Rampant Host Switching Shaped the Termite Gut Microbiome
Rampant Host Switching Shaped the Termite Gut Microbiome
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DOI：
10.1016/j.cub.2018.01.035
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发表时间：
2018-02-19
期刊：
影响因子：
9.2
通讯作者：
Evans, Theodore A.
中科院分区：
文献类型：
--
作者：
Bourguignon, Thomas;Lo, Nathan;Evans, Theodore A.
动物的肠道微生物群对宿主生物学产生重大影响[1]。虽然水平转移通常被认为是哺乳动物肠道细菌获得的普遍途径[2]，但一些细菌谱系在数百万年的时间尺度上与其宿主共同形成[3]。白蚁具有复杂的肠道微生物群，它们先进的社会行为为长期垂直共生体传播以及肠道共生体和宿主的共同进化提供了可能[4-6]。尽管白蚁的肠道微生物群有明确的进化模式[7]，但关于白蚁多样化期间微生物群落如何组装的共识尚未达成。尽管一些研究得出结论认为垂直传播发挥了重要作用[8，9]，但其他研究表明饮食和肠道微环境是形成白蚁肠道中微生物群落的主要决定因素[7，10]。为了解决这个问题，我们通过16 S rRNA元条形码检测了94种白蚁的肠道微生物群。我们分析了从白蚁肠道获得的211个细菌谱系的遗传，包括使用BLAST鉴定的来自其他环境的最近亲属。这一结果为肠道细菌在白蚁寄主谱系间的水平传播提供了有力的证据。虽然大多数白蚁衍生的细菌类型形成了大的单系群，表明高水平的生态位专业化，许多其他分支穿插与其他动物的肠道细菌谱系。我们的研究结果表明，“混合模式”传播，即集落到后代的垂直传播与水平集落到集落的转移相结合，一直是形成白蚁肠道微生物群的主要驱动力。
The gut microbiota of animals exert major effects on host biology [1]. Although horizontal transfer is generally considered the prevalent route for the acquisition of gut bacteria in mammals [2], some bacterial lineages have co-speciated with their hosts on timescales of several million years [3]. Termites harbor a complex gut microbiota, and their advanced social behavior provides the potential for long-term vertical symbiont transmission, and co-evolution of gut symbionts and host [4-6]. Despite clear evolutionary patterns in the gut microbiota of termites [7], a consensus on how microbial communities were assembled during termite diversification has yet to be reached. Although some studies have concluded that vertical transmission has played a major role [8, 9], others indicate that diet and gut microenvironment have been the primary determinants shaping microbial communities in termite guts [7, 10]. To address this issue, we examined the gut microbiota of 94 termite species, through 16S rRNA metabarcoding. We analyzed the phylogeny of 211 bacterial lineages obtained from termite guts, including their closest relatives from other environments, which were identified using BLAST. The results provided strong evidence for rampant horizontal transfer of gut bacteria between termite host lineages. Although the majority of termite-derived phylotypes formed large monophyletic groups, indicating high levels of niche specialization, numerous other clades were interspersed with bacterial lineages from the guts of other animals. Our results indicate that "mixed-mode'' transmission, which combines colony-to-offspring vertical transmission with horizontal colony-to-colony transfer, has been the primary driving force shaping the gut microbiota of termites.