Involvement of superoxide dismutases and superoxide radicals in the susceptibility and resistance of tomato plants to Meloidogyne incognita attack

• Published in: Physiological and molecular plant pathology Vol. 32; no. 2; pp. 313 - 322
• Main Authors: Zacheo, G., Bleve-Zacheo, T.
• Format: Journal Article
• Language: English
• Published: London Elsevier India Pvt Ltd 01.03.1988; Elsevier
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Generalities; Genetics and breeding of economic plants; Pest animals; Pest resistance; Phytopathology. Animal pests. Plant and forest protection; Protozoa. Invertebrates; Records, symptoms, damages, economic importance, population surveys; Varietal selection. Specialized plant breeding, plant breeding aims; Enzyme; Superoxide dismutase; Hyperoxides; Pest; Sensitivity resistance; Meloidogyne incognita; Vegetable crop; Dicotyledones; Angiospermae; Lycopersicon esculentum; Helmintha; Radical anion; Nemathelminthia; Spermatophyta; Solanaceae; Invertebrata; Nematoda; Cultivar
• ISSN: 0885-5765; 1096-1178
• DOI: 10.1016/S0885-5765(88)80026-2

Changes in the reduction of nitroblue tetrazolium (NBT) or cytochrome c and in the activity of superoxide dismutase (SOD) were investigated in the roots of tomato cultivars resistant or susceptible to the root-knot nematode, Meloidogyne incognita Chitw. In the resistant cultivars, nematode infestation stimulated the generation of O − 2 as identified by NBT reduction, and a decrease in SOD activity. In the susceptible cultivars, the response to nematode infestation was a decrease in NBT reduction and an increase in SOD activity. The reduction of NBT or cytochrome c was increased by the presence of NADPH in the reaction medium, and inhibited by the presence of SOD. The reduction of NBT was stimulated when KCN was added to the reaction medium in presence of oxygen. Nematode infestation leads to the production of superoxide anions (O − 2). In susceptible cultivars these are scavenged by the increased SOD activity. In the resistant cultivars the relative inactivity of SOD produced an increase in the superoxide anions; this is considered as a possible cause of cell necrosis and the hypersensitive reaction which is common to many resistant plants.