Herbivore- and Elicitor- Induced Resistance in Groundnut to Asian armyworm, Spodoptera litura (Fab.) (Lepidoptera: Noctuidae)

Abstract

Induced defense was studied in three groundnut genotypes ICGV 86699 (resistant), NCAc 343 (resistant) and TMV 2 (susceptible) in response to Spodoptera litura infestation and jasmonic acid (JA) application. The activity of the oxidative enzymes [peroxidase (POD) and polyphenol oxidase (PPO)] and the amounts other host plant defense components [total phenols, hydrogen peroxide (H2O2), malondialdehyde (MDA), and protein content] were recorded at 24, 48, 72 and 96 h in JA pretreated (one day before) plants and infested with S. litura, and JA application and simultaneous infestation with S. litura to understand the defense response of groundnut genotypes against S. litura damage. Data on plant damage, larval survival and larval weights were also recorded. There was a rapid increase in the activities of POD and PPO and in the quantities of total phenols, H2O2, MDA and protein content in the JA pretreated + S. litura infested plants. All the three genotypes showed quick response to JA application and S. litura infestation by increasing the defensive compounds. Among all the genotypes, higher induction was recorded in ICGV 86699 in most of the parameters. Reduced plant damage, low larval survival and larval weights were observed in JA pretreated plants. It suggests that pretreatment with elicitors, such as JA could provide more opportunity for plant defense against herbivores.