Mapping of a chromosome pairing gene and 5S rRNA genes in Triticum aestivum L. by a spontaneous deletion in chromosome arm 5Bp

A deletion in the p arm of chromosome 5B of Triticum aestivum L. cv. Chinese Spring was identified by C-banding during the production of disomic substitutions of 6B of Aegilops longissima Schweinf. et Muschl. for chromosome 5B of cv. Chinese Spring. The deletion was terminal with a breakpoint just proximal to the interstitial C-band. The degree of metaphase I chromosome pairing in plants homozygous for the deletion indicated that the chromosome pairing promoting gene known to be in the p arm of chromosome 5B is located in the deleted portion of that arm. Additionally, all of the 5S ribosomal RNA genes known to exist on arm 5Bp were mapped to this deleted portion.Key words: C-banding, 5S rRNA genes, Triticum, Aegilops chromosome aberration.

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GENETIC REGULATION OF HETEROGENETIC CHROMOSOME PAIRING IN POLYPLOID SPECIES OF THE GENUS TRITICUM sensu lato

Canadian Journal of Genetics and Cytology ◽

10.1139/g82-007 ◽

1982 ◽

Vol 24 (1) ◽

pp. 57-82 ◽

Cited By ~ 24

Author(s):

Patrick E. McGuire ◽

Jan Dvořák

Keyword(s):

Triticum Aestivum ◽

Chromosome Pairing ◽

Chinese Spring ◽

Genetic Regulation ◽

Triticum Aestivum L ◽

Polyploid Species ◽

D Genome ◽

Chromosome 5B ◽

A Genome

Polyploid species of Triticum sensu lato were crossed with Triticum aestivum L. em. Thell. cv. Chinese Spring monotelodisomics or ditelosomics that were monosomic for chromosome 5B. Progeny from these crosses were either euploid, nullisomic for 5B, monotelosomic for a given Chinese Spring chromosome, or nullisomic for 5B and monotelosomic simultaneously. The Chinese Spring telosome in the hybrids permitted the evaluation of autosyndesis of chromosomes of the tested species. In addition, several Chinese Spring eu- and aneuhaploids were produced. Genotypes of T. cylindricum Ces., T. juvenale Thell., T. triunciale (L.) Raspail, T. ovatum (L.) Raspail, T. columnare (Zhuk.) Morris et Sears, T. triaristatum (Willd.) Godr. et Gren., and T. rectum (Zhuk.) comb. nov. were all shown to have suppressive effects on heterogenetic pairing in hybrids lacking 5B or 3AS, whereas T. kotschyi (Boiss.) Bowden had no effect. It was concluded that diploid-like meiosis in these species is due to genetic regulation. A number of these genotypes promoted heterogenetic pairing in the presence of 5B. A model is presented to explain this dichotomous behavior of the tested genotypes. Monotelosomic-3AL haploids had a greater amount of pairing than did euhaploid Chinese Spring, which substantiated the presence of a pairing suppressor(s) on the 3AS arm. Evidence is presented that shows that T. juvenale does not have a genome homologous with the D genome of T. aestivum.

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CHROMOSOME DIFFERENTIATION IN POLYPLOID SPECIES OF ELYTRIGIA, WITH SPECIAL REFERENCE TO THE EVOLUTION OF DIPLOID-LIKE CHROMOSOME PAIRING IN POLYPLOID SPECIES

Canadian Journal of Genetics and Cytology ◽

10.1139/g81-031 ◽

1981 ◽

Vol 23 (2) ◽

pp. 287-303 ◽

Cited By ~ 21

Author(s):

J. Dvořák

Keyword(s):

