RNA virome diversity and Wolbachia infection in individual Drosophila simulans flies

The endosymbiont bacterium Wolbachia is associated with multiple mutualistic effects on insect biology, including nutritional and antiviral properties. Wolbachia naturally occurs in Drosophila fly species, providing an operational model host to study how virome composition may be impacted by its presence. Drosophila simulans populations can carry a variety of Wolbachia strains. In particular, the wAu strain of Wolbachia has been associated with strong antiviral protection under experimental conditions. We used D. simulans sampled from the Perth Hills, Western Australia, to investigate the potential virus protective effect of the wAu strain on individual wild-caught flies. Our data revealed no appreciable variation in virus composition and abundance between Wolbachia infected/uninfected individuals associated with the presence/absence of wAu. However, it remains unclear whether wAu might impact viral infection and host survival by increasing tolerance rather than inducing complete resistance. These data also provide new insights into the natural virome diversity of D. simulans. Despite the small number of individuals sampled, we identified a repertoire of RNA viruses, including Nora virus, Galbut virus, Chaq virus, Thika virus and La Jolla virus, that have been identified in other Drosophila species. In addition, we identified five novel viruses from the families Reoviridae, Tombusviridae, Mitoviridae and Bunyaviridae. Overall, this study highlights the complex interaction between Wolbachia and RNA virus infections and provides a baseline description of the natural virome of D. simulans.