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Bird KA, Pires JC, VanBuren R, Xiong Z, Edger PP. Dosage-sensitivity shapes how genes transcriptionally respond to allopolyploidy and homoeologous exchange in resynthesized Brassica napus. Genetics 2023; 225:iyad114. [PMID: 37338008 PMCID: PMC10471226 DOI: 10.1093/genetics/iyad114] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Revised: 03/10/2023] [Accepted: 06/12/2023] [Indexed: 06/21/2023] Open
Abstract
The gene balance hypothesis proposes that selection acts on the dosage (i.e. copy number) of genes within dosage-sensitive portions of networks, pathways, and protein complexes to maintain balanced stoichiometry of interacting proteins, because perturbations to stoichiometric balance can result in reduced fitness. This selection has been called dosage balance selection. Dosage balance selection is also hypothesized to constrain expression responses to dosage changes, making dosage-sensitive genes (those encoding members of interacting proteins) experience more similar expression changes. In allopolyploids, where whole-genome duplication involves hybridization of diverged lineages, organisms often experience homoeologous exchanges that recombine, duplicate, and delete homoeologous regions of the genome and alter the expression of homoeologous gene pairs. Although the gene balance hypothesis makes predictions about the expression response to homoeologous exchanges, they have not been empirically tested. We used genomic and transcriptomic data from 6 resynthesized, isogenic Brassica napus lines over 10 generations to identify homoeologous exchanges, analyzed expression responses, and tested for patterns of genomic imbalance. Groups of dosage-sensitive genes had less variable expression responses to homoeologous exchanges than dosage-insensitive genes, a sign that their relative dosage is constrained. This difference was absent for homoeologous pairs whose expression was biased toward the B. napus A subgenome. Finally, the expression response to homoeologous exchanges was more variable than the response to whole-genome duplication, suggesting homoeologous exchanges create genomic imbalance. These findings expand our knowledge of the impact of dosage balance selection on genome evolution and potentially connect patterns in polyploid genomes over time, from homoeolog expression bias to duplicate gene retention.
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Affiliation(s)
- Kevin A Bird
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
| | - J Chris Pires
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO 80523, USA
| | - Robert VanBuren
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
- Plant Resilience Institute, Michigan State University, East Lansing, MI 48824, USA
| | - Zhiyong Xiong
- Key Laboratory of Herbage and Endemic Crop Biotechnology, Inner Mongolia University, Hohhot, Inner Mongolia 010070, China
| | - Patrick P Edger
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
- Ecology, Evolution, and Behavior Program, Michigan State University, East Lansing, MI 48824, USA
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2
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Katche EI, Schierholt A, Schiessl SV, He F, Lv Z, Batley J, Becker HC, Mason AS. Genetic factors inherited from both diploid parents interact to affect genome stability and fertility in resynthesized allotetraploid Brassica napus. G3 (BETHESDA, MD.) 2023; 13:jkad136. [PMID: 37313757 PMCID: PMC10411605 DOI: 10.1093/g3journal/jkad136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 04/24/2023] [Accepted: 05/31/2023] [Indexed: 06/15/2023]
Abstract
Established allopolyploids are known to be genomically stable and fertile. However, in contrast, most newly resynthesized allopolyploids are infertile and meiotically unstable. Identifying the genetic factors responsible for genome stability in newly formed allopolyploid is key to understanding how 2 genomes come together to form a species. One hypothesis is that established allopolyploids may have inherited specific alleles from their diploid progenitors which conferred meiotic stability. Resynthesized Brassica napus lines are often unstable and infertile, unlike B. napus cultivars. We tested this hypothesis by characterizing 41 resynthesized B. napus lines produced by crosses between 8 Brassica rapa and 8 Brassica oleracea lines for copy number variation resulting from nonhomologous recombination events and fertility. We resequenced 8 B. rapa and 5 B. oleracea parent accessions and analyzed 19 resynthesized lines for allelic variation in a list of meiosis gene homologs. SNP genotyping was performed using the Illumina Infinium Brassica 60K array for 3 individuals per line. Self-pollinated seed set and genome stability (number of copy number variants) were significantly affected by the interaction between both B. rapa and B. oleracea parental genotypes. We identified 13 putative meiosis gene candidates which were significantly associated with frequency of copy number variants and which contained putatively harmful mutations in meiosis gene haplotypes for further investigation. Our results support the hypothesis that allelic variants inherited from parental genotypes affect genome stability and fertility in resynthesized rapeseed.
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Affiliation(s)
- Elizabeth Ihien Katche
- Plant Breeding Department, University of Bonn, Bonn 53115, Germany
- Department of Plant Breeding, Justus Liebig University, Giessen 35392, Germany
| | - Antje Schierholt
- Department of Crop Sciences, Division of Plant Breeding Methodology, Georg-August University Göttingen, Göttingen 37073, Germany
| | - Sarah-Veronica Schiessl
- Department of Plant Breeding, Justus Liebig University, Giessen 35392, Germany
- Department of Botany and Molecular Evolution, Senckenberg Research Institute and Natural History Museum Frankfurt, Frankfurt am Main D-60325, Germany
| | - Fei He
- Plant Breeding Department, University of Bonn, Bonn 53115, Germany
| | - Zhenling Lv
- Plant Breeding Department, University of Bonn, Bonn 53115, Germany
- Department of Plant Breeding, Justus Liebig University, Giessen 35392, Germany
| | - Jacqueline Batley
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia
| | - Heiko C Becker
- Department of Crop Sciences, Division of Plant Breeding Methodology, Georg-August University Göttingen, Göttingen 37073, Germany
| | - Annaliese S Mason
- Plant Breeding Department, University of Bonn, Bonn 53115, Germany
- Department of Plant Breeding, Justus Liebig University, Giessen 35392, Germany
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3
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Deb SK, Edger PP, Pires JC, McKain MR. Patterns, mechanisms, and consequences of homoeologous exchange in allopolyploid angiosperms: a genomic and epigenomic perspective. THE NEW PHYTOLOGIST 2023; 238:2284-2304. [PMID: 37010081 DOI: 10.1111/nph.18927] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 03/16/2023] [Indexed: 05/19/2023]
Abstract
Allopolyploids result from hybridization between different evolutionary lineages coupled with genome doubling. Homoeologous chromosomes (chromosomes with common shared ancestry) may undergo recombination immediately after allopolyploid formation and continue over successive generations. The outcome of this meiotic pairing behavior is dynamic and complex. Homoeologous exchanges (HEs) may lead to the formation of unbalanced gametes, reduced fertility, and selective disadvantage. By contrast, HEs could act as sources of novel evolutionary substrates, shifting the relative dosage of parental gene copies, generating novel phenotypic diversity, and helping the establishment of neo-allopolyploids. However, HE patterns vary among lineages, across generations, and even within individual genomes and chromosomes. The causes and consequences of this variation are not fully understood, though interest in this evolutionary phenomenon has increased in the last decade. Recent technological advances show promise in uncovering the mechanistic basis of HEs. Here, we describe recent observations of the common patterns among allopolyploid angiosperm lineages, underlying genomic and epigenomic features, and consequences of HEs. We identify critical research gaps and discuss future directions with far-reaching implications in understanding allopolyploid evolution and applying them to the development of important phenotypic traits of polyploid crops.
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Affiliation(s)
- Sontosh K Deb
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, 35487, USA
- Department of Forestry and Environmental Science, Shahjalal University of Science and Technology, Sylhet, 3114, Bangladesh
| | - Patrick P Edger
- Department of Horticulture, Michigan State University, East Lansing, MI, 48823, USA
- Genetics and Genome Sciences Program, Michigan State University, East Lansing, MI, 48823, USA
| | - J Chris Pires
- Department of Soil and Crop Sciences, Colorado State University, Fort Collins, CO, 80523, USA
| | - Michael R McKain
- Department of Biological Sciences, The University of Alabama, Tuscaloosa, AL, 35487, USA
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4
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Yim WC, Swain ML, Ma D, An H, Bird KA, Curdie DD, Wang S, Ham HD, Luzuriaga-Neira A, Kirkwood JS, Hur M, Solomon JKQ, Harper JF, Kosma DK, Alvarez-Ponce D, Cushman JC, Edger PP, Mason AS, Pires JC, Tang H, Zhang X. The final piece of the Triangle of U: Evolution of the tetraploid Brassica carinata genome. THE PLANT CELL 2022; 34:4143-4172. [PMID: 35961044 PMCID: PMC9614464 DOI: 10.1093/plcell/koac249] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Accepted: 06/24/2022] [Indexed: 05/05/2023]
Abstract
Ethiopian mustard (Brassica carinata) is an ancient crop with remarkable stress resilience and a desirable seed fatty acid profile for biofuel uses. Brassica carinata is one of six Brassica species that share three major genomes from three diploid species (AA, BB, and CC) that spontaneously hybridized in a pairwise manner to form three allotetraploid species (AABB, AACC, and BBCC). Of the genomes of these species, that of B. carinata is the least understood. Here, we report a chromosome scale 1.31-Gbp genome assembly with 156.9-fold sequencing coverage for B. carinata, completing the reference genomes comprising the classic Triangle of U, a classical theory of the evolutionary relationships among these six species. Our assembly provides insights into the hybridization event that led to the current B. carinata genome and the genomic features that gave rise to the superior agronomic traits of B. carinata. Notably, we identified an expansion of transcription factor networks and agronomically important gene families. Completion of the Triangle of U comparative genomics platform has allowed us to examine the dynamics of polyploid evolution and the role of subgenome dominance in the domestication and continuing agronomic improvement of B. carinata and other Brassica species.
