Genomic context and regulons of genes involved in sugar utilization in representative Shewanella genomes. Panel A contains metabolic pathways discussed in the main text as the "core" and intermediate" subsets. Panel B contains "rare' pathways described in the additional file 4. Genes are colored by their functional classification: sugar transport systems, yellow; cytoplasmic enzymes catalyzing biochemical transformations, blue; transcriptional regulators, black; extracytoplasmic sugar hydrolytic enzymes and auxiliary proteins functionally linked to the pathway, gray. Genes with novel functional roles predicted in this work are outlined in red. For each sugar-specific transcription factor, predicted DNA binding sites are shown by black dots and a consensus DNA-binding motif is shown as a sequence logo.