title: Characterization of transgenic Arabidopsis plants overexpressing GR-RBP4 under high salinity, dehydration, or cold stress.
abstract: A glycine-rich RNA-binding protein4 (GR-RBP4), one of the eight GR-RBP family members in Arabidopsis thaliana, was investigated for its stress-related expression, nucleic acid-binding property, and functional roles in plants subjected to various stresses including cold, high salinity, and dehydration. Real-time RT-PCR and GUS expression analyses showed that GR-RBP4 was abundantly expressed in young plants, root tips, and flowers, but weakly in mature leaves and stems, implying that GR-RBP4 is highly expressed in actively proliferating organs. The transcript level of GR-RBP4 increased markedly with cold stress, decreased significantly with salt stress, and decreased slightly with dehydration stress. In vitro nucleic acid-binding assays revealed that GR-RBP4 protein binds sequence non-specifically to RNAs and DNAs. Characterization of the transgenic Arabidopsis plants overexpressing GR-RBP4 under the control of the 35S promoter revealed that 35S::GR-RBP4 lines displayed retarded germination compared with the wild type under salt or dehydration stress. Despite the marked up-regulation of GR-RBP4 expression by cold stress, the 35S::GR-RBP4 lines did not show any noticeable changes in cold or freezing tolerance compared with wild-type plants. These results indicate that GR-RBP4 contributes differently to altered germination and seedling growth of Arabidopsis plants under various stress conditions.
authors.affiliation: Division of Applied Plant Science and Agricultural Plant Stress Research Center, College of Agriculture and Life Sciences, Chonnam National University, 300 Youngbong-Dong, Buk-gu, Gwangju 500-757, South Korea.
authors.forename: Kyung Jin
authors.initials: KJ
authors.lastname: Kwak
authors.forename: Yeon Ok
authors.initials: YO
authors.lastname: Kim
authors.forename: Hunseung
authors.initials: H
authors.lastname: Kang
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D003080:Cold Temperature; D003890:Desiccation; D018506:Gene Expression Regulation, Plant; D005810:Multigene Family; D009696:Nucleic Acids / Q000378:metabolism; D030821:Plants, Genetically Modified; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D012965:Sodium Chloride / Q000494:pharmacology*; D014867:Water / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D009696:Nucleic Acids; D016601:RNA-Binding Proteins; C506809:glycine-rich RNA-binding protein 4, Arabidopsis; D014867:Water; D012965:Sodium Chloride