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Affiliation(s)
| | | | - Dongna Ma
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Hong An
- Division of Biological Sciences, University of Missouri, Columbia, Missouri 65201, USA
| | - Kevin A Bird
- Department of Horticulture, Michigan State University, East Lansing, Michigan 48824, USA
| | - David D Curdie
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Samuel Wang
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Hyun Don Ham
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | | | - Jay S Kirkwood
- Metabolomics Core Facility, Institute for Integrative Genome Biology, University of California, Riverside, California 92521, USA
| | - Manhoi Hur
- Metabolomics Core Facility, Institute for Integrative Genome Biology, University of California, Riverside, California 92521, USA
| | - Juan K Q Solomon
- Department of Agriculture, Veterinary & Rangeland Sciences, University of Nevada, Reno, Nevada 89557, USA
| | - Jeffrey F Harper
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Dylan K Kosma
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | | | - John C Cushman
- Department of Biochemistry and Molecular Biology, University of Nevada, Reno, Nevada 89557, USA
| | - Patrick P Edger
- Department of Horticulture, Michigan State University, East Lansing, Michigan 48824, USA
| | - Annaliese S Mason
- Plant Breeding Department, INRES, The University of Bonn, Bonn 53115, Germany
| | - J Chris Pires
- Division of Biological Sciences, Bond Life Sciences Center, , University of Missouri, Columbia, Missouri 65211, USA
| | - Haibao Tang
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xingtan Zhang
- Fujian Provincial Key Laboratory of Haixia Applied Plant Systems Biology, Key Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of Crops, Key Laboratory of National Forestry and Grassland Administration for Orchid Conservation and Utilization, Fujian Agriculture and Forestry University, Fuzhou, China
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5
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Zhao Q, Meng Y, Wang P, Qin X, Cheng C, Zhou J, Yu X, Li J, Lou Q, Jahn M, Chen J. Reconstruction of ancestral karyotype illuminates chromosome evolution in the genus Cucumis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1243-1259. [PMID: 34160852 DOI: 10.1111/tpj.15381] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 06/06/2021] [Accepted: 06/19/2021] [Indexed: 05/22/2023]
Abstract
Karyotype dynamics driven by complex chromosome rearrangements constitute a fundamental issue in evolutionary genetics. The evolutionary events underlying karyotype diversity within plant genera, however, have rarely been reconstructed from a computed ancestral progenitor. Here, we developed a method to rapidly and accurately represent extant karyotypes with the genus, Cucumis, using highly customizable comparative oligo-painting (COP) allowing visualization of fine-scale genome structures of eight Cucumis species from both African-origin and Asian-origin clades. Based on COP data, an evolutionary framework containing a genus-level ancestral karyotype was reconstructed, allowing elucidation of the evolutionary events that account for the origin of these diverse genomes within Cucumis. Our results characterize the cryptic rearrangement hotspots on ancestral chromosomes, and demonstrate that the ancestral Cucumis karyotype (n = 12) evolved to extant Cucumis genomes by hybridizations and frequent lineage- and species-specific genome reshuffling. Relative to the African species, the Asian species, including melon (Cucumis melo, n = 12), Cucumis hystrix (n = 12) and cucumber (Cucumis sativus, n = 7), had highly shuffled genomes caused by large-scale inversions, centromere repositioning and chromothripsis-like rearrangement. The deduced reconstructed ancestral karyotype for the genus allowed us to propose evolutionary trajectories and specific events underlying the origin of these Cucumis species. Our findings highlight that the partitioned evolutionary plasticity of Cucumis karyotype is primarily located in the centromere-proximal regions marked by rearrangement hotspots, which can potentially serve as a reservoir for chromosome evolution due to their fragility.
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Affiliation(s)
- Qinzheng Zhao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ya Meng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Panqiao Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiaodong Qin
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Chunyan Cheng
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Junguo Zhou
- College of Horticulture and landscape, Henan Institute of Science and Technology, Xinxiang, 453000, China
| | - Xiaqing Yu
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Ji Li
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Qunfeng Lou
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
| | - Molly Jahn
- Department of Agronomy, University of Wisconsin-Madison, Madison, WI, 53726, USA
| | - Jinfeng Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Horticulture, Nanjing Agricultural University, Nanjing, 210095, China
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6
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Ferreira de Carvalho J, Stoeckel S, Eber F, Lodé-Taburel M, Gilet MM, Trotoux G, Morice J, Falentin C, Chèvre AM, Rousseau-Gueutin M. Untangling structural factors driving genome stabilization in nascent Brassica napus allopolyploids. THE NEW PHYTOLOGIST 2021; 230:2072-2084. [PMID: 33638877 DOI: 10.1111/nph.17308] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 02/22/2021] [Indexed: 05/28/2023]
Abstract
Allopolyploids have globally higher fitness than their diploid progenitors; however, by comparison, most resynthesized allopolyploids have poor fertility and highly unstable genome. Elucidating the evolutionary processes promoting genome stabilization and fertility is thus essential to comprehend allopolyploid success. Using the Brassica model, we mimicked the speciation process of a nascent allopolyploid species by resynthesizing allotetraploid Brassica napus and systematically selecting for euploid individuals over eight generations in four independent allopolyploidization events with contrasted genetic backgrounds, cytoplasmic donors, and polyploid formation type. We evaluated the evolution of meiotic behavior and fertility and identified rearrangements in S1 to S9 lineages to explore the positive consequences of euploid selection on B. napus genome stability. Recurrent selection of euploid plants for eight generations drastically reduced the percentage of aneuploid progenies as early as the fourth generation, concomitantly with a decrease in number of newly fixed homoeologous rearrangements. The consequences of homoeologous rearrangements on meiotic behavior and seed number depended strongly on the genetic background and cytoplasm donor. The combined use of both self-fertilization and recurrent euploid selection allowed identification of genomic regions associated with fertility and meiotic behavior, providing complementary evidence to explain B. napus speciation success.
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Affiliation(s)
| | - Solenn Stoeckel
- IGEPP, INRAE, Institut Agro, Université de Rennes, Le Rheu, 35650, France
| | - Frédérique Eber
- IGEPP, INRAE, Institut Agro, Université de Rennes, Le Rheu, 35650, France
| | | | | | - Gwenn Trotoux
- IGEPP, INRAE, Institut Agro, Université de Rennes, Le Rheu, 35650, France
| | - Jérôme Morice
- IGEPP, INRAE, Institut Agro, Université de Rennes, Le Rheu, 35650, France
| | - Cyril Falentin
- IGEPP, INRAE, Institut Agro, Université de Rennes, Le Rheu, 35650, France
| | - Anne-Marie Chèvre
- IGEPP, INRAE, Institut Agro, Université de Rennes, Le Rheu, 35650, France
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7
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Xiong Z, Gaeta RT, Edger PP, Cao Y, Zhao K, Zhang S, Pires JC. Chromosome inheritance and meiotic stability in allopolyploid Brassica napus. G3-GENES GENOMES GENETICS 2021; 11:6044140. [PMID: 33704431 PMCID: PMC8022990 DOI: 10.1093/g3journal/jkaa011] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 11/05/2020] [Indexed: 12/23/2022]
Abstract
Homoeologous recombination, aneuploidy, and other genetic changes are common in resynthesized allopolyploid Brassica napus. In contrast, the chromosomes of cultivars have long been considered to be meiotically stable. To gain a better understanding of the underlying mechanisms leading to stabilization in the allopolyploid, the behavior of chromosomes during meiosis can be compared by unambiguous chromosome identification between resynthesized and natural B. napus. Compared with natural B. napus, resynthesized lines show high rates of nonhomologous centromere association, homoeologous recombination leading to translocation, homoeologous chromosome replacement, and association and breakage of 45S rDNA loci. In both natural and resynthesized B. napus, we observed low rates of univalents, A–C bivalents, and early sister chromatid separations. Reciprocal homoeologous chromosome exchanges and double reductions were photographed for the first time in meiotic telophase I. Meiotic errors were non-uniformly distributed across the genome in resynthesized B. napus, and in particular homoeologs sharing synteny along their entire length exhibited multivalents at diakinesis and polysomic inheritance at telophase I. Natural B. napus appeared to resolve meiotic errors mainly by suppressing homoeologous pairing, resolving nonhomologous centromere associations and 45S rDNA associations before diakinesis, and reducing homoeologous cross-overs.
