Department of Biology, University of Konstanz, Universitätsstrasse 10, 78457, Konstanz, Germany.
Current address: Division of Biological Sciences, Section of Ecology, Behavior, & Evolution, University of California San Diego, La Jolla, California, USA.
Microbiome. 2020 Oct 29;8(1):149. doi: 10.1186/s40168-020-00897-8.
Recent increases in understanding the ecological and evolutionary roles of microbial communities have underscored the importance of their hosts' biology. Yet, little is known about gut microbiota dynamics during the early stages of ecological diversification and speciation. We sequenced the V4 region of the 16s rRNA gene to study the gut microbiota of Nicaraguan Midas cichlid fish (Amphilophus cf. citrinellus). Specifically, we tested the hypothesis that parallel divergence in trophic ecology in extremely young adaptive radiations from two crater lakes is associated with parallel changes of their gut microbiota.
Bacterial communities of fish guts and lake water were highly distinct, indicating that the gut microbiota is shaped by host-specific factors. Among individuals of the same crater lake, differentiation in trophic ecology was weakly associated with gut microbiota differentiation, suggesting that diet, to some extent, affects the gut microbiota. However, differences in trophic ecology were much more pronounced across than within species whereas similar patterns were not observed for taxonomic and functional differences of the gut microbiota. Across the two crater lakes, we could not detect conclusive evidence for parallel changes of the gut microbiota associated with trophic ecology.
A lack of clearly differentiated niches during the early stages of ecological diversification might result in non-parallel changes of gut microbial communities, as observed in our study system as well as in other recently diverged fish species. Video Abstract.
近年来，人们对微生物群落的生态和进化作用的理解不断加深，突显了宿主生物学的重要性。然而，人们对生态多样化和物种形成早期阶段肠道微生物群落的动态变化知之甚少。我们对尼加拉瓜 Midas 慈鲷鱼（Amphilophus cf. citrinellus）的 16s rRNA 基因 V4 区进行了测序，以研究其肠道微生物群。具体来说，我们检验了这样一个假设，即在两个火山口湖中极其年轻的适应性辐射中，营养生态的平行分化与它们肠道微生物群的平行变化有关。
鱼肠和湖水的细菌群落高度不同，表明肠道微生物群是由宿主特异性因素塑造的。在同一火山口湖的个体中，营养生态的分化与肠道微生物群的分化呈弱相关，表明饮食在某种程度上影响了肠道微生物群。然而，在物种之间，营养生态的差异要比在物种内部大得多，而在肠道微生物群的分类和功能差异方面则没有观察到类似的模式。在这两个火山口湖中，我们没有发现与营养生态相关的肠道微生物群平行变化的明确证据。
在生态多样化的早期阶段，缺乏明显分化的生态位可能导致肠道微生物群落的非平行变化，正如我们的研究系统以及其他最近分化的鱼类物种所观察到的那样。
