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

Abstract 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.