Efficient Control of <i>Fusarium</i> Head Blight and Reduction of Deoxynivalenol Accumulation by a Novel Nanopartner-Based Strategy

Chemical control of <i>Fusarium</i> head blight (FHB) in wheat plants is often challenged by the resistance outbreak and deoxynivalenol (DON) accumulation. Developing green partners for fungicides is crucial for reducing fungal growth, mycotoxin contamination, and agricultural fungicides input. Herein, we investigated the mechanism of MgO nanoparticles (NPs) in controlling FHB. The EC₅₀ of MgO NPs on mycelial growth was 105.2 μg/mL. At this concentration, they inhibited the spore germination, DON production, and wheat colonization of <i>Fusarium graminearum</i> by 56.0%, 24.5%, and 43.8%, respectively, exhibiting superior performance compared to nine other bioactive NPs such as ZnO and TiO₂. Importantly, MgO NPs showed an additive effect with carbendazim and azoxystrobin in inhibiting <i>F. graminearum</i>. The extracellular toxicity of MgO NPs against <i>F. graminearum</i> was mainly attributed to the inhibition of fungal growth and germination by oxidative damage, alkaline damage, and cell structure damage. Although MgO NPs could not be absorbed into mycelia, they (EC₉₀) decreased the soluble protein content and DNA concentration of mycelia by 27.8% and 42.3%, respectively, and increased the pyruvate content by 67.4%, demonstrating that the intracellular toxicity was mainly based on their inhibition of protein and DNA production and promotion of carbohydrate degradation. With low risks to nontarget organisms, MgO NPs could be a promising nanopartner for fungicides to protect wheat from FHB and mitigate fungicide overuse.