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Affiliation(s)
- Zhiyong Xiong
- Key Laboratory of Herbage and Endemic Crop Biotechnology, Ministry of Education, College of Life Science, Inner Mongolia University, Hohhot, Inner Mongolia 010021, PR China.,Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Robert T Gaeta
- Bayer's Crop Science Division, Chesterfield, MO 63017, USA
| | - Patrick P Edger
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA.,Department of Horticulture, Michigan State University, East Lansing, MI 48823, USA
| | - Yao Cao
- Key Laboratory of Herbage and Endemic Crop Biotechnology, Ministry of Education, College of Life Science, Inner Mongolia University, Hohhot, Inner Mongolia 010021, PR China
| | - Kanglu Zhao
- Key Laboratory of Herbage and Endemic Crop Biotechnology, Ministry of Education, College of Life Science, Inner Mongolia University, Hohhot, Inner Mongolia 010021, PR China
| | - Siqi Zhang
- Key Laboratory of Herbage and Endemic Crop Biotechnology, Ministry of Education, College of Life Science, Inner Mongolia University, Hohhot, Inner Mongolia 010021, PR China
| | - J Chris Pires
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA
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8
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Mason AS, Wendel JF. Homoeologous Exchanges, Segmental Allopolyploidy, and Polyploid Genome Evolution. Front Genet 2020; 11:1014. [PMID: 33005183 PMCID: PMC7485112 DOI: 10.3389/fgene.2020.01014] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 08/10/2020] [Indexed: 01/08/2023] Open
Abstract
Polyploidy is a major force in plant evolution and speciation. In newly formed allopolyploids, pairing between related chromosomes from different subgenomes (homoeologous chromosomes) during meiosis is common. The initial stages of allopolyploid formation are characterized by a spectrum of saltational genomic and regulatory alterations that are responsible for evolutionary novelty. Here we highlight the possible effects and roles of recombination between homoeologous chromosomes during the early stages of allopolyploid stabilization. Homoeologous exchanges (HEs) have been reported in young allopolyploids from across the angiosperms. Although all lineages undergo karyotype change via chromosome rearrangements over time, the early generations after allopolyploid formation are predicted to show an accelerated rate of genomic change. HEs can also cause changes in allele dosage, genome-wide methylation patterns, and downstream phenotypes, and can hence be responsible for speciation and genome stabilization events. Additionally, we propose that fixation of duplication - deletion events resulting from HEs could lead to the production of genomes which appear to be a mix of autopolyploid and allopolyploid segments, sometimes termed "segmental allopolyploids." We discuss the implications of these findings for our understanding of the relationship between genome instability in novel polyploids and genome evolution.
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Affiliation(s)
- Annaliese S. Mason
- Plant Breeding Department, Justus Liebig University Giessen, Giessen, Germany
| | - Jonathan F. Wendel
- Ecology, Evolution, and Organismal Biology Department, Iowa State University, Ames, IA, United States
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9
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Mwathi MW, Schiessl SV, Batley J, Mason AS. "Doubled-haploid" allohexaploid Brassica lines lose fertility and viability and accumulate genetic variation due to genomic instability. Chromosoma 2019; 128:521-532. [PMID: 31377850 DOI: 10.1007/s00412-019-00720-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Revised: 07/17/2019] [Accepted: 07/24/2019] [Indexed: 01/01/2023]
Abstract
Microspore culture stimulates immature pollen grains to develop into plants via tissue culture and is used routinely in many crop species to produce "doubled haploids": homozygous, true-breeding lines. However, microspore culture is also often used on material that does not have stable meiosis, such as interspecific hybrids. In this case, the resulting progeny may lose their "doubled haploid" homozygous status as a result of chromosome missegregation and homoeologous exchanges. However, little is known about the frequency of these effects. We assessed fertility, meiosis and genetic variability in self-pollinated progeny sets (the MDL2 population) resulting from first-generation plants (the MDL1 population) derived from microspores of a near-allohexaploid interspecific hybrid from the cross (Brassica napus × B. carinata) × B. juncea. Allelic inheritance and copy number variation were predicted using single nucleotide polymorphism marker data from the Illumina Infinium 60K Brassica array. Seed fertility and viability decreased substantially from the MDL1 to the MDL2 generation. In the MDL2 population, 87% of individuals differed genetically from their MDL1 parent. These genetic differences resulted from novel homoeologous exchanges between chromosomes, chromosome loss and gain, and segregation and instability of pre-existing karyotype abnormalities. Novel karyotype change was extremely common, with 2.2 new variants observed per MDL2 individual. Significant differences between progeny sets in the number of novel genetic variants were also observed. Meiotic instability clearly has the potential to dramatically change karyotypes (often without detectable effects on the presence or absence of alleles) in putatively homozygous, microspore-derived lines, resulting in loss of fertility and viability.
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Affiliation(s)
- Margaret W Mwathi
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.,School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia
| | - Sarah V Schiessl
- Department of Plant Breeding, Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany
| | - Jacqueline Batley
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.,School of Biological Sciences, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia
| | - Annaliese S Mason
- Department of Plant Breeding, Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
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10
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Diversity and Determinants of Meiotic Recombination Landscapes. Trends Genet 2019; 35:359-370. [DOI: 10.1016/j.tig.2019.02.002] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/06/2019] [Accepted: 02/08/2019] [Indexed: 11/19/2022]
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11
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Detecting de Novo Homoeologous Recombination Events in Cultivated Brassica napus Using a Genome-Wide SNP Array. G3-GENES GENOMES GENETICS 2018; 8:2673-2683. [PMID: 29907649 PMCID: PMC6071606 DOI: 10.1534/g3.118.200118] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The heavy selection pressure due to intensive breeding of Brassica napus has created a narrow gene pool, limiting the ability to produce improved varieties through crosses between B. napus cultivars. One mechanism that has contributed to the adaptation of important agronomic traits in the allotetraploid B. napus has been chromosomal rearrangements resulting from homoeologous recombination between the constituent A and C diploid genomes. Determining the rate and distribution of such events in natural B. napus will assist efforts to understand and potentially manipulate this phenomenon. The Brassica high-density 60K SNP array, which provides genome-wide coverage for assessment of recombination events, was used to assay 254 individuals derived from 11 diverse cultivated spring type B. napus. These analyses identified reciprocal allele gain and loss between the A and C genomes and allowed visualization of de novo homoeologous recombination events across the B. napus genome. The events ranged from loss/gain of 0.09 Mb to entire chromosomes, with almost 5% aneuploidy observed across all gametes. There was a bias toward sub-telomeric exchanges leading to genome homogenization at chromosome termini. The A genome replaced the C genome in 66% of events, and also featured more dominantly in gain of whole chromosomes. These analyses indicate de novo homoeologous recombination is a continuous source of variation in established Brassica napus and the rate of observed events appears to vary with genetic background. The Brassica 60K SNP array will be a useful tool in further study and manipulation of this phenomenon.
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12
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Hurgobin B, Golicz AA, Bayer PE, Chan CK, Tirnaz S, Dolatabadian A, Schiessl SV, Samans B, Montenegro JD, Parkin IAP, Pires JC, Chalhoub B, King GJ, Snowdon R, Batley J, Edwards D. Homoeologous exchange is a major cause of gene presence/absence variation in the amphidiploid Brassica napus. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:1265-1274. [PMID: 29205771 PMCID: PMC5999312 DOI: 10.1111/pbi.12867] [Citation(s) in RCA: 144] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 10/17/2017] [Accepted: 10/19/2017] [Indexed: 05/08/2023]
Abstract
Homoeologous exchanges (HEs) have been shown to generate novel gene combinations and phenotypes in a range of polyploid species. Gene presence/absence variation (PAV) is also a major contributor to genetic diversity. In this study, we show that there is an association between these two events, particularly in recent Brassica napus synthetic accessions, and that these represent a novel source of genetic diversity, which can be captured for the improvement of this important crop species. By assembling the pangenome of B. napus, we show that 38% of the genes display PAV behaviour, with some of these variable genes predicted to be involved in important agronomic traits including flowering time, disease resistance, acyl lipid metabolism and glucosinolate metabolism. This study is a first and provides a detailed characterization of the association between HEs and PAVs in B. napus at the pangenome level.
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Affiliation(s)
- Bhavna Hurgobin
- School of Biological Sciences and Institute of AgricultureThe University of Western AustraliaCrawleyWAAustralia
- School of Agriculture and Food SciencesUniversity of QueenslandSt. LuciaQLDAustralia
| | - Agnieszka A. Golicz
- Plant Molecular Biology and Biotechnology LaboratoryFaculty of Veterinary and Agricultural SciencesUniversity of MelbourneMelbourneVICAustralia
| | - Philipp E. Bayer
- School of Biological Sciences and Institute of AgricultureThe University of Western AustraliaCrawleyWAAustralia
| | - Chon‐Kit Kenneth Chan
- School of Biological Sciences and Institute of AgricultureThe University of Western AustraliaCrawleyWAAustralia
| | - Soodeh Tirnaz
- School of Biological Sciences and Institute of AgricultureThe University of Western AustraliaCrawleyWAAustralia
| | - Aria Dolatabadian
- School of Biological Sciences and Institute of AgricultureThe University of Western AustraliaCrawleyWAAustralia
| | - Sarah V. Schiessl
- Department of Plant BreedingIFZ Research Centre for Biosystems, Land Use and NutritionJustus Liebig UniversityGiessenGermany
| | - Birgit Samans
- Department of Plant BreedingIFZ Research Centre for Biosystems, Land Use and NutritionJustus Liebig UniversityGiessenGermany
| | - Juan D. Montenegro
- School of Agriculture and Food SciencesUniversity of QueenslandSt. LuciaQLDAustralia
| | | | - J. Chris Pires
- Division of Biological SciencesUniversity of MissouriColumbiaMOUSA
| | - Boulos Chalhoub
- Institute of System and Synthetic Biology, Organization and Evolution of Complex GenomesInstitut National de la Recherche agronomique, GenopoleCentre National de la Recherche ScientifiqueUniversité d'Evry Val d'EssonneUniversité Paris‐SaclayEvryFrance
| | - Graham J. King
- Southern Cross Plant ScienceSouthern Cross UniversityLismoreNSWAustralia
| | - Rod Snowdon
- Department of Plant BreedingIFZ Research Centre for Biosystems, Land Use and NutritionJustus Liebig UniversityGiessenGermany
| | - Jacqueline Batley
- School of Biological Sciences and Institute of AgricultureThe University of Western AustraliaCrawleyWAAustralia
| | - David Edwards
- School of Biological Sciences and Institute of AgricultureThe University of Western AustraliaCrawleyWAAustralia
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13
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Zou J, Hu D, Mason AS, Shen X, Wang X, Wang N, Grandke F, Wang M, Chang S, Snowdon RJ, Meng J. Genetic changes in a novel breeding population of Brassica napus synthesized from hundreds of crosses between B. rapa and B. carinata. PLANT BIOTECHNOLOGY JOURNAL 2018; 16:507-519. [PMID: 28703467 PMCID: PMC5811809 DOI: 10.1111/pbi.12791] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2017] [Revised: 06/29/2017] [Accepted: 07/07/2017] [Indexed: 05/20/2023]
Abstract
Introgression of genomic variation between and within related crop species is a significant evolutionary approach for population differentiation, genome reorganization and trait improvement. Using the Illumina Infinium Brassica 60K SNP array, we investigated genomic changes in a panel of advanced generation new-type Brassica napus breeding lines developed from hundreds of interspecific crosses between 122 Brassica rapa and 74 Brassica carinata accessions, and compared them with representative accessions of their three parental species. The new-type B. napus population presented rich genetic diversity and abundant novel genomic alterations, consisting of introgressions from B. rapa and B. carinata, novel allelic combinations, reconstructed linkage disequilibrium patterns and haplotype blocks, and frequent deletions and duplications (nonrandomly distributed), particularly in the C subgenome. After a much shorter, but very intensive, selection history compared to traditional B. napus, a total of 15 genomic regions with strong selective sweeps and 112 genomic regions with putative signals of selective sweeps were identified. Some of these regions were associated with important agronomic traits that were selected for during the breeding process, while others were potentially associated with restoration of genome stability and fertility after interspecific hybridization. Our results demonstrate how a novel method for population-based crop genetic improvement can lead to rapid adaptation, restoration of genome stability and positive responses to artificial selection.
