A DREB gene from Limonium bicolor mediates molecular and physiological responses to copper stress in transgenic tobacco.

The DRE-binding (DREB) transcription factors play an important role in regulating stress-related genes. In the present study, a novel DREB gene (LbDREB) from Limonium bicolor was cloned. To characterize the function of DREB in heavy metal stress tolerance, LbDREB-transformed tobacco plants were generated and subjected to CuSO(4) stress. Analysis of the role of LbDREB in tolerance to copper stress in transgenic tobacco showed that overexpression of LbDREB increased the contents of soluble protein and proline, and elevated the ratio of K to Na under CuSO(4) stress. Moreover, overexpression of LbDREB can up-regulate some stress-related genes, including Cu/Zn superoxide dismutase (Cu/Zn SOD), peroxidases (PODs), late embryogenesis abundant (LEA), and lipid transfer proteins (LTP). These results suggest that LbDREB can enhance plant copper tolerance by up-regulating a series of stress-related genes, thereby mediating physiological processes associated with stress tolerance in plants.