19 results on '"Jenczewski, Eric"'
Search Results
2. Reducing MSH4 copy number prevents meiotic crossovers between non-homologous chromosomes in Brassica napus.
- Author
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Gonzalo A, Lucas MO, Charpentier C, Sandmann G, Lloyd A, and Jenczewski E
- Subjects
- Chromosomes, Plant metabolism, DNA Copy Number Variations, Homologous Recombination, Brassica napus genetics, Chromosome Segregation genetics, Crossing Over, Genetic genetics, Meiosis genetics, MutS Proteins genetics, Polyploidy
- Abstract
In allopolyploids, correct chromosome segregation requires suppression of non-homologous crossovers while levels of homologous crossovers are ensured. To date, no mechanism able to specifically inhibit non-homologous crossovers has been described in allopolyploids other than in bread wheat. Here, we show that reducing the number of functional copies of MSH4, an essential gene for the main crossover pathway, prevents non-homologous crossovers in allotetraploid Brassica napus. We show that non-homologous crossovers originate almost exclusively from the MSH4-dependent recombination pathway and that their numbers decrease when MSH4 returns to single copy in B. napus; by contrast, homologous crossovers remain unaffected by MSH4 duplicate loss. We also demonstrate that MSH4 systematically returns to single copy following numerous independent polyploidy events, a pattern that is probably not by chance. These results suggest that stabilization of allopolyploid meiosis can be enhanced by loss of a key meiotic recombination gene.
- Published
- 2019
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- View/download PDF
3. Assessing the Response of Small RNA Populations to Allopolyploidy Using Resynthesized Brassica napus Allotetraploids.
- Author
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Martinez Palacios P, Jacquemot MP, Tapie M, Rousselet A, Diop M, Remoué C, Falque M, Lloyd A, Jenczewski E, Lassalle G, Chévre AM, Lelandais C, Crespi M, Brabant P, Joets J, and Alix K
- Subjects
- Brassica napus metabolism, DNA Transposable Elements, Brassica napus genetics, Genetic Speciation, RNA, Small Untranslated metabolism, Tetraploidy
- Abstract
Allopolyploidy, combining interspecific hybridization with whole genome duplication, has had significant impact on plant evolution. Its evolutionary success is related to the rapid and profound genome reorganizations that allow neoallopolyploids to form and adapt. Nevertheless, how neoallopolyploid genomes adapt to regulate their expression remains poorly understood. The hypothesis of a major role for small noncoding RNAs (sRNAs) in mediating the transcriptional response of neoallopolyploid genomes has progressively emerged. Generally, 21-nt sRNAs mediate posttranscriptional gene silencing by mRNA cleavage, whereas 24-nt sRNAs repress transcription (transcriptional gene silencing) through epigenetic modifications. Here, we characterize the global response of sRNAs to allopolyploidy in Brassica, using three independently resynthesized Brassica napus allotetraploids originating from crosses between diploid Brassica oleracea and Brassica rapa accessions, surveyed at two different generations in comparison with their diploid progenitors. Our results suggest an immediate but transient response of specific sRNA populations to allopolyploidy. These sRNA populations mainly target noncoding components of the genome but also target the transcriptional regulation of genes involved in response to stresses and in metabolism; this suggests a broad role in adapting to allopolyploidy. We finally identify the early accumulation of both 21- and 24-nt sRNAs involved in regulating the same targets, supporting a posttranscriptional gene silencing to transcriptional gene silencing shift at the first stages of the neoallopolyploid formation. We propose that reorganization of sRNA production is an early response to allopolyploidy in order to control the transcriptional reactivation of various noncoding elements and stress-related genes, thus ensuring genome stability during the first steps of neoallopolyploid formation., (© The Author(s) 2019. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.)
- Published
- 2019
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4. Homoeologous exchanges cause extensive dosage-dependent gene expression changes in an allopolyploid crop.
