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Marand AP, Eveland AL, Kaufmann K, Springer NM. cis-Regulatory Elements in Plant Development, Adaptation, and Evolution. ANNUAL REVIEW OF PLANT BIOLOGY 2023; 74:111-137. [PMID: 36608347 PMCID: PMC9881396 DOI: 10.1146/annurev-arplant-070122-030236] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
cis-Regulatory elements encode the genomic blueprints that ensure the proper spatiotemporal patterning of gene expression necessary for appropriate development and responses to the environment. Accumulating evidence implicates changes to gene expression as a major source of phenotypic novelty in eukaryotes, including acute phenotypes such as disease and cancer in mammals. Moreover, genetic and epigenetic variation affecting cis-regulatory sequences over longer evolutionary timescales has become a recurring theme in studies of morphological divergence and local adaptation. Here, we discuss the functions of and methods used to identify various classes of cis-regulatory elements, as well as their role in plant development and response to the environment. We highlight opportunities to exploit cis-regulatory variants underlying plant development and environmental responses for crop improvement efforts. Although a comprehensive understanding of cis-regulatory mechanisms in plants has lagged behind that in animals, we showcase several breakthrough findings that have profoundly influenced plant biology and shaped the overall understanding of transcriptional regulation in eukaryotes.
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Affiliation(s)
| | | | - Kerstin Kaufmann
- Department for Plant Cell and Molecular Biology, Institute of Biology, Humboldt-Universität zu Berlin, Berlin, Germany;
| | - Nathan M Springer
- Department of Plant and Microbial Biology, University of Minnesota, Saint Paul, Minnesota, USA;
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2
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Oggenfuss U, Croll D. Recent transposable element bursts are associated with the proximity to genes in a fungal plant pathogen. PLoS Pathog 2023; 19:e1011130. [PMID: 36787337 PMCID: PMC9970103 DOI: 10.1371/journal.ppat.1011130] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Revised: 02/27/2023] [Accepted: 01/18/2023] [Indexed: 02/15/2023] Open
Abstract
The activity of transposable elements (TEs) contributes significantly to pathogen genome evolution. TEs often destabilize genome integrity but may also confer adaptive variation in pathogenicity or resistance traits. De-repression of epigenetically silenced TEs often initiates bursts of transposition activity that may be counteracted by purifying selection and genome defenses. However, how these forces interact to determine the expansion routes of TEs within a pathogen species remains largely unknown. Here, we analyzed a set of 19 telomere-to-telomere genomes of the fungal wheat pathogen Zymoseptoria tritici. Phylogenetic reconstruction and ancestral state estimates of individual TE families revealed that TEs have undergone distinct activation and repression periods resulting in highly uneven copy numbers between genomes of the same species. Most TEs are clustered in gene poor niches, indicating strong purifying selection against insertions near coding sequences, or as a consequence of insertion site preferences. TE families with high copy numbers have low sequence divergence and strong signatures of defense mechanisms (i.e., RIP). In contrast, small non-autonomous TEs (i.e., MITEs) are less impacted by defense mechanisms and are often located in close proximity to genes. Individual TE families have experienced multiple distinct burst events that generated many nearly identical copies. We found that a Copia element burst was initiated from recent copies inserted substantially closer to genes compared to older copies. Overall, TE bursts tended to initiate from copies in GC-rich niches that escaped inactivation by genomic defenses. Our work shows how specific genomic environments features provide triggers for TE proliferation in pathogen genomes.
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Affiliation(s)
- Ursula Oggenfuss
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
| | - Daniel Croll
- Laboratory of Evolutionary Genetics, Institute of Biology, University of Neuchâtel, Neuchâtel, Switzerland
- * E-mail:
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3
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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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4
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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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He J, Yu Z, Jiang J, Chen S, Fang W, Guan Z, Liao Y, Wang Z, Chen F, Wang H. An Eruption of LTR Retrotransposons in the Autopolyploid Genomes of Chrysanthemum nankingense (Asteraceae). PLANTS (BASEL, SWITZERLAND) 2022; 11:plants11030315. [PMID: 35161296 PMCID: PMC8839533 DOI: 10.3390/plants11030315] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 01/21/2022] [Accepted: 01/22/2022] [Indexed: 05/09/2023]
Abstract
Whole genome duplication, associated with the induction of widespread genetic changes, has played an important role in the evolution of many plant taxa. All extant angiosperm species have undergone at least one polyploidization event, forming either an auto- or allopolyploid organism. Compared with allopolyploidization, however, few studies have examined autopolyploidization, and few studies have focused on the response of genetic changes to autopolyploidy. In the present study, newly synthesized C. nankingense autotetraploids (Asteraceae) were employed to characterize the genome shock following autopolyploidization. Available evidence suggested that the genetic changes primarily involved the loss of old fragments and the gain of novel fragments, and some novel sequences were potential long terminal repeat (LTR) retrotransposons. As Ty1-copia and Ty3-gypsy elements represent the two main superfamilies of LTR retrotransposons, the dynamics of Ty1-copia and Ty3-gypsy were evaluated using RT-PCR, transcriptome sequencing, and LTR retrotransposon-based molecular marker techniques. Additionally, fluorescence in situ hybridization(FISH)results suggest that autopolyploidization might also be accompanied by perturbations of LTR retrotransposons, and emergence retrotransposon insertions might show more rapid divergence, resulting in diploid-like behaviour, potentially accelerating the evolutionary process among progenies. Our results strongly suggest a need to expand the current evolutionary framework to include a genetic dimension when seeking to understand genomic shock following autopolyploidization in Asteraceae.
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Inagaki S. Silencing and anti-silencing mechanisms that shape the epigenome in plants. Genes Genet Syst 2021; 96:217-228. [PMID: 34719532 DOI: 10.1266/ggs.21-00041] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Epigenome information mediates genome function and maintenance by regulating gene expression and chromatin organization. Because the epigenome pattern can change in response to internal and external environments, it may underlie an adaptive genome response that modulates phenotypes during development and in changing environments. Here I summarize recent progress in our understanding of how epigenome patterns are shaped and modulated by concerted actions of silencing and anti-silencing factors mainly in Arabidopsis thaliana. I discuss the dynamic nature of epigenome regulation, which is realized by cooperation and counteraction among silencing and anti-silencing factors, and how the dynamic epigenome mediates robust and plastic responses of plants to fluctuating environments.
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Affiliation(s)
- Soichi Inagaki
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo.,PRESTO, Japan Science and Technology Agency
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Minow MAA, Lukens L, Rossi V, Colasanti J. Patterns of stability and change in the maize genome: a case study of small RNA transcriptomes in two recombinant inbred lines and their progenitors. Genome 2021; 65:1-12. [PMID: 34597524 DOI: 10.1139/gen-2021-0040] [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: 11/22/2022]
Abstract
Small RNAs (sRNAs) are epigenetic regulators of eukaryotic genes and transposable elements (TEs). Diverse sRNA expression patterns exist within a species, but how this diversity arises is not well understood. To provide a window into the dynamics of maize sRNA patterning, sRNA and mRNA transcriptomes were examined in two related Zea mays recombinant inbred lines (RILs) and their inbred parents. Analysis of these RILs revealed that most clusters of sRNA expression retained the parental sRNA expression level. However, expression states that differ from the parental allele were also observed, predominantly reflecting decreases in sRNA expression. When RIL sRNA expression differed from the parental allele, the new state was frequently similar between the two RILs, and similar to the expression state found at the allele in the other parent. Novel sRNA expression patterns, distinct from those of either parent, were rare. Additionally, examination of sRNA expression over TEs revealed one TE family, Gyma, which showed consistent enrichment for RIL sRNA expression differences compared to those found in parental alleles. These findings provide insights into how sRNA silencing might evolve over generations and suggest that further investigation into the molecular nature of sRNA trans regulators is warranted.
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Affiliation(s)
- Mark A A Minow
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
| | - Lewis Lukens
- Plant Agriculture Department, University of Guelph, Guelph, Ontario, Canada
| | - Vincenzo Rossi
- Council for Agricultural Research and Economics, Research Centre for Cereal and Industrial Crops, I-24126 Bergamo, Italy
| | - Joseph Colasanti
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada
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Chalopin D, Clark LG, Wysocki WP, Park M, Duvall MR, Bennetzen JL. Integrated Genomic Analyses From Low-Depth Sequencing Help Resolve Phylogenetic Incongruence in the Bamboos (Poaceae: Bambusoideae). FRONTIERS IN PLANT SCIENCE 2021; 12:725728. [PMID: 34567039 PMCID: PMC8456298 DOI: 10.3389/fpls.2021.725728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Accepted: 08/13/2021] [Indexed: 06/13/2023]
Abstract
The bamboos (Bambusoideae, Poaceae) comprise a major grass lineage with a complex evolutionary history involving ancient hybridization and allopolyploidy. About 1700 described species are classified into three tribes, Olyreae (herbaceous bamboos), Bambuseae (tropical woody bamboos), and Arundinarieae (temperate woody bamboos). Nuclear analyses strongly support monophyly of the woody tribes, whereas plastome analyses strongly support paraphyly, with Bambuseae sister to Olyreae. Our objectives were to clarify the origin(s) of the woody bamboo tribes and resolve the nuclear vs. plastid conflict using genomic tools. For the first time, plastid and nuclear genomic information from the same bamboo species were combined in a single study. We sampled 51 species of bamboos representing the three tribes, estimated their genome sizes and generated low-depth sample sequence data, from which plastomes were assembled and nuclear repeats were analyzed. The distribution of repeat families was found to agree with nuclear gene phylogenies, but also provides novel insights into nuclear evolutionary history. We infer two early, independent hybridization events, one between an Olyreae ancestor and a woody ancestor giving rise to the two Bambuseae lineages, and another between two woody ancestors giving rise to the Arundinarieae. Retention of the Olyreae plastome associated with differential dominance of nuclear genomes and subsequent diploidization in some lineages explains the paraphyly observed in plastome phylogenetic estimations. We confirm ancient hybridization and allopolyploidy in the origins of the extant woody bamboo lineages and propose biased fractionation and diploidization as important factors in their evolution.
