Molecular physiology of glutamine and glutamate biosynthesis in developing seedlings of conifers

Nitrogen is a limiting factor in tree growth and development. The incorporation of ammonium ions in carbon skeletons is catalyzed by the sequential action of the enzymes glutamine synthetase (GS) and glutamate synthase (GOGAT). Most studies on nitrogen-assimilating enzymes have been reported for annual crop plants. Knowledge of these enzymes in woody plants is much more limited, particularly at the molecular level. Here, we review current available information on glutamine/glutamate biosynthesis and chloroplast development in conifers.