Antifungal activity and inhibition of the molecular mechanism of lavender essential oil against Ustilaginoidea virens

Ustilaginoidea virens is the infectious agent responsible for rice false smut disease, which infects rice in rice-growing regions worldwide. This study aimed to investigate the antifungal effect and the inhibition of molecular mechanism of lavender essential oil (LEO) against U. virens. The antifungal effects of LEO were studied assessed by examining mycelia growth, spore germination, conidial production, mycelia dry weight, and protein content. Scanning electron microscopy showed serious impairment in the mycelial morphology of U. virens when exposed to the EC50 concentration of LEO. In this study, comparative transcriptome methods were used to analyze the gene expression levels of U. virens under LEO stress. The results revealed that 845 genes (371 upregulated, 474 downregulated) and 1173 genes (554 upregulated, 619 downregulated) were differentially expressed in U. virens treated with LEO (CL) compared to the control samples (CK) after 4 and 8 d of treatment, respectively. Further analyses indicated that various genes related to cell wall synthesis, cell membrane synthesis, protein synthesis, and the energy metabolism pathway were significantly downregulated. These results suggest that LEO may reduce the expression of genes related to the cell wall, cell membrane, protein synthesis, and energy metabolism pathways of U. virens, thus destroying the stability and fluidity of cells and interfering with their protein synthesis and energy metabolism to achieve an antifungal effect. •Lavender essential oil (LEO) exhibited potent antifungal activity against U. virens.•LEO can destroy the surface structure of hypha.•LEO can reduce the protein content of the U. virens mycelia.•The molecular mechanism of LEO against U. virens by comparative transcriptome.•LEO showed good application potential as fungicide.