Figure 5. DM4 requires clcA overexpression to grow on DCM.
(A) The environmental DCM-degrading isolates, DM4 and DM17, overexpress clcA relative to three other strains of M. extorquens (one tailed Welch's t-test with two degrees of freedom). Error bars show ±1 standard deviation, calculated from three biological replicates. (B) Growth on DCM in DM4 and PA1 depends on the clcA promoter but not the strain background. A 140-bp region upstream of clcA (the ‘clcA promoter’) was swapped between PA1 and DM4. Regardless of the genetic background, strains with the DM4 clcA promoter overexpressed clcA and were more fit on DCM compared to strains with the PA1 clcA promoter. All strains expressed dcmA from plasmid pJM10. Error bars show ±1 standard deviation, calculated from three biological replicates.