Medina Munoz Miguel, Pollio Adam R, White Hunter L, Rio Rita V M
Department of Biology, Eberly College of Arts and Sciences, West Virginia University, Morgantown, WV.
Genome Biol Evol. 2017 Sep 1;9(9):2276-2291. doi: 10.1093/gbe/evx175.
Tsetse flies (Diptera: Glossinidae) have medical significance as the obligate vectors of African trypanosomes. In addition, tsetse harbor a simple gut microbiota. A predominant gut microbiota member, the Gammaproteobacterium Wigglesworthia spp., has coevolved with tsetse for a significant portion of Glossina radiation proving critical to tsetse fitness. Although multiple roles have been described for Wigglesworthia within colony flies, little research has been dedicated towards functional characterization within wild tsetse. Here, dual RNA-Seq was performed to characterize the tsetse-Wigglesworthia symbiosis within flies captured in Nguruman, Kenya. A significant correlation in Gene Ontology (GO) distribution between tsetse and Wigglesworthia was observed, with homogeneous enrichment in metabolic and transport categories, likely supporting a hallmark of the symbiosis-bidirectional metabolic exchange. Within field flies, highly transcribed Wigglesworthia loci included those involved in B vitamin synthesis and in substrate translocation, including amino acid transporters and multidrug efflux pumps, providing a molecular means for interaction. The universal expression of several Wigglesworthia and G. pallidipes orthologs, putatively involved in nutrient provisioning and resource allocation, was confirmed in sister tsetse species. These transcriptional profiles varied through host age and mating status likely addressing varying symbiont demands and also confirming their global importance within Glossina. This study, not only supports symbiont nutrient provisioning roles, but also serves as a foundation for insight into novel roles and molecular mechanisms associated with vector-microbiota interactions. The role of symbiont B vitamin provisioning towards impacting host epigenetics is discussed. Knowledge of vector-microbiota interactions may lead to the discovery of novel targets in pest control.
采采蝇（双翅目：舌蝇科）作为非洲锥虫的专性传播媒介具有医学重要性。此外，采采蝇体内存在简单的肠道微生物群。肠道微生物群的主要成员——γ-变形菌属的维氏菌属（Wigglesworthia spp.），在采采蝇的大部分进化辐射过程中与采采蝇共同进化，对采采蝇的适应性至关重要。尽管已描述了维氏菌属在圈养采采蝇中的多种作用，但针对野生采采蝇的功能特性研究较少。在此，进行了双RNA测序，以表征在肯尼亚恩古兰曼捕获的采采蝇体内采采蝇与维氏菌属的共生关系。观察到采采蝇和维氏菌属之间在基因本体（GO）分布上存在显著相关性，在代谢和转运类别中均有均匀富集，这可能支持了共生关系的一个标志——双向代谢交换。在野外采采蝇中，高度转录的维氏菌属基因座包括参与B族维生素合成和底物转运的基因座，如氨基酸转运体和多药外排泵，这为相互作用提供了分子手段。在采采蝇姐妹物种中证实了几种推测参与营养供应和资源分配的维氏菌属和淡足采采蝇（G. pallidipes）直系同源基因的普遍表达。这些转录谱因宿主年龄和交配状态而异，可能满足共生体不同的需求，也证实了它们在采采蝇属中的全球重要性。本研究不仅支持共生体的营养供应作用，还为深入了解与媒介-微生物群相互作用相关的新作用和分子机制奠定了基础。讨论了共生体B族维生素供应对宿主表观遗传学的影响。对媒介-微生物群相互作用的了解可能会促成害虫防治新靶点的发现。
