Phylogenetic relationships among Leymus and related diploid genera (Triticeae: Poaceae) based on chloroplast trnQ-rps16 sequences

Abstract

To investigate the phylogenetic relationships among Leymus and related diploid genera, the genome donor of Leymus, and the evolutionary history of polyploid Leymus species, chloroplast trnQ-rps16 sequences were analyzed for 36 accessions of Leymus representing 25 species, together with 11 diploid taxa from six monogenomic genera. The phylogenetic analyses (Neighbor-Joining and MJ network) supported three major clades (Ns, St and Xm). Sequence diversity and genealogical analysis suggested that 1) Leymus species from the same areas or neighboring geographic regions are closely related; 2) most of the Eurasian Leymus species are closely related to Psathyrostachys: P. juncea might serve as the Ns genome donor of polyploid Eurasian Leymus species; 3) the Xm genome may originate from ancestral lineages of Pseudoroegneria (St), Lophopyrum (Ee), Australopyrum (W) and Agropyron (P); 4) the trnQ-rps16 sequences of Leymus are evolutionarily distinct, and may clarify parental lineages and phylogenetic relationships in Leymus.