1
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Shi T, Zhang X, Hou Y, Jia C, Dan X, Zhang Y, Jiang Y, Lai Q, Feng J, Feng J, Ma T, Wu J, Liu S, Zhang L, Long Z, Chen L, Street NR, Ingvarsson PK, Liu J, Yin T, Wang J. The super-pangenome of Populus unveils genomic facets for its adaptation and diversification in widespread forest trees. MOLECULAR PLANT 2024; 17:725-746. [PMID: 38486452 DOI: 10.1016/j.molp.2024.03.009] [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: 10/09/2023] [Revised: 02/22/2024] [Accepted: 03/11/2024] [Indexed: 04/05/2024]
Abstract
Understanding the underlying mechanisms and links between genome evolution and adaptive innovations stands as a key goal in evolutionary studies. Poplars, among the world's most widely distributed and cultivated trees, exhibit extensive phenotypic diversity and environmental adaptability. In this study, we present a genus-level super-pangenome comprising 19 Populus genomes, revealing the likely pivotal role of private genes in facilitating local environmental and climate adaptation. Through the integration of pangenomes with transcriptomes, methylomes, and chromatin accessibility mapping, we unveil that the evolutionary trajectories of pangenes and duplicated genes are closely linked to local genomic landscapes of regulatory and epigenetic architectures, notably CG methylation in gene-body regions. Further comparative genomic analyses have enabled the identification of 142 202 structural variants across species that intersect with a significant number of genes and contribute substantially to both phenotypic and adaptive divergence. We have experimentally validated a ∼180-bp presence/absence variant affecting the expression of the CUC2 gene, crucial for leaf serration formation. Finally, we developed a user-friendly web-based tool encompassing the multi-omics resources associated with the Populus super-pangenome (http://www.populus-superpangenome.com). Together, the present pioneering super-pangenome resource in forest trees not only aids in the advancement of breeding efforts of this globally important tree genus but also offers valuable insights into potential avenues for comprehending tree biology.
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Affiliation(s)
- Tingting Shi
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Xinxin Zhang
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Yukang Hou
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Changfu Jia
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Xuming Dan
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Yulin Zhang
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Yuanzhong Jiang
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Qiang Lai
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Jiajun Feng
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Jianju Feng
- College of Horticulture and Forestry, Tarim University, Alar 843300, China
| | - Tao Ma
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Jiali Wu
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Shuyu Liu
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Lei Zhang
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Zhiqin Long
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Liyang Chen
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China
| | - Nathaniel R Street
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, Västerbotten, Sweden
| | - Pär K Ingvarsson
- Linnean Centre for Plant Biology, Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala, Sweden
| | - Jianquan Liu
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China.
| | - Tongming Yin
- The Key Laboratory of Tree Genetics and Biotechnology of Jiangsu Province and Education Department of China, Nanjing Forestry University, Nanjing, Jiangsu, China.
| | - Jing Wang
- Key Laboratory for Bio-Resources and Eco-Environment of Ministry of Education, College of Life Sciences, Sichuan University, Chengdu, Sichuan, China.
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2
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Huang Y, Lee YCG. Blessing or curse: how the epigenetic resolution of host-transposable element conflicts shapes their evolutionary dynamics. Proc Biol Sci 2024; 291:20232775. [PMID: 38593848 PMCID: PMC11003778 DOI: 10.1098/rspb.2023.2775] [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: 12/08/2023] [Accepted: 03/01/2024] [Indexed: 04/11/2024] Open
Abstract
Transposable elements (TEs) are selfish genetic elements whose antagonistic interactions with hosts represent a common genetic conflict in eukaryotes. To resolve this conflict, hosts have widely adopted epigenetic silencing that deposits repressive marks at TEs. However, this mechanism is imperfect and fails to fully halt TE replication. Furthermore, TE epigenetic silencing can inadvertently spread repressive marks to adjacent functional sequences, a phenomenon considered a 'curse' of this conflict resolution. Here, we used forward simulations to explore how TE epigenetic silencing and its harmful side effects shape the evolutionary dynamics of TEs and their hosts. Our findings reveal that epigenetic silencing allows TEs and their hosts to stably coexist under a wide range of conditions, because the underlying molecular mechanisms give rise to copy-number dependency of the strength of TE silencing. Interestingly, contrary to intuitive expectations that TE epigenetic silencing should evolve to be as strong as possible, we found a selective benefit for modifier alleles that weaken TE silencing under biologically feasible conditions. These results reveal that the dual nature of TE epigenetic silencing, with both positive and negative effects, complicates its evolutionary trajectory and makes it challenging to determine whether TE epigenetic silencing is a 'blessing' or a 'curse'.
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Affiliation(s)
- Yuheng Huang
- Department of Ecology and Evolutionary Biology, University of California, Irvine, USA
| | - Yuh Chwen G. Lee
- Department of Ecology and Evolutionary Biology, University of California, Irvine, USA
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3
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Meca E, Díez CM, Gaut BS. Modeling transposable elements dynamics during polyploidization in plants. J Theor Biol 2024; 579:111701. [PMID: 38128754 DOI: 10.1016/j.jtbi.2023.111701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 11/24/2023] [Accepted: 12/08/2023] [Indexed: 12/23/2023]
Abstract
In this work we study the proliferation of transposable elements (TEs) and the epigenetic response of plants during the process of polyploidization. Through a deterministic model, expanding on our previous work on TE proliferation under epigenetic regulation, we study the long-term TE distribution and TE stability in the subgenomes of both autopolyploids and allopolyploids. We also explore different small-interfering RNA (siRNA) action modes on the subgenomes, including a model where siRNAs are not directed to specific genomes and one where siRNAs are directed - i.e. more active - in subgenomes with higher TE loads. In the autopolyploid case, we find long-term stable equilbria that tend to equilibrate the number of active TEs between subgenomes. In the allopolyploid case, directed siRNA action is fundamental to avoid a "winner takes all" outcome of the competition between the TEs in the different subgenomes. We also show that decaying oscillations in the number of TEs occur naturally in all cases, perhaps explaining some of the observed features of 'genomic shock' after hybridization events, and that the balance in the dynamics of the different types of siRNA is determinant for the synchronization of these oscillations.
