Antioxidant enzymes in Solena amplexicaulis (Lam.) Gandhi plants against Aulacophora foveicollis lucas

Abstract

We investigated the induced defensive responses in Solena amplexicaulis (Lam.) Gandhi (Cucurbitaceae) plants caused by feeding of Aulacophora foveicollis (Lucas) (Coleoptera: Chrysomelidae) adults at different time intervals. The activity of defensive enzymes [catalase (CAT), superoxide dismutase (SOD), peroxidases towards phenolic substances {pyrogallol (PPX), syringaldazine (SPX) and guaiacol (GPX)}, ascorbate peroxidase (APOX) and glutathione reductase (GR)], hydrogen peroxide (H2O2), total phenols, thiols and proteins were recorded in undamaged plants and in plants 6, 12 and 24 h after A. foveicollis feeding. Induction of enzyme activities (CAT, SOD, PPX, SPX, GPX APOX and GR) and the phenols content were higher in plants 24 h after insect feeding than plants 6 h after insect feeding. While the total amounts of H2O2, proteins and thiols were higher in plants 6 h after insect feeding followed by plants 12 and 24 h after insect feeding. The results suggested that differential induction of CAT, SOD, peroxidases to phenolic substances and APOX rapidly reduced the H2O2 content in insect damaged plants. The increase in activity of these enzymes matched their function to control the accumulation of H2O2 and detoxify this reactive oxygen product, when S. amplexicaulis plants were fed on A. foveicollis.