Host-Induced Gene Silencing of a G Protein α Subunit Gene Involved in Pathogen Appressoria Formation and Virulence Improves Tobacco Resistance to .

Hypertrophy sorosis scleroteniosis caused by is the most devastating disease of mulberry fruit. However, few mulberry lines show any resistance to . An increasing amount of research has shown that host-induced gene silencing (HIGS) is an effective strategy for enhancing plant tolerance to pathogens by silencing genes required for their pathogenicity. In this study, two G protein α subunit genes, and , were identified from Silencing and had no effect on hyphal growth but reduced the number of sclerotia and increased the single sclerotium weight. Moreover, silencing resulted in increased fungal resistance to osmotic and oxidative stresses. Compared with wild-type and empty vector strains, the number of appressoria was clearly lower in strains. Importantly, infection assays revealed that the virulence of strains was significantly reduced, which was accompanied by formation of fewer appressoria and decreased expression of several cAMP/PKA- or mitogen-activated protein-kinase-related genes. Additionally, transgenic expressing double-stranded RNA targeted to through the HIGS method significantly improved resistance to . Our results indicate that is an important regulator in appressoria formation and the pathogenicity of . is an efficient target to improve tolerance to using HIGS technology.