Methanogens in the Antarctic Dry Valley permafrost
Methanogens in the Antarctic Dry Valley permafrost
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南极干谷永久冻土层中的产甲烷菌
DOI：
10.1093/femsec/fiy109
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发表时间：
2018
影响因子：
4.2
通讯作者：
Rivkina, Elizaveta M
中科院分区：
文献类型：
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作者：
Vishnivetskaya, Tatiana A;Buongiorno, Joy;Bird, Jordan;Krivushin, Kirill;Spirina, Elena V;Oshurkova, Victoria;Shcherbakova, Victoria A;Wilson, Gary;Lloyd, Karen G;Rivkina, Elizaveta M
极地永久冻土处于气候变化的最前沿，但只有少数研究丰富了可能对气候变化提供积极反馈的天然产甲烷微生物。样品Ant 1和Ant 2，收集在南极迈尔斯谷永久冻土沉积物，有和没有生物甲烷，分别进行了评价产甲烷活性和存在的产甲烷菌。在厌氧条件下对两种样品进行一年的孵育后，仅在室温下观察到微宇宙Ant 1中以CO2/H2（20/80）作为碳源和能源的甲烷产生，并在随后的10年中进行监测。微宇宙Ant 1的顶部空间中的甲烷浓度从0.8%变化到最大45%。微宇宙Ant 1的16 SrRNA基因与耐冷型湖泊甲烷八叠球菌（Methanosarcina lacustris）相关。为获得这种微生物的纯培养物而进行的多次努力都没有成功。将从产甲烷微宇宙Ant 1获得的宏基因组读数进行组装，得到99.84%的完整基因组，属于甲烷八叠球菌属。宏基因组组装的基因组含有冷适应酶和途径，表明新的未培养的甲烷藻。Ant 1适用于永久冻土中的亚冻结条件。这是第一个产甲烷菌基因组报告的15000年前的南极干旱山谷的永久冻土。
Polar permafrost is at the forefront of climate change, yet only a few studies have enriched the native methane-producing microbes that might provide positive feedbacks to climate change. Samples Ant1 and Ant2, collected in Antarctic Miers Valley from permafrost sediments, with and without biogenic methane, respectively, were evaluated for methanogenic activity and presence of methanogens. After a one-year incubation of both samples under anaerobic conditions, methane production was observed only at room temperature in microcosm Ant1 with CO2/H2(20/80) as carbon and energy sources and was monitored during the subsequent 10 years. The concentration of methane in the headspace of microcosm Ant1 changed from 0.8% to a maximum of 45%. Archaeal 16S rRNA genes from microcosm Ant1 were related to psychrotolerantMethanosarcina lacustris. Repeated efforts at achieving a pure culture of this organism were unsuccessful. Metagenomic reads obtained for the methane-producing microcosm Ant1 were assembled and resulted in a 99.84% complete genome affiliated with the genusMethanosarcina. The metagenome assembled genome contained cold-adapted enzymes and pathways suggesting that the novel unculturedMethanosarcinasp. Ant1 is adapted to sub-freezing conditions in permafrost. This is the first methanogen genome reported from the 15 000 years old permafrost of the Antarctic Dry Valleys.