Expression of a mutated phospholipase A₂ in transgenic Aedes fluviatilis mosquitoes impacts Plasmodium gallinaceum development

The genetic manipulation of mosquito vectors is an alternative strategy in the fight against malaria. It was previously shown that bee venom phospholipase A₂ (PLA₂) inhibits ookinete invasion of the mosquito midgut although mosquito fitness was reduced. To maintain the PLA₂ blocking ability without compromising mosquito biology, we mutated the protein-coding sequence to inactivate the enzyme while maintaining the protein's structure. DNA encoding the mutated PLA₂ (mPLA₂) was placed downstream of a mosquito midgut-specific promoter (Anopheles gambiae peritrophin protein 1 promoter, AgPer1) and this construct used to transform Aedes fluviatilis mosquitoes. Four different transgenic lines were obtained and characterized and all lines significantly inhibited Plasmodium gallinaceum oocyst development (up to 68% fewer oocysts). No fitness cost was observed when this mosquito species expressed the mPLA₂.