Abstract
Dehydration-responsive element-binding factor 2 (DREB2) belongs to the C-repeat-binding factor (CBF)/DREB subfamily of proteins. In this study, a 2,245 bp PsDREB2 promoter fragment was isolated from the genome of Paeonia suffruticosa. The fragment was rich in A/T bases and contained TATA box sequences, abscisic acid (ABA)-response elements, and other cis-elements, such as MYB and CAAT box. The promoter was fused with the β-glucuronidase (GUS) reporter gene to generate an expression vector. Arabidopsis thaliana was transformed with a flower dipping method. Gus activity in different tissues and organs of transgenic plants was determined via histochemical staining and quantified via GUS fluorescence. The activity of promoter regulatory elements in transgenic plants under drought, low-temperature, high-salt, and ABA stresses was analyzed. The results showed that the PsDREB2 gene promoter was expressed in the roots, stems, leaves, flowers, and silique pods but not in the seeds of transgenic Arabidopsis. Furthermore, the promoter was induced by drought, low temperature, high salt, and ABA. Hence, the PsDREB2 promoter is tissue- and stress-specific and can be used in the genetic engineering of novel peony cultivars in the future.
Highlights
Abiotic stresses, such as drought, cold, salt, and low temperature, were the major limiting factors affecting plant growth and development
The results of the bioinformatics analysis revealed that the PsDREB2 promoter contains numerous cis-acting elements (Table 2)
Many stress-responsive elements were predicted, such as the anaerobic-responsive element (ARE) involved in anaerobic induction, the MYB recognition sites involved in drought and abscisic acid (ABA) signals, and the MYC recognition site involved in drought, ABA and cold signals
Summary
Abiotic stresses, such as drought, cold, salt, and low temperature, were the major limiting factors affecting plant growth and development. Plants developed a series of adverse response mechanisms. Dehydration-responsive element-binding (DREB) proteins are a class of important signal transduction and transcription factors. A transcription factor binds to the cis-acting element of dehydration-responsive element(DRE)/C-repeat (CRT), which is located upstream of the gene promoter, and activates the related stress-induced genes to enhance the resistance of plants (Liu et al, 1998; Yamaguchi-Shinozaki & Shinozaki, 1994). Since the discovery of the DREB gene in Arabidopsis thaliana, its overexpression in transgenic plants has effectively improved plant tolerance toward multiple stresses (Liu et al, 1998). The cloning, functional identification, and mechanistic analysis of the DREB gene have become hotspots of plant
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