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Affiliation(s)
- Esteban Meca
- Departamento de Física Aplicada, Radiología y Medicina Física, Universidad de Córdoba, Campus Universitario de Rabanales, Edificio Albert Einstein (C2), 14014 Córdoba, Spain.
| | - Concepción M Díez
- Departamento de Agronomía, Universidad de Córdoba, Campus Universitario de Rabanales, Edificio Celestino Mutis (C4), 14014 Córdoba, Spain.
| | - Brandon S Gaut
- Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697-3875, United States of America.
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4
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Martin GT, Solares E, Guadardo-Mendez J, Muyle A, Bousios A, Gaut BS. miRNA-like secondary structures in maize ( Zea mays) genes and transposable elements correlate with small RNAs, methylation, and expression. Genome Res 2023; 33:gr.277459.122. [PMID: 37918960 PMCID: PMC10760457 DOI: 10.1101/gr.277459.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 10/16/2023] [Indexed: 11/04/2023]
Abstract
RNA molecules carry information in their primary sequence and also their secondary structure. Secondary structure can confer important functional information, but it is also a signal for an RNAi-like host epigenetic response mediated by small RNAs (smRNAs). In this study, we used two bioinformatic methods to predict local secondary structures across features of the maize genome, focusing on small regions that had similar folding properties to pre-miRNA loci. We found miRNA-like secondary structures to be common in genes and most, but not all, superfamilies of RNA and DNA transposable elements (TEs). The miRNA-like regions map to a higher diversity of smRNAs than regions without miRNA-like structure, explaining up to 27% of variation in smRNA mapping for some TE superfamilies. This mapping bias is more pronounced among putatively autonomous TEs relative to nonautonomous TEs. Genome-wide, miRNA-like regions are also associated with elevated methylation levels, particularly in the CHH context. Among genes, those with miRNA-like secondary structure are 1.5-fold more highly expressed, on average, than other genes. However, these genes are also more variably expressed across the 26 nested association mapping founder lines, and this variability positively correlates with the number of mapping smRNAs. We conclude that local miRNA-like structures are a nearly ubiquitous feature of expressed regions of the maize genome, that they correlate with higher smRNA mapping and methylation, and that they may represent a trade-off between functional requirements and the potentially negative consequences of smRNA production.
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Affiliation(s)
- Galen T Martin
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92617, USA
| | - Edwin Solares
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92617, USA
- Department of Ecology and Evolutionary Biology, University of California, Davis, California 95616, USA
| | - Jeanelle Guadardo-Mendez
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92617, USA
| | - Aline Muyle
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92617, USA
- CEFE, University of Montpellier, CNRS, EPHE, IRD, 34090 Montpellier, France
| | - Alexandros Bousios
- School of Life Sciences, University of Sussex, Brighton BN1 9QG, United Kingdom
| | - Brandon S Gaut
- Department of Ecology and Evolutionary Biology, University of California, Irvine, California 92617, USA;
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Yang H, Shi X, Chen C, Hou J, Ji T, Cheng J, Birchler JA. Genomic imbalance modulates transposable element expression in maize. PLANT COMMUNICATIONS 2023; 4:100467. [PMID: 36307986 PMCID: PMC10030319 DOI: 10.1016/j.xplc.2022.100467] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 09/19/2022] [Accepted: 10/23/2022] [Indexed: 05/04/2023]
Abstract
Genomic imbalance refers to the more severe phenotypic consequences of changing part of a chromosome compared with the whole genome set. Previous genome imbalance studies in maize have identified prevalent inverse modulation of genes on the unvaried chromosomes (trans) with both the addition or subtraction of chromosome arms. Transposable elements (TEs) comprise a substantial fraction of the genome, and their reaction to genomic imbalance is therefore of interest. Here, we analyzed TE expression using RNA-seq data of aneuploidy and ploidy series and found that most aneuploidies showed an inverse modulation of TEs, but reductions in monosomy and increases in disomy and trisomy were also common. By contrast, the ploidy series showed little TE modulation. The modulation of TEs and genes in the same experimental group were compared, and TEs showed greater modulation than genes, especially in disomy. Class I and II TEs were differentially modulated in most aneuploidies, and some superfamilies in each TE class also showed differential modulation. Finally, the significantly upregulated TEs in three disomies (TB-7Lb, TB9Lc, and TB-10L19) did not increase the proportion of adjacent gene expression when compared with non-differentially expressed TEs, indicating that modulations of TEs do not compound the effect on genes. These results suggest that the prevalent inverse TE modulation in aneuploidy results from stoichiometric upset of the regulatory machinery used by TEs, similar to the response of core genes to genomic imbalance.
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Affiliation(s)
- Hua Yang
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Xiaowen Shi
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Chen Chen
- Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, MO 65211, USA
| | - Jie Hou
- Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, MO 65211, USA
| | - Tieming Ji
- Department of Statistics, University of Missouri, Columbia, MO 65211, USA
| | - Jianlin Cheng
- Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, MO 65211, USA
| | - James A Birchler
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA.
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Sammarco I, Pieters J, Salony S, Toman I, Zolotarov G, Lafon Placette C. Epigenetic targeting of transposon relics: beating the dead horses of the genome? Epigenetics 2022; 17:1331-1344. [PMID: 36255200 PMCID: PMC9586680 DOI: 10.1080/15592294.2021.2022066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Transposable elements (TEs) have been seen as selfish genetic elements that can propagate in a host genome. Their propagation success is however hindered by a combination of mechanisms such as mutations, selection, and their epigenetic silencing by the host genome. As a result, most copies of TEs in a given genome are dead relics: their sequence is too degenerated to allow any transposition. Nevertheless, these TE relics often, but not always, remain epigenetically silenced, and if not to prevent transposition anymore, one can wonder the reason for this phenomenon. The mere self-perpetuating loop inherent to epigenetic silencing could alone explain that even when inactive, TE copies remain silenced. Beyond this process, nevertheless, antagonistic selective forces are likely to act on TE relic silencing. Especially, without the benefit of preventing transposition, TE relic silencing may prove deleterious to the host fitness, suggesting that the maintenance of TE relic silencing is the result of a fine, and perhaps case-by-case, evolutionary trade-off between beneficial and deleterious effects. Ultimately, the release of TE relics silencing may provide a 'safe' ground for adaptive epimutations to arise. In this review, we provide an overview of these questions in both plants and animals.
