Figure 2. Cell population density-dependent β-galactosidase expression of a pltA’-‘lacZ translational fusion (pME9524) in P. fluorescens strains CHA0 (wild-type; open squares), CHA0/pME6001 (vector control; filled squares), CHA0/pME6073 (= pME6001 overexpressing rsmA; filled triangles), CHA0/pME6851 (= pME6001 overexpressing rsmE; filled circles) and CHA89 (gacA::Kmr; open circles). Each value is the average from three different cultures ± standard deviation. In some instances, the standard deviation bars are smaller than the symbols used.