Background: The growth and development of wheat are seriously influenced by drought, dehydration responsive element binding protein (DREB) plays an important role in the response of plant to drought stress, but epigenetic regulation for gene expression of DREB transcription factor is less studied, especially the regulatory role of DNA methylation has not been reported.Results: In this research, DREB2, DREB6 and Wdreb2 were cloned from wheat AK58, and one 712-bp intron was identified in DREB6.

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... though AP2/EREBP domains of DREB2, DREB6 and Wdreb2 showed 73.25% identity, they belong to different types of DREB transcription factor. Under drought stress, different transcript expression patterns of DREB2, DREB6 and Wdreb2 were observed, and their expression had tissue specificity, was obviously higher in leaves. Promoters of DREB2, DREB6 and Wdreb2 were further studied, some elements related to stresses were found, and the promoters of DREB2 and Wdreb2 were slightly methylated, but DREB6 promoter was moderately methylated. Compared with the control, the level of promoter methylation in DREB2 and DREB6 decreased after 2 h stress treatment, and then increased, which was opposite in Wdreb2 promoter, the status of promoter methylation in DREB2, DREB6 and Wdreb2 also had significant changes under drought stress. Further analysis showed that promoter methylation of DREB6 and Wdreb2 was negatively correlated with their expression, especially in Wdreb2. Conclusions: Our data suggest the different functions of DREB2, DREB6 and Wdreb2 in response to drought stress, and demonstrate the strong effects of promoter methylation on the regulation of Wdreb2 and DREB6 gene expression.