Chromosomal rearrangements in wheat: their types and distribution

Genome ◽  
2007 ◽  
Vol 50 (10) ◽  
pp. 907-926 ◽  
Author(s):  
E. D. Badaeva ◽  
O. S. Dedkova ◽  
G. Gay ◽  
V. A. Pukhalskyi ◽  
A. V. Zelenin ◽  
...  
Keyword(s):  
Hexaploid Wheat ◽  
Chromosomal Rearrangements ◽  
Tetraploid Wheat ◽  
Unknown Origin ◽  
D Genome ◽  
Wheat Varieties ◽  
High Frequencies ◽  
C Banding ◽  
B Genome ◽  
Translocation Breakpoints

Four hundred and sixty polyploid wheat accessions and 39 triticale forms from 37 countries of Europe, Asia, and USA were scored by C-banding for the presence of translocations. Chromosomal rearrangements were detected in 70 of 208 accessions of tetraploid wheat, 69 of 252 accessions of hexaploid wheat, and 3 of 39 triticale forms. Altogether, 58 types of major chromosomal rearrangements were identified in the studied material; they are discussed relative to 11 additional translocation types described by other authors. Six chromosome modifications of unknown origin were also observed. Among all chromosomal aberrations identified in wheat, single translocations were the most frequent type (39), followed by multiple rearrangements (9 types), pericentric inversions (9 types), and paracentric inversions (3 types). According to C-banding analyses, the breakpoints were located at or near the centromere in 60 rearranged chromosomes, while in 52 cases they were in interstitial chromosome regions. In the latter case, translocation breakpoints were often located at the border of C-bands and the euchromatin region or between two adjacent C-bands; some of these regions seem to be translocation “hotspots”. Our results and data published by other authors indicate that the B-genome chromosomes are involved in translocations most frequently, followed by the A- and D-genome chromosomes; individual chromosomes also differ in the frequencies of translocations. Most translocations were detected in 1 or 2 accessions, and only 11 variants showed relatively high frequencies or were detected in wheat varieties of different origins or from different species. High frequencies of some translocations with a very restricted distribution could be due to a “bottleneck effect”. Other types seem to occur independently and their broad distribution can result from selective advantages of rearranged genotypes in diverse environmental conditions. We found significant geographic variation in the spectra and frequencies of translocation in wheat: the highest proportions of rearranged genotypes were found in Central Asia, the Middle East, Northern Africa, and France. A low proportion of aberrant genotypes was characteristic of tetraploid wheat from Transcaucasia and hexaploid wheat from Middle Asia and Eastern Europe.

Molecular characterization and chromosome-specific TRAP-marker development for Langdon durum D-genome disomic substitution lines

Genome ◽  
2006 ◽  
Vol 49 (12) ◽  
pp. 1545-1554 ◽  
Author(s):  
J. Li ◽  
D.L. Klindworth ◽  
F. Shireen ◽  
X. Cai ◽  
J. Hu ◽  
...  
Keyword(s):  
Triticum Turgidum ◽  
Tetraploid Wheat ◽  
Substitution Lines ◽  
Genome Chromosome ◽  
D Genome ◽  
Single Chromosome ◽  
B Genome ◽  
The Individual ◽  
Trap Marker

