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Plant Mol Biol. 2008 Nov;68(4-5):355-67. doi: 10.1007/s11103-008-9375-8. Epub 2008 Jul 13.

Maize cytosolic NADP-malic enzyme (ZmCytNADP-ME): a phylogenetically distant isoform specifically expressed in embryo and emerging roots.

Author information

1
Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), Universidad Nacional de Rosario, Suipacha 531, 2000 Rosario, Argentina.

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.

PMID:
18622731
DOI:
10.1007/s11103-008-9375-8
[Indexed for MEDLINE]

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