Abstract
Glutamate synthase(GOGAT) reaction requires carbon skeleton in the form 2-oxoglutarate(2-OG). However, the precise origin of 2-OG for this reaction is not well understood. We have focused on two 2-OG-producing enzymes in rice: NAD-isocitrate dehydrogenase (IDH; OsIDHa, OsIDHc;1, OsIDHc;2) and NADH dependent glutamate dehydrogenase (GDH; OsGDH1, OsGDH2, OsGDH3).
Real time PCR analysis showed that the expression profile of OsIDHa and OsIDHc;1 was similar to that of OsNADH-GOGAT. These gene transcripts dramatically increased within 3 hours in the roots following the supply of 1mM or 25mM NH4Cl. Marked increase in accumulation of OsGDH1 was also observed at 6 hours and OsGDH2 at 12 hours after the supply of NH4Cl.Immunolocalization studies for IDHa and GDH proteins in root tips are now in progress.