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Affiliation(s)
- Jun Zou
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanChina
| | - Dandan Hu
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanChina
| | - Annaliese S. Mason
- Department of Plant BreedingIFZ Research Centre for BiosystemsLand Use and NutritionJustus Liebig UniversityGiessenGermany
| | - Xueqi Shen
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanChina
| | - Xiaohua Wang
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanChina
| | - Nian Wang
- College of Horticulture & Forestry SciencesHuazhong Agricultural UniversityWuhanChina
| | - Fabian Grandke
- Department of Plant BreedingIFZ Research Centre for BiosystemsLand Use and NutritionJustus Liebig UniversityGiessenGermany
| | - Meng Wang
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanChina
| | - Shihao Chang
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanChina
| | - Rod J. Snowdon
- Department of Plant BreedingIFZ Research Centre for BiosystemsLand Use and NutritionJustus Liebig UniversityGiessenGermany
| | - Jinling Meng
- National Key Laboratory of Crop Genetic ImprovementHuazhong Agricultural UniversityWuhanChina
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Lloyd A, Blary A, Charif D, Charpentier C, Tran J, Balzergue S, Delannoy E, Rigaill G, Jenczewski E. Homoeologous exchanges cause extensive dosage-dependent gene expression changes in an allopolyploid crop. THE NEW PHYTOLOGIST 2018; 217:367-377. [PMID: 29034956 DOI: 10.1111/nph.14836] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/01/2017] [Accepted: 08/02/2017] [Indexed: 05/22/2023]
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.
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Affiliation(s)
- Andrew Lloyd
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles Cedex, 78000, France
| | - Aurélien Blary
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles Cedex, 78000, France
| | - Delphine Charif
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles Cedex, 78000, France
| | - Catherine Charpentier
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles Cedex, 78000, France
| | - Joseph Tran
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles Cedex, 78000, France
- Institute of Plant Sciences Paris Saclay IPS2, CNRS, INRA, Université Paris-Sud, Université Evry, Université Paris-Saclay, Bâtiment 630, Orsay, 91405, France
- Institute of Plant Sciences Paris-Saclay IPS2, Paris Diderot, Sorbonne Paris-Cité, Bâtiment 630, Orsay, 91405, France
| | - Sandrine Balzergue
- Institute of Plant Sciences Paris Saclay IPS2, CNRS, INRA, Université Paris-Sud, Université Evry, Université Paris-Saclay, Bâtiment 630, Orsay, 91405, France
- Institute of Plant Sciences Paris-Saclay IPS2, Paris Diderot, Sorbonne Paris-Cité, Bâtiment 630, Orsay, 91405, France
- IRHS, INRA, AGROCAMPUS-Ouest, Université d'Angers, SFR 4207 QUASAV, 42 rue Georges Morel, Beaucouzé cedex, 49071, France
| | - Etienne Delannoy
- Institute of Plant Sciences Paris Saclay IPS2, CNRS, INRA, Université Paris-Sud, Université Evry, Université Paris-Saclay, Bâtiment 630, Orsay, 91405, France
- Institute of Plant Sciences Paris-Saclay IPS2, Paris Diderot, Sorbonne Paris-Cité, Bâtiment 630, Orsay, 91405, France
| | - Guillem Rigaill
- Institute of Plant Sciences Paris Saclay IPS2, CNRS, INRA, Université Paris-Sud, Université Evry, Université Paris-Saclay, Bâtiment 630, Orsay, 91405, France
- Institute of Plant Sciences Paris-Saclay IPS2, Paris Diderot, Sorbonne Paris-Cité, Bâtiment 630, Orsay, 91405, France
- Laboratoire de Mathématiques et Modélisation d'Evry (LaMME), Université d'Evry Val d'Essonne, UMR CNRS 8071, ENSIIE, USC INRA, Évry Cedex, France
| | - Eric Jenczewski
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles Cedex, 78000, France
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15
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Sun F, Fan G, Hu Q, Zhou Y, Guan M, Tong C, Li J, Du D, Qi C, Jiang L, Liu W, Huang S, Chen W, Yu J, Mei D, Meng J, Zeng P, Shi J, Liu K, Wang X, Wang X, Long Y, Liang X, Hu Z, Huang G, Dong C, Zhang H, Li J, Zhang Y, Li L, Shi C, Wang J, Lee SMY, Guan C, Xu X, Liu S, Liu X, Chalhoub B, Hua W, Wang H. The high-quality genome of Brassica napus cultivar 'ZS11' reveals the introgression history in semi-winter morphotype. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 92:452-468. [PMID: 28849613 DOI: 10.1111/tpj.13669] [Citation(s) in RCA: 154] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 08/05/2017] [Accepted: 08/11/2017] [Indexed: 05/04/2023]
Abstract
Allotetraploid oilseed rape (Brassica napus L.) is an agriculturally important crop. Cultivation and breeding of B. napus by humans has resulted in numerous genetically diverse morphotypes with optimized agronomic traits and ecophysiological adaptation. To further understand the genetic basis of diversification and adaptation, we report a draft genome of an Asian semi-winter oilseed rape cultivar 'ZS11' and its comprehensive genomic comparison with the genomes of the winter-type cultivar 'Darmor-bzh' as well as two progenitors. The integrated BAC-to-BAC and whole-genome shotgun sequencing strategies were effective in the assembly of repetitive regions (especially young long terminal repeats) and resulted in a high-quality genome assembly of B. napus 'ZS11'. Within a short evolutionary period (~6700 years ago), semi-winter-type 'ZS11' and the winter-type 'Darmor-bzh' maintained highly genomic collinearity. Even so, certain genetic differences were also detected in two morphotypes. Relative to 'Darmor-bzh', both two subgenomes of 'ZS11' are closely related to its progenitors, and the 'ZS11' genome harbored several specific segmental homoeologous exchanges (HEs). Furthermore, the semi-winter-type 'ZS11' underwent potential genomic introgressions with B. rapa (Ar ). Some of these genetic differences were associated with key agronomic traits. A key gene of A03.FLC3 regulating vernalization-responsive flowering time in 'ZS11' was first experienced HE, and then underwent genomic introgression event with Ar , which potentially has led to genetic differences in controlling vernalization in the semi-winter types. Our observations improved our understanding of the genetic diversity of different B. napus morphotypes and the cultivation history of semi-winter oilseed rape in Asia.
