title: Molecular cloning and characterization of an S-adenosylmethionine synthetase gene from Chorispora bungeana.
abstract: S-adenosylmethionine synthetase (SAMS) catalyzes the formation of S-adenosylmethionine (SAM) which is a molecule essential for polyamines and ethylene biosynthesis, methylation modifications of protein, DNA and lipids. SAMS also plays an important role in abiotic stress response. Chorispora bungeana (C. bungeana) is an alpine subnival plant species which possesses strong tolerance to cold stress. Here, we cloned and characterized an S-adenosylmethionine synthetase gene, CbSAMS (C. bungeana S-adenosylmethionine synthetase), from C. bungeana, which encodes a protein of 393 amino acids containing a methionine binding motif GHPDK, an ATP binding motif GAGDQG and a phosphate binding motif GGGAFSGDK. Furthermore, an NES (nuclear export signal) peptide was identified through bioinformatics analysis. To explore the CbSAMS gene expression regulation, we isolated the promoter region of CbSAMS gene 1919bp upstream the ATG start codon, CbSAMSp, and analyzed its cis-acting elements by bioinformatics method. It was revealed that a transcription start site located at 320 bp upstream the ATG start codon and cis-acting elements related to light, ABA, auxin, ethylene, MeJA, low temperature and drought had been found in the CbSAMSp sequence. The gene expression pattern of CbSAMS was then analyzed by TR-qPCR and GUS assay method. The result showed that CbSAMS is expressed in all examined tissues including callus, roots, petioles, leaves, and flowers with a significant higher expression level in roots and flowers. Furthermore, the expression level of CbSAMS was induced by low temperature, ethylene and NaCl. Subcellular localization revealed that CbSAMS was located in the cytoplasm and nucleus but has a significant higher level in the nucleus. These results indicated a potential role of CbSAMS in abiotic stresses and plant growth in C. bungeana.
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: dingcc11@lzu.edu.cn.
authors.forename: Chenchen
authors.initials: C
authors.lastname: Ding
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: chent11@lzu.edu.cn.
authors.forename: Tao
authors.initials: T
authors.lastname: Chen
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: yy86525@126.com.
authors.forename: Yu
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: liush12@lzu.edu.cn.
authors.forename: Sha
authors.initials: S
authors.lastname: Liu
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: happytiger8@163.com.
authors.forename: Kan
authors.initials: K
authors.lastname: Yan
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: yuexiule@lzu.edu.cn.
authors.forename: Xiule
authors.initials: X
authors.lastname: Yue
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: zhanghua@lzu.edu.cn.
authors.forename: Hua
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: xiangy@lzu.edu.cn.
authors.forename: Yun
authors.initials: Y
authors.lastname: Xiang
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: lizhean@lzu.edu.cn.
authors.forename: Lizhe
authors.initials: L
authors.lastname: An
authors.affiliation: Key Laboratory of Arid and Grassland Ecology, School of Life Sciences, Lanzhou University, Lanzhou 730000, China. Electronic address: chenshy@lzu.edu.cn.
authors.forename: Shuyan
authors.initials: S
authors.lastname: Chen
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D001665:Binding Sites; D019607:Brassicaceae / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular / Q000379:methods*; D019295:Computational Biology / Q000379:methods; D035264:Flowers / Q000235:genetics / Q000378:metabolism; D008716:Methionine Adenosyltransferase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D049790:Nuclear Export Signals / Q000235:genetics; D010940:Plant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018517:Plant Roots / Q000235:genetics / Q000378:metabolism; D011401:Promoter Regions, Genetic
chemical_list: D049790:Nuclear Export Signals; D010940:Plant Proteins; D000255:Adenosine Triphosphate; D008716:Methionine Adenosyltransferase
keywords: Chorispora bungeana; Low temperature response; S-adenosylmethionine synthetase