Transcription Factor TrStuA Regulates Vegetative Growth, Virulence, and Trichothecin Synthesis in Trichothecium roseum

Trichothecium roseum, a postharvest apple pathogen, produces the mycotoxin trichothecin (TCN), which poses a significant threat to human health. However, the regulatory function on TCN synthesis in T. roseum is poorly understood. In this study, we characterized functions of the APSES-type transcription factor StuA in T. roseum. Using gene knockout and complementation methods, we generated the ΔTrStuA deletion mutant and its complementary strains. Compared to the wild type and complementary strains, the ΔTrStuA deletion mutant exhibited reduced vegetative growth, conidiation, stress tolerance, and pathogenicity. Transcriptomic analysis and qRT-PCR assays revealed that TrStuA significantly affects secondary metabolic genes, especially the TRI cluster genes responsible for TCN biosynthesis. Notably, HPLC detection showed that TCN was not detectable in the ΔTrStuA mutant, confirming that TrStuA positively regulates TCN biosynthesis. These findings highlight the essential role of TrStuA in T. roseum and provide a novel target for fungicide development to manage toxin contamination and postharvest pink rot.