Molecular mechanism of anisaldehyde targeting the cell membrane of Ustilaginoidea virens based on integrated transcriptome and metabolome analyses

Rice false smut, caused by the fungal pathogen Ustilaginoidea virens , poses a significant threat to rice production worldwide. This study aimed to identify the specific target proteins and binding sites of anisaldehyde in U. virens and to elucidate the molecular mechanisms underlying its antifungal activity. In this study, a combination of electron microscopy techniques, integrated transcriptomic and metabolomic analyses, and molecular docking simulations was employed to investigate the effects of anisaldehyde on U. virens . Anisaldehyde significantly inhibited the mycelial growth of U. virens , with a median effective inhibitory concentration (EC₅₀) of 11.18 μg/mL. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations revealed that anisaldehyde treatment led to morphological abnormalities in the mycelia of U. virens , including wrinkles, twisting, and a rough surface, along with an increased number of lipid droplets and enhanced cell membrane permeability. Integrated transcriptomic and metabolomic analyses demonstrated that anisaldehyde significantly affected the glycerophospholipid metabolism pathway. Molecular docking results indicated that anisaldehyde could stably bind to the UV8b_03588 protein. Molecular dynamics simulations further confirmed that anisaldehyde bound to the UV8b_03588 protein with high affinity, and the protein conformation remained stable after binding without any significant conformational changes. The UV8b_03588 protein of U. virens , as a potential target, and the inhibition of its function may be key mechanism underlying the antifungal activity of anisaldehyde. This study provides a theoretical basis for the development of novel plant-derived antifungal agents and offers new insights into the control of rice false smut.