Inhibitory Mechanisms of Plant Volatile 1-Octanol on the Germination of Aspergillus Flavus Spores

Abstract

Biogenic volatile organic compounds have promising applications in controlling fungal spoilage of postharvest agro-products and perishable foods. In a previous study, we discovered that the plant volatile 1-octanol showed considerable potential for controlling Aspergillus flavus growth. In this study, the inhibitory effects of 1-octanol on the germination of A. flavus spores were investigated. A. flavus spores did not germinate when exposed to 1.5 µL/mL 1-octanol, and 3.5 µL/mL 1-octanol caused spore death. Biochemical analysis showed that 1-octanol caused a decrease in ergosterol and ATP content, and an increase in hydrogen peroxide and superoxide anion content in a dose-dependent manner. Transcriptomic analysis demonstrated that there were 4117 differentially-expressed genes in A. flavus spores exposed to 1.5 µL/mL 1-octanol, mainly enriched in metabolic pathways, steroid biosynthesis, secondary metabolite biosynthesis, ribosomes, glutathione metabolism, the mitogen-activated protein kinases signaling pathway, and pyruvate metabolism. Flow cytometry results showed that 1-octanol treatment resulted in hyperpolarization of the mitochondrial membrane potential, accumulation of reactive oxygen species, and apoptosis. TdT-mediated dUTP nick end labeling/4′,6-diamidino-2-phenylindole double staining and monodansylcadaverine staining results indicated that 1-octanol treatment resulted in DNA fragmentation and induced autophagy, respectively. These results provide new insights into the inhibitory mechanism of 1-octanol on A. flavus spore gemination and would facilitate the application of 1-octanol for the protection of postharvest agricultural products.