Molecular cloning, expression profiling and trans-activation property studies of a DREB2-like gene from chrysanthemum (Dendranthema vestitum)

Abstract

Dehydration responsive element binding (DREB) proteins are important transcription factors in plant stress response and signal transduction. In this study, a DREB homolog gene, DvDREB2A, was isolated from chrysanthemum (Dendranthema vestitum) by reverse transcriptase-polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends (RACE) methods. It contained an open reading frame (ORF) of 1,471 bp encoding 366 amino acid residues and was classified as a DREB2 subfamily member based on multiple sequence alignment. The predicted protein sequence contained a typical AP2/EREBP DNA-binding domain near the N-terminal region. In yeast one-hybrid analysis DvDREB2A protein was specifically bound to DRE elements (core sequence, A/GCCGAC) and activated the expression of the reporter HIS3 and LacZ. Transient expression experiment suggested that DvDREB2A protein was localized to the nucleus of onion epidermis cells. Quantitative real-time PCR (QRT-PCR) experiments showed that expression level of DvDREB2A was significantly affected by heat, low temperature, drought, abscisic acid (ABA) and high salinity treatments. These results indicated that the DvDREB2A gene is a new member of the DREB transcription factors, which may play an important role in providing tolerance to environmental stresses.