Characterization of transgenic Arabidopsis plants overexpressing GR-RBP4 under high salinity, dehydration, or cold stress.
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.
Kwak
Kyung Jin
KJ
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.
Kim
Yeon Ok
YO
Kang
Hunseung
H
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*
D029681:Arabidopsis Proteins; D009696:Nucleic Acids; D016601:RNA-Binding Proteins; C506809:glycine-rich RNA-binding protein 4, Arabidopsis; D014867:Water; D012965:Sodium Chloride