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Affiliation(s)
- Iris Sammarco
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic,Institute of Botany, Czech Academy of Sciences, Pruhonice, Czech Republic
| | - Janto Pieters
- Laboratory of Pollen Biology, Institute of Experimental Botany, Czech Academy of Science, Prague, Czech Republic,Department of Plant Experimental Biology, Faculty of Science, Charles University, Prague, Czech Republic
| | - Susnata Salony
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic
| | - Izabela Toman
- Department of Anthropology and Human Genetics, Faculty of Science, Charles University, Prague, Czech Republic
| | - Grygoriy Zolotarov
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Clément Lafon Placette
- Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic,CONTACT Clément Lafon Placette Department of Botany, Faculty of Science, Charles University, PragueCZ-128 01, Czech Republic
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Characterization of Transposon-Derived Accessible Chromatin Regions in Rice (Oryza Sativa). Int J Mol Sci 2022; 23:ijms23168947. [PMID: 36012213 PMCID: PMC9408979 DOI: 10.3390/ijms23168947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 11/17/2022] Open
Abstract
Growing evidence indicates that transposons or transposable elements (TEs)-derived accessible chromatin regions (ACRs) play essential roles in multiple biological processes by interacting with trans-acting factors. However, the function of TE-derived ACRs in the regulation of gene expression in the rice genome has not been well characterized. In this study, we examined the chromatin dynamics in six types of rice tissues and found that ~8% of ACRs were derived from TEs and exhibited distinct levels of accessibility and conservation as compared to those without TEs. TEs exhibited a TE subtype-dependent impact on ACR formation, which can be mediated by changes in the underlying DNA methylation levels. Moreover, we found that tissue-specific TE-derived ACRs might function in the tissue development through the modulation of nearby gene expression. Interestingly, many genes in domestication sweeps were found to overlap with TE-derived ACRs, suggesting their potential functions in the rice domestication. In addition, we found that the expression divergence of 1070 duplicate gene pairs were associated with TE-derived ACRs and had distinct distributions of TEs and ACRs around the transcription start sites (TSSs), which may experience different selection pressures. Thus, our study provides some insights into the biological implications of TE-derived ACRs in the rice genome. Our results imply that these ACRs are likely involved in the regulation of tissue development, rice domestication and functional divergence of duplicated genes.
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8
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Dazenière J, Bousios A, Eyre-Walker A. Patterns of selection in the evolution of a transposable element. G3 GENES|GENOMES|GENETICS 2022; 12:6545286. [PMID: 35262706 PMCID: PMC9073684 DOI: 10.1093/g3journal/jkac056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2021] [Accepted: 02/14/2022] [Indexed: 11/23/2022]
Abstract
Transposable elements are a major component of most eukaryotic genomes. Here, we present a new approach which allows us to study patterns of natural selection in the evolution of transposable elements over short time scales. The method uses the alignment of all elements with intact gag/pol genes of a transposable element family from a single genome. We predict that the ratio of nonsynonymous to synonymous variants in the alignment should decrease as a function of the frequency of the variants, because elements with nonsynonymous variants that reduce transposition will have fewer progeny. We apply our method to Sirevirus long-terminal repeat retrotransposons that are abundant in maize and other plant species and show that nonsynonymous to synonymous variants declines as variant frequency increases, indicating that negative selection is acting strongly on the Sirevirus genome. The asymptotic value of nonsynonymous to synonymous variants suggests that at least 85% of all nonsynonymous mutations in the transposable element reduce transposition. Crucially, these patterns in nonsynonymous to synonymous variants are only predicted to occur if the gene products from a particular transposable element insertion preferentially promote the transposition of the same insertion. Overall, by using large numbers of intact elements, this study sheds new light on the selective processes that act on transposable elements.
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Affiliation(s)
- Julie Dazenière
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RH, UK
| | - Alexandros Bousios
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RH, UK
| | - Adam Eyre-Walker
- School of Life Sciences, University of Sussex, Falmer, Brighton BN1 9RH, UK
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9
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Minow MAA, Ávila LM, Lukens LN, Rossi V, Colasanti J. Introgressed DNA within a Zea mays near isogenic line displays lower levels of 24nt sRNA expression than the homologous region from the recurrent parent. Genome 2021; 64:1091-1098. [PMID: 34192470 DOI: 10.1139/gen-2021-0007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Near isogenic lines (NILs) are a classical genetic tool used to dissect the actions of an allele when placed in a uniform genetic background. Although the goal of NIL creation is to examine the effects of a single allele in isolation, DNA linked to the allele is invariably retained and can confound any allele specific effects. In addition to genetic variation, highly polymorphic species like Zea mays will contain introgressed polymorphisms encompassing transposable elements (TEs) and the cis acting small RNA (sRNA) that represses them. Through transcriptomics, we described the sRNA and TE transcriptional expression differences between a W22-derived introgression and its homologous B73 region. As anticipated, many sRNA expression differences were found. Unexpectedly, however, 24nt sRNA expression over the introgressed region was low overall compared to both the homologous B73 region and the rest of the genome. Across the introgression, low sRNA expression was accompanied by increased TE transcription. Possible explanations for the observed trends in sRNA and TE expression across the introgression are discussed. These findings support the notion that any introgressed allele is in an epigenetic environment distinct from that found at the allele from the recurrent parent. Additionally, these results suggest that further study of sRNA expression levels during the introgression process is warranted.
