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Dallaire A, Manley BF, Wilkens M, Bista I, Quan C, Evangelisti E, Bradshaw CR, Ramakrishna NB, Schornack S, Butter F, Paszkowski U, Miska EA. Transcriptional activity and epigenetic regulation of transposable elements in the symbiotic fungus Rhizophagus irregularis. Genome Res 2021; 31:2290-2302. [PMID: 34772700 PMCID: PMC8647823 DOI: 10.1101/gr.275752.121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Accepted: 09/16/2021] [Indexed: 11/29/2022]
Abstract
Arbuscular mycorrhizal (AM) fungi form mutualistic relationships with most land plant species. AM fungi have long been considered as ancient asexuals. Long-term clonal evolution would be remarkable for a eukaryotic lineage and suggests the importance of alternative mechanisms to promote genetic variability facilitating adaptation. Here, we assessed the potential of transposable elements for generating such genomic diversity. The dynamic expression of TEs during Rhizophagus irregularis spore development suggests ongoing TE activity. We find Mutator-like elements located near genes belonging to highly expanded gene families. Whole-genome epigenomic profiling of R. irregularis provides direct evidence of DNA methylation and small RNA production occurring at TE loci. Our results support a model in which TE activity shapes the genome, while DNA methylation and small RNA-mediated silencing keep their overproliferation in check. We propose that a well-controlled TE activity directly contributes to genome evolution in AM fungi.
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Affiliation(s)
- Alexandra Dallaire
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
- Tree of Life, Wellcome Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Bethan F Manley
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
- Tree of Life, Wellcome Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Maya Wilkens
- Quantitative Proteomics, Institute of Molecular Biology, 55128 Mainz, Germany
| | - Iliana Bista
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
- Tree of Life, Wellcome Sanger Institute, Cambridge CB10 1SA, United Kingdom
| | - Clement Quan
- Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, United Kingdom
| | - Edouard Evangelisti
- Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, United Kingdom
| | - Charles R Bradshaw
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
| | - Navin B Ramakrishna
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
| | - Sebastian Schornack
- Sainsbury Laboratory, University of Cambridge, Cambridge CB2 1LR, United Kingdom
| | - Falk Butter
- Quantitative Proteomics, Institute of Molecular Biology, 55128 Mainz, Germany
| | - Uta Paszkowski
- Crop Science Centre, University of Cambridge, Cambridge CB3 0LE, United Kingdom
| | - Eric A Miska
- Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, Cambridge CB2 1QN, United Kingdom
- Department of Genetics, University of Cambridge, Cambridge CB2 3EH, United Kingdom
- Tree of Life, Wellcome Sanger Institute, Cambridge CB10 1SA, United Kingdom
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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: 6] [Impact Index Per Article: 1.5] [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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Richard MMS, Gratias A, Thareau V, Kim KD, Balzergue S, Joets J, Jackson SA, Geffroy V. Genomic and epigenomic immunity in common bean: the unusual features of NB-LRR gene family. DNA Res 2018; 25:161-172. [PMID: 29149287 PMCID: PMC5909424 DOI: 10.1093/dnares/dsx046] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 10/26/2017] [Indexed: 12/20/2022] Open
Abstract
In plants, a key class of genes comprising most of disease resistance (R) genes encodes Nucleotide-binding leucine-rich repeat (NL) proteins. Access to common bean (Phaseolus vulgaris) genome sequence provides unparalleled insight into the organization and evolution of this large gene family (∼400 NL) in this important crop. As observed in other plant species, most common bean NL are organized in cluster of genes. However, a particularity of common bean is that these clusters are often located in subtelomeric regions close to terminal knobs containing the satellite DNA khipu. Phylogenetically related NL are spread between different chromosome ends, suggesting frequent exchanges between non-homologous chromosomes. NL peculiar location, in proximity to heterochromatic regions, led us to study their DNA methylation status using a whole-genome cytosine methylation map. In common bean, NL genes displayed an unusual body methylation pattern since half of them are methylated in the three contexts, reminiscent of the DNA methylation pattern of repeated sequences. Moreover, 90 NL were also abundantly targeted by 24 nt siRNA, with 90% corresponding to methylated NL genes. This suggests the existence of a transcriptional gene silencing mechanism of NL through the RdDM (RNA-directed DNA methylation) pathway in common bean that has not been described in other plant species.
