Wolbachia strain w Pip yields a pattern of cytoplasmic incompatibility enhancing a Wolbachia- based suppression strategy against the disease vector Aedes albopictus

Abstract

BackgroundCytoplasmic incompatibility (CI) is induced in nature by Wolbachia bacteria, resulting in conditional male sterility. Previous research demonstrated that the two Wolbachia strains (wAlbA and wAlbB) that naturally co-infect the disease vector mosquito Aedes albopictus (Asian tiger mosquito) can be replaced with the wPip Wolbachia strain from Culex pipiens. Since Wolbachia-based vector control strategies depend upon the strength and consistency of CI, a greater understanding is needed on the CI relationships between wPip, wAlbA and wAlbB Wolbachia in Ae. albopictus.MethodsThis work consisted of a collaborative series of crosses carried out in Italy and in US to study the CI relationships between the “wPip” infected Ae. albopictus strain (ARwP) and the superinfected SR strain. The Ae. albopictus strains used in Italian tests are the wPip infected ARwP strain (ARwPIT), the superinfected SR strain and the aposymbiotic AR strain. To understand the observed pattern of CI, crossing experiments carried out in USA focused on the study of the CI relationships between ARwP (ARwPUS) and artificially-generated single infected lines, in specific HTA and HTB, harbouring only wAlbA and wAlbB Wolbachia respectively.ResultsThe paper reports an unusual pattern of CI observed in crossing experiments between ARwP and SR lines. Specifically, ARwP males are able to induce full sterility in wild type females throughout most of their lifetime, while crosses between SR males and ARwP females become partially fertile with male aging. We demonstrated that the observed decrease in CI penetrance with SR male age, is related to the previously described decrease in Wolbachia density, in particular of the wAlbA strain, occurring in aged superinfected males.ConclusionsThe results here reported support the use of the ARwP Ae. albopictus line as source of “ready-made sterile males”, as an alternative to gamma radiation sterilized males, for autocidal suppression strategies against the Asian tiger mosquito. In addition, the age dependent CI weakening observed in the crosses between SR males and ARwP females simplifies the downstream efforts to preserve the genetic variability within the laboratory ARwP colonies, to date based on the antibiotic treatment of wild captured superinfected mosquitoes, also reducing the costs.

Distribution and dynamics of Wolbachia infection in Malaysian Aedes albopictus

“…aegypti (Xi et al, 2005;Ruang-Areerate and Kittayapong, 2006;Bian et al, 2010) and some on artificially infected Ae .albopictus with wMel strain (Blagrove et al, 2012;Calvitti et al, 2012).…”

Back and forth Wolbachia transfers reveal efficient strains to control spotted wing drosophila populations

“…Notably, the fact that the w Ha and w Tei strains are mutually incompatible (Zabalou et al., ) means that one strain might still be used for population control in case of accidental release and invasion of the first strain. To circumvent the difficult sexing step, IIT could be coupled with moderate irradiation (Bourtzis et al., ; Brelsfoard, St Clair, & Dobson, ; Zhang, Zheng, Xi, Bourtzis, & Gilles, ) that would be sufficient to sterilize females without affecting the life‐history traits and competitiveness of males which would be fully sterile due to the Wolbachia (Bourtzis et al., ; Calvitti, Moretti, Skidmore, & Dobson, ). Finally, IIT relies on the massive production of males, which seems achievable for such a small and polyphagous insect, but requires additional developments.…”

Diversity and function of bacterial microbiota in the mosquito holobiont

“…To face these outbreaks, new control strategies based on manipulation of the mosquito hosts and their microbial partners have been proposed recently [15]. A well-known example of this in action is the use of the endosymbiotic bacterium Wolbachia [16,17]. This bacterium has a direct impact on the development of some mosquito species by shortening the insect life span, and has indirect effects interfering with pathogen replication and dissemination that affect the vector transmission ability [18,19].…”