Department of Evolutionary and Environmental Biology, University of Haifa, Haifa, Israel.
Department of Zoology, Savitribai Phule Pune University, Pune, India; Department of Biology, York University, Toronto, Canada.
Sci Total Environ. 2021 Jun 1;771:145330. doi: 10.1016/j.scitotenv.2021.145330. Epub 2021 Jan 22.
Chironomids are aquatic insects that are known to be pollution tolerant. We have recently demonstrated that endogenous chironomid microbiota protects its host from toxic metals. Following these findings, we hypothesized that under different environmental conditions, a different bacterial consortium will evolve. Our aim was to explore the change in chironomid larval microbiota composition triggered by exposure to toxic copper and hexavalent chromium. Chironomid larvae were collected from the environment and treated in the laboratory with copper, hexavalent chromium, and no metal (control). After six days, the microbial composition of the surviving larvae was examined. We found a significant change in larval microbiota composition between the three treatments and for different copper concentrations. The abundance of specific taxa varied significantly between the treatments. At the genus level, the abundance of some genera (e.g. Yersinia, Acinetobacter) increased in the presence of copper, and some genera (e.g. Yersinia, Dysgonomonas, Delftia, Enterococcus) increased in the presence of hexavalent chromium, compared to the control. The change in the larval microbiota composition was rapid and metal-specific. We suggest that each larva hosts a consortium of bacterial species that can proliferate under a specific environmental change and thus, protect the insect under unstable environmental conditions.
摇蚊是一种水生昆虫，已知对污染具有耐受性。我们最近的研究表明，内源性摇蚊微生物群可以保护其宿主免受有毒金属的侵害。基于这些发现，我们假设在不同的环境条件下，会进化出不同的细菌共生体。我们的目的是探索暴露于有毒铜和六价铬后，摇蚊幼虫微生物组组成的变化。我们从环境中收集摇蚊幼虫，并在实验室中用铜、六价铬和无金属（对照）处理它们。六天后，检查存活幼虫的微生物组成。我们发现三种处理方式和不同铜浓度之间的幼虫微生物组组成有显著变化。处理之间的特定分类群丰度差异显著。在属水平上，与对照相比，一些属（如 Yersinia、Acinetobacter）的丰度在铜存在时增加，而一些属（如 Yersinia、Dysgonomonas、Delftia、Enterococcus）在六价铬存在时增加。幼虫微生物组组成的变化是快速且具有金属特异性的。我们认为，每只幼虫都寄生着一群可以在特定环境变化下增殖的细菌物种，从而在不稳定的环境条件下保护昆虫。
