Microbiota of Insect Vectors Group, Institut Pasteur de la Guyane, Cayenne, French Guiana, France.
Institute for Infectious Diseases, University of Bern, Bern, Switzerland.
Nat Commun. 2021 Feb 11;12(1):942. doi: 10.1038/s41467-021-21195-3.
The mosquito microbiota impacts the physiology of its host and is essential for normal larval development, thereby influencing transmission of vector-borne pathogens. Germ-free mosquitoes generated with current methods show larval stunting and developmental deficits. Therefore, functional studies of the mosquito microbiota have so far mostly been limited to antibiotic treatments of emerging adults. In this study, we introduce a method to produce germ-free Aedes aegypti mosquitoes. It is based on reversible colonisation with bacteria genetically modified to allow complete decolonisation at any developmental stage. We show that, unlike germ-free mosquitoes previously produced using sterile diets, reversibly colonised mosquitoes show no developmental retardation and reach the same size as control adults. This allows us to uncouple the study of the microbiota in larvae and adults. In adults, we detect no impact of bacterial colonisation on mosquito fecundity or longevity. In larvae, data from our transcriptome analysis and diet supplementation experiments following decolonisation suggest that bacteria support larval development by contributing to folate biosynthesis and by enhancing energy storage. Our study establishes a tool to study the microbiota in insects and deepens our knowledge on the metabolic contribution of bacteria to mosquito development.
蚊虫微生物群影响宿主的生理机能，对幼虫的正常发育至关重要，从而影响媒介传播病原体。目前采用的无菌方法生成的蚊子显示出幼虫发育不良和发育缺陷。因此，蚊虫微生物群的功能研究迄今为止大多局限于对新出现的成虫进行抗生素处理。在这项研究中，我们介绍了一种生产无菌埃及伊蚊的方法。它基于对经过基因改造的细菌进行可逆定植，以便在任何发育阶段都能完全去定植。我们发现，与以前使用无菌饮食生产的无菌蚊子不同，可逆定植的蚊子没有发育迟缓现象，且与对照组成虫大小相同。这使我们能够将幼虫和成虫中的微生物组研究分开。在成虫中，我们没有发现细菌定植对蚊子繁殖力或寿命有影响。在幼虫中，我们对去定植后转录组分析和饮食补充实验的数据进行分析，结果表明细菌通过参与叶酸生物合成和增强能量储存来支持幼虫发育。我们的研究建立了一种研究昆虫微生物群的工具，并加深了我们对细菌对蚊子发育的代谢贡献的认识。
