The Experts below are selected from a list of 4599 Experts worldwide ranked by ideXlab platform
Yoshihiro Matsuoka - One of the best experts on this subject based on the ideXlab platform.
-
intraspecific lineage divergence and its association with reproductive trait change during species range expansion in central eurasian wild wheat Aegilops tauschii coss poaceae
BMC Evolutionary Biology, 2015Co-Authors: Yoshihiro Matsuoka, Shigeo Takumi, Taihachi KawaharaAbstract:Background How species ranges form in landscapes is a matter of long-standing evolutionary interest. However, little is known about how natural phenotypic variations of ecologically important traits contribute to species range expansion. In this study, we examined the phylogeographic patterns of phenotypic changes in life history (seed production) and phenological (flowering time) traits during the range expansion of Aegilops tauschii Coss. from the Transcaucasus and Middle East to central Asia.
-
Applicability of Aegilops tauschii drought tolerance traits to breeding of hexaploid wheat
Breeding science, 2011Co-Authors: Quahir Sohail, Tomoe Inoue, Hiroyuki Tanaka, Amin Elsadig Eltayeb, Yoshihiro Matsuoka, Hisashi TsujimotoAbstract:Few genes are available to develop drought-tolerant bread wheat (Triticum aestivum L.) cultivars. One way to enhance bread wheat’s genetic diversity would be to take advantage of the diversity of wild species by creating synthetic hexaploid wheat (SW) with the genomic constitution of bread wheat. In this study, we compared the expression of traits encoded at different ploidy levels and evaluated the applicability of Aegilops tauschii drought-related traits using 33 Ae. tauschii accessions along with their corresponding SW lines under well-watered and drought conditions. We found wide variation in Ae. tauschii, and even wider variation in the SW lines. Some SW lines were more drought-tolerant than the standard cultivar Cham 6. Aegilops tauschii from some regions gave better performing SW lines. The traits of Ae. tauschii were not significantly correlated with their corresponding SW lines, indicating that the traits expressed in wild diploid relatives of wheat may not predict the traits that will be expressed in SW lines derived from them. We suggest that, regardless of the adaptability and performance of the Ae. tauschii under drought, production of SW could probably result in genotypes with enhanced trait expression due to gene interactions, and that the traits of the synthetic should be evaluated in hexaploid level.
-
population structure of wild wheat d genome progenitor Aegilops tauschii coss implications for intraspecific lineage diversification and evolution of common wheat
Molecular Ecology, 2010Co-Authors: Nobuyuki Mizuno, Taihachi Kawahara, Yoshihiro Matsuoka, Masanori Yamasaki, Shigeo TakumiAbstract: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.
-
natural variation of morphological traits in wild wheat progenitor Aegilops tauschii coss
Breeding Science, 2009Co-Authors: Shigeo Takumi, Taihachi Kawahara, Emi Nishioka, Haruhiko Morihiro, Yoshihiro MatsuokaAbstract:Aegilops tauschii Coss. (syn Ae. squarrosa L.) is a wild diploid wheat species. It has a wide natural species range in central Eurasia, spreading from northern Syria and Turkey to western China. Ae. tauschii is known as the D genome progenitor of hexaploid bread wheat. The genealogical and geographical structure of variation of morphological traits was analyzed using a diverse array of 205 sample accessions that represented the entire species range. In total, 27 traits, including anther and pistil shape and internode length, were examined in this study. Large-scale natural variation was found for all examined traits. Geographically, significant longitudinal clines were detected for anther size, internode length and spike size and shape. Anthers tended to be small in accessions from the eastern region. Internodes also tended to be short, whereas spikes tended to be long in accessions from the eastern region. Spikelet density per spike tended to be high in the eastern habitats. In the process of west-to-east dispersal, Ae. tauschii underwent extensive morphological, genetic and ecological diversification that produced the variation seen among today’s natural populations.
