Development and discrimination of 12 double ditelosomics in tetraploid wheat cultivar DR147

As an important group in Triticum, tetraploid wheat plays a significant role in the research of wheat evolution. Several complete aneuploid sets of common wheat have provided valuable tools for genetic and breeding studies, while similar aneuploids of tetraploid wheat are still not well developed. Here, 12 double ditelosomics developed in Triticum turgidum L. var. durum cultivar DR147 (excluding dDT2B and dDT3A) were reported. Hybrids between DR147 and the original double-ditelosomic dDT2B of Langdon lost vigor and died prematurely after the three-leaf stage; therefore, the dDT2B line was not obtained. The cytogenetic behaviors and phenotypic characteristics of each line were detailedly described. To distinguish the entire chromosome complement of tetraploid wheat, the DR147 karyotype was established by fluorescence in situ hybridization (FISH), using the Aegilops tauschii clone pAsl and the barley clone pHvG38 as probes. FISH using a cereal-specific centromere repeat (6C6) probe suggested that all the lines possessed four telosomes, except for 4AS of double-ditelosomic dDT4A, which carried a small segment of the long arm. On the basis of the idiogram of DR147, these lines were successfully discriminated by FISH using the probes pAsl and pHvG38 and were then accurately designated.

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Identification of the entire chromosome complement of bread wheat by two-colour FISH

Genome ◽

10.1139/g97-077 ◽

1997 ◽

Vol 40 (5) ◽

pp. 589-593 ◽

Cited By ~ 125

Author(s):

C. Pedersen ◽

P. Langridge

Keyword(s):

In Situ Hybridization ◽

Fluorescence In Situ Hybridization ◽

Dna Sequences ◽

Banding Pattern ◽

Aegilops Tauschii ◽

Chromosome Complement ◽

Chromosome Identification ◽

Satellite Sequence ◽

Entire Chromosome

Using the Aegilops tauschii clone pAs1 together with the barley clone pHvG38 for two-colour fluorescence in situ hybridization (FISH) the entire chromosome complement of hexaploid wheat was identified. The combination of the two probes allowed easy discrimination of the three genomes of wheat. The banding pattern obtained with the pHvG38 probe containing the GAA-satellite sequence was identical to the N-banding pattern of wheat. A detailed idiogram was constructed, including 73 GAA bands and 48 pAs1 bands. Identification of the wheat chromosomes by FISH will be particularly useful in connection with the physical mapping of other DNA sequences to chromosomes, or for chromosome identification in general, as an alternative to C-banding.Key words: Triticum aestivum, chromosome identification, fluorescence in situ hybridization, repetitive DNA sequences.

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Langdon durum disomic substitution lines and aneuploid analysis in tetraploid wheat

Genome ◽

10.1139/g88-038 ◽

1988 ◽

Vol 30 (2) ◽

pp. 222-228 ◽

Cited By ~ 120

Author(s):

L. R. Joppa ◽

N. D. Williams

Keyword(s):

Chromosomal Location ◽

Triticum Turgidum ◽

Wheat Cultivar ◽

Tetraploid Wheat ◽

Phenotypic Characteristics ◽

Substitution Lines ◽

D Genome ◽

Chromosome Transmission ◽

Complete Set ◽

Aneuploid Analysis

A complete set of disomic substitution lines have been developed in the tetraploid wheat cultivar Langdon (Triticum turgidum L. var. durum). These aneuploid lines each have a pair of durum wheat homoeologues replaced by a pair of D-genome chromosomes transferred from 'Chinese Spring' hexaploid wheat. They can be used to determine the chromosomal location of genes, to transfer chromosomes from one cultivar or line of tetraploid wheat to another, to study the cytogenetics of tetraploid wheat, to determine gene linkages, and to identify chromosomes involved in translocations. Their phenotypic characteristics, their cytogenetic behavior, and suggested methods for their use are described.Key words: cytogenetics, monosomic, chromosome transmission, telosomic, chromosome substitution.

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Wheat, Rye, and Barley Genomes Can Associate during Meiosis in Newly Synthesized Trigeneric Hybrids

Plants ◽

10.3390/plants10010113 ◽

2021 ◽

Vol 10 (1) ◽

pp. 113

Author(s):

María-Dolores Rey ◽

Carmen Ramírez ◽

Azahara C. Martín

Keyword(s):

