Simon Holly M, Jahn Courtney E, Bergerud Luke T, Sliwinski Marek K, Weimer Paul J, Willis David K, Goodman Robert M
Department of Plant Pathology, Gaylord Nelson Institute for Environmental Studies, University of Wisconsin-Madison, Madison, WI 53706, USA.
Appl Environ Microbiol. 2005 Aug;71(8):4751-60. doi: 10.1128/AEM.71.8.4751-4760.2005.
Because archaea are generally associated with extreme environments, detection of nonthermophilic members belonging to the archaeal division Crenarchaeota over the last decade was unexpected; they are surprisingly ubiquitous and abundant in nonextreme marine and terrestrial habitats. Metabolic characterization of these nonthermophilic crenarchaeotes has been impeded by their intractability toward isolation and growth in culture. From studies employing a combination of cultivation and molecular phylogenetic techniques (PCR-single-strand conformation polymorphism, sequence analysis of 16S rRNA genes, fluorescence in situ hybridization, and real-time PCR), we present evidence here that one of the two dominant phylotypes of Crenarchaeota that colonizes the roots of tomato plants grown in soil from a Wisconsin field is selectively enriched in mixed cultures amended with root extract. Clones recovered from enrichment cultures were found to group phylogenetically with sequences from clade C1b.A1. This work corroborates and extends our recent findings, indicating that the diversity of the crenarchaeal soil assemblage is influenced by the rhizosphere and that mesophilic soil crenarchaeotes are found associated with plant roots, and provides the first evidence for growth of nonthermophilic crenarchaeotes in culture.
由于古菌通常与极端环境相关联，因此在过去十年中发现属于泉古菌门的非嗜热成员出乎意料；它们在非极端的海洋和陆地生境中惊人地普遍存在且数量丰富。这些非嗜热泉古菌的代谢特征因其难以在培养中分离和生长而受到阻碍。通过采用培养和分子系统发育技术相结合的研究（PCR-单链构象多态性、16S rRNA基因序列分析、荧光原位杂交和实时PCR），我们在此提供证据表明，在威斯康星州一块田地土壤中生长的番茄植株根系上定殖的泉古菌两个优势系统型之一，在用根提取物改良的混合培养物中被选择性富集。从富集培养物中回收的克隆在系统发育上与C1b.A1分支的序列归为一类。这项工作证实并扩展了我们最近的发现，表明泉古菌土壤群落的多样性受根际影响，且嗜温土壤泉古菌与植物根系相关，并为非嗜热泉古菌在培养中的生长提供了首个证据。
