Induced systemic resistance in chickpea against ascochyta blight by safe chemicals

Chickpea variety, C727 susceptible to Ascochyta rabiei, was grown in small plots of 20 sq feet area. Induction treatments were given by spraying aqueous solutions of 1.0 mM Salicylic acid, 50 mM K2HPO4 (analytical and commercial grade), 0.4 mM Bion and two types of neem leaves extract (50mg/ml, leaves boiled in methanol, methanol was evaporated then residue dissolved in water and in other extract neem leaves were boiled in water) at flowering stage of the plants in triplicates. Control plants were treated with water only. One week after induction treatments, all the plants were challenged with spore suspension of A. rabiei (106 spores/ml). Disease data was recorded after disease was fully developed on control plants. Plant tissues were collected at 0, 24, 48 and 72 hours after induction and challenge treatments for biochemical analyses of proteins and peroxidase enzyme activity as the part of defense mechanism. Blight disease was significantly reduced in chickpea variety C727 after spraying the plants with all the chemicals tested. Maximum reduction in the disease was obtained with Salicylic acid, followed by Bion. Slight increase in yield was observed in Bion, K2HPO4 (commercial) and neem extract treated plants as compared to control plants but the difference was non-significant. Plant tissues collected at different time intervals from induced and control plants after induction and challenged treatments were subjected to biochemical analyses of total proteins, SDS-PAGE, activity of peroxidase enzyme and Native PAGE for isozymes of peroxidase. A significant increase in total proteins and peroxidase activity was observed after induction treatments with all the chemicals tested. However, electrophoresis indicated that pattern of proteins and isoforms of peroxidase were similar in induced and control plants