Molecular Mapping Of A Wheat Stripe Rust Resistance Gene In Chinese Differential Host JubilejinaⅡ

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a worldwide disease and oneof the most destructive diseases in wheat, especially in China, which is the biggest epidemic zone in theworld. Pst is obligated fungi, its sexual stage was found recently, but now the only way to identificationdifferent races is by a set of differential hosts. The research and analysis in the characterizations ofresistance genes and gene mapping could help the further research in interaction between resistancegenes and avirulence genes of Pst. Jubilejina Ⅱ is a differential host in China with a special ability todistinguish some wheat stripe rust, so the mapping of resistance genes in Jubilejina Ⅱ is of greattheoretical and applied importance.By gene postulation analysis, general hybridization genetic analysis and SSR molecular markermethods, the resistance gene in near-isogenic lines Mingxian169*6/Jubilejina Ⅱ, in which Mingxian169as a recurrent parent and Jubilejina Ⅱ as a gene donor parent, was analyzed and mapped.Gene postulation showed that the resistance spectrum of8lines (N1, N2, N6, N9, N11, N13, N17,N19) of Mingxian169*6/Jubilejina Ⅱ to all test races was narrower than that of Jubilejina Ⅱ, indicatingthat the four genes of Jubilejina Ⅱ were unwrapped in the process of transferring, and the8lines wereclassified into4categories. According to the resistance spectrum and agronomic traits, N9from8lineswas chosen to analyze the resistance inheritance and gene location.Based on general hybridization genetic analysis, NIL N9was crossed with the recurrent cultivarMingxian169to obtain F1and F1was self-pollinated to get the F2population. The infection type of N9,Mingxian169, F1and F2population to CYR17was record and analyzed. The results showed that thestripe rust resistance in N9of Mingxian169*6/Jubilejina Ⅱ to CYR17was controlled by a singledominant gene.With SSR molecular marker,566pairs of primers on the21wheat chromosomes were randomlyselected to analyze the polymorphisms between N9, Mingxian169and Jubilejina Ⅱ. The results showedthat there are stably polymorphisms bands between N9and Mingxian169amplified by the primersXwmc170, Xcfa2043, Xgwm388, Xbarc160, Xbarc91, Xwmc245, Xwmc592, Xwmc317, andXgpw4170. Further analysis showed Xwmc170and Xcfa2043were linked to the resistance gene in N9,which was a new stripe rust resistance on the wheat2AL chromosome and temporary designated asYr53. The genetic distance of Yr53to primers Xwmc170and Xcfa2043were0.5cM and6.2cM, andwas near the centromere. The order of Yr53and marker on wheat2AL is: centromere-Yr53-Xwmc170-Xcfa2043.