Nanoenabled Priming Helps Wheat to Handle Heat and Disease.

Abstract

Global wheat production faces growing threats from rising temperature and pathogen attacks under climate change. Here, we developed a nanoenabled seed priming strategy that simultaneously enhanced wheat thermotolerance and resistance to Fusarium head blight (FHB). Specifically, under heat shock stress (45 °C, 24 h), wheat seedlings that underwent AgSiO₂NP (40 mg/L AgNPs + 40 mg/L SiO₂NPs) seed priming exhibited reduced wilting symptoms, increased biomass (22.8%), improved water uptake, maintained cellular membrane integrity, and delayed protein/starch catabolism compared to the hydroprimed control. Reactive oxygen species (ROS) localization assays and RNA-seq analysis reveal that AgSiO₂NP priming triggered ROS-mediated activation of "plant hormone signal transduction" and the "MAPK signaling pathway" in seeds. These molecular changes persisted into the seedling stage, establishing a primed state that enhanced seedlings' heat resilience. AgSiO₂NP-primed seedlings also showed enhanced resistance to <i>Fusarium graminearum</i>, even under hotter conditions (28 °C). Comparative transcriptomics of wheat seedlings pre- and postpathogen infection revealed that AgSiO₂NP priming intensified defense-related pathways, including the MAPK signaling pathway, plant hormone signal transduction pathway, plant-pathogen interaction pathway, and specialized metabolite biosynthesis pathways, as compared to hydropriming, leading to robust immune activation and disease resistance during pathogen attack. We also demonstrate that an inexpensive ($0.5-2 per acre) and environmentally friendly alternative, CuO@SiO₂ nanoparticles, efficiently enhances the resistance of wheat seedlings to FHB. This study proposes a nontransgenic approach for engineering climate-resilient wheat, providing a sustainable strategy to address food insecurity exacerbated by climate change.