Figure 5.

Hydrogen peroxide formation in C. annuum cell suspension cultures upon elicitation with supernatant of an X. campestris pv. campestris exbD2 mutant co-incubated with cell wall material. To assess the role of the exbD2 gene in provoking defense reactions in non-host plants, cultures of the X. campestris pv. campestris mutant strain B100-11.03 were co-incubated with cell wall material from C. annuum. Then the formation of H₂O₂ was monitored in cell suspension cultures of C. annuum upon the addition either supernatants of X. campestris pv. campestris wild-type cultures (●), supernatants of X. campestris pv. campestris cultures affected in exbD2 that were co-incubated with C. annuum cell wall material (♦), invertase as a positive control (■), or C. annuum cell wall material employed as negative control (✶). The mutated bacterial mutant strain deficient in exbD2 could not evoke an oxidative burst reaction.