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Affiliation(s)
- Fengming Sun
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Guangyi Fan
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
- BGI-Qingdao, Qingdao, 266555, China
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, Macao, China
| | - Qiong Hu
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Yongming Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Mei Guan
- College of Agronomy, Hunan Agricultural University, Changsha, 410128, China
| | - Chaobo Tong
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Jiana Li
- College of Agronomy and Biotechnology, Southwest University, BeiBei District, Chongqing, 400715, China
| | - Dezhi Du
- Qinghai Academy of Agricultural and Forestry, National Key Laboratory Breeding Base for Innovation and Utilization of Plateau Crop Germplasm, Xining, 810016, China
| | - Cunkou Qi
- Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China
| | - Liangcai Jiang
- Shichun Academy of Agricultural Sciences, Chengdu, 610066, China
| | - Weiqing Liu
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Shunmou Huang
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Wenbin Chen
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Jingyin Yu
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Desheng Mei
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Jinling Meng
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Peng Zeng
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Jiaqin Shi
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Kede Liu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xi Wang
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Xinfa Wang
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Yan Long
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xinming Liang
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Zhiyong Hu
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Guodong Huang
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Caihua Dong
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - He Zhang
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Jun Li
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Yaolei Zhang
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Liangwei Li
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Chengcheng Shi
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Jiahao Wang
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Simon Ming-Yuen Lee
- State Key Laboratory of Quality Research in Chinese Medicine and Institute of Chinese Medical Sciences, Macao, China
| | - Chunyun Guan
- College of Agronomy, Hunan Agricultural University, Changsha, 410128, China
| | - Xun Xu
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
| | - Shengyi Liu
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Xin Liu
- Beijing Genome Institute-Shenzhen, Shenzhen, 518083, China
- BGI-Qingdao, Qingdao, 266555, China
| | - Boulos Chalhoub
- Institut National de Recherche Agronomique (INRA), Unité de Recherche en Génomique Végétale (URGV), UMR1165, Organization and Evolution of Plant Genomes (OEPG), 2 rue Gaston Crémieux, 91057, Evry, France
| | - Wei Hua
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Hanzhong Wang
- The Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture of the PRC, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
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16
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Mwathi MW, Gupta M, Atri C, Banga SS, Batley J, Mason AS. Segregation for fertility and meiotic stability in novel Brassica allohexaploids. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2017; 130:767-776. [PMID: 28097399 DOI: 10.1007/s00122-016-2850-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Accepted: 12/27/2016] [Indexed: 05/15/2023]
Abstract
Allohexaploid Brassica populations reveal ongoing segregation for fertility, while genotype influences fertility and meiotic stability. Creation of a new Brassica allohexaploid species is of interest for the development of a crop type with increased heterosis and adaptability. At present, no naturally occurring, meiotically stable Brassica allohexaploid exists, with little data available on chromosome behaviour and meiotic control in allohexaploid germplasm. In this study, 100 plants from the cross B. carinata × B. rapa (A2 allohexaploid population) and 69 plants from the cross (B. napus × B. carinata) × B. juncea (H2 allohexaploid population) were assessed for fertility and meiotic behaviour. Estimated pollen viability, self-pollinated seed set, number of seeds on the main shoot, number of pods on the main shoot, seeds per ten pods and plant height were measured for both the A2 and H2 populations and for a set of reference control cultivars. The H2 population had high segregation for pollen viability and meiotic stability, while the A2 population was characterised by low pollen fertility and a high level of chromosome loss. Both populations were taller, but had lower average fertility trait values than the control cultivar samples. The study also characterises fertility and meiotic chromosome behaviour in genotypes and progeny sets in heterozygous allotetraploid Brassica derived lines, and indicates that genotypes of the parents and H1 hybrids are affecting chromosome pairing and fertility phenotypes in the H2 population. The identification and characterisation of factors influencing stability in novel allohexaploid Brassica populations will assist in the development of this as a new crop species for food and agricultural benefit.
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Affiliation(s)
- Margaret W Mwathi
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
- School of Plant Biology, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia
| | - Mehak Gupta
- Department of Plant Breeding and Genetics, DBT Centre of Excellence on Brassicas, Punjab Agricultural University, Ludhiana, 141001, India
| | - Chaya Atri
- Department of Plant Breeding and Genetics, DBT Centre of Excellence on Brassicas, Punjab Agricultural University, Ludhiana, 141001, India
| | - Surinder S Banga
- Department of Plant Breeding and Genetics, DBT Centre of Excellence on Brassicas, Punjab Agricultural University, Ludhiana, 141001, India
| | - Jacqueline Batley
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, 4072, Australia
- School of Plant Biology, The University of Western Australia, 35 Stirling Hwy, Crawley, WA, 6009, Australia
| | - Annaliese S Mason
- School of Agriculture and Food Sciences, University of Queensland, Brisbane, QLD, 4072, Australia.
- Department of Plant Breeding, Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
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17
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Schiessl S, Huettel B, Kuehn D, Reinhardt R, Snowdon RJ. Targeted deep sequencing of flowering regulators in Brassica napus reveals extensive copy number variation. Sci Data 2017; 4:170013. [PMID: 28291231 PMCID: PMC5349243 DOI: 10.1038/sdata.2017.13] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 01/05/2017] [Indexed: 01/23/2023] Open
Abstract
Gene copy number variation (CNV) is increasingly implicated in control of complex trait networks, particularly in polyploid plants like rapeseed (Brassica napus L.) with an evolutionary history of genome restructuring. Here we performed sequence capture to assay nucleotide variation and CNV in a panel of central flowering time regulatory genes across a species-wide diversity set of 280 B. napus accessions. The genes were chosen based on prior knowledge from Arabidopsis thaliana and related Brassica species. Target enrichment was performed using the Agilent SureSelect technology, followed by Illumina sequencing. A bait (probe) pool was developed based on results of a preliminary experiment with representatives from different B. napus morphotypes. A very high mean target coverage of ~670x allowed reliable calling of CNV, single nucleotide polymorphisms (SNPs) and insertion-deletion (InDel) polymorphisms. No accession exhibited no CNV, and at least one homolog of every gene we investigated showed CNV in some accessions. Some CNV appear more often in specific morphotypes, indicating a role in diversification.
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Affiliation(s)
- Sarah Schiessl
- Department of Plant Breeding, Justus Liebig University, IFZ Research Centre for Biosystems, Land Use and Nutrition, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Bruno Huettel
- Max Planck Institute for Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Diana Kuehn
- Max Planck Institute for Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Richard Reinhardt
- Max Planck Institute for Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Rod J Snowdon
- Department of Plant Breeding, Justus Liebig University, IFZ Research Centre for Biosystems, Land Use and Nutrition, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
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18
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Pelé A, Trotoux G, Eber F, Lodé M, Gilet M, Deniot G, Falentin C, Nègre S, Morice J, Rousseau-Gueutin M, Chèvre AM. The poor lonesome A subgenome of Brassica napus var. Darmor (AACC) may not survive without its mate. THE NEW PHYTOLOGIST 2017; 213:1886-1897. [PMID: 27575298 DOI: 10.1111/nph.14147] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 07/12/2016] [Indexed: 06/06/2023]
Abstract
Constitutive genomes of allopolyploid species evolve throughout their life span. However, the consequences of long-term alterations on the interdependency between each original genome have not been established. Here, we attempted an approach corresponding to subgenome extraction from a previously sequenced natural allotetraploid, offering a unique opportunity to evaluate plant viability and structural evolution of one of its diploid components. We employed two different strategies to extract the diploid AA component of the Brassica napus variety 'Darmor' (AACC, 2n = 4x = 38) and we assessed the genomic structure of the latest AA plants obtained (after four to five rounds of selection), using a 60K single nucleotide polymorphism Illumina array. Only one strategy was successful and the diploid AA plants that were structurally characterized presented a lower proportion of the B. napus A subgenome extracted than expected. In addition, our analyses revealed that some genes lost in a polyploid context appeared to be compensated for plant survival, either by conservation of genomic regions from B. rapa, used in the initial cross, or by some introgressions from the B. napus C subgenome. We conclude that as little as c. 7500 yr of coevolution could lead to subgenome interdependency in the allotetraploid B. napus as a result of structural modifications.
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Affiliation(s)
- Alexandre Pelé
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, 35650, Le Rheu, France
| | - Gwenn Trotoux
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, 35650, Le Rheu, France
| | - Frédérique Eber
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, 35650, Le Rheu, France
| | - Maryse Lodé
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, 35650, Le Rheu, France
| | - Marie Gilet
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, 35650, Le Rheu, France
| | - Gwenaelle Deniot
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, 35650, Le Rheu, France
| | - Cyril Falentin
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, 35650, Le Rheu, France
| | - Sylvie Nègre
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, 35650, Le Rheu, France
| | - Jérôme Morice
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, 35650, Le Rheu, France
| | | | - Anne-Marie Chèvre
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, 35650, Le Rheu, France
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The Impact of Open Pollination on the Structural Evolutionary Dynamics, Meiotic Behavior, and Fertility of Resynthesized Allotetraploid Brassica napus L. G3-GENES GENOMES GENETICS 2017; 7:705-717. [PMID: 28007837 PMCID: PMC5295613 DOI: 10.1534/g3.116.036517] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Allopolyploidy, which results from the merger and duplication of two divergent genomes, has played a major role in the evolution and diversification of flowering plants. The genomic changes that occur in resynthesized or natural neopolyploids have been extensively studied, but little is known about the effects of the reproductive mode in the initial generations that may precede its successful establishment. To truly reflect the early generations of a nascent polyploid, two resynthesized allotetraploid Brassica napus populations were obtained for the first time by open pollination. In these populations, we detected a much lower level of aneuploidy (third generation) compared with those previously published populations obtained by controlled successive selfing. We specifically studied 33 resynthesized B. napus individuals from our two open pollinated populations, and showed that meiosis was affected in both populations. Their genomes were deeply shuffled after allopolyploidization: up to 8.5 and 3.5% of the C and A subgenomes were deleted in only two generations. The identified deletions occurred mainly at the distal part of the chromosome, and to a significantly greater extent on the C rather than the A subgenome. Using Fluorescent In Situ Hybridization (BAC-FISH), we demonstrated that four of these deletions corresponded to fixed translocations (via homeologous exchanges). We were able to evaluate the size of the structural variations and their impact on the whole genome size, gene content, and allelic diversity. In addition, the evolution of fertility was assessed, to better understand the difficulty encountered by novel polyploid individuals before the putative formation of a novel stable species.
