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Salojärvi J, Rambani A, Yu Z, Guyot R, Strickler S, Lepelley M, Wang C, Rajaraman S, Rastas P, Zheng C, Muñoz DS, Meidanis J, Paschoal AR, Bawin Y, Krabbenhoft TJ, Wang ZQ, Fleck SJ, Aussel R, Bellanger L, Charpagne A, Fournier C, Kassam M, Lefebvre G, Métairon S, Moine D, Rigoreau M, Stolte J, Hamon P, Couturon E, Tranchant-Dubreuil C, Mukherjee M, Lan T, Engelhardt J, Stadler P, Correia De Lemos SM, Suzuki SI, Sumirat U, Wai CM, Dauchot N, Orozco-Arias S, Garavito A, Kiwuka C, Musoli P, Nalukenge A, Guichoux E, Reinout H, Smit M, Carretero-Paulet L, Filho OG, Braghini MT, Padilha L, Sera GH, Ruttink T, Henry R, Marraccini P, Van de Peer Y, Andrade A, Domingues D, Giuliano G, Mueller L, Pereira LF, Plaisance S, Poncet V, Rombauts S, Sankoff D, Albert VA, Crouzillat D, de Kochko A, Descombes P. The genome and population genomics of allopolyploid Coffea arabica reveal the diversification history of modern coffee cultivars. Nat Genet 2024; 56:721-731. [PMID: 38622339 PMCID: PMC11018527 DOI: 10.1038/s41588-024-01695-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 02/23/2024] [Indexed: 04/17/2024]
Abstract
Coffea arabica, an allotetraploid hybrid of Coffea eugenioides and Coffea canephora, is the source of approximately 60% of coffee products worldwide, and its cultivated accessions have undergone several population bottlenecks. We present chromosome-level assemblies of a di-haploid C. arabica accession and modern representatives of its diploid progenitors, C. eugenioides and C. canephora. The three species exhibit largely conserved genome structures between diploid parents and descendant subgenomes, with no obvious global subgenome dominance. We find evidence for a founding polyploidy event 350,000-610,000 years ago, followed by several pre-domestication bottlenecks, resulting in narrow genetic variation. A split between wild accessions and cultivar progenitors occurred ~30.5 thousand years ago, followed by a period of migration between the two populations. Analysis of modern varieties, including lines historically introgressed with C. canephora, highlights their breeding histories and loci that may contribute to pathogen resistance, laying the groundwork for future genomics-based breeding of C. arabica.
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Affiliation(s)
- Jarkko Salojärvi
- School of Biological Sciences, Nanyang Technological University, Singapore, Singapore.
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland.
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, Singapore.
| | - Aditi Rambani
- Boyce Thompson Institute, Cornell University, Ithaca, NY, USA
| | - Zhe Yu
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada
| | - Romain Guyot
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France
- Department of Electronics and Automation, Universidad Autónoma de Manizales, Manizales, Colombia
| | - Susan Strickler
- Boyce Thompson Institute, Cornell University, Ithaca, NY, USA
| | - Maud Lepelley
- Société des Produits Nestlé SA, Nestlé Research, Tours, France
| | - Cui Wang
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Sitaram Rajaraman
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, Helsinki, Finland
| | - Pasi Rastas
- Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Chunfang Zheng
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada
| | - Daniella Santos Muñoz
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada
| | - João Meidanis
- Institute of Computing, University of Campinas, Campinas, Brazil
| | - Alexandre Rossi Paschoal
- Department of Computer Science, The Federal University of Technology - Paraná (UTFPR), Cornélio Procópio, Brazil
| | - Yves Bawin
- Plant Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Melle, Belgium
| | | | - Zhen Qin Wang
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA
| | - Steven J Fleck
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA
| | - Rudy Aussel
- Société des Produits Nestlé SA, Nestlé Research, Tours, France
- Centre d'Immunologie de Marseille-Luminy, Aix Marseille Université, Marseille, France
| | | | - Aline Charpagne
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Coralie Fournier
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Mohamed Kassam
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Gregory Lefebvre
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Sylviane Métairon
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Déborah Moine
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Michel Rigoreau
- Société des Produits Nestlé SA, Nestlé Research, Tours, France
| | - Jens Stolte
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland
| | - Perla Hamon
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France
| | - Emmanuel Couturon
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France
| | | | - Minakshi Mukherjee
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA
| | - Tianying Lan
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA
| | - Jan Engelhardt
- Department of Computer Science, University of Leipzig, Leipzig, Germany
| | - Peter Stadler
- Department of Computer Science, University of Leipzig, Leipzig, Germany
- Interdisciplinary Center for Bioinformatics, University of Leipzig, Leipzig, Germany
| | | | | | - Ucu Sumirat
- Indonesian Coffee and Cocoa Research Institute (ICCRI), Jember, Indonesia
| | - Ching Man Wai
- University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Nicolas Dauchot
- Research Unit in Plant Cellular and Molecular Biology, University of Namur, Namur, Belgium
| | - Simon Orozco-Arias
- Department of Electronics and Automation, Universidad Autónoma de Manizales, Manizales, Colombia
| | - Andrea Garavito
- Departamento de Ciencias Biológicas, Facultad de Ciencias Exactas y Naturales, Universidad de Caldas, Manizales, Colombia
| | - Catherine Kiwuka
- National Agricultural Research Organization (NARO), Entebbe, Uganda
| | - Pascal Musoli
- National Agricultural Research Organization (NARO), Entebbe, Uganda
| | - Anne Nalukenge
- National Agricultural Research Organization (NARO), Entebbe, Uganda
| | - Erwan Guichoux
- Biodiversité Gènes & Communautés, INRA, Bordeaux, France
| | | | - Martin Smit
- Hortus Botanicus Amsterdam, Amsterdam, the Netherlands
| | | | - Oliveiro Guerreiro Filho
- Instituto Agronômico (IAC) Centro de Café 'Alcides Carvalho', Fazenda Santa Elisa, Campinas, Brazil
| | - Masako Toma Braghini
- Instituto Agronômico (IAC) Centro de Café 'Alcides Carvalho', Fazenda Santa Elisa, Campinas, Brazil
| | - Lilian Padilha
- Embrapa Café/Instituto Agronômico (IAC) Centro de Café 'Alcides Carvalho', Fazenda Santa Elisa, Campinas, Brazil
| | | | - Tom Ruttink
- Plant Sciences Unit, Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Melle, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Robert Henry
- Queensland Alliance for Agriculture and Food Innovation, University of Queensland, Brisbane, Queensland, Australia
| | - Pierre Marraccini
- CIRAD - UMR DIADE (IRD-CIRAD-Université de Montpellier) BP 64501, Montpellier, France
| | - Yves Van de Peer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- College of Horticulture, Academy for Advanced Interdisciplinary Studies, Nanjing Agricultural University, Nanjing, China
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - Alan Andrade
- Embrapa Café/Inovacafé Laboratory of Molecular Genetics Campus da UFLA-MG, Lavras, Brazil
| | - Douglas Domingues
- Group of Genomics and Transcriptomes in Plants, São Paulo State University, UNESP, Rio Claro, Brazil
| | - Giovanni Giuliano
- Italian National Agency for New Technologies, Energy and Sustainable Economic Development, ENEA Casaccia Research Center, Rome, Italy
| | - Lukas Mueller
- Boyce Thompson Institute, Cornell University, Ithaca, NY, USA
| | - Luiz Filipe Pereira
- Embrapa Café/Lab. Biotecnologia, Área de Melhoramento Genético, Londrina, Brazil
| | | | - Valerie Poncet
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France
| | - Stephane Rombauts
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Center for Plant Systems Biology, VIB, Ghent, Belgium
| | - David Sankoff
- Department of Mathematics and Statistics, University of Ottawa, Ottawa, Ontario, Canada
| | - Victor A Albert
- Department of Biological Sciences, University at Buffalo, Buffalo, NY, USA.
| | | | - Alexandre de Kochko
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France.
| | - Patrick Descombes
- Société des Produits Nestlé SA, Nestlé Research, Lausanne, Switzerland.
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de Tomás C, Vicient CM. The Genomic Shock Hypothesis: Genetic and Epigenetic Alterations of Transposable Elements after Interspecific Hybridization in Plants. EPIGENOMES 2023; 8:2. [PMID: 38247729 PMCID: PMC10801548 DOI: 10.3390/epigenomes8010002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Revised: 12/21/2023] [Accepted: 12/24/2023] [Indexed: 01/23/2024] Open
Abstract
Transposable elements (TEs) are major components of plant genomes with the ability to change their position in the genome or to create new copies of themselves in other positions in the genome. These can cause gene disruption and large-scale genomic alterations, including inversions, deletions, and duplications. Host organisms have evolved a set of mechanisms to suppress TE activity and counter the threat that they pose to genome integrity. These includes the epigenetic silencing of TEs mediated by a process of RNA-directed DNA methylation (RdDM). In most cases, the silencing machinery is very efficient for the vast majority of TEs. However, there are specific circumstances in which TEs can evade such silencing mechanisms, for example, a variety of biotic and abiotic stresses or in vitro culture. Hybridization is also proposed as an inductor of TE proliferation. In fact, the discoverer of the transposons, Barbara McClintock, first hypothesized that interspecific hybridization provides a "genomic shock" that inhibits the TE control mechanisms leading to the mobilization of TEs. However, the studies carried out on this topic have yielded diverse results, showing in some cases a total absence of mobilization or being limited to only some TE families. Here, we review the current knowledge about the impact of interspecific hybridization on TEs in plants and the possible implications of changes in the epigenetic mechanisms.
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Affiliation(s)
| | - Carlos M. Vicient
- Centre for Research in Agricultural Genomics, CRAG (CSIC-IRTA-UAB-UB), Campus UAB, Cerdanyola del Vallès, 08193 Barcelona, Spain
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Martin SL, Lujan Toro B, James T, Sauder CA, Laforest M. Insights from the genomes of 4 diploid Camelina spp. G3 (BETHESDA, MD.) 2022; 12:jkac182. [PMID: 35976116 PMCID: PMC9713399 DOI: 10.1093/g3journal/jkac182] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 06/12/2022] [Indexed: 11/12/2022]
Abstract
Plant evolution has been a complex process involving hybridization and polyploidization making understanding the origin and evolution of a plant's genome challenging even once a published genome is available. The oilseed crop, Camelina sativa (Brassicaceae), has a fully sequenced allohexaploid genome with 3 unknown ancestors. To better understand which extant species best represent the ancestral genomes that contributed to C. sativa's formation, we sequenced and assembled chromosome level draft genomes for 4 diploid members of Camelina: C. neglecta C. hispida var. hispida, C. hispida var. grandiflora, and C. laxa using long and short read data scaffolded with proximity data. We then conducted phylogenetic analyses on regions of synteny and on genes described for Arabidopsis thaliana, from across each nuclear genome and the chloroplasts to examine evolutionary relationships within Camelina and Camelineae. We conclude that C. neglecta is closely related to C. sativa's sub-genome 1 and that C. hispida var. hispida and C. hispida var. grandiflora are most closely related to C. sativa's sub-genome 3. Further, the abundance and density of transposable elements, specifically Helitrons, suggest that the progenitor genome that contributed C. sativa's sub-genome 3 maybe more similar to the genome of C. hispida var. hispida than that of C. hispida var. grandiflora. These diploid genomes show few structural differences when compared to C. sativa's genome indicating little change to chromosome structure following allopolyploidization. This work also indicates that C. neglecta and C. hispida are important resources for understanding the genetics of C. sativa and potential resources for crop improvement.