The aneuploid stocks of durum wheat ( Triticum turgidum L. subsp. durum (Desf.) Husnot) and common wheat ( T. aestivum L.) have been developed mainly in ‘Langdon’ (LDN) and ‘Chinese Spring’ (CS) cultivars, respectively. The LDN-CS D-genome chromosome disomic substitution (LDN-DS) lines, where a pair of CS D-genome chromosomes substitute for a corresponding homoeologous A- or B-genome chromosome pair of LDN, have been widely used to determine the chromosomal locations of genes in tetraploid wheat. The LDN-DS lines were originally developed by crossing CS nulli-tetrasomics with LDN, followed by 6 backcrosses with LDN. They have subsequently been improved with 5 additional backcrosses with LDN. The objectives of this study were to characterize a set of the 14 most recent LDN-DS lines and to develop chromosome-specific markers, using the newly developed TRAP (target region amplification polymorphism)-marker technique. A total of 307 polymorphic DNA fragments were amplified from LDN and CS, and 302 of them were assigned to individual chromosomes. Most of the markers (95.5%) were present on a single chromosome as chromosome-specific markers, but 4.5% of the markers mapped to 2 or more chromosomes. The number of markers per chromosome varied, from a low of 10 (chromosomes 1A and 6D) to a high of 24 (chromosome 3A). There was an average of 16.6, 16.6, and 15.9 markers per chromosome assigned to the A-, B-, and D-genome chromosomes, respectively, suggesting that TRAP markers were detected at a nearly equal frequency on the 3 genomes. A comparison of the source of the expressed sequence tags (ESTs), used to derive the fixed primers, with the chromosomal location of markers revealed that 15.5% of the TRAP markers were located on the same chromosomes as the ESTs used to generate the fixed primers. A fixed primer designed from an EST mapped on a chromosome or a homoeologous group amplified at least 1 fragment specific to that chromosome or group, suggesting that the fixed primers might generate markers from target regions. TRAP-marker analysis verified the retention of at least 13 pairs of A- or B-genome chromosomes from LDN and 1 pair of D-genome chromosomes from CS in each of the LDN-DS lines. The chromosome-specific markers developed in this study provide an identity for each of the chromosomes, and they will facilitate molecular and genetic characterization of the individual chromosomes, including genetic mapping and gene identification.

Hybrid necrosis as a problem in handling hexaploid × tetraploid wheat crosses

1980 ◽  
Vol 94 (2) ◽  
pp. 377-382 ◽  
Author(s):  
R. S. Gregory
Keyword(s):  
Hexaploid Wheat ◽  
Tetraploid Wheat ◽  
Wheat Breeding ◽  
Small Scale ◽  
Hybrid Necrosis ◽  
Agronomic Characters ◽  
Wheat Varieties ◽  
Hybrid Plants ◽  
Plant Breeding Institute ◽  
Selection For

SummaryA tetraploid wheat breeding programme was initiated at the Plant Breeding Institute in 1970. Hexaploid × tetraploid wheat crosses were expected to contribute to the improvement of the tetraploid wheats but severe hybrid necrosis caused the death of the pentaploid Fxhybrid plants in most crosses. The genotypes of tetraploid wheat selections derived from crosses involving Rampton Rivet, a non-carrier of Neu were determined by test crossing to hexaploid wheat varieties which were known to carry the Neim allele. Similarly, hexaploid wheat selections which did not carry Ne2 were identified from crosses involving Maris Ranger by test crossing to durum selections which carried the Nef allele. By the careful choice of one parent, hexaploid x tetraploid wheat crosses were then made which avoided the hybrid necrosis problem. Segregation of the Ne% gene was as expected but selection for agronomic characters appeared to favour the retention of the dominant allele of the Ne1gene. Nevertheless, test crossing on a relatively small scale still identified many non-carriers.

scholarly journals Conservation and trans-regulation of histone modification in the A and B subgenomes of polyploid wheat during domestication and ploidy transition

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Zhenling Lv ◽  
Zijuan Li ◽  
Meiyue Wang ◽  
Fei Zhao ◽  
Wenjie Zhang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Histone Modification ◽  
Hexaploid Wheat ◽  
Epigenetic Modification ◽  
Expression Profiles ◽  
Tetraploid Wheat ◽  
Gene Expression Profiles ◽  
Great Majority ◽  
D Genome ◽  
Polyploid Wheat

