Cold-inducible zinc finger-containing glycine-rich RNA-binding protein contributes to the enhancement of freezing tolerance in Arabidopsis thaliana.
Glycine-rich RNA-binding proteins (GR-RBPs) have been implicated to play roles in post-transcriptional regulation of gene expression in plants under various stress conditions, but the functional roles of GR-RBPs under stress conditions remain to be verified. Here, we examine the biological roles of a GR-RBP, designated atRZ-1a, in Arabidopsis thaliana under stress conditions. atRZ-1a was expressed ubiquitously in various Arabidopsis organs including stems, roots, leaves, flowers, and siliques. The transcript level of atRZ-1a increased markedly by cold stress, whereas its expression was marginally downregulated by drought stress or abscisic acid treatment. Germination and seedling growth of the loss-of-function mutants were retarded remarkably compared with those of the wild type under cold stress. In contrast, the transgenic Arabidopsis plants that overexpress atRZ-1a displayed earlier germination and better seedling growth than the wild type under cold stress. Moreover, the atRZ-1a-overexpressing transgenic Arabidopsis plants were more freezing tolerant than the wild-type plants. Heterologous expression of atRZ-1a in Escherichia coli demonstrated that the E. coli cells expressing atRZ-1a displayed much higher growth rate than the non-transformed cells after cold shock. These results provide evidence that atRZ-1a affects seed germination and seedling growth under low temperature and plays a role in the enhancement of freezing tolerance in Arabidopsis plants.
Kim
Yeon-Ok
YO
Division of Applied Plant Science and Agricultural Plant Stress Research Center, College of Agriculture and Life Sciences, Chonnam National University, Gwangju 500-757, Korea.
Kim
Jin Sun
JS
Kang
Hunseung
H
D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000502:physiology*; D003080:Cold Temperature; D004926:Escherichia coli / Q000235:genetics; D005615:Freezing; D018506:Gene Expression Regulation, Plant / Q000502:physiology*; D018525:Germination / Q000502:physiology; D030781:Organisms, Genetically Modified; D011485:Protein Binding; D016601:RNA-Binding Proteins / Q000502:physiology*
D029681:Arabidopsis Proteins; D016601:RNA-Binding Proteins; C503765:RZ-1a protein, Arabidopsis