-
Two major lineages of Aegilops tauschii Coss. revealed by nuclear DNA variation analysis
2008Co-Authors: Shigeo Takumi, Taihachi Kawahara, Nobuyuki Mizuno, Okumura Y, Yoshihiro MatsuokaAbstract:Aegilops tauschii Coss. (syn. Ae. squarrossa L.), a wild diploid self-pollinating goatgrass, is the D genome donor of common wheat. The genome of Aegilops tauschii was brought into common wheat though a natural cross with tetraploid emmer wheat about 8,000 years ago. Habitats of Ae. tauschii are widely distributed from Syria and Turkey to China in Eurasia. The Ae. tauschii population carries large diversity at the molecular levels, considered to be a useful source for common wheat breeding. In fact, some studies have reported higher levels of genetic variability of glutenin subunits and gliadin in Ae. tauschii than in the D genome of common wheat. The subspecific constitution in Ae. tauschii is not clear. Eig categorized two subspecies, tauschii (syn. eusquarrosa Eig) and strangulata based on the spikelet morphology. It has been suggested that ssp. strangulata could have been the D genome donor and that the birthplace of common wheat was most likely to lie within the region comprising Transcaucasia and the south coastal region of Caspian Sea that was the known distribution zone for ssp. strangulata. Thus, the subspecific constitution is an important question to understand the intraspecific differentiation of Ae. tauschii, whereas the two typical forms of ssp. tauschii and strangulata are connected by a continuous range of intermediate forms. Some recent reports also showed difficulty to distinguish the two subspecies based on molecular markers and suggest high gene flow between the subspecies. In this study, we used 62 Ae. tauschii accessions covering the entire species range to study the population structure of Ae. tauschii based on polymorphisms of simple sequence repeat (SSR) and nucleotide variation of several loci. The implications of those findings for the intraspecific differentiation are discussed.
You-liang Zheng - One of the best experts on this subject based on the ideXlab platform.
-
genome wide association study of 29 morphological traits in Aegilops tauschii
Scientific Reports, 2015Co-Authors: Yaxi Liu, Lang Wang, Ji-rui Wang, Yu-ming Wei, Shuangshuang Mao, Kun Liu, You-liang ZhengAbstract:Aegilops tauschii is the D-genome progenitor of hexaploid wheat (Triticum aestivum). It is considered to be an important source of genetic variation for wheat breeding, and its genome is an invaluable reference for wheat genomics. We conducted a genome-wide association study using 7,185 single nucleotide polymorphism (SNP) markers across 322 diverse accessions of Ae. tauschii that were systematically phenotyped for 29 morphological traits in order to identify marker-trait associations and candidate genes, assess genetic diversity, and classify the accessions based on phenotypic data and genotypic comparison. Using the general linear model and mixed linear model, we identified a total of 18 SNPs significantly associated with 10 morphological traits. Systematic search of the flanking sequences of trait-associated SNPs in public databases identified several genes that may be linked to variations in phenotypes. Cluster analysis using phenotypic data grouped accessions into four clusters, while accessions in the same cluster were not from the same Ae. tauschii subspecies or from the same area of origin. This work establishes a fundamental research platform for association studies in Ae. tauschii and also provides useful information for understanding the genetic mechanism of agronomic traits in wheat.
-
Genome-wide association study of phosphorus-deficiency-tolerance traits in Aegilops tauschii
TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik, 2015Co-Authors: Yaxi Liu, Lang Wang, Mei Deng, Ji-rui Wang, Yu-ming Wei, You-liang ZhengAbstract:Key message Using GWAS, 13 significant SNPs distributed on six of the seven Aegilops tauschii chromosomes (all but 5D) were identified, and several candidate P-deficiency-responsive genes were proposed from searches of public databases.
-
Characterization and expression analysis of WOX2 homeodomain transcription factor in Aegilops tauschii
Genetics and molecular biology, 2014Co-Authors: Shan Zhao, Yaxi Liu, Ji-rui Wang, Qian-tao Jiang, Guoyue Chen, You-liang ZhengAbstract:The WUSCHEL (WUS)-related homeobox (WOX) gene family coordinates transcription during the early phases of embryogenesis. In this study, a putative WOX2 homolog was isolated and characterized from Aegilops tauschii, the donor of D genome of Triticum aestivum. The sequence consisted of 2045 bp, and contained an open reading frame (ORF), encoded 322 amino acids. The predicted protein sequence contained a highly conserved homeodomain and the WUS-box domain, which is present in some members of the WOX protein family. The full-length ORF was subcloned into prokaryotic expression vector pET-30a, and an approximately 34-kDa protein was expressed in Escherichia coli BL21 (DE3) cells with IPTG induction. The molecular mass of the expressed protein was identical to that predicted by the cDNA sequence. Phylogenetic analysis suggested that Ae. tauschii WOX2 is closely related to the rice and maize orthologs. Quantitative PCR analysis showed that WOX2 from Ae. tauschii was primarily expressed in the seeds; transcription increased during seed development and declined after the embryos matured, suggesting that WOX2 is associated with embryo development in Ae. tauschii.
