title: Lack of malate valve capacities lead to improved N-assimilation and growth in transgenic A. thaliana plants.
abstract: In this study we analyzed the relationship between malate valve capacities, N-assimilation, and energy metabolism. We used transgenic plants either lacking the chloroplast NADP-dependent malate dehydrogenase or mutants with a decreased transcript level of the plastid-localized NAD-dependent malate dehydrogenase. Plants were grown on nitrate or ammonium, respectively, as the sole N-source and transcripts were analyzed by qRT-PCR. We could show that the lack of malate valve capacities enhances N-assimilation and plastidial glycolysis by increasing transcript levels of Fd-GOGATs or NADH-GOGAT and plastidic NAD-GAPDHs (GapCps), respectively. Based on our results, we conclude that the lack of malate valve capacities is balanced by an increase of the activity of plastid-localized glycolysis in order to cover the high demand for plastidial ATP, stressing the importance of the plastids for energy metabolism in plant cells.
authors.affiliation: a Department of Plant Physiology; University of Osnabrueck; Osnabrueck, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Selinski
authors.forename: Renate
authors.initials: R
authors.lastname: Scheibe
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D000594:Amino Acid Oxidoreductases / Q000378:metabolism; D017360:Arabidopsis / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D002736:Chloroplasts / Q000378:metabolism*; D004734:Energy Metabolism; D050790:Glutamate Synthase (NADH) / Q000378:metabolism; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating) / Q000378:metabolism; D006019:Glycolysis; D008291:Malate Dehydrogenase / Q000378:metabolism*; D008293:Malates / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D030821:Plants, Genetically Modified
chemical_list: D029681:Arabidopsis Proteins; D008293:Malates; C030298:malic acid; D000255:Adenosine Triphosphate; D008291:Malate Dehydrogenase; D024581:Glyceraldehyde-3-Phosphate Dehydrogenase (Phosphorylating); D000594:Amino Acid Oxidoreductases; D050790:Glutamate Synthase (NADH); C042233:glutamate synthase (ferredoxin); D009584:Nitrogen
keywords: ammonium assimilation; energy supply; malate valve; nitrate assimilation; plastidial glycolysis; redox-balance