RRC ID 51328
Author Rahantaniaina MS, Li S, Chatel-Innocenti G, Tuzet A, Issakidis-Bourguet E, Mhamdi A, Noctor G.
Title Cytosolic and Chloroplastic DHARs Cooperate in Oxidative Stress-Driven Activation of the Salicylic Acid Pathway.
Journal Plant Physiol.
Abstract The complexity of plant antioxidative systems gives rise to many unresolved questions. One relates to the functional importance of dehydroascorbate reductases (DHARs) in interactions between ascorbate and glutathione. To investigate this issue, we produced a complete set of loss-of-function mutants for the three annotated Arabidopsis (Arabidopsis thaliana) DHARs. The combined loss of DHAR1 and DHAR3 expression decreased extractable activity to very low levels but had little effect on phenotype or ascorbate and glutathione pools in standard conditions. An analysis of the subcellular localization of the DHARs in Arabidopsis lines stably transformed with GFP fusion proteins revealed that DHAR1 and DHAR2 are cytosolic while DHAR3 is chloroplastic, with no evidence for peroxisomal or mitochondrial localizations. When the mutations were introduced into an oxidative stress genetic background (cat2), the dhar1 dhar2 combination decreased glutathione oxidation and inhibited cat2-triggered induction of the salicylic acid pathway. These effects were reversed in cat2 dhar1 dhar2 dhar3 complemented with any of the three DHARs. The data suggest that (1) DHAR can be decreased to negligible levels without marked effects on ascorbate pools, (2) the cytosolic isoforms are particularly important in coupling intracellular hydrogen peroxide metabolism to glutathione oxidation, and (3) DHAR-dependent glutathione oxidation influences redox-driven salicylic acid accumulation.
Volume 174(2)
Pages 956-971
Published 2017-6
DOI 10.1104/pp.17.00317
PII pp.17.00317
PMID 28381499
PMC PMC5462045
MeSH Antioxidants / metabolism Arabidopsis / enzymology* Arabidopsis / metabolism Arabidopsis Proteins / metabolism* Ascorbic Acid / metabolism Cell Death Chloroplasts / enzymology* Cytosol / enzymology* DNA, Bacterial / genetics Genetic Complementation Test Glutathione / metabolism Green Fluorescent Proteins / metabolism Mutagenesis, Insertional / genetics Mutation / genetics Oxidative Stress* Oxidoreductases / metabolism* Phenotype Recombinant Fusion Proteins / metabolism Salicylic Acid / metabolism* Subcellular Fractions / metabolism
IF 6.305
Resource
Arabidopsis / Cultured plant cells, genes pda10894 pda09951 pda11632