Molecular Mechanism: Inhibition of Fusarium oxysporum T-2 Toxin Synthesis by Surfactin in Dried Fish: Induction of Yap1 Nucleation by ROS Accumulation

(1) T-2 toxin synthesized by <i>Fusarium oxysporum</i> (<i>F. oxysporum</i>) can cause deterioration of dried fish and endanger human health. (2) The molecular mechanism by which antibacterial lipopeptides surfactin inhibited <i>F. oxysporum</i> growth and toxin production was elucidated by investigating the intracellular ROS production pathway and the subcellular distribution and transcriptional activity of the transcription factor <i>Yap1</i> and its regulation of <i>Tri5</i> gene in <i>F. oxysporum</i>. (3) Surfactin caused hyphal damage and nucleic acid and protein leakage; thus, the growth of <i>F. oxysporum</i> was disrupted. Surfactin's excessive accumulation of intracellular ROS triggered the translocation of transcription factor <i>Yap1</i> into the nucleus, resulting in toxin cluster gene <i>Tri5</i> expression inhibition, thereby blocking T-2 toxin synthesis. (4) This is a novel mechanism by which surfactin inhibits the growth and T-2 toxin synthesis of <i>F. oxysporum</i> from multiple aspects, including cell structural integrity and the ROS-<i>Yap1</i> signaling pathway. (5) This study provides a theoretical basis for the application of surfactin in the antifungal control of aquatic dry products.