Convergent origin and accelerated evolution of vesicle-associated RhoGAP proteins in two unrelated parasitoid wasps

Gene duplication, accompanied by modification of the expression and/or function of one of the duplicates under the action of positive selection, followed by further duplication to produce multigene families of toxins is a well-documented process in venomous animals. This evolutionary model has been less described in parasitoid wasps, which use maternal fluids, including venom, to protect their eggs from encapsulation by the host immune system. The leptopilina venom proteomic data were used to evidence that specific RhoGAPs formed a family of protein that are associated with vesicles that act as transport systems to deliver them in the immune cells of their drosophila larval host. We showed that the gene encoding the cellular RacGAP1 is at the origin of the virulent RhoGAP family formed by successive duplications that evolved under positive selection. Almost all of these RhoGAPs lost their GAP activity and GTPase binding ability due to mutations in key amino acids suggesting new function(s) and mechanism of action in host cells that remain to be elucidated.