Isolation and characterization of DREB gene in ancestral diploid wheat species from a wheat domestication center
The dehydration responsive element (DRE)-binding proteins (DREB) play a role in the signaling network that activates many abiotic stress-responsive genes. We isolated and molecularly characterized the DREB gene from ancestral diploid wheat species growing in Azerbaijan and native to this region. This territory is included in a region that is considered the center of origin of cultivated wheat. One-week-old seedlings of Triticum urartu (Au), Aegilops speltoides (B) and Ae. tauschii (D) were used for genomic DNA extraction. Gene-specific primer pairs were applied forisolation of the DREB gene. The amplification products were purified using a gel extraction kit and sequenced. Data analysis was performed using FGENESH, BLAST, INTERPROSCAN, SMART, MAFFT, ExPASy, ProteinPredict, and PSIPRED tools. Ensembl Plants and NCBI were used as integrative resources. Numerous SNPs and nine microindels were detected in the partial target sequence of the DREB gene in Ae. speltoides. Nonsynonymous SNPs were determined in T. urartu (1 transition and 5 transversions), and Ae. tauschii (2 transitions and 2 transversions). Analysis of amino acid sequences encoded by the putative DREB genes revealed a conserved AP2/ERF domain, with two conserved functional amino acids (14th valine and 19th glutamic acid) that play crucial roles in the recognition of the DNA-binding sequence and two tryptophan rings that determine the geometry of the GCC-box binding domain. Nuclear localization signal and conserved Ser/Thr-rich region were observed in the corresponding amino acid sequences. One α-helix and three β-sheets were detected in the secondary structure of the AP2 domain. The isolated sequences of DREB gene from T. urartu and Ae. tauschii were confirmed and registered in NCBI with Accession Numbers MZ935739 and MZ935740. Identification of the DREB gene in wheat progenitors and its characterization is important for evaluating their genomic material for possible use to enhance the diversity of wheat cultivated under stress conditions.