Trans-2-hexenal reduces postharvest mango stem-end rot by oxidative damage to Neofusicoccum parvum cell membranes

Neofusicoccum parvum is one of the most hazardous pathogens causing mango fruit decay. The present study utilized trans-2-hexenal (TH), a typical antifungal component of plant essential oils (EOs), to control N. parvum both in vivo and in vitro, and attempted to explore the mechanisms involved. The findings showed that at concentrations greater than 0.4 µL/mL, TH exhibited exceptional antifungal activity against N. parvum in vitro. TH application led to the disruption of the structural integrity of both cell walls and cell membranes, with a particular impact on the latter, as evidenced by the dramatically increased propidium iodide level, as well as reduced total lipids and ergosterol content. Further DCFH-DA staining experiments showed that TH induced mycelial reactive oxygen species (ROS) accumulation, which exacerbated cell membrane lipid peroxidation. For easier application of TH, we fabricated aerogel-loaded TH (ALTH) materials, which demonstrated excellent antifungal activity in vitro. Infestation studies on fruits demonstrated that ALTH mitigated mango stem-end rot in a dose-dependent fashion, with a concentration of 40 µL/L showing efficacy comparable to the conventional fungicide prochloraz, while maintaining fruit quality. In light of these results, TH works by inducing ROS buildup and oxidative damage to the cell membrane of N. parvum, and is a particularly promising preservative for preventing postharvest infections in mangoes.