Molecular Marker Development And Localization Of The Stripe Rust Resistance Gene Yr1 In Chinese166

Wheat stripe rust, caused by Puccinia striiformis West. f. sp. Tritici (PST), is one of the most destructive diseases on wheat in many wheat-grown regions in the world,and it is especially heavy and popular in China. Puccinia striiformis is a specific fungus on wheat and its perfect stage has not yet been found .Therefore it is the only method to use host resistance genes to identify the pathogens'virulent genes. After finding out the genetic characteristics, markers and chromosome localization of stripe rust resistance genes, we can improve research levels of pathogens'specificity and host resistance gene analysis. Chinese166 is a very important international wheat stripe rust differential host containing the stripe rust resistance gene Yr1 which exists in many Chinese cultivars. Molecular marker development and chromosome localization for Yr1 is of great theoretical and practice sense.Conventional genetic analysis and SSR were used to develop markers linked closely with Yr1 and to localize it on chromosome genetic map in present study. We analyzed the Taichang29*6/Yr1 near isogenic line (NIL) N1 through crossing the Yr1 gene donor Chinese166 with susceptible recurrent cultivar Taichang29 with pathotype 2E16 of P. striiformis. Through seedling resistance identification of F2 population, the results showed that 181 lines were resistant and 64 were susceptible, and the ratio of resistance lines to susceptible ones was 3R:1S. We also tested the 45-line BC1 population and 1560-line F3 population and further confirmed that the resistance to 2E16 in Taichung29*6/Yr1 N1 line was only controlled under only one dominant gene.Yr1 has been identified to be on wheat 2A Chromosome, 120 SSR primers on 2A were used to test the polymorphisms among Taichung29*6/Yr1 NILs, the recurrent parent Taichung29 and resistance gene donor Chinese166 in this research. The results showed that different DNA bands between NIL, Chinese166 and Taichang29 were produced by PCR amplification with three markers Xgwm311, Xgwm382 and Xcfa2086 and the those markers were further confirmed to be linked with Yr1 by a F2 population.We tested Xgwm311, Xgwm382 and Xcfa2086 on 245 lines of Taichung29*6/Yr1 F2 population through PCR amplification and PAGE electrophoresis. Based on the analysis results of DNA band types and corresponding resistance phenotypes of the 200 F2 lines with software Mapmaker3.0b, the genetic distance between molecular marker and Yr1 were 5.6cM, 1.2cM and 11.4cM respectively, and we proposed that the resistance gene Yr1 was at the position of Cent—Xcfa2086—10.2cM—Xgwm382—1.2cM—Yr1—5.6cM —Xgwm311 on wheat chromosome 2AL in wheat SSR genetic map.We also tested a new method MFLP on wheat. The result showed that it can produce more polymorphisms on wheat genome. So it can be used to develop molecular markers and to identify genetic polymorphism among wheat varieties.