The SsDREB Transcription Factor from the Succulent Halophyte Suaeda salsa Enhances Abiotic Stress Tolerance in Transgenic Tobacco.

Xu Zhang,Xiaoxue Liu,Xiue Wang,Lei Wu,Guihong Yu,Hongxiang Ma

doi:10.1155/2015/875497

Abstract

Dehydration-responsive element-binding (DREB) transcription factor (TF) plays a key role for abiotic stress tolerance in plants. In this study, a novel cDNA encoding DREB transcription factor, designated SsDREB, was isolated from succulent halophyte Suaeda salsa. This protein was classified in the A-6 group of DREB subfamily based on multiple sequence alignments and phylogenetic characterization. Yeast one-hybrid assays showed that SsDREB protein specifically binds to the DRE sequence and could activate the expression of reporter genes in yeast, suggesting that the SsDREB protein was a CBF/DREB transcription factor. Real-time RT-PCR showed that SsDREB was significantly induced under salinity and drought stress. Overexpression of SsDREB cDNA in transgenic tobacco plants exhibited an improved salt and drought stress tolerance in comparison to the nontransformed controls. The transgenic plants revealed better growth, higher chlorophyll content, and net photosynthesis rate, as well as higher level of proline and soluble sugars. The semiquantitative PCR of transgenics showed higher expression of stress-responsive genes. These data suggest that the SsDREB transcription factor is involved in the regulation of salt stress tolerance in tobacco by the activation of different downstream gene expression.

Highlights

The abiotic stresses like salinity, drought, and low and high temperature negatively affect plant growth and productivity [1]
PpDBF1 from Physcomitrella patens was induced under salt, dehydration as well as cold stress [19], while SbDREB2A from Salicornia brachiata was induced by NaCl, drought, and heat stress [20]
Phylogenic tree analysis of Dehydration-responsive element-binding (DREB) proteins showed that SsDREB, together with Arabidopsis RAP2.4, ZmDREB1, OsDBF1, and ChDREB2, is attributable to the DREB (A-6) lineage (Figure 1(b))

Summary

Introduction

The abiotic stresses like salinity, drought, and low and high temperature negatively affect plant growth and productivity [1]. They are major limiting factors for sustainable food production as they reduce yields by more than 50% in crop plants [2]. To overcome these limitations, plants have generated mechanisms to trigger a cascade of events leading to changes in gene expression and subsequently to biochemical physiological modifications that can enhance their stress tolerance [3]. The Dehydrationresponsive element-binding proteins (DREBs) are members of the APETALA2/ethylene-responsive element-binding factor (AP2/ERF) family of transcription factors in the promoters of stress-inducible genes [6]

Methods

Results

Conclusion