WolbachiastrainwAu differs in cellular perturbation and virus inhibition profiles from previously characterisedWolbachiastrains

Some strains of the inherited bacteriumWolbachiahave been shown to be effective at reducing the transmission of dengue and other positive-sense RNA viruses byAedes aegyptiin both laboratory and field settings and are being deployed for dengue control. The degree of virus inhibition varies betweenWolbachiastrains; density and tissue tropism can contribute to these differences but there are also indications that this is not the only factor involved: for example, strainswAu andwAlbA are maintained at similar densities but onlywAu produces strong dengue inhibition. We previously reported perturbations in lipid transport dynamics, including sequestration of cholesterol in lipid droplets, with strainswMel /wMelPop inAe.aegypti. Here we show that strainwAu does not produce the same cholesterol sequestration phenotype despite displaying strong virus inhibition and moreover, in contrast towMel,wAu antiviral activity was not rescued by cyclodextrin treatment. To further investigate the cellular basis underlying these differences, proteomic analysis of midguts was carried out onAe.aegyptilines and revealed thatwAu-carrying midguts showed a distinct proteome when compared toWolbachia-free,wMel- orwAlbA-carrying midguts, in particular with respect to lipid transport and metabolism. The data suggest a possible role for perturbed RNA processing pathways inwAu virus inhibition. Together these results indicate thatwAu shows unique features in its inhibition of arboviruses compared to previously characterizedWolbachiastrains.Author SummaryWolbachiaendosymbionts can block transmission of dengue virus byAedes aegyptimosquitoes, andWolbachiarelease programs for dengue control are now being undertaken in several countries. Understanding the mechanisms ofWolbachia-mediated antiviral activity is important for maximizing the efficacy of this control approach. Using functional and proteomic analyses, this study indicates that different strains ofWolbachiaperturb cellular functions in diverse ways and display different antiviral profiles. These differences raise the possibility thatWolbachiastrain switching could be used to counteract viral escape mutations, should they arise and threaten the efficacy of dengue control programmes.