Development of an efficient recombinant mosquito densovirus-mediated RNA interference system and its preliminary application in mosquito control.

The Aedes aegypti densovirus (AeDNV) has potential as a delivery vector for foreign nucleic acids into mosquito cells. In this study, we investigated the ability of plasmids containing recombinant viral transducing genome to induce RNA interference (RNAi) effects in C6/C36 cells. We then evaluated the efficiency of a recombinant AeDNV vector to induce RNAi in Aedes albopictus larvae. We found that the expression of V-ATPase was inhibited by up to 90% at 96 h post-transfection in transfected C6/C36 cells. In addition, the bioinsecticidal activities of various RNAi-expressing AeDNV vectors used to infect Ae. albopictus larvae were also tested. We found that when Ae. albopictus larvae were infected with recombinant AeDNV, expression of V-ATPase was downregulated by nearly 70% compared to controls. Furthermore, the median survival time bioassays demonstrated that recombinant AeDNV caused more serious pathogenic effects than the wild type virus. This is the first report showing that recombinant virus plasmid and corresponding recombinant AeDNV can be used as an effective in vitro and in vivo RNAi delivery system, respectively.