The oil quality and yield of groundnut (
L.) is mainly lessened by
Speg. For screening large number of genotypes to rust resistance under
conditions, the present study was motivated to test and verify the reliability of certain pathogen related enzymes, alterations in protein expression level and isoenzymes, activated ahead of host pathogen interaction. Biparental segregants acquired through NCD 1 mating fashion from crosses, viz. TMV1×ICG1697 and VRI2×ICG1697 were artificially inoculated with rust pathogen. After rust infection in groundnut, the alterations in the activity of peroxidase (PO), polyphenol oxidase (PPO), ascorbic acid oxidase (AAO) and chitinase were studied at 80 and 90 days after sowing (DAS) both in susceptible and resistant segregants along with parents. Both susceptible and resistant segregants manifest increased activity of all of these three enzymes, the magnitude was higher in resistant segregants. The activity of ascorbic acid oxidase and chitinase were high at 90 DAS, while polyphenol oxidase and peroxidase exhibited maximum activity at 80 DAS. Four additional isoforms of PO and PPO and prominent expression of a 56 kDa protein were observed in resistant genotypes. The potential amount and activity of these enzymes were genetically determined and such changes in the quantity, isoenzyme and protein can be relied for screening rust tolerant genotypes in groundnut.