Modulation of arsenic toxicity-induced oxidative damage by coronatine pretreatment in sweet basil (Ocimum basilicum) seedlings

Abstract

Coronatine (COR), a functional analogue of jasmonates, affects the accumulation of defense-related metabolites in plants. However, information on how its effects may be mediated by heavy metal stress is scanty. This study was carried out to determine the changes in some physiological parameters in sweet basil (Ocimum basilicum L.) seedlings pretreated with COR under arsenic (As) toxicity. COR was applied to seedlings at the three-leaf stage at 50 and 100 nanomolars (nmol·L−1). Arsenic at 150 and 300 μmol·L−1was imposed after completion of COR treatment. Toxic effects of As were reflected by the reduction in growth parameters and photosynthetic pigments and induction of lipid peroxidation coupled with enhancing hydrogen peroxide and electrolyte leakage in leaves. Under As toxicity, plants treated with COR significantly increased the fresh mass and relative water content in leaves. The increase was accompanied by decreased lipid peroxidation and hydrogen peroxide content and maintenance of chlorophyll pigments. COR supplement also increased the accumulation of phenolic compounds and proline content in the leaf of As-treated seedlings. Pretreatment with COR significantly enhanced activities of catalase (CAT), superoxide dismutase (SOD), and guaiacol peroxidase (POD) in basil leaves under As treatment. The results suggested that COR might alleviate As toxicity in sweet basil by activating antioxidant enzymes and inducing conservative components, thereby preventing membrane peroxidation.