Abstract: To further study the fungicidal effect and mechanism of canthin-6-one alkaloid from Ailanthus altissima on Fusarium graminearum, the inhibitory activity was determined by microdilution and mycelial growth inhibition methods. The antifungal mechanism of canthin-6-one was analyzed from the point of view of cell membrane by detecting the extracellular relative conductivity, content release, malondialdehyde content, hydrogen peroxide content and protective enzyme activity. The results showed that canthin-6-one had a significant inhibitory effect on Fusarium graminearum, with a minimum inhibitory concentration of 8.0 μg/mL and a half-effective concentration of 1.85 μg/mL. The extracellular relative conductivity and the content release amount of the treated mycelia were significantly increased, while malondialdehyde and hydrogen peroxide contents were also significantly elevated. It was indicated that canthin-6-one induced oxidative damage to the cell membrane of Fusarium graminearum, resulting in the loss of membrane integrity and increased permeability, thus inhibiting mycelial growth.

Key words: Ailanthus altissima, Fusarium graminearum, alkaloid, antifungal effect, cell membrane