Molecular mapping of a stripe rust resistance gene in Chinese wheat landrace “Hejiangyizai” using SSR, RGAP, TRAP, and SRAP markers

Stripe rust, which is caused by the biotrophic fungus Puccinia striiformis f. sp. tritici (Pst), is one of the most challenging fungal diseases affecting wheat (Triticum aestivum L.), because specific virulent races often overcome host resistance genes. There is a continuous demand for new host resistance genes that are effective against such races. Chinese wheat landrace, which is the primary gene pool of the common wheat, is a valuable source of novel stripe rust resistance genes for wheat breeding. Chinese wheat landrace 'Hejiangyizai' (HY) is highly resistant to a wide spectrum of Chinese Pst races in both seedling and adult-plant stages. Genetic analysis has indicated that a single dominant gene in HY confers resistance to stripe rust, which has been temporarily designated as YrHY. Segregation of the F2 population and its F2:3 families derived from the cross between HY and Taichung 29 was used for bulked segregant analysis using simple sequence repeats (SSRs), resistance gene analog polymorphisms (RGAPs), sequence-related amplified polymorphisms (SRAPs), and target region amplified polymorphisms (TRAPs). Linkage analysis indicated that six SSR, eight RGAP, two TRAP, and six SRAP polymorphic markers were linked to the stripe rust resistance gene YrHY. The two closest flanking SSR markers were Xbarc92 and Xcfd66, with genetic distances of 4.3 and 8.5 cM, respectively. YrHY was physically mapped to chromosome 7DS using a set of Chinese spring nullisomic-tetrasomic lines. Comprehensive analyses of the seedling and adult reaction patterns of HY tested whit Chinese PST race CYR32, allelic test, and pedigree relationship indicated that YrHY differed from Yr18, Yr33, YrY201, YrY212, and YrWV on chromosome 7D. These results demonstrated that the YrHY may be a novel stripe rust resistance gene.