- Author
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Lloyd A, Blary A, Charif D, Charpentier C, Tran J, Balzergue S, Delannoy E, Rigaill G, and Jenczewski E
- Subjects
- Gene Expression, Organ Specificity, Polyploidy, Recombination, Genetic, Sequence Analysis, RNA, Brassica napus genetics, Gene Dosage, Genetic Variation, Genome, Plant genetics
- Abstract
Structural variation is a major source of genetic diversity and an important substrate for selection. In allopolyploids, homoeologous exchanges (i.e. between the constituent subgenomes) are a very frequent type of structural variant. However, their direct impact on gene content and gene expression had not been determined. Here, we used a tissue-specific mRNA-Seq dataset to measure the consequences of homoeologous exchanges (HE) on gene expression in Brassica napus, a representative allotetraploid crop. We demonstrate that expression changes are proportional to the change in gene copy number triggered by the HEs. Thus, when homoeologous gene pairs have unbalanced transcriptional contributions before the HE, duplication of one copy does not accurately compensate for loss of the other and combined homoeologue expression also changes. These effects are, however, mitigated over time. This study sheds light on the origins, timing and functional consequences of homeologous exchanges in allopolyploids. It demonstrates that the interplay between new structural variation and the resulting impacts on gene expression, influences allopolyploid genome evolution., (© 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.)
- Published
- 2018
- Full Text
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5. Crossover rate between homologous chromosomes and interference are regulated by the addition of specific unpaired chromosomes in Brassica.
- Author
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Suay L, Zhang D, Eber F, Jouy H, Lodé M, Huteau V, Coriton O, Szadkowski E, Leflon M, Martin OC, Falque M, Jenczewski E, Paillard S, and Chèvre AM
- Subjects
- Aneuploidy, Chromosome Pairing, Hybridization, Genetic, In Situ Hybridization, Fluorescence, Brassica napus genetics, Chromosomes, Plant metabolism, Homologous Recombination
- Abstract
Recombination is a major mechanism generating genetic diversity, but the control of the crossover rate remains a key question. In Brassica napus (AACC, 2n = 38), we can increase the homologous recombination between A genomes in AAC hybrids. Hypotheses for this effect include the number of C univalent chromosomes, the ratio between univalents and bivalents and, finally, which of the chromosomes are univalents. To test these hypotheses, we produced AA hybrids with zero, one, three, six or nine additional C chromosomes and four different hybrids carrying 2n = 32 and 2n = 35 chromosomes. The genetic map lengths for each hybrid were established to compare their recombination rates. The rates were 1.4 and 2.7 times higher in the hybrids having C6 or C9 alone than in the control (0C). This enhancement reached 3.1 and 4.1 times in hybrids carrying six and nine C chromosomes, and it was also higher for each pair of hybrids carrying 2n = 32 or 2n = 35 chromosomes, with a dependence on which chromosomes remained as univalents. We have shown, for the first time, that the presence of one chromosome, C9 , affects significantly the recombination rate and reduces crossover interference. This result will have fundamental implications on the regulation of crossover frequency., (© 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.)
- Published
- 2014
- Full Text
- View/download PDF
6. Non-random distribution of extensive chromosome rearrangements in Brassica napus depends on genome organization.
- Author
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Nicolas SD, Monod H, Eber F, Chèvre AM, and Jenczewski E
- Subjects
- Brassica napus classification, Chromosome Mapping, Crosses, Genetic, Diploidy, Evolution, Molecular, Fertility genetics, Genetic Loci genetics, Genetic Variation, Haploidy, Linkage Disequilibrium, Meiosis genetics, Models, Genetic, Phylogeny, Polyploidy, Brassica napus genetics, Chromosomes, Plant genetics, Gene Rearrangement, Genome, Plant genetics
- Abstract
Chromosome rearrangements are common, but their dynamics over time, mechanisms of occurrence and the genomic features that shape their distribution and rate are still poorly understood. We used allohaploid Brassica napus (AC, n = 19) as a model to analyze the effect of genomic features on the formation and diversity of meiotically driven chromosome rearrangements. We showed that allohaploid B. napus meiosis leads to extensive new structural diversity. Almost every allohaploid offspring carried a unique combination of multiple rearrangements throughout the genome, and was thus structurally differentiated from both its haploid parent and its sister plants. This large amount of genome reshuffling was remarkably well-tolerated in the heterozygous state, as neither male nor female fertility were strongly reduced, and meiosis behavior was normal in most cases. We also used a quantitative statistical model, which accounted for 75% of the observed variation in rearrangement rates, to show that the distribution of meiotically driven chromosome rearrangements was not random but was shaped by three principal genomic features. In descending order of importance, the rate of marker loss increased strongly with genetic distance from the centromere, the degree of collinearity between chromosomes, and the genome of origin (A < C). Overall, our results demonstrate that B. napus accumulates a large number of genetic changes, but these rearrangements are not randomly distributed in the genome. The structural genetic diversity produced by the allohaploid pathway and its role in the evolution of polyploid species compared to diploid meiosis are discussed., (© 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.)
