Silica-Activated Redox Signaling Confers Rice with Enhanced Drought Resilience and Grain Yield

Under a changing climate, enhancing the drought resilience of crops is critical to maintaining agricultural production and reducing food insecurity. Here, we demonstrate that seed priming with amorphous silica (SiO₂) nanoparticles (NPs) (20 mg/L) accelerated seed germination speed, increased seedlings vigor, and promoted seedling growth of rice under polyethylene glycol (PEG)-mimicking drought conditions. An orthogonal approach was used to uncover the mechanisms of accelerated seed germination and enhanced drought tolerance, including electron paramagnetic resonance, Fourier transform infrared spectroscopy (FTIR), metabolomics, and transcriptomics. It was revealed that the unique surface chemistry of amorphous silica, characterized by an enrichment of silanol and siloxane groups, can catalyze the production of reactive oxygen species. This, in turn, initiates redox signaling and activates downstream drought-responsive genes. In addition, silica-primed seeds exhibited a significant enrichment of 18 amino acids and 6 sugars compared to those undergoing hydropriming, suggesting the accelerated mobilization of stored energy reserves. The drought-tolerance trait was observed in vegetative tissues of 35 day-old plants, where this tolerance was associated with an accelerated catabolism of amino acids and an enhanced anabolism of antioxidants. A separated field trial showed that SiO₂NPs seed priming not only increased rice grain yield by 7.77% (p = 0.051) and 6.48% (p = 0.066), respectively, under normal and drought conditions but also increased the grain amino acid content. These results demonstrate that a simple and cost-effective nanoseed-priming approach can convey life cycle-long drought tolerance while simultaneously increasing rice grain yield and nutrition quality, providing an effective and sustainable strategy to cultivate climate-resilient crops.