Productivity‐poor oligotrophic environments are plentiful on earth. Yet it is not well understood how organisms maintain population sizes under these extreme conditions. Most scenarios consider the adaptation of a single microorganism (isogenic) at the cellular level, which increases their fitness in such an environment. However, in oligotrophic environments, the adaptation of microorganisms at population level – that is, the ability of living cells to differentiate into subtypes with specialized attributes leading to the coexistence of different phenotypes in isogenic populations – remains a little‐explored area of microbiology research. In this study, we performed experiments to demonstrate that an isogenic population differentiated to two subpopulations under low energy‐flux in chemostats. Fluorescence cytometry and turnover rates revealed that these subpopulations differ in their nucleic acid content and metabolic activity. A mechanistic modelling framework for the dynamic adaptation of microorganisms with the consideration of their ability to switch between different phenotypes was experimentally calibrated and validated. Simulation of hypothetical scenarios suggests that responsive diversification upon a change in energy availability offers a competitive advantage over homogenous adaptation for maintaining viability and metabolic activity with time.

中文翻译：

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表型异质性是贫营养条件下生长和存活的关键因素。

贫瘠的贫营养环境在地球上非常丰富。然而，人们还不太了解生物如何在这些极端条件下维持种群规模。大多数方案都考虑了单个微生物在细胞水平上的适应性（同基因），这增加了它们在这种环境中的适应性。但是，在贫营养环境中，微生物在种群水平上的适应性（即，活细胞分化为具有特殊属性的亚型的能力，导致同基因种群中不同表型并存的能力）仍是微生物学研究领域中尚待研究的领域。在这项研究中，我们进行了实验，以证明在等温线的低能量通量下，同基因群体可分化为两个亚种群。荧光细胞计数和周转率表明，这些亚群的核酸含量和代谢活性不同。考虑到微生物在不同表型之间切换的能力，对微生物进行动态适应的机制建模框架已通过实验进行了校准和验证。假设情景的模拟表明，随着能源利用率的变化，响应性多样化与同质适应相比具有竞争优势，可以随时间保持活力和代谢活性。