-
Aegilops tauschii single nucleotide polymorphisms shed light on the origins of wheat d genome genetic diversity and pinpoint the geographic origin of hexaploid wheat
New Phytologist, 2013Co-Authors: Ji-rui Wang, You-liang Zheng, Zhongxu Chen, Jan DvorakAbstract:Summary Hexaploid wheat (Triticum aestivum, genomes AABBDD) originated by hybridization of tetraploid Triticum turgidum (genomes AABB) with Aegilops tauschii (genomes DD). Genetic relationships between A. tauschii and the wheat D genome are of central importance for the understanding of wheat origin and subsequent evolution. Genetic relationships among 477 A. tauschii and wheat accessions were studied with the A. tauschii 10K Infinium single nucleotide polymorphism (SNP) array. Aegilops tauschii consists of two lineages (designated 1 and 2) having little genetic contact. Each lineage consists of two closely related sublineages. A population within lineage 2 in the southwestern and southern Caspian appears to be the main source of the wheat D genome. Lineage 1 contributed as little as 0.8% of the wheat D genome. Triticum aestivum is subdivided into the western and Far Eastern populations. The Far Eastern population conserved the genetic make-up of the nascent T. aestivum more than the western population. In wheat, diversity is high in chromosomes 1D and 2D and it correlates in all wheat D-genome and A. tauschii chromosomes with recombination rates. Gene flow from A. tauschii was an important source of wheat genetic diversity and shaped its distribution along the D-genome chromosomes.
-
Aegilops tauschii single nucleotide polymorphisms shed light on the origins of wheat D‐genome genetic diversity and pinpoint the geographic origin of hexaploid wheat
The New phytologist, 2013Co-Authors: Ji-rui Wang, Yu-ming Wei, You-liang Zheng, Ming-cheng Luo, Zhongxu Chen, Frank M. You, Jan DvorakAbstract:Summary Hexaploid wheat (Triticum aestivum, genomes AABBDD) originated by hybridization of tetraploid Triticum turgidum (genomes AABB) with Aegilops tauschii (genomes DD). Genetic relationships between A. tauschii and the wheat D genome are of central importance for the understanding of wheat origin and subsequent evolution. Genetic relationships among 477 A. tauschii and wheat accessions were studied with the A. tauschii 10K Infinium single nucleotide polymorphism (SNP) array. Aegilops tauschii consists of two lineages (designated 1 and 2) having little genetic contact. Each lineage consists of two closely related sublineages. A population within lineage 2 in the southwestern and southern Caspian appears to be the main source of the wheat D genome. Lineage 1 contributed as little as 0.8% of the wheat D genome. Triticum aestivum is subdivided into the western and Far Eastern populations. The Far Eastern population conserved the genetic make-up of the nascent T. aestivum more than the western population. In wheat, diversity is high in chromosomes 1D and 2D and it correlates in all wheat D-genome and A. tauschii chromosomes with recombination rates. Gene flow from A. tauschii was an important source of wheat genetic diversity and shaped its distribution along the D-genome chromosomes.
Taihachi Kawahara - One of the best experts on this subject based on the ideXlab platform.
-
intraspecific lineage divergence and its association with reproductive trait change during species range expansion in central eurasian wild wheat Aegilops tauschii coss poaceae
BMC Evolutionary Biology, 2015Co-Authors: Yoshihiro Matsuoka, Shigeo Takumi, Taihachi KawaharaAbstract:Background How species ranges form in landscapes is a matter of long-standing evolutionary interest. However, little is known about how natural phenotypic variations of ecologically important traits contribute to species range expansion. In this study, we examined the phylogeographic patterns of phenotypic changes in life history (seed production) and phenological (flowering time) traits during the range expansion of Aegilops tauschii Coss. from the Transcaucasus and Middle East to central Asia.
