title: HY5 regulates nitrite reductase 1 (NIR1) and ammonium transporter1;2 (AMT1;2) in Arabidopsis seedlings.
abstract: HY5 (Long Hypocotyles 5) is a key transcription factor in Arabidopsis thaliana that has a pivotal role in seedling development. Soil nitrogen is an essential macronutrient, and its uptake, assimilation and metabolism are influenced by nutrient availability and by lights. To understand the role of HY5 in nitrogen assimilation pathways, we examined the phenotype as well as the expression of selected nitrogen assimilation-related genes in hy5 mutant grown under various nitrogen limiting and nitrogen sufficient conditions, or different light conditions. We report that HY5 positively regulates nitrite reductase gene NIR1 and negatively regulates the ammonium transporter gene AMT1;2 under all nitrogen and light conditions tested, while it affects several other genes in a nitrogen supply-dependent manner. HY5 is not required for light induction of NIR1, AMT1;2 and NIA genes, but it is necessary for high level expression of NIR1 and NIA under optimal nutrient and light conditions. In addition, nitrogen deficiency exacerbates the abnormal root system of hy5. Together, our results suggest that HY5 exhibits the growth-promoting activity only when sufficient nutrients, including lights, are provided, and that HY5 has a complex involvement in nitrogen acquisition and metabolism in Arabidopsis seedlings.
authors.affiliation: Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China; Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA.
authors.forename: Lifen
authors.initials: L
authors.lastname: Huang
authors.affiliation: Jiangsu Key Laboratory of Crop Genetics and Physiology/Co-Innovation Center for Modern Production Technology of Grain Crops, Yangzhou University, Yangzhou 225009, China. Electronic address: hczhang@yzu.edu.cn.
authors.forename: Hongcheng
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA; College of Life Sciences, Henan Agricultural University, Zhengzhou 450002, China.
authors.forename: Huiyong
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA; State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Advanced Agriculture Sciences and School of Life Sciences, Peking University, Beijing 100871, China.
authors.forename: Xing Wang
authors.initials: XW
authors.lastname: Deng
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06520-8104, USA. Electronic address: ning.wei@yale.edu.
authors.forename: Ning
authors.initials: N
authors.lastname: Wei
mesh_terms: D064751:Ammonium Compounds / Q000378:metabolism; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D029681:Arabidopsis Proteins / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors / Q000378:metabolism*; D027682:Cation Transport Proteins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant / Q000187:drug effects / Q000528:radiation effects; D008027:Light; D009154:Mutation / Q000235:genetics; D009572:Nitrite Reductases / Q000378:metabolism*; D009584:Nitrogen / Q000378:metabolism / Q000494:pharmacology; D009687:Nuclear Proteins / Q000378:metabolism*; D010641:Phenotype; D010940:Plant Proteins / Q000378:metabolism*; D018517:Plant Roots / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000378:metabolism*
chemical_list: D064751:Ammonium Compounds; D029681:Arabidopsis Proteins; D050976:Basic-Leucine Zipper Transcription Factors; D027682:Cation Transport Proteins; C109254:HY5 protein, Arabidopsis; D009687:Nuclear Proteins; D010940:Plant Proteins; D012333:RNA, Messenger; C088952:ammonium transporters, plant; C000607454:NIR1 protein, Arabidopsis; D009572:Nitrite Reductases; D009584:Nitrogen
keywords: AMT1 ;2; HY5; Light regulation; Nitrite reductase NIR1; Nitrogen metabolism; Root development