Biochemical and Enzymatic Response of Cajanus cajan Plant Towards the Biotic Stress Induced by Fusarium oxysporum udum

Pigeon pea (Cajanus cajan (L) Millsp) is one of the major grain legume crops of the tropics and subtropics, but biotic stresses (Fusarium wilt) of pigeon pea is a major threat for the sustainable crop production. An incompatible interaction between the host and the pathogen results in resistance whereas a compatible interaction leads to the establishment of disease. Infection of a plant by a pathogen initiates changes in the structural, physiological and molecular level. Seven cultivars of Cajanus cajan were screened to differentiate the cultivars as resistant and susceptible. Of the seven, ICPL 87119 was found to be a resistant variety and T 1515 was found to be susceptible on the basis of disease severity index. At the physiological level changes in the biochemical parameters in both the varieties (control as well as inoculated) were observed. Due to infection total soluble proteins, chlorophyll content and phenolics were found to be comparatively higher in the resistant variety than the susceptible variety. Assays of different defence related enzymes such as Peroxidase, Catalase, Phenylalanine ammonia lyase, -1,3 glucanase and Pectin methyl esterase revealed lower activity in the susceptible variety in comparision to resistant variety.