Synergistic coevolution in mono-specific and multi-species microbial consortia

• Applicant: Professor Dr. Christian Kost
• Subject Area: Microbial Ecology and Applied Microbiology
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 571482185

Bacteria frequently engage in metabolic cross-feeding interactions, in which they exchange essential nutrients with other members of their local community. Initially, these synergistic interactions rely on an unspecific exchange of metabolic by-products. Over time, however, coevolution among interactors can facilitate the emergence of cooperative interactions, in which strains actively increase the production of the traded metabolite at a cost to themselves. Given that bacteria typically live in taxonomically diverse communities, the questions arises how the possibility to interact with multiple genotypes of the same or a different species simultaneously affects the coevolutionary process. This issue will be addressed using an experimental evolution approach. In detail, a previously performed experiment will be analysed, in which pairs of amino acid auxotrophic genotypes of the same or a different species have been serially cocultivated for 250 bacterial generations. In addition, a second experiment will be performed, in which two, three or four auxotrophic genotypes of different bacterial species will be coevolved with each other. In both cases, derived strains and consortia will be subjected to a series of diagnostic tests to verify whether cooperative cross-feeding evolved and if this was more likely to occur in interactions within or between bacterial species. Invasion experiments and microscopy-based assays will be performed to determine whether a positive fitness feedback within multicellular clusters, which has been previously identified as driving the evolution of cooperation among conspecific auxotrophs, also caused cooperative cross-feeding between species. Finally, it will be tested whether and to which extent the simultaneous presence of different interaction partners affects the strength of synergistic coevolution and, in this way, the degree of partner specificity, phenotypic diversification, and local adaptation. Taken together, the proposed project will provide first experimental insights into the factors that drive the evolution of metabolic interactions in taxonomically diverse microbiomes. The expected results are anticipated to lead to the development of innovative strategies to favour the evolution of rationally designed microbial consortia towards beneficial states.

• DFG Programme: Research Grants