RNAi knockdowns support a role for the mucin-like (AeIMUC1) gene and short-chain dehydrogenase/reductase (SDR) gene in Aedes aegypti susceptibility to Plasmodium gallinaceum

摘要

The mosquito midgut represents the first barrier that the Plasmodium parasite encounters after blood ingestion from an infected vertebrate. Previous studies identified the Aedes aegypti (L.) mucin-like (AeIMUC1) and short-chain dehydrogenase/reductase (SDR) genes as midgut-expressed candidate genes influencing susceptibility to infection by Plasmodium gallinaceum (Brumpt). Here we used RNA inference (RNAi) by double-stranded RNA injections (dsRNA) to examine ookinete survival to the oocyst stage following individual gene knockdowns. dsRNA gene knockdowns were performed three days prior to P. gallinaceum infections and oocyst development was evaluated at seven days post infection. Mean numbers of parasites developing to the oocyst stage were significantly reduced by 52.3% among dsAeIMUC1 injected females and by 36.5% among dsSDR infected females compared to females injected with a dsβ-gal control. Prevalence of infection was significantly reduced among dsAeIMUC1 and dsSDR injected females compared to females injected with a dsβ-gal control; this represented a two and three fold increase in the number of uninfected individuals, respectively. Overall, these results suggest that both AeIMUC1 and SDR play a role in Ae. aegypti vector competence to P. gallinaceum.