Response of Wheat DREB Transcription Factor to Osmotic Stress Based on DNA Methylation.

Dehydration-responsive element-binding protein (DREB) plays an important role in response to osmotic stress. In this study, , and are isolated from wheat AK58, yet they belong to different types of DREB transcription factors. Under osmotic stress, the transcript expression of , and has tissue specificity and is generally higher in leaves, but their expression trends are different along with the increase of osmotic stress. Furthermore, some elements related to stresses are found in their promoters, promoters of and are slightly methylated, but 's promoter is moderately methylated. Compared with the control, the level of promoter methylation in is significantly lower under osmotic stress and is also lower at CG site in , yet is significantly higher at CHG and CHH sites in , which is also found at a CHG site in . The status of promoter methylation in , and also undergoes significant changes under osmotic stress; further analysis showed that promoter methylation of is negatively correlated with their expression. Therefore, the results of this research suggest the different functions of , and in response to osmotic stress and demonstrate the effects of promoter methylation on the expression regulation of .