- Published
- 2012
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- View/download PDF
7. Repeated polyploidy drove different levels of crossover suppression between homoeologous chromosomes in Brassica napus allohaploids.
- Author
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Cifuentes M, Eber F, Lucas MO, Lode M, Chèvre AM, and Jenczewski E
- Subjects
- Brassica napus cytology, Meiosis, Brassica napus genetics, Chromosomes, Plant, Crossing Over, Genetic, Haploidy, Polyploidy
- Abstract
Allopolyploid species contain more than two sets of related chromosomes (homoeologs) that must be sorted during meiosis to ensure fertility. As polyploid species usually have multiple origins, one intriguing, yet largely underexplored, question is whether different mechanisms suppressing crossovers between homoeologs may coexist within the same polyphyletic species. We addressed this question using Brassica napus, a young polyphyletic allopolyploid species. We first analyzed the meiotic behavior of 363 allohaploids produced from 29 accessions, which represent a large part of B. napus genetic diversity. Two main clear-cut meiotic phenotypes were observed, encompassing a twofold difference in the number of univalents at metaphase I. We then sequenced two chloroplast intergenic regions to gain insight into the maternal origins of the same 29 accessions; only two plastid haplotypes were found, and these correlated with the dichotomy of meiotic phenotypes. Finally, we analyzed genetic diversity at the PrBn locus, which was shown to determine meiotic behavior in a segregating population of B. napus allohaploids. We observed that segregation of two alleles at PrBn could adequately explain a large part of the variation in meiotic behavior found among B. napus allohaploids. Overall, our results suggest that repeated polyploidy resulted in different levels of crossover suppression between homoeologs in B. napus allohaploids.
- Published
- 2010
- Full Text
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8. Genetic regulation of meiotic cross-overs between related genomes in Brassica napus haploids and hybrids.
- Author
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Nicolas SD, Leflon M, Monod H, Eber F, Coriton O, Huteau V, Chèvre AM, and Jenczewski E
- Subjects
- Chromosomes, Plant, Genetic Linkage, Genetic Markers, Genotype, Polyploidy, Brassica napus genetics, Genome, Plant, Haploidy, Hybridization, Genetic, Meiosis genetics, Recombination, Genetic genetics
- Abstract
Although the genetic regulation of recombination in allopolyploid species plays a pivotal role in evolution and plant breeding, it has received little recent attention, except in wheat (Triticum aestivum). PrBn is the main locus that determines the number of nonhomologous associations during meiosis of microspore cultured Brassica napus haploids (AC; 19 chromosomes). In this study, we examined the role played by PrBn in recombination. We generated two haploid x euploid populations using two B. napus haploids with differing PrBn (and interacting genes) activity. We analyzed molecular marker transmission in these two populations to compare genetic changes, which have arisen during meiosis. We found that cross-over number in these two genotypes was significantly different but that cross-overs between nonhomologous chromosomes showed roughly the same distribution pattern. We then examined genetic recombination along a pair of A chromosomes during meiosis of B. rapa x B. napus AAC and AACC hybrids that were produced with the same two B. napus genotypes. We observed significant genotypic variation in cross-over rates between the two AAC hybrids but no difference between the two AACC hybrids. Overall, our results show that PrBn changes the rate of recombination between nonhomologous chromosomes during meiosis of B. napus haploids and also affects homologous recombination with an effect that depends on plant karyotype.
- Published
- 2009
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9. Repetitive sequence-derived markers tag centromeres and telomeres and provide insights into chromosome evolution in Brassica napus.