-
population structure of wild wheat d genome progenitor Aegilops tauschii coss implications for intraspecific lineage diversification and evolution of common wheat
Molecular Ecology, 2010Co-Authors: Nobuyuki Mizuno, Taihachi Kawahara, Yoshihiro Matsuoka, Masanori Yamasaki, Shigeo TakumiAbstract: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.
-
natural variation of morphological traits in wild wheat progenitor Aegilops tauschii coss
Breeding Science, 2009Co-Authors: Shigeo Takumi, Taihachi Kawahara, Emi Nishioka, Haruhiko Morihiro, Yoshihiro MatsuokaAbstract:Aegilops tauschii Coss. (syn Ae. squarrosa L.) is a wild diploid wheat species. It has a wide natural species range in central Eurasia, spreading from northern Syria and Turkey to western China. Ae. tauschii is known as the D genome progenitor of hexaploid bread wheat. The genealogical and geographical structure of variation of morphological traits was analyzed using a diverse array of 205 sample accessions that represented the entire species range. In total, 27 traits, including anther and pistil shape and internode length, were examined in this study. Large-scale natural variation was found for all examined traits. Geographically, significant longitudinal clines were detected for anther size, internode length and spike size and shape. Anthers tended to be small in accessions from the eastern region. Internodes also tended to be short, whereas spikes tended to be long in accessions from the eastern region. Spikelet density per spike tended to be high in the eastern habitats. In the process of west-to-east dispersal, Ae. tauschii underwent extensive morphological, genetic and ecological diversification that produced the variation seen among today’s natural populations.
-
Two major lineages of Aegilops tauschii Coss. revealed by nuclear DNA variation analysis
2008Co-Authors: Shigeo Takumi, Taihachi Kawahara, Nobuyuki Mizuno, Okumura Y, Yoshihiro MatsuokaAbstract:Aegilops tauschii Coss. (syn. Ae. squarrossa L.), a wild diploid self-pollinating goatgrass, is the D genome donor of common wheat. The genome of Aegilops tauschii was brought into common wheat though a natural cross with tetraploid emmer wheat about 8,000 years ago. Habitats of Ae. tauschii are widely distributed from Syria and Turkey to China in Eurasia. The Ae. tauschii population carries large diversity at the molecular levels, considered to be a useful source for common wheat breeding. In fact, some studies have reported higher levels of genetic variability of glutenin subunits and gliadin in Ae. tauschii than in the D genome of common wheat. The subspecific constitution in Ae. tauschii is not clear. Eig categorized two subspecies, tauschii (syn. eusquarrosa Eig) and strangulata based on the spikelet morphology. It has been suggested that ssp. strangulata could have been the D genome donor and that the birthplace of common wheat was most likely to lie within the region comprising Transcaucasia and the south coastal region of Caspian Sea that was the known distribution zone for ssp. strangulata. Thus, the subspecific constitution is an important question to understand the intraspecific differentiation of Ae. tauschii, whereas the two typical forms of ssp. tauschii and strangulata are connected by a continuous range of intermediate forms. Some recent reports also showed difficulty to distinguish the two subspecies based on molecular markers and suggest high gene flow between the subspecies. In this study, we used 62 Ae. tauschii accessions covering the entire species range to study the population structure of Ae. tauschii based on polymorphisms of simple sequence repeat (SSR) and nucleotide variation of several loci. The implications of those findings for the intraspecific differentiation are discussed.
-
Aegilops tauschii : Genetic Variation in Iran
Genetic Resources and Crop Evolution, 2005Co-Authors: A. Ju . Dudnikov, Taihachi KawaharaAbstract:All the 79 Aegilops tauschii Coss. accessions of Iranian origin from Prof. Kihara’s collection were analyzed electrophoretically. Of 23 enzyme-encoding loci studied, 11 were polymorphic. In Iran Ae. tauschii is presented by ssp. tauschii and ssp. strangulata which distinctly differ genetically, morphologically and ecologically. Variation patterns of low polymorphic locus Aco2 and highly polymorphic Ep are similar in both subspecies. In contrast, variation of Acph1, Ak, Est2, Est5, Got1, Got2, Got3 and Lap is a set of diverse patterns which markedly differ between subspecies and natural regions also, implying that natural selection is involved.
