Genome-wide Sequence Identification and Expression Analysis of DREB Transcription Factors in Nicotiana tabacum

DREB transcription factors, with a typical AP2/ERF DNA-binding domain, play a key role in plants' tolerance to environmental stresses. In this study, based on the common tobacco genome database, 68 members of the tobacco DREB gene family were identified according to Arabidopsis thaliana protein sequences. The analyses of physical and chemical properties, phylogenetic tree, gene structures, and tissue expression patterns were performed. The results suggested that the peptide length of different subfamily members was significantly different. Phylogenetic analysis revealed that the tobacco DREB transcription factor family members could be divided into 5 subfamilies, lacking the A6 group from Arabidopsis thaliana. The patterns of protein structures and organization of conserved domains in tobacco were highly conserved within subfamilies based on the phylogenetic results. Transcriptome analysis showed that the expression patterns of DREBs were different in different tissue types and most DREBs have low expression levels in tobacco, although some have higher expression levels after environmental stress treatments. These results provide a very useful reference for cloning and functional analysis of DREB genes in tobacco.