Positive interactions are common among culturable bacteria

Interspecies interactions shape the structure and function of microbial communities. In particular, positive, growth-promoting interactions can substantially affect the diversity and productivity of natural and engineered communities. However, the prevalence of positive interactions and the conditions in which they occur are not well understood. To address this knowledge gap, we used kChip, an ultrahigh-throughput coculture platform, to measure 180,408 interactions among 20 soil bacteria across 40 carbon environments. We find that positive interactions, often described to be rare, occur commonly and primarily as parasitisms between strains that differ in their carbon consumption profiles. Notably, nongrowing strains are almost always promoted by strongly growing strains (85%), suggesting a simple positive interaction-mediated approach for cultivation, microbiome engineering, and microbial consortium design.

Automated summary

The study used an ultrahigh-throughput coculture platform to measure interactions among 20 soil bacteria in 40 carbon environments, finding that positive interactions were prevalent and primarily occurred as parasitisms between strains with differing carbon consumption profiles. In 85% of cases, non-growing strains were promoted by strongly growing strains, suggesting a simple positive interaction-mediated approach for cultivation, microbiome engineering, and microbial consortium design.