Drought inducible OsDhn1 promoter is activated by OsDREB1A and OsDREB1D

In order to understand the stress-responsive mechanism controlling OsDhn1 gene, promoter analysis of OsDhn1 gene was conducted. First, a 1.5 kb-long promoter region of OsDhn1 was isolated and characterized by β-glucuronidase (GUS) analysis. GUS assay of OsDhn1::gus plants showed that the GUS activity in the leaves was induced by drought stress but not by wound, cold, salt, or ABA treatment. Second, transactivation assay revealed that OsDhn1 promoter is activated by OsDREB1A or OsDREB1D as well as CBF1 but not by OsDREB1B or OsDREB1C. Taken together, these suggest that the drought-inducible OsDhn1 gene is regulated by abiotic stress signaling pathway involving CBF/DREB.