Lawrence Berkeley National Laboratory

A major goal of the Environmental Stress Pathway Project (ESPP) is to uncover the mechanisms that allow microbes to sustain activity under the environmental stress seen in field settings. In this study, we used 13C isotopomer analysis to elucidate the metabolic flux through central metabolism of eight Shewanella species. Metabolite fluxes link genes, proteins and metabolites to macroscopic biological functions. In spite of its importance, only a few, not thoroughly tested, general principles have been proposed to predict and understand the flux configuration of an organism. Among those general principles, robustness of central metabolism has been reported with respect to genetic perturbation. Here we show that the relative metabolic flux distributions are very similar for phylogenetically and environmentally diverse members of the Shewanella genus. This phylogenetic robustness suggests understanding microbial fluxomics in terms of metabolic types (or metabotypes), as opposed to phylotypes. In addition to phylogenetic, environmental and genetic robustness our data shows flexibility in the relative flux profiles when adapting to different carbon sources.