Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment
Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment
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DOI：
10.1038/ismej.2017.140
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发表时间：
2018-01-01
期刊：
影响因子：
11
通讯作者：
Suzuki, Yohey
中科院分区：
文献类型：
--
作者：
Ino, Kohei;Hernsdorf, Alex W.;Suzuki, Yohey
最近基于单基因的大陆深层含水层调查表明，广泛存在与假丝酵母菌(ANME-2d)有关的古菌，该菌可介导甲烷的厌氧氧化(AOM)。然而，目前尚不清楚ANME-2d是否参与了大陆深层生物圈的AOM。在这项研究中，我们发现在花岗岩中300米深的地下钻孔中，ANME-2d在富含硫酸盐和甲烷的地下水中占主导地位。从地下钻孔中获得的ANME-2d代表种的一个近完整的基因组具有AOM和同化硫酸盐还原所需的大部分功能基因。亚表面的ANME-2d的基因组不同于ANME-2d的其他成员的基因组，因为它缺乏编码硝酸盐和亚硝酸盐还原酶以及多血红素细胞色素的功能基因。此外，ANME-2d亚表面基因组含有一个膜结合的NiFe氢酶基因，该基因可能与呼吸H-2氧化有关，这与其他甲烷营养古生菌不同。从花岗岩地下水中采集的微生物细胞与C-13标记的甲烷的短期培养也表明，AOM与微生物硫酸盐还原有关。鉴于花岗岩陆壳的重要性，以及陆相地下流体中的硫酸盐和甲烷，我们认为AOM可能广泛存在于大陆生物圈深处。
Recent single-gene-based surveys of deep continental aquifers demonstrated the widespread occurrence of archaea related to Candidatus Methanoperedens nitroreducens (ANME-2d) known to mediate anaerobic oxidation of methane (AOM). However, it is unclear whether ANME-2d mediates AOM in the deep continental biosphere. In this study, we found the dominance of ANME-2d in groundwater enriched in sulfate and methane from a 300-m deep underground borehole in granitic rock. A near-complete genome of one representative species of the ANME-2d obtained from the underground borehole has most of functional genes required for AOM and assimilatory sulfate reduction. The genome of the subsurface ANME-2d is different from those of other members of ANME-2d by lacking functional genes encoding nitrate and nitrite reductases and multiheme cytochromes. In addition, the subsurface ANME-2d genome contains a membrane-bound NiFe hydrogenase gene putatively involved in respiratory H-2 oxidation, which is different from those of other methanotrophic archaea. Short-term incubation of microbial cells collected from the granitic groundwater with C-13-labeled methane also demonstrates that AOM is linked to microbial sulfate reduction. Given the prominence of granitic continental crust and sulfate and methane in terrestrial subsurface fluids, we conclude that AOM may be widespread in the deep continental biosphere.