Shigeo Takumi - One of the best experts on this subject based on the ideXlab platform.
-
intraspecific lineage divergence and its association with reproductive trait change during species range expansion in central eurasian wild wheat Aegilops tauschii coss poaceae
BMC Evolutionary Biology, 2015Co-Authors: Yoshihiro Matsuoka, Shigeo Takumi, Taihachi KawaharaAbstract:Background How species ranges form in landscapes is a matter of long-standing evolutionary interest. However, little is known about how natural phenotypic variations of ecologically important traits contribute to species range expansion. In this study, we examined the phylogeographic patterns of phenotypic changes in life history (seed production) and phenological (flowering time) traits during the range expansion of Aegilops tauschii Coss. from the Transcaucasus and Middle East to central Asia.
-
hypersensitive response like reaction is associated with hybrid necrosis in interspecific crosses between tetraploid wheat and Aegilops tauschii coss
PLOS ONE, 2010Co-Authors: Nobuyuki Mizuno, Naoki Hosogi, Pyoyun Park, Shigeo TakumiAbstract:Background Hybrid speciation is classified into homoploid and polyploid based on ploidy level. Common wheat is an allohexaploid species that originated from a naturally occurring interploidy cross between tetraploid wheat and diploid wild wheat Aegilops tauschii Coss. Aegilops tauschii provides wide naturally occurring genetic variation. Sometimes its triploid hybrids with tetraploid wheat show the following four types of hybrid growth abnormalities: types II and III hybrid necrosis, hybrid chlorosis, and severe growth abortion. The growth abnormalities in the triploid hybrids could act as postzygotic hybridization barriers to prevent formation of hexaploid wheat. Methodology/Principal Findings Here, we report on the geographical and phylogenetic distribution of Ae. tauschii accessions inducing the hybrid growth abnormalities and showed that they are widely distributed across growth habitats in Ae. tauschii. Molecular and cytological characterization of the type III necrosis phenotype was performed. The hybrid abnormality causing accessions were widely distributed across growth habitats in Ae. tauschii. Transcriptome analysis showed that a number of defense-related genes such as pathogenesis-related genes were highly up-regulated in the type III necrosis lines. Transmission electron microscope observation revealed that cell death occurred accompanied by generation of reactive oxygen species in leaves undergoing type III necrosis. The reduction of photosynthetic activity occurred prior to the appearance of necrotic symptoms on the leaves exhibiting hybrid necrosis. Conclusions/Significance Taking these results together strongly suggests that an autoimmune response might be triggered by intergenomic incompatibility between the tetraploid wheat and Ae. tauschii genomes in type III necrosis, and that genetically programmed cell death could be regarded as a hypersensitive response-like cell death similar to that observed in Arabidopsis intraspecific and Nicotiana interspecific hybrids. Only Ae. tauschii accessions without such inhibiting factors could be candidates for the D-genome donor for the present hexaploid wheat.
-
population structure of wild wheat d genome progenitor Aegilops tauschii coss implications for intraspecific lineage diversification and evolution of common wheat
Molecular Ecology, 2010Co-Authors: Nobuyuki Mizuno, Taihachi Kawahara, Yoshihiro Matsuoka, Masanori Yamasaki, Shigeo TakumiAbstract: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.
-
natural variation of morphological traits in wild wheat progenitor Aegilops tauschii coss
Breeding Science, 2009Co-Authors: Shigeo Takumi, Taihachi Kawahara, Emi Nishioka, Haruhiko Morihiro, Yoshihiro MatsuokaAbstract:Aegilops tauschii Coss. (syn Ae. squarrosa L.) is a wild diploid wheat species. It has a wide natural species range in central Eurasia, spreading from northern Syria and Turkey to western China. Ae. tauschii is known as the D genome progenitor of hexaploid bread wheat. The genealogical and geographical structure of variation of morphological traits was analyzed using a diverse array of 205 sample accessions that represented the entire species range. In total, 27 traits, including anther and pistil shape and internode length, were examined in this study. Large-scale natural variation was found for all examined traits. Geographically, significant longitudinal clines were detected for anther size, internode length and spike size and shape. Anthers tended to be small in accessions from the eastern region. Internodes also tended to be short, whereas spikes tended to be long in accessions from the eastern region. Spikelet density per spike tended to be high in the eastern habitats. In the process of west-to-east dispersal, Ae. tauschii underwent extensive morphological, genetic and ecological diversification that produced the variation seen among today’s natural populations.