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Affiliation(s)
- Mark A A Minow
- University of Guelph, 3653, Molecular and Cellular Biology, 50 Stone Rd East, ON, Guelph, Ontario, Canada, N1G 2W1;
| | - Luis M Ávila
- University of Guelph, 3653, Plant Agriculture Department, Guelph, Ontario, Canada;
| | - Lewis N Lukens
- University of Guelph, Department of Plant Agriculture, Guelph Campus, Guelph, Ontario, Canada, N1G 2W1;
| | - Vincenzo Rossi
- Research Centre for Cereal and Industrial Crops, Bergamo, Italy;
| | - Joseph Colasanti
- University of Guelph, 3653, Department of Molecular and Cellular Biology, Guelph, Ontario, Canada, N1G 2W1;
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10
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Pourrajab F, Hekmatimoghaddam S. Transposable elements, contributors in the evolution of organisms (from an arms race to a source of raw materials). Heliyon 2021; 7:e06029. [PMID: 33532648 PMCID: PMC7829209 DOI: 10.1016/j.heliyon.2021.e06029] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 10/08/2020] [Accepted: 01/13/2021] [Indexed: 12/19/2022] Open
Abstract
There is a concept proposing that the primitive lineages of prokaryotes, eukaryotes, and viruses emerged from the primordial pool of primitive genetic elements. In this genetic pool, transposable elements (TEs) became a source of raw material for primitive genomes, tools of genetic innovation, and ancestors of modern genes (e.g. ncRNAs, tRNAs, and rRNAs). TEs contributed directly to the genome evolution of three forms of life on the earth. TEs now appear as tools that were used to giving rise to sexual dimorphism and sex determination, lineage-specific expression of genes and tissue differentiation and finally genome stability and lifespan determination.
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Affiliation(s)
- Fatemeh Pourrajab
- Nutrition and Food Security Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.,Department of Biochemistry and Molecular Biology, School of Medicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Seyedhossein Hekmatimoghaddam
- Department of Advanced Medical Sciences and Technologies, School of Paramedicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran.,Department of Laboratory Sciences, School of Paramedicine, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
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11
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Price TAR, Windbichler N, Unckless RL, Sutter A, Runge JN, Ross PA, Pomiankowski A, Nuckolls NL, Montchamp-Moreau C, Mideo N, Martin OY, Manser A, Legros M, Larracuente AM, Holman L, Godwin J, Gemmell N, Courret C, Buchman A, Barrett LG, Lindholm AK. Resistance to natural and synthetic gene drive systems. J Evol Biol 2020; 33:1345-1360. [PMID: 32969551 PMCID: PMC7796552 DOI: 10.1111/jeb.13693] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Revised: 08/10/2020] [Accepted: 08/13/2020] [Indexed: 02/06/2023]
Abstract
Scientists are rapidly developing synthetic gene drive elements intended for release into natural populations. These are intended to control or eradicate disease vectors and pests, or to spread useful traits through wild populations for disease control or conservation purposes. However, a crucial problem for gene drives is the evolution of resistance against them, preventing their spread. Understanding the mechanisms by which populations might evolve resistance is essential for engineering effective gene drive systems. This review summarizes our current knowledge of drive resistance in both natural and synthetic gene drives. We explore how insights from naturally occurring and synthetic drive systems can be integrated to improve the design of gene drives, better predict the outcome of releases and understand genomic conflict in general.
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Affiliation(s)
- Tom A. R. Price
- Department of Ecology, Evolution and Behaviour, University of Liverpool, Liverpool L69 7ZB, UK
| | - Nikolai Windbichler
- Department of Life Sciences, Imperial College London, South Kensington Campus, London SW7 2AZ, UK
| | | | - Andreas Sutter
- School of Biological Sciences, Norwich Research Park, University of East Anglia, Norwich NR4 7TJ, UK
| | - Jan-Niklas Runge
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057 Zurich, Switzerland
| | - Perran A. Ross
- Bio21 and the School of Biosciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Andrew Pomiankowski
- Department of Genetics, Evolution and Environment, University College London, Gower Street, London WC1E 6BT, UK
| | | | - Catherine Montchamp-Moreau
- Evolution Génome Comportement et Ecologie, CNRS, IRD, Université Paris-Saclay, Gif sur Yvette 91190, France
| | - Nicole Mideo
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto, ON M5S 3B2 Canada
| | - Oliver Y. Martin
- Department of Biology (D-BIOL) & Institute of Integrative Biology (IBZ), ETH Zurich, Universitätsstrasse 16, CH 8092 Zurich, Switzerland
| | - Andri Manser
- Department of Ecology, Evolution and Behaviour, University of Liverpool, Liverpool L69 7ZB, UK
| | - Matthieu Legros
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia
| | | | - Luke Holman
- School of Biosciences, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - John Godwin
- Department of Biological Sciences, North Carolina State University, Raleigh, NC 27695, USA
| | - Neil Gemmell
- Department of Anatomy, University of Otago, Dunedin 9054, New Zealand
| | - Cécile Courret
- Evolution Génome Comportement et Ecologie, CNRS, IRD, Université Paris-Saclay, Gif sur Yvette 91190, France
- Department of Biology, University of Rochester, Rochester, New York, USA
| | - Anna Buchman
- University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093
- Verily Life Sciences, 269 E Grand Ave, South San Francisco, CA 94080
| | - Luke G. Barrett
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia
| | - Anna K. Lindholm
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057 Zurich, Switzerland
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12
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Disrupting the disruptors: the consequences of mutations in mobile elements for ecologically important life history traits. Evol Ecol 2020. [DOI: 10.1007/s10682-020-10038-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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13
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Abstract
Epigenetic changes influence gene expression and contribute to the modulation of biological processes in response to the environment. Transgenerational epigenetic changes in gene expression have been described in many eukaryotes. However, plants appear to have a stronger propensity for inheriting novel epialleles. This mini-review discusses how plant traits, such as meristematic growth, totipotency, and incomplete epigenetic erasure in gametes promote epiallele inheritance. Additionally, we highlight how plant biology may be inherently tailored to reap the benefits of epigenetic metastability. Importantly, environmentally triggered small RNA expression and subsequent epigenetic changes may allow immobile plants to adapt themselves, and possibly their progeny, to thrive in local environments. The change of epigenetic states through the passage of generations has ramifications for evolution in the natural and agricultural world. In populations containing little genetic diversity, such as elite crop germplasm or habitually self-reproducing species, epigenetics may provide an important source of heritable phenotypic variation. Basic understanding of the processes that direct epigenetic shifts in the genome may allow for breeding or bioengineering for improved plant traits that do not require changes to DNA sequence.