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Affiliation(s)
- Sara L Martin
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A 0CA, Canada
| | - Beatriz Lujan Toro
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A 0CA, Canada
| | - Tracey James
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A 0CA, Canada
| | - Connie A Sauder
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A 0CA, Canada
| | - Martin Laforest
- Saint-Jean-sur-Richelieu Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada
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4
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Jia L, Yang Y, Zhai H, He S, Xin G, Zhao N, Zhang H, Gao S, Liu Q. Production and characterization of a novel interspecific somatic hybrid combining drought tolerance and high quality of sweet potato and Ipomoea triloba L. PLANT CELL REPORTS 2022; 41:2159-2171. [PMID: 35943560 DOI: 10.1007/s00299-022-02912-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Accepted: 07/26/2022] [Indexed: 06/15/2023]
Abstract
A novel interspecific somatic hybrid combining drought tolerance and high quality of sweet potato and Ipomoea triloba L. was obtained and its genetic and epigenetic variations were studied. Somatic hybridization can be used to overcome the cross-incompatibility between sweet potato (Ipomoea batatas (L.) Lam.) and its wild relatives and transfer useful and desirable genes from wild relatives to cultivated plants. However, most of the interspecific somatic hybrids obtained to date cannot produce storage roots and do not exhibit agronomic characters. In the present study, a novel interspecific somatic hybrid, named XT1, was obtained through protoplast fusion between sweet potato cv. Xushu 18 and its wild relative I. triloba. This somatic hybrid produced storage roots and exhibited significantly higher drought tolerance and quality compared with its cultivated parent Xushu 18. Transcriptome and real-time quantitative PCR (qRT-PCR) analyses revealed that the well-known drought stress-responsive genes in XT1 and I. triloba were significantly up-regulated under drought stress. The genomic structural reconstructions between the two genomes of the fusion parents in XT1 were confirmed using genomic in situ hybridization (GISH) and specific nuclear and cytoplasmic DNA markers. The DNA methylation variations were characterized by methylation-sensitive amplified polymorphism (MSAP). This study not only reveals the significance of somatic hybridization in the genetic improvement of sweet potato but also provides valuable materials and knowledge for further investigating the mechanism of storage root formation in sweet potato.
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Affiliation(s)
- Licong Jia
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
- Institute of Grain and Oil Crops, Yantai Academy of Agricultural Sciences, Yantai, 265500, China
| | - Yufeng Yang
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Hong Zhai
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Shaozhen He
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Guosheng Xin
- Institute of Grain and Oil Crops, Yantai Academy of Agricultural Sciences, Yantai, 265500, China
| | - Ning Zhao
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Huan Zhang
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Shaopei Gao
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Qingchang Liu
- Key Laboratory of Sweet Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs/Beijing Key Laboratory of Crop Genetic Improvement/Laboratory of Crop Heterosis & Utilization and Joint Laboratory for International Cooperation in Crop Molecular Breeding, Ministry of Education, College of Agronomy & Biotechnology, China Agricultural University, Beijing, 100193, China.
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5
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Scarlett VT, Lovell JT, Shao M, Phillips J, Shu S, Lusinska J, Goodstein DM, Jenkins J, Grimwood J, Barry K, Chalhoub B, Schmutz J, Hasterok R, Catalán P, Vogel JP. Multiple origins, one evolutionary trajectory: gradual evolution characterizes distinct lineages of allotetraploid Brachypodium. Genetics 2022; 223:6758249. [PMID: 36218464 PMCID: PMC9910409 DOI: 10.1093/genetics/iyac146] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 09/16/2022] [Indexed: 11/13/2022] Open
Abstract
The "genomic shock" hypothesis posits that unusual challenges to genome integrity such as whole genome duplication may induce chaotic genome restructuring. Decades of research on polyploid genomes have revealed that this is often, but not always the case. While some polyploids show major chromosomal rearrangements and derepression of transposable elements in the immediate aftermath of whole genome duplication, others do not. Nonetheless, all polyploids show gradual diploidization over evolutionary time. To evaluate these hypotheses, we produced a chromosome-scale reference genome for the natural allotetraploid grass Brachypodium hybridum, accession "Bhyb26." We compared 2 independently derived accessions of B. hybridum and their deeply diverged diploid progenitor species Brachypodium stacei and Brachypodium distachyon. The 2 B. hybridum lineages provide a natural timecourse in genome evolution because one formed 1.4 million years ago, and the other formed 140 thousand years ago. The genome of the older lineage reveals signs of gradual post-whole genome duplication genome evolution including minor gene loss and genome rearrangement that are missing from the younger lineage. In neither B. hybridum lineage do we find signs of homeologous recombination or pronounced transposable element activation, though we find evidence supporting steady post-whole genome duplication transposable element activity in the older lineage. Gene loss in the older lineage was slightly biased toward 1 subgenome, but genome dominance was not observed at the transcriptomic level. We propose that relaxed selection, rather than an abrupt genomic shock, drives evolutionary novelty in B. hybridum, and that the progenitor species' similarity in transposable element load may account for the subtlety of the observed genome dominance.
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Affiliation(s)
- Virginia T Scarlett
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA,Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - John T Lovell
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Mingqin Shao
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | - Jeremy Phillips
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | - Shengqiang Shu
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | | | - David M Goodstein
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | - Jerry Jenkins
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Jane Grimwood
- Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Kerrie Barry
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA
| | | | - Jeremy Schmutz
- U.S. Dept. of Energy Joint Genome Institute, Berkeley, CA 94720, USA,Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | | | | | - John P Vogel
- Corresponding author: U.S. Dept. of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA 94720, USA.
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6
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Fukai E, Yoshikawa M, Shah N, Sandal N, Miyao A, Ono S, Hirakawa H, Akyol TY, Umehara Y, Nonomura KI, Stougaard J, Hirochika H, Hayashi M, Sato S, Andersen SU, Okazaki K. Widespread and transgenerational retrotransposon activation in inter- and intraspecies recombinant inbred populations of Lotus japonicus. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:1397-1410. [PMID: 35792830 DOI: 10.1111/tpj.15896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
Transposable elements (TEs) constitute a large proportion of genomes of multicellular eukaryotes, including flowering plants. TEs are normally maintained in a silenced state and their transpositions rarely occur. Hybridization between distant species has been regarded as a 'shock' that stimulates genome reorganization, including TE mobilization. However, whether crosses between genetically close parents that result in viable and fertile offspring can induce TE transpositions has remained unclear. Here, we investigated the activation of long terminal repeat (LTR) retrotransposons in three Lotus japonicus recombinant inbred line (RIL) populations. We found that at least six LTR retrotransposon families were activated and transposed in 78% of the RILs investigated. LORE1a, one of the transposed LTR retrotransposons, showed transgenerational epigenetic activation, indicating the long-term effects of epigenetic instability induced by hybridization. Our study highlights TE activation as an unexpectedly common event in plant reproduction.
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Affiliation(s)
- Eigo Fukai
- Graduate School of Science and Technology, Niigata University, Ikarashi-ninocho, 950-2181, Niigata, Japan
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2, Oowashi, Tsukuba, Ibaraki, 305-8634, Japan
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus, Denmark
- Plant Cytogenetics, Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
- Department of Technology Development, Kazusa DNA Research Institute, Kisarazu, Chiba, 292-0818, Japan
| | - Manabu Yoshikawa
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2, Oowashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Niraj Shah
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus, Denmark
| | - Niels Sandal
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus, Denmark
| | - Akio Miyao
- Institute of Crop Science, National Agriculture and Food Research Organization, 2-1-2, Kannondai, Tsukuba, Ibaraki, 305-8518, Japan
| | - Seijiro Ono
- Plant Cytogenetics, Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan
| | - Hideki Hirakawa
- Department of Technology Development, Kazusa DNA Research Institute, Kisarazu, Chiba, 292-0818, Japan
| | - Turgut Yigit Akyol
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus, Denmark
| | - Yosuke Umehara
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2, Oowashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Ken-Ichi Nonomura
- Department of Technology Development, Kazusa DNA Research Institute, Kisarazu, Chiba, 292-0818, Japan
| | - Jens Stougaard
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus, Denmark
| | - Hirohiko Hirochika
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2, Oowashi, Tsukuba, Ibaraki, 305-8634, Japan
| | - Makoto Hayashi
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 1-2, Oowashi, Tsukuba, Ibaraki, 305-8634, Japan
- Center for Sustainable Resource Science, RIKEN, Yokohama, Kanagawa, 230-0045, Japan
| | - Shusei Sato
- Department of Technology Development, Kazusa DNA Research Institute, Kisarazu, Chiba, 292-0818, Japan
- Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai, Miyagi, 980-8577, Japan
| | | | - Keiichi Okazaki
- Graduate School of Science and Technology, Niigata University, Ikarashi-ninocho, 950-2181, Niigata, Japan
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7
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Eriksson MC, Mandáková T, McCann J, Temsch EM, Chase MW, Hedrén M, Weiss-Schneeweiss H, Paun O. Repeat Dynamics across Timescales: A Perspective from Sibling Allotetraploid Marsh Orchids (Dactylorhiza majalis s.l.). Mol Biol Evol 2022; 39:msac167. [PMID: 35904928 PMCID: PMC9366187 DOI: 10.1093/molbev/msac167] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
To provide insights into the fate of transposable elements (TEs) across timescales in a post-polyploidization context, we comparatively investigate five sibling Dactylorhiza allotetraploids (Orchidaceae) formed independently and sequentially between 500 and 100K generations ago by unidirectional hybridization between diploids D. fuchsii and D. incarnata. Our results first reveal that the paternal D. incarnata genome shows a marked increased content of LTR retrotransposons compared to the maternal species, reflected in its larger genome size and consistent with a previously hypothesized bottleneck. With regard to the allopolyploids, in the youngest D. purpurella both genome size and TE composition appear to be largely additive with respect to parents, whereas for polyploids of intermediate ages we uncover rampant genome expansion on a magnitude of multiple entire genomes of some plants such as Arabidopsis. The oldest allopolyploids in the series are not larger than the intermediate ones. A putative tandem repeat, potentially derived from a non-autonomous miniature inverted-repeat TE (MITE) drives much of the genome dynamics in the allopolyploids. The highly dynamic MITE-like element is found in higher proportions in the maternal diploid, D. fuchsii, but is observed to increase in copy number in both subgenomes of the allopolyploids. Altogether, the fate of repeats appears strongly regulated and therefore predictable across multiple independent allopolyploidization events in this system. Apart from the MITE-like element, we consistently document a mild genomic shock following the allopolyploidizations investigated here, which may be linked to their relatively large genome sizes, possibly associated with strong selection against further genome expansions.
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Affiliation(s)
- Mimmi C Eriksson
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
- Vienna Graduate School of Population Genetics, Veterinärplatz 1, A-1210 Vienna, Austria
| | - Terezie Mandáková
- Plant Cytogenomics Research Group, CEITEC−Central−European Institute of Technology, Masaryk University, Brno 62500, Czech Republic
- Central European Institute of Technology, Masaryk University, Brno 62500, Czech Republic
- Institute of Experimental Biology, Faculty of Science, Masaryk University, Brno 62500, Czech Republic
| | - Jamie McCann
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
| | - Eva M Temsch
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
| | - Mark W Chase
- Royal Botanic Gardens Kew, London TW9 3AE, United Kingdom
- Department of Environment and Agriculture, Curtin University, Perth, Western Australia, Australia
| | - Mikael Hedrén
- Department of Biology, University of Lund, Sölvegatan 37, SE-223 62 Lund, Sweden
| | - Hanna Weiss-Schneeweiss
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
| | - Ovidiu Paun
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
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8
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Specificities and Dynamics of Transposable Elements in Land Plants. BIOLOGY 2022; 11:biology11040488. [PMID: 35453688 PMCID: PMC9033089 DOI: 10.3390/biology11040488] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 03/10/2022] [Accepted: 03/18/2022] [Indexed: 01/27/2023]
Abstract
Simple Summary Transposable elements are dynamic components of plant genomes, and display a high diversity of lineages and distribution as the result of evolutionary driving forces and overlapping mechanisms of genetic and epigenetic regulation. They are now regarded as main contributors for genome evolution and function, and important regulators of endogenous gene expression. In this review, we survey recent progress and current challenges in the identification and classification of transposon lineages in complex plant genomes, highlighting the molecular specificities that may explain the expansion and diversification of mobile genetic elements in land plants. Abstract Transposable elements (TEs) are important components of most plant genomes. These mobile repetitive sequences are highly diverse in terms of abundance, structure, transposition mechanisms, activity and insertion specificities across plant species. This review will survey the different mechanisms that may explain the variability of TE patterns in land plants, highlighting the tight connection between TE dynamics and host genome specificities, and their co-evolution to face and adapt to a changing environment. We present the current TE classification in land plants, and describe the different levels of genetic and epigenetic controls originating from the plant, the TE itself, or external environmental factors. Such overlapping mechanisms of TE regulation might be responsible for the high diversity and dynamics of plant TEs observed in nature.
