Glutamine synthetase-glutamate synthase pathway and glutamate dehydrogenase play distinct roles in the sink-source nitrogen cycle in tobacco.

Glutamate (Glu) metabolism and amino acid translocation were investigated in the young and old leaves of tobacco (Nicotiana tabacum L. cv Xanthi) using [15N]ammonium and [2-15N]Glu tracers. Regardless of leaf age, [15N]ammonium assimilation occurred via glutamine synthetase (GS; EC 6.

Expression of a ferredoxin-dependent glutamate synthase gene in mesophyll and vascular cells and functions of the enzyme in ammonium assimilation in Nicotiana tabacum (L.).

GLU1 encodes the major ferredoxin-dependent glutamate synthase (Fd-GOGAT, EC 1.4.7.