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Affiliation(s)
- Domitille Chalopin
- Department of Genetics, University of Georgia, Athens, GA, United States
| | - Lynn G. Clark
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, United States
| | - William P. Wysocki
- Center for Translational Data Science, University of Chicago, Chicago, IL, United States
| | - Minkyu Park
- Department of Genetics, University of Georgia, Athens, GA, United States
| | - Melvin R. Duvall
- Department of Biology and Institute for the Study of the Environment, Sustainability, and Energy, Northern Illinois University, DeKalb, IL, United States
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Linquist S, Fullerton B. Transposon dynamics and the epigenetic switch hypothesis. THEORETICAL MEDICINE AND BIOETHICS 2021; 42:137-154. [PMID: 34919173 PMCID: PMC8938347 DOI: 10.1007/s11017-021-09548-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 10/15/2021] [Indexed: 06/14/2023]
Abstract
The recent explosion of interest in epigenetics is often portrayed as the dawning of a scientific revolution that promises to transform biomedical science along with developmental and evolutionary biology. Much of this enthusiasm surrounds what we call the epigenetic switch hypothesis, which regards certain examples of epigenetic inheritance as an adaptive organismal response to environmental change. This interpretation overlooks an alternative explanation in terms of coevolutionary dynamics between parasitic transposons and the host genome. This raises a question about whether epigenetics researchers tend to overlook transposon dynamics more generally. To address this question, we surveyed a large sample of scientific publications on the topics of epigenetics and transposons over the past fifty years. We found that enthusiasm for epigenetics is often inversely related to interest in transposon dynamics across the four disciplines we examined. Most surprising was a declining interest in transposons within biomedical science and cellular and molecular biology over the past two decades. Also notable was a delayed and relatively muted enthusiasm for epigenetics within evolutionary biology. An analysis of scientific abstracts from the past twenty-five years further reveals systematic differences among disciplines in their uses of the term epigenetic, especially with respect to heritability commitments and functional interpretations. Taken together, these results paint a nuanced picture of the rise of epigenetics and the possible neglect of transposon dynamics, especially among biomedical scientists.
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Affiliation(s)
- Stefan Linquist
- Department of Philosophy, University of Guelph, Guelph, ON, Canada.
| | - Brady Fullerton
- Department of Philosophy, University of Guelph, Guelph, ON, Canada
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10
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Karlik E, Gurbuz O, Yildiz Y, Gozukirmizi N. Endogenous retrovirus HERV-K6 and HERV-K11 polymorphisms’ analyses in head and neck squamous cell carcinoma patients. Meta Gene 2021. [DOI: 10.1016/j.mgene.2021.100876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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11
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Thieme M, Roulin AC. Identification of Active Transposable Elements in Plants: The Mobilome-Seq Approach. Methods Mol Biol 2021; 2250:95-102. [PMID: 33900595 DOI: 10.1007/978-1-0716-1134-0_8] [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] [Indexed: 04/18/2023]
Abstract
Transposable elements (TEs) are the main component of eukaryotic genomes. Besides their impact on genome size, TEs are also functionally important as they can alter gene expression and influence phenotypic variation. In plants, most top-down studies focus on extremely clear phenotypes such as the shape or the color of individuals and do not explore fully the role of TEs in evolution. Assessing the impact of TEs in a more systematic manner, however, requires identifying active TEs to further study their impact on phenotypes. In this chapter, we describe an in planta approach that consists in activating TEs by interfering with pathways involved in their silencing. It enables to directly investigate the functional impact of single TE families at low cost.
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Affiliation(s)
- Michael Thieme
- Institute of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Anne C Roulin
- Institute of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland.
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12
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Fambrini M, Usai G, Vangelisti A, Mascagni F, Pugliesi C. The plastic genome: The impact of transposable elements on gene functionality and genomic structural variations. Genesis 2020; 58:e23399. [DOI: 10.1002/dvg.23399] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Revised: 11/07/2020] [Accepted: 11/10/2020] [Indexed: 12/15/2022]
Affiliation(s)
- Marco Fambrini
- Department of Agriculture, Food and Environment (DAFE) University of Pisa Pisa Italy
| | - Gabriele Usai
- Department of Agriculture, Food and Environment (DAFE) University of Pisa Pisa Italy
| | - Alberto Vangelisti
- Department of Agriculture, Food and Environment (DAFE) University of Pisa Pisa Italy
| | - Flavia Mascagni
- Department of Agriculture, Food and Environment (DAFE) University of Pisa Pisa Italy
| | - Claudio Pugliesi
- Department of Agriculture, Food and Environment (DAFE) University of Pisa Pisa Italy
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13
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Meile L, Peter J, Puccetti G, Alassimone J, McDonald BA, Sánchez-Vallet A. Chromatin Dynamics Contribute to the Spatiotemporal Expression Pattern of Virulence Genes in a Fungal Plant Pathogen. mBio 2020; 11:e02343-20. [PMID: 33024042 PMCID: PMC7542367 DOI: 10.1128/mbio.02343-20] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 09/15/2020] [Indexed: 12/14/2022] Open
Abstract
Dynamic changes in transcription profiles are key for the success of pathogens in colonizing their hosts. In many pathogens, genes associated with virulence, such as effector genes, are located in regions of the genome that are rich in transposable elements and heterochromatin. The contribution of chromatin modifications to gene expression in pathogens remains largely unknown. Using a combination of a reporter gene-based approach and chromatin immunoprecipitation, we show that the heterochromatic environment of effector genes in the fungal plant pathogen Zymoseptoria tritici is a key regulator of their specific spatiotemporal expression patterns. Enrichment in trimethylated lysine 27 of histone H3 dictates the repression of effector genes in the absence of the host. Chromatin decondensation during host colonization, featuring a reduction in this repressive modification, indicates a major role for epigenetics in effector gene induction. Our results illustrate that chromatin modifications triggered during host colonization determine the specific expression profile of effector genes at the cellular level and, hence, provide new insights into the regulation of virulence in fungal plant pathogens.IMPORTANCE Fungal plant pathogens possess a large repertoire of genes encoding putative effectors, which are crucial for infection. Many of these genes are expressed at low levels in the absence of the host but are strongly induced at specific stages of the infection. The mechanisms underlying this transcriptional reprogramming remain largely unknown. We investigated the role of the genomic environment and associated chromatin modifications of effector genes in controlling their expression pattern in the fungal wheat pathogen Zymoseptoria tritici Depending on their genomic location, effector genes are epigenetically repressed in the absence of the host and during the initial stages of infection. Derepression of effector genes occurs mainly during and after penetration of plant leaves and is associated with changes in histone modifications. Our work demonstrates the role of chromatin in shaping the expression of virulence components and, thereby, the interaction between fungal pathogens and their plant hosts.
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Affiliation(s)
- Lukas Meile
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Jules Peter
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Guido Puccetti
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Julien Alassimone
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Bruce A McDonald
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
| | - Andrea Sánchez-Vallet
- Plant Pathology, Institute of Integrative Biology, ETH Zürich, Zürich, Switzerland
- Centro de Biotecnología y Genómica de Plantas (CBGP, UPM-INIA), Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Pozuelo de Alarcón (Madrid), Spain
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14
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Shi T, Rahmani RS, Gugger PF, Wang M, Li H, Zhang Y, Li Z, Wang Q, Van de Peer Y, Marchal K, Chen J. Distinct Expression and Methylation Patterns for Genes with Different Fates following a Single Whole-Genome Duplication in Flowering Plants. Mol Biol Evol 2020; 37:2394-2413. [PMID: 32343808 PMCID: PMC7403625 DOI: 10.1093/molbev/msaa105] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
For most sequenced flowering plants, multiple whole-genome duplications (WGDs) are found. Duplicated genes following WGD often have different fates that can quickly disappear again, be retained for long(er) periods, or subsequently undergo small-scale duplications. However, how different expression, epigenetic regulation, and functional constraints are associated with these different gene fates following a WGD still requires further investigation due to successive WGDs in angiosperms complicating the gene trajectories. In this study, we investigate lotus (Nelumbo nucifera), an angiosperm with a single WGD during the K-pg boundary. Based on improved intraspecific-synteny identification by a chromosome-level assembly, transcriptome, and bisulfite sequencing, we explore not only the fundamental distinctions in genomic features, expression, and methylation patterns of genes with different fates after a WGD but also the factors that shape post-WGD expression divergence and expression bias between duplicates. We found that after a WGD genes that returned to single copies show the highest levels and breadth of expression, gene body methylation, and intron numbers, whereas the long-retained duplicates exhibit the highest degrees of protein-protein interactions and protein lengths and the lowest methylation in gene flanking regions. For those long-retained duplicate pairs, the degree of expression divergence correlates with their sequence divergence, degree in protein-protein interactions, and expression level, whereas their biases in expression level reflecting subgenome dominance are associated with the bias of subgenome fractionation. Overall, our study on the paleopolyploid nature of lotus highlights the impact of different functional constraints on gene fate and duplicate divergence following a single WGD in plant.
