Relationship between proline and Hg2+-induced oxidative stress in a tolerant rice mutant.
There has been little agreement regarding the mechanism by which proline reduces heavy metal stress. The present work examines the relationship between Hg(2+)-induced oxidative stress and proline accumulation in rice and explores the possible mechanisms through which proline protects against Hg(2+) stress. The effect of proline on alleviation of Hg(2+) toxicity was studied by spectrophotography and enzymatic methods. Hg(2+) induced oxidative stress in rice by increasing lipid peroxidation. Pretreatment of the rice with 2 mM proline for 12 h profoundly alleviated Hg(2+)-induced lipid peroxidation and minimized H(2)O(2) accumulation. Proline pretreatment significantly reduced (p < 0.01) the Hg(2+) content in rice leaves. A comparison of the effects of proline pretreatment on H(2)O(2) accumulation by Hg(2+) and aminotrazole suggested that proline protected cells from Hg(2+)-induced oxidative stress by scavenging reactive oxygen species. The present work demonstrates a protective effect of proline on Hg(2+) toxicity through detoxifying reactive oxygen species, rather than chelating metal ions or maintaining the water balance under Hg(2+) stress.
Wang
Feijuan
F
State Key Laboratory of Plant Physiology & Biochemistry, College of Life Sciences, Zhejiang University, Hangzhou, China.
Zeng
Bin
B
Sun
Zongxiu
Z
Zhu
Cheng
C
D000222:Adaptation, Physiological / Q000235:genetics; D000975:Antioxidants / Q000032:analysis / Q000494:pharmacology*; D002734:Chlorophyll / Q000032:analysis / Q000378:metabolism; D005978:Glutathione / Q000032:analysis / Q000378:metabolism; D017669:Mercury Compounds / Q000633:toxicity*; D009154:Mutation; D012275:Oryza / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects*; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism; D011392:Proline / Q000378:metabolism / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D014867:Water / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D000975:Antioxidants; D017669:Mercury Compounds; D017382:Reactive Oxygen Species; D014874:Water Pollutants, Chemical; D014867:Water; D002734:Chlorophyll; D011392:Proline; D005978:Glutathione