Speaker
Description
The enormous diversity of heterotrophic bacteria in the environment begs the question to what degree their metabolic niches can be understood in terms of a small number of simplified metabolic categories. Here, we show that, despite high variability at all levels of taxonomy, the catabolic niches of heterotrophic bacteria can be understood in terms of their preference for either glycolytic (sugars) or gluconeogenic (amino and organic acids) carbon sources. This preference is encoded in the total number of genes found in pathways that feed into the two modes of carbon utilization and predictable with a simple linear model based on gene counts, allowing for coarse-grained descriptions of microbial communities in terms of prevalent modes of carbon catabolism. The sugar-acid preference is also associated with genomic GC content, and thus with the carbon-nitrogen requirements of their encoded proteome. Our work thus reveals that how the evolution of bacterial genomes is structured by fundamental constraints rooted in metabolism.
