Methanogenic archaea are globally ubiquitous in aerated soils and become active under wet anoxic conditions
Methanogenic archaea are globally ubiquitous in aerated soils and become active under wet anoxic conditions
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DOI：
10.1038/ismej.2011.141
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发表时间：
2012-04-01
期刊：
影响因子：
11
通讯作者：
Conrad, Ralf
中科院分区：
文献类型：
--
作者：
Angel, Roey;Claus, Peter;Conrad, Ralf
产甲烷菌是宽古菌的典型代表，它们对氧敏感，被认为只在高度还原的缺氧环境中出现。然而，我们发现甲烷八叠球菌属和甲烷杆菌属的产甲烷菌存在于全球采样的许多类型高地土壤（包括旱地土壤）中。这些产甲烷菌可以通过在缺氧条件下将土壤培养成泥浆而容易地活化，如在几周内快速产生甲烷所示，而无需任何额外的碳源。通过末端限制性片段长度多态性和定量PCR定量分析的古细菌16 S核糖体RNA基因群落分布在孵育的样品中表明占主导地位的甲烷八叠球菌，其基因拷贝数也与甲烷生产率。对甲烷的δ C-13的分析进一步支持了这一点，因为在大多数情况下，主要的产甲烷途径是乙酸脱氢酶，而甲烷杆菌不能执行。从培养前的土壤样品中检索到的关键产甲烷酶甲基辅酶M还原酶的序列证实甲烷八叠球菌和甲烷杆菌是优势产甲烷菌，尽管也检测到一些甲烷短杆菌和甲烷杆菌的序列。全球只有两个活跃的产甲烷古菌的发生支持的假设，这些是本土成员的高地土壤生物群落，并很好地适应他们的环境。The ISME Journal（2012）6，847-862; doi：10.1038/ismej.2011.141; 2011年11月10日在线发表
The prototypical representatives of the Euryarchaeota-the methanogens-are oxygen sensitive and are thought to occur only in highly reduced, anoxic environments. However, we found methanogens of the genera Methanosarcina and Methanocella to be present in many types of upland soils (including dryland soils) sampled globally. These methanogens could be readily activated by incubating the soils as slurry under anoxic conditions, as seen by rapid methane production within a few weeks, without any additional carbon source. Analysis of the archaeal 16S ribosomal RNA gene community profile in the incubated samples through terminal restriction fragment length polymorphism and quantification through quantitative PCR indicated dominance of Methanosarcina, whose gene copy numbers also correlated with methane production rates. Analysis of the delta C-13 of the methane further supported this, as the dominant methanogenic pathway was in most cases aceticlastic, which Methanocella cannot perform. Sequences of the key methanogenic enzyme methyl coenzyme M reductase retrieved from the soil samples before incubation confirmed that Methanosarcina and Methanocella are the dominant methanogens, though some sequences of Methanobrevibacter and Methanobacterium were also detected. The global occurrence of only two active methanogenic archaea supports the hypothesis that these are autochthonous members of the upland soil biome and are well adapted to their environment. The ISME Journal (2012) 6, 847-862; doi: 10.1038/ismej.2011.141; published online 10 November 2011