Haem oxygenase-1 is involved in salicylic acid-induced alleviation of oxidative stress due to cadmium stress in Medicago sativa.
This work examines the involvement of haem oxygenase-1 (HO-1) in salicylic acid (SA)-induced alleviation of oxidative stress as a result of cadmium (Cd) stress in alfalfa (Medicago sativa L.) seedling roots. CdCl(2) exposure caused severe growth inhibition and Cd accumulation, which were potentiated by pre-treatment with zinc protoporphyrin (ZnPPIX), a potent HO-1 inhibitor. Pre-treatment of plants with the HO-1 inducer haemin or SA, both of which could induce MsHO1 gene expression, significantly reduced the inhibition of growth and Cd accumulation. The alleviation effects were also evidenced by a decreased content of thiobarbituric acid-reactive substances (TBARS). The antioxidant behaviour was confirmed by histochemical staining for the detection of lipid peroxidation and the loss of plasma membrane integrity. Furthermore, haemin and SA pre-treatment modulated the activities of ascorbate peroxidase (APX), superoxide dismutase (SOD), and guaiacol peroxidase (POD), or their corresponding transcripts. Significant enhancement of the ratios of reduced/oxidized homoglutathione (hGSH), ascorbic acid (ASA)/dehydroascorbate (DHA), and NAD(P)H/NAD(P)(+), and expression of their metabolism genes was observed, consistent with a decreased reactive oxygen species (ROS) distribution in the root tips. These effects are specific for HO-1, since ZnPPIX blocked the above actions, and the aggravated effects triggered by SA plus ZnPPIX were differentially reversed when carbon monoxide (CO) or bilirubin (BR), two catalytic by-products of HO-1, was added. Together, the results suggest that HO-1 is involved in the SA-induced alleviation of Cd-triggered oxidative stress by re-establishing redox homeostasis.
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Weiti
W
Cui
Le
L
Li
Zhaozhou
Z
Gao
Honghong
H
Wu
Yanjie
Y
Xie
Wenbiao
W
Shen
D000975:Antioxidants / Q000378:metabolism; D002104:Cadmium / Q000633:toxicity*; D002248:Carbon Monoxide / Q000494:pharmacology; D015971:Gene Expression Regulation, Enzymologic / Q000235:genetics*; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D005978:Glutathione / Q000031:analogs & derivatives / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000235:genetics* / Q000378:metabolism; D006427:Hemin / Q000494:pharmacology; D006706:Homeostasis; D015227:Lipid Peroxidation; D000455:Medicago sativa / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D011524:Protoporphyrins / Q000494:pharmacology; D017382:Reactive Oxygen Species / Q000378:metabolism; D020156:Salicylic Acid / Q000494:pharmacology*; D036226:Seedlings / Q000187:drug effects / Q000201:enzymology / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis / Q000378:metabolism; D015854:Up-Regulation
D000975:Antioxidants; D010940:Plant Proteins; D011524:Protoporphyrins; D017382:Reactive Oxygen Species; D017392:Thiobarbituric Acid Reactive Substances; C402172:homoglutathione; D002104:Cadmium; D009243:NAD; C017803:zinc protoporphyrin; D006427:Hemin; D002248:Carbon Monoxide; D051547:Heme Oxygenase-1; D005978:Glutathione; D020156:Salicylic Acid