Implication of Triticum searsii as the B-genome donor to wheat using DNA hybridizations

1983 ◽  
Vol 21 (7-8) ◽  
pp. 745-760 ◽  
Author(s):  
J. Nath ◽  
James W. McNay ◽  
Charles M. Paroda ◽  
S. C. Gulati
Keyword(s):  
B Genome ◽  
Genome Donor ◽  
Dna Hybridizations

scholarly journals Isoenzymes and polyploidy I. Qualitative and quantitative isoenzyme studies in the Triticinae

1971 ◽  
Vol 18 (1) ◽  
pp. 57-69 ◽  
Author(s):  
R. Mitra ◽  
C. R. Bhatia
Keyword(s):  
Enzyme Activity ◽  
Parental Species ◽  
Gene Dosage ◽  
Species Variation ◽  
Polyploid Species ◽  
Qualitative And Quantitative ◽  
B Genome ◽  
Genome Donor ◽  
Variant Enzyme ◽  
Seed Extracts

SUMMARYIsoenzymes of alcohol (ADH), malate (MDH), glutamate (GDH) and isocitrate (IDH) dehydrogenases, and a fast migrating esterase (EST-l) were separated by disk electrophoresis from dry seed extracts of diploid, tetraploid, hexaploid and octaploid species or amphiploids belonging to the subtribe Triticinae. Only ADH and EST-l isoenzymes showed inter-species variation; the other dehydrogenases, which show stringent substrate specificities (‘critical’ enzymes), revealed the same pattern in all diploid and polyploid species. The qualitative zymogram studies showed that (1) the number of variant enzyme bands increased with the level of ploidy, (2) the amphiploid isoenzyme pattern was additive of the parental species, (3) enhancement in the number of bands was due to the presence of not only parental bands, but also hybrid bands formed by association between heteromonomers. Quantitative data were obtained by densitometry of the enzyme bands as well as spectrophotometric measurements of enzyme activity in crude extracts. Increase in the level of enzyme activity was observed with ploidy level. In spite of the evidence that all duplicate/triplicate genes are expressed, increased enzyme activity observed in the polyploid species was not proportional to the level of ploidy or expected gene dosage. On the basis of ADH and EST-l zymograms obtained in 2 × and 4 × wheat, probable zymograms for these enzymes in the B-genome donor to 4 × wheat were extrapolated. Neither Ae. speltoides nor Ae. bicornis showed the extrapolated ADH pattern. Amphiploids involving Ae. speltoides and Triticum monococcum or T. aegilopoides fully reproduced the EST-l zymogram of 4 × wheat, but not the ADH. Ae. bicornis × T. aegilopoides amphiploid showed an ADH zymogram similar to that of 4 × wheat, but the EST-l bands were different.

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.

scholarly journals Structure and expression analysis of genes encoding ADP-glucose pyrophosphorylase large subunit in wheat and its relatives

Genome ◽  
2016 ◽  
Vol 59 (7) ◽  
pp. 501-507 ◽  
Author(s):  
Xiao-Wei Zhang ◽  
Si-Yu Li ◽  
Ling-Ling Zhang ◽  
Qiang Yang ◽  
Qian-Tao Jiang ◽  
...  
Keyword(s):  
Large Subunit ◽  
Full Length ◽  
Starch Accumulation ◽  
Coding Region ◽  
D Genome ◽  
Reading Frame ◽  
B Genome ◽  
Genome Donor ◽  
Adp Glucose Pyrophosphorylase ◽  
Donor Species

ADP-glucose pyrophosphorylase (AGP), which consists of two large subunits (AGP-L) and two small subunits (AGP-S), controls the rate-limiting step in the starch biosynthetic pathway. In this study, a full-length open reading frame (ORF) of AGP-L gene (named as Agp2) in wheat and a series of Agp2 gene sequences in wheat relatives were isolated. The coding region of Agp2 contained 15 exons and 14 introns including a full-length ORF of 1566 nucleotides, and the deduced protein contained 522 amino acids (57.8 kDa). Generally, the phylogenetic tree of Agp2 indicated that sequences from A- and D-genome donor species were most similar to each other and sequences from B-genome donor species contained more variation. Starch accumulation and Agp2 expression in wheat grains reached their peak at 21 and 15 days post anthesis (DPA), respectively.

Transfer of a species cytoplasm specific (scs) gene from Triticum timopheevii to T. turgidum

Genome ◽  
1992 ◽  
Vol 35 (2) ◽  
pp. 238-243 ◽  
Author(s):  
S. S. Maan
Keyword(s):  
Common Wheat ◽  
Triticum Turgidum ◽  
Seed Viability ◽  
Male Parent ◽  
Alien Chromosome ◽  
Male Sterile ◽  
Male Sterile Plant ◽  
B Genome ◽  
Aegilops Longissima ◽  
Genome Donor

