The phylogeny of the polyploid wheats Triticum aestivum (bread wheat) and Triticum turgidum (macaroni wheat)

Genome ◽  
1987 ◽  
Vol 29 (5) ◽  
pp. 722-737 ◽  
Author(s):  
K. Kerby ◽  
J. Kuspira
Keyword(s):  
Triticum Aestivum ◽  
Triticum Turgidum ◽  
Diploid Species ◽  
Triticum Monococcum ◽  
Aegilops Speltoides ◽  
Triticum Urartu ◽  
B Genome ◽  
Aegilops Longissima ◽  
A Genome ◽  
Genome Donors

The phylogeny of the polyploid wheats has been the subject of intense research and speculation during the past 70 years. Various experimental approaches have been employed to ascertain the diploid progenitors of these wheats. The species having donated the D genome to Triticum aestivum has been unequivocally identified as Aegilops squarrosa. On the basis of evidence from many studies, Triticum monococcum has been implicated as the source of the A genome in both Triticum turgidum and Triticum aestivum. However, numerous studies since 1968 have shown that Triticum urartu is very closely related to Triticum monococcum and that it also carries the A genome. These studies have prompted the speculation that Triticum urartu may be the donor of this chromosome set to the polyploid wheats. The donor of the B genome to Triticum turgidum and Triticum aestivum remains equivocal and controversial. Six different diploid species have been implicated as putative B genome donors: Aegilops bicornis, Aegilops longissima, Aegilops searsii, Aegilops sharonensis, Aegilops speltoides, and Triticum urartu. Until recently, evidence presented by different researchers had not permitted an unequivocal identification of the progenitor of the B genome in polyploid wheats. Recent studies, involving all diploid and polyploid wheats and putative B genome donors, lead to the conclusion that Aegilops speltoides and Triticum urartu can be excluded as B genome donors and that Aegilops searsii is the most likely source of this chromosome set. The possibility of the B genome having arisen from an AAAA autotetraploid or having a polyphyletic origin is discussed. Key words: phylogeny; Triticum aestivum; Triticum turgidum; A, B, and D genomes.

Biochemical data bearing on the origin of the B genome in the polyploid wheats

Genome ◽  
1990 ◽  
Vol 33 (3) ◽  
pp. 360-368 ◽  
Author(s):  
K. Kerby ◽  
J. Kuspira ◽  
B. L. Jones ◽  
G. L. Lookhart
Keyword(s):  
Amino Acid ◽  
B Chromosome ◽  
Amino Acid Sequences ◽  
Chromosome 1 ◽  
Aegilops Speltoides ◽  
B Genome ◽  
Aegilops Longissima ◽  
Aegilops Sharonensis ◽  
A Genome ◽  
Genome Donors

For many years each of the species Aegilops bicornis, Aegilops longissima, Aegilops searsii, Aegilops sharonensis, Aegilops speltoides, and Triticum urartu has been implicated as the donor of the B genome in the polyploid wheats. Biochemical and cytological data have revealed that T. urartu possesses a genome similar to that of T. monococcum, and therefore it may be the source of the A genome in T. turgidum and T. aestivum. This revelation therefore excludes T. urartu from the list of putative B-genome donors. To determine which of the remaining species is the source of the B chromosome set, the amino acid sequences of their purothionins were compared with that of the α1 purothionin coded for by the Pur-1B gene on chromosome 1 in the B genome of T. turgidum and T. aestivum. The residue sequences of this protein from Ae. bicornis, Ae. longissima, Ae. searsii, Ae. sharonensis, and Ae. speltoides differed by 1, 6, 1, 1, and 2 amino acid substitutions, respectively, from the α1 protein. These results suggest that either Ae. bicornis, Ae. searsii, or Ae. sharonensis was the most likely donor of the B genome. If the B genome in the polyploid wheats is monophyletic in origin, the collective findings of this and other investigations indicate that Ae. searsii is the most likely donor. The possibility that the B genome in the polyploid wheats could have a polyphyletic origin is also discussed.Key words: polyploid wheats, putative B-genome donors, purothionins, monophyletic, polyphyletic.

