in SEQ ID NOS: 1, 2, 5, 7, 9, and 11, wherein the nucleic acid molecule is capable of conferring resistance to wheat stripe rust to a plant comprising the nucleic acid molecule; and   (d) a nucleotide sequence encoding a polypeptide having at least 90% amino acid sequence identity to at least one of the full-length amino acid sequences set forth in SEQ ID NOS: 3, 6, 8, 10, 12, and 14, wherein the nucleic acid molecule is capable of conferring resistance to wheat stripe rust to a plant comprising the nucleic acid molecule.   
     
     
         2 . A host cell transformed with the expression cassette or vector of  claim 1 . 
     
     
         3 . A transgenic plant or seed comprising stably incorporated in its genome a heterologous polynucleotide construct comprising a nucleotide sequence set forth in  claim 1 . 
     
     
         4 . The transgenic plant or seed of  claim 3 , wherein the polynucleotide construct further comprises a promoter operably linked for the expression of the nucleotide sequence in a plant cell. 
     
     
         5 . The transgenic plant or seed of  claim 3 , wherein the transgenic plant is a transgenic wheat plant and the transgenic seed is a transgenic wheat seed. 
     
     
         6 . The transgenic plant or seed of  claim 3 , wherein the transgenic plant is a transgenic barley plant and the transgenic seed is a transgenic barley seed. 
     
     
         7 . The transgenic plant or seed of  claim 3 , wherein the transgenic plant is a transgenic  Brachypodium distachyon  plant and the transgenic seed is a transgenic  Brachypodium distachyon  seed. 
     
     
         8 . A method for producing a plant with enhanced resistance to a rust disease caused by a pathogen in the genus  Puccinia,  the method comprising introducing a heterologous polynucleotide construct into at least one plant cell and regenerating the at least one plant cell into a plant comprising in its genome the heterologous polynucleotide construct, the heterologous polynucleotide construct comprising a nucleotide sequence selected from the group consisting of:
 (a) the nucleotide sequence set forth in SEQ ID NO: 1, 2, 5, 7, 9, or 11;   (b) a nucleotide sequence encoding the amino acid sequence set forth in SEQ ID NO: 3, 6, 8, 10, or 12;   (c) a nucleotide sequence having at least 90% nucleotide sequence identity to at least one of the full-length nucleotide sequences set forth in SEQ ID NOS: 1, 2, 5, 7, 9, and 11, wherein the nucleic acid molecule is capable of conferring resistance to the plant disease to a plant comprising the nucleic acid molecule; and   (d) a nucleotide sequence encoding a polypeptide having at least 90% amino acid sequence identity to at least one of the full-length amino acid sequences set forth in SEQ ID NOS: 3, 6, 8, 10, and 12, wherein the nucleic acid molecule is capable of conferring resistance to the plant disease to a plant comprising the nucleic acid molecule.   
     
     
         9 . The method of  claim 8 , wherein the heterologous polynucleotide construct is stably incorporated into the genome of the plant cell. 
     
     
         10 . The method of  claim 8 , wherein the plant is barley, wheat, or  Brachypodium distachyon.    
     
     
         11 . The method of  claim 10 , wherein the barley, wheat, or  Brachypodium distachyon  plant comprising the heterologous polynucleotide construct comprises enhanced resistance to wheat stripe rust caused by at least one race of  Puccinia striiformis  f. sp.  tritici,  relative to the resistance of a control barley, wheat, or  Brachypodium distachyon  plant. 
     
     
         12 . A method for producing a barley plant with enhanced resistance to wheat stripe rust, the method comprising modifying in a barley plant or at least one cell thereof, a non-functional allele of the resistance gene Rps6 so as to make a functional allele, whereby the resistance of the barley plant to wheat stripe rust is enhanced, wherein the functional allele comprises a nucleotide sequence selected from the group consisting of:
 (a) the nucleotide sequence set forth in SEQ ID NO: 1; and   (b) a nucleotide sequence having at least 95% nucleotide sequence identity to the full-length nucleotide sequence set forth in SEQ ID NO: 1.   
     
     
         13 . The method of  claim 12 , wherein said modifying a non-functional allele comprises introducing at least one genetic modification selected from the group consisting of an insertion, a deletion, and a substitution of at least one base pair in the non-functional allele. 
     
     
         14 . The method of  claim 12 , wherein said modifying a non-functional allele comprises at least one member selected from the group consisting of targeted mutagenesis, homologous recombination, and mutation breeding. 
     
     
         15 . A method of limiting wheat stripe rust in agricultural crop production, the method comprising planting the transgenic seed of  claim 3  and growing from the transgenic seed a plant under conditions favorable for the growth and development of the plant. 
     
     
         16 . A human or animal food product produced using the transgenic plant or seed of  claim 3 . 
     
     
         17 . A method for identifying a wheat or barley plant comprising a resistance (R) gene against wheat stripe rust, the method comprising detecting in the wheat or barley plant the presence of an R gene comprising a nucleotide sequence set forth in  claim 1 . 
     
     
         18 . The method of  claim 17 , wherein the presence of the R gene is detected by detecting in the wheat or barley plant the entire R gene, at least one marker within the R gene or, or the R protein encoded by the R gene. 
     
     
         19 . The method of  claim 18 , wherein detecting the presence of the at least one 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.