Characteristics of three cytosolic glutamine synthetases and two NADH-glutamate synthase in ammonium assimilation and nitrogen utilization rice

对水稻胞质谷氨酰胺合成酶（GS1;1、GS1；2和GS1；3）和nadh -谷氨酸合成酶（NADH-GOGAT1和NADH-GOGAT2） 3个同工酶的基因进行了逆向遗传和空间表达分析。OsGS1;OsNADH-GOGAT1和OsNADH-GOGAT1在水稻根系吸收铵的初级同化中起重要作用。另一方面，GS1；1和NADH-GOGAT2可能在自然衰老过程中氮的再动员中起重要作用。代谢物分析数据显示GS1的关键作用；在协调水稻代谢平衡中起着重要作用。OsGS1:3的表达是穗特异性的，表明它可能在籽粒成熟和/或萌发中起重要作用。因此，这些同工酶似乎具有不同的和不重叠的功能，没有一个能够补偿另一个的单独功能。

Reverse genetics and spatial expression of genes encoding the three isoenzymes of cytosolic glutamine synthetase (GS1;1, GS1;2, and GS1;3) and two NADH-glutamatesynthases (NADH-GOGAT1 and NADH-GOGAT2) were characterized in rice. OsGS1;2 and OsNADH-GOGAT1 are important in the primary assimilation of ammonium taken up by rice roots. On the other hand, GS1;1 and NADH-GOGAT2 could be important in remobilization of nitrogen during natural senescence. Metabolite profiling data showed a crucial role of GS1;1 in coordinating metabolic balance in rice. Expression of OsGS1:3 was spikelet-specific, indicating that it is probably important in grain ripening and/or germination. Thus, these isoenzymes seem to possess distinct and non-overlapping functions and none was able to compensate for the individual function of another.