Biochemical data bearing on the relationship between the genome of Triticum urartu and the A and B genomes of the polyploid wheats

Genome ◽  
1988 ◽  
Vol 30 (4) ◽  
pp. 576-581 ◽  
Author(s):  
K. Kerby ◽  
J. Kuspira ◽  
B. L. Jones
Keyword(s):  
Amino Acid ◽  
Triticum Turgidum ◽  
Amino Acid Sequences ◽  
Triticum Monococcum ◽  
Triticum Urartu ◽  
B Genome ◽  
Genome Donor ◽  
A Genome ◽  
The Relationship ◽  
Donor Species

To determine whether the Triticum urartu genome is more closely related to the A or B genome of the polyploid wheats, the amino acid sequence of its purothionin was compared to the amino acid sequences of the purothionins in Triticum monococcum, Triticum turgidum, and Triticum aestivum. The residue sequence of the purothionin from T. urartu differs by five and six amino acid substitutions respectively from the α1 and α2 forms coded for by genes in the B and D genomes, and is identical to the β form specified by a gene in the A genome. Therefore, the T. urartu purothionin is either coded by a gene in the A genome or a chromosome set highly homologous to it. The results demonstrate that at least a portion of the T. urartu and T. monococcum genomes is homologous and probably identical. A variety of other studies have also shown that T. urartu is very closely related to T. monococcum and, in all likelihood, also possesses the A genome. Therefore, it could be argued that either T. urartu and T. monococcum are the same species or that T. urartu rather than T. monococcum is the source of the A genome in T. turgidum and T. aestivum. Except for Johnson's results, our data and that of others suggest a revised origin of polyploid wheats. Specifically, the list of six putative B genome donor species is reduced to five, all members of the Sitopsis section of the genus Aegilops.Key words: Triticum monococcum, Triticum urartu, polyploid wheats, genomes A and B, purothionins.

Transferability of wheat microsatellites to diploid Aegilops species and determination of chromosomal localizations of microsatellites in the S genome

Genome ◽  
2005 ◽  
Vol 48 (6) ◽  
pp. 959-970 ◽  
Author(s):  
I G Adonina ◽  
E A Salina ◽  
E G Pestsova ◽  
M S Röder
Keyword(s):  
Triticum Aestivum ◽  
Microsatellite Markers ◽  
Ssr Markers ◽  
Phylogenetic Relationships ◽  
Diploid Species ◽  
Aegilops Speltoides ◽  
Addition Lines ◽  
Chromosome Addition ◽  
Aegilops Longissima ◽  
Chromosome Addition Lines

Overall, 253 genomic wheat (Triticum aestivum) microsatellite markers were studied for their transferability to the diploid species Aegilops speltoides, Aegilops longissima, and Aegilops searsii, representing the S genome. In total, 88% of all the analyzed primer pairs of markers derived from the B genome of hexaploid wheat amplified DNA fragments in the genomes of the studied species. The transferability of simple sequence repeat (SSR) markers of the T. aestivum A and D genomes totaled 74%. Triticum aestivum – Ae. speltoides, T. aestivum – Ae. longissima, and T. aestivum – Ae. searsii chromosome addition lines allowed us to determine the chromosomal localizations of 103 microsatellite markers in the Aegilops genomes. The majority of them were localized to homoeologous chromosomes in the genome of Aegilops. Several instances of nonhomoeologous localization of T. aestivum SSR markers in the Aegilops genome were considered to be either amplification of other loci or putative translocations. The results of microsatellite analysis were used to study phylogenetic relationships among the 3 species of the Sitopsis section (Ae. speltoides, Ae. longissima, and Ae. searsii) and T. aestivum. The dendrogram obtained generally reflects the current views on phylogenetic relationships among these species.Key words: Triticum aestivum, Aegilops speltoides, Aegilops longissima, Aegilops searsii, microsatellite, SSR, chromosome addition lines, phylogeny.

scholarly journals Equivalence of the A genome of bread wheat and that of Triticum urartu

1976 ◽  
Vol 27 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Victor Chapman ◽  
T. E. Miller ◽  
Ralph Riley
Keyword(s):  
Triticum Aestivum ◽  
Hexaploid Wheat ◽  
Homoeologous Pairing ◽  
Triticum Urartu ◽  
B Genome ◽  
Chromosome 5B ◽  
A Genome ◽  
Telocentric Chromosomes ◽  
Mother Cells ◽  
Pairing Behaviour

