Chitosan/double-stranded RNA nanoparticle-mediated RNA interference to silence chitin synthase genes through larval feeding in the African malaria mosquito (Anopheles gambiae)

The purpose of this study was to examine whether the expression of two chitin synthase genes, AgCHS1 and AgCHS2, can be repressed by chitosan/AgCHS dsRNA-based nanoparticles through larval feeding in Anopheles gambiae. The AgCHS1 transcript level and chitin content were reduced by 62.8 and 33.8%, respectively, in the larvae fed on chitosan/AgCHS1 dsRNA nanoparticles compared with those of the control larvae fed on chitosan/GFP dsRNA nanoparticles. Our study suggested for the first time that RNA interference (RNAi) in mosquito larvae is systemic, and demonstrated that the larvae fed on the nanoparticles assembled from AgCHS1 and AgCHS2 dsRNA increased larval susceptibilities to diflubenzuron, and calcofluor white (CF) or dithiothreitol, respectively. These results suggest great potential for using such a nanoparticle-based RNAi technology for high-throughput screening of gene functions and for developing novel strategies for pest management.