Fig. 3

Purine metabolism in Aeromonas. A Purine metabolic pathway in 34mel, showing de novo formation of purines (blue arrows) and salvage reactions (green arrows). Enzymes absent in 34mel with the corresponding E.C. numbers are shown with crossed out arrows. B Comparison of the genomic region containing guaD and xdhABC in A. hydrophila showing their absence in representative Aeromonas. Homologous flanking genes are shown: auxin efflux carrier family transporter (green) and ExeM/NucH family extracellular endonuclease (blue) along with the locus tags in each genome. C Phylogenomic tree of Aeromonas species showing the presence (black) or the absence (blue) of the gene encoding the guanine deaminase. The numbers below branches are GBDP pseudo-bootstrap support values > 60% from 100 replications, with an average branch support of 94.4%. The tree was rooted at the midpoint [29]. The strains used and the accession numbers of their genomes are indicated in Additional file 4: Table S3