title: Arabidopsis AtbHLH112 regulates the expression of genes involved in abiotic stress tolerance by binding to their E-box and GCG-box motifs.
abstract: Plant basic helix-loop-helix (bHLH) transcription factors play essential roles in abiotic stress tolerance. However, most bHLHs have not been functionally characterized. Here, we characterized the functional role of a bHLH transcription factor from Arabidopsis, AtbHLH112, in response to abiotic stress. AtbHLH112 is a nuclear-localized protein, and its nuclear localization is induced by salt, drought and abscisic acid (ABA). In addition, AtbHLH112 serves as a transcriptional activator, with the activation domain located at its N-terminus. In addition to binding to the E-box motifs of stress-responsive genes, AtbHLH112 binds to a novel motif with the sequence 'GG[GT]CC[GT][GA][TA]C' (GCG-box). Gain- and loss-of-function analyses showed that the transcript level of AtbHLH112 is positively correlated with salt and drought tolerance. AtbHLH112 mediates stress tolerance by increasing the expression of P5CS genes and reducing the expression of P5CDH and ProDH genes to increase proline levels. AtbHLH112 also increases the expression of POD and SOD genes to improve reactive oxygen species (ROS) scavenging ability. We present a model suggesting that AtbHLH112 is a transcriptional activator that regulates the expression of genes via binding to their GCG- or E-boxes to mediate physiological responses, including proline biosynthesis and ROS scavenging pathways, to enhance stress tolerance.
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China.|Key Laboratory of Food Science and Engineering, Harbin University of Commerce, 1 Xuehai Street, 150028, Harbin, Heilongjiang, China.
authors.forename: Yujia
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 830011, Urumqi, Xinjiang, China.
authors.forename: Xiaoyu
authors.initials: X
authors.lastname: Ji
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China.
authors.forename: Xianguang
authors.initials: X
authors.lastname: Nie
authors.affiliation: Key Laboratory of Food Science and Engineering, Harbin University of Commerce, 1 Xuehai Street, 150028, Harbin, Heilongjiang, China.
authors.forename: Min
authors.initials: M
authors.lastname: Qu
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 830011, Urumqi, Xinjiang, China.
authors.forename: Zilong
authors.initials: Z
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China.
authors.forename: Huimin
authors.initials: H
authors.lastname: Zhao
authors.affiliation: Key Laboratory of Biogeography and Bioresource in Arid Land, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, 830011, Urumqi, Xinjiang, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Huo
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China.
authors.forename: Shengnan
authors.initials: S
authors.lastname: Liu
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China.
authors.forename: Bing
authors.initials: B
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, 26 Hexing Road, 150040, Harbin, China.
authors.forename: Yucheng
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000040:Abscisic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects / Q000235:genetics*; D017360:Arabidopsis / Q000166:cytology / Q000187:drug effects / Q000235:genetics* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000378:metabolism*; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D017343:Genes, Plant; D008969:Molecular Sequence Data; D059372:Nucleotide Motifs / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis; D009997:Osmotic Pressure / Q000187:drug effects; D030821:Plants, Genetically Modified; D011392:Proline / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D021381:Protein Transport / Q000187:drug effects; D017382:Reactive Oxygen Species / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects / Q000235:genetics*; D015534:Trans-Activators / Q000378:metabolism
chemical_list: D000040:Abscisic Acid; D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D011392:Proline; D017382:Reactive Oxygen Species; D015534:Trans-Activators; C000621578:bHLH112 protein, Arabidopsis
keywords: Arabidopsis thaliana; AtbHLH112; GCG-box motif; abiotic stress; transcriptional regulation