Piriformospora indica, an excellent system for heavy metal sequestration and amelioration of oxidative stress and DNA damage in Cassia angustifolia Vahl under copper stress.

Present investigation reveals copper induced phytotoxicity, oxidative stress and DNA damage in Cassia angustifolia Vahl and its amelioration by employing a symbiotic fungus, Piriformospora indica. Seeds were germinated on Knop's medium containing five Cu levels (0, 1, 10, 50, 100 and 200 mg L-1), with and without P. indica. Colonization with P. indica significantly (P < 0.05) ameliorated Cu induced oxidative stress. However, maximum amelioration was observed at 50 mg L-1 Cu with P. indica. Atomic absorption spectroscopy revealed that P. indica colonization significantly inhibited Cu accumulation in shoots. Maximum decline in Cu accumulation in shoots was observed at 50 mg L-1 (27.27%) with P. indica over Cu alone. Besides, P. indica colonized seedlings stored 16.86% higher Cu in roots as compared to Cu alone at 200 mg L-1. Similarly, maximum proline accumulation increased up to 19.32% over Cu alone at 50 mg L-1 Cu with P. indica. Significant elevation in antioxidant enzyme levels of superoxide dismutase, catalase, ascorbate peroxidase, guaiacol peroxidase and glutathione reductase was seen with P. indica. Contrary to increase in antioxidant level, toxic parameters such as lipid peroxidation and hydrogen peroxide decreased significantly with P. indica. Maximum decline in lipid peroxidation (13.76%) and hydrogen peroxide (18.58%) was observed at 50 mg L-1 with P. indica over Cu alone. P. indica significantly reduced DNA damage as well as changed the protein profile in C. angustifolia seedlings. Thus, P. indica proved to be an excellent system to alleviate Cu induced oxidative stress and might be useful as a phytostabilization tool.