Wound-inducible expression of the OsDof1 gene promoter in a Ds insertion mutant and transgenic plants

The DNA binding with one finger (Dof) proteins are plant-specific transcription factors that contain a particular class of zinc-finger DNA-binding domain. Thirty-different Dof genes are predicted to exist in the rice genome based on in silico analysis. A member of the Dof transcription factor family, Dof1 of rice ( Oryza sativa ), was identified from a dissociation ( Ds ) insertion mutant population. The Ds -tagged rice mutant line osdof1 - Ds was identified from a population of rice tagged with promoterless β - glucuronidase ( GUS ) in T-DNA, and showed wound-responsive GUS expression. Genomic Southern analysis revealed that this mutant line contained a single copy of the Ds gene trap. Four wound-response-like cis -acting elements (PI-II, EIRE, W box, and G box-like elements) were found in the OsDof1 promoter region. To analyze the cis -acting elements, we constructed fusion genes between the OsDof1 promoter and the GUS reporter gene and transformed Arabidopsis and rice plants with these constructs. GUS gene expression was induced in leaf, seed, culm, and flower tissues of the osdof1 - Ds mutant after wounding. Furthermore, histochemical analysis of the OsDof1 promoter :: GUS fusion transgenic plants showed an early response to wounding. In addition, OsDof1 mRNA was induced by pathogen treatment. These results suggest that OsDof1 is a transcriptional activator that regulates gene expression in response to wounding.