Exploiting the Conflict Within: Examining Tripartite Interactions for Development of Next Generation Mosquito Microbiome Vector Control Strategies.

Mosquitoes harbor various microbes that profoundly influence many aspects of their biology, including vector competence. Given their intimate association, these microbes have established a wide range of strategies aiding them in their transmission, either horizontally or vertically, making them highly attractive for applied vector control approaches to prevent the spread of arthropod-borne disease. The mosquito microbiome responds to environmental and host cues as well as microbial interactions and diet. This body of work focuses on a number of aspects import for the development of a robust microbial driven control stratagem. Next generation sequencing of the 16S ribosomal RNA gene was utilized to examine the microbiome in each of the objectives presented here. The first objective explored how different sugar types influence the microbiome of Aedes aegypti resulted in two main conclusions. First, mosquitoes that are reared in separarte environments had distinct microbiomes. The second finding was that, although sugar type only impatcted the overall microbial community structure in the New Orleans mosquito line from Liverpool, the Galveston mosquito line from Galveston and the NO line from Liverpool both experienced altered responses to each sugar by specific bacterial taxa. The second objective characterized the relationship between the microbiome and Zika virus (ZIKV) in both lab reared and field collected Ae. aegypti mosquitoes. Here bacterial representatives of the Acetobacteraceae and Enterobacteriaceae families were correlated to ZIKV infection. The influence of these bacteria was found to be independent of mosquito immunity. Additionally, mosquitoes exposed to ZIKV had increased levels of these Acetobacteraceae and Enterobacteriaceae bacteria. These results suggest that ZIKV infection were both mosquito and viral strain specific. The third objective, which examines host small RNA interplay between mosquitoes and ZIKV infection, found that infection lead to dramatic increases in short interfering RNAs (siRNAs) and PIWI-interacting RNAs (piRNAs). Additionally, 17 host miRNAs had altered levels across multiple time points. Finally, the mosquito RNAi response to ZIKV targeted the NS5 region, while ZIKV in response produced virus-derived piRNA-like small RNAs (vipRNAs). Together, these results establish the foundations for developing a microbial based control strategy, in which bacteria could be engineered to deliver RNAi-stimulating RNAs in mosquito hosts to prevent the spread of arboviruses like ZIKV.