BIOCHEMICAL AND HISTOPATHOLOGICAL CHANGES IN CHICKPEA (CICER ARIETINUM L.) DURING PATHOGENESIS OF COLLAR ROT FUNGI (SCLEROTIUM ROLFSII SACC)

Abstract

Sclerotium rolfsii (Sacc.), causing collar rot (CR) of chickpea is one of the most perilous soil-borne pathogens that parasitize chickpea at a very early stage, therefore, leading to huge yield loss. The present experiment aimed to study the relative changes in defence-related enzymes and phenolics which take place in chickpea (both in resistant and susceptible genotypes) upon CR infection. Emphasis was given to study the changes in total soluble proteins, peroxidase and total phenol content at 7, 14, and 21-days post inoculation (dpi). The experiment was set up by taking moderately resistant (MR), moderately susceptible (MS), susceptible (S) and highly susceptible (HS) genotypes and the experiment was conducted under both inoculated and non-inoculated conditions. The results indicated that total phenol content was signicantly higher (3 folds) at 7dpi and then declined gradually upto 21dpi. MR cultivars had higher phenol content than the (MS) and the susceptible non-inoculated control. Total soluble protein content decreased with the days after post-inoculation and this reduction is greater in the susceptible cultivar as compared to the MR cultivars. Total soluble protein content was 3 times higher in the inoculated cultivars than in the in-inoculated control. Peroxidase (POD) activity was also decreased from 7dpi to 21dpi and maximum POD activity was recorded at 7dpi in MR cultivars (12.61 g-1 fresh wt.) than the susceptible one (1.31 g-1 fresh wt.). Scanning electron microscopy (SEM) was also done to compare the extent of the mycelial network within the xylem vessels of inoculated MR, MS and susceptible cultivars.