FIG 1 .

Accumulation of spontaneous Gac⁻ mutants of Pseudomonas spp. in NYB cultures. (A) Four strains, P. protegens Pf-5, P. fluorescens SS101, P. aeruginosa PAO1, and P. chlororaphis 30-84, were grown independently in NYB for 6 days, and dilutions of cultures were spread on LMA to assess exoprotease production. The percentage of the Gac⁻ mutants in the bacterial population was estimated from counts of exoprotease-deficient colonies relative to total colonies on LMA. At least 400 colonies were screened for each strain. The results of two experiments are shown. (B) Total cell density of the four strains in NYB cultures at 6 dpi. For both panels A and B, results are from two independent experiments (experiment 1 [Exp 1] and Exp 2). Each experiment had at least three replicates. Means ± standard deviations (error bars) are shown.