Purification of trypsin inhibitor from seeds of Cicer arietinum (L.) and its insecticidal potential against Helicoverpa armigera (Hübner)

Abstract

Trypsin inhibitors (TI) have crucial functions in plant defense against pests, and recent studies reveal their diversity in stress response. Disease and herbivore infestations are harmful to plant growth, but the response of TI in Cicer arietinum (L.) in Central India has been less studied. In the present study, we partially characterized the TI from Cicer arietinum (L.) seeds and evaluated its insecticidal potential against Helicoverpa armigera (Hübner). A 20 kDa trypsin inhibitor was purified to homogeneity by ammonium sulfate precipitation and chromatographies with Sephadex G-100 and diethylaminoethyl cellulose (DEAE-cellulose-52) ion-exchange column. TI assay categorized 17 cultivars in three groups: with high (more than 70%), intermediate (16–70%) and very low (0–15%) TI activity. Moreover, results from the TI activity coincided with herbivore attack studies carried out in J.N.K.V.V. fields earlier. Together, our results suggest that the presence of TI triggers a signal that leads the dynamics of stress response and, in turn, regulates pest resistance in plants. Feeding experiments conducted with 5th instar larvae suggested dose-dependent decrease for both the larval weight and the survival of the larva.