- Author
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Pouilly N, Delourme R, Alix K, and Jenczewski E
- Subjects
- Biological Evolution, Chromosome Mapping, DNA Primers, Genetic Linkage, Polymorphism, Genetic, Retroelements, Biomarkers analysis, Brassica napus genetics, Centromere ultrastructure, Chromosomes, Plant, Repetitive Sequences, Nucleic Acid, Telomere ultrastructure
- Abstract
Centromeres and telomeres are obvious markers on chromosomes but their location on genetic maps is difficult to determine, which hampers many basic and applied research programmes. In this study, we used the characteristic distribution of five Brassica repeated sequences to generate physically anchored molecular markers tentatively tagging Brassica centromeres (84 markers) and telomeres (31 markers). These markers were mapped to the existing oilseed rape genetic map. Clusters of centromere-related loci were observed on 14 linkage groups; in addition to previous reports, we could thus provide information about the most likely position of centromeres on 17 of the 19 B. napus linkage groups. The location of centromeres on linkage groups usually matches their position on chromosomes and coincides with sites of evolutionary breakage between chromosomes. Most telomere sequence-derived markers mapped interstitially or in the proximity of centromeres; this result echoes previous reports on many eukaryote genomes and may reflect different forms of chromosome evolution. Seven telomere sequence-derived markers were located at the outermost positions of seven linkage groups and therefore probably tagged telomeres.
- Published
- 2008
- Full Text
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10. Homeologous recombination plays a major role in chromosome rearrangements that occur during meiosis of Brassica napus haploids.
- Author
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Nicolas SD, Le Mignon G, Eber F, Coriton O, Monod H, Clouet V, Huteau V, Lostanlen A, Delourme R, Chalhoub B, Ryder CD, Chèvre AM, and Jenczewski E
- Subjects
- Alleles, Chromosome Segregation, Crosses, Genetic, Gene Dosage, Genetic Markers, Genome, Plant genetics, In Situ Hybridization, Fluorescence, Metaphase, Polymerase Chain Reaction, Brassica napus cytology, Brassica napus genetics, Chromosomes, Plant genetics, Gene Rearrangement, Haploidy, Meiosis genetics, Recombination, Genetic genetics
- Abstract
Chromosomal rearrangements can be triggered by recombination between distinct but related regions. Brassica napus (AACC; 2n = 38) is a recent allopolyploid species whose progenitor genomes are widely replicated. In this article, we analyze the extent to which chromosomal rearrangements originate from homeologous recombination during meiosis of haploid B. napus (n = 19) by genotyping progenies of haploid x euploid B. napus with molecular markers. Our study focuses on three pairs of homeologous regions selected for their differing levels of divergence (N1/N11, N3/N13, and N9/N18). We show that a high number of chromosomal rearrangements occur during meiosis of B. napus haploid and are transmitted by first division restitution (FDR)-like unreduced gametes to their progeny; half of the progeny of Darmor-bzh haploids display duplications and/or losses in the chromosomal regions being studied. We demonstrate that half of these rearrangements are due to recombination between regions of primary homeology, which represents a 10- to 100-fold increase compared to the frequency of homeologous recombination measured in euploid lines. Some of the other rearrangements certainly result from recombination between paralogous regions because we observed an average of one to two autosyndetic A-A and/or C-C bivalents at metaphase I of the B. napus haploid. These results are discussed in the context of genome evolution of B. napus.
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- 2007
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11. Mapping PrBn and other quantitative trait loci responsible for the control of homeologous chromosome pairing in oilseed rape (Brassica napus L.) haploids.
- Author
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Liu Z, Adamczyk K, Manzanares-Dauleux M, Eber F, Lucas MO, Delourme R, Chèvre AM, and Jenczewski E
- Subjects
- Chromosomes, Plant, Genetic Markers, Nucleic Acid Amplification Techniques methods, Polymorphism, Genetic, Brassica napus genetics, Chromosome Pairing, Haploidy, Physical Chromosome Mapping, Quantitative Trait Loci
- Abstract
In allopolyploid species, fair meiosis could be challenged by homeologous chromosome pairing and is usually achieved by the action of homeologous pairing suppressor genes. Oilseed rape (Brassica napus) haploids (AC, n=19) represent an attractive model for studying the mechanisms used by allopolyploids to ensure the diploid-like meiotic pairing pattern. In oilseed rape haploids, homeologous chromosome pairing at metaphase I was found to be genetically based and controlled by a major gene, PrBn, segregating in a background of polygenic variation. In this study, we have mapped PrBn within a 10-cM interval on the C genome linkage group DY15 and shown that PrBn displays incomplete penetrance or variable expressivity. We have identified three to six minor QTL/BTL that have slight additive effects on the amount of pairing at metaphase I but do not interact with PrBn. We have also detected a number of other loci that interact epistatically, notably with PrBn. Our results support the idea that, as in other polyploid species, metaphase I homeologous pairing in oilseed rape haploids is controlled by an integrated system of several genes, which function in a complex manner.