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Affiliation(s)
- Mark A A Minow
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada.,Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Joseph Colasanti
- Department of Molecular and Cellular Biology, University of Guelph, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
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14
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Abstract
Chromosome organisation is increasingly recognised as an essential component of genome regulation, cell fate and cell health. Within the realm of transposable elements (TEs) however, the spatial information of how genomes are folded is still only rarely integrated in experimental studies or accounted for in modelling. Whilst polymer physics is recognised as an important tool to understand the mechanisms of genome folding, in this commentary we discuss its potential applicability to aspects of TE biology. Based on recent works on the relationship between genome organisation and TE integration, we argue that existing polymer models may be extended to create a predictive framework for the study of TE integration patterns. We suggest that these models may offer orthogonal and generic insights into the integration profiles (or "topography") of TEs across organisms. In addition, we provide simple polymer physics arguments and preliminary molecular dynamics simulations of TEs inserting into heterogeneously flexible polymers. By considering this simple model, we show how polymer folding and local flexibility may generically affect TE integration patterns. The preliminary discussion reported in this commentary is aimed to lay the foundations for a large-scale analysis of TE integration dynamics and topography as a function of the three-dimensional host genome.
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15
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Lv Y, Hu F, Zhou Y, Wu F, Gaut BS. Maize transposable elements contribute to long non-coding RNAs that are regulatory hubs for abiotic stress response. BMC Genomics 2019; 20:864. [PMID: 31729949 PMCID: PMC6858665 DOI: 10.1186/s12864-019-6245-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 10/30/2019] [Indexed: 02/07/2023] Open
Abstract
Background Several studies have mined short-read RNA sequencing datasets to identify long non-coding RNAs (lncRNAs), and others have focused on the function of individual lncRNAs in abiotic stress response. However, our understanding of the complement, function and origin of lncRNAs – and especially transposon derived lncRNAs (TE-lncRNAs) - in response to abiotic stress is still in its infancy. Results We utilized a dataset of 127 RNA sequencing samples that included total RNA datasets and PacBio fl-cDNA data to discover lncRNAs in maize. Overall, we identified 23,309 candidate lncRNAs from polyA+ and total RNA samples, with a strong discovery bias within total RNA. The majority (65%) of the 23,309 lncRNAs had sequence similarity to transposable elements (TEs). Most had similarity to long-terminal-repeat retrotransposons from the Copia and Gypsy superfamilies, reflecting a high proportion of these elements in the genome. However, DNA transposons were enriched for lncRNAs relative to their genomic representation by ~ 2-fold. By assessing the fraction of lncRNAs that respond to abiotic stresses like heat, cold, salt and drought, we identified 1077 differentially expressed lncRNA transcripts, including 509 TE-lncRNAs. In general, the expression of these lncRNAs was significantly correlated with their nearest gene. By inferring co-expression networks across our large dataset, we found that 39 lncRNAs are as major hubs in co-expression networks that respond to abiotic stress, and 18 appear to be derived from TEs. Conclusions Our results show that lncRNAs are enriched in total RNA samples, that most (65%) are derived from TEs, that at least 1077 are differentially expressed during abiotic stress, and that 39 are hubs in co-expression networks, including a small number that are evolutionary conserved. These results suggest that lncRNAs, including TE-lncRNAs, may play key regulatory roles in moderating abiotic responses.
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Affiliation(s)
- Yuanda Lv
- Provincial Key Laboratory of Agrobiology, Institute of Crop Germplasm and Biotechnology, Jiangsu Academy of Agricultural Sciences, Nanjing, China.,Department of Ecology and Evolutionary, Biology, UC Irvine, Irvine, CA, USA
| | - Fengqin Hu
- Institute of Soil Science, Chinese Academy of Sciences, Nanjing, China
| | - Yongfeng Zhou
- Department of Ecology and Evolutionary, Biology, UC Irvine, Irvine, CA, USA
| | - Feilong Wu
- Department of Civil and Environmental, Engineering, UC Irvine, Irvine, CA, USA
| | - Brandon S Gaut
- Department of Ecology and Evolutionary, Biology, UC Irvine, Irvine, CA, USA.
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16
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Legrand S, Caron T, Maumus F, Schvartzman S, Quadrana L, Durand E, Gallina S, Pauwels M, Mazoyer C, Huyghe L, Colot V, Hanikenne M, Castric V. Differential retention of transposable element-derived sequences in outcrossing Arabidopsis genomes. Mob DNA 2019; 10:30. [PMID: 31346350 PMCID: PMC6636163 DOI: 10.1186/s13100-019-0171-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2019] [Accepted: 06/28/2019] [Indexed: 12/20/2022] Open
Abstract
Background Transposable elements (TEs) are genomic parasites with major impacts on host genome architecture and host adaptation. A proper evaluation of their evolutionary significance has been hampered by the paucity of short scale phylogenetic comparisons between closely related species. Here, we characterized the dynamics of TE accumulation at the micro-evolutionary scale by comparing two closely related plant species, Arabidopsis lyrata and A. halleri. Results Joint genome annotation in these two outcrossing species confirmed that both contain two distinct populations of TEs with either 'recent' or 'old' insertion histories. Identification of rare segregating insertions suggests that diverse TE families contribute to the ongoing dynamics of TE accumulation in the two species. Orthologous TE fragments (i.e. those that have been maintained in both species), tend to be located closer to genes than those that are retained in one species only. Compared to non-orthologous TE insertions, those that are orthologous tend to produce fewer short interfering RNAs, are less heavily methylated when found within or adjacent to genes and these tend to have lower expression levels. These findings suggest that long-term retention of TE insertions reflects their frequent acquisition of adaptive roles and/or the deleterious effects of removing nearly neutral TE insertions when they are close to genes. Conclusion Our results indicate a rapid evolutionary dynamics of the TE landscape in these two outcrossing species, with an important input of a diverse set of new insertions with variable propensity to resist deletion.