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9
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Blasio F, Prieto P, Pradillo M, Naranjo T. Genomic and Meiotic Changes Accompanying Polyploidization. PLANTS (BASEL, SWITZERLAND) 2022; 11:125. [PMID: 35009128 PMCID: PMC8747196 DOI: 10.3390/plants11010125] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/24/2021] [Accepted: 12/29/2021] [Indexed: 05/04/2023]
Abstract
Hybridization and polyploidy have been considered as significant evolutionary forces in adaptation and speciation, especially among plants. Interspecific gene flow generates novel genetic variants adaptable to different environments, but it is also a gene introgression mechanism in crops to increase their agronomical yield. An estimate of 9% of interspecific hybridization has been reported although the frequency varies among taxa. Homoploid hybrid speciation is rare compared to allopolyploidy. Chromosome doubling after hybridization is the result of cellular defects produced mainly during meiosis. Unreduced gametes, which are formed at an average frequency of 2.52% across species, are the result of altered spindle organization or orientation, disturbed kinetochore functioning, abnormal cytokinesis, or loss of any meiotic division. Meiotic changes and their genetic basis, leading to the cytological diploidization of allopolyploids, are just beginning to be understood especially in wheat. However, the nature and mode of action of homoeologous recombination suppressor genes are poorly understood in other allopolyploids. The merger of two independent genomes causes a deep modification of their architecture, gene expression, and molecular interactions leading to the phenotype. We provide an overview of genomic changes and transcriptomic modifications that particularly occur at the early stages of allopolyploid formation.
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Affiliation(s)
- Francesco Blasio
- Departamento de Genética, Fisiología y Microbiología, Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain; (F.B.); (M.P.)
| | - Pilar Prieto
- Plant Breeding Department, Institute for Sustainable Agriculture, Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC), Alameda del Obispo s/n, Apartado 4048, 14080 Cordova, Spain;
| | - Mónica Pradillo
- Departamento de Genética, Fisiología y Microbiología, Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain; (F.B.); (M.P.)
| | - Tomás Naranjo
- Departamento de Genética, Fisiología y Microbiología, Facultad de Biología, Universidad Complutense de Madrid, 28040 Madrid, Spain; (F.B.); (M.P.)
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10
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Gantuz M, Morales A, Bertoldi MV, Ibañez VN, Duarte PF, Marfil CF, Masuelli RW. Hybridization and polyploidization effects on LTR-retrotransposon activation in potato genome. JOURNAL OF PLANT RESEARCH 2022; 135:81-92. [PMID: 34674075 DOI: 10.1007/s10265-021-01354-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 10/13/2021] [Indexed: 06/13/2023]
Abstract
Hybridization and polyploidization are major forces in plant evolution and potatoes are not an exception. It is proposed that the proliferation of Long Terminal Repeat-retrotransposons (LTR-RT) is related to genome reorganization caused by hybridization and/or polyploidization. The main purpose of the present work was to evaluate the effect of interspecific hybridization and polyploidization on the activation of LTR-RT. We evaluated the proliferation of putative active LTR-RT in a diploid hybrid between the cultivated potato Solanum tuberosum and the wild diploid potato species S. kurtzianum, allotetraploid lines derived from this interspecific hybrid and S. kurtzianum autotetraploid lines (ktz-autotetraploid) using the S-SAP (sequence-specific amplified polymorphism) technique and normalized copy number determination by qPCR. Twenty-nine LTR-RT copies were activated in the hybrid and present in the allotetraploid lines. Major LTR-RT activity was detected in Copia-27, Copia-12, Copia-14 and, Gypsy-22. According to our results, LTR-RT copies were activated principally in the hybrid, there was no activation in allotetraploid lines and only one copy was activated in the autotetraploid.
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Affiliation(s)
- Magdalena Gantuz
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina.
| | - Andrés Morales
- Instituto Nacional de Tecnología Agropecuaria (INTA), Luján de Cuyo, Mendoza, Argentina
| | - María Victoria Bertoldi
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina
| | - Verónica Noé Ibañez
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina
| | - Paola Fernanda Duarte
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina
| | - Carlos Federico Marfil
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina
| | - Ricardo Williams Masuelli
- Facultad de Ciencias Agrarias, Instituto de Biología Agrícola de Mendoza, Consejo Nacional de Investigaciones Científicas y Técnicas (IBAM-CONICET), Universidad Nacional de Cuyo, A. Brown 500 (M5528AHB) Chacras de Coria, Mendoza, Argentina.
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11
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Beric A, Mabry ME, Harkess AE, Brose J, Schranz ME, Conant GC, Edger PP, Meyers BC, Pires JC. Comparative phylogenetics of repetitive elements in a diverse order of flowering plants (Brassicales). G3 (BETHESDA, MD.) 2021; 11:jkab140. [PMID: 33993297 PMCID: PMC8495927 DOI: 10.1093/g3journal/jkab140] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2020] [Accepted: 04/10/2021] [Indexed: 11/14/2022]
Abstract
Genome sizes of plants have long piqued the interest of researchers due to the vast differences among organisms. However, the mechanisms that drive size differences have yet to be fully understood. Two important contributing factors to genome size are expansions of repetitive elements, such as transposable elements (TEs), and whole-genome duplications (WGD). Although studies have found correlations between genome size and both TE abundance and polyploidy, these studies typically test for these patterns within a genus or species. The plant order Brassicales provides an excellent system to further test if genome size evolution patterns are consistent across larger time scales, as there are numerous WGDs. This order is also home to one of the smallest plant genomes, Arabidopsis thaliana-chosen as the model plant system for this reason-as well as to species with very large genomes. With new methods that allow for TE characterization from low-coverage genome shotgun data and 71 taxa across the Brassicales, we confirm the correlation between genome size and TE content, however, we are unable to reconstruct phylogenetic relationships and do not detect any shift in TE abundance associated with WGD.
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Affiliation(s)
- Aleksandra Beric
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Makenzie E Mabry
- Division of Biological Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
| | - Alex E Harkess
- Department of Crop, Soil, and Environmental Sciences, Auburn University, Auburn, AL 36849, USA
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Julia Brose
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
| | - M Eric Schranz
- Biosystematics Group, Wageningen University, Wageningen 6700 AA, The Netherlands
| | - Gavin C Conant
- Bioinformatics Research Center, Program in Genetics and Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Patrick P Edger
- Department of Horticulture, Michigan State University, East Lansing, MI 48824, USA
- Department of Ecology, Evolutionary Biology and Behavior, Michigan State University, East Lansing, MI 48824, USA
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA
| | - J Chris Pires
- Division of Biological Sciences and Bond Life Sciences Center, University of Missouri, Columbia, MO 65211, USA
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12
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Zagorski D, Hartmann M, Bertrand YJK, Paštová L, Slavíková R, Josefiová J, Fehrer J. Characterization and Dynamics of Repeatomes in Closely Related Species of Hieracium (Asteraceae) and Their Synthetic and Apomictic Hybrids. FRONTIERS IN PLANT SCIENCE 2020; 11:591053. [PMID: 33224172 PMCID: PMC7667050 DOI: 10.3389/fpls.2020.591053] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/09/2020] [Indexed: 05/05/2023]
Abstract
The repetitive content of the plant genome (repeatome) often represents its largest fraction and is frequently correlated with its size. Transposable elements (TEs), the main component of the repeatome, are an important driver in the genome diversification due to their fast-evolving nature. Hybridization and polyploidization events are hypothesized to induce massive bursts of TEs resulting, among other effects, in an increase of copy number and genome size. Little is known about the repeatome dynamics following hybridization and polyploidization in plants that reproduce by apomixis (asexual reproduction via seeds). To address this, we analyzed the repeatomes of two diploid parental species, Hieracium intybaceum and H. prenanthoides (sexual), their diploid F1 synthetic and their natural triploid hybrids (H. pallidiflorum and H. picroides, apomictic). Using low-coverage next-generation sequencing (NGS) and a graph-based clustering approach, we detected high overall similarity across all major repeatome categories between the parental species, despite their large phylogenetic distance. Medium and highly abundant repetitive elements comprise ∼70% of Hieracium genomes; most prevalent were Ty3/Gypsy chromovirus Tekay and Ty1/Copia Maximus-SIRE elements. No TE bursts were detected, neither in synthetic nor in natural hybrids, as TE abundance generally followed theoretical expectations based on parental genome dosage. Slight over- and under-representation of TE cluster abundances reflected individual differences in genome size. However, in comparative analyses, apomicts displayed an overabundance of pararetrovirus clusters not observed in synthetic hybrids. Substantial deviations were detected in rDNAs and satellite repeats, but these patterns were sample specific. rDNA and satellite repeats (three of them were newly developed as cytogenetic markers) were localized on chromosomes by fluorescence in situ hybridization (FISH). In a few cases, low-abundant repeats (5S rDNA and certain satellites) showed some discrepancy between NGS data and FISH results, which is due partly to the bias of low-coverage sequencing and partly to low amounts of the satellite repeats or their sequence divergence. Overall, satellite DNA (including rDNA) was markedly affected by hybridization, but independent of the ploidy or reproductive mode of the progeny, whereas bursts of TEs did not play an important role in the evolutionary history of Hieracium.
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Nieto Feliner G, Casacuberta J, Wendel JF. Genomics of Evolutionary Novelty in Hybrids and Polyploids. Front Genet 2020; 11:792. [PMID: 32849797 PMCID: PMC7399645 DOI: 10.3389/fgene.2020.00792] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 07/03/2020] [Indexed: 12/15/2022] Open
Abstract
It has long been recognized that hybridization and polyploidy are prominent processes in plant evolution. Although classically recognized as significant in speciation and adaptation, recognition of the importance of interspecific gene flow has dramatically increased during the genomics era, concomitant with an unending flood of empirical examples, with or without genome doubling. Interspecific gene flow is thus increasingly thought to lead to evolutionary innovation and diversification, via adaptive introgression, homoploid hybrid speciation and allopolyploid speciation. Less well understood, however, are the suite of genetic and genomic mechanisms set in motion by the merger of differentiated genomes, and the temporal scale over which recombinational complexity mediated by gene flow might be expressed and exposed to natural selection. We focus on these issues here, considering the types of molecular genetic and genomic processes that might be set in motion by the saltational event of genome merger between two diverged species, either with or without genome doubling, and how these various processes can contribute to novel phenotypes. Genetic mechanisms include the infusion of new alleles and the genesis of novel structural variation including translocations and inversions, homoeologous exchanges, transposable element mobilization and novel insertional effects, presence-absence variation and copy number variation. Polyploidy generates massive transcriptomic and regulatory alteration, presumably set in motion by disrupted stoichiometries of regulatory factors, small RNAs and other genome interactions that cascade from single-gene expression change up through entire networks of transformed regulatory modules. We highlight both these novel combinatorial possibilities and the range of temporal scales over which such complexity might be generated, and thus exposed to natural selection and drift.
