| Stripe rust caused by Puccinia striiformis f. sp. tritici（Pst）, is a destructive foliar fungal disease posing a grave threat to wheat production worldwide. It can reduce 20%30% of yield in normal epidemic years, and even 50%60% in severe epidemic years. Chemicals have been taken to reduce the damage; however, this leads to environmental pollution and acquisition of fungicide tolerance by pathogens. Therefore, growing resistant cultivars is considered the most economical and environmentally friendly strategy to control the disease. To explore novel resistant materials and genes and identify molecular markers linked with these genes are of great importance to breed durable resistant wheat cultivars. In the present study, we constructed several genetic populations based on three resistant wheat cultivars and three susceptible cultivars, in combination with BSA（Bulked segregant analysis）, Wheat iSelect 90 K SNP array,SSR and EST markers to map resistance genes. The main results are as follows:1. Genetic mapping of stripe rust resistance gene in the northern winter wheat region leading cultivar Zhongmai 175The prevalent Pst race CYR29 was used to test seedling resistanc of F1, F2 and F2:3 populations derived from a cross of Lunxuan 987/Zhongmai 175. Genetic analysis indicated that Zhongmai 175 possessed a dominant resistance gene to CYR29, tentatively designated YrZM175. Resistant and susceptible bulks from F2 population were screened by Wheat iSelect 90 K SNP array to determine a preliminary location of YrZM175. Subsequently, SSR, EST and SNP-derived KASP markers were screened through BSA and polymorphic markers on the specific chromosome were used for genotyping the F2 population, and finally five SSR, one EST and two KASP markers linked with YrZM175 were detected. Among them, the markers flanking YrZM175 were Xgwm636 and Xwmc382, at genetic distances of 4.9 and 8.1 cM, respectively. Chinese Spring（CS）, Chinese Spring nulli-tetrasomic, nulli-tetrasomic ditelosomic（Dt2AS） and 2AS deletion lines were used to verify locations of flanked markers, demonstrating that YrZM175 was located on 2AS5-0.78-1.00. Analysis of pedigree, resistance spectrum and molecular markers test indicated that YrZM175 was a novel stripe rust resistance gene different from other Yr genes on chromosome 2AS, viz. Yr17, Yr56, YrR61 and Yr69.2. Genetic mapping of stripe rust resistance gene in wheat line 8927ⅦSeedling test showed that the common wheat line 8927Ⅶ conferred a high level of resistance to 23 Pst races or isolates except V26. The prevalent Pst race CYR32 was used to test seedlings of F1, F2 and F2:3 populations developed from the Huixianhong/8927Ⅶ cross. Genetic analysis indicated that 8927Ⅶ carried a dominant resistance gene to CYR32, temporarily designated Yr8927Ⅶ. Wheat iSelect 90 K SNP array was used to screen polymorphic markers between resistant and susceptible bulks constructed from F2 population, and Yr8927Ⅶ was preliminarily located on chromosome 1B. The two parents and two bulks were subsequently used to screen SSR and EST markers on chromosome 1B, resulting seven markers linked with Yr8927Ⅶ. The closely linked marker to Yr8927Ⅶ was Xbarc120, at genetic distances of 6.2 cM. Further pedigree and resistance spectrum analysis demonstrated that Yr8927Ⅶ differed from reported formally named stripe rust resistance genes Yr3 a, Yr3 b, Yr9, Yr10, Yr15, Yr24/Yr26, Yr29, Yr64 and Yr65 on chromosome 1B, and it is likely to be a new resistance gene. 3. Genetic analysis of resistance in Huanghuai wheat region leading cultivar Zhengmai 366Seedling test to Pst races or isolates showed that Zhengmai 366 conferred a high level of resistance to all Chinese Pst races apart from CYR31. Zhengmai 366 was crossed to Avocet S to establish F1 and F2 populations, which were inoculated by the prevalent race CYR29. Seedling resistance analysis exhibited that the stripe rust resistance in Zhengmai 366 was conferred by a dominant gene and a recessive gene. |
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