Chitosan nanoparticle-mediated delivery of dsRNA for enhancing RNAi efficiency in Locusta migratoria.

Background: RNA interference (RNAi) targeting the key genes involved in insect growth and development has been demonstrated as pollution-free green pest management strategies. Double-stranded RNA (dsRNA)-based biopesticides offer species-specific pest control and degrade rapidly in the environment, making them a safer alternative to conventional chemical pesticides. However, efficient delivery of dsRNA is a significant challenge in the application of RNAi technology for pest management.

Results: Chitosan, a natural biopolymer, was selected to generate nanoparticles with dsRNA of LmCht10, which is responsible for chitin degradation, for delivery of dsLmCht10 in Locusta migratoria. Compared with the naked dsLmCht10, application of chitosan/dsLmCht10 nanoparticles enhanced the stability of dsRNA in the locust gut fluid in vitro. Feeding the locusts with chitosan/dsLmCht10 nanoparticles resulted in a 67% decrease of LmCht10 transcripts and a 2-fold increase in locust mortality. Injection of chitosan/dsLmCht10 into the locust body cavity substantially improved RNAi efficiency against LmCht10 by 96.6% associated with a 2-fold increase in locust mortality. In addition, the absorption of chitosan/dsLmCht10 nanoparticles by locust epidermal cells increased significantly and continuously by 7.3 to 8.3 times.

Conclusion: This study has demonstrated that chitosan-based dsRNA nanomaterials can significantly improve the stability of dsRNA in the midgut fluid, enhance RNAi efficiency, and increase insect mortality. Moreover, chitosan-based dsRNA delivery enhances silencing efficiency by increasing the uptake of dsRNA in the epidermal cells. Our results suggest that the use of chitosan nanomaterial for dsRNA delivery is a feasible strategy for advancing the application of RNAi technology in pest management. © 2025 Society of Chemical Industry.