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Affiliation(s)
- Gonzalo Nieto Feliner
- Department of Biodiversity and Conservation, Real Jardín Botánico, CSIC, Madrid, Spain
| | - Josep Casacuberta
- Center for Research in Agricultural Genomics, CRAG (CSIC-IRTA-UAB-UB), Barcelona, Spain
| | - Jonathan F. Wendel
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States
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14
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Li M, Wang R, Wu X, Wang J. Homoeolog expression bias and expression level dominance (ELD) in four tissues of natural allotetraploid Brassica napus. BMC Genomics 2020; 21:330. [PMID: 32349676 PMCID: PMC7191788 DOI: 10.1186/s12864-020-6747-1] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 04/21/2020] [Indexed: 01/01/2023] Open
Abstract
Background Allopolyploidy is widespread in angiosperms, and they can coordinate two or more different genomes through genetic and epigenetic modifications to exhibit stronger vigor and adaptability. To explore the changes in homologous gene expression patterns in the natural allotetraploid Brassica napus (AnAnCnCn) relative to its two diploid progenitors, B. rapa (ArAr) and B. oleracea (CoCo), after approximately 7500 years of domestication, the global gene pair expression patterns in four major tissues (stems, leaves, flowers and siliques) of these three species were analyzed using an RNA sequencing approach. Results The results showed that the ‘transcriptomic shock’ phenomenon was alleviated in natural B. napus after approximately 7500 years of natural domestication, and most differentially expressed genes (DEGs) in B. napus were downregulated relative to those in its two diploid progenitors. The KEGG analysis indicated that three pathways related to photosynthesis were enriched in both comparison groups (AnAnCnCn vs ArAr and AnAnCnCn vs CoCo), and these pathways were all downregulated in four tissues of B. napus. In addition, homoeolog expression bias and expression level dominance (ELD) in B. napus were thoroughly studied through analysis of expression levels of 27,609 B. rapa-B. oleracea orthologous gene pairs. The overwhelming majority of gene pairs (an average of 86.7%) in B. napus maintained their expression pattern in two diploid progenitors, and approximately 78.1% of the gene pairs showed expression bias with a preference toward the A subgenome. Overall, an average of 48, 29.7 and 22.3% homologous gene pairs exhibited additive expression, ELD and transgressive expression in B. napus, respectively. The ELD bias varies from tissue to tissue; specifically, more gene pairs in stems and siliques showed ELD-A, whereas the opposite was observed in leaves and flowers. More transgressive upregulation, rather than downregulation, was observed in gene pairs of B. napus. Conclusions In general, these results may provide a comprehensive understanding of the changes in homologous gene expression patterns in natural B. napus after approximately 7500 years of evolution and domestication and may enhance our understanding of allopolyploidy.
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Affiliation(s)
- Mengdi Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Ruihua Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Xiaoming Wu
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of CAAS, Wuhan, 430062, China
| | - Jianbo Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China.
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15
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Xie T, Zeng L, Chen X, Rong H, Wu J, Batley J, Jiang J, Wang Y. Genome-Wide Analysis of the Lateral Organ Boundaries Domain Gene Family in Brassica Napus. Genes (Basel) 2020; 11:genes11030280. [PMID: 32155746 PMCID: PMC7140802 DOI: 10.3390/genes11030280] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 02/08/2023] Open
Abstract
The plant specific LATERAL ORGAN BOUNDARIES (LOB)-domain (LBD) proteins belong to a family of transcription factors that play important roles in plant growth and development, as well as in responses to various stresses. However, a comprehensive study of LBDs in Brassica napus has not yet been reported. In the present study, 126 BnLBD genes were identified in B. napus genome using bioinformatics analyses. The 126 BnLBDs were phylogenetically classified into two groups and nine subgroups. Evolutionary analysis indicated that whole genome duplication (WGD) and segmental duplication played important roles in the expansion of the BnLBD gene family. On the basis of the RNA-seq analyses, we identified BnLBD genes with tissue or developmental specific expression patterns. Through cis-acting element analysis and hormone treatment, we identified 19 BnLBD genes with putative functions in plant response to abscisic acid (ABA) treatment. This study provides a comprehensive understanding on the origin and evolutionary history of LBDs in B. napus, and will be helpful in further functional characterisation of BnLBDs.
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Affiliation(s)
- Tao Xie
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou 225009, China; (T.X.); (L.Z.); (X.C.); (H.R.); (J.W.); (Y.W.)
| | - Lei Zeng
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou 225009, China; (T.X.); (L.Z.); (X.C.); (H.R.); (J.W.); (Y.W.)
| | - Xin Chen
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou 225009, China; (T.X.); (L.Z.); (X.C.); (H.R.); (J.W.); (Y.W.)
| | - Hao Rong
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou 225009, China; (T.X.); (L.Z.); (X.C.); (H.R.); (J.W.); (Y.W.)
| | - Jingjing Wu
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou 225009, China; (T.X.); (L.Z.); (X.C.); (H.R.); (J.W.); (Y.W.)
| | - Jacqueline Batley
- School of Biological Sciences, University of Western Australia, Perth, WA 6009, Australia;
| | - Jinjin Jiang
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou 225009, China; (T.X.); (L.Z.); (X.C.); (H.R.); (J.W.); (Y.W.)
- Correspondence: ; Tel.: +86-514-87997303
| | - Youping Wang
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou 225009, China; (T.X.); (L.Z.); (X.C.); (H.R.); (J.W.); (Y.W.)
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Cavé-Radet A, Giraud D, Lima O, El Amrani A, Aïnouche M, Salmon A. Evolution of small RNA expression following hybridization and allopolyploidization: insights from Spartina species (Poaceae, Chloridoideae). PLANT MOLECULAR BIOLOGY 2020; 102:55-72. [PMID: 31748889 DOI: 10.1007/s11103-019-00931-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Accepted: 11/09/2019] [Indexed: 06/10/2023]
Abstract
Differential expression of mi-RNAs targeting developmental processes and progressive downregulation of repeat-associated siRNAs following genome merger and genome duplication in the context of allopolyploid speciation in Spartina. The role of small RNAs on gene expression regulation and genome stability is arousing increased interest and is being explored in various plant systems. In spite of prominence of reticulate evolution and polyploidy that affects the evolutionary history of all plant lineages, very few studies analysed RNAi mechanisms with this respect. Here, we explored small RNAs diversity and expression in the context of recent allopolyploid speciation, using the Spartina system, which offers a unique opportunity to explore the immediate changes following hybridization and genome duplication. Small RNA-Seq analyses were conducted on hexaploid parental species (S. alterniflora and S. maritima), their F1 hybrid S. x townsendii, and the neoallododecaploid S. anglica. We identified 594 miRNAs, 2197 miRNA-target genes, and 3730 repeat-associated siRNAs (mostly targeting Class I/Copia-Ivana- Copia-SIRE and LINEs elements). For both mi- and ra-siRNAs, we detected differential expression patterns following genome merger and genome duplication. These misregulations include non-additive expression of miRNAs in the F1 hybrid and additional changes in the allopolyploid targeting developmental processes. Expression of repeat-associated siRNAs indicates a strengthen of transposable element repression during the allopolyploidization process. Altogether, these results confirm the central role small RNAs play in shaping regulatory changes in naturally formed recent allopolyploids.
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Affiliation(s)
- Armand Cavé-Radet
- Université de Rennes 1, Centre National de la Recherche Scientifique, UMR CNRS 6553 ECOBIO, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Delphine Giraud
- Université de Rennes 1, Centre National de la Recherche Scientifique, UMR CNRS 6553 ECOBIO, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Oscar Lima
- Université de Rennes 1, Centre National de la Recherche Scientifique, UMR CNRS 6553 ECOBIO, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Abdelhak El Amrani
- Université de Rennes 1, Centre National de la Recherche Scientifique, UMR CNRS 6553 ECOBIO, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Malika Aïnouche
- Université de Rennes 1, Centre National de la Recherche Scientifique, UMR CNRS 6553 ECOBIO, Campus de Beaulieu, 35042, Rennes Cedex, France
| | - Armel Salmon
- Université de Rennes 1, Centre National de la Recherche Scientifique, UMR CNRS 6553 ECOBIO, Campus de Beaulieu, 35042, Rennes Cedex, France.
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Divashuk MG, Karlov GI, Kroupin PY. Copy Number Variation of Transposable Elements in Thinopyrum intermedium and Its Diploid Relative Species. PLANTS (BASEL, SWITZERLAND) 2019; 9:E15. [PMID: 31877707 PMCID: PMC7020174 DOI: 10.3390/plants9010015] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/05/2019] [Accepted: 12/17/2019] [Indexed: 12/14/2022]
Abstract
Diploid and polyploid wild species of Triticeae have complex relationships, and the understanding of their evolution and speciation could help to increase the usability of them in wheat breeding as a source of genetic diversity. The diploid species Pseudoroegneria spicata (St), Thinopyrum bessarabicum (Jb), Dasypyrum villosum (V) derived from a hypothetical common ancestor are considered to be possible subgenome donors in hexaploid species Th. intermedium (JrJvsSt, where indices r, v, and s stand for the partial relation to the genomes of Secale, Dasypyrum, and Pseudoroegneria, respectively). We quantified 10 families of transposable elements (TEs) in P. spicata, Th. bessarabicum, D. villosum (per one genome), and Th. intermedium (per one average subgenome) using the quantitative real time PCR assay and compared their abundance within the studied genomes as well as between them. Sabrina was the most abundant among all studied elements in P. spicata, D. villosum, and Th. intermedium, and among Ty3/Gypsy elements in all studied species. Among Ty1/Copia elements, Angela-A and WIS-A showed the highest and close abundance with the exception of D. villosum, and comprised the majority of all studied elements in Th. bessarabicum. Sabrina, BAGY2, and Angela-A showed similar abundance among diploids and in Th. intermedium hexaploid; Latidu and Barbara demonstrated sharp differences between diploid genomes. The relationships between genomes of Triticeae species based on the studied TE abundance and the role of TEs in speciation and polyploidization in the light of the current phylogenetic models is discussed.
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Affiliation(s)
- Mikhail G. Divashuk
- Laboratory of Applied Genomics and Crop Breeding, All-Russia Research Institute of Agricultural Biotechnology, Moscow 127550, Russia; (M.G.D.)
- Centre for Molecular Biotechnology, Russian State Agrarian University-Timiryazev Agricultural Academy, Moscow 127550, Russia
| | - Gennady I. Karlov
- Laboratory of Applied Genomics and Crop Breeding, All-Russia Research Institute of Agricultural Biotechnology, Moscow 127550, Russia; (M.G.D.)
- Centre for Molecular Biotechnology, Russian State Agrarian University-Timiryazev Agricultural Academy, Moscow 127550, Russia
| | - Pavel Yu. Kroupin
- Laboratory of Applied Genomics and Crop Breeding, All-Russia Research Institute of Agricultural Biotechnology, Moscow 127550, Russia; (M.G.D.)
- Centre for Molecular Biotechnology, Russian State Agrarian University-Timiryazev Agricultural Academy, Moscow 127550, Russia
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Relaxed purifying selection in autopolyploids drives transposable element over-accumulation which provides variants for local adaptation. Nat Commun 2019; 10:5818. [PMID: 31862875 PMCID: PMC6925279 DOI: 10.1038/s41467-019-13730-0] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 11/21/2019] [Indexed: 11/28/2022] Open
Abstract
Polyploidization is frequently associated with increased transposable element (TE) content. However, what drives TE dynamics following whole genome duplication (WGD) and the evolutionary implications remain unclear. Here, we leverage whole-genome resequencing data available for ~300 individuals of Arabidopsis arenosa, a well characterized natural diploid-autotetraploid plant species, to address these questions. Based on 43,176 TE insertions we detect in these genomes, we demonstrate that relaxed purifying selection rather than transposition bursts is the main driver of TE over-accumulation after WGD. Furthermore, the increased pool of TE insertions in tetraploids is especially enriched within or near environmentally responsive genes. Notably, we show that the major flowering-time repressor gene FLC is disrupted by a TE insertion specifically in the rapid-cycling tetraploid lineage that colonized mainland railways. Together, our findings indicate that tetrasomy leads to an enhanced accumulation of genic TE insertions, some of which likely contribute to local adaptation. Why transposable elements (TEs) accumulate in polyploids and the evolutionary implications remain unclear. Here, the authors show that following whole genome duplication, relaxed purifying selection is the main driver of TE over-accumulation, which provides variants for rapid local adaptation.