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Schiessl S, Huettel B, Kuehn D, Reinhardt R, Snowdon R. Post-polyploidisation morphotype diversification associates with gene copy number variation. Sci Rep 2017; 7:41845. [PMID: 28165502 PMCID: PMC5292959 DOI: 10.1038/srep41845] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 01/03/2017] [Indexed: 11/24/2022] Open
Abstract
Genetic models for polyploid crop adaptation provide important information relevant for future breeding prospects. A well-suited model is Brassica napus, a recent allopolyploid closely related to Arabidopsis thaliana. Flowering time is a major adaptation trait determining life cycle synchronization with the environment. Here we unravel natural genetic variation in B. napus flowering time regulators and investigate associations with evolutionary diversification into different life cycle morphotypes. Deep sequencing of 35 flowering regulators was performed in 280 diverse B. napus genotypes. High sequencing depth enabled high-quality calling of single-nucleotide polymorphisms (SNPs), insertion-deletions (InDels) and copy number variants (CNVs). By combining these data with genotyping data from the Brassica 60 K Illumina® Infinium SNP array, we performed a genome-wide marker distribution analysis across the 4 ecogeographical morphotypes. Twelve haplotypes, including Bna.FLC.A10, Bna.VIN3.A02 and the Bna.FT promoter on C02_random, were diagnostic for the diversification of winter and spring types. The subspecies split between oilseed/kale (B. napus ssp. napus) and swedes/rutabagas (B. napus ssp. napobrassica) was defined by 13 haplotypes, including genomic rearrangements encompassing copies of Bna.FLC, Bna.PHYA and Bna.GA3ox1. De novo variation in copies of important flowering-time genes in B. napus arose during allopolyploidisation, enabling sub-functionalisation that allowed different morphotypes to appropriately fine-tune their lifecycle.
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Affiliation(s)
- Sarah Schiessl
- Department of Plant Breeding, Justus Liebig University, IFZ Research Centre for Biosystems, Land Use and Nutrition, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Bruno Huettel
- Max Planck Institute for Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Diana Kuehn
- Max Planck Institute for Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Richard Reinhardt
- Max Planck Institute for Breeding Research, Carl-von-Linné-Weg 10, 50829 Cologne, Germany
| | - Rod Snowdon
- Department of Plant Breeding, Justus Liebig University, IFZ Research Centre for Biosystems, Land Use and Nutrition, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
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21
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Zhou J, Tan C, Cui C, Ge X, Li Z. Distinct subgenome stabilities in synthesized Brassica allohexaploids. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2016; 129:1257-1271. [PMID: 26971112 DOI: 10.1007/s00122-016-2701-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 02/27/2016] [Indexed: 05/10/2023]
Abstract
Trigenomic Brassica allohexaploids synthesized from three crossing strategies showed diploidized and non-diploidized meiotic behaviors and produced both euploid and aneuploid progenies during successive generations, revealing the distinct subgenome stabilities (B > A> C). Three cultivated allotetraploid Brassica species (Brassica napus, B. juncea, B. carinata) represent the model system of speciation through interspecific hybridization and allopolyploidization, but no Brassica species at higher ploidy level exists in nature. In this study, Brassica allohexaploids (2n = 54, AABBCC) were artificially synthesized using three crossing strategies, and had combinations of the genomes from the extant allotetraploids and diploids (B. rapa, B. oleracea and B. nigra). The chromosome numbers and complements of these allohexaploids and the self-pollinated progenies of successive generations (S0-S7) were determined using multicolor fluorescent in situ hybridization that distinguished the chromosomes of three constituent genomes from each other. Both euploid and aneuploid progenies were identified. The most aneuploids maintained all B- and A-genome chromosomes and variable number of C-genome chromosomes, suggesting that genome stability was B > A > C. In the extreme case, loss of whole set of C-genome chromosomes led to the production of B. juncea-type progeny. Some aneuploid progenies had the same number of chromosomes (2n = 54) as the euploid, but the simultaneous loss and gain of A- and C-genome chromosomes. The diploidized and non-diploidized meiotic behaviors co-occurred in all allohexaploid individuals of consecutive generations. The aberrant chromosome pairing and segregation mainly involved the chromosomes of A and C genomes, which resulted in aneuploidy in self-pollinated progenies. The mechanisms for the differential stability of three genomes and the stabilization of the new allohexaploids are discussed.
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Affiliation(s)
- Jiannan Zhou
- National Key Lab of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Chen Tan
- National Key Lab of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Cheng Cui
- Crop Research Institute, Sichuan Academy of Agricultural Sciences, Chengdu, 610066, People's Republic of China
| | - Xianhong Ge
- National Key Lab of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China
| | - Zaiyun Li
- National Key Lab of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, 430070, People's Republic of China.
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Raman H, Raman R, Coombes N, Song J, Prangnell R, Bandaranayake C, Tahira R, Sundaramoorthi V, Killian A, Meng J, Dennis ES, Balasubramanian S. Genome-wide association analyses reveal complex genetic architecture underlying natural variation for flowering time in canola. PLANT, CELL & ENVIRONMENT 2016; 39:1228-39. [PMID: 26428711 DOI: 10.1111/pce.12644] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 09/17/2015] [Accepted: 09/20/2015] [Indexed: 05/17/2023]
Abstract
Optimum flowering time is the key to maximize canola production in order to meet global demand of vegetable oil, biodiesel and canola-meal. We reveal extensive variation in flowering time across diverse genotypes of canola under field, glasshouse and controlled environmental conditions. We conduct a genome-wide association study and identify 69 single nucleotide polymorphism (SNP) markers associated with flowering time, which are repeatedly detected across experiments. Several associated SNPs occur in clusters across the canola genome; seven of them were detected within 20 Kb regions of a priori candidate genes; FLOWERING LOCUS T, FRUITFUL, FLOWERING LOCUS C, CONSTANS, FRIGIDA, PHYTOCHROME B and an additional five SNPs were localized within 14 Kb of a previously identified quantitative trait loci for flowering time. Expression analyses showed that among FLC paralogs, BnFLC.A2 accounts for ~23% of natural variation in diverse accessions. Genome-wide association analysis for FLC expression levels mapped not only BnFLC.C2 but also other loci that contribute to variation in FLC expression. In addition to revealing the complex genetic architecture of flowering time variation, we demonstrate that the identified SNPs can be modelled to predict flowering time in diverse canola germplasm accurately and hence are suitable for genomic selection of adaptative traits in canola improvement programmes.
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Affiliation(s)
- H Raman
- Graham Centre for Agricultural Innovation (an alliance between NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, 2650, Australia
| | - R Raman
- Graham Centre for Agricultural Innovation (an alliance between NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, 2650, Australia
| | - N Coombes
- Graham Centre for Agricultural Innovation (an alliance between NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, 2650, Australia
| | - J Song
- Diversity Arrays Technology P/L, University of Canberra, Canberra, ACT, 2601, Australia
| | - R Prangnell
- Graham Centre for Agricultural Innovation (an alliance between NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, 2650, Australia
| | - C Bandaranayake
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - R Tahira
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - V Sundaramoorthi
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - A Killian
- Diversity Arrays Technology P/L, University of Canberra, Canberra, ACT, 2601, Australia
| | - J Meng
- National Key Laboratory of Crop Improvement, Huazhong Agricultural University, Wuhan, China
| | - E S Dennis
- CSIRO Division of Plant Industry, Canberra, ACT, 2601, Australia
| | - S Balasubramanian
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
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Zhang X, Liu T, Li X, Duan M, Wang J, Qiu Y, Wang H, Song J, Shen D. Interspecific hybridization, polyploidization, and backcross of Brassica oleracea var. alboglabra with B. rapa var. purpurea morphologically recapitulate the evolution of Brassica vegetables. Sci Rep 2016; 6:18618. [PMID: 26727246 PMCID: PMC4698638 DOI: 10.1038/srep18618] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 11/19/2015] [Indexed: 11/30/2022] Open
Abstract
Brassica oleracea and B. rapa are two important vegetable crops. Both are composed of dozens of subspecies encompassing hundreds of varieties and cultivars. Synthetic B. napus with these two plants has been used extensively as a research model for the investigation of allopolyploid evolution. However, the mechanism underlying the explosive evolution of hundreds of varieties of B. oleracea and B. rapa within a short period is poorly understood. In the present study, interspecific hybridization between B. oleracea var. alboglabra and B. rapa var. purpurea was performed. The backcross progeny displayed extensive morphological variation, including some individuals that phenocopied subspecies other than their progenitors. Numerous interesting novel phenotypes and mutants were identified among the backcross progeny. The chromosomal recombination between the A and C genomes and the chromosomal asymmetric segregation were revealed using Simple Sequence Repeats (SSR) markers. These findings provide direct evidence in support of the hypothesis that interspecific hybridization and backcrossing have played roles in the evolution of the vast variety of vegetables among these species and suggest that combination of interspecific hybridization and backcrossing may facilitate the development of new mutants and novel phenotypes for both basic research and the breeding of new vegetable crops.