Chromosome Segregation ◽

Genome Duplication ◽

Triticum Turgidum ◽

Aegilops Tauschii ◽

Genomic In Situ Hybridization ◽

Hordeum Chilense ◽

Genomic Constitution ◽

Chromosome Associations ◽

High Level

Polyploidization, or whole genome duplication (WGD), has an important role in evolution and speciation. One of the biggest challenges faced by a new polyploid is meiosis, in particular, discriminating between multiple related chromosomes so that only homologs recombine to ensure regular chromosome segregation and fertility. Here, we report the production of two new hybrids formed by the genomes of species from three different genera: a hybrid between Aegilops tauschii (DD), Hordeum chilense (HchHch), and Secale cereale (RR) with the haploid genomic constitution HchDR (n = 7× = 21); and a hybrid between Triticum turgidum spp. durum (AABB), H. chilense, and S. cereale with the constitution ABHchR (n = 7× = 28). We used genomic in situ hybridization and immunolocalization of key meiotic proteins to establish the chromosome composition of the new hybrids and to study their meiotic behavior. Interestingly, there were multiple chromosome associations at metaphase I in both hybrids. A high level of crossover (CO) formation was observed in HchDR, which shows the possibility of meiotic recombination between the different genomes. We succeeded in the duplication of the ABHchR genome, and several amphiploids, AABBHchHchRR, were obtained and characterized. These results indicate that recombination between the genera of three economically important crops is possible.

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Development and characterization of Triticum turgidum – Aegilops comosa and T. turgidum – Ae. markgrafii amphidiploids

Genome ◽

10.1139/gen-2019-0215 ◽

2020 ◽

Vol 63 (5) ◽

pp. 263-273

Author(s):

Yuanyuan Zuo ◽

Qin Xiang ◽

Shoufen Dai ◽

Zhongping Song ◽

Tingyu Bao ◽

...

Keyword(s):

Genetic Improvement ◽

Triticum Turgidum ◽

Tetraploid Wheat ◽

Diploid Species ◽

Unreduced Gametes ◽

Stripe Rust Resistance ◽

Aegilops Comosa ◽

Direct Hybridization

Aegilops comosa and Ae. markgrafii are diploid progenitors of polyploidy species of Aegilops sharing M and C genomes, respectively. Transferring valuable genes/traits from Aegilops into wheat is an alternative strategy for wheat genetic improvement. The amphidiploids between diploid species of Aegilops and tetraploid wheat can act as bridges to overcome obstacles from direct hybridization and can be developed by the union of unreduced gametes. In this study, we developed seven Triticum turgidum – Ae. comosa and two T. turgidum – Ae. markgrafii amphidiploids. The unreduced gametes mechanisms, including first-division restitution (FDR) and single-division meiosis (SDM), were observed in triploid F1 hybrids of T. turgidum – Ae. comosa (STM) and T. turgidum – Ae. markgrafii (STC). Only FDR was observed in STC hybrids, whereas FDR or both FDR and SDM were detected in the STM hybrids. All seven pairs of M chromosomes of Ae. comosa and C chromosomes of Ae. markgrafii were distinguished by fluorescent in situ hybridization (FISH) probes pSc119.2 and pTa71 combinations with pTa-535 and (CTT)12/(ACT)7, respectively. Meanwhile, the chromosomes of tetraploid wheat and diploid Aegilops parents were distinguished by the same FISH probes. The amphidiploids possessed specific valuable traits such as multiple tillers, large seed size related traits, and stripe rust resistance that could be utilized in the genetic improvement of wheat.

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Molecular cytogenetic characterization of an alloplasmic durum wheat line with a portion of chromosome 1D of Triticum aestivum carrying the scsae gene

Genome ◽

10.1139/g03-090 ◽

2004 ◽

Vol 47 (1) ◽

pp. 206-214 ◽

Cited By ~ 13

Author(s):

Khwaja G Hossain ◽

Oscar Riera-Lizarazu ◽

Venugopal Kalavacharla ◽

M Isabel Vales ◽

Jamie L Rust ◽

...

Keyword(s):

Triticum Aestivum ◽

In Situ Hybridization ◽

Durum Wheat ◽

Triticum Turgidum ◽

Aegilops Tauschii ◽

Distal Region ◽

Specific Gene ◽

Homoeologous Recombination ◽

Male Sterile

Triticum aestivum (2n = 6x = 42, AABBDD) with Triticum longissimum (2n = 2x = 14; S1S1) cytoplasm ((lo) cytoplasm) has normal fertility and plant vigor. However, the nucleus of durum wheat (Triticum turgidum (2n = 4x = 28, AABB)) is incompatible with the T. longissimum cytoplasm, producing non-viable progeny. This incompatibility is alleviated by scsae, a species cytoplasm-specific (scs) gene, on the long arm of chromosome 1D (1DL) of common wheat. The hemizygous (lo) durum scsae line is male sterile and is maintained by crossing to normal durum wheat. After pollination, the seeds produced are either plump and viable (with scsae) or shriveled and inviable (without scsae). Thus, the chromosome with scsae is inherited as a whole without recombination. The objectives of this study were to characterize the chromosome carrying scsae and to determine the process through which this gene was introgressed into the (lo) durum background. Molecular marker analysis with 27 probes and primers mapped to homoeologous group 1 and genomic in situ hybridization using differentially labeled total genomic DNA of durum wheat and Aegilops tauschii suggest the presence of a 1AL segment in place of the distal region of 1DL. Owing to the absence of any detectable duplications or deletions, homoeologous recombination is the most likely mechanism by which this introgression occurred.Key words: homoeologous recombination, in situ hybridization, nuclear-cytoplasmic interaction, species cytoplasm specific gene

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Chromosomal and genome-wide molecular changes associated with initial stages of allohexaploidization in wheat can be transit and incidental

Genome ◽

10.1139/g11-028 ◽

2011 ◽

Vol 54 (8) ◽

pp. 692-699 ◽

Cited By ~ 16

Author(s):

Na Zhao ◽

Liying Xu ◽

Bo Zhu ◽

Mingjiu Li ◽

Huakun Zhang ◽

...