-
Two major lineages of Aegilops tauschii Coss. revealed by nuclear DNA variation analysis
2008Co-Authors: Shigeo Takumi, Taihachi Kawahara, Nobuyuki Mizuno, Okumura Y, Yoshihiro MatsuokaAbstract:Aegilops tauschii Coss. (syn. Ae. squarrossa L.), a wild diploid self-pollinating goatgrass, is the D genome donor of common wheat. The genome of Aegilops tauschii was brought into common wheat though a natural cross with tetraploid emmer wheat about 8,000 years ago. Habitats of Ae. tauschii are widely distributed from Syria and Turkey to China in Eurasia. The Ae. tauschii population carries large diversity at the molecular levels, considered to be a useful source for common wheat breeding. In fact, some studies have reported higher levels of genetic variability of glutenin subunits and gliadin in Ae. tauschii than in the D genome of common wheat. The subspecific constitution in Ae. tauschii is not clear. Eig categorized two subspecies, tauschii (syn. eusquarrosa Eig) and strangulata based on the spikelet morphology. It has been suggested that ssp. strangulata could have been the D genome donor and that the birthplace of common wheat was most likely to lie within the region comprising Transcaucasia and the south coastal region of Caspian Sea that was the known distribution zone for ssp. strangulata. Thus, the subspecific constitution is an important question to understand the intraspecific differentiation of Ae. tauschii, whereas the two typical forms of ssp. tauschii and strangulata are connected by a continuous range of intermediate forms. Some recent reports also showed difficulty to distinguish the two subspecies based on molecular markers and suggest high gene flow between the subspecies. In this study, we used 62 Ae. tauschii accessions covering the entire species range to study the population structure of Ae. tauschii based on polymorphisms of simple sequence repeat (SSR) and nucleotide variation of several loci. The implications of those findings for the intraspecific differentiation are discussed.
Ji-rui Wang - One of the best experts on this subject based on the ideXlab platform.
-
genome wide association study of 29 morphological traits in Aegilops tauschii
Scientific Reports, 2015Co-Authors: Yaxi Liu, Lang Wang, Ji-rui Wang, Yu-ming Wei, Shuangshuang Mao, Kun Liu, You-liang ZhengAbstract:Aegilops tauschii is the D-genome progenitor of hexaploid wheat (Triticum aestivum). It is considered to be an important source of genetic variation for wheat breeding, and its genome is an invaluable reference for wheat genomics. We conducted a genome-wide association study using 7,185 single nucleotide polymorphism (SNP) markers across 322 diverse accessions of Ae. tauschii that were systematically phenotyped for 29 morphological traits in order to identify marker-trait associations and candidate genes, assess genetic diversity, and classify the accessions based on phenotypic data and genotypic comparison. Using the general linear model and mixed linear model, we identified a total of 18 SNPs significantly associated with 10 morphological traits. Systematic search of the flanking sequences of trait-associated SNPs in public databases identified several genes that may be linked to variations in phenotypes. Cluster analysis using phenotypic data grouped accessions into four clusters, while accessions in the same cluster were not from the same Ae. tauschii subspecies or from the same area of origin. This work establishes a fundamental research platform for association studies in Ae. tauschii and also provides useful information for understanding the genetic mechanism of agronomic traits in wheat.
-
Genome-wide association study of phosphorus-deficiency-tolerance traits in Aegilops tauschii
TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik, 2015Co-Authors: Yaxi Liu, Lang Wang, Mei Deng, Ji-rui Wang, Yu-ming Wei, You-liang ZhengAbstract:Key message Using GWAS, 13 significant SNPs distributed on six of the seven Aegilops tauschii chromosomes (all but 5D) were identified, and several candidate P-deficiency-responsive genes were proposed from searches of public databases.