AbstractBackgroundPolyploidy has played a prominent role in the evolution of plants and many other eukaryotic lineages. However, how polyploid genomes adapt to the abrupt presence of two or more sets of chromosomes via genome regulation remains poorly understood. Here, we analyzed genome-wide histone modification and gene expression profiles in relation to domestication and ploidy transition in the A and B subgenomes of polyploid wheat.ResultsWe found that epigenetic modification patterns by two typical euchromatin histone markers, H3K4me3 and H3K27me3, for the great majority of homoeologous triad genes in A and B subgenomes were highly conserved between wild and domesticated tetraploid wheats and remained stable in the process of ploidy transitions from hexaploid to extracted tetraploid and then back to resynthesized hexaploid. However, a subset of genes was differentially modified during tetraploid and hexaploid wheat domestication and in response to ploidy transitions, and these genes were enriched for particular gene ontology (GO) terms. The extracted tetraploid wheat manifested higher overall histone modification levels than its hexaploid donor, and which were reversible and restored to normal levels in the resynthesized hexaploid. Further, while H3K4me3 marks were distally distributed along each chromosome and significantly correlated with subgenome expression as expected, H3K27me3 marks showed only a weak distal bias and did not show a significant correlation with gene expression.ConclusionsOur results reveal overall high stability of histone modification patterns in the A and B subgenomes of polyploid wheat during domestication and in the process of ploidy transitions. However, modification levels of a subset of functionally relevant genes in the A and B genomes weretrans-regulated by the D genome in hexaploid wheat.

scholarly journals Novel fluorescent sequence-related amplified polymorphism(FSRAP) markers for the construction of a genetic linkage map of wheat(Triticum aestivum L.)

Genetika ◽  
2017 ◽  
Vol 49 (3) ◽  
pp. 1081-1093 ◽  
Author(s):  
Lingbo Zhao ◽  
Zhang Li ◽  
Jipeng Qu ◽  
Yan Yu ◽  
Lu Lu ◽  
...  
Keyword(s):  
Genetic Linkage Map ◽  
Average Distance ◽  
Triticum Aestivum L ◽  
Genetic Maps ◽  
The Novel ◽  
Linkage Groups ◽  
D Genome ◽  
Wheat Varieties ◽  
B Genome ◽  
A Genome

Novel fluorescent sequence-related amplified polymorphism (FSRAP) markers were developed based on the SRAP molecular marker. Then, the FSRAP markers were used to construct the genetic map of a wheat (Triticum aestivumL.) recombinant inbred line population derived from a Chuanmai 42?Chuannong 16 cross. Reproducibility and polymorphism tests indicated that the FSRAP markers have repeatability and better reflect the polymorphism of wheat varieties compared with SRAP markers. A total of 430 polymorphic loci between Chuanmai 42 and Chuannong 16 were detected with 189 FSRAP primer combinations. A total of 281 FSARP markers and 39 SSR markers re classified into 20 linkage groups. The maps spanned a total length of 2499.3cM with an average distance of 7.81cM between markers. A total of 201 markers were mapped on the B genome and covered a distance of 1013cM. On the A genome, 84 markers were mapped and covered a distance of 849.6cM. On the D genome, however, only 35 markers were mapped and covered a distance of 636.7cM. No FSRAP markers were distributed on the 7D chromosome. The results of the present study revealed that the novel FSRAP markers can be used to generate dense, uniform genetic maps of wheat.

scholarly journals Chromosome banding patterns and the origin of the B genome in wheat

1974 ◽  
Vol 24 (1) ◽  
pp. 103-108 ◽  
Author(s):  
A. T. Natarajan ◽  
N. P. Sarma
Keyword(s):  
Hexaploid Wheat ◽  
Chromosome Banding ◽  
Tetraploid Wheat ◽  
Aegilops Speltoides ◽  
Banding Patterns ◽  
B Genome ◽  
Genome Donors

SUMMARYThe distribution of heterochromatic regions in the chromosomes of diploid, tetraploid and hexaploid wheat shows that the B genome possesses characteristic large blocks. Though analyses of probable B genome donors indicate that Aegilops speltoides has a pattern of distribution of heterochromatin nearest to the B genome chromosomes, a polyphyletic origin of tetraploid wheat seems more plausible.

