背景回顾：The genetic improvement of nitrogen use efficiency (NUE) of crops is vital for grain productivity and sustainable agriculture. 

提出问题：However, the regulatory mechanism of NUE remains largely elusive.

主要发现：Here, we find that the rice Grain number, plant height, and heading date7 (Ghd7) gene genetically acts upstream of ABC1 REPRESSOR1 (ARE1), a negative regulator of NUE, to positively regulate nitrogen utilization. 

结果1-作用机制：As a transcriptional repressor, Ghd7 directly binds to two Evening Element-like motifs in the promoter and Intron 1 of ARE1, likely in a cooperative manner, to repress its expression. 

结果2-日表达动态：Ghd7 and ARE1 displaydiurnal expression patterns in an inverse oscillation manner, mirroring a regulatory scheme based on these two loci. 

结果3-群体分析：Analysis of a panel of 2,656 rice varieties suggests that the elite alleles of Ghd7 and ARE1 have undergone diversifying selection during breeding. 

结果4-关联环境：Moreover, the allelic distribution of Ghd7 and ARE1 is associated with the soil nitrogen deposition rate in East Asia and South Asia. 

结果5-聚合育种：Remarkably, the combination of the Ghd7 and ARE1 elite alleles substantially improves NUE and yield performance under nitrogen-limiting conditions. 

结论：These results define a Ghd7-ARE1-based mechanism regulating nitrogen utilization, which may represent useful targets for the genetic improvement of rice nitrogen utilization in breeding.

 摘 要 

作物氮利用效率（NUE）的遗传改良对粮食生产和可持续农业至关重要。然而，NUE的调控机制在很大程度上仍然是未知的。本文中，作者发现水稻的Ghd7基因在遗传上作用于NUE负调控因子ARE1基因的上游，从而正调控氮素利用。Ghd7作为一种转录抑制因子，能够直接结合到ARE1基因的启动子和第一个内含子上的两个Evening Element-like基序，可能以协同方式抑制其表达。Ghd7和ARE1基因以逆振荡的方式表现出日表达模式，反映了基于这两个基因座的调控机制。对2656份水稻种质的群体分析表明，Ghd7和ARE1等位基因在育种过程中经历了多样化的选择。此外，Ghd7和ARE1的等位基因分布与东亚和南亚的土壤氮沉降速率有关。值得注意的是，GHD7和ARE1优良等位基因的组合显著提高了氮限制条件下植株的NUE和产量。本文的研究结果揭示了一个基于Ghd7-ARE1的水稻氮利用调控机制，为水稻氮利用的遗传改良提供了潜在可利用靶点。