-
Characterization and expression analysis of WOX2 homeodomain transcription factor in Aegilops tauschii
Genetics and molecular biology, 2014Co-Authors: Shan Zhao, Yaxi Liu, Ji-rui Wang, Qian-tao Jiang, Guoyue Chen, You-liang ZhengAbstract:The WUSCHEL (WUS)-related homeobox (WOX) gene family coordinates transcription during the early phases of embryogenesis. In this study, a putative WOX2 homolog was isolated and characterized from Aegilops tauschii, the donor of D genome of Triticum aestivum. The sequence consisted of 2045 bp, and contained an open reading frame (ORF), encoded 322 amino acids. The predicted protein sequence contained a highly conserved homeodomain and the WUS-box domain, which is present in some members of the WOX protein family. The full-length ORF was subcloned into prokaryotic expression vector pET-30a, and an approximately 34-kDa protein was expressed in Escherichia coli BL21 (DE3) cells with IPTG induction. The molecular mass of the expressed protein was identical to that predicted by the cDNA sequence. Phylogenetic analysis suggested that Ae. tauschii WOX2 is closely related to the rice and maize orthologs. Quantitative PCR analysis showed that WOX2 from Ae. tauschii was primarily expressed in the seeds; transcription increased during seed development and declined after the embryos matured, suggesting that WOX2 is associated with embryo development in Ae. tauschii.
-
Aegilops tauschii single nucleotide polymorphisms shed light on the origins of wheat d genome genetic diversity and pinpoint the geographic origin of hexaploid wheat
New Phytologist, 2013Co-Authors: Ji-rui Wang, You-liang Zheng, Zhongxu Chen, Jan DvorakAbstract:Summary Hexaploid wheat (Triticum aestivum, genomes AABBDD) originated by hybridization of tetraploid Triticum turgidum (genomes AABB) with Aegilops tauschii (genomes DD). Genetic relationships between A. tauschii and the wheat D genome are of central importance for the understanding of wheat origin and subsequent evolution. Genetic relationships among 477 A. tauschii and wheat accessions were studied with the A. tauschii 10K Infinium single nucleotide polymorphism (SNP) array. Aegilops tauschii consists of two lineages (designated 1 and 2) having little genetic contact. Each lineage consists of two closely related sublineages. A population within lineage 2 in the southwestern and southern Caspian appears to be the main source of the wheat D genome. Lineage 1 contributed as little as 0.8% of the wheat D genome. Triticum aestivum is subdivided into the western and Far Eastern populations. The Far Eastern population conserved the genetic make-up of the nascent T. aestivum more than the western population. In wheat, diversity is high in chromosomes 1D and 2D and it correlates in all wheat D-genome and A. tauschii chromosomes with recombination rates. Gene flow from A. tauschii was an important source of wheat genetic diversity and shaped its distribution along the D-genome chromosomes.
-
Aegilops tauschii single nucleotide polymorphisms shed light on the origins of wheat D‐genome genetic diversity and pinpoint the geographic origin of hexaploid wheat
The New phytologist, 2013Co-Authors: Ji-rui Wang, Yu-ming Wei, You-liang Zheng, Ming-cheng Luo, Zhongxu Chen, Frank M. You, Jan DvorakAbstract:Summary Hexaploid wheat (Triticum aestivum, genomes AABBDD) originated by hybridization of tetraploid Triticum turgidum (genomes AABB) with Aegilops tauschii (genomes DD). Genetic relationships between A. tauschii and the wheat D genome are of central importance for the understanding of wheat origin and subsequent evolution. Genetic relationships among 477 A. tauschii and wheat accessions were studied with the A. tauschii 10K Infinium single nucleotide polymorphism (SNP) array. Aegilops tauschii consists of two lineages (designated 1 and 2) having little genetic contact. Each lineage consists of two closely related sublineages. A population within lineage 2 in the southwestern and southern Caspian appears to be the main source of the wheat D genome. Lineage 1 contributed as little as 0.8% of the wheat D genome. Triticum aestivum is subdivided into the western and Far Eastern populations. The Far Eastern population conserved the genetic make-up of the nascent T. aestivum more than the western population. In wheat, diversity is high in chromosomes 1D and 2D and it correlates in all wheat D-genome and A. tauschii chromosomes with recombination rates. Gene flow from A. tauschii was an important source of wheat genetic diversity and shaped its distribution along the D-genome chromosomes.
