title: The chloroplast view of the evolution of polyploid wheat.
abstract: Polyploid wheats comprise four species: Triticum turgidum (AABB genomes) and T. aestivum (AABBDD) in the Emmer lineage, and T. timopheevii (AAGG) and T. zhukovskyi (AAGGA(m) A(m) ) in the Timopheevi lineage. Genetic relationships between chloroplast genomes were studied to trace the evolutionary history of the species. Twenty-five chloroplast genomes were sequenced, and 1127 plant accessions were genotyped, representing 13 Triticum and Aegilops species. The A. speltoides (SS genome) diverged before the divergence of T. urartu (AA), A. tauschii (DD) and the Aegilops species of the Sitopsis section. Aegilops speltoides forms a monophyletic clade with the polyploid Emmer and Timopheevi wheats, which originated within the last 0.7 and 0.4 Myr, respectively. The geographic distribution of chloroplast haplotypes of the wild tetraploid wheats and A. speltoides illustrates the possible geographic origin of the Emmer lineage in the southern Levant and the Timopheevi lineage in northern Iraq. Aegilops speltoides is the closest relative of the diploid donor of the chloroplast (cytoplasm), as well as the B and G genomes to Timopheevi and Emmer lineages. Chloroplast haplotypes were often shared by species or subspecies within major lineages and between the lineages, indicating the contribution of introgression to the evolution and domestication of polyploid wheats.
authors: Department of Molecular Genetics and Cell Biology, University of Chicago, 920 E 58th St, Chicago, IL, 60637, USA.
authors: Piotr
authors: P
authors: Gornicki
authors: Department of Biology and Microbiology, South Dakota State University, 252 North Plain Biostress, Brookings, SD, 57007, USA.
authors: Huilan
authors: H
authors: Zhu
authors: Department of Biology and Microbiology, South Dakota State University, 252 North Plain Biostress, Brookings, SD, 57007, USA.
authors: Junwei
authors: J
authors: Wang
authors: Department of Biology and Microbiology, South Dakota State University, 252 North Plain Biostress, Brookings, SD, 57007, USA.
authors: Ghana S
authors: GS
authors: Challa
authors: Department of Biology and Microbiology, South Dakota State University, 252 North Plain Biostress, Brookings, SD, 57007, USA.
authors: Zhengzhi
authors: Z
authors: Zhang
authors: Wheat Genetics Resource Center, Department of Plant Pathology, Kansas State University, 4024 Throckmorton Hall, Manhattan, KS, 66506, USA.|Biotechnology Section, Faculty of Sciences, King Abdulaziz University, Jeddeh, Saudi Arabia.
authors: Bikram S
authors: BS
authors: Gill
authors: Department of Biology and Microbiology, South Dakota State University, 252 North Plain Biostress, Brookings, SD, 57007, USA.|Department of Plant Science, South Dakota State University, 247 North Plain Biostress, Brookings, SD, 57007, USA.
authors: Wanlong
authors: W
authors: Li
mesh_terms: D005075:Biological Evolution; D002736:Chloroplasts / Q000235:genetics*; D014644:Genetic Variation; D018745:Genome, Plant; D005838:Genotype; D011123:Polyploidy; D014908:Triticum / Q000235:genetics*
keywords: Aegilops; Speltoides; Triticum; chloroplast genome; domestication; molecular evolution; polyploid wheat