Nature：实验环境基因组学

环境基因组学使我们对真实世界中微生物的认识发生了革命性变化，但该学科并不是关于微生物在实验室获得的“克隆”培养中的行为的。本期Nature报告了“实验环境基因组学”的一个新颖的例子，涉及创建一个由从美国佐治亚州Sapelo岛附近收集到的海水构成的微型生态环境。对该体系的操纵表明，这个沿海微生物群落被能利用多种有机化合物的代谢性泛食微生物所支配，而不是被专门代谢溶解的有机碳中某一特定成分的细菌菌种所支配。这一发现对于识别碳循环相关过程的分类—功能关系及对于海洋生物地球化学预测模型的构建都具有重要意义。

英文原文：

Nature 451, 708-711 (7 February 2008) | doi:10.1038/nature06513; Received 20 September 2007; Accepted 30 November 2007; Published online 27 January 2008

Bacterial carbon processing by generalist species in the coastal ocean

Xiaozhen Mou1, Shulei Sun1, Robert A. Edwards2, Robert E. Hodson1 & Mary Ann Moran1

Department of Marine Sciences, University of Georgia, Athens, Georgia 30602, USA
Department of Computer Science, San Diego State University, San Diego, California 92182, USA

Correspondence to: Mary Ann Moran1 Correspondence and requests for materials should be addressed to M.A.M. (Email: mmoran@uga.edu).

Abstract

The assimilation and mineralization of dissolved organic carbon (DOC) by marine bacterioplankton is a major process in the ocean carbon cycle1. However, little information exists on the specific metabolic functions of participating bacteria and on whether individual taxa specialize on particular components of the marine DOC pool2. Here we use experimental metagenomics to show that coastal communities are populated by taxa capable of metabolizing a wide variety of organic carbon compounds. Genomic DNA captured from bacterial community subsets metabolizing a single model component of the DOC pool (either dimethylsulphoniopropionate or vanillate) showed substantial overlap in gene composition as well as a diversity of carbon-processing capabilities beyond the selected phenotypes. Our direct measure of niche breadth for bacterial functional assemblages indicates that, in accordance with ecological theory, heterogeneity in the composition and supply of organic carbon to coastal oceans may favour generalist bacteria. In the important interplay between microbial community structure and biogeochemical cycling, coastal heterotrophic communities may be controlled less by transient changes in the carbon reservoir that they process and more by factors such as trophic interactions and physical conditions.