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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.
Plant Physiol 2008; 147(2):562-72PP

Abstract

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.

Authors+Show Affiliations

Instituto de Bioquímica Vegetal y Fotosíntesis, Consejo Superior de Investigaciones Científicas and Universidad de Sevilla, 41092 Sevilla, Spain.No affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

18441224

Citation

López-Martín, M Carmen, et al. "Knocking Out Cytosolic Cysteine Synthesis Compromises the Antioxidant Capacity of the Cytosol to Maintain Discrete Concentrations of Hydrogen Peroxide in Arabidopsis." Plant Physiology, vol. 147, no. 2, 2008, pp. 562-72.
López-Martín MC, Becana M, Romero LC, et al. Knocking out cytosolic cysteine synthesis compromises the antioxidant capacity of the cytosol to maintain discrete concentrations of hydrogen peroxide in Arabidopsis. Plant Physiol. 2008;147(2):562-72.
López-Martín, M. C., Becana, M., Romero, L. C., & Gotor, C. (2008). Knocking out cytosolic cysteine synthesis compromises the antioxidant capacity of the cytosol to maintain discrete concentrations of hydrogen peroxide in Arabidopsis. Plant Physiology, 147(2), pp. 562-72. doi:10.1104/pp.108.117408.
López-Martín MC, et al. Knocking Out Cytosolic Cysteine Synthesis Compromises the Antioxidant Capacity of the Cytosol to Maintain Discrete Concentrations of Hydrogen Peroxide in Arabidopsis. Plant Physiol. 2008;147(2):562-72. PubMed PMID: 18441224.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Knocking out cytosolic cysteine synthesis compromises the antioxidant capacity of the cytosol to maintain discrete concentrations of hydrogen peroxide in Arabidopsis. AU - López-Martín,M Carmen, AU - Becana,Manuel, AU - Romero,Luis C, AU - Gotor,Cecilia, Y1 - 2008/04/25/ PY - 2008/4/29/pubmed PY - 2008/8/6/medline PY - 2008/4/29/entrez SP - 562 EP - 72 JF - Plant physiology JO - Plant Physiol. VL - 147 IS - 2 N2 - 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. SN - 0032-0889 UR - https://www.unboundmedicine.com/medline/citation/18441224/Knocking_out_cytosolic_cysteine_synthesis_compromises_the_antioxidant_capacity_of_the_cytosol_to_maintain_discrete_concentrations_of_hydrogen_peroxide_in_Arabidopsis_ L2 - http://www.plantphysiol.org/cgi/pmidlookup?view=long&pmid=18441224 DB - PRIME DP - Unbound Medicine ER -