Phylogenetic relationships of Triticum tauschii, the D-genome donor to hexaploid wheat. 4. Variation and chromosomal location of 5S DNA

Genome ◽  
1989 ◽  
Vol 32 (6) ◽  
pp. 1017-1025 ◽  
Author(s):  
E. S. Lagudah ◽  
B. C. Clarke ◽  
R. Appels
Keyword(s):  
Dna Sequences ◽  
Hexaploid Wheat ◽  
Chromosomal Location ◽  
Thermal Dissociation ◽  
D Genome ◽  
Triticum Tauschii ◽  
Main Cluster ◽  
Chinese Spring Wheat ◽  
Close Phylogenetic Relationship ◽  
5S Dna

The 5S DNA sequences in Triticum tauschii are organised in large clusters containing units that are primarily either 420 ("short") or 490 base pairs (bp) in length ("long"). The main cluster of short units was shown to be located on chromosome 1D in hexaploid wheat and is designated 5SDna-Dl, while the cluster of long units was shown to be on chromosome 5D and is designated 5SDna-D2. The chromosomal locations in hexaploid wheat most likely correspond to those in T. tauschii and this could be shown directly for the 5SDna-D2 locus by using a T. tauschii 5D substitution in 'Chinese Spring' wheat. The sequence alignment of units derived from 5SDna-D1 and 5SDna-D2 revealed three apparent deletions in the noncoding spacer region, which were fixed in units from 5SDna-D1, and one deletion, which was fixed in units from 5SDna-D2. A minor size class, 400 bp long and closely related to the units from 5SDna-D1, was found in 2 of 415 accessions surveyed. A continuous range of quantitative changes in the number of 5S DNA units at the two loci was evident with up to a 10-fold relative abundance level of units being found in some accessions. Triticum tauschii var. typica was particularly noteworthy in that many accessions showed more units at 5SDna-D2 relative to 5SDna-D1. Partial thermal dissociation experiments with radioactive probes, synthesized from either the short or long 5S DNA units, hybridized to genomic DNA showed that the population of units at the respective loci were relatively homogeneous and clearly distinct from each other. In addition, these experiments further established the close phylogenetic relationship between T. tauschii and the D genome of wheat.Key words: Triticum tauschii, 5S DNA, sequence variation, chromosomal location.

More than one origin of hexaploid wheat is indicated by sequence comparison of low-copy DNA

Genome ◽  
1998 ◽  
Vol 41 (3) ◽  
pp. 402-407 ◽  
Author(s):  
L E Talbert ◽  
L Y Smith ◽  
N K Blake
Keyword(s):  
Dna Sequences ◽  
Hexaploid Wheat ◽  
Restriction Site ◽  
Cereal Crop ◽  
Crop Species ◽  
Wheat Evolution ◽  
D Genome ◽  
Restriction Site Variation ◽  
Site Variation ◽  
Copy Dna

Allohexaploid bread wheat is grown on more acreage than any other cereal crop, yet variation at the DNA level seems to be less than that observed in many diploid crop species. A common explanation for the small amount of DNA-level variation is that a severe bottleneck event resulted from the polyploidization events that gave rise to hexaploid wheat, whereby wheat was genetically separated from its progenitors. In this report, we test the extent of the bottleneck separating wheat from its D-genome progenitor, Triticum tauschii, by comparative DNA sequence analysis. Restriction site variation of low-copy DNA sequences amplified by PCR showed an average of 2.9 and 2.4 alleles per primer set in T. tauschii and wheat, respectively. Two different restriction patterns were present in T. tauschii for DNA amplified with a primer set for the A1 locus. Both alleles were also present in wheat. Alleles at the A1 locus were cloned and 527 bp of sequence obtained from 12 and 13 diverse accessions of wheat and T. tauschii, respectively. Average genetic distance among the wheat alleles was similar to that among the T. tauschii alleles (0.0127 and 0.0133, respectively). Nucleotide differences indicated that two distinct alleles existed in T. tauschii, both of which were present in wheat. These data suggest that hexaploid wheat formed at least twice, and that the bottleneck separating wheat from T. tauschii may be less constrictive than previously supposed.Key words: wheat, evolution, DNA.

Assignment of the genomic affinities of chromosomes from polyploid Elymus species added to wheat

Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 70-82 ◽  
Author(s):  
Bikram S. Gill ◽  
Kay L. D. Morris ◽  
Rudi Appels
Keyword(s):  
Repetitive Dna ◽  
Dna Sequences ◽  
Single Gene ◽  
Dna Probes ◽  
Addition Lines ◽  
Cross Hybridization ◽  
Elymus Trachycaulus ◽  
Chinese Spring Wheat ◽  
5S Dna ◽  
Elymus Species

Genomic DNAs from 10 disomic addition, substitution, or translocation chromosomes from tetraploid Elymus trachycaulus (SSHH) and 13 tetraploid Elymus ciliaris (SSYY) in Chinese Spring wheat were assayed with 18S–28S rDNA (Nor), 5S DNA, Adh, α-amylase, β-glucanase gene clones, and S-genome and H-genome repetitive DNA sequences. The rDNA from the S genome and 5S DNA from the S and H genomes, under high stringency Southern blot analysis, distinguished S-genome and H-genome loci on individual Elymus chromosomes. The single gene, or low copy gene probes (Adh and others), allowed identification of different addition lines and provided information on the gene synteny relationships of Elymus chromosomes with wheat chromosomes. The S-genome specific and H-genome repetitive DNA probes were not useful in assigning genomic affinities, due to some cross-hybridization between these genomes using these probes and (or) the occurrence of large numbers of translocations in polyploid genomes of Elymus species. However, the repetitive DNA probes provided diagnostic phenotypic markers for identification of individual Elymus addition lines. Moreover, since S- and H-genome DNA sequences were virtually absent from wheat, they were excellent markers for the detection of Elymus chromatin in wheat. The array of DNA probes should prove useful in chromosome manipulation in resistance transfer from Elymus into wheat.Key words: Triticeae, Elymus, aneuploid, DNA probe.