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Affiliation(s)
- Sylvain Legrand
- 1Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Thibault Caron
- 1Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Florian Maumus
- 2URGI, INRA, Université Paris-Saclay, 78026 Versailles, France
| | - Sol Schvartzman
- 3InBioS - PhytoSystems, Functional Genomics and Plant Molecular Imaging, University of Liège, 4000 Liège, Belgium
| | - Leandro Quadrana
- 4IBENS, Département de Biologie, Ecole Normale Supérieure, CNRS, Inserm, PSL Research University, F-75005 Paris, France
| | - Eléonore Durand
- 1Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Sophie Gallina
- 1Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Maxime Pauwels
- 1Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Clément Mazoyer
- 1Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Lucie Huyghe
- 1Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
| | - Vincent Colot
- 4IBENS, Département de Biologie, Ecole Normale Supérieure, CNRS, Inserm, PSL Research University, F-75005 Paris, France
| | - Marc Hanikenne
- 3InBioS - PhytoSystems, Functional Genomics and Plant Molecular Imaging, University of Liège, 4000 Liège, Belgium
| | - Vincent Castric
- 1Univ. Lille, CNRS, UMR 8198 - Evo-Eco-Paleo, F-59000 Lille, France
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17
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Sanchez DH, Gaubert H, Yang W. Evidence of developmental escape from transcriptional gene silencing in MESSI retrotransposons. THE NEW PHYTOLOGIST 2019; 223:950-964. [PMID: 31063594 DOI: 10.1111/nph.15896] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Accepted: 03/12/2019] [Indexed: 05/04/2023]
Abstract
Transposable elements (TEs) are ubiquitous genomic features. 'Copy-and-paste' long-terminal-repeat (LTR) retrotransposons have been particularly successful during evolution of the plant kingdom, representing a substantial proportion of genomes. For survival in copious numbers, these TEs may have evolved replicative mobilization strategies that circumvented hosts' epigenetic silencing. Stressful circumstances are known to trigger the majority of known mobilizing plant retrotransposons, leading to the idea that most are activated by environmental signals. However, previous research revealed that plant developmental programs include steps of silencing relaxation, suggesting that developmental signals may also be of importance for thriving parasitic elements. Here, we uncover an unusual family of giant LTR retrotransposons from the Solanum clade, named MESSI, with transcriptional competence in shoot apical meristems of tomato. Despite being recognized and targeted by the host epigenetic surveillance, this family is activated in specific meristematic areas fundamental for plant shoot development, which are involved in meristem formation and maintenance. Our work provides initial evidence that some retrotransposons may evolve developmentally associated escape strategies to overcome transcriptional gene silencing in vegetative tissues contributing to the host's next generation. This implies that not only environmental but also developmental signals could be exploited by selfish elements for survival within the plant kingdom.
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Affiliation(s)
- Diego H Sanchez
- The Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR, UK
| | - Hervé Gaubert
- The Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR, UK
| | - Weibing Yang
- The Sainsbury Laboratory, University of Cambridge, 47 Bateman Street, Cambridge, CB2 1LR, UK
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18
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Press MO, Hall AN, Morton EA, Queitsch C. Substitutions Are Boring: Some Arguments about Parallel Mutations and High Mutation Rates. Trends Genet 2019; 35:253-264. [PMID: 30797597 PMCID: PMC6435258 DOI: 10.1016/j.tig.2019.01.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 12/20/2018] [Accepted: 01/14/2019] [Indexed: 12/31/2022]
Abstract
Extant genomes are largely shaped by global transposition, copy-number fluctuation, and rearrangement of DNA sequences rather than by substitutions of single nucleotides. Although many of these large-scale mutations have low probabilities and are unlikely to repeat, others are recurrent or predictable in their effects, leading to stereotyped genome architectures and genetic variation in both eukaryotes and prokaryotes. Such recurrent, parallel mutation modes can profoundly shape the paths taken by evolution and undermine common models of evolutionary genetics. Similar patterns are also evident at the smaller scales of individual genes or short sequences. The scale and extent of this 'non-substitution' variation has recently come into focus through the advent of new genomic technologies; however, it is still not widely considered in genotype-phenotype association studies. In this review we identify common features of these disparate mutational phenomena and comment on the importance and interpretation of these mutational patterns.
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Affiliation(s)
| | - Ashley N Hall
- Department of Genome Sciences, University of Washington, Seattle, WA 91895, USA; Department of Molecular and Cellular Biology, University of Washington, Seattle, WA 91895, USA
| | - Elizabeth A Morton
- Department of Genome Sciences, University of Washington, Seattle, WA 91895, USA
| | - Christine Queitsch
- Department of Genome Sciences, University of Washington, Seattle, WA 91895, USA.