Triticum Aestivum ◽

Special Reference ◽

Normal Level ◽

Chromosome Pairing ◽

Chinese Spring ◽

Triticum Aestivum L ◽

Polyploid Species ◽

Chromosome Differentiation

Triticum aestivum L. em Thell ditelosomics 7AL and 7DS and T. aestivum-Elytrigia elongata (Host) Holub (2n = 2x = 14) ditelosomic additions were crossed with "E. elongata 4x" (2n = 4x = 28), E. caespitosa (C. Koch) Nevski (2n = 4x = 28), and E. intermedia (Host) Nevski (2n = 6x = 42). The effect of each Elytrigia genotype on homoeologous (heterogenetic) chromosome pairing was assessed by comparing the pairing frequencies of T. aestivum cv. Chinese Spring telosomes 7AL and 7DS in the hybrids with the pairing frequency of telosome 7AL in haploid Chinese Spring. The genotype of "E. elongata 4x" had no effect on heterogenetic pairing in the hybrids. Although some genotypes of E. caespitosa and E. intermedia promoted heterogenetic pairing in the hybrids, others had no effect. Telosome VS of E. elongata interacted in a complementary fashion with the genotype of "E. elongata 4x," but not with the genotypes of Chinese Spring and E. caespitosa, and it promoted heterogenetic pairing. In hybrids in which the wheat diploidizing genes were active at the normal level, the E. elongata telosomes paired with chromosomes of "E. elongata 4x" in 5.8% to 24.6% of the cells, with chromosomes of E. caespitosa in 0.0% to 1.0% of the cells, and with chromosomes of E. intermedia in 0.0% to 2.8% of the cells. A model of chromosome differentiation is discussed and special attention is devoted to the origin of diploid-like pairing in polyploid species.

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EFFECT OF RYE ON HOMOEOLOGOUS CHROMOSOME PAIRING IN WHEAT × RYE HYBRIDS

Canadian Journal of Genetics and Cytology ◽

10.1139/g77-059 ◽

1977 ◽

Vol 19 (3) ◽

pp. 549-556 ◽

Cited By ~ 32

Author(s):

J. Dvořák

Keyword(s):

Triticum Aestivum ◽

Chromosome Pairing ◽

Chinese Spring ◽

Triticum Aestivum L ◽

Homoeologous Chromosome ◽

Wheat Genotype ◽

Hybrid Plants ◽

Homoeologous Chromosome Pairing ◽

Secale Cereale L ◽

Polygenic System

The number of chiasmata per cell at metaphase I was scored in eight haploid plants of Triticum aestivum L. emend. Thell. cv. 'Chinese Spring' and 100 hybrid plants of Chinese Spring × Secale cereale L. Mean chiasma frequency per cell ranged from 0.00 to 3.59 in the hybrids and from 0.17 to 0.35 in the haploids. Since the same wheat genotype was present in both the haploids and hybrids, it is concluded that some of the rye genotypes promoted homoeologous chromosome pairing. The absence of distinct segregation classes among the hybrids suggests that these genes constitute a polygenic system.

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Metaphase I pairing of deficient chromosomes and genetic mapping of deficiency breakpoints in common wheat

Genome ◽

10.1139/g91-085 ◽

1991 ◽

Vol 34 (4) ◽

pp. 553-560 ◽

Cited By ~ 38

Author(s):

C. A. Curtis ◽

A. J. Lukaszewski ◽

M. Chrzastek

Keyword(s):

