title: Characterization of a wheat heme oxygenase-1 gene and its responses to different abiotic stresses.
abstract: In animals and recently in plants, heme oxygenase-1 (HO1) has been found to confer protection against a variety of oxidant-induced cell and tissue injuries. In this study, a wheat (Triticum aestivum) HO1 gene TaHO1 was cloned and sequenced. It encodes a polypeptide of 31.7 kD with a putative N-terminal plastid transit peptide. The amino acid sequence of TaHO1 was found to be 78% similar to that of maize HO1. Phylogenetic analysis revealed that TaHO1 clusters together with the HO1-like sequences in plants. The purified recombinant TaHO1 protein expressed in Escherichia coli was active in the conversion of heme to biliverdin IXa (BV), and showed that the V(max) was 8.8 U·mg(-1) protein with an apparent K(m) value for hemin of 3.04 μM. The optimum Tm and pH were 35 °C and 7.4, respectively. The result of subcellular localization of TaHO1 showed that the putative transit peptide was sufficient for green fluorescent protein (GFP) to localize in chloroplast and implied that TaHO1 gene product is at least localized in the chloroplast. Moreover, we found that TaHO1 mRNA could be differentially induced by the well-known nitric oxide (NO) donor sodium nitroprusside (SNP), gibberellin acid (GA), abscisic acid (ABA), hydrogen peroxide (H(2)O(2)) and NaCl treatments. Therefore, the results suggested that TaHO1 might play an important role in abiotic stress responses.
authors.affiliation: College of Life Sciences, Cooperative Demonstration Laboratory of Centrifuge Technique, Nanjing Agricultural University, Nanjing 210095, China; E-Mails:  2009116134@njau.edu.cn  (D.X.);  2010216030@njau.edu.cn  (Q.J.);  2008216036@njau.edu.cn  (Y.X.);  webmasterone@sina.com  (Y.-h.L.)  2010116133@njau.edu.cn  (Y.-t.L.).
authors.forename: Dao-Kun
authors.initials: DK
authors.lastname: Xu
authors.forename: Qi-Jiang
authors.initials: QJ
authors.lastname: Jin
authors.forename: Yan-Jie
authors.initials: YJ
authors.lastname: Xie
authors.forename: Ya-Hui
authors.initials: YH
authors.lastname: Liu
authors.forename: Yu-Ting
authors.initials: YT
authors.lastname: Lin
authors.forename: Wen-Biao
authors.initials: WB
authors.lastname: Shen
authors.forename: Yi-Jun
authors.initials: YJ
authors.lastname: Zhou
mesh_terms: D000040:Abscisic Acid / Q000378:metabolism; D000595:Amino Acid Sequence; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D006418:Heme / Q000378:metabolism; D051547:Heme Oxygenase-1 / Q000235:genetics* / Q000378:metabolism; D006427:Hemin / Q000378:metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D008969:Molecular Sequence Data; D005810:Multigene Family; D009569:Nitric Oxide / Q000378:metabolism; D009599:Nitroprusside / Q000378:metabolism; D010802:Phylogeny; D016415:Sequence Alignment; D013312:Stress, Physiological; D014908:Triticum / Q000201:enzymology / Q000235:genetics*; D003313:Zea mays / Q000235:genetics
chemical_list: D009599:Nitroprusside; D009569:Nitric Oxide; D006418:Heme; D000040:Abscisic Acid; D006427:Hemin; D006861:Hydrogen Peroxide; D051547:Heme Oxygenase-1