Exploring the genetic diversity of the DRF1 gene in durum wheat and its wild relatives

A drought-related gene belonging to the Dehydration Responsive Element Binding protein (DREB) family has been reported and characterized in durum wheat. Unlike other DREB-homologous genes, it consists of four exons and three introns and produces three transcripts by an alternative splicing mechanism. The gene sequence was analysed in a number of varieties/lines/accessions of durum wheat, triticale and in wheat genome donors, Aegilops speltoides, A. tauschii and Triticum urartu, in order to evaluate the variability and to detect other interesting molecular features. Herewith, some results are presented. In the exon 1, a single sequence repeat codifying for a stretch of alanine residues variable in length (from 3 to 7), was identified. A novel non-autonomous transposon was identified, encompassing the intron1-intron3 region and this was characterized in detail. Part of the exon 4, containing the APetala2 (AP2) domain, responsible for DNA recognition and binding, was isolated and sequenced in a collection of Aegilops species and A. speltoides accessions from the Fertile Crescent, a region characterized by a high wheat biodiversity. Although the 338 bp-long analysed sequences did not reveal substantial differences in the polymorphic patterns, using a geographic subdivision with three clusters (east, centre and west), they completely separated Aegilops from the A. speltoides genus.