title: Maize cytosolic NADP-malic enzyme (ZmCytNADP-ME): a phylogenetically distant isoform specifically expressed in embryo and emerging roots.
abstract: Two maize plastidic NADP-malic enzyme isoforms have been characterized: the bundle sheath-located photosynthetic isoform (ZmC(4)-NADP-ME) and a constitutively expressed one (Zm-nonC(4)-NADP-ME). In this work, the characterization of the first maize cytosolic NADP-ME (ZmCytNADP-ME) is presented, which transcript is exclusively found in embryo and emerging roots. ZmCytNADP-ME expression in roots decreases with development, while Zm-nonC ( 4 ) -NADP-ME increases concomitantly. On the other hand, ZmCytNADP-ME accumulation is differentially modulated by several stress conditions and shows coordination with that of Zm-nonC ( 4 ) -NADP-ME in maize young roots. Recombinant ZmCytNADP-ME displays clearly distinct kinetic parameters and metabolic regulation than the plastidic isoforms. The particular properties and the specific-expression pattern of this novel isoform suggest that it may be involved in the control of cytosolic malate levels in emerging roots, e.g. during hypoxia. ZmCytNADP-ME is phylogenetically related to other cytosolic mono and dicot NADP-MEs, and data indicate that it belongs to an ancestral unique group among plant NADP-MEs.
authors.affiliation: Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.
authors.forename: Enrique
authors.initials: E
authors.lastname: Detarsio
authors.forename: Verónica G
authors.initials: VG
authors.lastname: Maurino
authors.forename: Clarisa E
authors.initials: CE
authors.lastname: Alvarez
authors.forename: Gabriela L
authors.initials: GL
authors.lastname: Müller
authors.forename: Carlos S
authors.initials: CS
authors.lastname: Andreo
authors.forename: María F
authors.initials: MF
authors.lastname: Drincovich
mesh_terms: D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D003600:Cytosol / Q000201:enzymology*; D018076:DNA, Complementary / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008291:Malate Dehydrogenase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010802:Phylogeny; D010936:Plant Extracts / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000201:enzymology* / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D012639:Seeds / Q000201:enzymology* / Q000235:genetics; D016415:Sequence Alignment; D013347:Subcellular Fractions / Q000201:enzymology; D003313:Zea mays / Q000166:cytology / Q000201:enzymology* / Q000235:genetics
chemical_list: D018076:DNA, Complementary; D007527:Isoenzymes; D010936:Plant Extracts; D012333:RNA, Messenger; D011994:Recombinant Proteins; D008291:Malate Dehydrogenase; C031917:malate dehydrogenase (oxaloacetate-decarboxylating) (NADP+)