Functional Analysis Of A Putative RhoGAP Protein FgRga2 In Fusarium Graminearum

Fusarium graminearum is a toxin-producing fungal pathogen that can cause fusarium head blight in wheat and other grains,and gibberella ear rot in corn worldwide.Rho family proteins are involved in various cell functions,such as molecular switches in F.graminearum.RhoGTPase activating proteins(RhoGAPs)act as negative regulators of RhoGTPase,participating in a variety of signal transduction pathways during cell development.In order to elucidate the function of FgRga2,one of the RhoGAPs,we generated the FgRGA2 deletion mutant(?Fgrga2-2)by homologous recombination.Our results showed that the?Fgrga2-2 mutant has a reduced growth rate of approximately 20%,a reduced sporulation of approximately 70%,and the yield of DON was reduced dramatically compared with the wildtype PH-1.The ascospores of ?Fgrga2-2 mutant also required more time for maturity.Furthermore,the ?Fgrga2-2 mutant lost virulence on wheat coleoptiles,while the wildtype PH-1 and FgRGA2 overexpression mutants showed typical blight symptom on wheat coleoptiles.There is no interaction between FgRga2 and FgRho1 by yeast two-hybrid.The results of subcellular localization showed FgRga2 locates in cytoplasm.The mycelium growth rate of overexpression mutants showed a little bit higher than the wild type PH-1,and the sensitivity of cell wall of overexpression mutants was increased compared with the PH-1.Taken together,the FgRga2 involves in regulation of development,DON production,sexual reproduction and pathogenicity in F.graminearum.