Poster: Oxidative stress

Abs # 80: Oxidative Characteristics of Cadmium-Resistant Arabidopsis

Presenter:	Cho, Un-Haing , uhcho@sarim.changwon.ac.kr
Authors	Cho, Un-Haing  (A)   Seo, Nam-Ho  (A)
Affiliations:	(A): Changwon National University

An increasing body of evidence suggests that the metal-induced phytotoxicity can be attributed, at least in part, to oxidative damage. However, little is known about the mechanisms of metal-induced oxidative stress in plants. We selected cadmium (Cd)-resistant type (RT) derived from Arabidopsis thaliana (WT, Colombia) treated with EMS, and the seedlings were grown on MS media containing up to 500 μM CdCl₂, Under these conditions, compared with WT, RT showed higher survival ratio, lower levels of H₂O₂ and lipid peroxidation products and higher activities of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and ascorbate peroxidase (APX), experiencing lower oxidative stress. Further, RT-PCR, RNA blot analyses and gel-activity test of SOD isoforms such as Mn-SOD, Fe-SOD and Cu/Zn-SOD showed higher transcription and enzyme activities of both Mn-SOD and Fe-SOD during Cd exposure in RT. Meanwhile, compared with WT, the transgenic seedlings overexpressing CuZnSOD showed better growth and higher survival on Cd exposure, indicating that SOD could be affected by Cd ion and might be a critical enzyme in Cd-induced oxidative stress. Our results suggest that Cd-induced phytotoxicity is mainly induced by oxidative stress, and Cd tolerance is related to the plant¡¯s ability to quench reactive oxygen species (ROS).