SUMMARYLines of Triticum aestivum Chinese Spring (2n = 6x = 42) which were ditelocentric or doubly ditelocentric, in turn, for the 14 chromosomes of the A and B genomes were pollinated by Triticum urartu (2n = 14). The behaviour of the marked telocentric chromosomes was scored in the 14 distinct hybrids obtained from these pollinations. In 6 of the hybrids in which different A genome chromosomes were marked by telocentrics there were from 50 to 80% of the pollen mother cells in which the telocentrics were paired. In the seven hybrids in which different B genome chromosomes were marked the telocentrics were never paired. It was concluded that the genome of T. urartu matched very closely the A genome of hexaploid wheat and that it did not correspond, as had been proposed by Johnson, to the B genome. The pairing behaviour of the 14 T. aestivum × T. urartu hybrids was compared with earlier results obtained from hybrids between T. aestivum and T. boeoticum. It was proposed that the higher trivalent frequencies seen in the T. boeoticum hybrids could be due to homoeologous pairing and that the genotype of T. boeoticum has the capacity partly to suppress the activity of the Ph locus of chromosome 5B of wheat, as a result of which homoeologous pairing is normally prevented.

Genetic and cytogenetic analyses of the A genome of Triticum monococcum. II. The mode of inheritance of spring versus winter growth habit

1986 ◽  
Vol 28 (1) ◽  
pp. 88-95 ◽  
Author(s):  
J. Kuspira ◽  
J. Maclagan ◽  
K. Kerby ◽  
R. N. Bhambhani
Keyword(s):  
Triticum Aestivum ◽  
Growth Habit ◽  
Major Gene ◽  
Diploid Species ◽  
Triticum Monococcum ◽  
Allelic Series ◽  
A Genome ◽  
Multiple Allelic Series ◽  
Winter Growth Habit ◽  
Mode Of Inheritance

The study on the mode of inheritance of spring versus winter growth habit in Triticum monococcum is the first in a diploid wheat species. The results are discussed in light of the information available on the genetics and cytogenetics of this character in Triticum aestivum. Two spring habit and six winter habit lines were used in these investigations. Statistical analyses of progenies in each of these lines clearly established the true-breeding nature of all eight lines with respect to days to heading. Analysis of F1 and F2 results of crosses between the two spring habit lines 68 and 293 showed the following: (i) neither line carries winter habit alleles at any of the major gene loci determining growth habit; and (ii) four of five minor allele pairs determine the phenotypic differences between them. Monohybrid F2 and testcross ratios in crosses between spring habit line 68 and each of the six winter lines lead to the following conclusions: (i) differences between spring and winter growth habit in each cross are due to alleles of one major gene; (ii) the allele for spring habit is completely dominant to that for winter habit in each cross; and (iii) all these lines are genotypically identical or very similar at all modifying gene loci. These results imply that only one major gene determines growth habit in this species. Diallel (critical) crosses among the six recessive lines indicate that complementation does not occur in any of the F1's. Therefore, all these recessive genes represent mutations in the same gene. If these results are characteristic of all winter lines in Triticum monococcum, they permit the initial conclusion that only one major gene determines growth habit in this diploid species. This locus is in all likelihood the VrnI locus since it is the only one of the five major genes identified for growth habit, that is present in the A genome of Triticum aestivum. All six recessive lines respond to natural vernalization. This lends further support to our initial conclusion. Because the six recessive lines head at five different times we conclude that a multiple allelic series occurs at this locus. Specifically, at least three and probably five recessive alleles responsible for different heading dates among the winter lines, and at least one dominant allele for spring habit, occur at this locus.Key words: Triticum, complementation, quantitative, vernalization, alleles, multiple.

