Research Of Popuiation Structure And Genetic Diversity Of Puccinia Striifofmis F.sp.Tritici In Shaanxi,Hubei And Henan Province

Wheat stripe rust is the global important fungal diseases caused by Puccinia striiformis f.sp.tritici(Pst).Wheat stripe rust occurs in all wheat planting areas in China,especially in the Northwest and Southwest wheat planting regions.Due to the temperature-sensitive characteristic of stripe rust,it needs different oversummering and overwintering geographical regions to complete the annual cycle.Shaanxi,Hubei and Henan are the mian overwintering zones of stripe rust,are also as “bridge areas” where stripe rust spread from the west oversummering areas to the east and the north.As a result,stripe rust frequently occurs in these areas,seriously threatening the safe production of wheat.Systematic monitoring of the population structure and genetic diversities of wheat stripe rust in these regions is an indispensable basic research work in disease prevention and control,It provides the most basic information for the study of inter-regional disease epidemics,resistance breeding,rational use of varieties,and the formulation and implementation of comprehensive prevention and control strategies and measures.In this research,we have completed the monitoring of Pst races on 150 Pst samples come from Shaanxi,Hubei and Henan province by using Chinese differentials.15 pairs of Pst specific simple-sequence repeat(SSR)primers were used to analysis molecular polymorphism on 241 samples,isolates from Ningqiang experiment were collected in 2014,Longxian,Nanyang,Jingzhou and Yicheng samples were collected in 2015,The results were obtained as follows:1.A total of 22 physiological races were identified in 2015 and 2016 isolates,dominant races were CYR32,CYR33,CYR34 and G22-14,dominant populations were Suwon11 group,Hybrid46 group and Guinong22 group.All isolates could not infect ZhongSi and T.spelta.album,Besides the virulence to Hybrid46(Yr3b/ Yr4b)and Guinong22(Yr26)is less than 40%,most isolates has stable and high frequency of virulence to most of the Chinese differentials.2.Niangqiang,Yicheng and Jingzhou stripe rust populations were different groups,and had different genetic backgrounds between groups;The genetic differentiation of the stripe rust population in Longxian,Nanyang and Jingzhou experiment was not obvious,and there was a relatively wide gene flow,suggesting that stripe rust between the regionals exist frequent exchanges.3.The stripe rust populations in Ningqiang,Longxian,Nanyang,Jingzhou and Yicheng had high genetic diversity,among which the stripe rust population in Ningqiang had the highest level of diversity(I,0.94;H,0.49),Jingzhou had the lowest level of diversity(I,0.67;H,0.38).Besides Jingzhou Pst population,the other four experiments Pst populations had an excess of observed heterozygosity,indicating that the Pst populations in those areas were clonal.4.Wheat varieties have a selective effect on the Puccinia striiformis f.sp.tritici,and wheat varieties are an important factor affecting the population structure of stripe rust.