Virulence characteristics of Blumeria graminis f. sp. tritici and its genetic diversity by EST-SSR analyses.

Wheat powdery mildew, caused by f. sp. (an obligate biotrophic pathogen) is a worldwide threat to wheat production that occurs over a wide geographic area in China. For monitoring genetic variation and virulence structure of f. sp. in Liaoning, Heilongjiang, and Sichuan in 2015, 31 wheat lines with known Powdery mildew resistance genes and 2 EST-SSR markers were used to characterize the virulence and genetic diversity. Results indicated that 90% of all isolates were virulent on , , , , , (Timgalen), , , , and and 62.6% to 89.9% of isolates were virulent on , , , , (Coker747), , , , , , , , , , , . The and genes were effective against most collected isolates from Liaoning and Heilongjiang Provinces. Only exhibited an immune infection response to all isolates. Furthermore, closely related isolates within each region were distinguished by cluster analyses using EST-SSR representing some gene exchanges and genetic relationships between the flora in Northeast China (Liaoning, Heilongjiang) and Sichuan. Only 45% of the isolates tested show a clear correlation between EST-SSR genetic polymorphisms and the frequency of virulence gene data. However, the EST-SSR polymorphism of isolated genes did not correspond to the virulence diversity of isolates in the single-gene lineage identification of hosts.