CuO@SiO₂ Seed Priming Enhances Drought Tolerance and Phosphorus Acquisition Efficiency of Maize

Sustainable agriculture requires minimizing resource inputs while maximizing the outputs. Here, we report that rationally engineered Fenton-like CuO@SiO₂ nanoparticles (NPs), as a seed priming agent (20 mg/L, 24 h), concurrently enhanced drought tolerance and phosphorus (P) acquisition efficiency of maize, a climate vulnerable staple crop. Importantly, life cycle field pot trials reveal that CuO@SiO₂ NPs seed priming increased the grain yield by 9.3% and 16.6%, respectively, under normal and drought conditions, compared to the hydropriming control. This enhanced drought-resilience and yield were attributed to reactive oxygen species (ROS)-intensified root system architecture (RSA) plasticity, including enhanced root hair density, deeper primary root, and prolific lateral root branching. RNA-seq revealed the activation of genes related to RSA modulation (PLA2, PG, and EXP), P/N/S uptake and assimilation (PHT, NRT, NR, NiR, and SULTR), and drought tolerance (ELIP, LEA, and DRP) in CuO@SiO₂ NPs-primed seeds. Additionally, seed priming altered the seed metabolite profile, systematically elevating the content of adenosine triphosphate (24.1%), amino acids (7.6-105%), sugars (20-24%), organic acids (49-121%), phenolic acids (47-315%), and fatty acids (4.2-39%), indicating the boosted respiration and accelerated mobilization of seed stored reserves. Collectively, this simple and inexpensive ($0.62-1.15 per acre) seed priming strategy effectively enhances maize resilience to water and nutrient stress, offering a promising path toward sustainable food security.