Heme Oxygenase-1 is Involved in the Modulatory Role of Salicylic Acid in Cadmium-Induced Oxidative Stress in Medicago Sativa
|School||Nanjing Agricultural College|
|Course||Biochemistry and Molecular Biology|
|Keywords||cadmium salicylic acid heme oxygenase-1 oxidative stress Medicago sativa|
Heme oxygenase (HO, EC 18.104.22.168) has been regarded as a rate-limiting enzyme in heme degradation. Recently, it was also found that HO exhibited important functions and HO-1 was regarded as the important antioxidative enzyme in planta. In this study, pretreatment of different concentrations of salicylic acid (SA) was able to alleviate cadmium-induced oxidative damage in the roots of Medicago sativa in a dose-dependent manner, and 10μmol/L SA exhibited the best response, which was consistent with the changes of lipoxygenase (LOX) total and isozyme activity, and corresponding transcripts. Furthermore, the application of 20μmol/L HO-1 inducer hemin displayed the strong antioxidative behavior in comparison with the action of 10μmol/L SA. Meanwhile,100μmol/L ZnPPIX, the potent inhibitor of HO-1, was able to block SA-or hemin-induced the mitigation of oxidative stress in the roots of Medicago sativa conferred by 50μmol/L Cd2+, which was confirmed by TBARS content, histochemical staining with Schiff s reagent and Evans blue. Additionally, the up-regulation of HO-1 transcirpt and its protein as well as HO activity was induced by the addition of different doses of SA, and ZnPPⅨpretreatment reversed the modulation of superoxide dismutase (SOD), guaiacol peroxidase (POD) and ascorbate peroxidase (APX) total and isozyme activities, or their related transcripts caused by 10μmol/L SA. Together, above results suggested that HO-1 might be involved in the modulatory role of SA in cadmium-induced oxidative stress in Medicago sativa.