Triticum Aestivum ◽

Genetic Mapping ◽

Chromosome Pairing ◽

Triticum Aestivum L ◽

Genetic Distances ◽

Homologous Chromosomes ◽

Transmission Rates ◽

Chromosome 5B ◽

Pairing Initiation ◽

Metaphase I

Metaphase I pairing of deficient chromosomes was analyzed in a set of 'Chinese Spring' (CS) wheat (Triticum aestivum L. em. Thell.) plants with varying lengths of deficiencies in the long arm of chromosome 4A (6, 8, 11, 17, 23, 34, 36, 39, and 50% missing), the long arm of chromosome 5B (49% missing), and the long arm of chromosome 2B (33% missing). Pairing in homologous chromosomes between deficient and complete arms was greatly reduced even by small differences in arm length. In deficiency homozygotes and in an isochromosome derived from a deficient 4AL arm, pairing of the two deficient arms was high and approached that of two complete arms. In plants where deficient and complete arms competed for pairing partners, pairing was exclusively between arms of the same length. These results suggest that in wheat, pairing initiation sites are distributed throughout at least the distal halves of the arms and that the alignment of telomeres may be critical for pairing success. Genetic mapping of the deficiency breakpoints was confounded by misdivision of unpaired chromosomes and abnormal transmission rates. Genetic distances between centromeres and breakpoints appeared to be proportional to metaphase I pairing frequencies.Key words: bread wheat, deficiency, chromosome pairing competition, mapping, telomere, pairing initiation.

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INDUCED PAIRING BETWEEN A WHEAT (TRITICUM AESTIVUM) AND AN AGROPYRON ELONGATUM CHROMOSOME

Canadian Journal of Genetics and Cytology ◽

10.1139/g81-006 ◽

1981 ◽

Vol 23 (1) ◽

pp. 49-56 ◽

Cited By ~ 7

Author(s):

Y. Yasumuro ◽

R. Morris ◽

D. C. Sharma ◽

J. W. Schmidt

Keyword(s):

Triticum Aestivum ◽

Chinese Spring ◽

Wheat Chromosome ◽

Leaf Rust Resistance ◽

Triticum Aestivum L ◽

Puccinia Graminis ◽

Agropyron Elongatum ◽

Chromosome 5B ◽

Transfer Genes ◽

I Cells

A study was initiated to transfer genes for stem- and leaf-rust resistance from a chromosome (designated 6Ag) of Agropyron elongatum (Host) Beauv to a homoeologous chromosome (6D) of wheat (Triticum aestivum L. aestivum group) by inducing pairing between 6Ag and 6D in the absence of the Ph gene on wheat chromosome 5B. Plants monosomic for SB, 6D and 6Ag were crossed with Chinese Spring nullisomic-5B tetrasomic-5D or with Chinese Spring monosomic or trisomic for SB with an induced mutation, phlb, of the Ph locus. Tests of 282 offspring in the seedling stage for reaction to the stem rust pathogen, Puccinia graminis Pers. f. sp. tritici Eriks. &E. Henn. race 56 or 15B-2, were used to identify 70 plants with 6Ag, which was transmitted through 25% of the female gametes. Meiotic observations on 51 of these plants indicated that six were monosomic for 6D and 6Ag, but lacked an entire 5B or had 5B with the phlb mutation. The frequency of metaphase I cells with pairing between 6D and 6Ag averaged 4.94% in three plants that were nullisomic for 5B and 2.48% in two plants that had a single dose of 5B with the phlb mutation.

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REDUCTION OF CHROMOSOME PAIRING BY A SPONTANEOUS MUTATION ON CHROMOSOMAL ARM 5DL OF TRITICUM AESTIVUM

Canadian Journal of Genetics and Cytology ◽

10.1139/g80-062 ◽

1980 ◽

Vol 22 (4) ◽

pp. 569-575 ◽

Cited By ~ 6

Author(s):

Wanda S. Viegas ◽

T. Mello-Sampayo ◽

Moshe Feldman ◽

Lydia Avivi

Keyword(s):

