Isolation and Characterization of the Cold-Induced Phyllostachys edulis AP2/ERF Family Transcription Factor, peDREB1

The dehydration-responsive element binding (DREB) transcription factor binds to the dehydration-responsive element (DRE), a cis-acting element, and regulates the expression of multiple target genes involved in plant tolerance to drought, salinity, and cold stress. Phyllostachys edulis is one of the most widely cultivated bamboos species, which is adapted for cultivation in warm and wet condition, and is sensitive to cold. However, a DREB homolog gene has not yet been identified in P. edulis. In this paper, we report the characterization of the peDREB1, cloned from cold-induced P. edulis by rapid amplification of cDNA ends (RACE). The characterization of the gene product as a DREB transcription factor is supported the nuclear localization of a transiently expressed green fluorescent protein (GFP) fusion in onion epidermal cells. Furthermore, peDREB1 can activate reporter gene expression, and we show that the protein specifically binds to the conserved DRE element in a yeast one-hybrid assay. Expression analysis shows that peDREB1 transcription levels rapidly accumulate following exposure to cold stress, peaking at 3 h, while only small changes in mRNA expression are observed during abscisic acid, osmotic stress, or salt treatment. Thus, we have identified and characterized the peDREB1 transcription factor. Similar to other APETALA2/ethylene-responsive element-binding proteins (AP2/EREBP) regulators, we report that the peDREB1 homolog is activated in response to environmental factors in tropical plants.