Département de Biologie, Institut de Biologie Intégrative et des Systèmes (IBIS), Université Laval, 1030, Avenue de la Médecine, Québec, Québec, G1V 0A6, Canada.
Microbiome. 2018 Mar 14;6(1):47. doi: 10.1186/s40168-018-0427-2.
It is well established that symbionts have considerable impact on their host, yet the investigation of the possible role of the holobiont in the host's speciation process is still in its infancy. In this study, we compared the intestinal microbiota among five sympatric pairs of dwarf (limnetic) and normal (benthic) lake whitefish Coregonus clupeaformis representing a continuum in the early stage of ecological speciation. We sequenced the 16s rRNA gene V3-V4 regions of the intestinal microbiota present in a total of 108 wild sympatric dwarf and normal whitefish as well as the water bacterial community from five lakes to (i) test for differences between the whitefish intestinal microbiota and the water bacterial community and (ii) test for parallelism in the intestinal microbiota of dwarf and normal whitefish.
The water bacterial community was distinct from the intestinal microbiota, indicating that intestinal microbiota did not reflect the environment, but rather the intrinsic properties of the host microbiota. Our results revealed a strong influence of the host (dwarf or normal) on the intestinal microbiota with pronounced conservation of the core intestinal microbiota (mean ~ 44% of shared genera). However, no clear evidence for parallelism was observed, whereby non-parallel differences between dwarf and normal whitefish were observed in three of the lakes while similar taxonomic composition was observed for the two other species pairs.
This absence of parallelism across dwarf vs. normal whitefish microbiota highlighted the complexity of the holobiont and suggests that the direction of selection could be different between the host and its microbiota.
共生体对其宿主有很大的影响，这一点已经得到了充分的证实，但对共生体在宿主物种形成过程中可能发挥的作用的研究仍处于起步阶段。在这项研究中，我们比较了 5 对共生的矮（浮游）和正常（底栖）湖白鲑（Coregonus clupeaformis）肠道微生物群，这些白鲑代表了生态物种形成早期的连续体。我们对总共 108 只野生共生矮白鲑和正常白鲑的肠道微生物群的 16s rRNA 基因 V3-V4 区以及来自五个湖泊的水细菌群落进行了测序，以检验：(i) 白鲑肠道微生物群与水细菌群落之间的差异；(ii) 矮白鲑和正常白鲑肠道微生物群之间的平行性。
水细菌群落与肠道微生物群不同，表明肠道微生物群并不反映环境，而是反映了宿主微生物群的内在特性。我们的研究结果表明，宿主（矮或正常）对肠道微生物群有很强的影响，核心肠道微生物群（平均约 44%的共有属）有明显的保守性。然而，没有明显的平行性证据，在三个湖泊中观察到矮白鲑和正常白鲑之间的非平行差异，而在另外两个种对中观察到相似的分类组成。
这种矮白鲑和正常白鲑之间的肠道微生物群没有平行性，突出了共生体的复杂性，并表明宿主与其微生物群之间的选择方向可能不同。