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Usai G, Mascagni F, Vangelisti A, Giordani T, Ceccarelli M, Cavallini A, Natali L. Interspecific hybridisation and LTR-retrotransposon mobilisation-related structural variation in plants: A case study. Genomics 2019; 112:1611-1621. [PMID: 31605729 DOI: 10.1016/j.ygeno.2019.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 07/13/2019] [Accepted: 09/12/2019] [Indexed: 11/30/2022]
Abstract
The dynamics of long-terminal-repeat retrotransposons in two poplar species (Populus deltoides and P. nigra) and in an interspecific hybrid, recently synthesized, were investigated by analyzing the genomic abundance and transcription levels of a collection of 828 full-length retroelements identified in the genome sequence of P. trichocarpa, all occurring also in the genomes of P. deltoides and P. nigra. Overall, genomic abundance and transcription levels of many retrotransposons in the hybrid resulted higher or lower than expected by calculating the mean of the parental values. A bioinformatics procedure was established to ascertain the occurrence of the same retrotransposon loci in the three genotypes. The results indicated that retrotransposon abundance variations between the hybrid and the mean value of the parents were due to i) co-segregation of retrotransposon high- or low-abundant haplotypes; ii) new retroelement insertions; iii) retrotransposon loss. Concerning retrotransposon expression, this was generally low, with only 14/828 elements over- or under-expressed in the hybrid than expected by calculating the mean of the parents. It is concluded that interspecific hybridisation between the two poplar species determine quantitative variation and differential expression of some retrotransposons, with possible consequences for the genetic differentiation of the hybrid.
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Affiliation(s)
- Gabriele Usai
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Flavia Mascagni
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Alberto Vangelisti
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Tommaso Giordani
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy
| | - Marilena Ceccarelli
- Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Elce di sotto 8, 06123 Perugia, Italy
| | - Andrea Cavallini
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy.
| | - Lucia Natali
- Department of Agriculture, Food and Environment, University of Pisa, Via del Borghetto 80, I-56124 Pisa, Italy.
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20
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Martinez Palacios P, Jacquemot MP, Tapie M, Rousselet A, Diop M, Remoué C, Falque M, Lloyd A, Jenczewski E, Lassalle G, Chévre AM, Lelandais C, Crespi M, Brabant P, Joets J, Alix K. Assessing the Response of Small RNA Populations to Allopolyploidy Using Resynthesized Brassica napus Allotetraploids. Mol Biol Evol 2019; 36:709-726. [PMID: 30657939 PMCID: PMC6445299 DOI: 10.1093/molbev/msz007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Allopolyploidy, combining interspecific hybridization with whole genome duplication, has had significant impact on plant evolution. Its evolutionary success is related to the rapid and profound genome reorganizations that allow neoallopolyploids to form and adapt. Nevertheless, how neoallopolyploid genomes adapt to regulate their expression remains poorly understood. The hypothesis of a major role for small noncoding RNAs (sRNAs) in mediating the transcriptional response of neoallopolyploid genomes has progressively emerged. Generally, 21-nt sRNAs mediate posttranscriptional gene silencing by mRNA cleavage, whereas 24-nt sRNAs repress transcription (transcriptional gene silencing) through epigenetic modifications. Here, we characterize the global response of sRNAs to allopolyploidy in Brassica, using three independently resynthesized Brassica napus allotetraploids originating from crosses between diploid Brassica oleracea and Brassica rapa accessions, surveyed at two different generations in comparison with their diploid progenitors. Our results suggest an immediate but transient response of specific sRNA populations to allopolyploidy. These sRNA populations mainly target noncoding components of the genome but also target the transcriptional regulation of genes involved in response to stresses and in metabolism; this suggests a broad role in adapting to allopolyploidy. We finally identify the early accumulation of both 21- and 24-nt sRNAs involved in regulating the same targets, supporting a posttranscriptional gene silencing to transcriptional gene silencing shift at the first stages of the neoallopolyploid formation. We propose that reorganization of sRNA production is an early response to allopolyploidy in order to control the transcriptional reactivation of various noncoding elements and stress-related genes, thus ensuring genome stability during the first steps of neoallopolyploid formation.
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Affiliation(s)
- Paulina Martinez Palacios
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Marie-Pierre Jacquemot
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France.,Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Marion Tapie
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Agnès Rousselet
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Mamoudou Diop
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Carine Remoué
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Matthieu Falque
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Andrew Lloyd
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Eric Jenczewski
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Gilles Lassalle
- IGEPP, INRA, Agrocampus Ouest, Univ. Rennes I, Le Rheu, France.,ESE, INRA, Agrocampus Ouest, Rennes, France
| | | | - Christine Lelandais
- IPS2, Institute of Plant Sciences Paris-Saclay, CNRS, INRA, Universités Paris Diderot, Paris Sud and Evry, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Martin Crespi
- IPS2, Institute of Plant Sciences Paris-Saclay, CNRS, INRA, Universités Paris Diderot, Paris Sud and Evry, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Philippe Brabant
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Johann Joets
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
| | - Karine Alix
- GQE - Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif-sur-Yvette, France
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Rodionov AV, Amosova AV, Belyakov EA, Zhurbenko PM, Mikhailova YV, Punina EO, Shneyer VS, Loskutov IG, Muravenko OV. Genetic Consequences of Interspecific Hybridization, Its Role in Speciation and Phenotypic Diversity of Plants. RUSS J GENET+ 2019. [DOI: 10.1134/s1022795419030141] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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22
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Mhiri C, Parisod C, Daniel J, Petit M, Lim KY, Dorlhac de Borne F, Kovarik A, Leitch AR, Grandbastien MA. Parental transposable element loads influence their dynamics in young Nicotiana hybrids and allotetraploids. THE NEW PHYTOLOGIST 2019; 221:1619-1633. [PMID: 30220091 DOI: 10.1111/nph.15484] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Accepted: 09/06/2018] [Indexed: 05/29/2023]
Abstract
The genomic shock hypothesis suggests that allopolyploidy is associated with genome changes driven by transposable elements, as a response to imbalances between parental insertion loads. To explore this hypothesis, we compared three allotetraploids, Nicotiana arentsii, N. rustica and N. tabacum, which arose over comparable time frames from hybridisation between increasingly divergent diploid species. We used sequence-specific amplification polymorphism (SSAP) to compare the dynamics of six transposable elements in these allopolyploids, their diploid progenitors and in corresponding synthetic hybrids. We show that element-specific dynamics in young Nicotiana allopolyploids reflect their dynamics in diploid progenitors. Transposable element mobilisation is not concomitant with immediate genome merger, but occurs within the first generations of allopolyploid formation. In natural allopolyploids, such mobilisations correlate with imbalances in the repeat profile of the parental species, which increases with their genetic divergence. Other restructuring leading to locus loss is immediate, nonrandom and targeted at specific subgenomes, independently of cross orientation. The correlation between transposable element mobilisation in allopolyploids and quantitative imbalances in parental transposable element loads supports the genome shock hypothesis proposed by McClintock.
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Affiliation(s)
- Corinne Mhiri
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Christian Parisod
- Ecological Genomics, Institute of Plant Sciences, University of Bern, Bern, CH-3013, Switzerland
| | - Julien Daniel
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - Maud Petit
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
| | - K Yoong Lim
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | | | - Ales Kovarik
- Institute of Biophysics, Academy of Sciences of the Czech Republic, Brno, CZ-61265, Czech Republic
| | - Andrew R Leitch
- School of Biological and Chemical Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Marie-Angèle Grandbastien
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France
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23
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Shaping Plant Adaptability, Genome Structure and Gene Expression through Transposable Element Epigenetic Control: Focus on Methylation. AGRONOMY-BASEL 2018. [DOI: 10.3390/agronomy8090180] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
In plants, transposable elements (TEs) represent a large fraction of the genome, with potential to alter gene expression and produce genomic rearrangements. Epigenetic control of TEs is often used to stop unrestricted movement of TEs that would result in detrimental effects due to insertion in essential genes. The current review focuses on the effects of methylation on TEs and their genomic context, and how this type of epigenetic control affects plant adaptability when plants are faced with different stresses and changes. TEs mobilize in response to stress elicitors, including biotic and abiotic cues, but also developmental transitions and ‘genome shock’ events like polyploidization. These events transitionally lift TE repression, allowing TEs to move to new genomic locations. When TEs fall close to genes, silencing through methylation can spread to nearby genes, resulting in lower gene expression. The presence of TEs in gene promoter regions can also confer stress inducibility modulated through alternative methylation and demethylation of the TE. Bursts of transposition triggered by events of genomic shock can increase genome size and account for differences seen during polyploidization or species divergence. Finally, TEs have evolved several mechanisms to suppress their own repression, including the use of microRNAs to control genes that promote methylation. The interplay between silencing, transient TE activation, and purifying selection allows the genome to use TEs as a reservoir of potential beneficial modifications but also keeps TEs under control to stop uncontrolled detrimental transposition.
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Wu J, Lin L, Xu M, Chen P, Liu D, Sun Q, Ran L, Wang Y. Homoeolog expression bias and expression level dominance in resynthesized allopolyploid Brassica napus. BMC Genomics 2018; 19:586. [PMID: 30081834 PMCID: PMC6080508 DOI: 10.1186/s12864-018-4966-5] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 07/30/2018] [Indexed: 01/08/2023] Open
Abstract
Background Allopolyploids require rapid genetic and epigenetic modifications to reconcile two or more sets of divergent genomes. To better understand the fate of duplicate genes following genomic mergers and doubling during allopolyploid formation, in this study, we explored the global gene expression patterns in resynthesized allotetraploid Brassica napus (AACC) and its diploid parents B. rapa (AA) and B. oleracea (CC) using RNA sequencing of leaf transcriptomes. Results We found that allopolyploid B. napus formation was accompanied by extensive changes (approximately one-third of the expressed genes) in the parental gene expression patterns (‘transcriptome shock’). Interestingly, the majority (85%) of differentially expressed genes (DEGs) were downregulated in the allotetraploid. Moreover, the homoeolog expression bias (relative contribution of homoeologs to the transcriptome) and expression level dominance (total expression level of both homoeologs) were thoroughly investigated by monitoring the expression of 23,766 B. oleracea-B. rapa orthologous gene pairs. Approximately 36.5% of the expressed gene pairs displayed expression bias with a slight preference toward the A-genome. In addition, 39.6, 4.9 and 9.0% of the expressed gene pairs exhibited expression level dominance (ELD), additivity expression and transgressive expression, respectively. The genome-wide ELD was also biased toward the A-genome in the resynthesized B. napus. To explain the ELD phenomenon, we compared the individual homoeolog expression levels relative to those of the diploid parents and found that ELD in the direction of the higher-expression parent can be explained by the downregulation of homoeologs from the dominant parent or upregulation of homoeologs from the nondominant parent; however, ELD in the direction of the lower-expression parent can be explained only by the downregulation of the nondominant parent or both homoeologs. Furthermore, Gene Ontology (GO) enrichment analysis suggested that the alteration in the gene expression patterns could be a prominent cause of the phenotypic variation between the newly formed B. napus and its parental species. Conclusions Collectively, our data provide insight into the rapid repatterning of gene expression at the beginning of Brassica allopolyploidization and enhance our knowledge of allopolyploidization processes. Electronic supplementary material The online version of this article (10.1186/s12864-018-4966-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jian Wu
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Li Lin
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Meiling Xu
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Peipei Chen
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Dongxiao Liu
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Qinfu Sun
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Liping Ran
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China
| | - Youping Wang
- Jiangsu Provincial Key Laboratory of Crop Genetics and Physiology, Yangzhou University, Yangzhou, 225009, China.