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- 2006
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12. PrBn, a major gene controlling homeologous pairing in oilseed rape (Brassica napus) haploids.
- Author
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Jenczewski E, Eber F, Grimaud A, Huet S, Lucas MO, Monod H, and Chèvre AM
- Subjects
- Alleles, Crosses, Genetic, Genotype, Haploidy, Likelihood Functions, Meiosis, Metaphase, Models, Genetic, Models, Statistical, Ploidies, Brassica napus genetics, Genes, Plant genetics
- Abstract
Precise control of chromosome pairing is vital for conferring meiotic, and hence reproductive, stability in sexually reproducing polyploids. Apart from the Ph1 locus of wheat that suppresses homeologous pairing, little is known about the activity of genes that contribute to the cytological diploidization of allopolyploids. In oilseed rape (Brassica napus) haploids, the amount of chromosome pairing at metaphase I (MI) of meiosis varies depending on the varieties the haploids originate from. In this study, we combined a segregation analysis with a maximum-likelihood approach to demonstrate that this variation is genetically based and controlled mainly by a gene with a major effect. A total of 244 haploids were produced from F(1) hybrids between a high- and a low-pairing variety (at the haploid stage) and their meiotic behavior at MI was characterized. Likelihood-ratio statistics were used to demonstrate that the distribution of the number of univalents among these haploids was consistent with the segregation of a diallelic major gene, presumably in a background of polygenic variation. Our observations suggest that this gene, named PrBn, is different from Ph1 and could thus provide complementary information on the meiotic stabilization of chromosome pairing in allopolyploid species.
- Published
- 2003
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13. FANCM Limits Meiotic Crossovers in Brassica Crops
- Author
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Blary, Aurélien, Gonzalo, Adrián, Eber, Frederique, Berard, Aurélie, Berges, Helene, Bessoltane, Nadia, Charif, Delphine, Charpentier, Catherine, Cromer, Laurence, Fourment, Joelle, Genevriez, Camille, Le Paslier, Marie-Christine, Lodé-Taburel, Maryse, Lucas, Marie-Odile, Nesi, Nathalie, Lloyd, Andrew, Chèvre, Anne-Marie, Jenczewski, Eric, Institut Jean-Pierre Bourgin (IJPB), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Department of Ecology and Evolution, Université de Lausanne = University of Lausanne (UNIL), Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST, Etude du Polymorphisme des Génomes Végétaux (EPGV), Institut National de la Recherche Agronomique (INRA), Centre National de Ressources Génomiques Végétales (CNRGV), ANR-14-CE19-0004 - CROC, INRA BAP division (Appel a Manifestation d'interet, HyperRec), LabEx Saclay Plant Sciences-SPS [ANR-10-LABX-0040-SPS], PIOF-GA-2013-628128 POLYMEIO, ANR-14-CE19-0004,CROC,Contrôle de la fréquence de recombinaison méiotique pour accélérer l'innovation variétales chez les espèces cultivées polyploïdes(2014), ANR-11-IDEX-0002,UNITI,Université Fédérale de Toulouse(2011), European Project: 606956,EC:FP7:PEOPLE,FP7-PEOPLE-2013-ITN,COMREC(2013), Université de Lausanne (UNIL), Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, and Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)
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méiose ,Vegetal Biology ,FANCM ,brassica ,meiotic crossover ,TILLING ,plant breeding ,polyploidy ,Translational biology ,arabidopsis thaliana ,fungi ,Correction ,food and beverages ,Plant Science ,lcsh:Plant culture ,variation génétique ,brassica napus ,[SDV.BV]Life Sciences [q-bio]/Vegetal Biology ,lcsh:SB1-1110 ,mutation ,Biologie végétale ,Original Research ,sélection végétale - Abstract
