Bioactivity and Mechanisms of Botanical Fungicide Magnolol against Trichoderma hamatum as a Novel Pathogen of Sweet Potato.

Abstract

Sweet potato is a vital crop worldwide, but its storage roots are susceptible to infection by numerous fungal pathogens, leading to substantial postharvest losses. In this study, a highly pathogenic fungal strain was isolated from infected sweet potato storage roots. Through morphological and molecular characterization, the strain was identified as Trichoderma hamatum, representing the first report of this species as a sweet potato pathogen. The botanical compound magnolol exhibited a strong antifungal activity against T. hamatum, demonstrating an excellent protective efficacy against the pathogen-induced disease. Electron microscopy analyses indicated that magnolol could effectively disrupt ultrastructure of T. hamatum. Transcriptomic analyses revealed multiple biological pathways modulated by magnolol. In particular, magnolol could damage the cell membrane integrity of T. hamatum and disturb its energy metabolism. These findings provide critical insights for managing postharvest diseases of sweet potato and highlight the potential of magnolol as a natural antifungal agent for food preservation.