학술논문
Localization of NAD-Isocitrate Dehydrogenase and Glutamate Dehydrogenase in Rice Roots: Candidates for Providing Carbon Skeletons to NADH-Glutamate Synthase.
Document Type
Article
Author
Source
Subject
*PLANT roots
*NAD(P)H dehydrogenases
*GLUTAMATE dehydrogenase
*MESSENGER RNA
*MITOCHONDRIAL DNA
RICE genetics
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Language
ISSN
0032-0781
Abstract
In rice roots, transient and cell-type-specific accumulation of both mRNA and protein for NADH-dependent glutamate synthase (NADH-GOGAT) occurs after the supply of NH4+ ions. In order to better understand the origin of 2-oxoglutarate for this reaction, we focused on mitochondrial NAD-dependent isocitrate dehydrogenase (IDH) and glutamate dehydrogenase (GDH) in rice roots. Six rice cDNAs encoding a single catalytic (OsIDHa) and two regulatory (OsIDHc;1, OsIDHc;2) IDH subunits and three GDH proteins (OsGDH1-3) were isolated. These genes, except OsGDH3, were expressed in the roots. Real-time PCR analysis showed that OsIDHa and OsIDHc;1 transcripts, but not OsGDH1 and OsGDH2 transcripts, accumulated in a similar manner to NADH-GOGAT mRNA along the crown roots after the supply of different forms of inorganic nitrogen. Furthermore, immunolocalization studies revealed the NH4+ induction of IDHa protein in two cell layers of the root surface, i.e. epidermis and exodermis, where NADH-GOGAT also accumulated. The possible relationship between NADH-GOGAT, IDH and GDH is discussed. [ABSTRACT FROM AUTHOR]