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Affiliation(s)
- Tao Shi
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
| | - Razgar Seyed Rahmani
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
| | - Paul F Gugger
- Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg, MD
| | - Muhua Wang
- School of Marine Sciences, Sun Yat-sen University, Guangzhou, China
| | - Hui Li
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yue Zhang
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhizhong Li
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qingfeng Wang
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
- Sino-African Joint Research Center, Chinese Academy of Sciences, Wuhan, China
| | - Yves Van de Peer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Centre for Plant Systems Biology, VIB, Ghent, Belgium
- Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Pretoria, South Africa
- College of Horticulture, Nanjing Agricultural University, Nanjing, China
| | - Kathleen Marchal
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
- Department of Information Technology, IDLab, IMEC, Ghent University, Ghent, Belgium
| | - Jinming Chen
- CAS Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, China
- Center of Conservation Biology, Core Botanical Gardens, Chinese Academy of Sciences, Wuhan, China
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15
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Lee HE, Huh JW, Kim HS. Bioinformatics Analysis of Evolution and Human Disease Related Transposable Element-Derived microRNAs. Life (Basel) 2020; 10:life10060095. [PMID: 32630504 PMCID: PMC7345915 DOI: 10.3390/life10060095] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 12/22/2022] Open
Abstract
Transposable element (TE) has the ability to insert into certain parts of the genome, and due to this event, it is possible for TEs to generate new factors and one of these factors are microRNAs (miRNA). miRNAs are non-coding RNAs made up of 19 to 24 nucleotides and numerous miRNAs are derived from TE. In this study, to support general knowledge on TE and miRNAs derived from TE, several bioinformatics tools and databases were used to analyze miRNAs derived from TE in two aspects: evolution and human disease. The distribution of TEs in diverse species presents that almost half of the genome is covered with TE in mammalians and less than a half in other vertebrates and invertebrates. Based on selected evolution-related miRNAs studies, a total of 51 miRNAs derived from TE were found and analyzed. For the human disease-related miRNAs, total of 34 miRNAs derived from TE were organized from the previous studies. In summary, abundant miRNAs derived from TE are found, however, the function of miRNAs derived from TE is not informed either. Therefore, this study provides theoretical understanding of miRNAs derived from TE by using various bioinformatics tools.
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Affiliation(s)
- Hee-Eun Lee
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (H.-E.L.); (J.-W.H.)
| | - Jae-Won Huh
- National Primate Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju 28116, Korea; (H.-E.L.); (J.-W.H.)
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon 34113, Korea
| | - Heui-Soo Kim
- Department of Biological Sciences, College of Natural Sciences, Pusan National University, Busan 46241, Korea
- Institute of Systems Biology, Pusan National University, Busan 46241, Korea
- Correspondence: ; Tel.: +82-51-510-2259; Fax: +82-51-581-2962
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16
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Ourari M, Coriton O, Martin G, Huteau V, Keller J, Ainouche ML, Amirouche R, Ainouche A. Screening diversity and distribution of Copia retrotransposons reveals a specific amplification of BARE1 elements in genomes of the polyploid Hordeum murinum complex. Genetica 2020; 148:109-123. [PMID: 32361835 DOI: 10.1007/s10709-020-00094-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Accepted: 04/24/2020] [Indexed: 10/24/2022]
Abstract
We explored diversity, distribution and evolutionary dynamics of Ty1-Copia retrotransposons in the genomes of the Hordeum murinum polyploid complex and related taxa. Phylogenetic and fluorescent in situ hybridization (FISH) analyses of reverse transcriptase sequences identified four Copia families in these genomes: the predominant BARE1 (including three groups or subfamilies, A, B and C), and the less represented RIRE1, IKYA and TAR-1. Within the BARE1 family, BARE1-A elements and a subgroup of BARE1-B elements (named B1) have proliferated in the allopolyploid members of the H. murinum complex (H. murinum and H. leporinum), and in their extant diploid progenitor, subsp. glaucum. Moreover, we found a specific amplification of BARE1-B elements within each Hordeum species surveyed. The low occurrence of RIRE1, IKYA and TAR-1 elements in the allopolyploid cytotypes suggests that they are either weakly represented or highly degenerated in their diploid progenitors. The results demonstrate that BARE1-A and BARE1-B1 Copia elements are particularly well represented in the genomes of the H. murinum complex and constitute its genomic hallmark. No BARE1-A and -B1 homologs were detected in the reference barley genome. The similar distribution of RT-Copia probes across chromosomes of diploid, tetraploid and hexaploid taxa of the murinum complex shows no evidence of proliferation following polyploidization.
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Affiliation(s)
- Malika Ourari
- Laboratory of Ecology and Environment, Department of Environment Biological Sciences, Faculty of Nature and Life Sciences, Université de Bejaia, Targa Ouzemmour, 06000, Bejaia, Algeria
| | - Olivier Coriton
- Institut National de Recherche en Agriculture, Alimentation et Environnement, UMR1349 INRAE-AgroCampus Ouest-Université de Rennes 1, Bât 301, INRA Centre de Bretagne-Normandie, BP 35327, 35653, Le Rheu Cedex, France
| | - Guillaume Martin
- CIRAD, UMR AGAP, 34398, Montpellier, France.,Université de Montpellier, AGAP, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Virginie Huteau
- Institut National de Recherche en Agriculture, Alimentation et Environnement, UMR1349 INRAE-AgroCampus Ouest-Université de Rennes 1, Bât 301, INRA Centre de Bretagne-Normandie, BP 35327, 35653, Le Rheu Cedex, France
| | - Jean Keller
- Université de Toulouse, LRSV, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, 31320, Auzeville-Tolosane, France
| | - Malika-Lily Ainouche
- Université de Rennes 1, UMR-CNRS 6553, EcoBio, Campus Scientifique de Beaulieu, Bât. 14A, 35042, Rennes Cedex, France
| | - Rachid Amirouche
- Université des Sciences et de la Technologie Houari Boumediene, Faculté des Sciences Biologiques, Lab. LBPO, USTHB, BP 32 El-Alia, Bab-Ezzouar, 16111, Alger, Algerie.
| | - Abdelkader Ainouche
- Université de Rennes 1, UMR-CNRS 6553, EcoBio, Campus Scientifique de Beaulieu, Bât. 14A, 35042, Rennes Cedex, France
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17
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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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18
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Anderson SN, Stitzer MC, Zhou P, Ross-Ibarra J, Hirsch CD, Springer NM. Dynamic Patterns of Transcript Abundance of Transposable Element Families in Maize. G3 (BETHESDA, MD.) 2019; 9:3673-3682. [PMID: 31506319 PMCID: PMC6829137 DOI: 10.1534/g3.119.400431] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 09/08/2019] [Indexed: 12/21/2022]
Abstract
Transposable Elements (TEs) are mobile elements that contribute the majority of DNA sequences in the maize genome. Due to their repetitive nature, genomic studies of TEs are complicated by the difficulty of properly attributing multi-mapped short reads to specific genomic loci. Here, we utilize a method to attribute RNA-seq reads to TE families rather than particular loci in order to characterize transcript abundance for TE families in the maize genome. We applied this method to assess per-family expression of transposable elements in >800 published RNA-seq libraries representing a range of maize development, genotypes, and hybrids. While a relatively small proportion of TE families are transcribed, expression is highly dynamic with most families exhibiting tissue-specific expression. A large number of TE families were specifically detected in pollen and endosperm, consistent with reproductive dynamics that maintain silencing of TEs in the germ line. We find that B73 transcript abundance is a poor predictor of TE expression in other genotypes and that transcript levels can differ even for shared TEs. Finally, by assessing recombinant inbred line and hybrid transcriptomes, complex patterns of TE transcript abundance across genotypes emerged. Taken together, this study reveals a dynamic contribution of TEs to maize transcriptomes.
