Host-induced gene silencing of the mitogen-activated protein kinase PsFUZ7 confers stable resistance to wheat stripe rust

RNA interference (RNAi) is a powerful genetic tool to accelerate research in plant biotechnology and to control biotic stresses by manipulating target gene expression. However, the potential of RNAi in wheat to efficiently and durably control the devastating stripe rust fungus Puccinia striiformis f. sp. tritici (Pst), remained largely under explored, so far. To address this issue, we generated transgenic wheat lines expressing double-stranded RNA targeting PsFUZ7 transcripts of Pst. We analyzed expression of PsFUZ7 and related genes, and resistance traits of these transgenic wheat lines. We show that PsFUZ7 is an important pathogenicity factor that regulates infection and development of Pst. A PsFUZ7 RNAi construct stably expressed in two independent transgenic lines of wheat confers strong resistance to Pst. Pst hyphal development is strongly restricted, and necrosis of cells in plant resistance responses was induced significantly. We conclude that trafficking of RNA molecules from wheat plants to Pst may lead to a complex molecular dialogue between wheat and the rust pathogen. Moreover, we confirm the RNAi-based crop protection approaches can be used as a novel control strategy against rust pathogens in wheat.