Department of Biology, Microbial Ecology, University of Konstanz, Konstanz, Germany.
Microb Ecol. 2010 Jan;59(1):59-75. doi: 10.1007/s00248-009-9608-7.
Bacteria are very important degraders of organic substances in aquatic environments. Despite their influential role in the carbon (and many other element) cycle(s), the specific genetic identity of active bacteria is mostly unknown, although contributing phylogenetic groups had been investigated. Moreover, the degree to which phenotypic potential (i. e., utilization of environmentally relevant carbon substrates) is related to the genomic identity of bacteria or bacterial groups is unclear. The present study compared the genomic fingerprints of 27 bacterial isolates from the humic River Warnow with their ability to utilize 14 environmentally relevant substrates. Acetate was the only substrate utilized by all bacterial strains. Only 60% of the strains respired glucose, but this substrate always stimulated the highest bacterial activity (respiration and growth). Two isolates, both closely related to the same Pseudomonas sp., also had very similar substrate utilization patterns. However, similar substrate utilization profiles commonly belonged to genetically different strains (e.g., the substrate profile of Janthinobacterium lividum OW6/RT-3 and Flavobacterium sp. OW3/15-5 differed by only three substrates). Substrate consumption was sometimes totally different for genetically related isolates. Thus, the genomic profiles of bacterial strains were not congruent with their different substrate utilization profiles. Additionally, changes in pre-incubation conditions strongly influenced substrate utilization. Therefore, it is problematic to infer substrate utilization and especially microbial dissolved organic matter transformation in aquatic systems from bacterial molecular taxonomy.
细菌是水生环境中有机物质的重要降解者。尽管它们在碳（和许多其他元素）循环中具有重要作用，但活性细菌的特定遗传身份大多未知，尽管已经研究了有贡献的系统发育群。此外，表型潜力（即，利用环境相关的碳基质）与细菌或细菌群的基因组身份的关系尚不清楚。本研究比较了腐殖质河流 Warnow 的 27 个细菌分离物的基因组指纹与其利用 14 种环境相关基质的能力。乙酸盐是所有细菌菌株唯一利用的基质。只有 60%的菌株呼吸葡萄糖，但该基质总是刺激最高的细菌活性（呼吸和生长）。两个分离物，都与同一假单胞菌属密切相关，也具有非常相似的基质利用模式。然而，相似的基质利用图谱通常属于遗传上不同的菌株（例如，Janthinobacterium lividum OW6/RT-3 和黄杆菌属 OW3/15-5 的基质图谱仅相差三种基质）。对于遗传上相关的分离物，有时基质的消耗完全不同。因此，细菌菌株的基因组图谱与其不同的基质利用图谱不一致。此外，预孵育条件的变化强烈影响基质的利用。因此，从细菌分子分类学推断水生系统中基质的利用和特别是微生物溶解有机物质的转化是有问题的。
