The coordinated utilization of nitrogen (N) and phosphorus (P) is vital to maintain nutrient balance and achieve an optimal growth for plants. Previously, we revealed a mechanism by which nitrate induces genes for phosphate utilization depending on NRT1.1B-facilitated degradation of cytoplasmic SPX4, thus promoting cytoplasmic-nuclear shuttling of PHR2, the central transcription factor of phosphate signaling, and triggering nitrate-induced phosphate response (NIPR) and N-P coordinated utilization in rice. Here we further unveil a working mechanism for fine-tuning NIPR in nucleus by Highly Induced by Nitrate Gene 1 (HINGE1, also known as RLI1), a MYB-transcription factor closely clustered to PHR2. RLI1/HINGE1 is transcriptionally activated by PHR2 under nitrate induction and can directly activate the expression of phosphate starvation induced genes. More importantly, RLI1/HINGE1 competes with PHR2 to bind its repressor proteins in nucleus (SPX proteins), and consequently releases PHR2 to further enhance phosphate response. Therefore, RLI1/HINGE1 amplifies the phosphate response in nucleus after cytoplasmic SPX4-PHR2 cascade, thereby enabling a fine-tuning of N-P balance under sufficient supply of nitrate.