Isolation and Functional Characterization of ZmDBP2 Encoding a Dehydration-Responsive Element-Binding Protein in Zea mays

Dehydration-responsive element-binding proteins (DREBs) play vital regulatory roles in abiotic stress responses in plants. A member of the DREB gene family in maize, isolated and designated as Zea mays dehydration-responsive element-binding protein 2 (ZmDBP2), encoded a putative protein of 343 amino acids with a conserved DNA-binding domain. Transcription of the ZmDBP2 gene was highly induced by drought and moderately induced by salt and exogenous abscisic acid. Isolation of the ZmDBP2 promoter revealed some cis-acting elements responding to stresses. The ZmDBP2 protein activated C-repeat/dehydration responsive element-containing genes under normal growth conditions in transgenic Arabidopsis plants and accumulated throughout the cell. These results indicated that ZmDBP2 possibly interacts with another transcription factor(s) before acting via the nucleus. Overexpression of ZmDBP2 improved drought stress tolerance in transgenic Arabidopsis plants. Our data showed that ZmDBP2 could be a new member of DREB transcription factor family involved in activation of downstream genes in response to environmental stresses.