title: Heme oxygenase/carbon monoxide system participates in regulating wheat seed germination under osmotic stress involving the nitric oxide pathway.
abstract: To investigate the mechanism and signaling pathway of carbon monoxide (CO) and hematin in alleviating seed germination inhibition and lipid peroxidation, polyethylene glycol-6000 (PEG) was used to mimic osmotic stress in a series of experiments. The results showed that wheat seeds pretreated with a lower dose of PEG (12.5%) showed higher tolerance against osmotic stress as well as the up-regulation of heme oxygenase (HO, EC 1.14.99.3) and decreased lipid peroxidation during recuperation, compared to those with a higher dose of PEG (50%). Exposure of wheat seeds to 25% PEG, HO-1 inhibitor or specific scavenger of nitric oxide (NO) alone differentially led to seed germination inhibition. The PEG-induced inhibitory effects on seed germination were ameliorated by the HO-1 inducer hematin, CO or NO donor. Additionally, hematin was able to markedly boost the HO/CO system. However, the addition of the HO-1 inhibitor or the specific scavenger of NO not only reversed the protective effects conferred by hematin, but also blocked the up-regulation of HO/CO. In addition, hematin-driven NO production in wheat seeds under osmotic stress was confirmed. Based on these results, we conclude that the endogenous HO/CO signal system is required for the alleviation of osmotic stress-induced wheat seed germination inhibition and lipid peroxidation, which might have a possible interaction with NO.
authors.affiliation: College of Life Sciences, Cooperative Demonstration Laboratory of Centrifuge Technique, Nanjing Agricultural University, Nanjing 210095, PR China.
authors.forename: Yahui
authors.initials: Y
authors.lastname: Liu
authors.forename: Sheng
authors.initials: S
authors.lastname: Xu
authors.forename: Tengfang
authors.initials: T
authors.lastname: Ling
authors.forename: Langlai
authors.initials: L
authors.lastname: Xu
authors.forename: Wenbiao
authors.initials: W
authors.lastname: Shen
mesh_terms: D002248:Carbon Monoxide / Q000378:metabolism*; D018525:Germination; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D009997:Osmotic Pressure / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012639:Seeds / Q000378:metabolism* / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014908:Triticum / Q000378:metabolism* / Q000502:physiology
chemical_list: D017392:Thiobarbituric Acid Reactive Substances; D009569:Nitric Oxide; D002248:Carbon Monoxide; D006419:Heme Oxygenase (Decyclizing)