Use of Random T-DNA Mutagenesis in Identification of Gene , A Regulator of Conidiation, Stress Response, and Virulence in .

False smut of rice, caused by (Cooke) Takahashi (teleomorph: ), is one of the most important diseases affecting rice worldwide. -mediated transformation was used to identify functional genes in . In this study, we selected a single-copy insertion mutant T133 with deficiency in producing conidia by screening the T-DNA insertion mutant library of . The -deletion mutant was successfully obtained after cloning the targeted gene by analysis of the T-DNA insert site of mutant T133. Further research showed that the mutant was reduced in growth rate and could not produce conidia in PSB medium, while sensitivities to sodium dodecyl sulfate, Congo red, and hyperosmotic stress increased. Moreover, the deletion mutant hyphae could extend along the surface of spikelets at 1-3 dpi, but mycelia became shriveled and completely lost the ability to infect spikelets at 4 dpi. The relative expression level of at 8 dpi was more than twice as high as that at 1-2 dpi. These results suggest that plays a critical role in hyphal growth and conidiation, as well as in stress response and pathogenesis. These findings provide a novel mode of action for the protein in fungi and improve the understanding of the function of in the life cycle of .