Laboratoire MAPIEM, Université de Toulon, CS 60584, Toulon, France.
INRA - Université Savoie Mont-Blanc, UMR CARRTEL, Thonon-les-Bains, France.
Appl Environ Microbiol. 2019 Mar 6;85(6). doi: 10.1128/AEM.02494-18. Print 2019 Mar 15.
Microbes drive a variety of ecosystem processes and services, but many of them remain largely unexplored because of a lack of knowledge on both the diversity and functionality of some potentially crucial microbiological compartments. This is the case with and within the group of bacterial predators collectively known as and like organisms (BALOs). Here, we report the abundance, distribution, and diversity of three families of these obligate predatory Gram-negative bacteria in three perialpine lakes (Lakes Annecy, Bourget, and Geneva). The study was conducted at different depths (near-surface versus 45 or 50 m) from August 2015 to January 2016. Using PCR-denaturing gradient gel electrophoresis (PCR-DGGE) and cloning-sequencing approaches, we show that the diversity of BALOs is relatively low and very specific to freshwaters or even the lakes themselves. While the family was represented mainly by a single species (), it could represent up to 7% of the total bacterial cell abundances. Comparatively, the abundances of the two other families ( and ) were significantly lower. In addition, the distributions in the water column were very different between the three groups, suggesting various life strategies/niches, as follows: dominated near the surface, while and were more abundant at greater depths. Statistical analyses revealed that BALOs seem mainly to be driven by depth and temperature. Finally, this original study was also the opportunity to design new quantitative PCR (qPCR) primers for quantification. This study highlights the abundance, distribution, and diversity of a poorly known microbial compartment in natural aquatic ecosystems, the and like organisms (BALOs). These obligate bacterial predators of other bacteria may have an important functional role. This study shows the relative quantitative importance of the three main families of this group, with the design of a new primer pair, and their diversity. While both the diversity and the abundances of these BALOs were globally low, it is noteworthy that the abundance of the could reach important values.
微生物驱动着各种生态系统过程和服务，但由于对一些潜在关键微生物区室的多样性和功能缺乏了解，其中许多仍然在很大程度上未被探索。这就是被统称为 和类似生物体 (BALO) 的细菌捕食者群体的情况。在这里，我们报告了这三种专性捕食革兰氏阴性细菌在三个高山湖泊（安纳西湖、布尔热湖和日内瓦湖）中的丰度、分布和多样性。该研究于 2015 年 8 月至 2016 年 1 月在不同深度（近表面与 45 或 50 m）进行。使用 PCR-变性梯度凝胶电泳 (PCR-DGGE) 和克隆测序方法，我们表明 BALO 的多样性相对较低，并且非常特定于淡水，甚至是湖泊本身。虽然 家族主要由单一物种（）代表，但它可能代表了总细菌细胞丰度的 7%。相比之下，另外两个家族（和）的丰度要低得多。此外，在水柱中的分布在三组之间差异非常大，表明存在不同的生活策略/小生境，如下所示：在近表面占主导地位，而 和 在更深的地方更丰富。统计分析表明，BALO 似乎主要受深度和温度驱动。最后，这项原始研究也是设计用于 定量的新定量 PCR(qPCR) 引物的机会。本研究强调了自然水生生态系统中一个鲜为人知的微生物区室，即 和类似生物体 (BALO) 的丰度、分布和多样性。这些专性捕食其他细菌的细菌捕食者可能具有重要的功能作用。本研究展示了该组三个主要家族的相对定量重要性，设计了一对新的引物，并对其多样性进行了研究。尽管这些 BALO 的多样性和丰度总体较低，但值得注意的是，的丰度可能达到重要值。