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19
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Choi JY, Purugganan MD. Evolutionary Epigenomics of Retrotransposon-Mediated Methylation Spreading in Rice. Mol Biol Evol 2019; 35:365-382. [PMID: 29126199 PMCID: PMC5850837 DOI: 10.1093/molbev/msx284] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Plant genomes contain numerous transposable elements (TEs), and many hypotheses on the evolutionary drivers that restrict TE activity have been postulated. Few models, however, have focused on the evolutionary epigenomic interaction between the plant host and its TE. The host genome recruits epigenetic factors, such as methylation, to silence TEs but methylation can spread beyond the TE sequence and influence the expression of nearby host genes. In this study, we investigated this epigenetic trade-off between TE and proximal host gene silencing by studying the epigenomic regulation of repressing long terminal repeat (LTR) retrotransposons (RTs) in Oryza sativa. Results showed significant evidence of methylation spreading originating from the LTR-RT sequences, and the extent of spreading was dependent on five factors: 1) LTR-RT family, 2) time since the LTR-RT insertion, 3) recombination rate of the LTR-RT region, 4) level of LTR-RT sequence methylation, and 5) chromosomal location. Methylation spreading had negative effects by reducing host gene expression, but only on host genes with LTR-RT inserted in its introns. Our results also suggested high levels of LTR-RT methylation might have a role in suppressing TE-mediated deleterious ectopic recombination. In the end, despite the methylation spreading, no strong epigenetic trade-off was detected and majority of LTR-RT may have only minor epigenetic effects on nearby host genes.
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Affiliation(s)
- Jae Young Choi
- Department of Biology, Center for Genomics and Systems Biology, New York University, New York, NY
| | - Michael D Purugganan
- Department of Biology, Center for Genomics and Systems Biology, New York University, New York, NY.,Center for Genomics and Systems Biology, New York University Abu Dhabi, Saadiyat Island, Abu Dhabi, United Arab Emirates
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20
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Roessler K, Bousios A, Meca E, Gaut BS. Modeling Interactions between Transposable Elements and the Plant Epigenetic Response: A Surprising Reliance on Element Retention. Genome Biol Evol 2018; 10:803-815. [PMID: 29608716 PMCID: PMC5841382 DOI: 10.1093/gbe/evy043] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2018] [Indexed: 12/16/2022] Open
Abstract
Transposable elements (TEs) compose the majority of angiosperm DNA. Plants counteract TE activity by silencing them epigenetically. One form of epigenetic silencing requires 21-22 nt small interfering RNAs that act to degrade TE mRNA and may also trigger DNA methylation. DNA methylation is reinforced by a second mechanism, the RNA-dependent DNA methylation (RdDM) pathway. RdDM relies on 24 nt small interfering RNAs and ultimately establishes TEs in a quiescent state. These host factors interact at a systems level, but there have been no system level analyses of their interactions. Here, we define a deterministic model that represents the propagation of active TEs, aspects of the host response and the accumulation of silenced TEs. We describe general properties of the model and also fit it to biological data in order to explore two questions. The first is why two overlapping pathways are maintained, given that both are likely energetically expensive. Under our model, RdDM silenced TEs effectively even when the initiation of silencing was weak. This relationship implies that only a small amount of RNAi is needed to initiate TE silencing, but reinforcement by RdDM is necessary to efficiently counter TE propagation. Second, we investigated the reliance of the host response on rates of TE deletion. The model predicted that low levels of deletion lead to few active TEs, suggesting that silencing is most efficient when methylated TEs are retained in the genome, thereby providing one explanation for the large size of plant genomes.
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Affiliation(s)
- Kyria Roessler
- Department of Ecology and Evolutionary Biology, UC Irvine
| | | | - Esteban Meca
- Departamento de Agronomia, Universidad de Cordoba, Spain
| | - Brandon S Gaut
- Department of Ecology and Evolutionary Biology, UC Irvine
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21
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Song MJ, Schaack S. Evolutionary Conflict between Mobile DNA and Host Genomes. Am Nat 2018; 192:263-273. [DOI: 10.1086/698482] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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22
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Abstract
Transposable elements (TEs) are mobile genetic elements that were once perceived as merely selfish, but are now recognized as potent agents of adaptation. One way TEs contribute to genome evolution is through TE exaptation, a process whereby TEs, which usually persist by replicating in the genome, transform into novel host genes, which thereafter persist by conferring phenotypic benefits. Exapted TEs are known to contribute diverse and vital functions, and may facilitate punctuated equilibrium, yet we have little understanding about the process of TE exaptation. In order to facilitate our understanding of how TE coding sequences may become exapted, here we incorporate the findings of recent publications into a framework and six-step model.
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Affiliation(s)
- Zoé Joly-Lopez
- Center for Genomics and Systems Biology, Department of Biology, New York University, New York, NY 10003, USA
| | - Thomas E Bureau
- Department of Biology, McGill University, Montreal, QC H3A 1B1, Canada.
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23
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Qiu F, Ungerer MC. Genomic abundance and transcriptional activity of diverse gypsy and copia long terminal repeat retrotransposons in three wild sunflower species. BMC PLANT BIOLOGY 2018; 18:6. [PMID: 29304730 PMCID: PMC5755311 DOI: 10.1186/s12870-017-1223-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 12/21/2017] [Indexed: 05/02/2023]
Abstract
BACKGROUND Long terminal repeat (LTR) retrotransposons are highly abundant in plant genomes and require transcriptional activity for their proliferative mode of replication. These sequences exist in plant genomes as diverse sublineages within the main element superfamilies (i.e., gypsy and copia). While transcriptional activity of these elements is increasingly recognized as a regular attribute of plant transcriptomes, it is currently unknown the extent to which different sublineages of these elements are transcriptionally active both within and across species. In the current report, we utilize next generation sequencing methods to examine genomic copy number abundance of diverse LTR retrotransposon sublineages and their corresponding levels of transcriptional activity in three diploid wild sunflower species, Helianthus agrestis, H. carnosus and H. porteri. RESULTS The diploid sunflower species under investigation differ in genome size 2.75-fold, with 2C values of 22.93 for H. agrestis, 12.31 for H. carnosus and 8.33 for H. porteri. The same diverse gypsy and copia sublineages of LTR retrotransposons were identified across species, but with gypsy sequences consistently more abundant than copia and with global gypsy sequence abundance positively correlated with nuclear genome size. Transcriptional activity was detected for multiple copia and gypsy sequences, with significantly higher activity levels detected for copia versus gypsy. Interestingly, of 11 elements identified as transcriptionally active, 5 exhibited detectable expression in all three species and 3 exhibited detectable expression in two species. CONCLUSIONS Combined analyses of LTR retrotransposon genomic abundance and transcriptional activity across three sunflower species provides novel insights into genome size evolution and transposable element dynamics in this group. Despite considerable variation in nuclear genome size among species, relatively conserved patterns of LTR retrotransposon transcriptional activity were observed, with a highly overlapping set of copia and gypsy sequences observed to be transcriptionally active across species. A higher proportion of copia versus gypsy elements were found to be transcriptionally active and these sequences also were expressed at higher levels.