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Affiliation(s)
- Manon M S Richard
- Institute of Plant Sciences Paris-Saclay IPS2, CNRS, INRA, Univ Paris-Saclay, Univ Paris-Sud, Univ Evry, Univ Paris-Diderot, Sorbone Paris-Cité, 91405 Orsay, France
| | - Ariane Gratias
- Institute of Plant Sciences Paris-Saclay IPS2, CNRS, INRA, Univ Paris-Saclay, Univ Paris-Sud, Univ Evry, Univ Paris-Diderot, Sorbone Paris-Cité, 91405 Orsay, France
| | - Vincent Thareau
- Institute of Plant Sciences Paris-Saclay IPS2, CNRS, INRA, Univ Paris-Saclay, Univ Paris-Sud, Univ Evry, Univ Paris-Diderot, Sorbone Paris-Cité, 91405 Orsay, France
| | - Kyung Do Kim
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA 30602, USA
| | - Sandrine Balzergue
- Institute of Plant Sciences Paris-Saclay IPS2, CNRS, INRA, Univ Paris-Saclay, Univ Paris-Sud, Univ Evry, Univ Paris-Diderot, Sorbone Paris-Cité, 91405 Orsay, France
- IRHS, INRA, AGROCAMPUS-Ouest, Université d’Angers, SFR 4207 QUASAV, 49071 Beaucouzé cedex, France
| | - Johann Joets
- GQE – Le Moulon, INRA, Univ. Paris-Sud, CNRS, AgroParisTech, Université Paris-Saclay, 91190 Gif-sur-Yvette, France
| | - Scott A Jackson
- Center for Applied Genetic Technologies, University of Georgia, Athens, GA 30602, USA
| | - Valérie Geffroy
- Institute of Plant Sciences Paris-Saclay IPS2, CNRS, INRA, Univ Paris-Saclay, Univ Paris-Sud, Univ Evry, Univ Paris-Diderot, Sorbone Paris-Cité, 91405 Orsay, France
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Bousios A, Gaut BS, Darzentas N. Considerations and complications of mapping small RNA high-throughput data to transposable elements. Mob DNA 2017; 8:3. [PMID: 28228849 PMCID: PMC5311732 DOI: 10.1186/s13100-017-0086-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2016] [Accepted: 01/31/2017] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND High-throughput sequencing (HTS) has revolutionized the way in which epigenetic research is conducted. When coupled with fully-sequenced genomes, millions of small RNA (sRNA) reads are mapped to regions of interest and the results scrutinized for clues about epigenetic mechanisms. However, this approach requires careful consideration in regards to experimental design, especially when one investigates repetitive parts of genomes such as transposable elements (TEs), or when such genomes are large, as is often the case in plants. RESULTS Here, in an attempt to shed light on complications of mapping sRNAs to TEs, we focus on the 2,300 Mb maize genome, 85% of which is derived from TEs, and scrutinize methodological strategies that are commonly employed in TE studies. These include choices for the reference dataset, the normalization of multiply mapping sRNAs, and the selection among sRNA metrics. We further examine how these choices influence the relationship between sRNAs and the critical feature of TE age, and contrast their effect on low copy genomic regions and other popular HTS data. CONCLUSIONS Based on our analyses, we share a series of take-home messages that may help with the design, implementation, and interpretation of high-throughput TE epigenetic studies specifically, but our conclusions may also apply to any work that involves analysis of HTS data.
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Affiliation(s)
- Alexandros Bousios
- School of Life Sciences, University of Sussex, Brighton, East Sussex BN1 9RH UK
| | - Brandon S. Gaut
- Department of Ecology and Evolutionary Biology, UC Irvine, Irvine, CA 92697 USA
| | - Nikos Darzentas
- Central European Institute of Technology, Masaryk University, Brno, 62500 Czech Republic
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Ferreira de Carvalho J, de Jager V, van Gurp TP, Wagemaker NCAM, Verhoeven KJF. Recent and dynamic transposable elements contribute to genomic divergence under asexuality. BMC Genomics 2016; 17:884. [PMID: 27821059 PMCID: PMC5100183 DOI: 10.1186/s12864-016-3234-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 11/01/2016] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Transposable elements (TEs) are mobile pieces of genetic information with high mutagenic potential for the host genome. Transposition is often neutral or deleterious but may also generate potentially adaptive genetic variation. This additional source of variation could be especially relevant in non-recombining species reproducing asexually. However, evidence is lacking to determine the relevance of TEs in plant asexual genome evolution and their associated effects. Here, we characterize the repetitive fraction of the genome of the common dandelion, Taraxacum officinale and compare it between five accessions from the same apomictic lineage. The main objective of this study is to evaluate the extent of within-lineage divergence attributed to TE content and activity. We examined the repetitive genomic contribution, diversity, transcription and methylation changes to characterize accession-specific TEs. RESULTS Using low-coverage genomic sequencing, we report a highly heterogeneous TE compartment in the triploid apomict T. officinale representing up to 38.6 % of the homoploid genome. The repetitive compartment is dominated by LTR retrotransposon families accompanied by few non-LTR retrotransposons and DNA transposons. Up to half of the repeat clusters are biased towards very high read identity, indicating recent and potentially ongoing activity of these TE families. Interestingly, the five accessions are divided into two main clades based on their TE composition. Clade 2 is more dynamic than clade 1 with higher abundance of Gypsy Chromovirus sequences and transposons. Furthermore, a few low-abundant genomic TE clusters exhibit high level of transcription in two of the accessions analysed. Using reduced representation bisulfite sequencing, we detected 18.9 % of loci differentially methylated, of which 25.4 and 40.7 % are annotated as TEs or functional genes, respectively. Additionally, we show clear evidence for accession-specific TE families that are differentially transcribed and differentially methylated within the apomictic lineage, including one Copia Ale II LTR element and a PIF-Harbinger DNA transposon. CONCLUSION We report here a very young and dynamic repetitive compartment that enhances divergence within one asexual lineage of T. officinale. We speculate that accession-specific TE families that are both transcriptionally and epigenetically variable are more prone to trigger changes in expression on nearby coding sequences. These findings emphasize the potential of TE-induced mutations on functional genes during asexual genome evolution.
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Affiliation(s)
- Julie Ferreira de Carvalho
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Victor de Jager
- Bioinformatic Support Group, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Thomas P. van Gurp
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Niels C. A. M. Wagemaker
- Experimental Plant Ecology, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands
| | - Koen J. F. Verhoeven
- Department of Terrestrial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
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