Aneuploid strawberry (2n=8x+2=58) was developed from homozygous unreduced gamete (8x) produced by second division restitution in pollen

AbstractBreeding of banana is hampered by its genetic complexity, structural chromosome rearrangements and different ploidy levels. Various scientific disciplines, including cytogenetics, linkage mapping, and bioinformatics, are helpful tools in characterising cultivars and wild relatives used in crossing programs. Chromosome analysis still plays a pivotal role in studying hybrid sterility and structural and numerical variants. In this study, we describe the optimisation of the chromosome spreading protocol of pollen mother cells focusing on the effects of standard fixation methods, duration of the pectolytic enzyme treatment and advantages of fluorescence microscopy of DAPI stained cell spreads. We demonstrate the benefits of this protocol on meiotic features of five wild diploid Musa acuminata bananas and a diploid (AA) cultivar banana “Rejang”, with particular attention on pairing configurations and chromosome transmission that may be indicative for translocations and inversions. Pollen slides demonstrate regular-shaped spores except “Rejang”, which shows fertile pollen grains of different size and sterile pollen grains, suggesting partial sterility and unreduced gamete formation that likely resulted from restitutional meiotic divisions.

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Use of half-tetrad analysis to discriminate between two types of 2n egg formation in a potato haploid

Genome ◽

10.1139/g92-114 ◽

1992 ◽

Vol 35 (5) ◽

pp. 741-745 ◽

Cited By ~ 8

Author(s):

Joanna E. Werner ◽

David S. Douches ◽

Rosanna Freyre

Keyword(s):

Solanum Tuberosum L ◽

2N Gametes ◽

Breeding Value ◽

Tetrad Analysis ◽

Recombination Rates ◽

First Division Restitution ◽

Egg Formation ◽

Second Division Restitution ◽

2N Eggs ◽

Tetraploid Progeny

The ratio of the first division restitution (FDR) to second division restitution (SDR) 2n eggs was estimated in 4182t, a haploid (2n = 2x = 24) of Solanum tuberosum L. that produces 2n eggs by the two modes. The segregation of three genes previously mapped relative to their centromeres, Pgm-2 (2.0 cM), Mdh-1 (33.5 cM), and 6-Pgdh-3 (30.1 cM) was analyzed in the tetraploid offspring of a 2x × 4x cross. Based on the segregation of the Pgm-2 locus, 39.7% of the progeny originated from FDR 2n eggs and 60.3% from SDR. Segregation patterns of the two distal loci within the FDR-derived 4x subpopulation indicated that the gene–centromere recombination rate during megasporogenesis was significantly reduced for Mdh-1 when compared with a previous estimate during microsporogenesis. In the SDR-derived 4x subpopulation, the gene–centromere recombination rates for Mdh-1 and 6-Pgdh-3 were not significantly different from previous estimates. Tetraploid progeny generated from one 2x × 4x cross where the 2x parent produces 2n gametes by two modes can be used to make an unbiased comparison of the potential breeding value of FDR and SDR gametes.Key words: potato, megasporogenesis, first division restitution, second division restitution, isozyme.

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Ploidy frequencies in plants with ploidy heterogeneity: fitting a general gametic model to empirical population data

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2012.2387 ◽

2013 ◽

Vol 280 (1751) ◽

pp. 20122387 ◽

Cited By ~ 19

Author(s):

Jan Suda ◽

Tomáš Herben

Keyword(s):

Natural Populations ◽

Evolutionary Process ◽

Optimization Procedure ◽

Population Data ◽

Unreduced Gametes ◽

Unreduced Gamete ◽

Model Parameters ◽

Main Mode ◽

Ploidy Levels ◽

Polyploid Formation

Genome duplication (polyploidy) is a recurrent evolutionary process in plants, often conferring instant reproductive isolation and thus potentially leading to speciation. Outcome of the process is often seen in the field as different cytotypes co-occur in many plant populations. Failure of meiotic reduction during gametogenesis is widely acknowledged to be the main mode of polyploid formation. To get insight into its role in the dynamics of polyploidy generation under natural conditions, and coexistence of several ploidy levels, we developed a general gametic model for diploid–polyploid systems. This model predicts equilibrium ploidy frequencies as functions of several parameters, namely the unreduced gamete proportions and fertilities of higher ploidy plants. We used data on field ploidy frequencies for 39 presumably autopolyploid plant species/populations to infer numerical values of the model parameters (either analytically or using an optimization procedure). With the exception of a few species, the model fit was very high. The estimated proportions of unreduced gametes (median of 0.0089) matched published estimates well. Our results imply that conditions for cytotype coexistence in natural populations are likely to be less restrictive than previously assumed. In addition, rather simple models show sufficiently rich behaviour to explain the prevalence of polyploids among flowering plants.