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Samans B, Chalhoub B, Snowdon RJ. Surviving a Genome Collision: Genomic Signatures of Allopolyploidization in the Recent Crop Species Brassica napus. THE PLANT GENOME 2017; 10. [PMID: 29293818 DOI: 10.3835/plantgenome2017.02.0013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Polyploidization has played a major role in crop plant evolution, leading to advantageous traits that have been selected by humans. Here, we describe restructuring patterns in the genome of L., a recent allopolyploid species. Widespread segmental deletions, duplications, and homeologous chromosome exchanges were identified in diverse genome sequences from 32 natural and 20 synthetic accessions, indicating that homeologous exchanges are a major driver of postpolyploidization genome diversification. Breakpoints of genomic rearrangements are rich in microsatellite sequences that are known to interact with the meiotic recombination machinery. In both synthetic and natural , a subgenome bias was observed toward exchanges replacing larger chromosome segments from the C-subgenome by their smaller, homeologous A-subgenome segments, driving postpolyploidization genome size reduction. Selection in natural favored segmental deletions involving genes associated with immunity, reproduction, and adaptation. Deletions affecting mismatch repair system genes, which are assumed to control homeologous recombination, were also found to be under selection. Structural exchanges between homeologous subgenomes appear to be a major source of novel genetic diversity in de novo allopolyploids. Documenting the consequences of genomic collision by genomic resequencing gives insights into the adaptive processes accompanying allopolyploidization.
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Vicient CM, Casacuberta JM. Impact of transposable elements on polyploid plant genomes. ANNALS OF BOTANY 2017; 120:195-207. [PMID: 28854566 PMCID: PMC5737689 DOI: 10.1093/aob/mcx078] [Citation(s) in RCA: 143] [Impact Index Per Article: 20.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 05/23/2017] [Indexed: 05/18/2023]
Abstract
BACKGROUND The growing wealth of knowledge on whole-plant genome sequences is highlighting the key role of transposable elements (TEs) in plant evolution, as a driver of drastic changes in genome size and as a source of an important number of new coding and regulatory sequences. Together with polyploidization events, TEs should thus be considered the major players in evolution of plants. SCOPE This review outlines the major mechanisms by which TEs impact plant genome evolution and how polyploidy events can affect these impacts, and vice versa. These include direct effects on genes, by providing them with new coding or regulatory sequences, an effect on the epigenetic status of the chromatin close to genes, and more subtle effects by imposing diverse evolutionary constraints to different chromosomal regions. These effects are particularly relevant after polyploidization events. Polyploidization often induces bursts of transposition probably due to a relaxation in their epigenetic control, and, in the short term, this can increase the rate of gene mutations and changes in gene regulation due to the insertion of TEs next to or into genes. Over longer times, TE bursts may induce global changes in genome structure due to inter-element recombination including losses of large genome regions and chromosomal rearrangements that reduce the genome size and the chromosome number as part of a process called diploidization. CONCLUSIONS TEs play an essential role in genome and gene evolution, in particular after polyploidization events. Polyploidization can induce TE activity that may explain part of the new phenotypes observed. TEs may also play a role in the diploidization that follows polyploidization events. However, the extent to which TEs contribute to diploidization and fractionation bias remains unclear. Investigating the multiple factors controlling TE dynamics and the nature of ancient and recent polyploid genomes may shed light on these processes.
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Affiliation(s)
- Carlos M. Vicient
- Center for Research in Agricultural Genomics, CRAG (CSIC-IRTA-UAB-UB), Campus UAB, Cerdanyola del Vallès, 08193 Barcelona, Spain
- For correspondence. E-mail
| | - Josep M. Casacuberta
- Center for Research in Agricultural Genomics, CRAG (CSIC-IRTA-UAB-UB), Campus UAB, Cerdanyola del Vallès, 08193 Barcelona, Spain
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Jin X, Ren J, Nevo E, Yin X, Sun D, Peng J. Divergent Evolutionary Patterns of NAC Transcription Factors Are Associated with Diversification and Gene Duplications in Angiosperm. FRONTIERS IN PLANT SCIENCE 2017; 8:1156. [PMID: 28713414 PMCID: PMC5492850 DOI: 10.3389/fpls.2017.01156] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 06/15/2017] [Indexed: 05/20/2023]
Abstract
NAC (NAM/ATAF/CUC) proteins constitute one of the biggest plant-specific transcription factor (TF) families and have crucial roles in diverse developmental programs during plant growth. Phylogenetic analyses have revealed both conserved and lineage-specific NAC subfamilies, among which various origins and distinct features were observed. It is reasonable to hypothesize that there should be divergent evolutionary patterns of NAC TFs both between dicots and monocots, and among NAC subfamilies. In this study, we compared the gene duplication and loss, evolutionary rate, and selective pattern among non-lineage specific NAC subfamilies, as well as those between dicots and monocots, through genome-wide analyses of sequence and functional data in six dicot and five grass lineages. The number of genes gained in the dicot lineages was much larger than that in the grass lineages, while fewer gene losses were observed in the grass than that in the dicots. We revealed (1) uneven constitution of Clusters of Orthologous Groups (COGs) and contrasting birth/death rates among subfamilies, and (2) two distinct evolutionary scenarios of NAC TFs between dicots and grasses. Our results demonstrated that relaxed selection, resulting from concerted gene duplications, may have permitted substitutions responsible for functional divergence of NAC genes into new lineages. The underlying mechanism of distinct evolutionary fates of NAC TFs shed lights on how evolutionary divergence contributes to differences in establishing NAC gene subfamilies and thus impacts the distinct features between dicots and grasses.
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Affiliation(s)
- Xiaoli Jin
- Department of Agronomy and the Key Laboratory of Crop Germplasm Resource of Zhejiang Province, Zhejiang UniversityHangzhou, China
| | - Jing Ren
- Shandong Provincial Key Laboratory of Biophysics, Institute of Biophysics, Dezhou UniversityDezhou, China
| | - Eviatar Nevo
- Department of Evolutionary and Environmental Biology, Institute of Evolution, University of HaifaHaifa, Israel
| | - Xuegui Yin
- Department of Biotechnology, College of Agriculture, Guangdong Ocean UniversityZhanjiang, China
| | - Dongfa Sun
- Department of Agronomy, College of Plant Science and Technology, Huazhong Agricultural UniversityWuhan, China
| | - Junhua Peng
- Department of Biotechnology, College of Agriculture, Guangdong Ocean UniversityZhanjiang, China
- Life Science & Technology Center, and the State Key Lab of Crop Breeding Technology Innovation and Integration, China National Seed Group Co., Ltd.Wuhan, China
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Pelé A, Falque M, Trotoux G, Eber F, Nègre S, Gilet M, Huteau V, Lodé M, Jousseaume T, Dechaumet S, Morice J, Poncet C, Coriton O, Martin OC, Rousseau-Gueutin M, Chèvre AM. Amplifying recombination genome-wide and reshaping crossover landscapes in Brassicas. PLoS Genet 2017; 13:e1006794. [PMID: 28493942 PMCID: PMC5444851 DOI: 10.1371/journal.pgen.1006794] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Revised: 05/25/2017] [Accepted: 05/02/2017] [Indexed: 11/19/2022] Open
Abstract
Meiotic recombination by crossovers (COs) is tightly regulated, limiting its key role in producing genetic diversity. However, while COs are usually restricted in number and not homogenously distributed along chromosomes, we show here how to disrupt these rules in Brassica species by using allotriploid hybrids (AAC, 2n = 3x = 29), resulting from the cross between the allotetraploid rapeseed (B. napus, AACC, 2n = 4x = 38) and one of its diploid progenitors (B. rapa, AA, 2n = 2x = 20). We produced mapping populations from different genotypes of both diploid AA and triploid AAC hybrids, used as female and/or as male. Each population revealed nearly 3,000 COs that we studied with SNP markers well distributed along the A genome (on average 1 SNP per 1.25 Mbp). Compared to the case of diploids, allotriploid hybrids showed 1.7 to 3.4 times more overall COs depending on the sex of meiosis and the genetic background. Most surprisingly, we found that such a rise was always associated with (i) dramatic changes in the shape of recombination landscapes and (ii) a strong decrease of CO interference. Hybrids carrying an additional C genome exhibited COs all along the A chromosomes, even in the vicinity of centromeres that are deprived of COs in diploids as well as in most studied species. Moreover, in male allotriploid hybrids we found that Class I COs are mostly responsible for the changes of CO rates, landscapes and interference. These results offer the opportunity for geneticists and plant breeders to dramatically enhance the generation of diversity in Brassica species by disrupting the linkage drag coming from limits on number and distribution of COs.
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Affiliation(s)
- Alexandre Pelé
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - Matthieu Falque
- GQE-Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif sur Yvette, France
| | - Gwenn Trotoux
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - Frédérique Eber
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - Sylvie Nègre
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - Marie Gilet
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - Virginie Huteau
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - Maryse Lodé
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | | | - Sylvain Dechaumet
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - Jérôme Morice
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | | | - Olivier Coriton
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
| | - Olivier C. Martin
- GQE-Le Moulon, INRA, Université Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, Gif sur Yvette, France
| | | | - Anne-Marie Chèvre
- IGEPP, INRA, Agrocampus Ouest, Université de Rennes 1, Le Rheu, France
- * E-mail:
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Abstract
LTR retrotransposons are the most abundant group of transposable elements (TEs) in plants. These elements can fall inside or close to genes, and therefore influence their expression and evolution. This review aims to examine how LTR retrotransposons, especially Ty1-copia elements, mediate gene regulation and evolution. Various stimuli, including polyploidization and biotic and abiotic elicitors, result in the transcription and movement of these retrotransposons, and can facilitate adaptation. The presence of cis-regulatory motifs in the LTRs are central to their stress-mediated responses and are shared with host stress-responsive genes, showing a complex evolutionary history in which TEs provide new regulatory units to genes. The presence of retrotransposon remnants in genes that are necessary for normal gene function, demonstrates the importance of exaptation and co-option, and is also a consequence of the abundance of these elements in plant genomes. Furthermore, insertions of LTR retrotransposons in and around genes provide potential for alternative splicing, epigenetic control, transduction, duplication and recombination. These characteristics can become an active part of the evolution of gene families as in the case of resistance genes (R-genes). The character of TEs as exclusively selfish is now being re-evaluated. Since genome-wide reprogramming via TEs is a long evolutionary process, the changes we can examine are case-specific and their fitness advantage may not be evident until TE-derived motifs and domains have been completely co-opted and fixed. Nevertheless, the presence of LTR retrotransposons inside genes and as part of gene promoter regions is consistent with their roles as engines of plant genome evolution.
