title: Comparative changes in the antioxidant system in the flag leaf of early and normally senescing near-isogenic lines of wheat (Triticum aestivum L.).
abstract: The antioxidant system was significantly inhibited in the early aging line than the near-isogenic normal aging line during senescence. The antioxidant system plays pivotal roles in removal of reactive oxygen species (ROS) produced during leaf senescence. To explore its roles in leaf senescence of wheat (Triticum aestivum L.), the concentrations of antioxidants, activities, and gene expression of antioxidant enzymes were evaluated in flag leaves of the early aging line (EAL) and the near-isogenic normal aging line (NL) during senescence. The results showed that the total chlorophyll and soluble protein in the EAL declined earlier and faster, while more malondialdehyde and ROS accumulated compared with the NL. The activities of superoxide dismutase, catalase, ascorbate peroxidase, dehydroascorbate reductase, and glutathione reductase were lower in the EAL than in the NL across multiple measuring dates. Additionally, the EAL had less amounts of reduced ascorbate and glutathione as well as lower reduction state with the progression of senescence. Concomitantly, the gene expression of antioxidant enzymes in the EAL was also significantly repressed relative to those in the NL during natural senescence. Taken together, the earlier onset and faster rate of senescence in the EAL could be a result of an imbalance of ROS production and ROS-scavenging antioxidant system, which provided valuable hints toward understanding leaf senescence of wheat.
authors.affiliation: State Key Laboratory of Plant Cell and Chromosome Engineering, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, No. 1 West Beichen Road, Chaoyang District, Beijing, 100101, China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Li
authors.forename: Gui
authors.initials: G
authors.lastname: Wang
authors.forename: Shudong
authors.initials: S
authors.lastname: Liu
authors.forename: Qiang
authors.initials: Q
authors.lastname: An
authors.forename: Qi
authors.initials: Q
authors.lastname: Zheng
authors.forename: Bin
authors.initials: B
authors.lastname: Li
authors.forename: Zhensheng
authors.initials: Z
authors.lastname: Li
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000235:genetics / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D004798:Enzymes / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D005978:Glutathione / Q000378:metabolism; D005980:Glutathione Reductase / Q000235:genetics / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D014908:Triticum / Q000378:metabolism / Q000502:physiology*
chemical_list: D000975:Antioxidants; D004798:Enzymes; D010940:Plant Proteins; D017382:Reactive Oxygen Species; D002734:Chlorophyll; D008315:Malondialdehyde; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005978:Glutathione