Wolbachia Enhance Drosophila Stem Cell Proliferation and Target the Germline Stem Cell Niche

Abstract

Wolbachia are widespread maternally-transmitted intracellular bacteria that infect most insect species and are able to alter the reproduction of innumerous hosts. The cellular bases of these alterations remain largely unknown. Here we report that Drosophila mauritiana infected with a native Wolbachia wMau strain produces about four times more eggs than the non-infected counterpart. Wolbachia infection leads to an increase in the mitotic activity of germline stem cells (GSCs) as well as a decrease in programmed cell death in the germarium. Our results suggest that upregulation of GSCs division is mediated by a tropism of Wolbachia for the germline stem cell niche (GSCN), the cellular microenvironment that supports GSCs.

Cytoplasmic incompatibility and fitness benefits in the two-spotted spider mite Tetranychus urticae (red form) doubly infected with Wolbachia and Cardinium

“…The possible mechanisms underlying these effects are still unclear. Wolbachia infection in Drosophila mauritiana leads to increase mitotic activity of germline stem cells and to decrease apoptosis in the germarium (Fast et al 2011). Cardinium probably affects host fecundity in a similar way.…”

Evolutionarily conserved Wolbachia -encoded factors control pattern of stem-cell niche tropism in Drosophila ovaries and favor infection

“…GSCN tropism was defined as Wolbachia accumulation in the TF and CCs, as previously described (18). Fly stocks utilized in this study, husbandry, immunohistochemistry, FISH, introgression crosses, phylogenetic analyses, image analysis, FtsZ analysis, and statistical analysis are provided in SI Appendix, Supplemental Materials and Methods.…”

“…Additionally, in another fruit fly, Drosophila mauritiana, Wolbachia also target the germ-line stem-cell niche (GSCN; Fig. 1A, green cells) in long-term maternally infected flies (18). The GSCN is a somatic structure at the anterior tip of the germarium, composed of terminal filament (TF) and cap cells (CC) ( Fig.…”

Genome comparisons indicate recent transfer ofwRi‐likeWolbachiabetween sister speciesDrosophila suzukiiandD. subpulchrella

“…For example, the most common Wolbachia reproductive manipulation is CI, in which, embryos produced by uninfected females mated with infected males suffer increased mortality. Because CI is essentially irrelevant to the frequency dynamics of rare infections, initial spread of both CI‐causing infections and infections that do not manipulate reproduction is likely to be driven by mutualistic effects such as fecundity enhancement (Fast et al., 2011; Weeks et al., 2007), protection from viruses (Teixeira, Ferreira, & Ashburner, 2008), or metabolic provisioning (Brownlie et al., 2009). …”