Evolutionary conservation in RegulonDB is limited to gammaproteobacteria. Conservation of a regulatory interaction, i.e. a TF regulating a target gene, is inferred from the overrepresentation of TFBSs in upstream regions of the orthologous target genes. We searched for TFBS conservation only in those genomes with an ortholog for the TF and for the regulated gene. Orthologs were selected based on a bidirectional best-hit procedure using RSAT tools package. Overrepresentation is calculated based on the binomial distribution; the binomial significance is shown in following table as significance of conservation.