The transcription factor UvCreA regulates ustilaginoidin synthesis and pathogenicity in Ustilaginoidea virens

Ustilaginoidea virens generates several types of mycotoxins, including ustilaginoidins during infection. The transcription factor CreA plays a central role in carbon catabolite repression, coordinating carbon source utilization during fungal growth, development, and host infection. However, knowledge is limited regarding the specific functions and molecular mechanisms by which CreA regulates mycotoxin biosynthesis and pathogenicity. In this study, we found that the wild-type U. virens strain exhibited significantly different ustilaginoidin-producing capacities under distinct carbon sources. The UvCreA gene knockout mutants exhibited slowed mycelial growth, decreased pathogenicity and ustilaginoidin production, but produced significantly more conidiospores than the wild type. Consistently, the expression of ustilaginoidin biosynthetic genes was significantly down-regulated in the UvCreA mutant. Moreover, yeast one-hybrid and electrophoretic mobility shift assays confirmed that UvCreA binds to the promoter regions of polyketide synthase gene UvPKS1 and methyltransferase gene UgsJ . ChIP-qPCR showed significant enrichment in promoter regions of UvPKS1 and UgsJ . These findings indicate that UvCreA not only controls ustilaginoidin biosynthesis through directly binding the Ugs gene promoters, but also positively regulates mycelium growth and pathogenicity in U. virens . Therefore, this study provides theoretical insights into the mechanisms of carbon metabolism and mycotoxin biosynthesis in phytopathogenic fungi.