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Affiliation(s)
- Xiaohui Zhang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Beijing, 100081, China
| | - Tongjin Liu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Beijing, 100081, China
| | - Xixiang Li
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Beijing, 100081, China
| | - Mengmeng Duan
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Beijing, 100081, China
| | - Jinglei Wang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Beijing, 100081, China
| | - Yang Qiu
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Beijing, 100081, China
| | - Haiping Wang
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Beijing, 100081, China
| | - Jiangping Song
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Beijing, 100081, China
| | - Di Shen
- Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences; Key Laboratory of Biology and Genetic Improvement of Horticultural Crops, Ministry of Agriculture, Beijing, 100081, China
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24
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Fu D, Mason AS, Xiao M, Yan H. Effects of genome structure variation, homeologous genes and repetitive DNA on polyploid crop research in the age of genomics. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2016; 242:37-46. [PMID: 26566823 DOI: 10.1016/j.plantsci.2015.09.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2015] [Revised: 09/10/2015] [Accepted: 09/22/2015] [Indexed: 06/05/2023]
Abstract
Compared to diploid species, allopolyploid crop species possess more complex genomes, higher productivity, and greater adaptability to changing environments. Next generation sequencing techniques have produced high-density genetic maps, whole genome sequences, transcriptomes and epigenomes for important polyploid crops. However, several problems interfere with the full application of next generation sequencing techniques to these crops. Firstly, different types of genomic variation affect sequence assembly and QTL mapping. Secondly, duplicated or homoeologous genes can diverge in function and then lead to emergence of many minor QTL, which increases difficulties in fine mapping, cloning and marker assisted selection. Thirdly, repetitive DNA sequences arising in polyploid crop genomes also impact sequence assembly, and are increasingly being shown to produce small RNAs to regulate gene expression and hence phenotypic traits. We propose that these three key features should be considered together when analyzing polyploid crop genomes. It is apparent that dissection of genomic structural variation, elucidation of the function and mechanism of interaction of homoeologous genes, and investigation of the de novo roles of repeat sequences in agronomic traits are necessary for genomics-based crop breeding in polyploids.
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Affiliation(s)
- Donghui Fu
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Agronomy College, Jiangxi Agricultural University, Nanchang 330045, China.
| | - Annaliese S Mason
- Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392 Giessen, Germany
| | - Meili Xiao
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Agronomy College, Jiangxi Agricultural University, Nanchang 330045, China
| | - Hui Yan
- Key Laboratory of Poyang Lake Basin Agricultural Resources and Ecology of Jiangxi Province, Jiangxi Agricultural University, Nanchang 330045, China
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25
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Mason AS, Takahira J, Atri C, Samans B, Hayward A, Cowling WA, Batley J, Nelson MN. Microspore culture reveals complex meiotic behaviour in a trigenomic Brassica hybrid. BMC PLANT BIOLOGY 2015; 15:173. [PMID: 26152188 PMCID: PMC4493989 DOI: 10.1186/s12870-015-0555-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 06/16/2015] [Indexed: 05/10/2023]
Abstract
BACKGROUND Development of synthetic allohexaploid Brassica (2n = AABBCC) would be beneficial for agriculture, as allelic contributions from three genomes could increase hybrid vigour and broaden adaptation. Microspore culture of a near-allohexaploid hybrid derived from the cross (B. napus × B. carinata) × B. juncea was undertaken in order to assess the frequency and distribution of homologous and homoeologous crossovers in this trigenomic hybrid. SNP and SSR molecular markers were used to detect inheritance of A, B and C genome alleles in microspore-derived (MD) progeny. SNP allele copy number was also assessed. The MD progeny were also compared to progeny derived by self-pollination and open-pollination for fertility (estimated by self-pollinated seed set and pollen viability) and DNA ploidy (measured by flow cytometry). RESULTS In the trigenomic hybrid, homologous chromosome pairs A(j)-A(n), B(j)-B(c) and C(n)-C(c) had similar meiotic crossover frequencies and segregation to that previously observed in established Brassica species, as demonstrated by marker haplotype analysis of the MD population. Homoeologous pairing between chromosomes A1-C1, A2-C2 and A7-C6 was detected at frequencies of 12-18 %, with other homoeologous chromosome regions associating from 8 % (A3-C3) to 0-1 % (A8-C8, A8-C9) of the time. Copy number analysis revealed eight instances of additional chromosomes and 20 instances of chromosomes present in one copy in somatically doubled MD progeny. Presence of chromosome A6 was positively correlated with self-pollinated seed set and pollen viability in the MD population. Many MD progeny were unable to produce self-pollinated seed (76 %) or viable pollen (53 %), although one MD plant produced 198 self-pollinated seeds. Average fertility was significantly lower in progeny obtained by microspore culture than progeny obtained by self-pollination or open-pollination, after excluding MD progeny which had not undergone chromosome doubling. CONCLUSIONS Based on SNP data analysis of the microspore-derived progeny, crossover frequency per chromosome in the allohexaploid hybrid was found to be similar to that in established Brassica species, suggesting that the higher chromosome number did not significantly disrupt cellular regulation of meiosis. SNP allele copy number analysis revealed the occurrence not only of homoeologous duplication/deletion events but also other cryptic duplications and deletions that may have been the result of mitotic instability. Microspore culture simplified the assessment of chromosome behaviour in the allohexaploid hybrid but yielded progeny with lower fertility and a greater range of ploidy levels compared to progeny obtained by self- or open-pollination.
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Affiliation(s)
- Annaliese S Mason
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, 4072, Australia.
- Centre for Integrative Legume Research, The University of Queensland, Brisbane, 4072, Australia.
- Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
| | - Junko Takahira
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, Perth, Australia.
| | - Chhaya Atri
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, Perth, Australia.
- Plant Breeding & Genetics Department, Punjab Agricultural University, Ferozepur Road, Ludhiana, Punjab, 141004, India.
| | - Birgit Samans
- Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Heinrich-Buff-Ring 26-32, 35392, Giessen, Germany.
| | - Alice Hayward
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, 4072, Australia.
- Centre for Integrative Legume Research, The University of Queensland, Brisbane, 4072, Australia.
| | - Wallace A Cowling
- The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, Perth, Australia.
| | - Jacqueline Batley
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, 4072, Australia.
- Centre for Integrative Legume Research, The University of Queensland, Brisbane, 4072, Australia.
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, Perth, Australia.
| | - Matthew N Nelson
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, Perth, Australia.
- The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, Perth, Australia.
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26
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Zhang D, Pan Q, Cui C, Tan C, Ge X, Shao Y, Li Z. Genome-specific differential gene expressions in resynthesized Brassica allotetraploids from pair-wise crosses of three cultivated diploids revealed by RNA-seq. FRONTIERS IN PLANT SCIENCE 2015; 6:957. [PMID: 26583027 PMCID: PMC4631939 DOI: 10.3389/fpls.2015.00957] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2015] [Accepted: 10/20/2015] [Indexed: 05/18/2023]
Abstract
Polyploidy is popular for the speciation of angiosperms but the initial stage of allopolyploidization resulting from interspecific hybridization and genome duplication is associated with different extents of changes in genome structure and gene expressions. Herein, the transcriptomes detected by RNA-seq in resynthesized Brassica allotetraploids (Brassica juncea, AABB; B. napus, AACC; B. carinata, BBCC) from the pair-wise crosses of the same three diploids (B. rapa, AA; B. nigra, BB; B. oleracea, CC) were compared to reveal the patterns of gene expressions from progenitor genomes and the effects of different types of genome combinations and cytoplasm, upon the genome merger and duplication. From transcriptomic analyses for leaves and silique walls, extensive expression alterations were revealed in these resynthesized allotetraploids relative to their diploid progenitors, as well as during the transition from vegetative to reproductive development, for differential and transgressive gene expressions were variable in numbers and functions. Genes involved in glucosinolates and DNA methylation were transgressively up-regulated among most samples, suggesting that gene expression regulation was immediately established after allopolyploidization. The expression of ribosomal protein genes was also tissue-specific and showed a similar expression hierarchy of rRNA genes. The balance between the co-up and co-down regulation was observed between reciprocal B. napus with different types of the cytoplasm. Our results suggested that gene expression changes occurred after initial genome merger and such profound alterations might enhance the growth vigor and adaptability of Brassica allotetraploids.
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Affiliation(s)
- Dawei Zhang
- National Key Lab of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Qi Pan
- National Key Lab of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Cheng Cui
- Crop Research Institute, Sichuan Academy of Agricultural SciencesChengdu, China
| | - Chen Tan
- National Key Lab of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Xianhong Ge
- National Key Lab of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Yujiao Shao
- College of Chemistry and Life Science, Hubei University of EducationWuhan, China
- *Correspondence: Yujiao Shao
| | - Zaiyun Li
- National Key Lab of Crop Genetic Improvement, National Center of Crop Molecular Breeding Technology, National Center of Oil Crop Improvement (Wuhan), College of Plant Science and Technology, Huazhong Agricultural UniversityWuhan, China
- Zaiyun Li
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27
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Raman H, Dalton-Morgan J, Diffey S, Raman R, Alamery S, Edwards D, Batley J. SNP markers-based map construction and genome-wide linkage analysis in Brassica napus. PLANT BIOTECHNOLOGY JOURNAL 2014; 12:851-60. [PMID: 24698362 DOI: 10.1111/pbi.12186] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Revised: 01/29/2014] [Accepted: 02/21/2014] [Indexed: 05/19/2023]
Abstract
An Illumina Infinium array comprising 5306 single nucleotide polymorphism (SNP) markers was used to genotype 175 individuals of a doubled haploid population derived from a cross between Skipton and Ag-Spectrum, two Australian cultivars of rapeseed (Brassica napus L.). A genetic linkage map based on 613 SNP and 228 non-SNP (DArT, SSR, SRAP and candidate gene markers) covering 2514.8 cM was constructed and further utilized to identify loci associated with flowering time and resistance to blackleg, a disease caused by the fungus Leptosphaeria maculans. Comparison between genetic map positions of SNP markers and the sequenced Brassica rapa (A) and Brassica oleracea (C) genome scaffolds showed several genomic rearrangements in the B. napus genome. A major locus controlling resistance to L. maculans was identified at both seedling and adult plant stages on chromosome A07. QTL analyses revealed that up to 40.2% of genetic variation for flowering time was accounted for by loci having quantitative effects. Comparative mapping showed Arabidopsis and Brassica flowering genes such as Phytochrome A/D, Flowering Locus C and agamous-Like MADS box gene AGL1 map within marker intervals associated with flowering time in a DH population from Skipton/Ag-Spectrum. Genomic regions associated with flowering time and resistance to L. maculans had several SNP markers mapped within 10 cM. Our results suggest that SNP markers will be suitable for various applications such as trait introgression, comparative mapping and high-resolution mapping of loci in B. napus.
