Department of Biology, West Virginia University, Morgantown, West Virginia, USA.
J Bacteriol. 2013 Oct;195(19):4322-30. doi: 10.1128/JB.00487-13. Epub 2013 Jul 8.
Microbial symbionts can be instrumental to the evolutionary success of their hosts. Here, we discuss medically significant tsetse flies (Diptera: Glossinidae), a group comprised of over 30 species, and their use as a valuable model system to study the evolution of the holobiont (i.e., the host and associated microbes). We first describe the tsetse microbiota, which, despite its simplicity, harbors a diverse range of associations. The maternally transmitted microbes consistently include two Gammaproteobacteria, the obligate mutualists Wigglesworthia spp. and the commensal Sodalis glossinidius, along with the parasitic Alphaproteobacteria Wolbachia. These associations differ in their establishment times, making them unique and distinct from previously characterized symbioses, where multiple microbial partners have associated with their host for a significant portion of its evolution. We then expand into discussing the functional roles and intracommunity dynamics within this holobiont, which enhances our understanding of tsetse biology to encompass the vital functions and interactions of the microbial community. Potential disturbances influencing the tsetse microbiome, including salivary gland hypertrophy virus and trypanosome infections, are highlighted. While previous studies have described evolutionary consequences of host association for symbionts, the initial steps facilitating their incorporation into a holobiont and integration of partner biology have only begun to be explored. Research on the tsetse holobiont will contribute to the understanding of how microbial metabolic integration and interdependency initially may develop within hosts, elucidating mechanisms driving adaptations leading to cooperation and coresidence within the microbial community. Lastly, increased knowledge of the tsetse holobiont may also contribute to generating novel African trypanosomiasis disease control strategies.
微生物共生体可以成为其宿主进化成功的关键。在这里，我们讨论了具有医学意义的采采蝇（双翅目：舌蝇科），这是一个由 30 多种物种组成的群体，它们被用作研究整个共生体（即宿主和相关微生物）进化的有价值的模型系统。我们首先描述了采采蝇微生物组，尽管其结构简单，但却拥有广泛的关联。通过母系遗传的微生物始终包括两种γ变形菌，即必需的共生菌 Wigglesworthia 属和共生菌 Sodalis glossinidius，以及寄生的α变形菌 Wolbachia。这些关联在建立时间上有所不同，使它们与以前描述的共生关系不同，在以前的共生关系中，多个微生物伙伴与宿主的进化过程中的很大一部分相关联。然后，我们扩展到讨论这个整个共生体中的功能角色和群落内动态，这增强了我们对采采蝇生物学的理解，包括微生物群落的重要功能和相互作用。强调了可能影响采采蝇微生物组的潜在干扰因素，包括唾液腺肥大病毒和锥虫感染。虽然以前的研究已经描述了宿主关联对共生体的进化后果，但促进它们纳入整个共生体和整合伙伴生物学的初始步骤才刚刚开始探索。对采采蝇整个共生体的研究将有助于理解微生物代谢整合和相互依存性最初如何在宿主中发展，阐明导致共生体中合作和共存的适应机制。最后，增加对采采蝇整个共生体的了解也可能有助于制定新的非洲锥虫病控制策略。
