Contrasting Patterns of Virus Protection and Functional Incompatibility Genes in Two ConspecificWolbachiaStrains fromDrosophila pandora
ABSTRACTWolbachiainfections can present different phenotypes in hosts, including different forms of reproductive manipulation and antiviral protection, which may influence infection dynamics within host populations. In populations ofDrosophila pandoratwo distinctWolbachiastrains coexist, each manipulating host reproduction: strainwPanCI causes cytoplasmic incompatibility (CI), whereas strainwPanMK causes male killing (MK). CI occurs when aWolbachia-infected male mates with a female not infected with a compatible type ofWolbachia, leading to nonviable offspring.wPanMK can rescuewPanCI-induced CI but is unable to induce CI. The antiviral protection phenotypes provided by thewPanCI andwPanMK infections were characterized; the strains showed differential protection phenotypes, whereby cricket paralysis virus (CrPV)-induced mortality was delayed in flies infected withwPanMK but enhanced in flies infected withwPanCI compared to their respectiveWolbachia-cured counterparts. Homologs of thecifAandcifBgenes involved in CI identified inwPanMK andwPanCI showed a high degree of conservation; however, the CifB protein inwPanMK is truncated and is likely nonfunctional. The presence of a likely functional CifA inwPanMK andwPanMK’s ability to rescuewPanCI-induced CI are consistent with the recent confirmation of CifA’s involvement in CI rescue, and the absence of a functional CifB protein further supports its involvement as a CI modification factor. Taken together, these findings indicate thatwPanCI andwPanMK have different relationships with their hosts in terms of their protective and CI phenotypes. It is therefore likely that different factors influence the prevalence and dynamics of these coinfections in naturalDrosophila pandorahosts.IMPORTANCEWolbachiastrains are common endosymbionts in insects, with multiple strains often coexisting in the same species. The coexistence of multiple strains is poorly understood but may rely onWolbachiaorganisms having diverse phenotypic effects on their hosts. AsWolbachiais increasingly being developed as a tool to control disease transmission and suppress pest populations, it is important to understand the ways in which multipleWolbachiastrains persist in natural populations and how these might then be manipulated. We have therefore investigated viral protection and the molecular basis of cytoplasmic incompatibility in two coexistingWolbachiastrains with contrasting effects on host reproduction.