Genomics and host specialization of honey bee and bumble bee gut symbionts
Genomics and host specialization of honey bee and bumble bee gut symbionts
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DOI：
10.1073/pnas.1405838111
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发表时间：
2014-08-05
影响因子：
11.1
通讯作者：
Moran, Nancy A.
中科院分区：
文献类型：
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作者：
Kwong, Waldan K.;Engel, Philipp;Moran, Nancy A.
蜜蜂的优势种是蜜蜂Gilberella apicola和Sassgrassella alvi。和熊蜂（Bombus spp.）肠道微生物群我们获得了G型菌株的完整基因组。apicola wkB 1（T）和S. alvi wkB 2（T）（分离自蜜蜂），以及来自熊蜂的其他四个菌株的基因组草图。G. apicola和S. alvi被发现占据非常不同的代谢生态位：前者是糖分解发酵，而后者是羧酸的氧化剂。它们一起可以形成一个互养网络，用于分配代谢资源。这两个种属都具有许多可能介导细胞-细胞相互作用和肠道定植的基因[6型分泌系统、毒素重复序列（RTX）毒素、RHS蛋白、粘附素和IV型皮利]。这些基因的变异可以解释在以前的系统发育研究中观察到的菌株的宿主保真度。在这里，我们也展示了第一个实验证据，据我们所知，这种特异性在体内：菌株的S。alvi能够殖民他们的本地蜜蜂宿主，但不能殖民另一个属的蜜蜂。与特定的，长期的主机协会一致，比较基因组分析揭示了一个深刻的分歧，很少或根本没有基因流之间的蜜蜂和熊蜂肠道共生体。然而，在宿主类型（蜜蜂或熊蜂）中，我们检测到G. apicola和S. alvi，展示了更广泛的肠道社区在塑造任何一个成员的进化中的重要性。我们的研究结果表明，宿主特异性可能是由多种因素驱动的，包括直接宿主-微生物相互作用，微生物-微生物相互作用和社会传播。
Gilliamella apicola and Snodgrassella alvi are dominant members of the honey bee (Apis spp.) and bumble bee (Bombus spp.) gut microbiota. We generated complete genomes of the type strains G. apicola wkB1(T) and S. alvi wkB2(T) (isolated from Apis), as well as draft genomes for four other strains from Bombus. G. apicola and S. alvi were found to occupy very different metabolic niches: The former is a saccharolytic fermenter, whereas the latter is an oxidizer of carboxylic acids. Together, they may form a syntrophic network for partitioning of metabolic resources. Both species possessed numerous genes [type 6 secretion systems, repeats in toxin (RTX) toxins, RHS proteins, adhesins, and type IV pili] that likely mediate cell-cell interactions and gut colonization. Variation in these genes could account for the host fidelity of strains observed in previous phylogenetic studies. Here, we also show the first experimental evidence, to our knowledge, for this specificity in vivo: Strains of S. alvi were able to colonize their native bee host but not bees of another genus. Consistent with specific, long-term host association, comparative genomic analysis revealed a deep divergence and little or no gene flow between Apis and Bombus gut symbionts. However, within a host type (Apis or Bombus), we detected signs of horizontal gene transfer between G. apicola and S. alvi, demonstrating the importance of the broader gut community in shaping the evolution of any one member. Our results show that host specificity is likely driven by multiple factors, including direct host-microbe interactions, microbe-microbe interactions, and social transmission.