Peroxidase activity during susceptible and resistant interactions between cassava (Manihot esculenta) and Xanthomonas axonopodis pv. manihotis and Xanthomonas cassavae

Phenolic compounds have been implicated in the resistance of cassava (Manih ot esculenta) to xanthomonads. Cassava cultivars MCOL 22 and CM 523-7 were inoculated with Xanthomonas axonopodis pv. manihotis and Xanthomonas cassav ae. CM523-7 was susceptible to both pathogens, whereas MCOL 22 was suscepti ble to X. a. pv. manihotis and resistant to X. cassavae. In the resistant i nteraction, no disease symptoms were observed in the leaf, bacterial growth was greatly reduced, and there was a twofold increase in cell wall-bound p eroxidase activity, which may be related to lignin deposition.