Oxidative burst reaction in homologous C. annuum suspension cell cultures after elicitation with OGAs of a DP exceeding 8. A fraction of isolated OGAs, which had a DP of at least 8, was able to elicit a strong oxidative burst reaction in heterologous N. tabacum suspension cell cultures (Figure 10). Now this OGA fraction was tested in homologous C. annuum suspension cell cultures. Samples were added to the C. annuum culture to a final concentration of 5 mg/ml (○). A negative control contained only water (♦). Once more this OGA fraction evoked a strong oxidative burst, similar to the reaction in N. tabacum. These observations show that OGAs with a DP of at least 8 that were generated by an X. campestris pv. campestris culture from co-incubated C. annuum cell wall material are a powerful endogenous elicitor.