Department of Molecular Ecology, Max Planck Institute for Marine Microbiology, Bremen, Germany.
ISME J. 2012 Oct;6(10):1949-65. doi: 10.1038/ismej.2012.37. Epub 2012 May 3.
Members of the highly diverse Miscellaneous Crenarchaeotal Group (MCG) are globally distributed in various marine and continental habitats. In this study, we applied a polyphasic approach (rRNA slot blot hybridization, quantitative PCR (qPCR) and catalyzed reporter deposition FISH) using newly developed probes and primers for the in situ detection and quantification of MCG crenarchaeota in diverse types of marine sediments and microbial mats. In general, abundance of MCG (cocci, 0.4 μm) relative to other archaea was highest (12-100%) in anoxic, low-energy environments characterized by deeper sulfate depletion and lower microbial respiration rates (P=0.06 for slot blot and P=0.05 for qPCR). When studied in high depth resolution in the White Oak River estuary and Hydrate Ridge methane seeps, changes in MCG abundance relative to total archaea and MCG phylogenetic composition did not correlate with changes in sulfate reduction or methane oxidation with depth. In addition, MCG abundance did not vary significantly (P>0.1) between seep sites (with high rates of methanotrophy) and non-seep sites (with low rates of methanotrophy). This suggests that MCG are likely not methanotrophs. MCG crenarchaeota are highly diverse and contain 17 subgroups, with a range of intragroup similarity of 82 to 94%. This high diversity and widespread distribution in subsurface sediments indicates that this group is globally important in sedimentary processes.
高度多样的混杂古菌群（MCG）成员在各种海洋和大陆生境中分布广泛。在本研究中，我们应用了一种多相方法（rRNA 斑点杂交、定量 PCR（qPCR）和催化报告物沉积 FISH），使用新开发的探针和引物原位检测和定量不同类型海洋沉积物和微生物垫中的 MCG 古菌。一般来说，在缺氧、低能量环境中，MCG（球菌，0.4μm）相对于其他古菌的丰度最高（12-100%），其特征为硫酸盐深度消耗和微生物呼吸速率较低（斑点杂交 P=0.06，qPCR P=0.05）。在白橡河河口和水合物脊甲烷渗漏研究中，以高深度分辨率进行研究时，MCG 丰度相对于总古菌和 MCG 系统发育组成的变化与硫酸盐还原或甲烷氧化随深度的变化无关。此外，MCG 丰度在渗漏点（甲烷营养作用速率高）和非渗漏点（甲烷营养作用速率低）之间没有显著差异（P>0.1）。这表明 MCG 可能不是甲烷营养菌。MCG 古菌群高度多样，包含 17 个亚群，其群内相似性范围为 82%至 94%。这种高多样性和在地下沉积物中的广泛分布表明，该群在沉积过程中具有全球性的重要性。