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Sochorová J, Coriton O, Kuderová A, Lunerová J, Chèvre AM, Kovařík A. Gene conversion events and variable degree of homogenization of rDNA loci in cultivars of Brassica napus. ANNALS OF BOTANY 2017; 119:13-26. [PMID: 27707747 PMCID: PMC5218374 DOI: 10.1093/aob/mcw187] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/12/2016] [Indexed: 05/20/2023]
Abstract
BACKGROUND AND AIMS Brassica napus (AACC, 2n = 38, oilseed rape) is a relatively recent allotetraploid species derived from the putative progenitor diploid species Brassica rapa (AA, 2n = 20) and Brassica oleracea (CC, 2n = 18). To determine the influence of intensive breeding conditions on the evolution of its genome, we analysed structure and copy number of rDNA in 21 cultivars of B. napus, representative of genetic diversity. METHODS We used next-generation sequencing genomic approaches, Southern blot hybridization, expression analysis and fluorescence in situ hybridization (FISH). Subgenome-specific sequences derived from rDNA intergenic spacers (IGS) were used as probes for identification of loci composition on chromosomes. KEY RESULTS Most B. napus cultivars (18/21, 86 %) had more A-genome than C-genome rDNA copies. Three cultivars analysed by FISH ('Darmor', 'Yudal' and 'Asparagus kale') harboured the same number (12 per diploid set) of loci. In B. napus 'Darmor', the A-genome-specific rDNA probe hybridized to all 12 rDNA loci (eight on the A-genome and four on the C-genome) while the C-genome-specific probe showed weak signals on the C-genome loci only. Deep sequencing revealed high homogeneity of arrays suggesting that the C-genome genes were largely overwritten by the A-genome variants in B. napus 'Darmor'. In contrast, B. napus 'Yudal' showed a lack of gene conversion evidenced by additive inheritance of progenitor rDNA variants and highly localized hybridization signals of subgenome-specific probes on chromosomes. Brassica napus 'Asparagus kale' showed an intermediate pattern to 'Darmor' and 'Yudal'. At the expression level, most cultivars (95 %) exhibited stable A-genome nucleolar dominance while one cultivar ('Norin 9') showed co-dominance. CONCLUSIONS The B. napus cultivars differ in the degree and direction of rDNA homogenization. The prevalent direction of gene conversion (towards the A-genome) correlates with the direction of expression dominance indicating that gene activity may be needed for interlocus gene conversion.
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Affiliation(s)
- Jana Sochorová
- Laboratory of Molecular Epigenetics, Institute of Biophysics, Královopolská 135, 61265 Brno, Czech Academy of Science, v.v.i., Czech Republic
| | - Olivier Coriton
- Institut National de la Recherche Agronomique (INRA), UMR 1349 IGEPP, BP 35327, F-35653 Le Rheu cedex, France
| | - Alena Kuderová
- Laboratory of Molecular Epigenetics, Institute of Biophysics, Královopolská 135, 61265 Brno, Czech Academy of Science, v.v.i., Czech Republic
| | - Jana Lunerová
- Laboratory of Molecular Epigenetics, Institute of Biophysics, Královopolská 135, 61265 Brno, Czech Academy of Science, v.v.i., Czech Republic
| | - Anne-Marie Chèvre
- Institut National de la Recherche Agronomique (INRA), UMR 1349 IGEPP, BP 35327, F-35653 Le Rheu cedex, France
| | - Aleš Kovařík
- Laboratory of Molecular Epigenetics, Institute of Biophysics, Královopolská 135, 61265 Brno, Czech Academy of Science, v.v.i., Czech Republic
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Fu Y, Xiao M, Yu H, Mason AS, Yin J, Li J, Zhang D, Fu D. Small RNA changes in synthetic Brassica napus. PLANTA 2016; 244:607-622. [PMID: 27107747 DOI: 10.1007/s00425-016-2529-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 04/09/2016] [Indexed: 06/05/2023]
Abstract
Small RNAs and microRNAs were found to vary extensively in synthetic Brassica napus and subsequent generations, accompanied by the activation of transposable elements in response to hybridization and polyploidization. Resynthesizing B. napus by hybridization and chromosome doubling provides an approach to create novel polyploids and increases the usable genetic variability in oilseed rape. Although many studies have shown that small RNAs (sRNAs) act as important factor during hybridization and polyploidization in plants, much less is known on how sRNAs change in synthetic B. napus, particularly in subsequent generations after formation. We performed high-throughput sequencing of sRNAs in S1-S4 generations of synthetic B. napus and in the homozygous B. oleracea and B. rapa parent lines. We found that the number of small RNAs (sRNAs) and microRNAs (miRNAs) doubled in synthetic B. napus relative to the parents. The proportions of common sRNAs detected varied from the S1 to S4 generations, suggesting sRNAs are unstable in synthetic B. napus. The majority of miRNAs (67.2 %) were non-additively expressed in the synthesized Brassica allotetraploid, and 33.3 % of miRNAs were novel in the resynthesized B. napus. The percentage of miRNAs derived from transposable elements (TEs) also increased, indicating transposon activation and increased transposon-associated miRNA production in response to hybridization and polyploidization. The number of target genes for each miRNA in the synthesized Brassica allotetraploid was doubled relative to the parents, enhancing the complexity of gene expression regulation. The potential roles of miRNAs and their targets are discussed. Our data demonstrate generational changes in sRNAs and miRNAs in synthesized B. napus.
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Affiliation(s)
- Ying Fu
- Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Meili Xiao
- Engineering Research Center of South Upland Agriculture of Ministry of Education, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Agronomy College, Jiangxi Agricultural University, Nanchang, 330045, China
| | - Huasheng Yu
- Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, 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
| | - Jiaming Yin
- Engineering Research Center of South Upland Agriculture of Ministry of Education, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
| | - Jiana Li
- Engineering Research Center of South Upland Agriculture of Ministry of Education, College of Agronomy and Biotechnology, Southwest University, Chongqing, China
| | - Dongqing Zhang
- Institute of Crop and Nuclear Technology Utilization, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Donghui Fu
- Key Laboratory of Crop Physiology, Ecology and Genetic Breeding, Ministry of Education, Agronomy College, Jiangxi Agricultural University, Nanchang, 330045, China.
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Soltis DE, Visger CJ, Marchant DB, Soltis PS. Polyploidy: Pitfalls and paths to a paradigm. AMERICAN JOURNAL OF BOTANY 2016; 103:1146-66. [PMID: 27234228 DOI: 10.3732/ajb.1500501] [Citation(s) in RCA: 164] [Impact Index Per Article: 20.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2015] [Accepted: 02/25/2016] [Indexed: 05/22/2023]
Abstract
Investigators have long searched for a polyploidy paradigm-rules or principles that might be common following polyploidization (whole-genome duplication, WGD). Here we attempt to integrate what is known across the more thoroughly investigated polyploid systems on topics ranging from genetics to ecology. We found that while certain rules may govern gene retention and loss, systems vary in the prevalence of gene silencing vs. homeolog loss, chromosomal change, the presence of a dominant genome (in allopolyploids), and the relative importance of hybridization vs. genome doubling per se. In some lineages, aspects of polyploidization are repeated across multiple origins, but in other species multiple origins behave more stochastically in terms of genetic and phenotypic change. Our investigation also reveals that the path to synthesis is hindered by numerous gaps in our knowledge of even the best-known systems. Particularly concerning is the absence of linkage between genotype and phenotype. Moreover, most recent studies have focused on the genetic and genomic attributes of polyploidy, but rarely is there an ecological or physiological context. To promote a path to a polyploidy paradigm (or paradigms), we propose a major community goal over the next 10-20 yr to fill the gaps in our knowledge of well-studied polyploids. Before a meaningful synthesis is possible, more complete data sets are needed for comparison-systems that include comparable genetic, genomic, chromosomal, proteomic, as well as morphological, physiological, and ecological data. Also needed are more natural evolutionary model systems, as most of what we know about polyploidy continues to come from a few crop and genetic models, systems that often lack the ecological context inherent in natural systems and necessary for understanding the drivers of biodiversity.
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Affiliation(s)
- Douglas E Soltis
- Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611 USA Department of Biology, University of Florida, Gainesville, Florida 32611 USA Genetics Institute, University of Florida, Gainesville, Florida 32608 USA
| | - Clayton J Visger
- Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611 USA Department of Biology, University of Florida, Gainesville, Florida 32611 USA
| | - D Blaine Marchant
- Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611 USA Department of Biology, University of Florida, Gainesville, Florida 32611 USA
| | - Pamela S Soltis
- Florida Museum of Natural History, University of Florida, Gainesville, Florida 32611 USA Genetics Institute, University of Florida, Gainesville, Florida 32608 USA
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Cai G, Yang Q, Yi B, Fan C, Edwards D, Batley J, Zhou Y. A complex recombination pattern in the genome of allotetraploid Brassica napus as revealed by a high-density genetic map. PLoS One 2014; 9:e109910. [PMID: 25356735 PMCID: PMC4214627 DOI: 10.1371/journal.pone.0109910] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2014] [Accepted: 09/13/2014] [Indexed: 12/29/2022] Open
Abstract
Polyploidy plays a crucial role in plant evolution. Brassica napus (2n = 38, AACC), the most important oil crop in the Brassica genus, is an allotetraploid that originated through natural doubling of chromosomes after the hybridization of its progenitor species, B. rapa (2n = 20, AA) and B. oleracea (2n = 18, CC). A better understanding of the evolutionary relationship between B. napus and B. rapa, B. oleracea, as well as Arabidopsis, which has a common ancestor with these three species, will provide valuable information about the generation and evolution of allopolyploidy. Based on a high-density genetic map with single nucleotide polymorphism (SNP) and simple sequence repeat (SSR) markers, we performed a comparative genomic analysis of B. napus with Arabidopsis and its progenitor species B. rapa and B. oleracea. Based on the collinear relationship of B. rapa and B. oleracea in the B. napus genetic map, the B. napus genome was found to consist of 70.1% of the skeleton components of the chromosomes of B. rapa and B. oleracea, with 17.7% of sequences derived from reciprocal translocation between homoeologous chromosomes between the A- and C-genome and 3.6% of sequences derived from reciprocal translocation between non-homologous chromosomes at both intra- and inter-genomic levels. The current study thus provides insights into the formation and evolution of the allotetraploid B. napus genome, which will allow for more accurate transfer of genomic information from B. rapa, B. oleracea and Arabidopsis to B. napus.
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Affiliation(s)
- Guangqin Cai
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Rapeseed Genetics and Breeding of Agriculture Ministry of China, Huazhong Agricultural University, Wuhan, China
| | - Qingyong Yang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Bin Yi
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - Chuchuan Fan
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
| | - David Edwards
- School of Agriculture and Food Sciences, University of Queensland, St Lucia, Queensland, Australia
| | - Jacqueline Batley
- School of Agriculture and Food Sciences, University of Queensland, St Lucia, Queensland, Australia
| | - Yongming Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Rapeseed Genetics and Breeding of Agriculture Ministry of China, Huazhong Agricultural University, Wuhan, China
- * E-mail:
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Shen Y, Zhang Y, Zou J, Meng J, Wang J. Comparative proteomic study on Brassica hexaploid and its parents provides new insights into the effects of polyploidization. J Proteomics 2014; 112:274-84. [PMID: 25463267 DOI: 10.1016/j.jprot.2014.10.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 09/15/2014] [Accepted: 10/10/2014] [Indexed: 12/16/2022]
Abstract
UNLABELLED Polyploidy has played an important role in promoting plant evolution through genomic merging and doubling. Although genomic and transcriptomic changes have been observed in polyploids, the effects of polyploidization on proteomic divergence are poorly understood. In this study, we reported quantitative analysis of proteomic changes in leaves of Brassica hexaploid and its parents using isobaric tags for relative and absolute quantitation (iTRAQ) coupled with mass spectrometry. A total of 2044 reproducible proteins were quantified by at least two unique peptides. We detected 452 proteins differentially expressed between Brassica hexaploid and its parents, and 100 proteins were non-additively expressed in Brassica hexaploid, which suggested a trend of non-additive protein regulation following genomic merger and doubling. Functional categories of cellular component biogenesis, immune system process, and response to stimulus, were significantly enriched in non-additive proteins, probably providing a driving force for variation and adaptation in allopolyploids. In particular, majority of the total 452 differentially expressed proteins showed expression level dominance of one parental expression, and there was an expression level dominance bias toward the tetraploid progenitor. In addition, the percentage of differentially expressed proteins that matched previously reported differentially genes were relatively low. BIOLOGICAL SIGNIFICANCE This study aimed to get new insights into the effects of polyploidization on proteomic divergence. Using iTRAQ LC-MS/MS technology, we identified 452 differentially expressed proteins between allopolyploid and its parents which involved in response to stimulus, multi-organism process, and immune system process, much more than previous studies using 2-DE coupled with mass spectrometry technology. Therefore, our manuscript represents the most comprehensive analysis of protein profiles in allopolyploid and its parents, which will lead to a better understanding of novelty and plasticity of the allopolyploid genomes.