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Affiliation(s)
| | - Michelle C Stitzer
- Department of Evolution and Ecology and Center for Population Biology and
| | - Peng Zhou
- Department of Plant and Microbial Biology and
| | - Jeffrey Ross-Ibarra
- Department of Evolution and Ecology and Center for Population Biology and
- Genome Center, University of California, Davis, California 95616
| | - Cory D Hirsch
- Department of Plant Pathology, University of Minnesota, St. Paul, Minnesota 55108, and
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19
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Gao L, Yang G, Li Y, Fan N, Li H, Zhang M, Xu R, Zhang M, Zhao A, Ni Z, Zhang Y. Fine mapping and candidate gene analysis of a QTL associated with leaf rolling index on chromosome 4 of maize (Zea mays L.). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2019; 132:3047-3062. [PMID: 31399756 DOI: 10.1007/s00122-019-03405-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Accepted: 07/21/2019] [Indexed: 05/19/2023]
Abstract
One QTL qLRI4 controlling leaf rolling index on chromosome 4 was finely mapped, and ZmOCL5, a member of the HD-Zip class IV genes, is likely a candidate. Leaf rolling is an important agronomic trait related to plant architecture that can change the light condition and photosynthetic efficiency of the population. Here, we isolated one EMS-induced mutant in Chang7-2 background with extreme abaxial rolling leaf, named abrl1. Histological analysis showed that the increased number and area of bulliform cells may contribute to abaxial rolling leaf in abrl1. The F2 and F2:3 populations derived from Wu9086 with flat leaves and abrl1 were developed to map abrl1. Non-Mendelian segregation of phenotypic variation was observed in these populations and five genomic regions controlling the leaf rolling index (LRI) were identified, which could be due to the phenotypic difference between Chang7-2 and Wu9086. Moreover, one major QTL qLRI4 on chromosome 4 was further validated and finely mapped to a genetic interval between InDel13 and InDel10, with a physical distance of approximately 277 kb using NIL populations, among which one 602-bp insertion was identified in the promoter region of HD-Zip class IV gene Zm00001d049443 (named as ZmOCL5) of abrl1 compared with wild-type Chang7-2. Remarkably, the 602-bp InDel was associated with LRI in an F2 population developed by crossing abrl1 mutant and its wild-type. In addition, the 602-bp insertion increased ZmOCL5 promoter activity and expression. Haplotype analysis demonstrated that the 602-bp insertion was a rare mutation event. Taken together, we propose that the rolled leaf in the abrl1 mutant may be partially attributed to the 602-bp insertion, which may be an attractive target for the genetic improvement of LRI in maize.
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Affiliation(s)
- Lulu Gao
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
- National Plant Gene Research Centre, Beijing, 100193, China
| | - Guanghui Yang
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
- National Plant Gene Research Centre, Beijing, 100193, China
| | - Yufeng Li
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
- National Plant Gene Research Centre, Beijing, 100193, China
| | - Nannan Fan
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
- National Maize Improvement Centre of China, China Agricultural University, Beijing, China
| | - Hongjian Li
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
- National Plant Gene Research Centre, Beijing, 100193, China
| | - Ming Zhang
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
- National Plant Gene Research Centre, Beijing, 100193, China
| | - Ruibin Xu
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
- National Plant Gene Research Centre, Beijing, 100193, China
| | - Mingyi Zhang
- Dryland Agricultural Research Centre, Shanxi Academy of Agricultural Sciences, Taiyuan, 030031, China
| | - Aiju Zhao
- Institute of Cereal and Oil Crops, Hebei Academy of Agriculture and Forestry Sciences, Hebei Crop Genetic Breeding Laboratory, Shijiazhuang, 050035, China
| | - Zhongfu Ni
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
- National Plant Gene Research Centre, Beijing, 100193, China
| | - Yirong Zhang
- State Key Laboratory for Agrobiotechnology and Key Laboratory of Crop Heterosis and Utilization, Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China.
- National Maize Improvement Centre of China, China Agricultural University, Beijing, China.
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20
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Noshay JM, Anderson SN, Zhou P, Ji L, Ricci W, Lu Z, Stitzer MC, Crisp PA, Hirsch CN, Zhang X, Schmitz RJ, Springer NM. Monitoring the interplay between transposable element families and DNA methylation in maize. PLoS Genet 2019; 15:e1008291. [PMID: 31498837 PMCID: PMC6752859 DOI: 10.1371/journal.pgen.1008291] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Revised: 09/19/2019] [Accepted: 07/05/2019] [Indexed: 12/15/2022] Open
Abstract
DNA methylation and epigenetic silencing play important roles in the regulation of transposable elements (TEs) in many eukaryotic genomes. A majority of the maize genome is derived from TEs that can be classified into different orders and families based on their mechanism of transposition and sequence similarity, respectively. TEs themselves are highly methylated and it can be tempting to view them as a single uniform group. However, the analysis of DNA methylation profiles in flanking regions provides evidence for distinct groups of chromatin properties at different TE families. These differences among TE families are reproducible in different tissues and different inbred lines. TE families with varying levels of DNA methylation in flanking regions also show distinct patterns of chromatin accessibility and modifications within the TEs. The differences in the patterns of DNA methylation flanking TE families arise from a combination of non-random insertion preferences of TE families, changes in DNA methylation triggered by the insertion of the TE and subsequent selection pressure. A set of nearly 70,000 TE polymorphisms among four assembled maize genomes were used to monitor the level of DNA methylation at haplotypes with and without the TE insertions. In many cases, TE families with high levels of DNA methylation in flanking sequence are enriched for insertions into highly methylated regions. The majority of the >2,500 TE insertions into unmethylated regions result in changes in DNA methylation in haplotypes with the TE, suggesting the widespread potential for TE insertions to condition altered methylation in conserved regions of the genome. This study highlights the interplay between TEs and the methylome of a major crop species.
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Affiliation(s)
- Jaclyn M. Noshay
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul MN, United States of America
| | - Sarah N. Anderson
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul MN, United States of America
| | - Peng Zhou
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul MN, United States of America
| | - Lexiang Ji
- Institute of Bioinformatics, University of Georgia, Athens GA, United States of America
| | - William Ricci
- Department of Plant Biology, University of Georgia, Athens GA, United States of America
| | - Zefu Lu
- Department of Genetics, University of Georgia, Athens GA, United States of America
| | - Michelle C. Stitzer
- Department of Plant Sciences, University of California Davis, Davis CA, United States of America
| | - Peter A. Crisp
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul MN, United States of America
| | - Candice N. Hirsch
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul MN, United States of America
| | - Xiaoyu Zhang
- Department of Plant Biology, University of Georgia, Athens GA, United States of America
| | - Robert J. Schmitz
- Department of Genetics, University of Georgia, Athens GA, United States of America
| | - Nathan M. Springer
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul MN, United States of America
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21
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Bayless AM, Zapotocny RW, Han S, Grunwald DJ, Amundson KK, Bent AF. The rhg1-a ( Rhg1 low-copy) nematode resistance source harbors a copia-family retrotransposon within the Rhg1-encoded α-SNAP gene. PLANT DIRECT 2019; 3:e00164. [PMID: 31468029 PMCID: PMC6712407 DOI: 10.1002/pld3.164] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Revised: 07/13/2019] [Accepted: 08/02/2019] [Indexed: 05/14/2023]
Abstract
Soybean growers widely use the Resistance to Heterodera glycines 1 (Rhg1) locus to reduce yield losses caused by soybean cyst nematode (SCN). Rhg1 is a tandemly repeated four gene block. Two classes of SCN resistance-conferring Rhg1 haplotypes are recognized: rhg1-a ("Peking-type," low-copy number, three or fewer Rhg1 repeats) and rhg1-b ("PI 88788-type," high-copy number, four or more Rhg1 repeats). The rhg1-a and rhg1-b haplotypes encode α-SNAP (alpha-Soluble NSF Attachment Protein) variants α-SNAP Rhg1 LC and α-SNAP Rhg1 HC, respectively, with differing atypical C-terminal domains, that contribute to SCN resistance. Here we report that rhg1-a soybean accessions harbor a copia retrotransposon within their Rhg1 Glyma.18G022500 (α-SNAP-encoding) gene. We termed this retrotransposon "RAC," for Rhg1 alpha-SNAP copia. Soybean carries multiple RAC-like retrotransposon sequences. The Rhg1 RAC insertion is in the Glyma.18G022500 genes of all true rhg1-a haplotypes we tested and was not detected in any examined rhg1-b or Rhg1WT (single-copy) soybeans. RAC is an intact element residing within intron 1, anti-sense to the rhg1-a α-SNAP open reading frame. RAC has intrinsic promoter activities, but overt impacts of RAC on transgenic α-SNAP Rhg1 LC mRNA and protein abundance were not detected. From the native rhg1-a RAC+ genomic context, elevated α-SNAP Rhg1 LC protein abundance was observed in syncytium cells, as was previously observed for α-SNAP Rhg1 HC (whose rhg1-b does not carry RAC). Using a SoySNP50K SNP corresponding with RAC presence, just ~42% of USDA accessions bearing previously identified rhg1-a SoySNP50K SNP signatures harbor the RAC insertion. Subsequent analysis of several of these putative rhg1-a accessions lacking RAC revealed that none encoded α-SNAPRhg1LC, and thus, they are not rhg1-a. rhg1-a haplotypes are of rising interest, with Rhg4, for combating SCN populations that exhibit increased virulence against the widely used rhg1-b resistance. The present study reveals another unexpected structural feature of many Rhg1 loci, and a selectable feature that is predictive of rhg1-a haplotypes.
