Transcription Factor Negatively Regulates Conidiation by Affecting Utilization of Carbon and Nitrogen Source in .

Conidium is the main infection unit and reproductive unit of pathogenic fungi. Exploring the mechanism of conidiation and its regulation contributes to understanding the pathogenicity of pathogenic fungi. , a transcription factor, was reported to participate in the conidiation process. However, the regulation mechanism of in conidiation is still unclear. In this study, we analyzed the function of and its regulation mechanism in conidiation through knocking out and overexpression of in entomopathogenic fungus . Results showed that the colonial growth of disruption mutant (Δ) was significantly decreased, and conidiation was earlier compared to wild type (WT), while overexpression of led to a delayed conidiation especially when carbon or nitrogen sources were insufficient. Overexpression of resulted in a conidiation pattern shift from microcycle conidiation to normal conidiation on nutrient-limited medium. These results indicated that Mavib-1 acted as a positive regulator in vegetative growth and a negative regulator in conidiation by affecting utilization of carbon and nitrogen sources in . Transcription profile analysis demonstrated that many genes related to carbon and nitrogen source metabolisms were differentially expressed in Δ and OE strains compared to WT. Moreover, affects the conidial germination, tolerance to UV-B and heat stresses, cell wall integrity, conidial surface morphology and conidial hydrophobicity in . These findings unravel the regulatory mechanism of in fungal growth and conidiation, and enrich the knowledge to conidiation pattern shift of filamentous fungi.