Differential response of sweetpotato peroxidase to heavy metal stress
Oxidative stress is one of the major causes of damage in plants exposed to different types of environmental stress,including heavy metals. Accumulation of heavy metals in plants can disrupt many cellular functions and plant growth. To assess the contribution of oxidative stress to heavy metal toxicity in plants,young sweetpotato plants (Ipomoea batatas) were treated with increasing concentrations of cadmium (Cd),copper (Cu) and zinc (Zn). Plant growth was significantly inhibited and internal metal content was increased in a dose-dependent manner for each metal. The generation of H-2O-2 in leaves and fibrous roots correlated positively with metal dose. The specific activity of peroxidases (PODs) in fibrous roots was markedly enhanced by metal treatment,whereas in leaves, activity was low and only slightly affected by metal treatment. Analysis of 13 POD genes revealed differential expression of PODs in response to heavy metals. Several genes for acidic PODs (swpa2, swpa3 and swpa 4)and basic PODs (swpb1,swpb3 and swpab4) were strongly expressed under all metal treatment conditions in leaves or fibrous roots. The expression of swpa) was increased in leaves and fibrous roots by Cd and Cu treatment,whereas swpb5 expression was reduced by all metals in fibrous roots. These results indicate that increased H-2O-2 levels in response to heavy metal stress are closely linked to an improved an-tioxidant defense capability mediated by POD.
heavy metal stress oxidative stress peroxidase phytoremediation sweetpotato
KIM Yun-Hee LEE Haeng-Soon KWAK Sang-Soo
Environmental Biotechnology Research Center, Korea Research Institute of Bioscience and Biotechnology,Daejeon 305-806,Korea
国际会议
徐州
英文
305-311
2010-11-27（万方平台首次上网日期，不代表论文的发表时间）