Journal Article

GmDREB2A;2, a Canonical DEHYDRATION-RESPONSIVE ELEMENT-BINDING PROTEIN2-Type Transcription Factor in Soybean, Is Posttranslationally Regulated and Mediates Dehydration-Responsive Element-Dependent Gene Expression

Todaka, Daisuke, Moriwaki, Takashi, Kidokoro, Satoshi, Osakabe, Yuriko, Mizoi, Junya, Kusakabe, Kazuya, Ohori, Teppei, Maruyama, Kyonoshin, Yamaguchi-Shinozaki, Kazuko, Shinozaki, Kazuo

2013

Overview

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 PROTEIN2 (DREB2) group includes transcription factors that contribute to drought and heat stress tolerance by activating transcription through the cis-element dehydration-responsive element (DRE) in response to these stress stimuli. Two modes of regulation, transcriptional and posttranslational, 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 by low temperature. GmDREB2A;2 exhibited a high transactivation activity via DRE and has a serine/threonine-rich region, which corresponds to a negative regulatory domain of DREB2A that is involved in its posttranslational 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 serine/threonine-rich region in both Arabidopsis and soybean protoplasts, suggestive of a conserved regulatory mechanism that involves the recognition of serine/threonine-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.

• Publisher: American Society of Plant Biologists
• Subject: Adaptation, Physiological / Amino Acid Sequence / Arabidopsis - genetics / Arabidopsis - growth & development / Arabidopsis - metabolism / Arabidopsis Proteins - genetics / Arabidopsis Proteins - metabolism / Arabidopsis thaliana / Biological and medical sciences / Cell Nucleus - genetics / Cell Nucleus - metabolism / Dehydration / Drought / Droughts / Fundamental and applied biological sciences. Psychology / gene activation / Gene expression / Gene Expression Regulation, Plant / Genes / Genes, Plant / Germination / Glycine max / Glycine max - genetics / Glycine max - growth & development / Glycine max - metabolism / heat / heat stress / heat tolerance / heterologous gene expression / Molecular Sequence Data / Oligonucleotide Array Sequence Analysis / Phenotype / Phylogeny / Plant physiology and development / Plants / Plants, Genetically Modified - genetics / Plants, Genetically Modified - growth & development / Plants, Genetically Modified - metabolism / Promoter Regions, Genetic / Protein Processing, Post-Translational / Protein Stability / Proteins / Protoplasts / Sequence Homology / Serine - metabolism / SIGNALING AND RESPONSE / Soybean Proteins - genetics / Soybean Proteins - metabolism / Soybeans / stress response / stress tolerance / Stress, Physiological / temperature / Threonine - metabolism / transcription (genetics) / Transcription factors / Transcription Factors - genetics / Transcription Factors - metabolism / Transcriptional Activation / Transgenic plants