GABA-mediated and light-assisted synthesis of green GABA-SeNPs for microbial control and plant nano-primer

Wheat is a staple crop critical to global food security, yet the synergistic pressures of abiotic stress and seed-borne fungal diseases increasingly threaten its production. To address this dual challenge, we report a scalable, environmentally benign photoreduction method for the synthesis of γ-aminobutyric acid (GABA)-functionalized selenium nanoparticles (GABA-SeNPs). By leveraging GABA, a key metabolic signaling and stress-mitigation agent, as a bifunctional reducing and capping agent, we engineered spherical, polycrystalline nanoparticles with tunable diameters at distinct precursor concentrations. Our results demonstrate that the physicochemical properties of these nanostructures significantly impact their biological performance. As a nanofungicide, it exhibits broad-spectrum activity against Corynespora cassiicola, Colletotrichum truncatum , and Fusarium oxysporum , surpassing the commercial itraconazole in inhibiting hyphal growth. Beyond pathogen control, as a wheat seed primer, GABA-SeNPs modulate seedling growth via a hormetic pathway triggered by regulated oxidative signaling. All priming treatments, varying GABA load in nanoparticles (80 mg or 100 mg) and nanoparticle concentration (10 % or 50 %), significantly improved vigor compared with water-treated seeds ( p <0.0001). GABA-SeNPs prepared with 100 mg of GABA at 10% concentration showed optimal sustained vigor, yielding a 7.0-fold increase. This enhancement was associated with a primed redox state, characterized by elevated levels of hydrogen peroxide and glutathione, and increased total superoxide dismutase activity. Raman spectroscopy analysis confirmed that GABA-SeNPs alter the molecular composition of wheat seeds, with concentration-dependent effects on selenium incorporation, GABA concentration, and associated metabolic changes. This study establishes GABA-SeNPs as a novel, dual-function agro-nanotechnology that simultaneously protects crops from fungal pathogens and primes seeds for enhanced vigor and stress resilience, offering a transformative tool for sustainable agriculture.