Wolbachia and virus alter the host transcriptome at the interface of nucleotide metabolism pathways

Wolbachia is a maternally transmitted bacterium that manipulates arthropod and nematode biology in myriad ways. The Wolbachia strain colonizing Drosophila melanogaster creates sperm-egg incompatibilities and protects its host against RNA viruses, making it a promising tool for vector control. Despite successful trials using Wolbachia-transfected mosquitoes for Dengue control, knowledge of how Wolbachia and viruses jointly affect insect biology remains limited. Using the Drosophila melanogaster model, transcriptomics and gene expression network analyses revealed pathways with altered expression and splicing due to Wolbachia colonization and virus infection. Included are metabolic pathways previously unknown to be important for Wolbachia-host interactions. Additionally, Wolbachia-colonized flies exhibit a dampened transcriptomic response to virus infection, consistent with early blocking of virus replication. Finally, using Drosophila genetics, we show Wolbachia and expression of nucleotide metabolism genes have interactive effects on virus replication. Understanding the mechanisms of pathogen blocking will contribute to the effective development of Wolbachia-mediated vector control programs. To determine the effect of Wolbachia and virus infection on fly gene expression, we established in vivo systemic viral infections in adult Drosophila, using a block design with a time series. Flies with or without Wolbachia (W+/W-), were injected with either virus or saline (SINV+/SINV-), and collected at 6, 24, and 48 hours post-injection (hpi). For each unique condition of W-SINV-time, we generated four biological replicates (A-D), with each replicate consisting of a pool of five virgin females. In total, 48 libraries were generated.