Unleashing antifungal power: Nanopriming with selenium boosts JA signaling, suppresses pathogen enzymes, and activates phytoalexins for enhanced Fusarium graminearum resistance in maize

INTRODUCTION: Stalk rot caused by Fusarium graminearum (F. graminearum) poses a serious threat to maize production, further exacerbated by contamination with the mycotoxin deoxyninylenol (DON). Although selenium nanoparticle (SeNP) priming technology shows potential for enhancing crop resistance, the systematic regulatory mechanisms by which it reprograms plant defense responses against this pathogen remain unclear. OBJECTIVES: This study aimed to elucidate the molecular mechanisms through which SeNP priming regulates transcriptional and metabolic reprogramming in maize seedlings to resist F. graminearum. METHODS: This study integrated widely-targeted metabolomics, transcriptomics, and physiological assays to analyze samples collected three days after F. graminearum infection. We systematically compared physiological and biochemical differences, including DON content, expression of key genes, antioxidant levels, and disease-related resistance components, between the water-treated control group and the group treated with 50 mg/L SeNP. RESULTS: Our results demonstrate that SeNP priming strengthens the maize antioxidant system by modulating the activity of the glutathione peroxidase (GPX) and activating the AsA-GSH detoxification pathway, thereby reducing the toxicity of DON. Furthermore, SeNP activates the α-linolenic acid-JA signaling cascade, establishing a chemical defense that enhances phenolic and benzoxazinoid phytoalexin biosynthesis. Within this dual defense framework, virulence gene (TRI1 and TRI5) expression was downregulated (by 35.1% and 19.9%, respectively), leading to a 42.2% reduction in DON levels and significantly inhibited β-glucosidase activity. CONCLUSION: SeNP priming enhances maize resistance to F. graminearum by boosting JA signaling, activating the antioxidant and detoxification system, and inducing the synthesis of phenolic and benzoxazinoid phytoalexins. This study demonstrates that SeNP priming is a practical and sustainable crop protection strategy. Future research should focus on field validation across diverse genotypes and environments, economic feasibility analysis, and exploring its synergistic potential with other biocontrol agents or agronomic practices to further improve crop resilience and reduce reliance on conventional fungicides.