PHR1 negatively regulates nitrate reductase activity by directly inhibiting the transcription of NIA1 in Arabidopsis

Zhongjuan Liu; Shaoxuan Huang; Lin Zhu; Chengquan Li; Duanmei Zhang; Mingxue Chen; Yanan Liu; Yongqiang Zhang

doi:10.1016/j.jplph.2024.154382

PHR1 negatively regulates nitrate reductase activity by directly inhibiting the transcription of NIA1 in Arabidopsis

J Plant Physiol. 2024 Nov 19:303:154382. doi: 10.1016/j.jplph.2024.154382. Online ahead of print.

Authors

Zhongjuan Liu¹, Shaoxuan Huang², Lin Zhu³, Chengquan Li², Duanmei Zhang², Mingxue Chen³, Yanan Liu², Yongqiang Zhang⁴

Affiliations

¹ Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of JunCao Science and Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province Universities, Fuzhou, 350002, China; College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
² Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of JunCao Science and Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
³ Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of JunCao Science and Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
⁴ Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of JunCao Science and Ecology, Fujian Agriculture and Forestry University, Fuzhou, 350002, China; Key Laboratory of Crop Ecology and Molecular Physiology (Fujian Agriculture and Forestry University), Fujian Province Universities, Fuzhou, 350002, China; College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China. Electronic address: yqzhang@fafu.edu.cn.

PMID: 39581121
DOI: 10.1016/j.jplph.2024.154382

Abstract

Nitrogen (N) and phosphorus (P), as indispensable mineral elements, both play pivotal roles in plant growth and development. Despite the intimate association between nitrate signaling and inorganic phosphate (Pi) signaling, the regulatory function of Pi in N metabolism remains poorly understood. In this study, we observed that Pi deficiency leads to a reduction in the activity of nitrate reductase (NR), an essential enzyme involved in N metabolism. Furthermore, PHOSPHATE STARVATION RESPONSE 1 (PHR1), a key regulator of Pi signaling, exerts a negative impact on both NR activity and the expression of its coding gene NIA1. Importantly, our analysis utilizing yeast one-hybrid (Y1H) and electrophoretic mobility shift assay (EMSA) techniques reveals the direct binding of PHR1 to the NIA1 promoter via the P1BS motifs. Subsequent transient transcription expression assay (TTEA) demonstrates PHR1 as a transcriptional suppressor of NIA1. In addition, it was also observed that the SPX (SYG1/Pho81/XPR1) proteins SPX1 and SPX4 can attenuate the transcriptional inhibition of NIA1 by PHR1. Collectively, these findings reveal a mechanism through which PHR1-mediated Pi signal governs N metabolism, thus offering evidence for the precise modulation of plant growth and development via N-P interaction.

Keywords: Arabidopsis; NIA1; Nitrate reductase; P1BS motif; PHR1; Transcriptional regulation.