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.
Keywords: Cis-element; Histochemical staining; PsDREB2; Stress-specific; Transgenic engineering; β-glucuronidase.