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Transcriptome Analysis of Young Ovaries Reveals Candidate Genes Involved in Gamete Formation in Lantana camara

Plants ◽

10.3390/plants8080263 ◽

2019 ◽

Vol 8 (8) ◽

pp. 263 ◽

Cited By ~ 1

Author(s):

Ze Peng ◽

Krishna Bhattarai ◽

Saroj Parajuli ◽

Zhe Cao ◽

Zhanao Deng

Keyword(s):

Candidate Genes ◽

De Novo ◽

Transcriptome Assembly ◽

Gene Families ◽

Unreduced Gametes ◽

Lantana Camara ◽

Unreduced Gamete ◽

Genomic Resources ◽

Gamete Formation ◽

Gamete Production

Lantana (Lantana camara L., Verbenaceae) is an important ornamental crop, yet can be a highly invasive species. The formation of unreduced female gametes (UFGs) is a major factor contributing to its invasiveness and has severely hindered the development of sterile cultivars. To enrich the genomic resources and gain insight into the genetic mechanisms of UFG formation in lantana, we investigated the transcriptomes of young ovaries of two lantana genotypes, GDGHOP-36 (GGO), producing 100% UFGs, and a cultivar Landmark White Lantana (LWL), not producing UFGs. The de novo transcriptome assembly resulted in a total of 90,641 unique transcript sequences with an N50 of 1692 bp, among which, 29,383 sequences contained full-length coding sequences (CDS). There were 214 transcripts associated with the biological processes of gamete production and 10 gene families orthologous to genes known to control unreduced gamete production in Arabidopsis. We identified 925 transcription factor (TF)-encoding sequences, 91 nucleotide-binding site (NBS)-containing genes, and gene families related to drought/salt tolerance and allelopathy. These genomic resources and candidate genes involved in gamete formation will be valuable for developing new tools to control the invasiveness in L. camara, protect native lantana species, and understand the formation of unreduced gametes in plants.

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CHROMOSOMAL INSTABILITY IN A HYBRID BETWEEN HORDEUM VULGARE AND SECALE VAVILOVII

Canadian Journal of Genetics and Cytology ◽

10.1139/g82-021 ◽

1982 ◽

Vol 24 (2) ◽

pp. 207-212 ◽

Cited By ~ 8

Author(s):

George Fedak ◽

Chiharu Nakamura

Keyword(s):

Hordeum Vulgare ◽

Chromosome Number ◽

Chiasma Frequency ◽

Chromosomal Instability ◽

Chromosome Instability ◽

Somatic Tissue ◽

Unreduced Gamete ◽

Hordeum Vulgare L ◽

The Mean

A hybrid was obtained between Hordeum vulgare L. cv. Betzes (2n = 2x = 14) and Secale vavilovii [Nürn. (2n = 2x = 14)] in which chromosome instability was observed in somatic and meiotic tissues. In somatic tissue the chromosomes per cell varied from 7 to 24 with a mean of 19.7. Similarly in meiotic tissue the chromosome number varied from 14 to 26 with a mean of 18.3. The mean chiasma frequency was 12.9 consisting of an average Ml configuration of 0.02IV + 0.3III + 6.68II + 3.92I. It was concluded that the hybrid was derived from the union of an unreduced gamete from Betzes barley with a normal gamete from S. vavilovii.

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Unreduced Megagametophyte Production in Lemon Occurs via Three Meiotic Mechanisms, Predominantly Second-Division Restitution

Frontiers in Plant Science ◽

10.3389/fpls.2017.01211 ◽

2017 ◽

Vol 8 ◽

Cited By ~ 14

Author(s):

Houssem Rouiss ◽

José Cuenca ◽

Luis Navarro ◽

Patrick Ollitrault ◽

Pablo Aleza

Keyword(s):

Second Division Restitution

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Coenocytism, ameiosis, and chromosome diminution in intergeneric hybrids in the perennial Triticeae

Genome ◽

10.1139/g88-124 ◽

1988 ◽

Vol 30 (5) ◽

pp. 766-775 ◽

Cited By ~ 7

Author(s):

Richard R.-C. Wang

Keyword(s):

Intergeneric Hybrid ◽

Chromosome Elimination ◽

Intergeneric Hybrids ◽

Pollen Grain ◽

Unreduced Gamete ◽

Pollen Mother Cells ◽

Psathyrostachys Juncea ◽

Hybrid Plants ◽

Mother Cells ◽

Pollen Grain Wall

Three different pathways of ameiotic microsporogenesis were observed in some intergeneric hybrids of the perennial Triticeae grasses. In one of the hybrids between Pseudoroegneria spicata ssp. inermis and Psathyrostachys juncea, pollen mother cells remained as premeiotic interphase cells when the pollen grain wall started to form. The microspores in such an ameiotic plant are presumably unreduced. Coenocyte formation coupled with ameiosis occurred in two hybrid plants of Psathyrostachys huashanica × Secale montanum. Less than 10% of the pollen mother cells had one nucleus. An average of 4.44 nuclei, ranging from 1 to 25 per pollen mother cell, was observed. The nuclei in coenocytes remained unfused when the pollen grain wall was formed. Nucleus splitting followed by cytoplasmic budding or cleavage, possibly a process of chromosome diminution or elimination, replaced meiotic divisions in most of the pollen mother cells in one plant of Leymus angustus × Hordeum bulbosum and two plants of Thinopyrum elongatum × Psathyrostachys juncea. It is evident that these meiotic abnormalities are under genetic control. Probable locations for these genes controlling these phenomena are suggested.Key words: coenocyte, ameiosis, chromosome diminution, chromosome elimination, microsporogenesis, unreduced gamete, polyploidy, intergeneric hybrid.

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