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

Abstract

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 plant response 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 in this study, their CDS sequence was composed of 732bp, 837bp or 1035bp, respectively, one 712bp 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 mildly methylated. Compared with the control, the level of promoter methylation decreased in DREB2 and DREB6 as stressed for 2h, then increased along with the increase of stress time, which was opposite in Wdreb2 promoter, the status of promoter methylation also had significant change under drought stress. Further analysis showed that promoter methylation of DREB6 or 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.

On the prediction of non-CG DNA methylation using machine learning

“…Observe that most of the motifs are for the CG context. Also observe that almost all the motifs for the CG context are in the AP2/EREBP (ethylene-responsive element binding proteins) class, which have been shown to affect DNA methylation in plants ( 55 , 56 ). More specifically, Zhu et al.…”

“…More specifically, Zhu et al. ( 56 ) showed that under drought stress, cytosine methylation is altered in the promoter region of genes containing the AP2/EREBP domain. López et al.…”