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

Abstract

ABSTRACT 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 of Eremopyrum, we analyzed 36 transcriptomes from 9 polyploid accessions of Eremopyrum and 27 diploid taxa representing 12 basic genomes in Triticeae. Phylogenetic reconstruction, divergence time, and introgression event demonstrated that (1) Eremopyrum and Agropyron shared a common ancestor; (2) Eremopyrum has undergone ongoing evolutionary diversification since its origin in Late Miocene; (3) the diploid E. triticeum and E. distans were the genome donors of the tetraploid species of Eremopyrum; (4) both Eremopyrum and Agropyron contribute to the nonmonophyletic origin of tetraploid E. orientale via introgression events. Our results shed new light on our understanding of the diversity and ecological adaptation of the species in Eremopyrum.

Keywords

• Eremopyrum
• hybridization
• introgression
• polyploid
• speciation