SOME BIOCHEMICAL PROPERTIES OF PISUM SATIVUM SUSCEPTIBLE AND RESISTANT TO HETERODERA GOETTINGIANA
AbstractBiochemical changes in roots of a germplasm pea accession resistant to Heterodera goettingiana were compared with those which occur in roots of a susceptible variety. Increased lipid peroxidation of the host cell membranes was induced by nematode infestation of resistant roots. The increase of lipid peroxidation is believed to be initiated by an O[sub2](-.) generating system (NADPH oxidase) present in the membrane of plant tissue and activated in the resistant accession, but not in the susceptible variety. The lack of O[sub2](-.) activation in susceptible infected tissue may result from the protective activity of enzymes such as superoxide dismutase and catalase. The protective activity of these enzymes was enhanced in susceptible but decreased in resistant plants. The resistant tissue was also associated with increased peroxidase activity. This peroxidase activity can be influenced by catalase destroying the H[sub2]O[sub2] substrate. Different isozymes were detected in the peroxidase profiles of resistant and susceptible pea plants. An interpretation of these results is proposed in terms of biochemical characterization of pea plants resistant and susceptible to the cyst nematode, H. goettingiana.