Studies on two oxidoreductases and polyphenol oxidase from cowpea infected by Meloidogyne incognita Race 1

The activity of two oxidoreductase enzymes (viz, Malate dehydrogenase and Glucose 6-phosphate dehydrogenase) and the enzyme plyphenol oxidase were studies in cowpea cultivar Pusa Do Fasli at the intervals of 7 and 14 days, following inoculation by the nematode. Meloidogyne incognita race 1. Activity of these enzymes increased when compared to their respective controls following inoculation with the nematode at both the intervals. Polyacrylamide gel electrophoresis (PAGE) analysis of polyphenol oxidase revealed that four new isozynmes were produced in the roots 7 days after inoculation, identical number of isozymes were observed 14 days after inoculation, but their Rb values differed. The shoot samples showed the appearance of two new isozymes at both the intervals, with the disappearance of 3 isozymes in infected plants after 14 days of inoculation. Correspondingly, the phenol concentration also increased with infection. PAGE analysis of MDH. 7 Days after infection revealed the appearance of 2 new isozymes in the roots and one isozyme in the shoot following infection.