Triticum Aestivum ◽

Chromosome Pairing ◽

Secale Cereale ◽

Chinese Spring ◽

Spontaneous Mutation ◽

Triticum Aestivum L ◽

Homoeologous Chromosome ◽

Homoeologous Chromosome Pairing ◽

Promoter Allele

In a plant of Triticum aestivum L. em. Thell. cultivar Chinese Spring which was disomic for a mutant isochromosome of the long arm of chromosome 5D (di-isosomic 5DLM), partial chromosome asynapsis was detected at meiosis. Chromosome pairing in F1 hybrids from crosses of T. aestivum plants carrying the mutant isochromosome with Secale cereale, an intermediate pairing line of T. longissimum and with T. sharonensis disclosed that 5DLM carried a gene that reduced homoeologous chromosome pairing. This gene, designated Ph3 is less potent than its assumed homoeoallele on chromosomal arm 5BL, i.e., Ph1. The possibility of Ph1 being transferred from 5BL to 5DL through homoeologous chromosome pairing and recombination was discarded. Rather, it seems more likely that this allele resulted from a spontaneous mutation of the pairing-promoter allele known to be located on 5DL.

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LATENT NONSTRUCTURAL DIFFERENTIATION AMONG HOMOLOGOUS CHROMOSOMES AT THE DIPLOID LEVEL: CHROMOSOME 6Be OF AEGILOPS LONGISSIMA

Genetics ◽

10.1093/genetics/114.2.579 ◽

1986 ◽

Vol 114 (2) ◽

pp. 579-592

Author(s):

Rama S Kota ◽

Patrick E McGuire ◽

Jan Dvořák

Keyword(s):

Chromosome Pairing ◽

Chinese Spring ◽

Constitutive Heterochromatin ◽

Diploid Species ◽

Triticum Aestivum L ◽

Homologous Chromosomes ◽

B Genome ◽

Aegilops Longissima ◽

Chinese Spring Wheat ◽

Diploid Level

ABSTRACT Previous work has shown that chromosome pairing at metaphase I (MI) of wheat homologous chromosomes from different inbred lines (heterohomologous chromosomes) is reduced relative to that between homologous chromosomes within an inbred line (euhomologous chromosomes). In order to determine if a potential for this phenomenon exists in diploid species closely related to the wheat B genome, MI chromosome pairing was investigated between euhomologous and heterohomologous 6Be (=6Se) chromosomes, each from a different population of Aegilops longissima Schweinf. et Muschl. (2n = 2x = 14) substituted for chromosome 6B of Chinese Spring wheat (Triticum aestivum L., 2n = 6x = 42). Euhomologous and heterohomologous monotelodisomics, i.e., plants with one complete chromosome 6Be and a telosome of either 6Bep or 6Beq, were constructed in the isogenic background of Chinese Spring. Pairing at MI of the Ae. longissima chromosomes was reduced in heterohomologous monotelodisomics compared to that in the corresponding euhomologous monotelodisomics. The remaining 20 pairs of Chinese Spring chromosomes paired equally well in the euhomologous and heterohomologous monotelodisomics. Thus, the cause of the reduced pairing must reside specifically in the Ae. longissima heterohomologues. In the hybrids between the Ae. longissima lines that contributed the substituted chromosomes, pairing between the heterohomologous chromosomes was normal and did not differ from that of the euhomologous chromosomes. These data provide evidence that a potential for reduced pairing between the heterohomologues is present in the diploid species, but is expressed only in the polyploid wheat genetic background. The reduction in heterohomologous chromosome pairing was greater in the p arm than in the q arm, exactly as in chromosome 6B of wheat. It is concluded that the reduced pairing between Ae. longissima heterohomologues has little to do with constitutive heterochromatin. The value of chromosome pairing as an unequivocal means of determining the origin of genomes in polyploid plants is questioned.

