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PMID:15608336

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Citation

Davletova, S, Rizhsky, L, Liang, H, Shengqiang, Z, Oliver, DJ, Coutu, J, Shulaev, V, Schlauch, K and Mittler, R (2005) Cytosolic ascorbate peroxidase 1 is a central component of the reactive oxygen gene network of Arabidopsis. Plant Cell 17:268-81

Abstract

Reactive oxygen species (ROS), such as O2- and H2O2, play a key role in plant metabolism, cellular signaling, and defense. In leaf cells, the chloroplast is considered to be a focal point of ROS metabolism. It is a major producer of O2- and H2O2 during photosynthesis, and it contains a large array of ROS-scavenging mechanisms that have been extensively studied. By contrast, the function of the cytosolic ROS-scavenging mechanisms of leaf cells is largely unknown. In this study, we demonstrate that in the absence of the cytosolic H2O2-scavenging enzyme ascorbate peroxidase 1 (APX1), the entire chloroplastic H2O2-scavenging system of Arabidopsis thaliana collapses, H2O2 levels increase, and protein oxidation occurs. We further identify specific proteins oxidized in APX1-deficient plants and characterize the signaling events that ensue in knockout-Apx1 plants in response to a moderate level of light stress. Using a dominant-negative approach, we demonstrate that heat shock transcription factors play a central role in the early sensing of H2O2 stress in plants. Using knockout plants for the NADPH oxidase D protein (knockout-RbohD), we demonstrate that RbohD might be required for ROS signal amplification during light stress. Our study points to a key role for the cytosol in protecting the chloroplast during light stress and provides evidence for cross-compartment protection of thylakoid and stromal/mitochondrial APXs by cytosolic APX1.

Links

PubMed PMC544504 Online version:10.1105/tpc.104.026971

Keywords

Arabidopsis/enzymology; Arabidopsis/genetics; Arabidopsis Proteins/genetics; Arabidopsis Proteins/metabolism; Ascorbate Peroxidases; Chloroplast Proteins; Chloroplasts/enzymology; Chloroplasts/genetics; Cytosol/enzymology; Gene Expression Regulation, Plant/genetics; Hydrogen Peroxide/metabolism; Light; Mitochondria/enzymology; Mitochondria/genetics; NADPH Oxidase/genetics; NADPH Oxidase/metabolism; Peroxidases/genetics; Peroxidases/metabolism; Photic Stimulation; Plant Leaves/enzymology; Plant Leaves/genetics; Reactive Oxygen Species/metabolism; Thylakoids/enzymology; Thylakoids/genetics

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status

ARATH:APX1

acts_upstream_of_or_within

GO:0000302: response to reactive oxygen species

ECO:0000315: mutant phenotype evidence used in manual assertion

P

Seeded From UniProt

complete

ARATH:APX1

enables

GO:0016688: L-ascorbate peroxidase activity

ECO:0000315: mutant phenotype evidence used in manual assertion

F

Seeded From UniProt

complete

ARATH:APX1

acts_upstream_of_or_within

GO:0042744: hydrogen peroxide catabolic process

ECO:0000315: mutant phenotype evidence used in manual assertion

P

Seeded From UniProt

complete

ARATH:CATA1

acts_upstream_of_or_within

GO:0009416: response to light stimulus

ECO:0000270: expression pattern evidence used in manual assertion

P

Seeded From UniProt

complete

ARATH:RBOHD

enables

GO:0016174: NAD(P)H oxidase H2O2-forming activity

ECO:0000304: author statement supported by traceable reference used in manual assertion

F

Seeded From UniProt

complete

ARATH:RBOHD

enables

GO:0016174: NAD(P)H oxidase activity

ECO:0000304: author statement supported by traceable reference used in manual assertion

F

Seeded From UniProt

complete

See also

References

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