Department of Ecology, Evolution, and Behavior, University of Minnesota, St. Paul, MN, USA.
BioTechnology Institute, University of Minnesota, St. Paul, MN, USA.
Nat Commun. 2021 Jan 27;12(1):619. doi: 10.1038/s41467-021-20922-0.
Although mutualisms are often studied as simple pairwise interactions, they typically involve complex networks of interacting species. How multiple mutualistic partners that provide the same service and compete for resources are maintained in mutualistic networks is an open question. We use a model bacterial community in which multiple 'partner strains' of Escherichia coli compete for a carbon source and exchange resources with a 'shared mutualist' strain of Salmonella enterica. In laboratory experiments, competing E. coli strains readily coexist in the presence of S. enterica, despite differences in their competitive abilities. We use ecological modeling to demonstrate that a shared mutualist can create temporary resource niche partitioning by limiting growth rates, even if yield is set by a resource external to a mutualism. This mechanism can extend to maintain multiple competing partner species. Our results improve our understanding of complex mutualistic communities and aid efforts to design stable microbial communities.
尽管互利共生通常被视为简单的两两相互作用，但它们通常涉及到相互作用的物种的复杂网络。在互利共生网络中，如何维持提供相同服务并争夺资源的多个互利共生伙伴是一个悬而未决的问题。我们使用一种模型细菌群落，其中多个“伙伴菌株”的大肠杆菌竞争碳源，并与沙门氏菌enterica 的“共享共生体”菌株交换资源。在实验室实验中，尽管竞争大肠杆菌菌株的竞争能力存在差异，但在存在沙门氏菌的情况下，它们很容易共存。我们使用生态建模来证明，即使共生关系以外的资源决定了产量，共享共生体也可以通过限制生长速度来暂时划分资源生态位，即使共生关系以外的资源决定了产量。这种机制可以扩展到维持多个竞争的伙伴物种。我们的研究结果提高了我们对复杂互利共生群落的理解，并有助于设计稳定的微生物群落。