Triticum (Aegilops) tauschii in the natural and artificial synthesis of hexaploid wheat

2008 ◽  
Vol 59 (5) ◽  
pp. 475 ◽  
Author(s):  
G. M. Halloran ◽  
F. C. Ogbonnaya ◽  
E. S. Lagudah
Keyword(s):  
Genetic Variation ◽  
Hexaploid Wheat ◽  
Gene Pool ◽  
Growth Habit ◽  
Tetraploid Wheat ◽  
Systematic Evaluation ◽  
Gene Pools ◽  
Bread Making ◽  
D Genome ◽  
Wheat Improvement

An account is given of the possible time(s) and place(s) of the origin of hexaploid wheat from natural hybridisation between Triticum tauschii (Ae. tauschii) and both wild and cultivated forms of tetraploid wheat. A recapitulation is presented of the likely genotypic and phenotypic status of the newly arisen natural hexaploid and the likely path of hybridisation from whence it arose. Recent substantial contributions of T. tauschii to wheat improvement indicate the likelihood that introgession en masse from T. tauschii has not occurred throughout its natural and agricultural associations with wheat. This has been substantiated in comparative studies revealing higher levels of genetic variation in T. tauschii compared with the D genome of hexaploid wheat. A case is made for a widening of the concept of the gene pool of T. tauschii for wheat improvement and the notion of a secondary gene pool is proposed to include variation in T. tauschii as it occurs in several polyploid forms of ‘grass Triticum’. The likely differentiation of growth habit forms, conditioned by vernalisation (i.e. vrn) genes, in hexaploid wheat synthesis, including the interaction of these genes in hexaploid wheat, is discussed. It is speculated that growth habit differentiation was of significance to the hexaploid’s yield contribution and survival in tetraploid-hexaploid mixtures (likely to be a common constitution of wheat crops of early agriculture), and in the Neolithic spread of agriculture to the higher latitude, and colder environments of NW Europe and central Asia. The significance of the contribution of T. tauschii to the unique milling and bread-making properties of hexaploid wheat is discussed in the light of Roman discernment of its closer fulfilment of the requirements of leavened bread-making compared with tetraploid wheat. The significance of the contribution of T. tauschii to the evolution of wheat appears to have been much delayed (by ~6500 years) in that hexaploid wheat did not receive singular attention and cultivation until during the Roman era, from whence it gradually rose in popularity to eventually achieve its current pre-eminent status. Continuing systematic evaluation of genetic variation in both the primary and secondary gene pools of T. tauschii for wheat improvement, using both conventional and genetic analysis and contemporary genomic tools, is advocated. The latter approach is particularly important for quantitative traits in the light of wide divergence in plant phenotype of their representatives from that of hexaploid wheat.

scholarly journals Dynamic and reversible DNA methylation changes induced by genome separation and merger of polyploid wheat

BMC Biology ◽  
2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Jingya Yuan ◽  
Wu Jiao ◽  
Yanfeng Liu ◽  
Wenxue Ye ◽  
Xiue Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Dna Methylation ◽  
Hexaploid Wheat ◽  
Genetic Model ◽  
Tetraploid Wheat ◽  
Epigenetic Changes ◽  
Wheat Evolution ◽  
D Genome ◽  
Polyploid Evolution ◽  
Genome Separation

Abstract Background Wheat is a powerful genetic model for studying polyploid evolution and crop domestication. Hexaploid bread wheat was formed by two rounds of interspecific hybridization and polyploidization, processes which are often accompanied by genetic and epigenetic changes, including DNA methylation. However, the extent and effect of such changes during wheat evolution, particularly from tetraploid-to-hexaploid wheat, are currently elusive. Results Here we report genome-wide DNA methylation landscapes in extracted tetraploid wheat (ETW, AABB), natural hexaploid wheat (NHW, AABBDD), resynthesized hexaploid wheat (RHW, AABBDD), natural tetraploid wheat (NTW, AABB), and diploid (DD). In the endosperm, levels of DNA methylation, especially in CHG (H=A, T, or C) context, were dramatically decreased in the ETW relative to natural hexaploid wheat; hypo-differentially methylated regions (DMRs) (850,832) were 24-fold more than hyper-DMRs (35,111). Interestingly, those demethylated regions in ETW were remethylated in the resynthesized hexaploid wheat after the addition of the D genome. In ETW, hypo-DMRs correlated with gene expression, and TEs were demethylated and activated, which could be silenced in the hexaploid wheat. In NHW, groups of TEs were dispersed in genic regions of three subgenomes, which may regulate the expression of TE-associated genes. Further, hypo-DMRs in ETW were associated with reduced H3K9me2 levels and increased expression of histone variant genes, suggesting concerted epigenetic changes after separation from the hexaploid. Conclusion Genome merger and separation provoke dynamic and reversible changes in chromatin and DNA methylation. These changes correlate with altered gene expression and TE activity, which may provide insights into polyploid genome and wheat evolution.

