The Highly Conserved Barley Powdery Mildew Effector Confers Susceptibility to Biotrophic and Necrotrophic Pathogens in Wheat.

Effector proteins secreted by plant pathogens play important roles in promoting colonization. effector candidate () 1019, a highly conserved metalloprotease of f. sp. (), is essential for fungal haustorium formation, and silencing significantly reduces virulence. In this study, we found that homologs in f. sp. () and var. () have complete sequence identity with those in , prompting us to investigate their functions. Transcript levels of were abundantly induced concomitant with haustorium formation in and necrosis development in -infected plants. overexpression considerably increased wheat susceptibility to and , whereas silencing this gene using host-induced gene silencing significantly enhanced wheat resistance to and , which was associated with hydrogen peroxide accumulation, cell death, and pathogenesis-related gene expression. Additionally, we found that the full and partial sequences of can trigger cell death in leaves. These results indicate that and can utilize as a virulence effector to promote plant colonization, and thus these genes represent promising new targets in breeding wheat cultivars with broad-spectrum resistance.