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Affiliation(s)
- Adam M. Bayless
- Department of Plant PathologyUniversity of Wisconsin – MadisonMadisonWIUSA
| | - Ryan W. Zapotocny
- Department of Plant PathologyUniversity of Wisconsin – MadisonMadisonWIUSA
| | - Shaojie Han
- Department of Plant PathologyUniversity of Wisconsin – MadisonMadisonWIUSA
| | | | - Kaela K. Amundson
- Department of Plant PathologyUniversity of Wisconsin – MadisonMadisonWIUSA
| | - Andrew F. Bent
- Department of Plant PathologyUniversity of Wisconsin – MadisonMadisonWIUSA
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22
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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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23
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Rogivue A, Choudhury RR, Zoller S, Joost S, Felber F, Kasser M, Parisod C, Gugerli F. Genome-wide variation in nucleotides and retrotransposons in alpine populations of Arabis alpina (Brassicaceae). Mol Ecol Resour 2019; 19:773-787. [PMID: 30636378 DOI: 10.1111/1755-0998.12991] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Revised: 12/14/2018] [Accepted: 12/17/2018] [Indexed: 02/01/2023]
Abstract
Advances in high-throughput sequencing have promoted the collection of reference genomes and genome-wide diversity. However, the assessment of genomic variation among populations has hitherto mainly been surveyed through single-nucleotide polymorphisms (SNPs) and largely ignored the often major fraction of genomes represented by transposable elements (TEs). Despite accumulating evidence supporting the evolutionary significance of TEs, comprehensive surveys remain scarce. Here, we sequenced the full genomes of 304 individuals of Arabis alpina sampled from four nearby natural populations to genotype SNPs as well as polymorphic long terminal repeat retrotransposons (polymorphic TEs; i.e., presence/absence of TE insertions at specific loci). We identified 291,396 SNPs and 20,548 polymorphic TEs, comparing their contributions to genomic diversity and divergence across populations. Few SNPs were shared among populations and overall showed high population-specific variation, whereas most polymorphic TEs segregated among populations. The genomic context of these two classes of variants further highlighted candidate adaptive loci having a putative impact on functional genes. In particular, 4.96% of the SNPs were identified as nonsynonymous or affecting start/stop codons. In contrast, 43% of the polymorphic TEs were present next to Arabis genes enriched in functional categories related to the regulation of reproduction and responses to biotic as well as abiotic stresses. This unprecedented data set, mapping variation gained from SNPs and complementary polymorphic TEs within and among populations, will serve as a rich resource for addressing microevolutionary processes shaping genome variation.
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Affiliation(s)
- Aude Rogivue
- WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
| | - Rimjhim R Choudhury
- University of Neuchâtel, Neuchâtel, Switzerland.,Institute of Plant Sciences, University of Berne, Bern, Switzerland
| | - Stefan Zoller
- Genetic Diversity Centre, ETH Zürich, Zürich, Switzerland
| | - Stéphane Joost
- Laboratory of Geographic Information Systems (LASIG), School of Architecture, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - François Felber
- University of Neuchâtel, Neuchâtel, Switzerland.,Musée et Jardins botaniques cantonaux, Lausanne, Switzerland
| | | | | | - Felix Gugerli
- WSL Swiss Federal Research Institute, Birmensdorf, Switzerland
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24
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Valencia JD, Girgis HZ. LtrDetector: A tool-suite for detecting long terminal repeat retrotransposons de-novo. BMC Genomics 2019; 20:450. [PMID: 31159720 PMCID: PMC6547461 DOI: 10.1186/s12864-019-5796-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2018] [Accepted: 05/14/2019] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Long terminal repeat retrotransposons are the most abundant transposons in plants. They play important roles in alternative splicing, recombination, gene regulation, and defense mechanisms. Large-scale sequencing projects for plant genomes are currently underway. Software tools are important for annotating long terminal repeat retrotransposons in these newly available genomes. However, the available tools are not very sensitive to known elements and perform inconsistently on different genomes. Some are hard to install or obsolete. They may struggle to process large plant genomes. None can be executed in parallel out of the box and very few have features to support visual review of new elements. To overcome these limitations, we developed LtrDetector, which uses techniques inspired by signal-processing. RESULTS We compared LtrDetector to LTR_Finder and LTRharvest, the two most successful predecessor tools, on six plant genomes. For each organism, we constructed a ground truth data set based on queries from a consensus sequence database. According to this evaluation, LtrDetector was the most sensitive tool, achieving 16-23% improvement in sensitivity over LTRharvest and 21% improvement over LTR_Finder. All three tools had low false positive rates, with LtrDetector achieving 98.2% precision, in between its two competitors. Overall, LtrDetector provides the best compromise between high sensitivity and low false positive rate while requiring moderate time and utilizing memory available on personal computers. CONCLUSIONS LtrDetector uses a novel methodology revolving around k-mer distributions, which allows it to produce high-quality results using relatively lightweight procedures. It is easy to install and use. It is not species specific, performing well using its default parameters on genomes of varying size and repeat content. It is automatically configured for parallel execution and runs efficiently on an ordinary personal computer. It includes a k-mer scores visualization tool to facilitate manual review of the identified elements. These features make LtrDetector an attractive tool for future annotation projects involving long terminal repeat retrotransposons.
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Affiliation(s)
- Joseph D Valencia
- The Bioinformatics Toolsmith Laboratory, Tandy School of Computer Science, University of Tulsa, 800 South Tucker Drive, Tulsa, 74104, OK, USA
| | - Hani Z Girgis
- The Bioinformatics Toolsmith Laboratory, Tandy School of Computer Science, University of Tulsa, 800 South Tucker Drive, Tulsa, 74104, OK, USA.
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Molecular basis of transitivity in plant RNA silencing. Mol Biol Rep 2019; 46:4645-4660. [DOI: 10.1007/s11033-019-04866-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Accepted: 05/09/2019] [Indexed: 12/11/2022]
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LINE-1 hypomethylation in human hepatocellular carcinomas correlates with shorter overall survival and CIMP phenotype. PLoS One 2019; 14:e0216374. [PMID: 31059558 PMCID: PMC6502450 DOI: 10.1371/journal.pone.0216374] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Accepted: 04/18/2019] [Indexed: 02/08/2023] Open
Abstract
Reactivation of interspersed repetitive sequences due to loss of methylation is associated with genomic instability, one of the hallmarks of cancer cells. LINE-1 hypomethylation is a surrogate marker for global methylation loss and is potentially a new diagnostic and prognostic biomarker in tumors. However, the correlation of LINE-1 hypomethylation with clinicopathological parameters and the CpG island methylator phenotype (CIMP) in patients with liver tumors is not yet well defined, particularly in Caucasians who show quite low rates of HCV/HBV infection and a higher incidence of liver steatosis. Therefore, quantitative DNA methylation analysis of LINE-1, RASSF1A, and CCND2 using pyrosequencing was performed in human hepatocellular carcinomas (HCC, n = 40), hepatocellular adenoma (HCA, n = 10), focal nodular hyperplasia (FNH, n = 5), and corresponding peritumoral liver tissues as well as healthy liver tissues (n = 5) from Caucasian patients. Methylation results were correlated with histopathological findings and clinical data. We found loss of LINE-1 DNA methylation only in HCC. It correlated significantly with poor survival (log rank test, p = 0.007). An inverse correlation was found for LINE-1 and RASSF1A DNA methylation levels (r2 = -0.47, p = 0.002). LINE-1 hypomethylation correlated with concurrent RASSF1/CCND2 hypermethylation (Fisher’s exact test, p = 0.02). Both LINE-1 hypomethylation and RASSF1A/CCND2 hypermethylation were not found in benign hepatocellular tumors (HCA and FNH). Our results show that LINE-1 hypomethylation and RASSF1A/CCND2 hypermethylation are epigenetic aberrations specific for the process of malignant liver transformation. In addition, LINE-1 hypomethylation might serve as a future predictive biomarker to identify HCC patients with unfavorable overall survival.
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Transposable elements are regulated by context-specific patterns of chromatin marks in mouse embryonic stem cells. Nat Commun 2019; 10:34. [PMID: 30604769 PMCID: PMC6318327 DOI: 10.1038/s41467-018-08006-y] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 12/11/2018] [Indexed: 01/18/2023] Open
Abstract
The majority of mammalian genomes are devoted to transposable elements (TEs). Whilst TEs are increasingly recognized for their important biological functions, they are a potential danger to genomic stability and are carefully regulated by the epigenetic system. However, the full complexity of this regulatory system is not understood. Here, using mouse embryonic stem cells, we show that TEs are suppressed by heterochromatic marks like H3K9me3, and are also labelled by all major types of chromatin modification in complex patterns, including bivalent activatory and repressive marks. We identified 29 epigenetic modifiers that significantly deregulated at least one type of TE. The loss of Setdb1, Ncor2, Rnf2, Kat5, Prmt5, Uhrf1, and Rrp8 caused widespread changes in TE expression and chromatin accessibility. These effects were context-specific, with different chromatin modifiers regulating the expression and chromatin accessibility of specific subsets of TEs. Our work reveals the complex patterns of epigenetic regulation of TEs. Transposable elements (TEs) fulfill essential but poorly understood roles in genome organization and gene expression control. Here the authors show that the regulation of TEs occurs through overlapping epigenetic mechanisms that control the expression and chromatin signatures at TEs.
