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.
Chen
Xiao-Yue
XY
College of Life Sciences, Cooperative Demonstration Laboratory of Centrifuge Technique Nanjing Agricultural University, Nanjing 210095, China.
Ding
Xiao
X
Xu
Sheng
S
Wang
Ren
R
Xuan
Wei
W
Cao
Ze-Yu
ZY
Chen
Jian
J
Wu
Hong-Hong
HH
Ye
Mao-Bing
MB
Shen
Wen-Biao
WB
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