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Affiliation(s)
- Harsh Raman
- Graham Centre for Agricultural Innovation (an alliance between NSW Department of Primary Industries and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW, Australia
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Mason AS, Batley J, Bayer PE, Hayward A, Cowling WA, Nelson MN. High-resolution molecular karyotyping uncovers pairing between ancestrally related Brassica chromosomes. THE NEW PHYTOLOGIST 2014; 202:964-974. [PMID: 24471809 DOI: 10.1111/nph.12706] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Accepted: 12/20/2013] [Indexed: 05/18/2023]
Abstract
How do chromosomal regions with differing degrees of homology and homeology interact at meiosis? We provide a novel analytical method based on simple genetics principles which can help to answer this important question. This method interrogates high-throughput molecular marker data in order to infer chromosome behavior at meiosis in interspecific hybrids. We validated this method using high-resolution molecular marker karyotyping in two experimental Brassica populations derived from interspecific crosses among B. juncea, B. napus and B. carinata, using a single nucleotide polymorphism chip. This method of analysis successfully identified meiotic interactions between chromosomes sharing different degrees of similarity: full-length homologs; full-length homeologs; large sections of primary homeologs; and small sections of secondary homeologs. This analytical method can be applied to any allopolyploid species or fertile interspecific hybrid in order to detect meiotic associations. This genetic information can then be used to identify which genomic regions share functional homeology (i.e., retain enough similarity to allow pairing and segregation at meiosis). When applied to interspecific hybrids for which reference genome sequences are available, the question of how differing degrees of homology and homeology affect meiotic interactions may finally be resolved.
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Affiliation(s)
- Annaliese S Mason
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, 4072, Qld, Australia
- Centre for Integrative Legume Research, The University of Queensland, Brisbane, 4072, Qld, Australia
| | - Jacqueline Batley
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, 4072, Qld, Australia
- Centre for Integrative Legume Research, The University of Queensland, Brisbane, 4072, Qld, Australia
| | - Philipp Emanuel Bayer
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, 4072, Qld, Australia
- Australian Centre for Plant Functional Genomics, The University of Queensland, Brisbane, 4072, Qld, Australia
| | - Alice Hayward
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane, 4072, Qld, Australia
- Centre for Integrative Legume Research, The University of Queensland, Brisbane, 4072, Qld, Australia
| | - Wallace A Cowling
- The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, WA, Australia
| | - Matthew N Nelson
- The UWA Institute of Agriculture, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, WA, Australia
- School of Plant Biology, The University of Western Australia, 35 Stirling Highway, Crawley, 6009, WA, Australia
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Abstract
Production of allohexaploid Brassica (2n = AABBCC) is a promising goal for plant breeders due to the potential for hybrid heterosis and useful allelic contributions from all three of the Brassica genomes present in the cultivated diploid (2n = AA, 2n = BB, 2n = CC) and allotetraploid (2n = AABB, 2n = AACC, and 2n = BBCC) crop species (canola, cabbages, mustards). We used high-throughput SNP molecular marker assays, flow cytometry, and fluorescent in situ hybridization (FISH) to characterize a population of putative allohexaploids derived from self-pollination of a hybrid from the novel cross (B. napus × B. carinata) × B. juncea to investigate whether fertile, stable allohexaploid Brassica can be produced. Allelic segregation in the A and C genomes generally followed Mendelian expectations for an F2 population, with minimal nonhomologous chromosome pairing. However, we detected no strong selection for complete 2n = AABBCC chromosome complements, with weak correlations between DNA content and fertility (r(2) = 0.11) and no correlation between missing chromosomes or chromosome segments and fertility. Investigation of next-generation progeny resulting from one highly fertile F2 plant using FISH revealed general maintenance of high chromosome numbers but severe distortions in karyotype, as evidenced by recombinant chromosomes and putative loss/duplication of A- and C-genome chromosome pairs. Our results show promise for the development of meiotically stable allohexaploid lines, but highlight the necessity of selection for 2n = AABBCC karyotypes.
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Raman H, Raman R, Kilian A, Detering F, Long Y, Edwards D, Parkin IAP, Sharpe AG, Nelson MN, Larkan N, Zou J, Meng J, Aslam MN, Batley J, Cowling WA, Lydiate D. A consensus map of rapeseed (Brassica napus L.) based on diversity array technology markers: applications in genetic dissection of qualitative and quantitative traits. BMC Genomics 2013; 14:277. [PMID: 23617817 PMCID: PMC3641989 DOI: 10.1186/1471-2164-14-277] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2012] [Accepted: 04/06/2013] [Indexed: 12/03/2022] Open
Abstract
Background Dense consensus genetic maps based on high-throughput genotyping platforms are valuable for making genetic gains in Brassica napus through quantitative trait locus identification, efficient predictive molecular breeding, and map-based gene cloning. This report describes the construction of the first B. napus consensus map consisting of a 1,359 anchored array based genotyping platform; Diversity Arrays Technology (DArT), and non-DArT markers from six populations originating from Australia, Canada, China and Europe. We aligned the B. napus DArT sequences with genomic scaffolds from Brassica rapa and Brassica oleracea, and identified DArT loci that showed linkage with qualitative and quantitative loci associated with agronomic traits. Results The integrated consensus map covered a total of 1,987.2 cM and represented all 19 chromosomes of the A and C genomes, with an average map density of one marker per 1.46 cM, corresponding to approximately 0.88 Mbp of the haploid genome. Through in silico physical mapping 2,457 out of 3,072 (80%) DArT clones were assigned to the genomic scaffolds of B. rapa (A genome) and B. oleracea (C genome). These were used to orientate the genetic consensus map with the chromosomal sequences. The DArT markers showed linkage with previously identified non-DArT markers associated with qualitative and quantitative trait loci for plant architecture, phenological components, seed and oil quality attributes, boron efficiency, sucrose transport, male sterility, and race-specific resistance to blackleg disease. Conclusions The DArT markers provide increased marker density across the B. napus genome. Most of the DArT markers represented on the current array were sequenced and aligned with the B. rapa and B. oleracea genomes, providing insight into the Brassica A and C genomes. This information can be utilised for comparative genomics and genomic evolution studies. In summary, this consensus map can be used to (i) integrate new generation markers such as SNP arrays and next generation sequencing data; (ii) anchor physical maps to facilitate assembly of B. napus genome sequences; and (iii) identify candidate genes underlying natural genetic variation for traits of interest.
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Affiliation(s)
- Harsh Raman
- EH Graham Centre for Agricultural Innovation (an alliance between NSWDPI and Charles Sturt University), Wagga Wagga Agricultural Institute, Wagga Wagga, NSW 2650, Australia
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Persistent whole-chromosome aneuploidy is generally associated with nascent allohexaploid wheat. Proc Natl Acad Sci U S A 2013; 110:3447-52. [PMID: 23401544 DOI: 10.1073/pnas.1300153110] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Allopolyploidization has been a driving force in plant evolution. Formation of common wheat (Triticum aestivum L.) represents a classic example of successful speciation via allopolyploidy. Nevertheless, the immediate chromosomal consequences of allopolyploidization in wheat remain largely unexplored. We report here an in-depth investigation on transgenerational chromosomal variation in resynthesized allohexaploid wheats that are identical in genome constitution to common wheat. We deployed sequential FISH, genomic in situ hybridization (GISH), and homeolog-specific pyrosequencing, which enabled unequivocal identification of each of the 21 homologous chromosome pairs in each of >1,000 individual plants from 16 independent lines. We report that whole-chromosome aneuploidy occurred ubiquitously in early generations (from selfed generation S(1) to >S(20)) of wheat allohexaploidy although at highly variable frequencies (20-100%). In contrast, other types of gross structural variations were scant. Aneuploidy included an unexpected hidden type, which had a euploid chromosome number of 2n = 42 but with simultaneous loss and gain of nonhomeologous chromosomes. Of the three constituent subgenomes, B showed the most lability for aneuploidy, followed by A, but the recently added D subgenome was largely stable in most of the studied lines. Chromosome loss and gain were also unequal across the 21 homologous chromosome pairs. Pedigree analysis showed no evidence for progressive karyotype stabilization even with multigenerational selection for euploidy. Profiling of two traits directly related to reproductive fitness showed that although pollen viability was generally reduced by aneuploidy, the adverse effect of aneuploidy on seed-set is dependent on both aneuploidy type and synthetic line.
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Grover CE, Gallagher JP, Szadkowski EP, Yoo MJ, Flagel LE, Wendel JF. Homoeolog expression bias and expression level dominance in allopolyploids. THE NEW PHYTOLOGIST 2012; 196:966-971. [PMID: 23033870 DOI: 10.1111/j.1469-8137.2012.04365.x] [Citation(s) in RCA: 166] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Affiliation(s)
- C E Grover
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
| | - J P Gallagher
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
| | - E P Szadkowski
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
| | - M J Yoo
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
| | - L E Flagel
- Department of Biology, Duke University, Durham, NC, 27708, USA
| | - J F Wendel
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, 50011, USA
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