Exogenous dsRNA-mediated plant protection: innovations in synthesis, nanodelivery, and fungal disease management

Fungal pathogens represent a persistent and evolving threat to global food security, causing substantial yield losses in staple crops annually. Simultaneously, the ecological and environmental risks associated with the prolonged reliance on synthetic fungicides have necessitated an urgent search for sustainable, biorational alternatives. Exogenous double-stranded RNA (dsRNA)-mediated Spray-Induced Gene Silencing (SIGS) has emerged as a promising RNA-based plant protection strategy, offering a sequence-guided and environmentally degradable approach for fungal disease management. This review summarizes recent progress and key translational barriers in exogenous dsRNA-based fungal disease control, with particular emphasis on production, delivery, stability, uptake, and field applicability. We compare major dsRNA production platforms, including in vitro transcription, microbial fermentation, cell-free biosynthesis, and minicell-based systems, with attention to scalability, cost, purity, and formulation compatibility. We further discuss cross-kingdom RNAi trafficking and the biological factors that influence dsRNA uptake and silencing efficiency in fungal pathogens. In addition, we evaluate nanodelivery strategies designed to improve dsRNA stability, leaf retention, controlled release, and plant or pathogen uptake. Despite demonstrated success in various pathosystems, widespread commercial translation remains constrained by production cost, formulation stability, environmental degradation, inconsistent uptake efficiency, limited field validation, potential non-target and microbiome effects, resistance evolution, and evolving regulatory requirements. Future research should prioritize standardized field evaluation, mechanism-guided carrier design, multi-target resistance management, biosafety assessment, and integration of SIGS into Integrated Pest Management strategies. These efforts will be essential for translating SIGS into precise, effective, and sustainable plant disease management.