Activity of defense related enzymes and gene expression in pigeon pea (Cajanus cajan) due to feeding of Helicoverpa armigera larvae

The biochemical and molecular basis of the defense in a mild tolerant (ICPL-332) and susceptible (ICPL-87) cultivars of pigeon pea (Cajanus cajan) due to Helicoverpa. armigera infestation was studied. We found that feeding by the larvae generated H2O2 in a localized manner and activity was observed upto 12 h (hrs) of with a sharp decline within 24 h. Similarly, PPO activity was also detected till 12 h of treatment, which decreased after 24 h of feeding by larvae. The activity of trypsin inhibitor was detected in all the treatments when assayed at 12 and 24 h after larval feeding. The expression of defense genes like the Pre-hevein-like protein PR-4 precursor (PR-4), protease inhibitor/seed storage/LTP family protein (Ltp) were significantly up-regulated in ICPL-332 upon infestation after 12 h as compared to ICPL-87, whereas the endo 1, 4 -β-glucanase (Kor-1) gene was expressed in both the cultivars after 24 h of infestation. Both the cultivars varied with respect to the induction of defense-related genes during larval feeding, both the PR-4 and Ltp genes appeared to be important for defense against H. armigera in pigeon pea. Thus, the present study revealed an insight of herbivore-induced biochemical and molecular changes in pigeon pea