Genome reconstructions indicate the partitioning of ecological functions inside a phytoplankton bloom in the Amundsen Sea, Antarctica.
Genome reconstructions indicate the partitioning of ecological functions inside a phytoplankton bloom in the Amundsen Sea, Antarctica.
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DOI：
10.3389/fmicb.2015.01090
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发表时间：
2015
影响因子：
5.2
通讯作者：
Post AF
中科院分区：
文献类型：
--
作者：
Delmont TO;Eren AM;Vineis JH;Post AF
南极冰穴支持浮游植物大量繁殖，通过大量消耗无机碳和营养物质影响其环境。这些水华主要是由菌落形成的附着菌Phaeocystis anaerotica，它们伴随着一个独特的细菌种群。然而，这些细菌可能发挥的生态作用，在P. anastritica水华有待阐明其功能基因库和地球化学活动，他们支持。在这里，我们报告了对阿蒙森海冰穹（南极洲西部）与南极洲P. antarctica水华事件相关的微生物群落的宏基因组（~1.6亿次读取）分析。最丰富的拟杆菌和变形菌种群的基因组已经重建和网络分析表明，这些细菌类群的强大的功能分区。其中三个（SAR92，以及Oceanoacellaceae和Cryomorphaceae的成员）与P. anaerotica菌落密切相关。它们的碳水化合物、氮、硫和铁代谢的独特特征可能有助于支持与P. anastritica的互利关系。SAR92基因组表明，它在将脂肪酸和二甲基磺基丙酸酯（由南极原杆菌释放的化合物）降解为二甲硫醚（一种气溶胶前体）方面具有特化性。海洋硅藻科基因组携带的基因可能会增强藻类生理（钴胺素合成）。最后，冰蕨科基因组富含在细胞或菌落侵入中起作用的基因。还回收了一种新的微微真核生物，微单胞菌相关基因组（19.6 Mb，约94%完整）。它含有一种防冻蛋白质的基因，这是低纬度地区的微单胞菌所缺乏的。这些基因组草图代表了南大洋表面丰富的微生物类群。
Antarctica polynyas support intense phytoplankton blooms, impacting their environment by a substantial depletion of inorganic carbon and nutrients. These blooms are dominated by the colony-forming haptophyte Phaeocystis antarctica and they are accompanied by a distinct bacterial population. Yet, the ecological role these bacteria may play in P. antarctica blooms awaits elucidation of their functional gene pool and of the geochemical activities they support. Here, we report on a metagenome (~160 million reads) analysis of the microbial community associated with a P. antarctica bloom event in the Amundsen Sea polynya (West Antarctica). Genomes of the most abundant Bacteroidetes and Proteobacteria populations have been reconstructed and a network analysis indicates a strong functional partitioning of these bacterial taxa. Three of them (SAR92, and members of the Oceanospirillaceae and Cryomorphaceae) are found in close association with P. antarctica colonies. Distinct features of their carbohydrate, nitrogen, sulfur and iron metabolisms may serve to support mutualistic relationships with P. antarctica. The SAR92 genome indicates a specialization in the degradation of fatty acids and dimethylsulfoniopropionate (compounds released by P. antarctica) into dimethyl sulfide, an aerosol precursor. The Oceanospirillaceae genome carries genes that may enhance algal physiology (cobalamin synthesis). Finally, the Cryomorphaceae genome is enriched in genes that function in cell or colony invasion. A novel pico-eukaryote, Micromonas related genome (19.6 Mb, ~94% completion) was also recovered. It contains the gene for an anti-freeze protein, which is lacking in Micromonas at lower latitudes. These draft genomes are representative for abundant microbial taxa across the Southern Ocean surface.