International audience; Meiotic crossovers (COs) are essential for proper chromosome segregation and the reshuffling of alleles during meiosis. In WT plants, the number of COs is usually small, which limits the genetic variation that can be captured by plant breeding programs. Part of this limitation is imposed by proteins like FANCM, the inactivation of which results in a 3-fold increase in COs in Arabidopsis thaliana. Whether the same holds true in crops needed to be established. In this study, we identified EMS induced mutations in FANCM in two species of economic relevance within the genus Brassica. We showed that CO frequencies were increased in fancm mutants in both diploid and tetraploid Brassicas, Brassica rapa and Brassica napus respectively. In B. rapa, we observed a 3-fold increase in the number of COs, equal to the increase observed previously in Arabidopsis. In B. napus we observed a lesser but consistent increase (1.3-fold) in both euploid (AACC) and allohaploid (AC) plants. Complementation tests in A. thaliana suggest that the smaller increase in crossover frequency observed in B. napus reflects residual activity of the mutant C copy of FANCM. Altogether our results indicate that the anti-CO activity of FANCM is conserved across the Brassica, opening new avenues to make a wider range of genetic diversity accessible to crop improvement.
- Published
- 2018
14. Non-random distribution of extensive chromosome rearrangements in Brassica napus depends on genome organization
- Author
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Nicolas, Stephane, Monod, Herve, Eber, Frederique, Chèvre, Anne-Marie, Jenczewski, Eric, Institut de Génétique, Environnement et Protection des Plantes (IGEPP), AGROCAMPUS OUEST-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Recherche Agronomique (INRA), Unité de recherche Mathématiques et Informatique Appliquées (MIA), Institut National de la Recherche Agronomique (INRA), Institut Jean-Pierre Bourgin (IJPB), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Centre Technique Interprofessionnel des Oleagineux Metropolitains, Institut National de Recherche Agronomique - Genetique et Amelioration des Plantes, Agence Nationale de la Recherche [ANR-05-BDIV-015], Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST, and ANR-05-BDIV-0015,Polyploidie,Effet de la polyploïdie sur la biodiversité et l'évolution du génome des plantes (BioPPG)(2005)
- Subjects
[SDV.SA]Life Sciences [q-bio]/Agricultural sciences ,genome rearrangement ,polyploidy ,structural variation ,homeologous recombination ,genome evolution ,meiotic recombination ,WHEAT ,Haploidy ,Chromosomes, Plant ,Linkage Disequilibrium ,Evolution, Molecular ,évolution moléculaire ,distribution ,POLYPLOFORMATION ,chromosome ,Crosses, Genetic ,Phylogeny ,COPY NUMBER VARIATION ,Gene Rearrangement ,Models, Genetic ,Brassica napus ,Chromosome Mapping ,Genetic Variation ,HOMEOLOGOUS RECOMBINATION ,GENETIC-REGULATION ,Diploidy ,EVOLUTION ,RECOMBINATION RATES ,Meiosis ,COMPARATIVE MAPS ,Fertility ,Genetic Loci ,HAPLOIDS ,évolution du génome ,ARABIDOPSIS-THALIANA ,Genome, Plant - Abstract
International audience; Chromosome rearrangements are common, but their dynamics over time, mechanisms of occurrence and the genomic features that shape their distribution and rate are still poorly understood. We used allohaploid Brassica napus (AC, n = 19) as a model to analyze the effect of genomic features on the formation and diversity of meiotically driven chromosome rearrangements. We showed that allohaploid B. napus meiosis leads to extensive new structural diversity. Almost every allohaploid offspring carried a unique combination of multiple rearrangements throughout the genome, and was thus structurally differentiated from both its haploid parent and its sister plants. This large amount of genome reshuffling was remarkably well-tolerated in the heterozygous state, as neither male nor female fertility were strongly reduced, and meiosis behavior was normal in most cases. We also used a quantitative statistical model, which accounted for 75% of the observed variation in rearrangement rates, to show that the distribution of meiotically driven chromosome rearrangements was not random but was shaped by three principal genomic features. In descending order of importance, the rate of marker loss increased strongly with genetic distance from the centromere, the degree of collinearity between chromosomes, and the genome of origin (A < C). Overall, our results demonstrate that B. napus accumulates a large number of genetic changes, but these rearrangements are not randomly distributed in the genome. The structural genetic diversity produced by the allohaploid pathway and its role in the evolution of polyploid species compared to diploid meiosis are discussed.
