Physiological changes in groundnut plants induced by pathogenic infection of Cercosporidium personatum Deighton

We studied the role of defence-related enzymes induced in groundnut plants due to pathogen infection by Cercosporidium personatum. The enzymatic changes in three groundnut varieties exposed to leaf spot disease by artificial inoculation technique in greenhouse were estimated using spectrophotometric analysis. Involvement of defence related enzymes in leaf spot pathogenesis was studied in susceptible (ICG 221) and tolerant (ICGV 86590, ICG FDRS 10) groundnut varieties. Temporal accumulation of peroxidase, phenyl alanine ammonia lyase and lipoxygenase enzymes showed maximum activity after pathogen inoculation in tolerant varieties, whereas in susceptible cultivars, there was no significant change between the pathogen free and pathogen infected variety. Tolerant varieties showed higher enzymatic activity after pathogen inoculation than normal (un-inoculated) plants and also the susceptible variety. The glucanase activity was increased in ICG 221 and ICG FDRS 10 and decreased in ICGV 86590 A. hypogaea plants. Furthermore, there was a significant increase in the phenolic content in all three varieties and a decrease in the catalase activity. The role of these defence-related enzymes induced in A. hypogaea due to pathogen infection is discussed.