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A rapid technique for substituting alien chromosomes into Triticum aestivum and determining their homoeology

Canadian Journal of Genetics and Cytology ◽

10.1139/g85-081 ◽

1985 ◽

Vol 27 (5) ◽

pp. 549-558 ◽

Cited By ~ 9

Author(s):

Rama S. Kota ◽

Jan Dvořák

Keyword(s):

In Situ Hybridization ◽

Chinese Spring ◽

Wheat Chromosome ◽

Rrna Genes ◽

Gene Probe ◽

Rapid Technique ◽

C Banding ◽

Aegilops Longissima ◽

26S Rrna

A rapid technique is described for the production of a disomic substitution of an alien chromosome for a selected wheat chromosome directly from the amphiploid. Determination of homoeology between the chromosomes involved is a by-product of this technique. The technique involves the production of a nullisomic amphiploid from a cross between a wheat mono-telosomic and a diploid species and recurrently backcrossing it as a male twice to the monotelosomic. Disomic and ditelosomic substitutions are then selected upon self-pollination. The utility of this technique is shown by producing a large number of disomic and ditelosomic substitutions of an Aegilops longissima chromosome homoeologous to wheat chromosome 6B from two populations of Ae. longissima. The incorporated Ae. longissima chromosome was characterized by C-banding and in situ hybridization of an 18S–26S rRNA gene probe. The chromosome differs in C-band pattern from chromosome 6B of 'Chinese Spring' and does not pair with the 6Bp telosome at metaphase I. It also differs from 'Chinese Spring' chromosome 6B by having the 18S–26S rRNA compound locus in the long arm.Key words: disomic substitution, homoeology, C-banding, in-situ hybridization, rRNA genes, gene synteny, Triticum, Aegilops longissima.

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Ribosomal DNA localization on Lathyrus species chromosomes by FISH

Journal of Genetic Engineering and Biotechnology ◽

10.1186/s43141-020-00075-1 ◽

2020 ◽

Vol 18 (1) ◽

Author(s):

Hoda B. M. Ali ◽

Samira A. Osman

Keyword(s):

Genome Mapping ◽

Chromosome Complement ◽

5S Rdna ◽

Rdna Locus ◽

5S Rrna ◽

Rrna Genes ◽

45S Rdna ◽

Metaphase Chromosomes ◽

Lathyrus Odoratus ◽

5S Rrna Genes

Abstract Background Fluorescence In Situ Hybridization (FISH) played an essential role to locate the ribosomal RNA genes on the chromosomes that offered a new tool to study the chromosome structure and evolution in plant. The 45S and 5S rRNA genes are independent and localized at one or more loci per the chromosome complement, their positions along chromosomes offer useful markers for chromosome discriminations. In the current study FISH has been performed to locate 45S and 5S rRNA genes on the chromosomes of nine Lathyrus species belong to five different sections, all have chromosome number 2n=14, Lathyrus gorgoni Parl, Lathyrus hirsutus L., Lathyrus amphicarpos L., Lathyrus odoratus L., Lathyrus sphaericus Retz, Lathyrus incospicuus L, Lathyrus paranensis Burkart, Lathyrus nissolia L., and Lathyrus articulates L. Results The revealed loci of 45S and 5S rDNA by FISH on metaphase chromosomes of the examined species were as follow: all of the studied species have one 45S rDNA locus and one 5S rDNA locus except L. odoratus L., L. amphicarpos L. and L. sphaericus Retz L. have two loci of 5S rDNA. Three out of the nine examined species have the loci of 45S and 5S rRNA genes on the opposite arms of the same chromosome (L. nissolia L., L. amphicarpos L., and L. incospicuus L.), while L. hirsutus L. has both loci on the same chromosome arm. The other five species showed the loci of the two types of rDNA on different chromosomes. Conclusion The detected 5S and 45S rDNA loci in Lathyrus could be used as chromosomal markers to discriminate the chromosome pairs of the examined species. FISH could discriminate only one chromosome pair out of the seven pairs in three species, in L. hirsutus L., L. nissolia L. and L. incospicuus L., and two chromosome pairs in five species, in L. paranensis Burkart, L. odoratus L., L. amphicarpos L., L. gorgoni Parl. and L. articulatus L., while it could discriminate three chromosome pairs in L. sphaericus Retz. these results could contribute into the physical genome mapping of Lathyrus species and the evolution of rDNA patterns by FISH in the coming studies in future.

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