Antifungal Action of α-Terpineol on Imazalil-Resistant Penicillium digitatum Pdw03

This study explored the inhibitory effect and potential antifungal mechanism of α-terpineol against an imazalil-resistant strain of Penicillium digitatum Pdw03. In vitro experiment showed that α-terpineol exhibited antifungal activity against P. digitatum Pdw03, with minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of 4.00 μL/mL. In vivo results showed that α-terpineol at MFC and 5 MFC significantly reduced the incidence of green mold and lesion diameter in ponkan fruit inoculated with P. digitatum Pdw03. Propidium iodide (PI) staining indicated that 1/2 MIC α-terpineol evidently decreased the cell membrane integrity, ergosterol content (P < 0.05) and gene expression of squalene synthase (ERG9) (P < 0.05) in P. digitatum Pdw03. These results suggest that α-terpineol affects the growth of P. digitatum Pdw03 by inhibiting the gene expression of ERG9, and thus is an effective alternative for controlling postharvest citrus diseases.