THE RELATIONSHIP BETWEEN THE GENOME OF TRITICUM URARTU AND THE A AND B GENOMES OF TRITICUM AESTIVUM

1976 ◽  
Vol 18 (2) ◽  
pp. 371-377 ◽  
Author(s):  
Jan Dvořák
Keyword(s):  
Triticum Aestivum ◽  
Chromosome Pairing ◽  
Chinese Spring ◽  
Triticum Urartu ◽  
B Genome ◽  
A Genome ◽  
The Relationship

Triticum urartu (2n = 14) was crossed with T. aestivum lines ditelosomic for chromosomes of the A and B genomes. Except for telosome 4Aα, the rest of the telosomes of the A genome paired in these hybrids while telosomes of the B genome did not pair. This indicates that T. urartu cannot be the donor of the B genome of 4x and 6x wheat, but carries an A genome. Compared to the rest of the hybrids, pairing of T. urartu chromosomes was significantly reduced in hybrids deficient for chromosome arms 5AS or 5BS. It is suggested that this reduction in chromosome pairing resulted from the absence of genes which promote homoelogous pairing and which are normally present on chromosome arms 5AS and 5BS in Chinese Spring.

scholarly journals Quantification of genetic relationships among A genomes of wheats

Genome ◽  
2006 ◽  
Vol 49 (4) ◽  
pp. 297-305 ◽  
Author(s):  
A Brandolini ◽  
P Vaccino ◽  
G Boggini ◽  
H Özkan ◽  
B Kilian ◽  
...  
Keyword(s):  
Phylogenetic Tree ◽  
Triticum Turgidum ◽  
Genetic Relationships ◽  
Triticum Monococcum ◽  
Aflp Fingerprinting ◽  
Triticum Urartu ◽  
D Genome ◽  
Genome Donor ◽  
A Genome

The genetic relationships of A genomes of Triticum urartu (Au) and Triticum monococcum (Am) in polyploid wheats are explored and quantified by AFLP fingerprinting. Forty-one accessions of A-genome diploid wheats, 3 of AG-genome wheats, 19 of AB-genome wheats, 15 of ABD-genome wheats, and 1 of the D-genome donor Ae. tauschii have been analysed. Based on 7 AFLP primer combinations, 423 bands were identified as potentially A genome specific. The bands were reduced to 239 by eliminating those present in autoradiograms of Ae. tauschii, bands interpreted as common to all wheat genomes. Neighbour-joining analysis separates T. urartu from T. monococcum. Triticum urartu has the closest relationship to polyploid wheats. Triticum turgidum subsp. dicoccum and T. turgidum subsp. durum lines are included in tightly linked clusters. The hexaploid spelts occupy positions in the phylogenetic tree intermediate between bread wheats and T. turgidum. The AG-genome accessions cluster in a position quite distant from both diploid and other polyploid wheats. The estimates of similarity between A genomes of diploid and polyploid wheats indicate that, compared with Am, Au has around 20% higher similarity to the genomes of polyploid wheats. Triticum timo pheevii AG genome is molecularly equidistant from those of Au and Am wheats.Key words: A genome, Triticum, genetic relationships, AFLP.

Powdery mildew resistance in some new wheat amphiploids (2n = 6x = 42) derived from A- and S-genome diploid progenitors

2012 ◽  
Vol 10 (3) ◽  
pp. 165-170 ◽  
Author(s):  
Khola Rafique ◽  
Awais Rasheed ◽  
Alvina Gul Kazi ◽  
Hadi Bux ◽  
Farah Naz ◽  
...  
Keyword(s):  
Powdery Mildew ◽  
Durum Wheat ◽  
Bread Wheat ◽  
Triticum Turgidum ◽  
Seedling Stage ◽  
Aegilops Speltoides ◽  
Germplasm Screening ◽  
B Genome ◽  
A Genome ◽  
Major Resistance Genes

