Frequent numerical and structural chromosome changes in early generations of synthetic hexaploid wheat

Genome ◽  
2021 ◽  
Author(s):  
Siyu Zhang ◽  
Pei Du ◽  
Xueying Lu ◽  
Jiaxin Fang ◽  
Jiaqi Wang ◽  
...  
Keyword(s):  
Hexaploid Wheat ◽  
Aegilops Tauschii ◽  
Tetraploid Wheat ◽  
Snp Markers ◽  
Synthetic Hexaploid Wheat ◽  
Chromosome Variation ◽  
Metaphase Chromosomes ◽  
Wheat Evolution ◽  
Significant Difference ◽  
Synthetic Hexaploid

Modern hexaploid wheat (Triticum aestivum L.; AABBDD) evolved from a hybrid of tetraploid wheat (closely related to Triticum turgidum L. ssp. durum (Desf.) Husn., AABB) and goatgrass (Aegilops tauschii Coss., DD). Variations in chromosome structure and ploidy played important roles in wheat evolution. How these variations occurred and their role in expanding the genetic diversity in modern wheat is mostly unknown. Synthetic hexaploid wheat (SHW) can be used to investigate chromosome variation that occurs during the early generations of existence. SHW lines derived by crossing durum wheat ‘Langdon’ with twelve Ae. tauschii accessions were analyzed using oligonucelotide probe multiplex fluorescence in situ hybridization (FISH) to metaphase chromosomes and SNP markers. Cluster analysis based on SNP markers categorized them into three groups. Among 702 plants from the S8 and S9 generations, 415 (59.12%) carried chromosome variations involving all 21 chromosomes but with different frequencies for each chromosome and sub-genome. Total chromosome variation frequencies varied between lines, but there was no significant difference among the three groups. The non-random chromosome variations in SHW lines detected in this research may be an indication that similar variations occurred in the early stages of wheat polyploidization and played important roles in wheat evolution.

scholarly journals Polyploidization enhancing genetic recombination of the ancestral diploid genome in the evolution of hexaploid wheat

2020 ◽  
Author(s):  
Hongshen Wan ◽  
Jun Li ◽  
Shengwei Ma ◽  
Qin Wang ◽  
Xinguo Zhu ◽  
...  
Keyword(s):  
Hexaploid Wheat ◽  
Genetic Recombination ◽  
Aegilops Tauschii ◽  
Tetraploid Wheat ◽  
Synthetic Hexaploid Wheat ◽  
Evolutionary Potential ◽  
D Genome ◽  
Diploid Genome ◽  
Synthetic Hexaploid ◽  
The Impact

AbstractAllopolyploidy increases its evolutionary potential by fixing heterosis and the advantage of gene redundancy. Allelic combinations generated from genetic recombination potentially provide many variations to the selection pools for evolution. May there be any relationship between allopolyploidization and genetic recombination? To study the impact of polyploidy on genetic recombination, we selected wheat as a model and simulated its evolution pathway of allopolyploidy by developing synthetic hexaploid wheat. The change of homologous chromosome recombination were investigated on their diploid DD and tetraploid AABB genomes after their allohexaploidization, respectively. The genetic recombination of the ancestral diploid genome of Aegilops tauschii was enhanced significantly more than 2 folds after their hexaploidization. Hexaploidization enhancing genetic recombination of the ancestral diploid D genome was firstly reported to be a new way to increase evolutionary potential of wheat, which is beneficial for wheat to conquer their narrow origination of D genome, quickly spread and make it a major crop of the world. Finally, re-synthetizing hexaploid wheat using diverse Ae. tauschii species with tetraploid wheat can be considered as a pleiotropic strategy to speed adaptive evolution of bread wheat in breeding processes by increasing both gene allele types and genetic recombination variations.

scholarly journals Ozone Tolerance Found in Aegilops Tauschii and Primary Synthetic Hexaploid Wheat

Plants ◽  
2019 ◽  
Vol 8 (7) ◽  
pp. 195 ◽  
Author(s):  
Brewster ◽  
Hayes ◽  
Fenner
Keyword(s):  
Hexaploid Wheat ◽  
Aegilops Tauschii ◽  
Grain Weight ◽  
Synthetic Hexaploid Wheat ◽  
Shoot Biomass ◽  
Seed Head ◽  
Modern Wheat ◽  
Synthetic Hexaploid ◽  
1000 Grain Weight ◽  
Ozone Levels

