FIG. 3.
Stress sensitivity of ΔrpoE mutants. (A) Influence of cadmium on growth of X. campestris pv. campestris WT and mutant strains containing control plasmid p917 or σE-overexpressing plasmid p917-rpoE. Serial 10-fold dilutions of late-exponential-phase bacteria were spotted on MOKA plates containing 40 μM cadmium and incubated at 30°C for 72 h. Each experiment was repeated three times. (B) Effect of rpoE deletion on stationary-phase survival of X. campestris pv. campestris. Overnight cultures in MOKA medium were diluted to an OD600 of 0.05 (time zero), and survival was monitored by viable-cell counting 24 h (light-gray bars), 48 h (dark-gray bars), and 96 h (black bars) postinoculation. The data are the mean values from four experiments, with the error bars representing standard deviations. The asterisks indicate no detectable cells.