Publications (2)11.24 Total impact
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Article: GmDREB2A;2, a Canonical DREB2-type Transcription Factor in Soybean, Is Post-translationally Regulated and Mediates DRE-dependent Gene Expression.
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ABSTRACT: Soybean (Glycine max) is an important crop around the world. Abiotic stress conditions, such as drought and heat, adversely affect its survival, growth and production. The Dehydration-Responsive Element-Binding protein 2 (DREB2) group includes transcription factors that contribute to drought and heat stress tolerance by activating transcription through the cis-element DRE in response to these stress stimuli. Two modes of regulation, transcriptional and post-translational, are important for the activation of gene expression by DREB2A in Arabidopsis (Arabidopsis thaliana). However, the regulatory system of DREB2 in soybean is not clear. We identified a new soybean DREB2 gene, GmDREB2A;2, that was highly induced not only by dehydration and heat, but also low temperature. GmDREB2A;2 exhibited a high transactivation activity via DRE and has a Ser/Thr-rich region, which corresponds to a negative regulatory domain of DREB2A that is involved in its post-translational regulation, including destabilization. Despite the partial similarity between these sequences, the activity and stability of the GmDREB2A;2 protein were enhanced by removal of the Ser/Thr-rich region in both Arabidopsis and soybean protoplasts, suggestive of a conserved regulatory mechanism that involves the recognition of Ser/Thr-rich sequences with a specific pattern. The heterologous expression of GmDREB2A;2 in Arabidopsis induced DRE-regulated stress-inducible genes and improved stress tolerance. However, there were variations in the growth phenotypes of the transgenic Arabidopsis, the induced genes and their induction ratios between GmDREB2A;2 and DREB2A. Therefore, the basic function and regulatory machinery of DREB2 have been maintained between Arabidopsis and soybean, although differentiation has also occurred.Plant physiology 11/2012; · 6.53 Impact Factor -
Article: An ABRE promoter sequence is involved in osmotic stress-responsive expression of the DREB2A gene, which encodes a transcription factor regulating drought-inducible genes in Arabidopsis.
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ABSTRACT: In plants, osmotic stress-responsive transcriptional regulation depends mainly on two major classes of cis-acting elements found in the promoter regions of stress-inducible genes: ABA-responsive elements (ABREs) and dehydration-responsive elements (DREs). ABRE has been shown to perceive ABA-mediated osmotic stress signals, whereas DRE is known to be involved in an ABA-independent pathway. Previously, we reported that the transcription factor DRE-BINDING PROTEIN 2A (DREB2A) regulates DRE-mediated transcription of target genes under osmotic stress conditions in Arabidopsis (Arabidopsis thaliana). However, the transcriptional regulation of DREB2A itself remains largely uncharacterized. To elucidate the transcriptional mechanism associated with the DREB2A gene under osmotic stress conditions, we generated a series of truncated and base-substituted variants of the DREB2A promoter and evaluated their transcriptional activities individually. We found that both ABRE and coupling element 3 (CE3)-like sequences located approximately -100 bp from the transcriptional initiation site are necessary for the dehydration-responsive expression of DREB2A. Coupling our transient expression analyses with yeast one-hybrid and chromatin immunoprecipitation (ChIP) assays indicated that the ABRE-BINDING PROTEIN 1 (AREB1), AREB2 and ABRE-BINDING FACTOR 3 (ABF3) bZIP transcription factors can bind to and activate the DREB2A promoter in an ABRE-dependent manner. Exogenous ABA application induced only a modest accumulation of the DREB2A transcript when compared with the osmotic stress treatment. However, the osmotic stress-induced DREB2A expression was found to be markedly impaired in several ABA-deficient and ABA-insensitive mutants. These results suggest that in addition to an ABA-independent pathway, the ABA-dependent pathway plays a positive role in the osmotic stress-responsive expression of DREB2A.Plant and Cell Physiology 12/2011; 52(12):2136-46. · 4.70 Impact Factor
