Xanthomonas campestris: (A) wild type Xcc 8004; (B) B5 (EPS deficient) (C) B12EPS deficient); (D) ndvB (glucan deficient); and (E) ndvB(pHM1J)+ (complementing strain); cells were treated in the presence or absence of either FeSO4, H2O2 or FeSO4+Dp (dipyridyl) were analyzed for ROS by monitoring DCF fluorescence with flow cytometry. 