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Affiliation(s)
- Fan Qiu
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA.
| | - Mark C Ungerer
- Division of Biology, Kansas State University, Manhattan, KS, 66506, USA
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24
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25
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Hidalgo O, Pellicer J, Christenhusz M, Schneider H, Leitch AR, Leitch IJ. Is There an Upper Limit to Genome Size? TRENDS IN PLANT SCIENCE 2017; 22:567-573. [PMID: 28506667 DOI: 10.1016/j.tplants.2017.04.005] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Revised: 04/03/2017] [Accepted: 04/05/2017] [Indexed: 05/08/2023]
Abstract
At 50-fold the size of the human genome (3 Gb), the staggeringly huge genome of 147.3 Gb recently discovered in the fern Tmesipteris obliqua is comparable in size to those of the other plant and animal record-holders (i.e., Paris japonica, a flowering plant with a genome size of 148.8 Gb, and Protopterus aethiopicus, a lungfish with a genome of 130 Gb). The synthesis of available information on giant genomes suggests that the biological limit to genome size expansion in eukaryotes may have been reached. We propose several explanations for why the genomes of ferns, flowering plants, and lungfish, all of which have independently undergone dramatic increases in genome size through a variety of mechanisms, do not exceed 150 Gb.
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Affiliation(s)
| | | | | | - Harald Schneider
- Department of Life Sciences, Natural History Museum, London W7 5BD, UK; Xishuangbanna Tropical Botanical Garden, Centre for Integrative Conservation, Chinese Academy of Sciences, Menglun, Mengla, Yunnan, PR China
| | - Andrew R Leitch
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK
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26
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Zhou H, Kishima Y. Alternative plant host defense against transposon activities occurs at the post-translational stage. PLANT SIGNALING & BEHAVIOR 2017; 12:e1318238. [PMID: 28426280 PMCID: PMC5501231 DOI: 10.1080/15592324.2017.1318238] [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: 03/20/2017] [Revised: 04/06/2017] [Accepted: 04/07/2017] [Indexed: 06/07/2023]
Abstract
The Antirrhinum DNA transposon Tam3 uniquely demonstrates low temperature-dependent transposition (LTDT), so transposition does not occur at high temperatures. We previously showed that the detainment of Tam3 transposase (TPase) at the plasma membrane occurs when transposition is inactive, and that TPase is released at the permissive state of Tam3 transposition. LTDT of Tam3 is attributed to interactions between Tam3 and its host. In this addendum, we propose a model to explain the LTDT of Tam3, which is regarded as an equilibrium state reached between the host and parasite to maximize the fitness of both.
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Affiliation(s)
- Hua Zhou
- Laboratory of Plant Breeding, Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
| | - Yuji Kishima
- Laboratory of Plant Breeding, Research Faculty of Agriculture, Hokkaido University, Sapporo, Japan
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27
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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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28
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Baránek M, Čechová J, Kovacs T, Eichmeier A, Wang S, Raddová J, Nečas T, Ye X. Use of Combined MSAP and NGS Techniques to Identify Differentially Methylated Regions in Somaclones: A Case Study of Two Stable Somatic Wheat Mutants. PLoS One 2016; 11:e0165749. [PMID: 27792769 PMCID: PMC5085084 DOI: 10.1371/journal.pone.0165749] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 10/16/2016] [Indexed: 12/22/2022] Open
Abstract
The appearance of somaclonal variability induced by in vitro cultivation is relatively frequent and can, in some cases, provide a valuable source of new genetic variation for crop improvement. The cause of this phenomenon remains unknown; however, there are a number of reports suggesting that epigenetics, including DNA methylations, are an important factor. In addition to the non-heritable DNA methylation changes caused by transient and reversible stress-responsive gene regulation, recent evidence supports the existence of mitotically and meiotically inherited changes. The induction of phenotypes via stable DNA methylation changes has occasionally great economical value; however, very little is known about the genetic or molecular basis of these phenotypes. We used a novel approach consisting of a standard MSAP analysis followed by deep amplicon sequencing to better understand this phenomenon. Our models included two wheat genotypes, and their somaclones induced using in vitro cultivation with a changed heritable phenotype (shortened stem height and silenced high molecular weight glutenin). Using this novel procedure, we obtained information on the dissimilarity of DNA methylation landscapes between the standard cultivar and its respective somaclones, and we extracted the sequences and genome regions that were differentially methylated between subjects. Transposable elements were identified as the most likely factor for producing changes in somaclone properties. In summary, the novel approach of combining MSAP and NGS is relatively easy and widely applicable, which is a rather unique feature compared with the currently available techniques in the epigenetics field.
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Affiliation(s)
- Miroslav Baránek
- Mendeleum–Department of Genetics, Horticulture Faculty of Mendel University in Brno, Lednice, Czech Republic
- * E-mail:
| | - Jana Čechová
- Mendeleum–Department of Genetics, Horticulture Faculty of Mendel University in Brno, Lednice, Czech Republic
| | | | - Aleš Eichmeier
- Mendeleum–Department of Genetics, Horticulture Faculty of Mendel University in Brno, Lednice, Czech Republic
| | - Shunli Wang
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jana Raddová
- Mendeleum–Department of Genetics, Horticulture Faculty of Mendel University in Brno, Lednice, Czech Republic
| | - Tomáš Nečas
- Department of Fruit Growing, Horticulture Faculty of Mendel University in Brno, Lednice, Czech Republic
| | - Xingguo Ye
- Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
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