title: Cytosolic ascorbate peroxidase 1 protects organelles against oxidative stress by wounding- and jasmonate-induced H(2)O(2) in Arabidopsis plants.
abstract: BACKGROUND
  Reactive oxygen species (ROS) are not only cytotoxic compounds leading to oxidative damage, but also signaling molecules for regulating plant responses to stress and hormones. Arabidopsis cytosolic ascorbate peroxidase 1 (APX1) is thought to be a central regulator for cellular ROS levels. However, it remains unclear whether APX1 is involved in plant tolerance to wounding and methyl jasmonate (MeJA) treatment, which are known to enhance ROS production.
  
  
  METHODS
  We studied the effect of wounding and MeJA treatment on the levels of H(2)O(2) and oxidative damage in the Arabidopsis wild-type plants and knockout mutants lacking APX1 (KO-APX1).
  
  
  RESULTS
  The KO-APX1 plants showed high sensitivity to wounding and MeJA treatment. In the leaves of wild-type plants, H(2)O(2) accumulated only in the vicinity of the wound, while in the leaves of the KO-APX1 plants it accumulated extensively from damaged to undamaged regions. During MeJA treatment, the levels of H(2)O(2) were much higher in the leaves of KO-APX1 plants. Oxidative damage in the chloroplasts and nucleus was also enhanced in the leaves of KO-APX1 plants. These findings suggest that APX1 protects organelles against oxidative stress by wounding and MeJA treatment.
  
  
  CONCLUSIONS
  This is the first report demonstrating that H(2)O(2)-scavenging in the cytosol is essential for plant tolerance to wounding and MeJA treatment.
authors.affiliation: Department of Advanced Bioscience, Kinki University, Nara, Japan.
authors.forename: Takanori
authors.initials: T
authors.lastname: Maruta
authors.forename: Takahiro
authors.initials: T
authors.lastname: Inoue
authors.forename: Masahiro
authors.initials: M
authors.lastname: Noshi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Tamoi
authors.forename: Yukinori
authors.initials: Y
authors.lastname: Yabuta
authors.forename: Kazuya
authors.initials: K
authors.lastname: Yoshimura
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ishikawa
authors.forename: Shigeru
authors.initials: S
authors.lastname: Shigeoka
mesh_terms: D000085:Acetates / Q000494:pharmacology*; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D002734:Chlorophyll / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology*; D003600:Cytosol / Q000201:enzymology*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D015388:Organelles / Q000187:drug effects / Q000502:physiology*; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D054883:Oxylipins / Q000494:pharmacology*; D010935:Plant Diseases / Q000235:genetics / Q000517:prevention & control; D010937:Plant Growth Regulators / Q000494:pharmacology; D030821:Plants, Genetically Modified / Q000201:enzymology / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D018749:RNA, Plant / Q000235:genetics; D017382:Reactive Oxygen Species / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014945:Wound Healing
chemical_list: D000085:Acetates; D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D054883:Oxylipins; D010937:Plant Growth Regulators; D012333:RNA, Messenger; D018749:RNA, Plant; D017382:Reactive Oxygen Species; D002734:Chlorophyll; C072239:methyl jasmonate; D006861:Hydrogen Peroxide; C555290:APX1 protein, Arabidopsis; D060387:Ascorbate Peroxidases