Submitted to: Plant and Animal Genome VX Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 12/1/2004
Publication Date: 1/1/2005
Citation: Ling, P., Chen, X., Le, D.Q., Garland Campbell, K.A. 2005. Towards cloning of the yr5 gene for resistance to stripe rust. Plant and Animal Genome Abstracts. Vol 13, pg 97.
Technical Abstract: The Yr5 gene confers resistance to all races of the wheat stripe rust pathogen (Puccinia striiformis f. sp. tritici). Markers co-segregating with Yr5 and having sequence homology to resistance genes have been previously identified. To clone Yr5, a hexapod wheat BAC library was constructed using the genomic DNA of the Yr5 near isogonics line (NIL) digested with HindIII. The BAC library consists of 410,000 clones with an average insert size of 13kb, and covers approximately 3.3x wheat genome equivalents. To facilitate rapid screening, the library was divided into 11 primary pools, and each contained 38,400 clones. Each primary pool was further ranged into sub-primary pools in a 3D arrangement. The BAC clones were cultured as matrix and DNA was extracted for screening. Three Yr5-specific markers were used to screen the BAC library. We identified 12 positive BAC clones. In order to reveal the physical relatedness of the individual clones, DNA fingerprints of the positive clones were generated. HindIII fragments of the positive BAC clones were hybridized using the STS7/8 marker as probes. Sub-cloning of the positive clones is currently undertaken. To isolate the expressed the sequences from the Yr5 locus region, we constructed full-length cDNA library from the pathogen challenged Yr5 NIL. The full-length cDNA library consists of approximately 42,000 clones, with an average cDNA length of 1.5kb. Screening the full-length cDNA library is being conducted using the Yr5 STS markers.