Rice transcription factors regulate nitrogen acquisition by repressing and under high-nitrogen conditions.

INTRODUCTION

Nitrogen is a crucial nutrient for crop growth, yet its utilization efficiency is generally low, leading to resource waste and serious environmental problems. Future agricultural sustainability requires improved crop NUE. In this study, we investigated the functions of the rice transcription factors and in nitrate uptake under high-nitrogen conditions.

METHODS

Hydroponic experiments and field tests were conducted to investigate the effects of and on physiological phenotypes and nitrogen use efficiency. Transcriptome analysis was used to explore the genome-wide transcriptional landscape of the two genes in response to nitrate availability. DNA affinity purification sequencing (DAP-seq) was employed to identify genomic sites bound by , subsequently, yeast one-hybrid and transient expression assays verified the regulatory effects of and on key genes.

RESULTS

The double mutants of and presented significantly greater dry weights, nitrogen contents, total amino acid contents, and nitrate levels than the WT, whereas the single mutants presented no significant differences. These findings indicate the functional redundancy of and in regulating nitrogen uptake and assimilation. and act as transcriptional repressors, negatively regulating the expression of nitrogen absorption-related genes. Furthermore, DAP-seq identified potential targets bound by , highlighting its role in the expression of several nitrogen and phosphorus utilization-related genes. Additionally, field tests shown that and knockout promotes both grain yield and NUE. This study provides potential genetic targets for improving yield and NUE in rice and other crops, laying a significant foundation for future crop improvement.