Antifungal activity of myriocin against Fusarium graminearum and its inhibitory effect on deoxynivalenol production in wheat grains

摘要

Fusarium graminearum, a devastating pathogenic fungus of wheat (Triticum aestivum L.), causes fusarium head blight (FHB) and produces mycotoxins such as deoxynivalenol (DON). This study aimed to explore the potency of myriocin to control postharvest infection of F. graminearum in wheat grains. Myriocin showed excellent antifungal activity against F. graminearum, as evidenced through inhibition on spore germination and mycelial growth. The mechanism of action was investigated by analyzing changes of cell membrane permeability and serine palmitoyl transferase (SPT) activity. Results indicated that myriocin inhibited F. graminearum by disrupting permeability of membrane and result in release of cellular contents. Myriocin suppressed the SPT activity and molecular docking also proved the sC interaction of myriocin-SPT. Significant morphological alterations were observed in SEM imaging, including holes on the hyphae, contraction and disruption of mycelia. In addition, myriocin also showed inhibitory effect on toxigenic activity of F. graminearum in wheat grains by reducing more than 99.0% of deoxynivalenol (DON) and its derivative 15-acetyldeoxynivalenol (15-ADON) synthesis. Quantitative real-time PCR analysis indicated that TRI5 gene expression was downregulated by myriocin and results in the reduction of toxicity. Overall, myriocin exerted effective fungicidal activity to control F. graminearum contamination in wheat grains and provided a lead compound to develop more alternatives for pathogen control.