Keyword(s):

Genomic Instability ◽

Triticum Turgidum ◽

Aegilops Tauschii ◽

Tetraploid Wheat ◽

Great Majority ◽

Individual Plant ◽

Single Individual ◽

Genomic Changes ◽

General Response ◽

Allohexaploid Wheat

Genomic instability can be induced by nascent allopolyploidization in plants. However, most previous studies have not defined to what extent the allopolyploidy-induced rapid genomic instability represents a general response, and hence important to evolution, or merely incidental events occurring stochastically in a limited number of individuals. We report here that in a newly formed allohexaploid wheat line between tetraploid wheat Triticum turgidum subsp. durum (genome BBAA) and Aegilops tauschii (genome DD) a great majority of individual plants showed chromosomal stability and exhibited a genomic constitution similar to that of the present-day Triticum aestivum (genome BBAADD). In contrast, a single individual plant was identified at S2, which exhibited chromosomal instability in both number and structure based on multicolor genomic in situ hybridization (mc-GISH) analysis. Accordingly, this plant also manifested extensive changes at the molecular level including loss and gain of DNA segments and DNA methylation repatterning. Remarkably, the chromosomal and molecular instabilities that presumably occurred at S0 to S1 and (or) in the F1 hybrid were rapidly quenched by S2 and followed by stable transgenerational inheritance. Our results suggest that these stochastic and individual-specific rapid genomic changes, albeit interesting, probably have not played a major role in the speciation and evolution of common wheat, T. aestivum.

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

Genome ◽

10.1139/gen-2021-0074 ◽

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.

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Function and evolution of allelic variation of Sr13 conferring resistance to stem rust in tetraploid wheat ( Triticum turgidum L.)

The Plant Journal ◽

10.1111/tpj.15263 ◽

2021 ◽

Author(s):

Baljeet K. Gill ◽

Daryl L. Klindworth ◽

Matthew N. Rouse ◽

Jinglun Zhang ◽

Qijun Zhang ◽

...

Keyword(s):

Stem Rust ◽

Triticum Turgidum ◽

Allelic Variation ◽

Tetraploid Wheat

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The Independent Domestication of Timopheev’s Wheat: Insights from Haplotype Analysis of the Brittle rachis 1 (BTR1-A) Gene

Genes ◽

10.3390/genes12030338 ◽

2021 ◽

Vol 12 (3) ◽

pp. 338

Author(s):

Moran Nave ◽

Mihriban Taş ◽

John Raupp ◽

Vijay K. Tiwari ◽

Hakan Ozkan ◽

...

Keyword(s):

Promoter Region ◽

Haplotype Analysis ◽

Common Ancestor ◽

Triticum Turgidum ◽

Tetraploid Wheat ◽

Wheat Species ◽

Loss Of Function ◽

Brittle Rachis ◽

Gene Level ◽

Large Panel

Triticum turgidum and T. timopheevii are two tetraploid wheat species sharing T. urartu as a common ancestor, and domesticated accessions from both of these allopolyploids exhibit nonbrittle rachis (i.e., nonshattering spikes). We previously described the loss-of-function mutations in the Brittle Rachis 1 genes BTR1-A and BTR1-B in the A and B subgenomes, respectively, that are responsible for this most visible domestication trait in T. turgidum. Resequencing of a large panel of wild and domesticated T. turgidum accessions subsequently led to the identification of the two progenitor haplotypes of the btr1-A and btr1-B domesticated alleles. Here, we extended the haplotype analysis to other T. turgidum subspecies and to the BTR1 homologues in the related T. timopheevii species. Our results showed that all the domesticated wheat subspecies within T. turgidum share common BTR1-A and BTR1-B haplotypes, confirming their common origin. In T. timopheevii, however, we identified a novel loss-of-function btr1-A allele underlying a partially brittle spike phenotype. This novel recessive allele appeared fixed within the pool of domesticated Timopheev’s wheat but was also carried by one wild timopheevii accession exhibiting partial brittleness. The promoter region for BTR1-B could not be amplified in any T. timopheevii accessions with any T. turgidum primer combination, exemplifying the gene-level distance between the two species. Altogether, our results support the concept of independent domestication processes for the two polyploid, wheat-related species.

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

Genome ◽

10.1139/g06-114 ◽

2006 ◽

Vol 49 (12) ◽

pp. 1545-1554 ◽

Cited By ~ 17

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.

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