Abstract

Trichothecium roseum ( T. roseum ) is a significant postharvest pathogen that infects a wide range of fruits and vegetables. This study investigated the antifungal activity of cuminal (CA), the major active component of cumin essential oil, against T. roseum . The results showed that CA notably inhibited spore germination, germ tube elongation, mycelial growth, and pathogenicity in T. roseum . Mechanistic analyses revealed that CA induced excessive intracellular reactive oxygen species (ROS) accumulation in T. roseum , despite antioxidant elicitation, leading to oxidative stress. This stress triggered mitochondrial dysfunction, characterized by ultrastructural damage, membrane depolarization, cytochrome c release, and disturbance of Ca 2+ homeostasis. Further examination showed that CA altered mitochondrial dynamics and activated TrAtg8-mediated mitophagy, as evidenced by upregulated autophagy-related genes and the definite colocalization of GFP-TrAtg8 with mitochondria and vacuoles. Excessive mitophagy impaired mitochondrial function, resulting in a 44.14% decrease in energy charge in CA-treated spores compared to the untreated control. This energy deficit led to the suppression of gene expression of cell wall-degrading enzymes, required for pathogenic attack, and to impaired environmental alkalization capability, which is crucial for successful host colonization. Consequently, this led to a significant reduction in T. roseum 's pathogenicity. Taken together, this study establishes that CA disrupts T. roseum 's energy metabolism via a cascade initiated by oxidative stress, which dysregulates mitochondria and traps the cell in a futile cycle of excessive mitophagy, ultimately decreasing its pathogenic capacity. This multi-target mechanism highlights CA's potential as a natural postharvest preservative for fruits and vegetables against T. roseum .