Heterogeneous composition of key metabolic gene clusters in a vent mussel symbiont population.
Heterogeneous composition of key metabolic gene clusters in a vent mussel symbiont population.
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DOI：
10.1038/ismej.2015.176
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发表时间：
2016-04
期刊：
影响因子：
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通讯作者：
Yoshida T
中科院分区：
文献类型：
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作者：
Ikuta T;Takaki Y;Nagai Y;Shimamura S;Tsuda M;Kawagucci S;Aoki Y;Inoue K;Teruya M;Satou K;Teruya K;Shimoji M;Tamotsu H;Hirano T;Maruyama T;Yoshida T
化学合成共生是适应包括极端环境在内的广泛生境的成功系统之一，而共生体的代谢能力使宿主生物能够扩大其栖息地范围。然而，我们对使共生生物能够扩大其栖息地的适应策略的理解仍然是零散的。在这里，我们报道了在寄主贝类中的单个核糖型内共生菌群体，关于氢氧化和硝酸盐还原的关键代谢基因簇的组成，具有异质性的基因组。寄主个体拥有或不具有编码氢酶或硝酸还原酶基因簇的异质共生体亚群。不同的共生菌亚群在寄主中的比例似乎随着环境或寄主的发育而变化。此外，共生菌亚群在鳃中呈斑块分布，形成镶嵌格局。内共生菌种群中的基因组异质性可能使不同底物的不同利用成为可能，并赋予代谢灵活性。我们的发现开启了我们理解共生生物如何改变其新陈代谢能力和扩大其栖息地范围的新篇章。
Chemosynthetic symbiosis is one of the successful systems for adapting to a wide range of habitats including extreme environments, and the metabolic capabilities of symbionts enable host organisms to expand their habitat ranges. However, our understanding of the adaptive strategies that enable symbiotic organisms to expand their habitats is still fragmentary. Here, we report that a single-ribotype endosymbiont population in an individual of the host vent mussel, Bathymodiolus septemdierum has heterogeneous genomes with regard to the composition of key metabolic gene clusters for hydrogen oxidation and nitrate reduction. The host individual harbours heterogeneous symbiont subpopulations that either possess or lack the gene clusters encoding hydrogenase or nitrate reductase. The proportions of the different symbiont subpopulations in a host appeared to vary with the environment or with the host's development. Furthermore, the symbiont subpopulations were distributed in patches to form a mosaic pattern in the gill. Genomic heterogeneity in an endosymbiont population may enable differential utilization of diverse substrates and confer metabolic flexibility. Our findings open a new chapter in our understanding of how symbiotic organisms alter their metabolic capabilities and expand their range of habitats.