Nitrogen (N) is the most abundant mineral element in plants and often constitutes a major limiting factor in agricultural practice.The application of N fertilizer has greatly enhanced the global crop production,but the accompanying economic and environmental costs are becoming unaffordable.Rice is the staple food for more than half of world population;therefore,understanding the molecular mechanisms regulating N uptake and utilization and thereby developing the strategies to improve the N use efficiency (NUE) in rice have become urgently needed.