title: Polyploidy origin of wheatgrass Douglasdeweya wangii (Triticeae, Poaceae): evidence from nuclear ribosomal DNA internal transcribed spacer and chloroplast trnL-F sequences.
abstract: To study hybrid speciation in wheatgrass Douglasdeweya wangii and to investigate the evolutionary pattern of nuclear ribosomal DNA (nrDNA) internal transcribed spacer sequences (ITSs) in allotetraploids, DNA sequence variation of ITSs and chloroplast trnL-F sequences from D. wangii and its putative donors were analyzed. The ITSs revealed that D. wangii had an StP genome composition. Most accessions of D. wangii had one parental ITS copy in their genome, one accession had two parental ITSs. The trnL-F sequences revealed an especially close relationship of Pseudoroegneria to all D. wangii individuals included, and the two accessions of Pseudoroegneria tauri (PI401324 and PI401331) were maternal candidates of the studied D. wangii individuals. Both of ITS and trnL-F trees suggested multiple origins and recurrent hybridization of D. wangii. Thus, the results suggested that: (1) the St and P genome in allotetraploid D. wangii were donated by Pseudoroegneria and Agropyron, respectively;(2) Pseudoroegneria was the maternal donor of D. wangii, and P. tauri 26 (accession PI401324) and P. tauri 27 (accession PI401331) were most likely the potential candidates of maternal donors; (3) D. wangii individuals studied here showed multiple origins and experienced recurrent hybridization; and (4) bidirectional interlocus concerted evolution of ITSs had occurred in most D. wangii accessions, while in one accession concerted evolution among homeologous loci did not occur.
authors.affiliation: Department of Bioengineering and Biotechnology, Qingdao University of Science and Technology, Qingdao, 266042, China. liuquanlan@yahoo.com
authors.forename: Quanlan
authors.initials: Q
authors.lastname: Liu
authors.forename: Bao-Rong
authors.initials: BR
authors.lastname: Lu
authors.forename: Ningning
authors.initials: N
authors.lastname: Zhang
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Ying
authors.initials: Y
authors.lastname: Yu
authors.forename: Hongguang
authors.initials: H
authors.lastname: Wang
authors.forename: Xuebing
authors.initials: X
authors.lastname: Yan
mesh_terms: D001483:Base Sequence; D002467:Cell Nucleus / Q000235:genetics; D003001:Cloning, Molecular; D017124:Conserved Sequence; D018742:DNA, Chloroplast / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D049810:Genetic Speciation; D014644:Genetic Variation; D018745:Genome, Plant; D058889:Molecular Typing; D010802:Phylogeny; D006109:Poaceae / Q000145:classification* / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011123:Polyploidy; D018749:RNA, Plant / Q000235:genetics; D012343:RNA, Transfer / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D018742:DNA, Chloroplast; D021903:DNA, Ribosomal Spacer; D018749:RNA, Plant; D012343:RNA, Transfer