Department of Microbiology, Oregon State University, Corvallis, Oregon, USA.
Water Quality Engineering, Berlin TU, Berlin, Germany.
Microbiol Mol Biol Rev. 2023 Jun 28;87(2):e0012422. doi: 10.1128/mmbr.00124-22. Epub 2023 Mar 30.
In this review, we consider the regulatory strategies of aquatic oligotrophs, microbial cells that are adapted to thrive under low-nutrient concentrations in oceans, lakes, and other aquatic ecosystems. Many reports have concluded that oligotrophs use less transcriptional regulation than copiotrophic cells, which are adapted to high nutrient concentrations and are far more common subjects for laboratory investigations of regulation. It is theorized that oligotrophs have retained alternate mechanisms of regulation, such as riboswitches, that provide shorter response times and smaller amplitude responses and require fewer cellular resources. We examine the accumulated evidence for distinctive regulatory strategies in oligotrophs. We explore differences in the selective pressures copiotrophs and oligotrophs encounter and ask why, although evolutionary history gives copiotrophs and oligotrophs access to the same regulatory mechanisms, they might exhibit distinctly different patterns in how these mechanisms are used. We discuss the implications of these findings for understanding broad patterns in the evolution of microbial regulatory networks and their relationships to environmental niche and life history strategy. We ask whether these observations, which have emerged from a decade of increased investigation of the cell biology of oligotrophs, might be relevant to recent discoveries of many microbial cell lineages in nature that share with oligotrophs the property of reduced genome size.
在这篇综述中，我们探讨了水生寡营养生物的调控策略，这些微生物细胞适应在海洋、湖泊和其他水生生态系统中的低营养浓度下茁壮成长。许多研究报告得出的结论是，寡营养生物的转录调控比适应该高营养浓度且更常见于实验室调控研究的富营养生物要少。理论上，寡营养生物保留了其他的调控机制，如核糖开关，这些机制提供了更短的响应时间和更小的响应幅度，所需的细胞资源也更少。我们考察了在寡营养生物中存在独特调控策略的累积证据。我们探讨了富营养生物和寡营养生物所面临的选择压力的差异，并提出一个问题，即尽管进化历史赋予了富营养生物和寡营养生物相同的调控机制，但它们在这些机制的使用方式上可能表现出明显不同的模式，原因是什么。我们讨论了这些发现对理解微生物调控网络的进化以及它们与环境生态位和生活史策略的关系的广泛模式的影响。我们还询问了这些观察结果是否与最近在自然界中发现的许多具有与寡营养生物相似的基因组大小减少特征的微生物谱系有关，这些观察结果是从对寡营养生物细胞生物学的十年研究中得出的。
