关键词: 枯草芽孢杆菌, 挥发性物质, 橡胶灵芝菌, 抑菌活性

Abstract: Red root is one of the most devastating diseases of rubber tree caused by Ganoderma pseudoferreum. In order to provide new materials for the prevention and control of red root disease of rubber trees, the inhibitory effect of volatile organic compounds produced by Bacillus subtilis Czk1 on Ganoderma pseudoferreum was investigated. In this study, G. pseudoferreum was used as the target fungus, and the antifungal activity of 12 kinds of pure volatile organic compounds  produced by Czk1 was detected by pair culturing method. Virulence of the active volatile organic compounds was determined by the growth rate method. The effect of volatile organic compounds on morphology and cell membrane permeability of G. Pseudoferreum cells were detected. The results showed that the 12 volatile organic compounds had different degrees of antifungal activity against G. pseudoferreum, and their inhibition rate ranged from 15.2% to 100%. Among them, benzaldehyde had the strongest antifungal activity against pathogens, and the rate reached 100%. In the determination of the virulence of 9 pure compounds to pathogens, the EC₅₀ of benzaldehyde, 3,5-dimethoxyacetophenone, and butylated hydroxytoluene were  20.30, 30.62, 40.96 μg·mL^-1, respectively. The concentration of the three mixed components was 25 μg·mL^-1, the inhibitory rate against G. pseudoferreum was 670%. The mycelia of pathogen were greatly twined, the cell wall became thinner, part of the membrane structure was incomplete and the permeability of pathogen cell was affected after  treated with volatile organic compounds. The good fungistatic activity of volatile organic compounds produced by Czk1 was the result of the synergy of these volatile organic compounds. These volatile organic compounds had great application prospects and could be used as chemical pesticide substitutes to prevent and cure rubber tree root disease.

Key words: Bacillus subtilis, volatile organic compounds, Ganoderma pseudoferreum, antifungal activity