Sesamol inhibits fungal growth by destroying the redox dynamic equilibrium in Pestalotiopsis neglecta

Disruption of the cellular antioxidant system is an effective way to control fungal pathogens. Many phenolic compounds have been shown to inhibit microbial growth by disrupting the cellular redox balance or antioxidant system. Sesamol (Ses), an aromatic phenol isolated from sesame oil, has good inhibition effects in several bacteria and fungi, but its inhibition activity against plant pathogenic fungi remains underexplored. In this study, Ses caused damage to the fungal mycelial structure. Additionally, Ses markedly suppressed the activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in P. neglecta. At a concentration of 300 μg/mL, the malondialdehyde (MDA) content was 1.8-fold higher than that of the control group. Transcriptomics analysis revealed that Ses downregulated the expression of genes involved in redox homeostasis while upregulating genes associated with membrane lipid peroxidation. In conclusion, Ses disrupted the redox balance of P. neglecta, promoted membrane lipid peroxidation, compromised the integrity of the cell membrane, and ultimately led to fungal cell death. These findings provide novel insights into the antifungal mechanism of Ses and highlight its potential as a plant-derived pesticide.