~ 2596 ~ International Journal of Chemical Studies 2020; 8(1): 2596-2601 P-ISSN: 2349–8528 E-ISSN: 2321–4902 IJCS 2020; 8(1): 2596-2601 © 2020 IJCS Received: 01-11-2019 Accepted: 03-12-2019 Anita Kumari Department of Plant Pathology, Bihar Agricultural University, Sabour, Bihar, India Abhijeet Ghatak Department of Plant Pathology, Bihar Agricultural University, Sabour, Bihar, India Srinivasaraghavan A Department of Plant Pathology, Bihar Agricultural University, Sabour, Bihar, India Corresponding Author: Anita Kumari Department of Plant Pathology, Bihar Agricultural University, Sabour, Bihar, India Biochemical responses of soil-borne necrotroph Sclerotium rolfsii during the pathogenesis on chickpea Anita Kumari, Abhijeet Ghatak and Srinivasaraghavan A DOI: https://doi.org/10.22271/chemi.2020.v8.i1an.8661 Abstract Southern blight caused by Sclerotium rolfsii is a fast spreading and destructive disease of chickpea yield. This disease cause severe damage to plant on almost all growth stage. In our study we have selected two genotype of chickpea i.e one is resistant genotype (GNG1958) and another susceptible genotype (L550) and two isolates of S. rolfsii i.e., highly aggressive (C4) and least aggressive (L9). Both isolates were inoculated on both genotypes and observation of enzymatic activity was done. Peroxidase activity was highest in case of susceptible genotype inoculated with least aggressive isolate. There was depletion in catalase and ascorbate peroxidase activity and enhancement in activity of peroxidase whether it was inoculated with highly or least aggressive isolate, but there was variation in superoxide dismutase activity. The enhanced biochemical activities during plant pathogen interaction triggers the defense related enzymes such as wall-bound phenolics, flavonoids and induction of hypersensitive reaction (HR) etc., which resulted in cell strengthening and enhances resistance to pathogen. The depletion of catalase and ascorbate peroxidase during host-parasite interaction might be due to induction of antioxidant enzyme in plant which leads to oxidative stress and multiplication of pathogen. In case of superoxide dismutase activity when resistant genotype inoculated with least aggressive isolate there was increase in activity but when susceptible genotype inoculated with least aggressive isolate there was decline in superoxide dismutase activity. Which shows superoxide dismutase activity could improve superoxide scavenging system of cells and favor accumulation of superoxide which mainly contributes in damaging the concentration and damage to cell membrane. Keywords: Peroxidase, ascorbate peroxidase, superoxide dismutase, catalase, Sclerotium rolfsii, chickpea Introduction Southern blight caused by the soilborne necrotrophic pathogen, Sclerotium rolfsii is one of the most important devastating soil-borne diseases of chickpea (Cicer arietinum) infecting usually the collar region of the plant. S. rolfsii survives on dead plant material in the soil by forming sclerotia which later germinate and attack young plants, causing necrosis by attacking the cell walls. The pathogen infects all portions of the plant in contact with the soil, and sclerotia that are produced can remain viable for many years and provide the primary inoculum for epidemics. It also produces oxalic acid, which in synergistic action with enzymes causes injury to plant tissue (Aycock, 1961, 1966) [4, 5] . S. rolfsii induces the production of reactive oxygen species (ROS) including superoxide radical, hydrogen peroxide and hydroxyl radical which may results in membrane damage and the destruction of cellular organelles and biomolecules i.e., cause cell death due to oxidative stress such as membrane lipid peroxidation which is reflected by increased malondialdehyde (MDA) concentration, enzyme inhibition and damage to nucleic acids. To repair the S. rolfsii induced inhibitory effects of ROS, plants possess the antioxidative enzymes superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) and peroxidase (POD) (Kanazawa et al., 2000) [14] . In oxidative stress, ROS scavengers and antioxidant enzymes are highly activated to neutralize the negative effect. The fungal inoculation also enhanced the activity of ROS scavenging enzymes CAT, POD, SOD and APX which advocated the presence of high oxidative stress during fungal infection. Similar findings on other hosts under different pathogens stress have been reported (Anthony et al., 2017) [2] .