Quantitative Proteomics Analysis Reveals the Function of the Putative Ester Cyclase UvEC1 in the Pathogenicity of the Rice False Smut Fungus Ustilaginoidea virens

Abstract

Rice false smut is a fungal disease distributed worldwide and caused by <i>Ustilaginoidea virens</i>. In this study, we identified a putative ester cyclase (named as UvEC1) as being significantly upregulated during <i>U. virens</i> infection. UvEC1 contained a SnoaL-like polyketide cyclase domain, but the functions of ketone cyclases such as SnoaL in plant fungal pathogens remain unclear. Deletion of <i>UvEC1</i> caused defects in vegetative growth and conidiation. <i>UvEC1</i> was also required for response to hyperosmotic and oxidative stresses and for maintenance of cell wall integrity. Importantly, Δ<i>UvEC1</i> mutants exhibited reduced virulence. We performed a tandem mass tag (TMT)-based quantitative proteomic analysis to identify differentially accumulating proteins (DAPs) between the Δ<i>UvEC1-1</i> mutant and the wild-type isolate HWD-2. Proteomics data revealed that UvEC1 has a variety of effects on metabolism, protein localization, catalytic activity, binding, toxin biosynthesis and the spliceosome. Taken together, our findings suggest that <i>UvEC1</i> is critical for the development and virulence of <i>U. virens</i>.