Motif X (CACACGTGGG) and motif Y (CACACGTATC) of theDcECP31 promoter have different functions in the ABA-response pathway

We have identified two important elements in the DcECP31 promoter, the ABA-responsive element (ABRE)-like motif X (CACACGTGGG), and motif Y (CACACGTATC), which are sufficient for embryo-specific and ABA-inducible promoter activities. Using gain-of-function analysis, we demonstrated that motifs X and Y are necessary and sufficient to confer ABA-responsiveness upon a heterologous, truncated CaMV minimum promoter. Motif-exchange experiments were carried out to determine whether these motifs exerted similar effects on the DcECP31 promoter. The results suggest that motif X functions as an enhancer-like element and that motif Y participates in ABA-responsiveness.