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, DREB2, DREB6 and Wdreb2 are isolated from wheat AK58, yet they belong to different types of DREB transcription factors. Under osmotic stress, the transcript expression of DREB2, DREB6 and Wdreb2 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 DREB2 and Wdreb2 are slightly methylated, but DREB6’s promoter is moderately methylated. Compared with the control, the level of promoter methylation in Wdreb2 is significantly lower under osmotic stress and is also lower at CG site in DREB2, yet is significantly higher at CHG and CHH sites in DREB2, which is also found at a CHG site in DREB6. The status of promoter methylation in DREB2, DREB6 and Wdreb2 also undergoes significant changes under osmotic stress; further analysis showed that promoter methylation of Wdreb2 is negatively correlated with their expression. Therefore, the results of this research suggest the different functions of DREB2, DREB6 and Wdreb2 in response to osmotic stress and demonstrate the effects of promoter methylation on the expression regulation of Wdreb2.

Response of wheat DREB transcription factor to drought stress based on DNA methylation

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. Although 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.

Response of wheat DREB transcription factor to drought stress based on DNA methylation

Background: The growth and development of wheat are seriously influenced by drought stress, and the research on drought resistance mechanism of wheat is very important. 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, their CDS sequences were composed of 732 bp, 837 bp or 1035 bp, respectively, and one 712 bp intron was found in DREB6. Although AP2/EREBP domain of DREB2, DREB6 and Wdreb2 had 73.25% identity, they belong to different types of DREB transcription factor, and the expression of Wdreb2 was significantly higher, yet was the lowest in DREB2. Under drought stress, the expression of DREB2, DREB6 and Wdreb2 could be induced, but had different trends along with the increase of stress time, and their expression had tissue specificity, was obviously higher in leaf. Promoter of DREB2, DREB6 and Wdreb2 in leaf was further studied, some elements related to adverse stress were found, and the promoter of DREB2 and Wdreb2 was slightly methylated, but DREB6 promoter was moderately methylated. Compared with the control, the level of promoter methylation in DREB2 and DREB6 decreased as stressed for 2 h, then increased along with the increase of stress time, which was opposite in Wdreb2 promoter, the status of promoter methylation in DREB2, DREB6 and Wdreb2 also had significant change under drought stress. Further analysis showed that promoter methylation of DREB6 and Wdreb2 was negatively correlated with their expression, especially was significant in Wdreb2. Conclusions: DREB2, DREB6 and Wdreb2 might function differently in response to drought stress, and promoter methylation had more significant effects on gene expression of Wdreb2 and DREB6.

Response of wheat DREB transcription factor to drought stress based on DNA methylation

Background: The growth and development of wheat are seriously influenced by drought stress, and the research on drought resistance mechanism of wheat is very important. 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, their CDS sequences were composed of 732 bp, 837 bp or 1035 bp, respectively, and one 712 bp intron was found in DREB6. Although AP2/EREBP domain of DREB2, DREB6 and Wdreb2 had 73.25% identity, they belong to different types of DREB transcription factor, and the expression of Wdreb2 was significantly higher, yet was the lowest in DREB2. Under drought stress, the expression of DREB2, DREB6 and Wdreb2 could be induced, but had different trends along with the increase of stress time, and their expression had tissue specificity, was obviously higher in leaf. Promoter of DREB2, DREB6 and Wdreb2 in leaf was further studied, some elements related to adverse stress were found, and the promoter of DREB2 and Wdreb2 was slightly methylated, but DREB6 promoter was moderately methylated. Compared with the control, the level of promoter methylation in DREB2 and DREB6 decreased as stressed for 2 h, then increased along with the increase of stress time, which was opposite in Wdreb2 promoter, the status of promoter methylation in DREB2, DREB6 and Wdreb2 also had significant change under drought stress. Further analysis showed that promoter methylation of DREB6 and Wdreb2 was negatively correlated with their expression, especially was significant in Wdreb2. Conclusions: DREB2, DREB6 and Wdreb2 might function differently in response to drought stress, and promoter methylation had more significant effects on gene expression of Wdreb2 and DREB6.