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Pirogov SA, Maksimenko OG, Georgiev PG. Transposable Elements in the Evolution of Gene Regulatory Networks. RUSS J GENET+ 2019. [DOI: 10.1134/s1022795419010113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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29
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Pereira JF, Ryan PR. The role of transposable elements in the evolution of aluminium resistance in plants. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:41-54. [PMID: 30325439 DOI: 10.1093/jxb/ery357] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/02/2018] [Indexed: 05/20/2023]
Abstract
Aluminium (Al) toxicity can severely reduce root growth and consequently affect plant development and yield. A mechanism by which many species resist the toxic effects of Al relies on the efflux of organic anions (OAs) from the root apices via OA transporters. Several of the genes encoding these OA transporters contain transposable elements (TEs) in the coding sequences or in flanking regions. Some of the TE-induced mutations impact Al resistance by modifying the level and/or location of gene expression so that OA efflux from the roots is increased. The importance of genomic modifications for improving the adaptation of plants to acid soils has been raised previously, but the growing number of examples linking TEs with these changes requires highlighting. Here, we review the role of TEs in creating genetic modifications that enhance the adaptation of plants to acid soils by increasing the release of OAs from the root apices. We argue that TEs have been an important source of beneficial mutations that have co-opted OA transporter proteins with other functions to perform this role. These changes have occurred relatively recently in the evolution of many species and likely facilitated their expansion into regions with acidic soils.
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Affiliation(s)
| | - Peter R Ryan
- CSIRO Agriculture and Food, Canberra, ACT, Australia
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Banerjee A, Arnesen JA, Moser D, Motsa BB, Johnson SR, Hamberger B. Engineering modular diterpene biosynthetic pathways in Physcomitrella patens. PLANTA 2019; 249:221-233. [PMID: 30470899 DOI: 10.1007/s00425-018-3053-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 11/14/2018] [Indexed: 06/09/2023]
Abstract
Modular assembly and heterologous expression in the moss Physcomitrella patens of pairs of diterpene synthases results in accumulation of modern land plant diterpenoids. Physcomitrella patens is a representative of the ancient bryophyte plant lineage with a genome size of 511 Mb, dominant haploid life cycle and limited chemical and metabolic complexity. For these plants, exceptional capacity for genome editing through homologous recombination is met with recently demonstrated in vivo assembly of multiple heterologous DNA fragments. These traits earlier made P. patens an attractive choice as a biotechnological chassis for photosynthesis-driven production of recombinant peptides. The lack of diterpene gibberellic acid phytohormones in P. patens combined with the recent targeted disruption of the single bifunctional diterpene synthase yielded lines devoid of endogenous diterpenoid metabolites and well-suited for engineering of terpenoid production. Here, we mimicked the modular nature of diterpene biosynthetic pathways found in modern land plants by developing a flexible pipeline to install three combinations of class II and class I diterpene synthases in P. patens to access industrially relevant diterpene biomaterials. In addition to a well-established neutral locus for targeted integration, we also explored loci created by a class of Long Terminal Repeat Retrotransposon present at moderate number in the genome of P. patens. Assembly of the pathways and production of the enzymes from the neutral locus led to accumulation of diterpenes matching the reported activities in the angiosperm sources. In contrast, insights gained with the retrotransposon loci indicate their suitability for targeting, but reveal potentially inherent complications which may require adaptation of the experimental design.
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Affiliation(s)
- Aparajita Banerjee
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
- Wisconsin Energy Institute, 1552 University Ave, Madison, WI, 53726, USA
| | - Jonathan A Arnesen
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Daniel Moser
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
- Institute of Biochemistry, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Balindile B Motsa
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Sean R Johnson
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA
| | - Bjoern Hamberger
- Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, 48824, USA.
- Wisconsin Energy Institute, 1552 University Ave, Madison, WI, 53726, USA.
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Lu H, Cui X, Liu Z, Liu Y, Wang X, Zhou Z, Cai X, Zhang Z, Guo X, Hua J, Ma Z, Wang X, Zhang J, Zhang H, Liu F, Wang K. Discovery and annotation of a novel transposable element family in Gossypium. BMC PLANT BIOLOGY 2018; 18:307. [PMID: 30486783 PMCID: PMC6264596 DOI: 10.1186/s12870-018-1519-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 11/13/2018] [Indexed: 05/23/2023]
Abstract
BACKGROUND Fluorescence in situ hybridization (FISH) is an efficient cytogenetic technology to study chromosome structure. Transposable element (TE) is an important component in eukaryotic genomes and can provide insights in the structure and evolution of eukaryotic genomes. RESULTS A FISH probe derived from bacterial artificial chromosome (BAC) clone 299N22 generated striking signals on all 26 chromosomes of the cotton diploid A genome (AA, 2x=26) but very few on the diploid D genome (DD, 2x=26). All 26 chromosomes of the A sub genome (At) of tetraploid cotton (AADD, 2n=4x=52) also gave positive signals with this FISH probe, whereas very few signals were observed on the D sub genome (Dt). Sequencing and annotation of BAC clone 299N22, revealed a novel Ty3/gypsy transposon family, which was named as 'CICR'. This family is a significant contributor to size expansion in the A (sub) genome but not in the D (sub) genome. Further FISH analysis with the LTR of CICR as a probe revealed that CICR is lineage-specific, since massive repeats were found in A and B genomic groups, but not in C-G genomic groups within the Gossypium genus. Molecular evolutionary analysis of CICR suggested that tetraploid cottons evolved after silence of the transposon family 1-1.5 million years ago (Mya). Furthermore, A genomes are more homologous with B genomes, and the C, E, F, and G genomes likely diverged from a common ancestor prior to 3.5-4 Mya, the time when CICR appeared. The genomic variation caused by the insertion of CICR in the A (sub) genome may have played an important role in the speciation of organisms with A genomes. CONCLUSIONS The CICR family is highly repetitive in A and B genomes of Gossypium, but not amplified in the C-G genomes. The differential amount of CICR family in At and Dt will aid in partitioning sub genome sequences for chromosome assemblies during tetraploid genome sequencing and will act as a method for assessing the accuracy of tetraploid genomes by looking at the proportion of CICR elements in resulting pseudochromosome sequences. The timeline of the expansion of CICR family provides a new reference for cotton evolutionary analysis, while the impact on gene function caused by the insertion of CICR elements will be a target for further analysis of investigating phenotypic differences between A genome and D genome species.
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Affiliation(s)
- Hejun Lu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Science, Anyang, 455000 Henan China
- Gembloux Agro-Bio Tech, University of Liège, 5030 Gembloux, Belgium
| | - Xinglei Cui
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Science, Anyang, 455000 Henan China
| | - Zhen Liu
- Anyang Institute of Technology, Anyang, 455000 Henan China
| | - Yuling Liu
- Anyang Institute of Technology, Anyang, 455000 Henan China
| | - Xingxing Wang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Science, Anyang, 455000 Henan China
| | - Zhongli Zhou
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Science, Anyang, 455000 Henan China
| | - Xiaoyan Cai
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Science, Anyang, 455000 Henan China
| | - Zhenmei Zhang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Science, Anyang, 455000 Henan China
| | - Xinlei Guo
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Science, Anyang, 455000 Henan China
| | - Jinping Hua
- Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193 China
| | - Zhiying Ma
- Key Laboratory for Crop Germplasm Resources of Hebei province, Hebei Agricultural University, Baoding, 071000 Hebei China
| | - Xiyin Wang
- Center for Genomics and Computational Biology, North China University of Science and Technology, Tangshan, 063000 Hebei China
| | - Jinfa Zhang
- Department of Plant and Environmental Sciences, New Mexico State University, Las Cruces, 88003 USA
| | - Hong Zhang
- Department of Biological Sciences, Texas Tech University, Lubbock, 79409 USA
| | - Fang Liu
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Science, Anyang, 455000 Henan China
| | - Kunbo Wang
- State Key Laboratory of Cotton Biology, Institute of Cotton Research of Chinese Academy of Agricultural Science, Anyang, 455000 Henan China
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Kelleher ES, Azevedo RBR, Zheng Y. The Evolution of Small-RNA-Mediated Silencing of an Invading Transposable Element. Genome Biol Evol 2018; 10:3038-3057. [PMID: 30252073 PMCID: PMC6404463 DOI: 10.1093/gbe/evy218] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2018] [Indexed: 12/11/2022] Open
Abstract
Transposable elements (TEs) are genomic parasites that impose fitness costs on their
hosts by producing deleterious mutations and disrupting gametogenesis. Host genomes avoid
these costs by regulating TE activity, particularly in germline cells where new insertions
are heritable and TEs are exceptionally active. However, the capacity of different
TE-associated fitness costs to select for repression in the host, and the role of
selection in the evolution of TE regulation more generally remain controversial. In this
study, we use forward, individual-based simulations to examine the evolution of
small-RNA-mediated TE regulation, a conserved mechanism for TE repression that is employed
by both prokaryotes and eukaryotes. To design and parameterize a biologically realistic
model, we drew on an extensive survey of empirical studies of the transposition and
regulation of P-element DNA transposons in Drosophila
melanogaster. We observed that even under conservative assumptions, where
small-RNA-mediated regulation reduces transposition only, repression evolves rapidly and
adaptively after the genome is invaded by a new TE in simulated populations. We further
show that the spread of repressor alleles through simulated populations is greatly
enhanced by two additional TE-imposed fitness costs: dysgenic sterility and ectopic
recombination. Finally, we demonstrate that the adaptive mutation rate to repression is a
critical parameter that influences both the evolutionary trajectory of host repression and
the associated proliferation of TEs after invasion in simulated populations. Our findings
suggest that adaptive evolution of TE regulation may be stronger and more prevalent than
previously appreciated, and provide a framework for interpreting empirical data.
