Control of wheat Fusarium head blight by biosynthesized selenium nanoparticles

Fusarium graminearum (F. graminearum)- induced wheat Fusarium head blight (FHB) substantially reduced wheat yield and grain quality, and has evolved into a serious threat on a global scale. Although chemical pesticides served as the mainstay for FHB prevention for decades, prolonged use has led to pathogen resistance and environmental risks, which in turn constrain sustainable development. Biogenic nanomaterials have attracted global attention for their potential to substitute for partial pesticides due to their environmentally friendly and highly effective properties, such as biogenic selenium nanoparticles (Bio-SeNPs). However, the understanding of the underlying mechanisms of Bio-SeNPs in preventing and controlling FHB is still rudimentary. To address it, this study carried out both in vivo and in vitro experiments, as well as field trials to verify the function of Bio-SeNPs. Therefore, Bio-SeNPs were synthesized by Bacillus subtilis 168. In vitro assays demonstrated that 0.4 mmol L⁻¹ was the optimal concentration of Bio-SeNPs for inhibiting F. graminearum growth, achieving an inhibition efficiency of over 70%. In vivo experiment showed that Bio-SeNPs (0.4 mmol L⁻¹) not only significantly alleviated F. graminearum -caused browning in wheat seedlings and spikes, but also promoted proline accumulation, enhanced antioxidant enzyme activities, while reducing reactive oxygen species accumulation. In field trials, Bio-SeNPs application decreased FHB disease index by more than 80%, further demonstrating their role in plant protection. Summarily, the application of Bio-SeNPs can restrain the occurrence of FHB by directly inhibiting the pathogens' growth, indirectly enhancing systemic resistance of wheat, thus delivering nove l insights and viable strategies for sustainable management of FHB.