Submitted to: APS Annual Meeting
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2008
Publication Date: 6/1/2008
Citation: Wang, M., Coram, T., Chen, X., Boyd, L., Ling, P. 2008. High-resolution genetic and physical mapping of the Yr5 gene for resistance to stripe rust of wheat. Phyto 98-S166.
Technical Abstract: Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a destructive disease of wheat worldwide. The Yr5 gene confers resistance to all races of the pathogen identified so far in the US. To clone Yr5, an F2 segregating population consisting of 1400 plants from a cross between the susceptible cultivar ‘Avocet S’ and a Yr5 resistant near-isogenic line (NIL) in the ‘Avocet S’ background was phenotyped for stripe rust reactions using race PST-43. A fine genetic map of the Yr5 locus was constructed using resistance gene analog polymorphism (RGAP), sequence tagged site (STS), and bacterial artificial chromosome (BAC) end markers. These markers spanned the Yr5 locus within a 0.7cM genetic interval. The most closely linked marker was 0.14cM from the Yr5 locus. The genomic BAC library of the Yr5 NIL was screened using the flanking markers STS7/8, STSuk1, and STSuk2. Six BAC clones were identified by the two closest markers and three more BAC clones were identified by one step of chromosome walking towards the Yr5 locus. The nine BAC clones consist of a physical contig of about 400kb spanning the Yr5 locus corresponding to a 0.19cM genetic interval. Three RGAs were identified in this region, which were highly homologous with resistance proteins in rice chromosome 4 belonging to the nucleotide binding site-leucine rich repeat (NBS-LRR) class. The results indicate that Yr5 is located in a resistance gene cluster on chromosome 2BL.