Selenium-Doped Biomass-Based Nanoparticles Drive Agricultural Emulsions toward a Novel “Offense-Defense Integration” Strategy

Pesticide formulations with enhanced efficiency and environmental sustainability are crucial for modern agriculture. An agricultural Pickering emulsion (Pro-Pickering), stabilized by selenium (Se)-doped zein nanoparticles, developed for delivering the model fungicide prochloraz (Pro) using a multifunctional approach is presented. Its interfacial transfer efficiency is significantly improved, with rain wash resistance enhanced by 27% compared to commercial emulsifiable concentrates (Pro-EC). Pro-Pickering delivers Pro to eliminate fungi while incorporating nano-Se to activate endogenous disease resistance mechanisms, thereby strengthening long-term defense capabilities. Compared to commercial emulsion concentrates with unimodal fungicidal activity, Pro-Pickering is 48.8% more effective against Botrytis cinereal, demonstrating the advantage of “simultaneous attack and defense.” Joint multiomics analyses revealed that nano-Se in Pro-Pickering enhanced cucumber resistance to B. cinerea by activating jasmonic acid (JA)-mediated immunity, upregulating amino acid metabolism for defense compounds, and mitigating oxidative stress via glutathione metabolism. Additionally, it sustained photosynthetic efficiency for energy supply and reinforced JA biosynthesis through α-linolenic acid metabolism, collectively strengthening immune defense. Furthermore, the preliminary toxicity assessments indicate that the formulation has relatively low impact on non-target organisms, making it suitable for eco-friendly and sustainable agricultural practices. This work provides scope for developing plant disease management strategies using eco-friendly, sustainable approaches.