Triticum urartu possesses the Au genome common to bread wheat. Similarly, Triticum monococcum contains the Am genome, which is closely related to the A-genome donor of bread wheat. Aegilops speltoides of the Sitopsis section has the S genome, which is most similar to the B genome of bread and durum wheat when compared with all other wild grasses. Amphiploids developed through bridge crossing between Am/Au and S-genome diploid resources and elite durum cultivars demonstrate enormous diversity to improve both bread and durum wheat cultivars. We evaluated such A-genome amphiploids (Triticum turgidum × T. urartu and T. turgidum × T. monococcum, 2n = 6x = 42; BBAAAmAm/AuAu) and S-genome amphiploids (T. turgidum × Ae. speltoides, 2n = 6x = 42; AABBSS) along with their durum parents (AABB) for their resistance to powdery mildew (PM) at the seedling stage. The results indicated that 104 accessions (53.6%) of A-genome amphiploids (AABBAmAm/AuAu) were resistant to PM at the seedling stage. Of their 24 durum parents, five (20.83%) were resistant to PM and 16 (66.6%) were moderately tolerant. Similarly, ten (50%) accessions of S-genome amphiploids (BBAASS) possessed seedling PM resistance, suggesting a valuable source of major resistance genes. PM screening of the amphiploids and parental durum lines showed that resistance was contributed either by the diploid progenitors or durum parents, or both. We also observed the suppression of resistance in several cases; for example, resistance in durum wheat was suppressed in respective amphiploids. The results from this germplasm screening will facilitate their utilization to genetically control PM and widen the genetic base of wheat.

Cytological evidence bearing on the origin of the B genome in polyploid wheats

Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 36-43 ◽  
Author(s):  
K. Kerby ◽  
J. Kuspira
Keyword(s):  
Dna Hybridization ◽  
Triticum Turgidum ◽  
Root Tip ◽  
Cytological Evidence ◽  
B Genome ◽  
Genome Donor ◽  
The One ◽  
Genome Donors ◽  
Tip Cells ◽  
Root Tip Cells

To help elucidate the origin of the B genome in polyploid wheats, karyotypes of Triticum turgidum, Triticum monoccum, and all six purported B genome donors were compared. The analysis utilized a common cytological procedure that employed the most advanced equipment for the measurement of chromosome lengths at metaphase in root tip cells. A comparison of the karyotypes of T. turgidum and T. monococcum permitted the identification of B genome chromosomes of T. turgidum. These consist of two SAT pairs, one ST pair, three SM pairs, and one M pair of homologues. Comparisons of the chromosomes of the B genome of T. turgidum with the karyotypes of the six putative B genome donors showed that only the karyotype of Aegilops searsii was similar to the one deduced for the donor of the B genome in T. turgidum, suggesting that Ae. searsii is, therefore, the most likely donor of the B genome to the polyploid wheats. Support for this conclusion has been derived from geographic, DNA-hybridization, karyotype, morphological, and protein data reported since 1977. Reasons why the B genome donor has not been unequivocally identified are discussed.Key words: phylogeny, karyotypes, Triticum turgidum, Triticum monococcum, B genome, B genome donors.

A Centromeric Tandem Repeat Family Originating From a Part of Ty3/gypsy-Retroelement in Wheat and Its Relatives

Genetics ◽  
2003 ◽  
Vol 164 (2) ◽  
pp. 665-672 ◽  
Author(s):  
Zhi-Jun Cheng ◽  
Minoru Murata
Keyword(s):  
In Situ Hybridization ◽  
Tandem Repeats ◽  
Diploid Species ◽  
Upstream Region ◽  
Aegilops Speltoides ◽  
Repeat Family ◽  
B Genome ◽  
Intervening Sequences ◽  
Wild Diploid Species

AbstractFrom a wild diploid species that is a relative of wheat, Aegilops speltoides, a 301-bp repeat containing 16 copies of a CAA microsatellite was isolated. Southern blot and fluorescence in situ hybridization revealed that ∼250 bp of the sequence is tandemly arrayed at the centromere regions of A- and B-genome chromosomes of common wheat and rye chromosomes. Although the DNA sequence of this 250-bp repeat showed no notable homology in the databases, the flanking or intervening sequences between the repeats showed high homologies (>82%) to two separate sequences of the gag gene and its upstream region in cereba, a Ty3/gypsy-like retroelement of Hordeum vulgare. Since the amino acid sequence deduced from the 250 bp with seven CAAs showed some similarity (∼53%) to that of the gag gene, we concluded that the 250-bp repeats had also originated from the cereba-like retroelements in diploid wheat such as Ae. speltoides and had formed tandem arrays, whereas the 300-bp repeats were dispersed as a part of cereba-like retroelements. This suggests that some tandem repeats localized at the centromeric regions of cereals and other plant species originated from parts of retrotransposons.

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