Changes in Antioxidative Enzymes in Resistant and Susceptible Genotypes of Tomato Infected with Root-Knot Nematode (Meloidogyne incognita)

Changes in activities of antioxidative enzymes (Catalase, Peroxidase, Superoxide dismutase, Polyphenol oxidase, esterase, monodehydro ascorbate reductase, and dehydro ascorbate reductase) after nematode inoculation were investigated in four varieties of tomatoes, (two resistant i.e. Hisar Lalit, PNR- 7 and two susceptible i.e. Punjab Varkha Bahar-1 and Punjab Varkha Bahar-2. These four varieties were infected at the nursery stage with root-knot nematode (Meloidogyne incognita). The egg masses of M. incognita were taken from the infected brinjal plants. Tomato roots and leaves from un-inoculated and inoculated plants were evaluated for their antioxidative enzyme activities after 7 days and 20 days of infection. The activity of antioxidant enzymes increased after infection with root-knot nematode in the resistant varieties of tomato as compared to that of susceptible varieties. The activities of all enzymes increased after inoculation except the activity of CAT enzyme where a decrease was observed. The isozyme banding patterns of peroxidase and esterase showed that the intensity of bands was more in the resistant genotypes as compared to that of susceptible genotypes, which means that the activity of antioxidant enzymes were more after inoculation in the resistant genotypes as compared to that of susceptible genotypes. An additional band was obtained in the isozyme banding pattern of esterase in the resistant genotypes.