Introduction of the D-genome chromosomes from bread wheat into hexaploid triticale with a complete rye genome

Genome ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 425-430 ◽  
Author(s):  
A. J. Lukaszewski ◽  
B. Apolinarska ◽  
J. P. Gustafson
Keyword(s):  
Key Words ◽  
Bread Wheat ◽  
Hexaploid Triticale ◽  
Genome Chromosome ◽  
D Genome ◽  
Homozygous Condition ◽  
C Banding ◽  
B Genome ◽  
Chromosome Substitutions ◽  
Triticosecale Wittmack

Hexaploid triticale (× Triticosecale Wittmack) lines selected from the progeny of octoploid × tetraploid triticale hybrids were karyotyped using C-banding. The number of D-genome chromosome pairs substituted for A- and (or) B-genome chromosomes ranged from 0 to 4, averaging 2.1 substitutions per line. Every D-genome chromosome was present in at least 1 of the 70 lines analyzed. The most frequent were chromosomes 3D and 6D, followed by 1D. Of the 14 possible substitutions, 12 were present in the homozygous condition, 1 (4D/4B) was still segregating, and 6D/6B was absent. With the exception of one 1D/1R substitution and one 7RS/4DS translocation, all lines had a complete rye genome. Key words: triticale, chromosome substitutions, D genome.

Over-expression of HMW glutenin subunit Glu-B1 7x in hexaploid wheat varieties (Triticum aestivum)

2004 ◽  
Vol 55 (5) ◽  
pp. 577 ◽  
Author(s):  
M-J. Vawser ◽  
G. B. Cornish
Keyword(s):  
Bread Wheat ◽  
Expression Profiles ◽  
Major Effect ◽  
Dough Strength ◽  
D Genome ◽  
Wheat Varieties ◽  
B Genome ◽  
Rp Hplc ◽  
Hmw Glutenin ◽  
Different Origin

In Canada in 1993, a special market class of wheat, Canada Western Extra Strong (CWES), was established to segregate wheat varieties known to produce very strong and extensible doughs. These exceptional dough properties enable CWES cultivars to be blended with wheats of lesser quality as well as being suited to the manufacture of frozen dough products. The high molecular weight (HMW) glutenin allele (Glu-B1al) that confers these properties, particularly dough strength, has now been identified. Typically, the presence of the Glu-B1al (7+8*) allele is associated with the overexpression of HMW-GS 1Bx 7. RP-HPLC was used to quantify the proportion (% area) of individual HMW-GS relative to total HMW-GS in wheat varieties of different origin. The B genome contributed the highest percentage of HMW-GS, with the exception of Glu-B1d (6+8*) where the D genome contributed the most. Cultivars that possessed the Glu-B1al allele contained a significantly higher (P < 0.001) proportion of HMW-GS (56.80 ± 3.25%) encoded by the B genome. This suggests that the proportion of Glu-B1 subunits, relative to the total amount of HMW-GS expressed, has a major effect on dough strength. We also identified germplasm, of different origin, that contains the Glu-B1al allele and overexpresses subunit 7, including the most likely source of this allele in bread wheat cultivars. The Glu-B1al allele in the varieties identified in this paper could be traced, at least through one parent, to the Argentinean bread wheat cultivar Klein Universal II. RP-HPLC elution and expression profiles of various common HMW-GS are also discussed.

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.

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