Phylotranscriptomic Analyses Resolve Evolutionary History of Eremopyrum (Triticeae; Poaceae)

Disentangling the phylogenetic relationship of polyploid species is essential for understanding how such polyploid species evolved following their origin. To investigate the speciation and evolutionary history ofEremopyrum, we analyzed 36 transcriptomes from 9 polyploid accessions ofEremopyrumand 27 diploid taxa representing 12 basic genomes in Triticeae. Phylogenetic reconstruction, divergence time, and introgression event demonstrated that (1)EremopyrumandAgropyronshared a common ancestor; (2)Eremopyrumhas undergone ongoing evolutionary diversification since its origin in Late Miocene; (3) the diploidE. triticeumandE. distanswere the genome donors of the tetraploid species ofEremopyrum; (4) bothEremopyrumandAgropyroncontribute to the nonmonophyletic origin of tetraploidE. orientalevia introgression events. Our results shed new light on our understanding of the diversity and ecological adaptation of the species inEremopyrum.