人类肠道微生物组中 VI 型分泌系统的全景揭示了其在群落组成中的作用。
The Landscape of Type VI Secretion across Human Gut Microbiomes Reveals Its Role in Community Composition.
机构信息
Department of Genome Sciences, University of Washington, Seattle, WA 98195, USA.
Department of Microbiology, School of Medicine, University of Washington, Seattle, WA 98195, USA.
出版信息
Cell Host Microbe. 2017 Sep 13;22(3):411-419.e4. doi: 10.1016/j.chom.2017.08.010.
Although gut microbiome composition is well defined, the mechanisms underlying community assembly remain poorly understood. Bacteroidales possess three genetic architectures (GA1-3) of the type VI secretion system (T6SS), an effector delivery pathway that mediates interbacterial competition. Here we define the distribution and role of GA1-3 in the human gut using metagenomic analysis. We find that adult microbiomes harbor limited effector and cognate immunity genes, suggesting selection for compatibility at the species (GA1 and GA2) and strain (GA3) levels. Bacteroides fragilis GA3 is known to mediate potent inter-strain competition, and we observe GA3 enrichment among strains colonizing infant microbiomes, suggesting competition early in life. Additionally, GA3 is associated with increased Bacteroides abundance, indicating that this system confers an advantage in Bacteroides-rich ecosystems. Collectively, these analyses uncover the prevalence of T6SS-dependent competition and reveal its potential role in shaping human gut microbial composition.
虽然肠道微生物群落的组成已经得到很好的定义，但群落组装的机制仍知之甚少。拟杆菌门拥有三种类型六型分泌系统（T6SS）的遗传结构（GA1-3），这是一种效应器传递途径，介导细菌间的竞争。在这里，我们使用宏基因组分析来定义 GA1-3 在人类肠道中的分布和作用。我们发现成人微生物组中含有有限的效应器和同源免疫基因，这表明在物种（GA1 和 GA2）和菌株（GA3）水平上存在相容性选择。已知脆弱拟杆菌 GA3 介导强烈的菌株间竞争，我们观察到 GA3 在定植于婴儿微生物组的菌株中富集，这表明在生命早期就存在竞争。此外，GA3 与拟杆菌属丰度的增加有关，表明该系统在富含拟杆菌的生态系统中具有优势。总的来说，这些分析揭示了 T6SS 依赖性竞争的普遍性，并揭示了其在塑造人类肠道微生物组成中的潜在作用。
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