title: Heme oxygenase-1 is involved in the cytokinin-induced alleviation of senescence in detached wheat leaves during dark incubation.
abstract: This study tested whether an inducible isoform of heme oxygenase (HO, EC 1.14.99.3), HO-1, is involved in the cytokinin (CTK)-induced alleviation of senescence in detached wheat (Triticum aestivum L.) leaves during dark incubation. We discovered that exogenous supplement of 6-benzylaminopurine (6-BA) at 10 μM for 48 h not only delayed the dark-induced loss of chlorophyll and protein contents in detached wheat leaves, but also significantly increased HO activity in a time-dependent manner. This induction reached a maximum within 3h of 6-BA supply, which was further confirmed by using semi-quantitative RT-PCR and protein gel blot analysis. Furthermore, the decreases in intracellular thiobarbituric acid reactive substances (TBARS) content, and the increases in the transcript level, total and isozymatic activities of some important antioxidant enzymes, such as catalase (CAT, EC 1.11.1.6), peroxidase (POD, EC 1.11.1.7), superoxide dismutase (SOD, EC 1.15.1.1), and ascorbate peroxidase (APX, EC 1.11.1.11), were observed. Reversed responses of chlorophyll, protein and TBARS contents, HO activity, and the expression of above antioxidant enzymes were observed when zinc protoporphyrin-IX (ZnPPIX), a potent HO-1 inhibitor, was added together with 6-BA. In contrast, HO-1 inducer hemin could partially mimic the effects of 6-BA. Together, the results suggest that HO-1 might be involved in the CTK-induced alleviation of senescence and lipid peroxidation in detached wheat leaves.
authors.affiliation: College of Life Sciences, Cooperative Demonstration Laboratory of Centrifuge Technique, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Jingjing
authors.initials: J
authors.lastname: Huang
authors.forename: Bin
authors.initials: B
authors.lastname: Han
authors.forename: Sheng
authors.initials: S
authors.lastname: Xu
authors.forename: Meixue
authors.initials: M
authors.lastname: Zhou
authors.forename: Wenbiao
authors.initials: W
authors.lastname: Shen
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D060387:Ascorbate Peroxidases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D001593:Benzyl Compounds / Q000494:pharmacology*; D002374:Catalase / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D016922:Cellular Senescence / Q000187:drug effects*; D002734:Chlorophyll / Q000378:metabolism; D003583:Cytokinins / Q000494:pharmacology*; D003624:Darkness; D051547:Heme Oxygenase-1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006427:Hemin / Q000378:metabolism / Q000494:pharmacology; D015227:Lipid Peroxidation / Q000187:drug effects; D010544:Peroxidases / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism / Q000494:pharmacology; D011524:Protoporphyrins / Q000494:pharmacology; D011687:Purines / Q000494:pharmacology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D013997:Time Factors; D014908:Triticum / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism / Q000502:physiology*
chemical_list: D000975:Antioxidants; D001593:Benzyl Compounds; D003583:Cytokinins; D010940:Plant Proteins; D011524:Protoporphyrins; D011687:Purines; D017392:Thiobarbituric Acid Reactive Substances; D002734:Chlorophyll; C017803:zinc protoporphyrin; D006427:Hemin; D010544:Peroxidases; D060387:Ascorbate Peroxidases; D002374:Catalase; D051547:Heme Oxygenase-1; C480551:benzylaminopurine