AUTHOR=Lv Bo , Zheng Lu , Liu Hao , Tang Jintian , Hsiang Tom , Huang Jinbin 

TITLE=Use of Random T-DNA Mutagenesis in Identification of Gene UvPRO1, A Regulator of Conidiation, Stress Response, and Virulence in Ustilaginoidea virens

JOURNAL=Frontiers in Microbiology

VOLUME=7

YEAR=2016

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2016.02086

DOI=10.3389/fmicb.2016.02086

ISSN=1664-302X

ABSTRACT=<p>False smut of rice, caused by <italic>Ustilaginoidea virens</italic> (Cooke) Takahashi (teleomorph: <italic>Villosiclava virens</italic>), is one of the most important diseases affecting rice worldwide. <italic>Agrobacterium tumefaciens</italic>-mediated transformation was used to identify functional genes in <italic>U. virens</italic>. 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 <italic>U. virens</italic>. The <italic>UvPRO1</italic>-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 <italic>UvPRO1</italic> 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 <italic>UvPRO1</italic> 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 <italic>UvPRO1</italic> at 8 dpi was more than twice as high as that at 1–2 dpi. These results suggest that <italic>UvPRO1</italic> 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 <italic>PRO1</italic> protein in fungi and improve the understanding of the function of <italic>UvPRO1</italic> in the life cycle of <italic>U. virens</italic>.</p>