A <i>w</i> AlbB <i>Wolbachia</i> Transinfection Displays Stable Phenotypic Effects across Divergent Aedes aegypti Mosquito Backgrounds

Abstract

<i>Aedes</i> mosquitoes harboring intracellular <i>Wolbachia</i> bacteria are being released in arbovirus and mosquito control programs. With releases taking place around the world, understanding the contribution of host variation to <i>Wolbachia</i> phenotype is crucial. We generated a <i>Wolbachia</i> transinfection (<i>w</i>AlbB^Q) in Aedes aegypti and performed backcrossing to introduce the infection into Australian or Malaysian nuclear backgrounds. Whole <i>Wolbachia</i> genome sequencing shows that the <i>w</i>AlbB^Q transinfection is nearly identical to the reference <i>w</i>AlbB genome, suggesting few changes since the infection was first introduced to A. aegypti over 15 years ago. However, these sequences were distinct from other available <i>w</i>AlbB genome sequences, highlighting the potential diversity of <i>w</i>AlbB in natural Aedes albopictus populations. Phenotypic comparisons demonstrate the effects of <i>w</i>AlbB infection on egg hatching and nuclear background on fecundity and body size but no interactions between <i>w</i>AlbB infection and nuclear background for any trait. The <i>w</i>AlbB infection was stable at high temperatures and showed perfect maternal transmission and cytoplasmic incompatibility regardless of the host background. Our results demonstrate the stability of <i>w</i>AlbB across host backgrounds and point to its long-term effectiveness for controlling arbovirus transmission and mosquito populations. <b>IMPORTANCE</b><i>Wolbachia</i> bacteria are being used to control the transmission of dengue virus and other arboviruses by mosquitoes. For <i>Wolbachia</i> release programs to be effective globally, <i>Wolbachia</i> infections must be stable across mosquito populations from different locations. In this study, we transferred <i>Wolbachia</i> (strain <i>w</i>AlbB) to Aedes aegypti mosquitoes with an Australian genotype and introduced the infection to Malaysian mosquitoes through backcrossing. We found that the phenotypic effects of <i>Wolbachia</i> are stable across both mosquito backgrounds. We sequenced the genome of <i>w</i>AlbB and found very few genetic changes despite spending over 15 years in a novel mosquito host. Our results suggest that the effects of <i>Wolbachia</i> infections are likely to remain stable across time and host genotype.