Visualization of subpopulations by flow cytometry analysis. P. putida wild-type (A), colR-deficient (B), ttgC-deficient (C) and colRttgC double mutant (D) strains, grown for 24 h on glucose minimal plates supplemented with 3 mM phenol were stained using red fluorescence dye propidium iodide (PI) and green fluorescence dye SYTO9, which both stain nucleic acids. Each dot represents an event, analysed by flow cytometer, that has been exicated at 488 nm and respective fluorescence emission has been measured at 530 (30) and 616 (23) nm. Area of seven different subpopulations is indicated. Density plot of results is presented where lighter areas indicated more events with same parameters.