FIG 2 .

The X. campestris pv. campestris ΔnagA mutant is altered in pathogenicity on Arabidopsis thaliana and during growth in xylem sap from cabbage. X. campestris pv. campestris strains (OD₆₀₀ = 0.05) were inoculated onto A. thaliana ecotype Sf-2 leaves by piercing. (A) Disease index scored at 8 dpi (days postinoculation) and presented as a percentage of the value for the wild-type (wt) strain. Standard deviations were obtained from at least 16 inoculated leaves from four plants. Values significantly different (P < 0.0001) from those for the wt strain (a) and the ΔnagA mutant (b) are indicated. (B) Black rot symptoms observed on leaves at 8 dpi. (C) IGC in the inoculated area. Bacteria were extracted from inoculated leaves at different dpi and counted by plating serial dilutions. Results are given as CFU per cm² of leaves. Standard deviations were obtained from at least 3 independent samples. (D) Growth of X. campestris pv. campestris strains in xylem sap from Brassica oleracea cv. Bartolo F1 cabbages (OD₆₀₀ = 0.01 at time zero). At different time points, CFU were counted by plating serial dilutions. Standard deviations were obtained from at least 3 independent experiments.