Influence of α-terpineol on the growth and morphogenesis of Penicillium digitatum

Background: Plant essential oils could act effectively against postharvest diseases, alpha-terpineol, a typical terpenoid of plant essential oils, exhibited strong antifungal activity in against Penicillium italicum, but the possible action mechanism remains undetermined. In present study, alpha-terpineol was evaluated for antibacterial activity against Penicillium digitatum along with the mode of their antibacterial action. Results: The results showed that mycelial growth of P. digitatum was strongly inhibited by alpha-terpineol, with the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of 2.00 and 8.00 mu l/ml, respectively. Scanning electron microscopy observation revealed that alpha-terpineol obviously altered the morphology of P. digitatum hyphae by causing the loss of cytoplasm and distortion of mycelia. A rapid increase in the membrane permeability of P. digitatum was observed after treated with MIC or MFC of alpha-terpineol, evidenced by the release of cell constituents, the extracellular conductivity, and the extracellular pH. In addition, alpha-terpineol apparently induced a decrease in total lipid contents of P. digitatum cells, indicating the destruction of cell membrane structures after treatment. Conclusions: Based on our study, alpha-terpineol might affect the cell wall synthesis and lead to the disruption of cell wall. The cell wall disruption affected fungal morphogenesis, the integrity of membrane and leakage of intracellular components, these results suggested that alpha-terpineol treatment inhibited the growth of P. digitatum.