Genome-wide identification and analysis of the DREB genes and their expression profiles under abiotic stresses in Chinese jujube(Ziziphus jujuba Mill.)

CBF/DREB proteins play a critical role in abiotic stress-mediated gene expression and represent attractive regulons for plant breeding programs.However,no study has been conducted for CBF/DREB protein-related genes in jujube(Ziziphus jujuba Mill.).In this study,twenty-five ZjDREB genes were identified and annotated from the jujube(Z.jujuba‘Dongzao’)genome.Detailed analysis,including gene classification,annotation,phylogenetic evaluation,conserved motif determination and expression profiling were performed on all genes.Phylogenetic analysis showed that ZjDREB proteins were divided into five subgroups(A1–A5),but lacking a subgroup A6 corresponding to AtDREBs.The ZjDREB genes were distributed in nine of twelve chromosomes in the genome.Additionally,the expression patterns of the DREB genes under different abiotic stresses were investigated using q RT-PCR.Nineteen ZjDREB genes were down-regulated under low temperature,in contrast six ZjDREB genes(01,03,05,11,23 and 24)were up-regulated.Under drought,salinity and high temperature conditions,expression of ZjDREB03,09,10,14,15,17 and 20 genes were induced and showed similar expression patterns,suggesting that various stress conditions share common elements in the signaling pathway.The results suggest that the family of DREB genes play an important role in abiotic stresses in jujube,and provide a foundation for further functional studies of this important class of transcriptional regulators.