Characterization of the ZmDBP4 gene encoding a CRT/DRE-binding protein responsive to drought and cold stress in maize

C-repeat/dehydration-responsive element binding factors (CBF/DREBs) play a vital regulatory role in abiotic stress responses in plants. We isolated the ZmDBP4 gene, a member of the A-1 subgroup of the CBF/DREB subfamily, from maize seedlings. A ZmDBP4::hGFP fusion protein was found to localize into the nucleus upon introduction into epidermal onion cells. As a trans-acting factor, the ZmDBP4 protein activated CRT/DRE-containing genes under normal growth conditions in transgenic Arabidopsis plants. ZmDBP4 transcription was highly activated by cold and moderately by drought in ABA-independent manner. Isolation of the ZmDBP4 promoter revealed some cis-acting elements responding to stresses. Overexpression of ZmDBP4 improved drought and cold-stress tolerance in transgenic Arabidopsis plants. Our results suggested that ZmDBP4 produces a functional factor that may play a regulatory role in abiotic stress response.