Initial attempts to substitute euploid nuclei of Triticum turgidum L. or T. aestivum L. into Aegilops longissima S. &L. cytoplasm failed because an alien chromosome remained fixed in the Triticum nucleus. The alien chromosome had gene(s) conditioning sporophytic sterility (also known as the gameticidal or Cuckoo effect). Subsequently, an exceptional 29-chromosome, male-sterile plant with spontaneously improved female fertility was used as a source of Ae. longissima cytoplasm, and a fully fertile alloplasmic common wheat 'Selkirk' line was developed. However, alloplasmic 'Selkirk' crossed with durum wheat as a recurrent male parent did not produce euploid plants. Instead, chromosome 1D or telocentric 1DL of 'Selkirk' was retained and male-sterile plants with 29 chromosomes were obtained. They set two seed types: a few that were plump and viable (PVi) and a large number that were shrivelled and inviable (SIv). The 1DL was deleted by crossing these plants to T. timopheevii, backcrossing the F1's to T. timopheevii, and repeatedly backcrossing the timopheevii-like plants to durum as the recurrent male parent. The resulting euploid durum plants with Ae. longissima cytoplasm were male sterile and set a 1:1 ratio of PVi and SIv seeds. Thus, a species cytoplasm specific (scs) gene of T. timopheevii was transferred to durum and caused male sterility and abortion of embryos lacking this gene. In conclusion, (i) the scs gene was expressed as a dominant sterility gene, restored seed viability, and partial compatibility between the durum nucleus and Ae. longissima cytoplasm and (ii) a scs gene on 1DL also caused dominant sterility in durum but not in alloplasmic common wheat. Hence, alien scs homoeoallele(s) conditioned sterility and seed abortion in alloplasmic durum but not in T. aestivum and T. timopheevii.Key words: interspecific nucleocytoplasmic genetics, sporophytically controlled sterility, B-genome donor, scs gene.

Additional evidence implicating Triticum searsii as the B-genome donor to wheat

1984 ◽  
Vol 22 (1-2) ◽  
pp. 37-50 ◽  
Author(s):  
J. Nath ◽  
James J. Hanzel ◽  
James P. Thompson ◽  
James W. McNay
Keyword(s):  
B Genome ◽  
Genome Donor

EVIDENCE FOR AEGILOPS SHARONENSIS EIG AS THE DONOR OF THE B GENOME OF WHEAT

Genetics ◽  
1981 ◽  
Vol 99 (3-4) ◽  
pp. 495-512
Author(s):  
U Kushnir ◽  
G M Halloran
Keyword(s):  
Triticum Turgidum ◽  
Tetraploid Wheat ◽  
Grain Morphology ◽  
B Genome ◽  
Aegilops Sharonensis ◽  
Genome Donor ◽  
Low Levels ◽  
High Level ◽  
Karyotype Morphology ◽  
Donor Species

ABSTRACT A number of lines of evidence are advanced for the candidacy of Aegilops sharonensisEig as the donor of the B genome of wheat. The cytoplasm of Ae. shuronensis iscompatible with tetraploid wheat Triticum turgidum dicoccoides,as evidenced bythe high level of chromosome pairing and fertility of the amphiploid Ae. sharonensisx T. turgidum dicoccoides. Ae. sharonensischromosomes exhibit high levels of pairing with those of the B genome of wheat in hybrids with Ph-deficient hexaploid wheat and low levels of homoeologous pairing with T. monocmcumchromosomes.——The amphidiploid between Ae. sharonensisand T. monococcumis very similar to T. turgidum dicoccoidesin spike, spikelet and grain morphology. The karyotype of Ae. sharonensisresembles more closely that of extrapolated Bgenome karyotypes of wheat than do the karyotypes of other proposed B-genome donor species of Aegilops. Because of distinctiveness in cytological aftinity and karyotype morphology between Ae. sharonensisand Ae. longissima,a separate genome symbol Sshis proposed for the former species.

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.

Phylogenetic reconstruction based on low copy DNA sequence data in an allopolyploid: The B genome of wheat

Genome ◽  
1999 ◽  
Vol 42 (2) ◽  
pp. 351-360 ◽  
Author(s):  
Nancy K Blake ◽  
Ben R Lehfeldt ◽  
Matt Lavin ◽  
Luther E Talbert
Keyword(s):  
Dna Sequences ◽  
Sequence Data ◽  
Phylogenetic Reconstruction ◽  
Diploid Species ◽  
Single Copy ◽  
Wheat Evolution ◽  
Polyploid Evolution ◽  
B Genome ◽  
Genome Donor ◽  
Copy Dna

Study of bread wheat (Triticum aestivum) may help to resolve several questions related to polyploid evolution. One such question regards the possibility that the component genomes of polyploids may themselves be polyphyletic, resulting from hybridization and introgression among different polyploid species sharing a single genome. We used the B genome of wheat as a model system to test hypotheses that bear on the monophyly or polyphyly of the individual constituent genomes. By using aneuploid wheat stocks, combined with PCR-based cloning strategies, we cloned and sequenced two single-copy-DNA sequences from each of the seven chromosomes of the wheat B genome and the homologous sequences from representatives of the five diploid species in section Sitopsis previously suggested as sister groups to the B genome. Phylogenetic comparisons of sequence data suggested that the B genome of wheat underwent a genetic bottleneck and has diverged from the diploid B genome donor. The extent of genetic diversity among the Sitopsis diploids and the failure of any of the Sitopsis species to group with the wheat B genome indicated that these species have also diverged from the ancestral B genome donor. Our results support monophyly of the wheat B genome.Key words: wheat evolution, phylogenetics, DNA sequencing.

scholarly journals A REASSESSMENT OF THE ORIGIN OF THE POLYPLOID WHEATS

Genetics ◽  
1974 ◽  
Vol 78 (1) ◽  
pp. 487-492
Author(s):  
Gordon Kimber
Keyword(s):  
Diploid Species ◽  
B Genome ◽  
Genome Donor ◽  
New Evidence

ABSTRACT The diploid species that donated the A and D genomes to the polyploid wheats have been recognized for some time. New evidence indicates that Triticum speltoides cannot be the B genome donor to T. turgidum or T. aestivum. T. speltoides is probably homologous to the G genome of T. timopheevii. The donor of the B genome to T. turgidum and T. aestivum is currently unrecognized.

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