Utilizing zinc oxide nanoparticles as an environmentally safe biosystem to mitigate mycotoxicity and suppress Fusarium graminearium colonization in wheat

The biosynthesis of zinc oxide nanoparticles (ZnONPs) offers great potential for plant disease management due to their potent antimicrobial properties and environmental safety. However, the precise mechanisms underlying their antifungal mode of action and role in suppressing mycotoxins remain unclear. This study aims to elucidate the mechanisms by which ZnONPs suppress the pathogenic fungus Fusarium graminearium, known to cause Fusarium head blight in wheat. Additionally, it investigates how ZnONPs mitigate the production of mycotoxins, which pose risks to humans and ruminants. The study demonstrates that ZnONPs, bioproduced by Pseudomonas poae (P. poae), inhibit not only fungal growth, colony formation, and spore germination, but also significantly reduce mycotoxin production of F. graminearium by inhibiting the synthesis of deoxynivalenol (DON), downregulating the FgTRI gene, and causing morphological alterations of the toxisomes. The results also highlight that ZnONPs exert significant effects on fungi through multiple mechanisms, including cell wall damage and the generation of reactive oxygen species (ROS). Moreover, ZnONPs effectively inhibit F. graminearium in wheat leaves and coleoptiles. Fluorescence microscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and optical microscopy all show that ZnONPs stop F. graminearium from getting into wheat plants and colonising them. Overall, the findings of this study provide evidence that ZnONPs are highly effective in reducing F. graminearium colonization in wheat plants and effectively decreasing mycotoxin production through multiple pathways.