miRNA dynamics in the understudied vector, Culicoides sonorensis

Culicoides sonorensis midges vector multiple livestock arboviruses, such as bluetongue virus, epizootic hemorrhagic disease virus, and vesicular stomatitis virus, resulting in significant economic losses worldwide. Due to the tight association between disease transmission, blood feeling, and egg development, understanding midge physiology is critical to develop more targeted control strategies. Multiple studies have demonstrated the importance of small non-coding RNAs (ncRNAs) in several aspects of vector physiology. Indeed, most work has focused on microRNAs (miRNAs), which regulate gene expression at the post-transcriptional level. To determine the miRNA catalog within Culicoides, we took a next generation sequencing approach. Using small RNA-Seq and miRDeep2 analyses, we characterized the miRNA transcriptome in both whole insects and midgut tissues before and after blood feeding. Our analyses revealed (i) orthologous, (ii) Culicoides-specific, (iii) tissue-enriched, and (iv) blood-meal induced miRNAs. Of the latter point, we also identified a conserved cluster of miRNAs whose expression follows the gonotrophic cycle. These data provide a necessary foundation for future ncRNA work to untangle the dynamics of gene regulation associated with midge physiology and disease transmission.