Fig 3.

GacA enhances biofilm formation and decreases soil dissemination. (A) The impact of GacA on biofilm formation was assessed on borosilicate glass by the staining method described by O'Toole and Kolter (21). Biofilm data are reported as the average of 8 to 12 replicates. (B) The motility of Pf0-1 and Pf0-gacA⁺ was assessed in soil microcosms. Radial dissemination from a central inoculation point was measured daily over a 5-day time course. A nonflagellated mutant lacking ΔAdnA is known to have a defect in dissemination in the soil environment (14) and was thus used as a negative control. Results are the average of four to six independent microcosms for each strain tested, with duplicate samples taken at each time point as an internal replicate.