- Published
- 2012
15. First meioses of Brassica napus are genome blenders
- Author
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Szadkowski, Emmanuel, Eber, Frederique, Huteau, Virginie, Coriton, Olivier, Jenczewski, Eric, Chèvre, Anne-Marie, Amélioration des Plantes et Biotechnologies Végétales (APBV), Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Institut Jean-Pierre Bourgin (IJPB), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, AGROCAMPUS OUEST-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Recherche Agronomique (INRA), and Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST
- Subjects
fungi ,polyploïdie ,food and beverages ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,expression du génome ,polyploidy ,brassica napus - Abstract
First meioses of Brassica napus are genome blenders. Plant and Animal Genomes Conference
- Published
- 2011
16. La première méiose des colzas resynthetisés, un mixeur de génome
- Author
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Szadkowski, Emmanuel, Eber, Frederique, Huteau, Virginie, Coriton, Olivier, Chalhoub, Boulos, Jenczewski, Eric, Chèvre, Anne-Marie, Amélioration des Plantes et Biotechnologies Végétales (APBV), AGROCAMPUS OUEST-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Recherche Agronomique (INRA), Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, Unité de recherche en génomique végétale (URGV), Centre National de la Recherche Scientifique (CNRS)-Université d'Évry-Val-d'Essonne (UEVE)-Institut National de la Recherche Agronomique (INRA), Centre National de la Recherche Scientifique (CNRS), Institut Jean-Pierre Bourgin (IJPB), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut National de la Recherche Agronomique (INRA)-Université d'Évry-Val-d'Essonne (UEVE)-Centre National de la Recherche Scientifique (CNRS), Institut National de Recherche Agronomique (INRA). UMR Amélioration des Plantes et Biotechnologies Végétales (0118)., and Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST
- Subjects
méiose ,synthetic hybrids ,synteny ,food and beverages ,meiosis ,[SDV.BV]Life Sciences [q-bio]/Vegetal Biology ,Brassica ,expression du génome ,recombination ,allopolyploid ,brassica napus - Abstract
Chromosomal reshuffling occurs during meiosis in newly created polyploid species in Brassica, contributing to differentiation of parental genomes in the hybrid. In newly synthesized Brassica napus, studies have shown little effect of the very first meiosis in genomic restructuring. However, the frequent and non random fixation of translocations (HNRTs) in early generations of re-synthesized B. napus suppose a major role of the first meiosis in chromosome rearrangements. To study homeologous pairing and remodelling at the creation of the polyploidy, homeologous pair of chromosomes A1-C1 provide an appropriate model, being completely collinear in macrosynteny in B. napus and its progenitors and being the most rearranged pair in natural B. napus haploids.On multiple lineages of synthetic B.napus, we aimed to : (i) Establish the frequent pairing of A1-C1 during the first meiosis of neo-polyploids; (ii) Assess precisely the impact of this meiosis on the nature, the size and the frequency of rearrangements generated on A1 and C1; (iii) Determine the effect of A1-C1 rearrangements on the perturbation of regular meiotic behaviour in contrasted progeny. (i) Various S0 (colchicines doubled hybrids) lineages of resynthesized B. napus have been created from 4 different diploid parents to test genetic background as long as a reciprocal cross to test maternal cytoplasmic effect. By using BAC-FISH (Fluorescent In Situ Hybridisation) approach at meiosis of the first generation S0, it is possible to detect implication of A1-C1 in abnormal chromosome pairing. Evidence for A-C pairing at first meiosis exist, and this work will determine the A1-C1 pairing ability of the progenitors structure. (ii) To assess the impact of first meiosis on genome remodelling in gametes, crosses were performed between the 4 amphidiploids (S0) and a natural B. napus (92 ind. for each). We identified a contrasted behaviour of the B. rapa cytoplasm population, but all had highly frequent inherited chromosomes rearrangements using molecular markers from A1 and C1, and their nature (translocation vs. deletion) will be discussed on a subset of contrasted individuals using BAC FISH differentiating homeologous regions. (iii) By establishing the meiotic behaviour of this subset of plants, we will validate the effect of A1-C1 homogenisation on further genome instability. These data will bring new insight on genome restructuration in polyploids after genome duplication.
