Nucleotide diversity patterns at the DREB1 transcriptional factor gene in the genome donor species of wheat (Triticum aestivum L)

Abstract

Bread wheat (AABBDD) originated from the diploid progenitor <i>Triticum urartu</i> (AA), a relative of <i>Aegilops speltoides</i> (BB), and <i>Ae. tauschii</i> (DD). The <i>DREB</i>1 transcriptional factor plays key regulatory role in low-temperature tolerance. The modern breeding strategies resulted in serious decrease of the agricultural biodiversity, which led to a loss of elite genes underlying abiotic stress tolerance in crops. However, knowledge of this gene’s natural diversity is largely unknown in the genome donor species of wheat. We characterized the dehydration response element binding protein 1 (<i>DREB</i>1) gene-diversity pattern in <i>Ae. speltoides, Ae. tauschii, T. monococcum and T. urartu</i>. The highest nucleotide diversity value was detected in <i>Ae. speltoides</i>, followed by <i>Ae. tauschii</i> and <i>T. monococcum</i>. The lowest nucleotide diversity value was observed in <i>T. urartu,</i>. Nucleotide diversity and haplotype data might suggest no reduction of nucleotide diversity during <i>T. monococcum</i> domestication. Alignment of the 68 <i>DREB</i>1 sequences found a large-size (70 bp) insertion/deletion in the accession PI486264 of <i>Ae. speltoides</i>, which was different from the copy of sequences from other accessions of <i>Ae. speltoides</i>, suggesting a likely existence of two different ancestral <i>Ae. speltoides</i> forms. Implication of sequences variation of <i>Ae. speltoides</i> on origination of B genome in wheat was discussed.