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.

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.

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.

The evolution of polyploid wheats: identification of the A genome donor species

Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Jan Dvořák ◽  
Pantaleo di Terlizzi ◽  
Hong-Bin Zhang ◽  
Paolo Resta
Keyword(s):  
Nucleotide Sequence ◽  
Chromosome Pairing ◽  
Hexaploid Wheat ◽  
Triticum Turgidum ◽  
Nucleotide Sequences ◽  
The Other ◽  
Genome Donor ◽  
A Genome ◽  
Sequence Profiles ◽  
Donor Species

Cytogenetic work has shown that the tetraploid wheats, Triticum turgidum and T. timopheevii, and the hexaploid wheat T. aestivum have one pair of A genomes, whereas hexaploid T. zhukovskyi has two. Variation in 16 repeated nucleotide sequences was used to identify sources of the A genomes. The A genomes of T. turgidum, T. timopheevii, and T. aestivum were shown to be contributed by T. urartu. Little divergence in the repeated nucleotide sequences was detected in the A genomes of these species from the genome of T. urartu. In T. zhukovskyi one A genome was contributed by T. urartu and the other was contributed by T. monococcum. It is concluded that T. zhukovskyi originated from hybridization of T. timopheevii with T. monococcum. The repeated nucleotide sequence profiles in the A genomes of T. zhukovskyi showed reduced correspondence with those in the genomes of both ancestral species, T. urartu and T. monococcum. This differentiation is attributed to heterogenetic chromosome pairing and segregation among chromosomes of the two A genomes in T. zhukovskyi.Key words: phylogeny, Triticum, Aegilops, repeated nucleotide sequences.

High world sugar prices: is Asia’s production cycle to blame?

2010 ◽  
pp. 169-173
Author(s):  
Martin Todd
Keyword(s):  
Supply Chain ◽  
Supply And Demand ◽  
Production Cycle ◽  
Low Levels ◽  
High Level ◽  
High World

The current high world sugar prices reflect a major imbalance between global supply and demand, which has reduced stocks to very low levels. Although it remains to be seen whether prices will rise much above current values, it is clear that the supply chain will remain stretched throughout 2010 and this will help to maintain prices at a high level.

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

Plants ◽  
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.

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

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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