Efficacy and Potential Mechanism of Essential Oils of Three Labiatae Plants against the Pathogenic Fungi of Root Rot Disease in Atractylodes chinensis

Atractylodes chinensishas a high medicinal value and is widely cultivated. However, root rot disease seriously affects the yield and quality ofA. chinensis. To develop green and safe pesticides, the inhibitory effect of essential oils (EOs) of three Labiatae plants on the pathogenic fungi that causes root rot disease inAtractylodes chinensiswas investigated. The results showed that theOriganum vulgareEO andThymus mongolicusEO exhibited strong inhibitory effects onFusarium oxysporum,Fusarium solani, andFusarium redolens, with 100% inhibition rate. The low MIC values of EOs and their main components against the three pathogenic fungi indicated that all of them showed strong fungicidal effects. The MIC values ofO. vulgareEO againstF. oxysporum,F. solani,andF. redolenswere 2.60 mg/mL, 3.13 mg/mL, and 1.56 mg/mL, respectively. Analyses using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) showed that theO. vulgareEO severely damaged the cell wall and cell membrane of mycelial cells. TheO. vulgareEO increased cell permeability, leading to a large leakage of cell contents (DNA and proteins). In addition,O. vulgareEO inhibitedF. oxysporumby inducing ROS production and reducing the amount of intracellular GSH, leading to a large accumulation of ROS. This study showed that plant EOs have excellent fungicidal activity and can be used as novel natural and environmentally friendly pesticides for the control of root rot inA. chinensis.Keywords:Atractylodes chinensis;root rot;essential oils;Origanum vulgare;antifungal activity;mechanisms of action