Vertical segregation and phylogenetic characterization of ammonia-oxidizing Archaea in a deep oligotrophic lake
Vertical segregation and phylogenetic characterization of ammonia-oxidizing Archaea in a deep oligotrophic lake
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DOI：
10.1038/ismej.2012.33
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发表时间：
2012-09-01
期刊：
影响因子：
11
通讯作者：
Casamayor, Emilio O.
中科院分区：
文献类型：
--
作者：
Auguet, Jean-Christophe;Triado-Margarit, Xavier;Casamayor, Emilio O.
淡水生境已被确定为古细菌遗传多样性的最大储存库之一，具有不同于土壤和海洋的氨氧化古细菌（AOA）种群的特定谱系。然而，湖泊AOA的生态学和生物学却鲜为人知。本研究通过CARD-FISH、qPCR和克隆文库鉴定古细菌丰度的垂直变化与深冰川高海拔雷东湖环境参数的相关性。该湖位于西班牙比利牛斯山脉中部，那里的大气沉积物是活性氮的主要来源。古细菌16S rRNA基因丰度和古细菌amoA基因丰度与亚硝酸盐浓度呈强相关，表明这些微生物具有氨氧化潜能。未检出细菌amoA基因。沿着垂直梯度揭示了三个具有潜在氨氧化活性的深度，(i)冬春季在湖的顶部（即覆盖冰盖以上的0摄氏度的泥层），（ii）在温跃层和（iii）夏秋季在底部水域。总体而言，高达90%的16S rRNA基因序列与Thaumarchaeota相匹配，主要来自海洋群（MG） 1.1a（亚硝基古菌样）和姐妹分支SAGMGC - 1（亚硝基古菌样）。克隆文库分析显示，与MG 1.1a相比，SAGMGC - 1的相对丰度呈现出水面高、深度低的变化趋势，反映了垂直的系统发育分离。总体而言，SAGMGC - 1的相对丰度和反复出现表明该分支在高寒湖泊中具有重要的环境作用。这些结果扩展了古细菌分布的生态和热条件，揭示了水柱中的垂直定位是了解湖泊环境中不同古细菌分支生态学的关键因素。ISME学报（2012）6,1786-1797；doi: 10.1038 / ismej.2012.33;主题分类：微生物生态学与自然栖息地功能多样性
Freshwater habitats have been identified as one of the largest reservoirs of archaeal genetic diversity, with specific lineages of ammonia-oxidizing archaea (AOA) populations different from soils and seas. The ecology and biology of lacustrine AOA is, however, poorly known. In the present study, vertical changes in archaeal abundance by CARD-FISH, quantitative PCR (qPCR) analyses and identity by clone libraries were correlated with environmental parameters in the deep glacial high-altitude Lake Redon. The lake is located in the central Spanish Pyrenees where atmospheric depositions are the main source of reactive nitrogen. Strong correlations were found between abundance of thaumarchaeotal 16S rRNA gene, archaeal amoA gene and nitrite concentrations, indicating an ammonium oxidation potential by these microorganisms. The bacterial amoA gene was not detected. Three depths with potential ammonia-oxidation activity were unveiled along the vertical gradient, (i) on the top of the lake in winter-spring (that is, the 0 degrees C slush layers above the ice-covered sheet), (ii) at the thermocline and (iii) the bottom waters in summer-autumn. Overall, up to 90% of the 16S rRNA gene sequences matched Thaumarchaeota, mostly from both the Marine Group (MG) 1.1a (Nitrosoarchaeum-like) and the sister clade SAGMGC - 1 (Nitrosotalea-like). Clone-libraries analysis showed the two clades changed their relative abundances with water depth being higher in surface and lower in depth for SAGMGC - 1 than for MG 1.1a, reflecting a vertical phylogenetic segregation. Overall, the relative abundance and recurrent appearance of SAGMGC - 1 suggests a significant environmental role of this clade in alpine lakes. These results expand the set of ecological and thermal conditions where Thaumarchaeota are distributed, unveiling vertical positioning in the water column as a key factor to understand the ecology of different thaumarchaeotal clades in lacustrine environments. The ISME Journal (2012) 6, 1786-1797; doi:10.1038/ismej.2012.33; published online 12 April 2012 Subject Category: microbial ecology and functional diversity of natural habitats