Functional differentiation of tsetse species microbiota

 描述(申请人提供)：采采蝇是非洲锥虫(Trypanosoma brucei spp.)的循环媒介。它们是致命的人类非洲锥虫病(HAT)的病原体，以及野生和家养动物的Nagana。采采族肠道微生物区系由两种优势细菌组成：古老的专性互惠共生菌Wigglesworth spp.和共生的滑舌藻Sodalis glossinidius。已知媒介能力在采采族之间有所不同，但微生物区系如何影响这种变异仍未被探索。一种普遍的偏见是，微生物区系在不同的采采树物种中扮演着相同的功能角色。这项建议通过确定采采蝇物种微生物区系中的功能差异，并评估这些差异可能如何影响宿主发育、生殖产出和媒介能力，挑战了这一信念。首先，进一步研究了Glossina morsitans(WGM)中的Wigglesworth spp.之间已知的功能差异，即分枝酸和下游叶酸的生物合成能力。将描述寄主发育、妊娠和锥虫挑战期间相关生物合成基因的转录谱，量化细菌体内的叶酸丰度，并确定叶酸代谢中断对采采族生物学和媒介能力的多个方面的影响。其次，将通过两个共生体的同时转录图谱来检验Wigglesworth和Sodalis之间相对于苯丙氨酸生产的代谢整合。将进行中肠内苯丙氨酸丰度的有针对性的量化，并确定钠苯丙氨酸生物合成对采采期适合性和锥虫感染易感性的影响。采采族微生物群之间的这些代谢差异特别耐人寻味，因为莫西坦锥虫是锥虫的多产载体， 和布氏豆腐病菌T.brucei subspp.不能合成叶酸和苯丙氨酸，但需要它们在采采期内发育。最后，下一代测序将用于比较进化上不同的采采子物种--莫西坦采采蝇和短采采蝇的共生体转录本，这两个物种分别代表高媒介能力和低媒介能力的苍蝇物种。这笔赠款中提出的目标将确定共生菌的代谢能力如何有助于采采集生物学和宿主媒介能力的医学上显著的表型变异。从应用的角度来看，对采采集微生物区系的操纵为扩大病媒控制提供了潜在的途径，例如开发针对关键共生菌介导的代谢过程的替代生防技术。

 DESCRIPTION (provided by applicant): Tsetse flies (Diptera: Glossinidae) are the cyclical vectors of African trypanosomes (Trypanosoma brucei spp.) which are the causative agents of fatal Human African Trypanosomiasis (HAT), and Nagana in wild and domesticated animals. The tsetse enteric microbiota consists of two dominant bacteria; the ancient obligate mutualist, Wigglesworthia spp., and the commensal Sodalis glossinidius. Vector competence is known to differ among tsetse species, but how the microbiota may influence this variation remains unexplored. A general preconception is that the microbiota performs identical functional roles within different tsetse species. This proposal challenges this belief by identifying functional differences in the microbiota of tsetse fly species and assessing how these may impact host development, reproductive output and vector competence. First, a known functional distinction between Wigglesworthia spp., the capability for chorismate and downstream folate biosynthesis by Wigglesworthia harbored within Glossina morsitans (Wgm), is further investigated. The transcriptional profiles of relevant biosynthetic loci during host development, pregnancy and trypanosome challenge will be characterized, folate abundance within bacteriomes (organs which house monocultures of Wigglesworthia) quantified, and the impact of folate metabolic disruption towards multiple facets of tsetse biology and vector competency determined. Second, metabolic integration between Wigglesworthia and Sodalis relative to phenylalanine production will be examined through concurrent transcriptional profiling of the two symbionts. Targeted quantification of phenylalanine abundance within midguts will be performed, and the impact of Sodalis phenylalanine biosynthesis towards tsetse fitness and susceptibility to trypanosome infections determined. These metabolic distinctions between the microbiota of tsetse species are particularly intriguing, given the fact that G. morsitans is a prolific vector of trypanosomes, and T. brucei subspp. are unable to synthesize folate and phenylalanine but require these for development within tsetse. Lastly, next generation sequencing will be used to compare the symbiont transcriptomes of two evolutionary divergent tsetse species, G. morsitans and G. brevipalpis, which represent fly species of high and low vector competence, respectively. The aims proposed in this grant will determine how symbiont metabolic capabilities contribute to tsetse biology and medically significant phenotypic variations in host vector competency. From an applied angle, the manipulation of the tsetse microbiota offers potential avenues to amplify vector control, such as the development of alternative biocontrol techniques targeting pivotal symbiont-mediated metabolic processes.