尽管空间和营养都在竞争,细菌物种通常共存于结构化中,表面附着的群落称为生物膜。虽然这些社区发挥了重要作用,在生态系统中的广泛作用,是人类感染的媒介,了解多种细菌物种如何组装形成这些群落,以及支持多物种生物膜组成的物理过程仍然是一个活跃的研究领域。使用由铜绿假单胞菌组成的三物种群落模型,大肠杆菌,和粪肠球菌,我们用细胞尺度分辨率显示了占主导地位的社区成员的分散,铜绿假单胞菌,防止竞争排斥的发生,导致这三种物种共存。铜绿假单胞菌bqsS缺失突变体不再经历周期性的质量扩散,导致大肠杆菌的局部竞争性排斥。介绍定期,将非对称扩散行为转化为最小模型,仅由最大生长速率和局部密度参数化,支持这样一种直觉,即有偏见地分散否则占主导地位的竞争对手通常可以允许共存。定植实验表明,WT铜绿假单胞菌在定植新区域方面具有优势,与ΔbqsS相比,铜绿假单胞菌,但以当地对大肠杆菌和粪肠杆菌的竞争力下降为代价。总的来说,我们的实验记录了一个物种对竞争-分散-殖民权衡的调制如何继续影响空间结构生态系统中多物种共存的稳定性。
Despite competition for both space and nutrients, bacterial species often coexist within structured, surface-attached communities termed biofilms. While these communities play important, widespread roles in ecosystems and are agents of human infection, understanding how multiple bacterial species assemble to form these communities and what physical processes underpin the composition of multispecies biofilms remains an active area of research. Using a model three-species community composed of Pseudomonas aeruginosa, Escherichia coli, and Enterococcus faecalis, we show with cellular-scale resolution that biased dispersal of the dominant community member, P. aeruginosa, prevents competitive exclusion from occurring, leading to the
coexistence of the three species. A P. aeruginosa bqsS deletion mutant no longer undergoes periodic mass dispersal, leading to the local competitive exclusion of E. coli. Introducing periodic, asymmetric dispersal behavior into minimal models, parameterized by only maximal growth rate and local density, supports the intuition that biased dispersal of an otherwise dominant competitor can permit
coexistence generally. Colonization experiments show that WT P. aeruginosa is superior at colonizing new areas, in comparison to ΔbqsS P. aeruginosa, but at the cost of decreased local competitive ability against E. coli and E. faecalis. Overall, our experiments document how one species\' modulation of a competition-dispersal-colonization trade-off can go on to influence the stability of multispecies
coexistence in spatially structured ecosystems.