Modern wheat cultivars are increasingly sensitive to ground level ozone, with 7–10% mean yield reductions in the northern hemisphere. In this study, three of the genome donors of bread wheat, Triticum urartu (AA), T. dicoccoides (AABB), and Aegilops tauschii (DD) along with a modern wheat cultivar (T. aestivum ‘Skyfall’), a 1970s cultivar (T. aestivum ‘Maris Dove’), and a line of primary Synthetic Hexaploid Wheat were grown in 6 L pots of sandy loam soil in solardomes (Bangor, North Wales) and exposed to low (30 ppb), medium (55 ppb), and high (110 ppb) levels of ozone over 3 months. Measurements were made at harvest of shoot biomass and grain yield. Ae. tauschii appeared ozone tolerant with no significant effects of ozone on shoot biomass, seed head biomass, or 1000 grain + husk weight even under high ozone levels. In comparison, T. urartu had a significant reduction in 1000 grain + husk weight, especially under high ozone (−26%). The older cultivar, ‘Maris Dove’, had a significant reduction in seed head biomass (−9%) and 1000 grain weight (−11%) but was less sensitive than the more recent cultivar ‘Skyfall’, which had a highly significant reduction in its seed head biomass (−21%) and 1000 grain weight (−27%) under high ozone. Notably, the line of primary Synthetic Hexaploid Wheat was ozone tolerant, with no effect on total seed head biomass (−1%) and only a 5% reduction in 1000 grain weight under high ozone levels. The potential use of synthetic wheat in breeding ozone tolerant wheat is discussed.

scholarly journals Empirical verification of heterogeneous DNA fragments generated from wheat genome-specific SSR primers

2008 ◽  
Vol 88 (6) ◽  
pp. 1065-1071 ◽  
Author(s):  
Qijiao Chen ◽  
Lianquan Zhang ◽  
Zhongwei Yuan ◽  
Zehong Yan ◽  
Youliang Zheng ◽  
...  
Keyword(s):  
Common Wheat ◽  
Hexaploid Wheat ◽  
Chinese Spring ◽  
Triticum Turgidum ◽  
Sequence Data ◽  
Aegilops Tauschii ◽  
Single Locus ◽  
Synthetic Hexaploid Wheat ◽  
D Genome ◽  
Synthetic Hexaploid

Due to the high polymorphisms between synthetic hexaploid wheat (SHW) and common wheat, SHW has been widely used in genetic studies. The transferability of simple sequence repeats (SSR) among common wheat and its donor species, Triticum turgidum and Aegilops tauschii, and their SHW suggested the possibility that some SSRs, specific for a single locus in common wheat, might appear in two or more loci in SHWs. This is an important genetic issue when using synthetic hexaploid wheat population and SSR for mapping. However, it is largely ignored and never empirically well verified. The present study addressed this issue by using the well-studied SSR marker Xgwm261 as an example. The Xgwm261 produced a 192 bp fragment specific to chromosome 2D in common wheat Chinese Spring, but generated a 176 bp fragment in the D genome of Ae. tauschii AS60. Chromosomal location and DNA sequence data revealed that the176 bp fragment also donated by 2B chromosome of durum wheat Langdon. These results indicated that although a single 176 bp fragment was appeared in synthetic hexaploid wheat Syn-SAU-5 between Langdon and AS60, the fragment contained two different loci, one from chromosome 2D of AS60 and the other from 2B of Langdon which were confirmed by the segregating analysis of SSR Xgwm261 in 185 plants from a F2 population between Syn-SAU-5 and Chinese Spring. If Xgwm261 in Syn-SAU-5 was considered as a single locus in genetic analysis, distorted segregation or incorrect conclusions would be yielded. A proposed strategy to avoid this problem is to include SHW’s parental T. turgidum and Ae. tauschii in SSR analysis as control for polymorphism detection. Key words: Synthetic hexaploid wheat, microsatellite, segregation distortion, Xgwm261, transferability

scholarly journals Allopolyploidization Enhances Genetic Recombination of the Ancestral Diploid Genome in the Evolution of Wheat

