Generation and exploitation of EST-derived SSR markers for assaying molecular diversity in durum wheat populations

Abstract

Durum wheat [Triticum turgidum L. subsp. turgidum convar. durum (Desf.) MK] is an important cereal crop economically and nutritionally in the Central Asia and Caucasian, West Asia, and North Africa (CWANA) regions. Durum landraces and improved lines are largely grown in this region. Its genetic diversity has been studied using different molecular markers. The increasing availability of expressed sequence tags (ESTs) in wheat (Triticum aestivum) and related cereals provides a valuable resource of non-anonymous DNA markers to study durum diversity. In this study, a set of 517,319 Triticum aestivum EST sequences was employed for the identification of wheat simple sequence repeats called microsatellites (W-eSSRs) with the help of a PERL5 script called MISA. In comparison, barley microsatellites (B-eSSRs) have been used to exploit their transferability to durum wheat. Newly developed W-eSSR markers were probed on the 115 recombinant inbred lines (RIL) of the International Triticeae Mapping Initiative (ITMI) population (Opata 85 x Synthetic 7984). The polymorphic eSSRs were mapped. To examine the potential of the two types of eSSRs markers, 12 W-eSSR markers and 13 B-eSSR markers were used to fingerprint 153 wheat genotypes. Our results indicate that: (1) B-eSSRs show a high level of transferability to wheat, (2) the developed W-eSSRs are significantly polymorphic than those derived from genomic regions, (3) new W-eSSRs were identified and integrated in the ITMI genetic linkage map and, (4) B-eSSR and W-eSSRs are providing additional markers for comparative mapping following gene introgressions from wild species and carrying out evolutionary studies.