Populations Virulence And Molecular Analysis Of Puccinia Striiformis F.SP.Tritici At Different Altitudes And Different Wheat Cultivar In South Gansu,China

Wheat stripe rust,one of the most destructive diseases,caused heavy losses on wheat production in China in epidemic years.The pathogen,Puccinia striiformis f.sp.tritici(Pst),is an obligate biotrophic parasite and reproduce only in living plant tissue with high virulence variability,and the virulence variability is the major reason for disease outbreak again.The Longnan regions in Gansu Province is the major over-summering regions for the pathogen and key epidemiological zones in Northwest China.It is important to control the disease effectively by knowing the virulence structure and epidemic rules of Pst,and to research the population genetic diversity of Pst in different altitude regions of Longnan.In this study,total 256 isolates were collected on 5 wheat varieties growing in 3 different altitude regions(high mountain,mid-mountain and low mountain)in two season crops of wheat growing,first is spring crop on 2015 of May,second is winter crop on November in the same year.Isolates virulence were characterized by 27 single Yr gene ence repeat(SSR)markers.Our virulence and molecular data showed that1.The virulence frequency of spring crop,total 128 isolate reached 62 phenotypes,the phenotype number of ph1,ph2,ph3,ph4,ph5,ph6 and ph7 were the predominant,accounted more than 40%.The virulence frequency of autumn crop,total 62 isolate reached 24 phenotypes,the predominant were ph1,ph2,ph3 and ph4,accounted more than 40%.On two season crop the independent phenotype were 45.2% and 37.2% respectively.The data analysis shows that wheat cultivar of LT17,XY22 and ZM9023 the individual phenotype were more than LT19 and MX9023.For the predominant phenotype in the endemic regions,the proportion of the pathogenic gene in the population is large,it can infect all resistant varieties,need to pay attention on the prevention and control of wheat strip rust in the future.2.The virulence diversity in spring crop,different altitude,in XBZ the wheat cultivar of LT17 was the most abundant(K=0,22),follow by GP wheat cultivar of MX169,ZM9023 and LT19 was 0.20.and in FH wheat cultivar of LT17 was the lowest(K= 0,04).In winter crop,PN wheat cultivar of LT17 the virulence diversity was the highest(K= 0.11),GP wheat cultivar of ZM9023 was the lowest(K=0.005).Indicate that,population virulence diversity in different wheat cultivars at different altitude and different wheat cultivars at same altitude have significant differences(α=0.05)3.The genetic diversity analysis,spring crop,in XBZ wheat cultivar of LT17 the genetic diversity was the most abundant(H=0.24,I=0.37),follow by XBZ wheat cultivar of MX169 and ZM9023(H=0.22,I= 0.33),follow by PN wheat cultivar of ZM9023 was the lowest(H=0.06,I=0.10).Autumn crop,in LJP was the most abundant of genetic diversity(H=0.27,I=0.41),follow by GP wheat cultivar of MX169 and LT19(H=0.24,I=0.36),in PN wheat cultivar of ZM9023 and LT17 genetic diversity was lowest(H= 0.06,I= 0.10 and H= 0.09,I= 0.14).Indicate that,population virulence diversity in different wheat cultivars at different altitude and different wheat cultivars at same altitude have significant differences.4.Virulence and Genetic analysis evidences revealed,population of wheat strip rust in different wheat cultivars at different altitude and different wheat cultivars at same altitude have significant differences,the virulence diversity was abundant,the virulence diversity high mountainous area is much higher than mountainside area or lowlands in spring crop,and virulence diversity of mountainside area is higher than high mountain area on winter crop.The results of this study will provide basic guidance for the effective prevention and control wheat stripe rust.