Physics of Living Systems, Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, USA.
Mol Syst Biol. 2022 May;18(5):e10630. doi: 10.15252/msb.202110630.
How the coexistence of species is affected by the presence of multiple resources is a major question in microbial ecology. We experimentally demonstrate that differences in diauxic lags, which occur as species deplete their own environments and adapt their metabolisms, allow slow-growing microbes to stably coexist with faster-growing species in multi-resource environments despite being excluded in single-resource environments. In our focal example, an Acinetobacter species (Aci2) competitively excludes Pseudomonas aurantiaca (Pa) on alanine and on glutamate. However, they coexist on the combination of both resources. Experiments reveal that Aci2 grows faster but Pa has shorter diauxic lags. We establish a tradeoff between Aci2's fast growth and Pa's short lags as their mechanism for coexistence. We model this tradeoff to accurately predict how environmental changes affect community composition. We extend our work by surveying a large set of competitions and observe coexistence nearly four times as frequently when the slow-grower is the fast-switcher. Our work illustrates a simple mechanism, based entirely on supplied-resource growth dynamics, for the emergence of multi-resource coexistence.
物种共存如何受到多种资源存在的影响，这是微生物生态学中的一个主要问题。我们通过实验证明，由于物种耗尽自身环境并适应新陈代谢而导致的双相迟滞差异，使得生长缓慢的微生物能够在多资源环境中与生长更快的物种稳定共存，尽管它们在单资源环境中被排斥。在我们的重点示例中，一种不动杆菌物种（Aci2）在丙氨酸和谷氨酸上对铜绿假单胞菌（Pa）具有竞争性排斥性。然而，它们在两种资源的组合上共存。实验表明，Aci2 生长更快，但 Pa 的双相迟滞更短。我们确定了 Aci2 的快速生长和 Pa 的短迟滞之间的权衡，这是它们共存的机制。我们建立了一个模型来准确预测环境变化如何影响群落组成。我们通过调查一大组竞争来扩展我们的工作，并且当慢生长者是快速转换者时，观察到共存的情况几乎增加了四倍。我们的工作说明了一种简单的机制，这种机制完全基于供应资源的生长动态，是多资源共存出现的原因。