The Ha locus of wheat: Identification of a polymorphic region for tracing grain hardness in crosses

Genome ◽  
1999 ◽  
Vol 42 (6) ◽  
pp. 1242-1250 ◽  
Author(s):  
M Turner ◽  
Y Mukai ◽  
P Leroy ◽  
B Charef ◽  
R Appels ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Hexaploid Wheat ◽  
Aegilops Tauschii ◽  
Grain Hardness ◽  
High Sequence Identity ◽  
D Genome ◽  
Sequence Identity ◽  
Group 5 ◽  
Grain Softness ◽  
Puroindoline A

The grain softness proteins or friabilins are known to be composed of three main components: puroindoline a, puroindoline b, and GSP-1. cDNAs for GSP-1 have previously been mapped to group-5 chromosomes and their location on chromosome 5D is closely linked to the grain hardness (Ha) locus of hexaploid wheat. A genomic DNA clone containing the GSP-1 gene (wGSP1-A1) from hexaploid wheat has been identified by fluorescent in situ hybridization as having originated from the distal end of the short arm of chromosome 5A. A genomic clone containing the gene (wGSP1-D1) was also isolated from Aegilops tauschii, the donor of the D genome to bread wheat. There are no introns in the GSP-1 genes, and there is high sequence identity between wGSP1-A1 and wGSP1-D1 up to 1 kb 5' and 300 bp 3' to wGSP1-D1. However, regions further upstream and downstream of wGSP1-D1 share no significant sequence identity to corresponding sequences in wGSP1-A1. These regions therefore identified potentially valuable sequences for tracing the Ha locus through assaying polymorphic DNA sequences. The sequence from 300 to 500 bp 3' to wGSP1-D1 (wGSP1-D13) was mapped to the Ha locus in a mapping population. wGSP1-D13 was also tightly linked to genes for puroindoline a and puroindoline b which have been previously mapped to be at the Ha locus. In addition wGSP1-D13 was used to detect RFLPs between near isogenic soft and hard Falcon lines and in a random selection of soft and hard wheats.Key words: wheat, grain hardness, chromosome 5, puroindoline, GSP-1.

Chromosomal Location of Hessian Fly–Resistance Genes H22, H23, and H24 Derived from Triticum tauschii in the D Genome of Wheat

1993 ◽  
Vol 84 (2) ◽  
pp. 142-145 ◽  
Author(s):  
W. J. Raupp ◽  
A. Amri ◽  
J. H. Hatchett ◽  
B. S. Gill ◽  
D. L. Wilson ◽  
...  
Keyword(s):  
Resistance Genes ◽  
Chromosomal Location ◽  
Hessian Fly ◽  
D Genome ◽  
Triticum Tauschii ◽  
Hessian Fly Resistance

Chromosomal location of genes for supernumerary spikelet in tetraploid wheat

Genome ◽  
1990 ◽  
Vol 33 (4) ◽  
pp. 515-520 ◽  
Author(s):  
D. L. Klindworth ◽  
N. D. Williams ◽  
L. R. Joppa
Keyword(s):  
Chromosomal Location ◽  
Triticum Turgidum ◽  
Tetraploid Wheat ◽  
Substitution Lines ◽  
D Genome ◽  
Strong Inhibitor ◽  
Branched Spike ◽  
Chinese Spring Wheat ◽  
Monosomic Addition ◽  
A Minor

The supernumerary spikelet (SS) trait of durum wheat (Triticum turgidum L.), including the ramified and four-rowed spike traits, is characterized by an increased number of spikelets per spike. Chromosomal location of the SS gene(s) was determined by crossing the ramified spike line PI349056 to the set of 'Langdon' D-genome disomic substitution lines. Double monosomic F1 plants were backcrossed to PI349056 and the testcross F1 plants were classified for chromosome pairing and spike type. Segregation for spike type was observed in the testcross F2. Data indicated that the major SS gene was located on chromosome 2A. Subsequent crosses with the 'Langdon' 2A telosomics indicated that the major SS gene was located on the short arm of chromosome 2A. Segregation of the testcross F2 indicated that a minor SS gene was located on chromosome 2B. Results also indicated that inhibitors of SS may be located on the D-genome chromosomes and an additional experiment was designed to test this hypothesis. Eight D-genome monosomic addition lines were developed by backcrossing PI349056 from one to three times to plants containing D-genome univalents. The test populations contained two cytological types of plants, disomics having 14 pairs of durum chromosomes and D-genome monosomic additions having 14 pairs of durum chromosomes plus a D-genome monosome. Comparison of these two types of plants indicated that chromosome 2D (from 'Chinese Spring' wheat) had a strong inhibitor of SS expression.Key words: Triticum, branched spike, ramified spike, four-rowed spike, cytogenetics.

Sign in / Sign up

Export Citation Format

Share Document