Collaborative Innovation Center of Henan Grain Crops, Henan Agricultural University, Zhengzhou, 450002, China.
College of Agronomy, Henan Agricultural University, Zhengzhou, 450002, China.
Sci Rep. 2017 Apr 20;7(1):1000. doi: 10.1038/s41598-017-01071-1.
Glutamine synthetase (GS) isozymes play critical roles in nitrogen (N) metabolism. However, the exact relationship between GS and nitrogen use efficiency (NUE) remain unclear. We have selected and compared two wheat cultivars, YM49 and XN509, which were identified as the N-efficient and N-inefficient genotypes, respectively. In this study, agronomical, morphological, physiological and biochemical approaches were performed. The results showed that TaGS1 was high expressed post-anthesis, and TaGS2 was highly expressed pre-anthesis in N-efficient genotype compared to N-inefficient genotype. GS1 and GS2 isozymes were also separated by native-PAGE and found that the spatial and temporal distribution of GS isozymes, their expression of gene and protein subunits in source-sink-flow organs during development periods triggered the pool strength and influenced the N flow. According to the physiological role of GS isozymes, we illustrated four metabolic regulation points, by which acting collaboratively in different organs, accelerating the transport of nutrients to the grain. It suggested that the regulation of GS isozymes may promote flow strength and enhance NUE by a complex C-N metabolic mechanism. The relative activity or amount of GS1 and GS2 isozymes could be a potential marker to predict and select wheat genotypes with enhanced NUE.
谷氨酰胺合成酶（GS）同工酶在氮（N）代谢中发挥着关键作用。然而，GS 与氮利用效率（NUE）的确切关系仍不清楚。我们选择并比较了两个小麦品种，YM49 和 XN509，它们分别被鉴定为氮高效和氮低效基因型。在这项研究中，我们采用了农艺学、形态学、生理学和生物化学方法。结果表明，与氮低效基因型相比，氮高效基因型在花后时期高表达 TaGS1，在花前时期高表达 TaGS2。通过原生质体 PAGE 将 GS1 和 GS2 同工酶分离，发现 GS 同工酶的时空分布及其在源库流器官发育过程中的基因和蛋白亚基表达，引发了库强度并影响了 N 流。根据 GS 同工酶的生理作用，我们说明了四个代谢调控点，这些调控点通过在不同器官中协同作用，加速了养分向籽粒的运输。这表明，GS 同工酶的调控可能通过复杂的 C-N 代谢机制促进流动强度并提高 NUE。GS1 和 GS2 同工酶的相对活性或含量可能是预测和选择具有增强 NUE 的小麦基因型的潜在标记。
