Antifungal Activity of Trans-2-Hexenal AgainstPenicillium cyclopiumby a Membrane Damage Mechanism

The study investigated the antifungal activity and potential antifungal mechanisms of volatile compounds (i.e., E-2-hexenal) against Penicillium cyclopium, one of the main tomato postharvest pathogens, which was obtained and purified from postharvest tomato surface. Experimental data suggested that the volatile compound exhibited strong antifungal activity against the targeted pathogens, with minimum inhibitory concentration and minimum fungicidal concentration of 160 μL/L and 320μL/L for E-2-hexenal, respectively. The membrane permeability of the P. cyclopium increased with increasing concentrations of E-2-hexenal, as evidenced by cell constituent release, leakage of potassium ions, and extracellular conductivity. Moreover, E-2-hexenal could induce a decrease in total lipid content and extracellular pH. These results suggest that the anti-fungal activity of E-2-hexenal against P. cyclopium can be attributed to the disruption of the cell membrane integrity, the increase of membrane permeability and the leakage of cell components. Practical Applications Penicillium cyclopium was isolated from the surface of tomato fruits after harvest. E-2-hexenal had an inhibitory effect on the hyphae and spores of P. cyclopium. The minimum inhibitory concentration and minimum fungicidal concentration were determined by using different concentrations of E-2-hexenal against P. cyclopium. The study results indicate that the antifungal activity of E-2-hexenal against P. cyclopium can be attributed to the disruption of the cell membrane integrity, the increase of membrane permeability and the leakage of cell components. The study results provided a reference for extending the storage of tomato fruits.