Dimethyl trisulfide inhibits Alternaria alternata by disrupting reactive oxygen species (ROS) homeostasis and energy metabolism

Dimethyl trisulfide (DMTS) exhibits potent antifungal activity against Alternaria alternata , yet its molecular mode of action has not been fully elucidated. In this study, we analyzed the key gene expression and phenotypic alterations in A. alternata after DMTS treatment to clarify its potential antifungal mechanism, and to provide insight into possible fungicidal targets. Given the pronounced antifungal activity of DMTS, transcriptomic analysis was performed to profile global gene expression changes in A. alternate following DMTS exposure, complemented by bioinformatics analysis and real-time fluorescent quantitative PCR (RT-qPCR) validation. A total of 2,321 differentially expressed genes (DEGs) were identified, including 934 up-regulated and 1,387 down-regulated genes. RT-qPCR validation confirmed that the gene expression trends were consistent with the transcriptomic data, supporting the reliability of the sequencing results. GO functional annotation and KEGG enrichment analysis revealed that the DEGs were associated with peroxisome formation, fatty acid β -oxidation, cellular ROS homeostasis, and energy metabolism pathways such as the tricarboxylic acid (TCA) cycle. In line with these transcriptional changes, DMTS exposure caused substantial intracellular ROS accumulation, impaired mitochondrial activity, reduced ATP production and DNA fragmentation, reflecting significant bioenergetic impairment and redox imbalance. Collectively, these findings suggest that DMTS inhibits fungal growth by disrupting peroxisome formation, mitochondrial function, and triggering excessive ROS-mediated oxidative damage. Simultaneously, DMTS impedes fatty acid β -oxidation and the TCA cycle, resulting in significant cellular ATP depletion. These combined effects ultimately inhibited the growth of A. alternata .