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Affiliation(s)
- Erin S Kelleher
- Department of Biology and Biochemistry, University of Houston, Houston
| | | | - Yichen Zheng
- Department of Biology and Biochemistry, University of Houston, Houston.,Biodiversitt und Klima Forschungszentrum, Senckenberg Gesellschaft fr Naturforschung, Frankfurt am Main, Germany.,Institute of Genetics, University of Cologne, 50674 Cologne, NRW, Germany
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Crescente JM, Zavallo D, Helguera M, Vanzetti LS. MITE Tracker: an accurate approach to identify miniature inverted-repeat transposable elements in large genomes. BMC Bioinformatics 2018; 19:348. [PMID: 30285604 PMCID: PMC6171319 DOI: 10.1186/s12859-018-2376-y] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Accepted: 09/18/2018] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Miniature inverted-repeat transposable elements (MITEs) are short, non-autonomous class II transposable elements present in a high number of conserved copies in eukaryote genomes. An accurate identification of these elements can help to shed light on the mechanisms controlling genome evolution and gene regulation. The structure and distribution of these elements are well-defined and therefore computational approaches can be used to identify MITEs sequences. RESULTS Here we describe MITE Tracker, a novel, open source software program that finds and classifies MITEs using an efficient alignment strategy to retrieve nearby inverted-repeat sequences from large genomes. This program groups them into high sequence homology families using a fast clustering algorithm and finally filters only those elements that were likely transposed from different genomic locations because of their low scoring flanking sequence alignment. CONCLUSIONS Many programs have been proposed to find MITEs hidden in genomes. However, none of them are able to process large-scale genomes such as that of bread wheat. Furthermore, in many cases the existing methods perform high false-positive rates (or miss rates). The rice genome was used as reference to compare MITE Tracker against known tools. Our method turned out to be the most reliable in our tests. Indeed, it revealed more known elements, presented the lowest false-positive number and was the only program able to run with the bread wheat genome as input. In wheat, MITE Tracker discovered 6013 MITE families and allowed the first structural exploration of MITEs in the complete bread wheat genome.
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Affiliation(s)
- Juan Manuel Crescente
- Grupo Biotecnología y Recursos Genéticos, EEA INTA Marcos Juárez, Ruta 12 km 3, 2580, Marcos Juárez, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
| | - Diego Zavallo
- Instituto de Biotecnología, CNIA, Instituto Nacional de Tecnología Agropecuaria (INTA) Castelar, Los Reseros y Nicolas Repeto, Hurlingham, Buenos Aires, Argentina
| | - Marcelo Helguera
- Grupo Biotecnología y Recursos Genéticos, EEA INTA Marcos Juárez, Ruta 12 km 3, 2580, Marcos Juárez, Argentina
| | - Leonardo Sebastián Vanzetti
- Grupo Biotecnología y Recursos Genéticos, EEA INTA Marcos Juárez, Ruta 12 km 3, 2580, Marcos Juárez, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina
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Transposable Elements in the Organization and Diversification of the Genome of Aegilops speltoides Tausch (Poaceae, Triticeae). Int J Genomics 2018; 2018:4373089. [PMID: 30356408 PMCID: PMC6178165 DOI: 10.1155/2018/4373089] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 08/19/2018] [Indexed: 12/31/2022] Open
Abstract
Repetitive DNA-specifically, transposable elements (TEs)-is a prevailing genomic fraction in cereals that underlies extensive genome reshuffling and intraspecific diversification in the wild. Although large amounts of data have been accumulated, the effect of TEs on the genome architecture and functioning is not fully understood. Here, plant genome organization was addressed by means of cloning and sequencing TE fragments of different types, which compose the largest portion of the Aegilops speltoides genome. Individual genotypes were analyzed cytogenetically using the cloned TE fragments as the DNA probes for fluorescence in situ hybridization (FISH). The obtained TE sequences of the Ty1-copia, Ty3-gypsy, LINE, and CACTA superfamilies showed the relatedness of the Ae. speltoides genome to the Triticeae tribe and similarities to evolutionarily distant species. A significant number of clones consisted of intercalated fragments of TEs of various types, in which Fatima (Ty3-gypsy) sequences predominated. At the chromosomal level, different TE clones demonstrated sequence-specific patterning, emphasizing the effect of the TE fraction on the Ae. speltoides genome architecture and intraspecific diversification. Altogether, the obtained data highlight the current species-specific organization and patterning of the mobile element fraction and point to ancient evolutionary events in the genome of Ae. speltoides.
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Birth and Death of LTR-Retrotransposons in Aegilops tauschii. Genetics 2018; 210:1039-1051. [PMID: 30158124 DOI: 10.1534/genetics.118.301198] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 08/20/2018] [Indexed: 11/18/2022] Open
Abstract
Long terminal repeat-retrotransposons (LTR-RTs) are a major component of all flowering plant genomes. To analyze the time dynamics of LTR-RTs, we modeled the insertion rates of the 35 most abundant LTR-RT families in the genome of Aegilops tauschii, one of the progenitors of wheat. Our model of insertion rate (birth) takes into account random variation in LTR divergence and the deletion rate (death) of LTR-RTs. Modeling the death rate is crucial because ignoring it would underestimate insertion rates in the distant past. We rejected the hypothesis of constancy of insertion rates for all 35 families and showed by simulations that our hypothesis test controlled the false-positive rate. LTR-RT insertions peaked from 0.064 to 2.39 MYA across the 35 families. Among other effects, the average age of elements within a family was negatively associated with recombination rate along a chromosome, with proximity to the closest gene, and weakly associated with the proximity to its 5' end. Elements within a family that were near genes colinear with genes in the genome of tetraploid emmer wheat tended to be younger than those near noncolinear genes. We discuss these associations in the context of genome evolution and stability of genome sizes in the tribe Triticeae. We demonstrate the general utility of our models by analyzing the two most abundant LTR-RT families in Arabidopsis lyrata, and show that these families differed in their insertion dynamics. Our estimation methods are available in the R package TE on CRAN.
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Shams I, Raskina O. Intraspecific and intraorganismal copy number dynamics of retrotransposons and tandem repeat in Aegilops speltoides Tausch (Poaceae, Triticeae). PROTOPLASMA 2018; 255:1023-1038. [PMID: 29374788 DOI: 10.1007/s00709-018-1212-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 01/14/2018] [Indexed: 06/07/2023]
Abstract
Transposable elements (TE) and tandem repeats (TR) compose the largest fraction of the plant genome. The abundance and repatterning of repetitive DNA underlie intrapopulation polymorphisms and intraspecific diversification; however, the dynamics of repetitive elements in ontogenesis is not fully understood. Here, we addressed the genotype-specific and tissue-specific abundances and dynamics of the Ty1-copia, Ty3-gypsy, and LINE retrotransposons and species-specific Spelt1 tandem repeat in wild diploid goatgrass, Aegilops speltoides Tausch. Copy numbers of TEs and TR were estimated by real-time quantitative PCR in vegetative and generative tissues in original plants from contrasting allopatric populations and artificial intraspecific hybrids. The results showed that between leaves and somatic spike tissues as well as in progressive microsporogenesis of individual genotypes, the copy numbers of three TEs correlatively oscillated between 2- to 4-fold and the TR copy numbers fluctuated by 18- to 440-fold. Inter-individual and intraorganismal TEs and TR copy number dynamics demonstrate large-scale parallelism with extensive chromosomal rearrangements that were detected using fluorescent in situ hybridization in parental and hybrid genotypes. The data obtained indicate that tissue-specific differences in the abundance and pattern of repetitive sequences emerge during cell proliferation and differentiation in ontogenesis and reflect the reorganization of individual genomes in changing environments, especially in small peripheral population(s) under the influence of rapid climatic changes.
