Antifungal efficacy of paeonol on Aspergillus flavus and its mode of action on cell walls and cell membranes

Abstract

Aspergillus flavus (A. flavus) contaminates agricultural products and endangers human health. Plant-derived natural compounds are potential antifungal agents that are superior to chemical fungicides. Paeonol can effectively inhibit A. flavus growth, and its potential antifungal actions were investigated by examining a series of phenotypic changes. The damage to cell walls was visualized by surface ultrastructural characterization and quantified by the decreases in β-1,3-glucan and chitin content. The integrity of the cell membranes was damaged, as indicated by propidium iodide (PI) staining, cell constituent release, relative conductivity, pH values, and the contents of extracellular metal ions (e.g., K+ and Na+). Furthermore, paeonol decreased the content of total lipids, induced lipid peroxidation, altered glycerol content, and destroyed trehalose. Finally, paeonol also reduced the pathogenicity of A. flavus in both peanuts and corn kernels. This study proposes paeonol as a new antifungal agent for use against A. flavus and provides new insights into the mechanism underlying the alterations in A. flavus in response to paeonol.