Expression of an aprA′-′lacZ fusion. This reporter carried by pME6060 was measured, in triplicate, in P. fluorescens CHA0 (wild type, open squares), CHA1201 (pycB−, open triangles), and CHA1322 (fumA−, closed triangles). The strains were grown in Erlenmeyer flasks containing NYB. The symbols indicate averages, and the error bars indicate S.D. values. OD600 nm, optical density at 600 nm.