Deciphering Drosophila immune resistance to endoparasitoid wasps: mechanisms, specificity and evolution

Drosophila melanogaster is a model organism for many fields in biology including immunology.Drosophila innate immunity is well described in case of bacterial and fungal infections but otherparasites, such as parasitoids, can be harmful and even lethal to Drosophila.We are working on the immune interaction between Drosophila larvae and the endoparasitic wasp,Leptopilina boulardi, a species that lay eggs inside Drosophila larvae. The parasitoid larval stages thendevelop at the expense of the host leading to its death. The adult parasitoid emerges from theDrosophila pupa.Drosophila larvae recognizes the parasitoid egg as a foreign body and, depending on the fly strain, theycan mount a successful immune response: the egg is surrounded by layers of hemocytes forming amelanized capsule, and it is a fly that will emerge. To counteract the immune response, female waspsrely on venom components injected together with the egg which prevent the encapsulation.A major biallelic gene (alleles R and S) responsible for the resistance / susceptibility of Drosophila to L.boulardi has been identified. I am involved in deciphering the role of this gene in the resistancemechanism using different approaches including: Flow cytometry to track the variation in quantity /proportion of the different types of hemocytes following parasitism; Bioinformatics to identifypotential interactants of this gene; Mutants and strains UAS-RNAi to understand the potential role ofthese genes in the anti-parasitic immune defence of Drosophila.