Heptanal inhibits the growth of Aspergillus flavus through disturbance of plasma membrane integrity, mitochondrial function and antioxidant enzyme activity

Abstract

Fungal contamination poses a threat to agriculture, food production and human health, and a safe and effective method to limit fungal contamination is still needed. In this study, the inhibitory potency of heptanal, a natural volatile chemical, against Aspergillus flavus growth was evaluated, and its mechanism of action was explored. The minimum inhibitory concentrations (MICs) of heptanal vapor fumigation and liquid contact culture were 0.085 and 0.8 μL/mL, respectively. A total of 79 significant differentially abundant metabolites, including 37 upregulated and 42 downregulated ones, were identified in A. flavus mycelia after exposure to 0.8 μL/mL heptanal for 6 h. Metabolomics analysis revealed that heptanal had destructive effects on plasma integrity and mitochondrial function in mycelia. Biochemical analysis confirmed that heptanal caused intracellular substance leakage and resulted in reduced intracellular ATP content, reactive oxygen species (ROS) accumulation, and lower mitochondrial dehydrogenase and ATPase activities. Evaluation of the control efficacy of heptanal fumigation on wheat grain under simulated storage conditions revealed that 225.0 μL/L heptanal vapor could inhibit A. flavus growth under 19% moisture. These results provide insights into the antifungal mechanism of heptanal against A. flavus growth as a promising bio-preservative.