Farnesol produced by the biocontrol agent Candida ernobii can be used in controlling the postharvest pathogen Penicillium expansum

This study was conducted to investigate the effect of Candida ernobii strain Pg2-5 against postharvest disease of Penicillium expansum and to evaluate the possible mechanisms involved. Disc diffusion assay showed that Pg2-5 exhibited an inhibitory effect against P. expansum growth. An antifungal compound was isolated from the cell-free supernatant culture of Pg2-5 and identified as farnesol. The minimal inhibitory concentration (MIC) and minimum fungicidal concentrations (MFC) of farnesol for P. expansum were 15 and 100 μM, respectively. The addition of farnesol promoted reactive oxygen species (ROS) burst, and increased ultrastructure disintegration of mitochondria. These results indicate that antifungal compound production is one of the modes of action of C. ernobii Pg2-5 against postharvest pathogen of P. expansum. ROS may be an inducer, and mitochondria are potential target of the cytotoxicity process of farnesol.   Key words: Postharvest, Candida ernobii, biocontrol, farnesol.