Endogenous hydrogen peroxide plays a positive role in the upregulation of heme oxygenase and acclimation to oxidative stress in wheat seedling leaves.
Pretreatment of lower H(2)O(2) doses (0.05, 0.5 and 5 mM) for 24 h was able to dose-dependently attenuate lipid peroxidation in wheat seedling leaves mediated by further oxidative damage elicited by higher dose of H(2)O(2) (150 mM) for 6 h, with 0.5 mM H(2)O(2) being the most effective concentrations. Further results illustrated that 0.5 mM H(2)O(2) pretreatment triggered the biphasic production of H(2)O(2) during a 24 h period. We also noticed that only peak I (0.25 h) rather than peak II (4 h) was approximately consistent with the enhancement of heme oxygenase (HO) activity, HO-1 gene expression. Meanwhile, enhanced superoxide dismutase (SOD) activity, Mn-SOD and Cu,Zn-SOD transcripts might be a potential source of peak I of endogenous H(2)O(2). Further results confirmed that 0.5 mM H(2)O(2) treatment for 0.5 h was able to upregulate HO gene expression, which was detected by enzyme activity determination, semi-quantitative reverse transcription-polymerase chain reaction and western blotting. Meanwhile, the application of N,N'-dimethylthiourea, a trap for endogenous H(2)O(2), not only blocked the upregulation of HO, but also reversed the corresponding oxidation attenuation. Together, the above results suggest that endogenous H(2)O(2) production (peak I) plays a positive role in the induction of HO by enhancing its mRNA level and protein expression, thus leading to the acclimation to oxidative stress.
College of Life Sciences, Cooperative Demonstration Laboratory of Centrifuge Technique Nanjing Agricultural University, Nanjing 210095, China.
Xiao-Yue
XY
Chen
Xiao
X
Ding
Sheng
S
Xu
Ren
R
Wang
Wei
W
Xuan
Ze-Yu
ZY
Cao
Jian
J
Chen
Hong-Hong
HH
Wu
Mao-Bing
MB
Ye
Wen-Biao
WB
Shen
D002248:Carbon Monoxide / Q000633:toxicity; D016166:Free Radical Scavengers / Q000494:pharmacology; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D051547:Heme Oxygenase-1 / Q000235:genetics; D006861:Hydrogen Peroxide / Q000378:metabolism* / Q000494:pharmacology*; D015227:Lipid Peroxidation / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D018515:Plant Leaves / Q000187:drug effects / Q000378:metabolism*; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects; D013890:Thiourea / Q000031:analogs & derivatives / Q000494:pharmacology; D014908:Triticum / Q000187:drug effects / Q000378:metabolism*; D015854:Up-Regulation
D016166:Free Radical Scavengers; D002248:Carbon Monoxide; C038983:1,3-dimethylthiourea; D006861:Hydrogen Peroxide; D006419:Heme Oxygenase (Decyclizing); D051547:Heme Oxygenase-1; D013890:Thiourea