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Knocking Out Cytosolic Cysteine Synthesis Compromises the Antioxidant Capacity of the Cytosol to Maintain Discrete Concentrations of Hydrogen Peroxide in Arabidopsis

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dc.creator López-Martín, M. Carmen
dc.creator Becana Ausejo, Manuel
dc.creator Romero, Luis C.
dc.creator Gotor, Cecilia
dc.date 2008-07-03T11:04:32Z
dc.date 2008-07-03T11:04:32Z
dc.date 2008-04
dc.date.accessioned 2017-01-31T02:23:10Z
dc.date.available 2017-01-31T02:23:10Z
dc.identifier Plant Physiology 147:562-572 (2008)
dc.identifier 0032-0889
dc.identifier http://hdl.handle.net/10261/5569
dc.identifier 10.1104/pp.108.117408
dc.identifier.uri http://dspace.mediu.edu.my:8181/xmlui/handle/10261/5569
dc.description First published online April 25, 2008
dc.description Plant cells contain different O-acetylserine(thiol)lyase (OASTL) enzymes involved in cysteine (Cys) biosynthesis and located in different subcellular compartments. These enzymes are made up of a complex variety of isoforms resulting in different subcellular Cys pools. To unravel the contribution of cytosolic Cys to plant metabolism, we characterized the knockout oas-a1.1 and osa-a1.2 mutants, deficient in the most abundant cytosolic OASTL isoform in Arabidopsis (Arabidopsis thaliana). Total intracellular Cys and glutathione concentrations were reduced, and the glutathione redox state was shifted in favor of its oxidized form. Interestingly, the capability of the mutants to chelate heavy metals did not differ from that of the wild type, but the mutants have an enhanced sensitivity to cadmium. With the aim of establishing the metabolic network most influenced by the cytosolic Cys pool, we used the ATH1 GeneChip for evaluation of differentially expressed genes in the oas-a1.1 mutant grown under nonstress conditions. The transcriptomic footprints of mutant plants had predicted functions associated with various physiological responses that are dependent on reactive oxygen species and suggested that the mutant was oxidatively stressed. Evidences that the mutation caused a perturbation in H2O2 homeostasis are that, in the knockout, H2O2 production was localized in shoots and roots; spontaneous cell death lesions occurred in the leaves; and lignification and guaiacol peroxidase activity were significantly increased. All these findings indicate that a deficiency of OAS-A1 in the cytosol promotes a perturbation in H2O2 homeostasis and that Cys is an important determinant of the antioxidative capacity of the cytosol in Arabidopsis.
dc.description This work was supported by Ministerio de Educación y Ciencia (grant nos. BIO2004–00784, BIO2007–62770, and AGL2005–01404) and Junta de Andalucía (grant no. CVI–273), Spain.
dc.description Peer reviewed
dc.format 21366 bytes
dc.format application/pdf
dc.language eng
dc.publisher American Society of Plant Biologists
dc.rights openAccess
dc.title Knocking Out Cytosolic Cysteine Synthesis Compromises the Antioxidant Capacity of the Cytosol to Maintain Discrete Concentrations of Hydrogen Peroxide in Arabidopsis
dc.type Artículo


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