Antifungal efficacy of sixty essential oils and mechanism of oregano essential oil against Rhizoctonia solani

Essential oils are natural compounds that have been widely studied in the control of various microbial diseases. In this paper, 60 essential oils were selected to evaluate the antifungal activity against six plant pathogenic fungi. The result indicates that oregano essential oil is an effective natural antifungal product and has been found to be effective in inhibiting Rhizoctonia solani (EC50 =22.89 & mu;g/mL). Morphological studies showed that oregano essential oil seriously damaged the mycelial morphology, and ultrastructural observations showed that it has effect on the cell membrane. The gene expressed level of Rhizoctonia solani was further studied by tran-scriptomics. It was found that oregano essential oil affected the activity of oxidoreductase, promoted the accu-mulation of reactive oxygen species and the production of malondialdehyde, which caused lipid peroxidation, led to the destruction of cell membrane permeability and integrity and finally caused the cell death. Besides, oregano essential oil also inhibited the formation of sclerotia of Rhizoctonia solani. The present study suggests that the essential oil can be regarded as a new and potential source of natural and eco-friendly antifungal agents.

Automated summary

This study selected 60 essential oils to evaluate their antifungal activity against six plant pathogenic fungi. The results showed that oregano essential oil is an effective natural antifungal product and can inhibit Rhizoctonia solani. Morphological and ultrastructural observations revealed that oregano essential oil damaged the mycelial morphology and cell membrane. Further transcriptomic analysis found that oregano essential oil affected the activity of oxidoreductase, leading to lipid peroxidation and cell death. Additionally, oregano essential oil inhibited the formation of sclerotia of Rhizoctonia solani. This study suggests that essential oils can serve as a new and potential source of natural and eco-friendly antifungal agents.