Transcription Factor TrStuA Regulates Vegetative Growth, Virulence, and Trichothecin Synthesis in <i>Trichothecium roseum</i>

<i>Trichothecium roseum</i>, 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 <i>T. roseum</i> is poorly understood. In this study, we characterized functions of the APSES-type transcription factor StuA in <i>T. roseum</i>. Using gene knockout and complementation methods, we generated the Δ<i>TrStuA</i> deletion mutant and its complementary strains. Compared to the wild type and complementary strains, the Δ<i>TrStuA</i> 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 <i>TRI</i> cluster genes responsible for TCN biosynthesis. Notably, HPLC detection showed that TCN was not detectable in the Δ<i>TrStuA</i> mutant, confirming that TrStuA positively regulates TCN biosynthesis. These findings highlight the essential role of TrStuA in <i>T. roseum</i> and provide a novel target for fungicide development to manage toxin contamination and postharvest pink rot.