title: NADPH thioredoxin reductase C is localized in plastids of photosynthetic and nonphotosynthetic tissues and is involved in lateral root formation in Arabidopsis.
abstract: Plastids are organelles present in photosynthetic and nonphotosynthetic plant tissues. While it is well known that thioredoxin-dependent redox regulation is essential for leaf chloroplast function, little is known of the redox regulation in plastids of nonphotosynthetic tissues, which cannot use light as a direct source of reducing power. Thus, the question remains whether redox regulation operates in nonphotosynthetic plastid function and how it is integrated with chloroplasts for plant growth. Here, we show that NADPH-thioredoxin reductase C (NTRC), previously reported as exclusive to green tissues, is also expressed in nonphotosynthetic tissues of Arabidopsis thaliana, where it is localized to plastids. Moreover, we show that NTRC is involved in maintaining the redox homeostasis of plastids also in nonphotosynthetic organs. To test the relationship between plastids of photosynthetic and nonphotosynthetic tissues, transgenic plants were obtained with redox homeostasis restituted exclusively in leaves or in roots, through the expression of NTRC under the control of organ-specific promoters in the ntrc mutant. Our results show that fully functional root amyloplasts are not sufficient for root, or leaf, growth, but fully functional chloroplasts are necessary and sufficient to support wild-type rates of root growth and lateral root formation.
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-Consejo Superior de Investigaciones Cientificas, 41092 Sevilla, Spain.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Kirchsteiger
authors.forename: Julia
authors.initials: J
authors.lastname: Ferrández
authors.forename: María Belén
authors.initials: MB
authors.lastname: Pascual
authors.forename: Maricruz
authors.initials: M
authors.lastname: González
authors.forename: Francisco Javier
authors.initials: FJ
authors.lastname: Cejudo
mesh_terms: D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D005966:Glucuronidase / Q000378:metabolism; D006706:Homeostasis; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D009928:Organ Specificity / Q000235:genetics; D010084:Oxidation-Reduction; D010788:Photosynthesis / Q000235:genetics; D018515:Plant Leaves / Q000201:enzymology; D018517:Plant Roots / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development*; D018087:Plastids / Q000201:enzymology* / Q000235:genetics; D021381:Protein Transport; D036226:Seedlings / Q000201:enzymology / Q000254:growth & development; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000201:enzymology; D013880:Thioredoxin-Disulfide Reductase / Q000235:genetics / Q000378:metabolism*; D014170:Transformation, Genetic
chemical_list: D029681:Arabidopsis Proteins; D013880:Thioredoxin-Disulfide Reductase; D005966:Glucuronidase