Phylogeny and genetic diversity of D-genome species of Aegilops and Triticum (Triticeae, Poaceae) from Iran based on microsatellites, ITS, and trnL-F

Abstract

Cereal species of the grass tribe Triticeae are economically important and provide staple food for large parts of the human population. The Fertile Crescent of Southwest Asia harbors high genetic and morphological diversity of these species. In this study, we analyzed genetic diversity and phylogenetic relationships among D genome-bearing species of the wheat relatives of the genus Aegilops from Iran and adjacent areas using allelic diversity at 25 nuclear microsatellite loci, nuclear rDNA ITS, and chloroplast trnL-F sequences. Our analyses revealed high microsatellite diversity in Aegilops tauschii and the D genomes of Triticum aestivum and Ae. ventricosa, low genetic diversity in Ae. cylindrica, two different Ae. tauschii gene pools, and a close relationship among Ae. crassa, Ae. juvenalis, and Ae. vavilovii. In the latter species group, cloned sequences revealed high diversity at the ITS region, while in most other polyploids, homogenization of the ITS region towards one parental type seems to have taken place. The chloroplast genealogy of the trnL-F haplotypes showed close relationships within the D genome Aegilops species and T. aestivum, the presence of shared haplotypes in up to three species, and up to three different haplotypes within single species, and indicates chloroplast capture from an unidentified species in Ae. markgrafii. The ITS phylogeny revealed Triticum as monophyletic and Aegilops as monophyletic when Amblyopyrum muticum is included.