Physical map of the reductive dehalogenase ( rdh ) operons in D. hafniense DCB-2. The catalytic RDase subunit genes, rdhA1 through rdhA7, are colored black, and the docking protein genes, rdhB1 through rdhB7, are colored yellow. Other RDase accessory genes are colored green. Disruptions of rdhA2 and rdhA7 by an insertion of a transposase gene (tra) and by nonsense mutation, respectively, are indicated. The RDase genes, for which transcription was detected by microarrays are indicated with arrows and substrate names with fold induction. All the substrates indicated above the rdhA2, rdhA3, and rdhA6 genes induced their corresponding gene expression in northern hybridization experiments. 3Cl-4OH-BA; 3-chloro-4-hydroxybenzoate, o-BP; ortho-bromophenol, 3,5-DCP; 3,5-dichlorophenol.