2020 ◽  
Author(s):  
Hongshen Wan ◽  
Jun Li ◽  
Shengwei Ma ◽  
Fan Yang ◽  
Liang Chai ◽  
...  
Keyword(s):  
Hexaploid Wheat ◽  
Genetic Recombination ◽  
Recombination Frequency ◽  
Aegilops Tauschii ◽  
Synthetic Hexaploid Wheat ◽  
Evolutionary Potential ◽  
D Genome ◽  
Diploid Genome ◽  
Synthetic Hexaploid ◽  
The Impact

Abstract Background: Genetic recombination produces different allelic combinations potentially, providing new variations to the selection pools for domestication. Allopolyploidization increases evolutionary potential of the hexaploid common wheat by taking its advantages of heterosis and gene redundancy. May there be any relationship between allopolyploidization and genetic recombination? To study the impact of allopolyploidization on genetic recombination in different ancestral genomes of wheat, we generated synthetic hexaploid wheat by crossed tetraploid Triticum turgidum with diploid Aegilops tauschii to simulate its evolutionary hexaploidization process. Results: Using Wheat Breeder’s Genotyping Array, the genotypes of F2 individuals were investigated in both tetraploid (A1A1B1B1 x A2A2B2B2) and their synthetic hexaploid wheat derived populations (A1A1B1B1DD x A2A2B2B2DD). And the genotypes of the diploid population (D1D1 x D2D2) and their synthetic hexaploid wheat derived population (AABBD1D1 x AABBD2D2) were obtained with DArT-Seq™ technology. Based on genotypes of F2 populations, the genetic recombination frequency of homologous chromosome were consequently calculated in ancestral tetraploid AABB (4x), diploid DD (2x) and their synthetic hexaploid AABBDD (6x) plants, respectively. The recombination frequency of the ancestral diploid genome DD from Aegilops tauschii was found enhanced significantly more than 2 folds after their hexaploidization, while no significant changes was found in their ancestral tetraploid genome AABB via hexaploidization.Conclusions: Allopolyploidization enhancing genetic recombination of the ancestral diploid genome is found to increase the evolutionary potential of wheat, which is beneficial for wheat to conquer their narrow origination of D genome, quickly spread and make it a major crop of the world.

scholarly journals Mapping QTLs for enhancing early biomass derived from Aegilops tauschii in synthetic hexaploid wheat

PLoS ONE ◽  
2020 ◽  
Vol 15 (6) ◽  
pp. e0234882
Author(s):  
Yumin Yang ◽  
Hongshen Wan ◽  
Fan Yang ◽  
Chun Xiao ◽  
Jun Li ◽  
...  
Keyword(s):  
Hexaploid Wheat ◽  
Aegilops Tauschii ◽  
Synthetic Hexaploid Wheat ◽  
Synthetic Hexaploid

scholarly journals Development and Characterization of Synthetic Hexaploid Wheat for Improving the Resistance of Common Wheat to Leaf Rust and Heat Stress

Agronomy ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 18
Author(s):  
Hai An Truong ◽  
Hyeri Lee ◽  
Masahiro Kishii ◽  
Suk Whan Hong ◽  
Hojoung Lee
Keyword(s):  
Heat Stress ◽  
Leaf Rust ◽  
Common Wheat ◽  
Hexaploid Wheat ◽  
Aegilops Tauschii ◽  
Synthetic Hexaploid Wheat ◽  
Synthetic Hexaploid ◽  
Shock Proteins ◽  
Wheat Lines

Synthetic hexaploid wheat (SHW) is a valuable resource for breeding because it possesses more desirable traits, such as better yield and abiotic and biotic stress tolerance than common wheat. In this study, our group developed a SHW line, named ‘SynDT’, which has markedly better characteristics than Korean bread wheat ‘Keumkang’. The SynDT line is thermotolerant as it rapidly expresses heat shock proteins under heat stress. In addition, this line exhibits resistance to leaf rust by inducing the expression of antifungal enzymes, mainly chitinase, along with the rapid and high expression of pathogen-related genes. Moreover, it possesses the favorable traits of its parent wheat lines Triticum durum #24 and Aegilops tauschii #52. Therefore, the SynDT wheat line can be used as a breeding material for improving local common wheat cultivars.

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