Isolation of genes similar to DREB1/CBF from sweet cherry (Prunus avium L.)

The C-repeat (CRT) dehydration responsive element (CRT/DRE) is a cis-acting DNA element, which stimulates transcription in response to low temperature and drought stress. Recently, the DREB1/CBF (regulatory factor that binds to the CRT/DRE elements and promotes expression of multiple low-temperature-induced genes resulting in cold-acclimation) has been identified in Arabidopsis thaliana L. We have isolated a genomic clone from Prunus avium L. (sweet cherry) that was predicted to include three DREB1/CBF-like genes. Two (D2A and D2B) of the genes were deduced to have a complete open reading frame (ORF) and the other (D2Ctr: truncated D2C) was deduced to have an incomplete ORF. Each putative protein had an EREBP/AP2 DNA binding domain motif and a potential nuclear localization signal in the N-terminal region. Furthermore, the D2A and the D2B proteins had an acidic C-terminal region. The D2A and the D2B proteins were found to be 53 and 53.5% identical to DREB1B/CBF1, respectively, However, the EREBP/AP2 conserved domain of the three D2 proteins showed a high identity (74-79%) with that of each DREB1/CBF. In addition, the TATA-box and G-box sequences, and MYB- and MYC-recognition sites were predicted along with in the 5' other conserved sequences of all three genes. The expression of the D2 genes was found to be induced by low temperature in P. avium.