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Affiliation(s)
- Yanyue Shen
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yu Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jun Zou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Jinling Meng
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China
| | - Jianbo Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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35
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Shpylchyn VV, Antonyuk MZ, Ternovska TK. Genetic analysis of artificial Triticinae amphidiploid Aurotica based on the glaucousness trait. CYTOL GENET+ 2014. [DOI: 10.3103/s0095452714050107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Warren IA, Ciborowski KL, Casadei E, Hazlerigg DG, Martin S, Jordan WC, Sumner S. Extensive local gene duplication and functional divergence among paralogs in Atlantic salmon. Genome Biol Evol 2014; 6:1790-805. [PMID: 24951567 PMCID: PMC4122929 DOI: 10.1093/gbe/evu131] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/13/2014] [Indexed: 12/30/2022] Open
Abstract
Many organisms can generate alternative phenotypes from the same genome, enabling individuals to exploit diverse and variable environments. A prevailing hypothesis is that such adaptation has been favored by gene duplication events, which generate redundant genomic material that may evolve divergent functions. Vertebrate examples of recent whole-genome duplications are sparse although one example is the salmonids, which have undergone a whole-genome duplication event within the last 100 Myr. The life-cycle of the Atlantic salmon, Salmo salar, depends on the ability to produce alternating phenotypes from the same genome, to facilitate migration and maintain its anadromous life history. Here, we investigate the hypothesis that genome-wide and local gene duplication events have contributed to the salmonid adaptation. We used high-throughput sequencing to characterize the transcriptomes of three key organs involved in regulating migration in S. salar: Brain, pituitary, and olfactory epithelium. We identified over 10,000 undescribed S. salar sequences and designed an analytic workflow to distinguish between paralogs originating from local gene duplication events or from whole-genome duplication events. These data reveal that substantial local gene duplications took place shortly after the whole-genome duplication event. Many of the identified paralog pairs have either diverged in function or become noncoding. Future functional genomics studies will reveal to what extent this rich source of divergence in genetic sequence is likely to have facilitated the evolution of extreme phenotypic plasticity required for an anadromous life-cycle.
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Affiliation(s)
- Ian A Warren
- School of Biological Sciences, University of Bristol, United Kingdom
| | - Kate L Ciborowski
- School of Biological Sciences, University of Bristol, United KingdomInstitute of Zoology, Zoological Society of London, London, United Kingdom
| | - Elisa Casadei
- Institute of Biological and Environmental Sciences, University of Aberdeen, United Kingdom
| | - David G Hazlerigg
- Institute of Biological and Environmental Sciences, University of Aberdeen, United KingdomDepartment of Arctic and Marine Biology, Faculty of BioSciences Fisheries & Economy, University of Tromsø, Norway
| | - Sam Martin
- Institute of Biological and Environmental Sciences, University of Aberdeen, United Kingdom
| | - William C Jordan
- Institute of Zoology, Zoological Society of London, London, United Kingdom
| | - Seirian Sumner
- School of Biological Sciences, University of Bristol, United KingdomInstitute of Zoology, Zoological Society of London, London, United Kingdom
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Shen Y, Zhao Q, Zou J, Wang W, Gao Y, Meng J, Wang J. Characterization and expression patterns of small RNAs in synthesized Brassica hexaploids. PLANT MOLECULAR BIOLOGY 2014; 85:287-99. [PMID: 24584845 DOI: 10.1007/s11103-014-0185-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 02/24/2014] [Indexed: 05/14/2023]
Abstract
Polyploidy has played an important role in promoting plant evolution through genomic merging and doubling. We used high-throughput sequencing to compare miRNA expression profiles between Brassica hexaploid and its parents. A total of 613, 784 and 742 known miRNAs were identified in Brassica rapa, Brassica carinata, and Brassica hexaploid, respectively. We detected 618 miRNAs were differentially expressed (log(2)Ratio ≥ 1, P ≤ 0.05) between Brassica hexaploid and its parents, and 425 miRNAs were non-additively expressed in Brassica hexaploid, which suggest a trend of non-additive miRNA regulation following hybridization and polyploidization. Remarkably, majority of the non-additively expressed miRNAs in the Brassica hexaploid are repressed, and there was a bias toward repression of B. rapa miRNAs, which is consistent with the progenitor-biased gene repression in the synthetic allopolyploids. In addition, we identified 653 novel mature miRNAs in Brassica hexaploid and its parents. Finally, we found that almost all the non-additive accumulation of siRNA clusters exhibited a low-parent pattern in Brassica hexaploid. Non-additive small RNA regulation is involved in a range of biological pathways, probably providing a driving force for variation and adaptation in allopolyploids.
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Affiliation(s)
- Yanyue Shen
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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Senerchia N, Felber F, Parisod C. Contrasting evolutionary trajectories of multiple retrotransposons following independent allopolyploidy in wild wheats. THE NEW PHYTOLOGIST 2014; 202:975-985. [PMID: 24548250 DOI: 10.1111/nph.12731] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 01/09/2014] [Indexed: 06/03/2023]
Abstract
Transposable elements (TEs) are expectedly central to genome evolution. To assess the impact of TEs in driving genome turnover, we used allopolyploid genomes, showing considerable deviation from the predicted additivity of their diploid progenitors and thus having undergone major restructuring. Genome survey sequencing was used to select 17 putatively active families of long terminal repeat retrotransposons. Genome-wide TE insertions were genotyped with sequence-specific amplified polymorphism (SSAP) in diploid progenitors and their derived polyploids, and compared with changes in random sequences to assess restructuring of four independent Aegilops allotetraploid genomes. Generally, TEs with different evolutionary trajectories from those of random sequences were identified. Thus, TEs presented family-specific and species-specific dynamics following polyploidy, as illustrated by Sabine showing proliferation in particular polyploids, but massive elimination in others. Contrasting with that, only a few families (BARE1 and Romani) showed proliferation in all polyploids. Overall, TE divergence between progenitors was strongly correlated with the degree of restructuring in polyploid TE fractions. TE families present evolutionary trajectories that are decoupled from genome-wide changes after allopolyploidy and have a pervasive impact on their restructuring.
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Affiliation(s)
- Natacha Senerchia
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
| | - François Felber
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
- Musée et Jardins botaniques cantonaux, Avenue de Cour 14bis, 1007, Lausanne, Switzerland
| | - Christian Parisod
- Laboratory of Evolutionary Botany, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, 2000, Neuchâtel, Switzerland
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Panaud O, Jackson SA, Wendel JF. Drivers and dynamics of diversity in plant genomes. THE NEW PHYTOLOGIST 2014; 202:15-18. [PMID: 24571694 DOI: 10.1111/nph.12633] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- Olivier Panaud
- Université de Perpignan, UMR 5096 CNRS - IRD - UPVD, Perpignan, France
| | - Scott A Jackson
- Center for Applied Genetic Technologies, University of Georgia, 111 Riverbend Road, Athens, GA, 30602, USA
| | - Jonathan F Wendel
- Department of Ecology, Evolution, & Organismal Biology, Iowa State University, Ames, IA, 50011, USA
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Vitte C, Fustier MA, Alix K, Tenaillon MI. The bright side of transposons in crop evolution. Brief Funct Genomics 2014; 13:276-95. [PMID: 24681749 DOI: 10.1093/bfgp/elu002] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The past decades have revealed an unexpected yet prominent role of so-called 'junk DNA' in the regulation of gene expression, thereby challenging our view of the mechanisms underlying phenotypic evolution. In particular, several mechanisms through which transposable elements (TEs) participate in functional genome diversity have been depicted, bringing to light the 'TEs bright side'. However, the relative contribution of those mechanisms and, more generally, the importance of TE-based polymorphisms on past and present phenotypic variation in crops species remain poorly understood. Here, we review current knowledge on both issues, and discuss how analyses of massively parallel sequencing data combined with statistical methodologies and functional validations will help unravelling the impact of TEs on crop evolution in a near future.
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Sarilar V, Palacios P, Alix K. Detection of Transposable Element Insertion Site Polymorphisms by Sequence-Specific Amplification Polymorphism (SSAP). Bio Protoc 2014. [DOI: 10.21769/bioprotoc.1054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
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Wei L, An Z, Mason AS, Xiao M, Guo Y, Yin J, Li J, Fu D. Extensive tRNA gene changes in synthetic Brassica napus. J Mol Evol 2013; 78:38-49. [PMID: 24271856 DOI: 10.1007/s00239-013-9598-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Accepted: 11/11/2013] [Indexed: 12/12/2022]
Abstract
Allopolyploidization, where two species come together to form a new species, plays a major role in speciation and genome evolution. Transfer RNAs (abbreviated tRNA) are typically 73-94 nucleotides in length, and are indispensable in protein synthesis, transferring amino acids to the cell protein synthesis machinery (ribosome). To date, the regularity and function of tRNA gene sequence variation during the process of allopolyploidization have not been well understood. In this study, the inter-tRNA gene corresponding to tRNA amplification polymorphism method was used to detect changes in tRNA gene sequences in the progeny of interspecific hybrids between Brassica rapa and B. oleracea, mimicking the original B. napus (canola) species formation event. Cluster analysis showed that tRNA gene variation during allopolyploidization did not appear to have a genotypic basis. Significant variation occurred in the early generations of synthetic B. napus (F1 and F2 generations), but fewer alterations were observed in the later generation (F3). The variation-prone tRNA genes tended to be located in AT-rich regions. BlastN analysis of novel tRNA gene variants against a Brassica genome sequence database showed that the variation of these tRNA-gene-associated sequences in allopolyploidization might result in variation of gene structure and function, e.g., metabolic process and transport.
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Affiliation(s)
- Lijuan Wei
- Chongqing Engineering Research Center for Rapeseed, College of Agronomy and Biotechnology, Southwest University, Chongqing, 400716, China
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Bento M, Tomás D, Viegas W, Silva M. Retrotransposons represent the most labile fraction for genomic rearrangements in polyploid plant species. Cytogenet Genome Res 2013; 140:286-94. [PMID: 23899810 DOI: 10.1159/000353308] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Understanding how increased genome size and diversity within polyploid genomes impacts plant evolution and breeding continues to be challenging. Although historical studies by McClintock suggested the importance of transposable elements mediated by polyploidisation on genomic changes, data from plant crosses remain scarce. Despite the absence of a conclusive proof regarding autonomous retrotransposon movement in synthetic allopolyploids, the transposition of retrotransposons and their ubiquitous dispersion in all plant species might explain the positive correlation between the genome size of plants and the prevalence of retrotransposons. Here, we address polyploidisation-mediated rearrangements of retrotransposon-associated sequences and discuss a tendency for a preferential restructuring of large ancestral genomes after polyploidisation. A comparative analysis of the frequency of modifications of retrotransposon-associated sequences in synthetic polyploids with marked differences in genome sizes is presented. Such analyses suggest the absence of a significant difference in the rates of rearrangements despite vast dissimilarities in the retrotransposon copy number between species, which emphasises the high plasticity of this genomic feature. See also the sister article focusing on animals by Arkhipova and Rodriguez in this themed issue.
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Affiliation(s)
- M Bento
- Centro de Botânica Aplicada à Agricultura, Secção de Genética, Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Lisboa, Portugal
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