title: Origin and Reticulate Evolutionary Process of Wheatgrass Elymus trachycaulus (Triticeae: Poaceae).
abstract: To study origin and evolutionary dynamics of tetraploid Elymus trachycaulus that has been cytologically defined as containing StH genomes, thirteen accessions of E. trachycaulus were analyzed using two low-copy nuclear gene Pepc (phosphoenolpyruvate carboxylase) and Rpb2 (the second largest subunit of RNA polymerase II), and one chloroplast region trnL-trnF (spacer between the tRNA Leu (UAA) gene and the tRNA-Phe (GAA) gene). Our chloroplast data indicated that Pseudoroegneria (St genome) was the maternal donor of E. trachycaulus. Rpb2 data indicated that the St genome in E. trachycaulus was originated from either P. strigosa, P. stipifolia, P. spicata or P. geniculate. The Hordeum (H genome)-like sequences of E. trachycaulus are polyphyletic in the Pepc tree, suggesting that the H genome in E. trachycaulus was contributed by multiple sources, whether due to multiple origins or introgression resulting from subsequent hybridization. Failure to recovering St copy of Pepc sequence in most accessions of E. trachycaulus might be caused by genome convergent evolution in allopolyploids. Multiple copies of H-like Pepc sequence from each accession with relative large deletions and insertions might be caused by either instability of Pepc sequence in H- genome or incomplete concerted evolution. Our results highlighted complex evolutionary history of E. trachycaulus.
authors.affiliation: College of Agronomy, Anhui Agricultural University, Hefei, Anhui, China.
authors.forename: Hongwei
authors.initials: H
authors.lastname: Zuo
authors.affiliation: College of Agronomy, Anhui Agricultural University, Hefei, Anhui, China.
authors.forename: Panpan
authors.initials: P
authors.lastname: Wu
authors.affiliation: College of Agronomy, Anhui Agricultural University, Hefei, Anhui, China.
authors.forename: Dexiang
authors.initials: D
authors.lastname: Wu
authors.affiliation: College of Agronomy, Anhui Agricultural University, Hefei, Anhui, China; Biology Department, Saint Mary's University, Halifax, Nova Scotia, Canada.
authors.forename: Genlou
authors.initials: G
authors.lastname: Sun
mesh_terms: D031702:Agropyron / Q000235:genetics; D001483:Base Sequence; D005075:Biological Evolution; D002736:Chloroplasts / Q000235:genetics*; D018742:DNA, Chloroplast / Q000235:genetics; D021901:DNA, Intergenic / Q000235:genetics; D031749:Elymus / Q000235:genetics*; D019143:Evolution, Molecular; D014644:Genetic Variation / Q000235:genetics; D018745:Genome, Plant; D001467:Hordeum / Q000235:genetics*; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012319:RNA Polymerase II / Q000235:genetics*; D017422:Sequence Analysis, DNA
chemical_list: D018742:DNA, Chloroplast; D021901:DNA, Intergenic; C069767:phosphoenolpyruvate carboxylase kinase; D017346:Protein Serine-Threonine Kinases; D012319:RNA Polymerase II