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The coordinated utilization of nitrogen(N)and phosphorus(P)is vital for plants to maintain nutrient balance and achieve optimal growth.Previously,we revealed a mechanism by which nitrate induces genes for phos-phate utilization;this mechanism depends on NRT1.1B-facilitated degradation of cytoplasmic SPX4,which in turn promotes cytoplasmic-nuclear shuttling of PHR2,the central transcription factor of phosphate signaling,and triggers the nitrate-induced phosphate response(NIPR)and N-P coordinated utilization in rice.In this study,we unveiled a fine-tuning mechanism of NIPR in the nucleus regulated by Highly Induced by Nitrate Gene 1(HINGE1,also known as RLI1),a MYB-transcription factor closely related to PHR2.RLI1/HINGE1,which is transcriptionally activated by PHR2 under nitrate induction,can directly activate the expression of phosphate starvation-induced genes.More importantly,RLI1/HINGE1 competes with PHR2 for binding to its repressor proteins in the nucleus(SPX proteins),and consequently releases PHR2 to further enhance phosphate response.Therefore,RLI1/HINGE1 amplifies the phosphate response in the nucleus downstream of the cytoplasmic SPX4-PHR2 cascade,thereby enabling fine-tuning of N-P balance when nitrate supply is sufficient.