一个新的古菌类群———奇古菌门(Thaumarchaeota)

A novel archaeal phylum: Thaumarchaeota—A review

摘要:

摘要: 基于16S rRNA 基因的系统发育关系，古菌域( Archaea ) 被分为两个主要类群: 广古菌门(Euryarchaeota) 和泉古菌门(Crenarchaeota)。近20 年来，微生物分子生态学技术的快速发展和应用显示，在中温环境中广泛存在着大量的未培养古菌，而且它们可能在自然界重要元素(N、C) 的生物地球化学循环中发挥着重要作用。最初，这些未培养古菌因在16S rRNA 基因系统发育上与泉古菌关系较密切而被称作中温泉古菌( non-thermophilic Crenarchaeota)。而近年来，对更多新发现的中温古菌核糖体RNA 基因序列和其它分子标记物进行的分析均不支持中温泉古菌由嗜热泉古菌进化而来的假设，而揭示其可能代表古菌域中一个独立的系统发育分支。基因组学、生理生态特征等分析也显示中温泉古菌与泉古菌具有明显不同的特征。因而专家建议将这些古菌( 中温泉古菌) 划分为一个新的门，成为古菌域的第三个主要类群—Thaumarchaeota( 意译为奇古菌门)。这一新古菌门提出后得到其他研究证据的支持和认可。本文对目前已知的奇古菌门的分类地位演化、基因组学、多样性和生理代谢特征等作一简要综述。

Abstract:

Abstract:Based on the archaeal 16S rRNA gene phylogenetic tree，the archaeal domain is divided into two major phyla，Euryarchaeota and Crenarchaeota． During the past 20 years，diverse groups of archaea have been found to be widely distributed in moderate environments with the rapid development and application of molecular techniques in microbial ecology． Increasing evidence demonstrated that these archaea，especially ammonia-oxidizing archaea，play a major role in biogeochemical cycles of nitrogen and carbon elements． These mesophilic archaea were placed initially as a sister group of the Crenarchaeota and named as“non-thermophilic Crenarchaeota”．More recently，phylogenetic analyses based on more SSU and SLU rDNA sequences suggested that the non-thermophilic Crenarchaeota constituted a separate phylum of the Archaea that branched off before the separation of Crenarchaeota and Euryarchaeota． The Thaumarchaeota (the Greek “Thaumas”，meaning wonder) was therefore proposed for a novel phylum，as the third archaeal phylum． More studies based on r-proteins and comparative genomics confirm that the Thaumarchaeota are distinct from Crenarchaeota． In this paper，we gave a translated Chinese name for Thaumarchaeota and reviewed the recent progress on the phylogeny position，genetics，ecology and physiology of the Thaumarchaeota．