Metabolic changes in enzyme levels in potato roots infested by potato cyst nematodes, Globodera pallida (Pa3) and Globodera rostochiensis (Ro1)

Abstract

Changes in peroxidase, polyphenoloxidase, ascorbic acid oxidase, superoxide dismutase and production of superoxides were investigated in potato roots resistant and susceptible to Globodera rostochiensis pathotype Ro1 and G. pallida pathotype Pa3. Peroxidase activities increased in the soluble fraction of the resistant cv and in the microsomal fraction of the susceptible cv. The activities of polyphenoloxidase and ascorbic acid oxidase were less affected by nematode infestation. The susceptible cv showed a decrease in NBT and cytochrome c reduction and an increase of superoxide dismutase activity. In the resistant cv the nematode infestation elicited the generation of O2 and a decrease in SOD activity. It is postulated that a novel O2 generating system may be activated in infected resistant cv because of the decreased activity of SOD.