A novel transcription factor UvCGBP1 regulates development and virulence of rice false smut fungus Ustilaginoidea virens

摘要

Ustilaginoidea virens , causing rice false smut (RFS) is an economically important ascomycetous fungal pathogen distributed in rice-growing regions worldwide. Here, we identified a novel transcription factor UvCGBP1 ( C utinase G -box b inding p rotein) from this fungus, which is unique to ascomycetes. Deletion of UvCGBP1 affected development and virulence of U. virens . A total of 865 downstream target genes of UvCGBP1 was identified using ChIP-seq and the most significant KEGG enriched functional pathway was the MAPK signaling pathway. Approximately 36% of target genes contain the AGGGG (G-box) motif in their promoter. Among the targets, deletion of UvCGBP1 affected transcriptional and translational levels of UvPmk1 and UvSlt2 , both of which were important in virulence. ChIP-qPCR, yeast one-hybrid and EMSA confirmed that UvCGBP1 can bind the promoter of UvPmk1 or UvSlt2 . Overexpression of UvPmk1 in the ?UvCGBP1-33 mutant restored partially its virulence and hyphae growth, indicating that UvCGBP1 could function via the MAPK pathway to regulate fungal virulence. Taken together, this study uncovered a novel regulatory mechanism of fungal virulence linking the MAPK pathway mediated by a G-box binding transcription factor, UvCGBP1.