- Published
- 2010
17. Polyploid formation ways in Brassica napus: The Tortoise and the Hare
- Author
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Szadkowski, Emmanuel, Eber, Frederique, Huteau, Virginie, Lode, Maryse, Coriton, Olivier, Jenczewski, Eric, Chèvre, Anne-Marie, Institut de Génétique, Environnement et Protection des Plantes (IGEPP), Institut National de la Recherche Agronomique (INRA)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Institut National de Recherche Agronomique (INRA). UMR Institut de Génétique Environnement et Protection des Plantes (1349)., Institut National de la Recherche Agronomique (INRA)-Université de Rennes (UR)-AGROCAMPUS OUEST, AGROCAMPUS OUEST-Université de Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National de la Recherche Agronomique (INRA)
- Subjects
[SDV]Life Sciences [q-bio] ,polyploïdie ,polyploidy ,brassica napus - Abstract
Polyploid formation ways in Brassica napus: The Tortoise and the Hare. Réunion du groupe « Cytogénétique et Polyploïdie »
- Published
- 2010
18. Gene Flow from Oilseed Rape to Weedy Species.
- Author
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Chèvre, Anne-marie, Eber, Frédérique, Jenczewski, Eric, Darmency, Henri, and Renard, Michel
- Subjects
TRANSGENES ,OILSEED plants ,WEEDS ,SPECIES hybridization - Abstract
The assessment of the likelihood of transgene spread from cultivated species to their wild relatives is relevant for oilseed rape ( Brassica napus , AACC, 2 n =38) as it is partially allogamous and presents numerous wild relatives growing nearby in cultivated areas and having an overlapping of the flowering period. We have assessed the probability of F1 interspecific hybrid formation between oilseed rape and three main weeds encountered in France, wild mustard ( Sinapis arvensis , SarSar, 2 n =18), hoary mustard ( Hirschfeldia incana , AdAd, 2 n =14) and wild radish ( Raphanus raphanistrum , RrRr, 2 n =18), under optimal conditions. Because of the higher frequency of interspecific hybrids observed with this latter weed, complementary field experiments were carried out under normal agronomic conditions. The F1 hybrids obtained showed different genomic structures, either 2 n =28, or 2 n =37, or 2 n =56. These different hybrids were cultivated in the presence of wild radish and the succeeding generations were studied. [ABSTRACT FROM AUTHOR]
- Published
- 2003
- Full Text
- View/download PDF
19. Reducing MSH4 copy number prevents meiotic crossovers between non-homologous chromosomes in Brassica napus
- Author
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Gonzalo, Adrian, Lucas, Marie-Odile, Charpentier, Catherine, Sandmann, Greta, Lloyd, Andrew, and Jenczewski, Eric
- Subjects
recombinaison méiotique ,food and beverages ,brassica napus ,expression des gènes - Abstract
In allopolyploids, correct chromosome segregation requires suppression of non-homologous crossovers while levels of homologous crossovers are ensured. To date, no mechanism able to specifically inhibit non-homologous crossovers has been described in allopolyploids other than in bread wheat. Here, we show that reducing the number of functional copies of MSH4, an essential gene for the main crossover pathway, prevents non-homologous crossovers in allotetraploid Brassica napus. We show that non-homologous crossovers originate almost exclusively from the MSH4-dependent recombination pathway and that their numbers decrease when MSH4 returns to single copy in B. napus; by contrast, homologous crossovers remain unaffected by MSH4 duplicate loss. We also demonstrate that MSH4 systematically returns to single copy following numerous independent polyploidy events, a pattern that is probably not by chance. These results suggest that stabilization of allopolyploid meiosis can be enhanced by loss of a key meiotic recombination gene.
- Published
- 2019
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