Indu Ravi and Vinay Sharma
The ROS formation is associated with increased activity of enzymes participating in their metabolism with the induction of defense response in the host moth bean [Vigna aconitifolia (Jacq.) Marechal] plant against the fungal pathogen, Macrophomina phaseolina. Changes in peroxidase (EC 1.11.1.7) activity were determined in control and fungal pathogen inoculated plants of two varieties viz. RMO-40 and FMM-96. The peroxidase activity was higher in the pathogen inoculated plants as compared to control. Varietal differences were also observed as the peroxidase activity was comparatively higher in variety FMM-96, which is moderately resistant as compared to RMO-40 a susceptible variety. The presence of H2O2, which is involved in the oxidative cross-linking of cell wall glycoproteins was also detected histochemically in leaves of moth bean plants as reddish brown patches using 3,3-diaminobenzidine (DAB). The data indicate hydrogen peroxide production and a distinct role of peroxidase in the defense response of moth bean plants, an economically important crop of semi arid regions.