Exogenously Applied Double-stranded RNAs: A Novel Strategy to Trigger RNA Silencing for Sustainable Plant Disease Management

The emergence of plant diseases poses a significant threat to global food security and agricultural sustainability. Conventional management strategies, including chemical pesticides, often lead to environmental threats and human health concerns, while cultural practices frequently exhibit limited efficacy. Furthermore, the unavailability of resistant sources, particularly against viral pathogens, necessitates the development of innovative control measures. RNA interference (RNAi), a highly specific gene silencing mechanism, has emerged as a promising approach for plant disease management. Among RNAi-based strategies, the exogenous application of synthetic double-stranded RNAs (ds-RNAs) has gained attention for its ability to induce RNA silencing in pathogens. This approach involves the delivery of ds-RNAs designed to target essential pathogen genes, leading to sequence-specific suppression upon uptake. Foliar spraying and mechanical application have been employed as effective delivery methods, while advancements in nanotechnology have enhanced ds-RNA stability, uptake efficiency, and persistence under field conditions. Several studies have demonstrated the efficacy of exogenous ds-RNA applications in mitigating disease severity and enhancing plant resistance across diverse patho-systems. Experimental results demonstrate a significant reduction in disease severity, with dsRNA applications leading to a 60–80% decrease in pathogen proliferation, depending on the crop-pathogen system. The findings highlight the potential of dsRNA-based strategies as an environmentally friendly alternative to conventional chemical fungicides. However, challenges remain in optimizing ds-RNA design, improving uptake efficiency, addressing environmental persistence, and establishing regulatory frameworks for field deployment. Despite these challenges, exogenous RNAi represents a sustainable and environmentally safe alternative to conventional chemical control methods, particularly in cases where genetic resistance is unavailable, offering a novel paradigm for plant disease management. Future research should explore enhanced delivery mechanisms and synergistic combinations with other biocontrol agents. Ultimately, this study underscores the transformative potential of dsRNA technology in sustainable agriculture, paving the way for more targeted and eco-friendly plant disease management strategies.