Population structure of wild wheat D‐genome progenitor Aegilops tauschii Coss.: implications for intraspecific lineage diversification and evolution of common wheat

Abstract

Aegilops tauschii Coss. is the D-genome progenitor of hexaploid wheat. Aegilops tauschii, a wild diploid species, has a wide natural species range in central Eurasia, spreading from Turkey to western China. Amplified fragment length polymorphism (AFLP) analysis using a total of 122 accessions of Ae. tauschii was conducted to clarify the population structure of this widespread wild wheat species. Phylogenetic and principal component analyses revealed two major lineages in Ae. tauschii. Bayesian population structure analyses based on the AFLP data showed that lineages one (L1) and two (L2) were respectively significantly divided into six and three sublineages. Only four out of the six L1 sublineages were diverged from those of western habitats in the Transcaucasia and northern Iran region to eastern habitats such as Pakistan and Afghanistan. Other sublineages including L2 were distributed to a limited extent in the western region. Subspecies strangulata seemed to be differentiated in one sublineage of L2. Among three major haplogroups (HG7, HG9 and HG16) previously identified in the Ae. tauschii population based on chloroplast variation, HG7 accessions were widely distributed to both L1 and L2, HG9 accessions were restricted to L2, and HG16 accessions belonged to L1, suggesting that HG9 and HG16 were formed from HG7 after divergence of the first two lineages of the nuclear genome. These results on the population structure of Ae. tauschii and the genealogical relationship among Ae. tauschii accessions should provide important agricultural and evolutionary knowledge on genetic resources and conservation of natural genetic diversity.

Differential effects of Aegilops tauschii genotypes on maturing-time in synthetic hexaploid wheats

“…tauschii is widely distributed in Eurasia, ranging from Turkey to China, and shows considerable genetic variation (Dvorak et al 1998, Matsuoka et al 2005, Mizuno et al 2010. The birthplace of hexaploid wheat is believed to lie within the area comprising Transcaucasia and the southern coastal region of the Caspian Sea.…”

Comparative nucleotide sequence analysis of the D genome-specific sequence-tagged-site locus A1 in Triticum aestivum and its implication for the origin of subspecies sphaerococcum

“…It has been proposed that common wheat originated in the region extending from the southwestern Caspian Sea to Transcaucasia (Dvorak 1998, Nakai 1979, Nishikawa et al 1980, Tsunewaki 1966. Although the origin and evolution of common wheat have both been studied extensively (for reviews, see Feldman 2001, Salamini et al 2002, specific details on these aspects remain unresolved (Mizuno et al 2010). Thus, to comprehensively address the origin and evolution of common wheat, this study attempted to clarify the phylogenetic relationships among the common wheat subspecies.…”

“…Nuclear DNA assays, such as restriction fragment length polymorphism (RFLP) markers (Dvorak et al 1998, Tsunewaki andNakamura 1995), random amplified polymorphic DNA (RAPD) markers (Cao et al 1998(Cao et al , 2000, simple sequence repeats (SSR) or microsatellite markers (Lelley et al 2000, Mitrofanova et al 2009, and amplified fragment length polymorphisms (AFLP) (Hirosawa et al 2004, Mizuno et al 2010 have also been employed. The maternal lineage of common wheat has also been studied by plasmon or mitochondrial/chloroplast DNA analysis using mainly RFLP and SSR markers (Hirosawa et al 2004, Mori et al 2008, Tsunewaki 1996.…”

Genetic Characterization of Genetic Resources of <i>Aegilops tauschii</i>, Wheat D Genome Donor, Newly Collected in North Caucasia

“…tauschii has been studied extensively using various techniques, that is, isozyme [11] [12] [13], RFLP [14], chloroplast SSR [15] [16], AFLP [17] [18] and DNA array [19] [20] [21]. Based on RFLP, Dvorak et al (1998) reported that Ae.…”