High-Efficiency and Eco-Friendly Management of Multiple Fungal Diseases by a Novel Carbon Dots sCDP Delivered RNA Nano-Pesticides.

RNA-based pesticides represent a transformative approach in agricultural disease management, offering an environmentally sustainable alternative to conventional chemical fungicides. However, key challenges such as rapid RNA degradation in the environment and inefficient uptake hinder widespread adoption. Nanocarriers have the potential to significantly enhance RNA delivery efficiency and stability, which holds great promise for developing eco-friendly strategies in crop protection. Here, we developed a novel multicomponent nano-biopesticide platform utilising novel polyethyleneimine-modified carbon dots (sCDP) for dsRNA delivery. It was demonstrated that sCDP forms stable electrostatic complexes with dsRNA (sCDP-dsRNA), conferring dual protective advantages and enhanced RNA stability with extended foliar persistence exceeding 14 days. Moreover, the sCDP can significantly reduce the contact angle of dsRNA on the leaf surface, and the complexation of sCDP with dsRNA remarkably enhances uptake efficiency into plant leaves and pathogens' mycelium, thereby enhancing plant protection of RNA pesticides. Additionally, sCDP exhibits good biocompatibility and low toxicity against pathogens and plants. Finally, it was demonstrated that sCDP-dsRNA complexes showed significant efficacy in preventing and treating rice sheath blight, both in laboratory and field conditions. Moreover, the platform demonstrated broad-spectrum antifungal activity against four major pathogens including Aspergillus niger, Botrytis cinerea, Magnaporthe oryzae, and Phakopsora pachyr under different conditions. Thus, this nanoplatform establishes an efficient and environmentally sustainable crop protection paradigm by synergizing the precision of RNA interference with enhanced delivery capabilities.