Abstract:[Objective] Soft rot of postharvest peach fruit, induced by Rhizopus stolonifer, causes huge economic loss. Synthetic fungicides, which are effective for controlling postharvest diseases of peach fruit, pose a threat to food safety, trigger resistance development in the pathogen, and pollute the environment in the instance of long-term use. In this study, we explored the potential inhibitory effect of the biogenic fungicide 1-octen-3-ol on soft rot of peach fruit, hoping to provide an environmentally friendly fungicide for this disease and a reference for the control of soft rot in postharvest peach fruit. [Methods] The peach fruit was fumigated with 1-octen-3-ol after the inoculation with R.stolonifer, and the expression of disease resistance-related genes and activities of related enzymes were determined. The effect of 1-octen-3-ol on the hyphae and spores of R.stolonifer was investigated in vitro. [Results] Fumigation with 1-octen-3-ol at 55.80 μg/mL reduced (P<0.05) the incidence of the disease and lesion diameter and improved the expression of nonexpressor of pathogenesis-related 1 (NPR1), pathogenesis-related protein 1 (PR1), chitinase (CHI), and β-1,3-glucanase (GLU) genes, and the activities of CHI and GLU. The in vitro experiment showed that 1-octen-3-ol could inhibit the growth of R.stolonifer hyphae on the plate and destroy the cell structure of mycelium. Moreover, 1-octen-3-ol could reduce the content of ergosterol in mycelium (P<0.05) and effectively suppress the germination of R.stolonifera sporangiospores and the elongation of germ tubes. It caused reactive oxygen species (ROS) burst and mitochondrial damage by destroying the membrane structure of spores, resulting in apoptosis. [Conclusion] 1-octen-3-ol can not only directly destroy the hyphae and spores of R.stolonifer, but also induce systematic acquired resistance (SAR) of peach fruit to inhibit the spread of postharvest soft rot.
