Inhibition of Catalase Isozymes of Helicoverpa armigera(Lepidoptera: Noctuidae) by Salicylic acid

The cotton bollworm, Helicoverpa armigera is a polyphagous pest and causes oxidative damage to field crops. Salicylic acid is the cell signaling molecule produced in response to insect attack on plants. Catalase plays a major role in the protection of tissues from the toxic effects of H2O2 and partially reduced oxygen species. Invitroand Invivo effect of salicylic acid was studied on the activities of catalases of Helicoverpa armigera, and tissue distribution of catalase isoforms was also studied. Eight catalase isoforms were found in the gut and whole body preparations whereas single isoforms in the hemolymph. Salicylic acid inhibited over 90 % of catalase activity at 2 mM concentrations in the gel activity staining as well as spectrophotometrically, but catalase I in all the preparations are stable and insensitive to salicylic acid.