What is it about?
Microbes live in complex communities where many species depend on the same limited resources. One major question in ecology is how these organisms avoid direct competition and coexist in environments as different as the ocean, freshwater, soil, and the human gut. In this study, we developed CaCo, a computational approach that uses microbial genomes to estimate which carbon-based resources different microbes are able to use. By comparing these predicted resource-use profiles, CaCo measures how much two microbes overlap in their “food preferences” and therefore how strongly they may compete. We applied this approach to more than 14,000 high-quality microbial genomes from global microbiomes. We found a clear ecological pattern: in low-resource environments such as ocean and freshwater systems, microbes tend to be more specialized and show lower overlap in resource use. In richer environments such as soils and the human gut, microbes tend to have broader resource-use capacities and greater overlap. We also found that closely related microbes tend to share more similar resource-use profiles, suggesting that they may compete more strongly. Importantly, we validated CaCo using laboratory measurements of carbon use and published microbial interaction experiments, showing that genome-based predictions can reflect real ecological interactions.
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Why is it important?
Microbial communities drive essential processes such as nutrient cycling, carbon transformation, ecosystem functioning, and human health. However, predicting how microbes interact has remained difficult, especially across large and complex datasets. This study provides a scalable way to translate genomic data into ecological information about niche overlap and competition. CaCo shows that resource availability shapes microbial competition across major biomes, linking classical ecological theory with modern metagenomics. The framework can be used to generate testable predictions about microbiome assembly, stability, and response to environmental change. This is particularly relevant for understanding how microbial communities may shift under climate change, eutrophication, land-use change, pollution, or changes in host-associated environments such as the gut.
Perspectives
CaCo simplifies complex genomic information into clear ecological metrics that can indicate how microbial communities share or partition resources. These metrics may help reveal important aspects of ecosystem functioning, such as competition, specialization, coexistence, and potential stability. Because microbial interactions influence carbon cycling, nutrient dynamics, and ecosystem responses to disturbance, this approach can be useful for studying how microbiomes respond to environmental change. In the future, CaCo could help monitor ecosystem health and predict how microbial communities may shift under pressures such as climate change, eutrophication, pollution, or changes in resource availability.
HUGO SARMENTO
Universidade Federal de Sao Carlos
Read the Original
This page is a summary of: Resource availability structures microbial competition through genomic niche partitioning, Proceedings of the National Academy of Sciences, April 2026, Proceedings of the National Academy of Sciences,
DOI: 10.1073/pnas.2526391123.
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