title: The Arabidopsis NRG2 Protein Mediates Nitrate Signaling and Interacts with and Regulates Key Nitrate Regulators.
abstract: We show that NITRATE REGULATORY GENE2 (NRG2), which we identified using forward genetics, mediates nitrate signaling in Arabidopsis thaliana. A mutation in NRG2 disrupted the induction of nitrate-responsive genes after nitrate treatment by an ammonium-independent mechanism. The nitrate content in roots was lower in the mutants than in the wild type, which may have resulted from reduced expression of NRT1.1 (also called NPF6.3, encoding a nitrate transporter/receptor) and upregulation of NRT1.8 (also called NPF7.2, encoding a xylem nitrate transporter). Genetic and molecular data suggest that NRG2 functions upstream of NRT1.1 in nitrate signaling. Furthermore, NRG2 directly interacts with the nitrate regulator NLP7 in the nucleus, but nuclear retention of NLP7 in response to nitrate is not dependent on NRG2. Transcriptomic analysis revealed that genes involved in four nitrogen-related clusters including nitrate transport and response to nitrate were differentially expressed in the nrg2 mutants. A nitrogen compound transport cluster containing some members of the NRT/PTR family was regulated by both NRG2 and NRT1.1, while no nitrogen-related clusters showed regulation by both NRG2 and NLP7. Thus, NRG2 plays a key role in nitrate regulation in part through modulating NRT1.1 expression and may function with NLP7 via their physical interaction.
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Na
authors.identifier: http://orcid.org/0000-0003-0896-4296
authors.initials: N
authors.lastname: Xu
authors.affiliation: National Key Laboratory of Crop Genetic Improvement, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China Section of Cell and Developmental Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, California 92093-0116.
authors.forename: Rongchen
authors.identifier: http://orcid.org/0000-0002-6378-7504
authors.initials: R
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Lufei
authors.initials: L
authors.lastname: Zhao
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Chengfei
authors.initials: C
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Zehui
authors.initials: Z
authors.lastname: Li
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Zhao
authors.initials: Z
authors.lastname: Lei
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Liu
authors.affiliation: Section of Cell and Developmental Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, California 92093-0116.
authors.forename: Peizhu
authors.initials: P
authors.lastname: Guan
authors.affiliation: State Key Laboratory of Crop Biology, College of Agronomic Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China.
authors.forename: Zhaohui
authors.identifier: http://orcid.org/0000-0001-8320-7872
authors.initials: Z
authors.lastname: Chu
authors.affiliation: Section of Cell and Developmental Biology, Division of Biological Sciences, University of California at San Diego, La Jolla, California 92093-0116.
authors.forename: Nigel M
authors.initials: NM
authors.lastname: Crawford
authors.affiliation: State Key Laboratory of Crop Biology, College of Life Sciences, Shandong Agricultural University, Tai'an, Shandong 271018, China wangyong@sdau.edu.cn.
authors.forename: Yong
authors.identifier: http://orcid.org/0000-0003-0219-4403
authors.initials: Y
authors.lastname: Wang
mesh_terms: D027321:Anion Transport Proteins / Q000235:genetics / Q000378:metabolism; D017360:Arabidopsis / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism; D002874:Chromosome Mapping; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D000091285:Nitrate Transporters; D009566:Nitrates / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism*; D010641:Phenotype; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction
chemical_list: D027321:Anion Transport Proteins; D029681:Arabidopsis Proteins; D047908:Intracellular Signaling Peptides and Proteins; C000624147:NRG2 protein, Arabidopsis; C101492:NRT1.1 protein, Arabidopsis; C552677:NRT1.8 protein, Arabidopsis; D000091285:Nitrate Transporters; D009566:Nitrates; D010940:Plant Proteins; D009584:Nitrogen