WolbachiastrainwMel induces cytoplasmic incompatibility and blocks dengue transmission inAedes albopictus

Abstract

Wolbachia inherited bacteria are able to invade insect populations using cytoplasmic incompatibility and provide new strategies for controlling mosquito-borne tropical diseases, such as dengue. The overreplicatingwMelPop strain was recently shown to strongly inhibit the replication of dengue virus when introduced intoAedes aegyptimosquitoes, as well as to stimulate chronic immune up-regulation. Here we show that stable introduction of thewMel strain ofDrosophila melanogasterintoAedes albopictus, a vector of dengue and other arboviruses, abolished the transmission capacity of dengue virus-challenged mosquitoes. Immune up-regulation was observed in the transinfected line, but at a much lower level than that previously found for transinfectedAe. aegypti. Transient infection experiments suggest that this difference is related toAe. albopictusimmunotolerance ofWolbachia, rather than to theWolbachiastrain used. This study provides an example of strong pathogen inhibition in a naturallyWolbachia-infected mosquito species, demonstrating that this inhibition is not limited to naturally naïve species, and suggests that theWolbachiastrain is more important than host background for viral inhibition. Complete bidirectional cytoplasmic incompatibility was observed with WT strains infected with the naturally occurringAe. albopictus Wolbachia, and this provides a mechanism for introducingwMel into natural populations of this species.