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Affiliation(s)
- Imad Shams
- Institute of Evolution and Department of Evolutionary and Environmental Biology, University of Haifa, Aba-Hushi Avenue 199, 3498838, Haifa, Mount Carmel, Israel
| | - Olga Raskina
- Institute of Evolution and Department of Evolutionary and Environmental Biology, University of Haifa, Aba-Hushi Avenue 199, 3498838, Haifa, Mount Carmel, Israel.
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Distinguishing friends, foes, and freeloaders in giant genomes. Curr Opin Genet Dev 2018; 49:49-55. [DOI: 10.1016/j.gde.2018.02.013] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 02/23/2018] [Accepted: 02/26/2018] [Indexed: 12/11/2022]
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38
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Ma K, Sun L, Cheng T, Pan H, Wang J, Zhang Q. Epigenetic Variance, Performing Cooperative Structure with Genetics, Is Associated with Leaf Shape Traits in Widely Distributed Populations of Ornamental Tree Prunus mume. FRONTIERS IN PLANT SCIENCE 2018; 9:41. [PMID: 29441078 PMCID: PMC5797549 DOI: 10.3389/fpls.2018.00041] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2017] [Accepted: 01/09/2018] [Indexed: 05/23/2023]
Abstract
Increasing evidence shows that epigenetics plays an important role in phenotypic variance. However, little is known about epigenetic variation in the important ornamental tree Prunus mume. We used amplified fragment length polymorphism (AFLP) and methylation-sensitive amplified polymorphism (MSAP) techniques, and association analysis and sequencing to investigate epigenetic variation and its relationships with genetic variance, environment factors, and traits. By performing leaf sampling, the relative total methylation level (29.80%) was detected in 96 accessions of P. mume. And the relative hemi-methylation level (15.77%) was higher than the relative full methylation level (14.03%). The epigenetic diversity (I∗ = 0.575, h∗ = 0.393) was higher than the genetic diversity (I = 0.484, h = 0.319). The cultivated population displayed greater epigenetic diversity than the wild populations in both southwest and southeast China. We found that epigenetic variance and genetic variance, and environmental factors performed cooperative structures, respectively. In particular, leaf length, width and area were positively correlated with relative full methylation level and total methylation level, indicating that the DNA methylation level played a role in trait variation. In total, 203 AFLP and 423 MSAP associated markers were detected and 68 of them were sequenced. Homologous analysis and functional prediction suggested that the candidate marker-linked genes were essential for leaf morphology development and metabolism, implying that these markers play critical roles in the establishment of leaf length, width, area, and ratio of length to width.
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Affiliation(s)
- Kaifeng Ma
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Lidan Sun
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Tangren Cheng
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Huitang Pan
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Jia Wang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing, China
| | - Qixiang Zhang
- Beijing Key Laboratory of Ornamental Plants Germplasm Innovation and Molecular Breeding, National Engineering Research Center for Floriculture, Beijing Laboratory of Urban and Rural Ecological Environment, Key Laboratory of Genetics and Breeding in Forest Trees and Ornamental Plants of Ministry of Education, School of Landscape Architecture, Beijing Forestry University, Beijing, China
- Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Beijing Forestry University, Beijing, China
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Mager S, Ludewig U. Massive Loss of DNA Methylation in Nitrogen-, but Not in Phosphorus-Deficient Zea mays Roots Is Poorly Correlated With Gene Expression Differences. FRONTIERS IN PLANT SCIENCE 2018; 9:497. [PMID: 29725341 PMCID: PMC5917015 DOI: 10.3389/fpls.2018.00497] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 04/03/2018] [Indexed: 05/20/2023]
Abstract
DNA methylation in plants plays a role in transposon silencing, genome stability and gene expression regulation. Environmental factors alter the methylation pattern of DNA and recently nutrient stresses, such as phosphate starvation, were shown to alter DNA methylation. Furthermore, DNA methylation had been frequently addressed in plants with notably small genomes that are poor in transposons. Here, we compare part of the DNA methylome of nitrogen- and phosphorus-deficient maize roots by reduced representation sequencing and analyze their relationship with gene expression under prolonged stresses. Tremendous DNA methylation loss was encountered in maize under nitrogen-deficiency, but much less with phosphorus-deficiency. This occurred only in the symmetrical cytosine context, predominantly in CG context, but also in the CHG context. In contrast to other plants, differential methylation in the more flexible CHH context was essentially absent. In both deficiency conditions a similar number of differentially expressed genes were found and differentially methylated regions (DMRs) were predominantly identified in transposable elements (TEs). A minor fraction of such DMRs was associated with altered gene expression of nearby genes. Interestingly, although these TEs were mostly hypomethylated, they were associated with both up- or down regulated gene expression. Our results suggest a different methylome regulation in maize compared to rice and Arabidopsis upon nutrient deficiencies and point to highly nutrient- and species-specific dynamics of genomic DNA methylation. Description of Significance: DNA methylation suppresses transposons in plant genomes, but was also associated with other genome protective functions and gene expression regulation. Recently it was shown that DNA methylation dynamically responds to several abiotic and biotic environmental factors, but to a large instance, DNA methylation is also heritable. DNA methylation changes have also been reported under phosphorus starvation in rice and Arabidopsis, but its relation with other nutrients and its importance for individual gene expression remains unclear. Here, DNA methylation changes upon the deficiency of two major essential nutrients, nitrogen and phosphorus, were studied in parallel with gene expression responses in maize roots. We show context, nutrient- and species-specific patterns in the methylome, as well as its relation with the nutrient-deficiency transcriptome. While cases of differentially methylated regions in the vicinity of differentially expressed genes were apparent, both positive and negative roles on the gene expression were identified, irrespective of the context.
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Martinez G, Choudury SG, Slotkin RK. tRNA-derived small RNAs target transposable element transcripts. Nucleic Acids Res 2017; 45:5142-5152. [PMID: 28335016 PMCID: PMC5605234 DOI: 10.1093/nar/gkx103] [Citation(s) in RCA: 167] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Accepted: 02/06/2017] [Indexed: 12/19/2022] Open
Abstract
tRNA-derived RNA fragments (tRFs) are 18–26 nucleotide small RNAs that are not random degradation products, but are rather specifically cleaved from mature tRNA transcripts. Abundant in stressed or viral-infected cells, the function and potential targets of tRFs are not known. We identified that in the unstressed wild-type male gamete containing pollen of flowering plants, and analogous reproductive structure in non-flowering plant species, tRFs accumulate to high levels. In the reference plant Arabidopsis thaliana, tRFs are processed by Dicer-like 1 and incorporated into Argonaute1 (AGO1), akin to a microRNA. We utilized the fact that many plant small RNAs direct cleavage of their target transcripts to demonstrate that the tRF–AGO1 complex acts to specifically target and cleave endogenous transposable element (TE) mRNAs produced from transcriptionally active TEs. The data presented here demonstrate that tRFs are bona-fide regulatory microRNA-like small RNAs involved in the regulation of genome stability through the targeting of TE transcripts.
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Affiliation(s)
- German Martinez
- Department of Molecular Genetics and Center for RNA Biology, The Ohio State University, Columbus, 43210 OH, USA.,Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center of Plant Biology, 75007 Uppsala, Sweden
| | - Sarah G Choudury
- Department of Molecular Genetics and Center for RNA Biology, The Ohio State University, Columbus, 43210 OH, USA.,Molecular, Cellular and Developmental Biology Graduate Program, The Ohio State University, Columbus, 43210 OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, 43210 OH, USA
| | - R Keith Slotkin
- Department of Molecular Genetics and Center for RNA Biology, The Ohio State University, Columbus, 43210 OH, USA.,Center for RNA Biology, The Ohio State University, Columbus, 43210 OH, USA
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Reexamining the P-Element Invasion of Drosophila melanogaster Through the Lens of piRNA Silencing. Genetics 2017; 203:1513-31. [PMID: 27516614 DOI: 10.1534/genetics.115.184119] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2015] [Accepted: 05/25/2016] [Indexed: 11/18/2022] Open
Abstract
Transposable elements (TEs) are both important drivers of genome evolution and genetic parasites with potentially dramatic consequences for host fitness. The recent explosion of research on regulatory RNAs reveals that small RNA-mediated silencing is a conserved genetic mechanism through which hosts repress TE activity. The invasion of the Drosophila melanogaster genome by P elements, which happened on a historical timescale, represents an incomparable opportunity to understand how small RNA-mediated silencing of TEs evolves. Repression of P-element transposition emerged almost concurrently with its invasion. Recent studies suggest that this repression is implemented in part, and perhaps predominantly, by the Piwi-interacting RNA (piRNA) pathway, a small RNA-mediated silencing pathway that regulates TE activity in many metazoan germlines. In this review, I consider the P-element invasion from both a molecular and evolutionary genetic perspective, reconciling classic studies of P-element regulation with the new mechanistic framework provided by the piRNA pathway. I further explore the utility of the P-element invasion as an exemplar of the evolution of piRNA-mediated silencing. In light of the highly-conserved role for piRNAs in regulating TEs, discoveries from this system have taxonomically broad implications for the evolution of repression.
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Sharma RD, Bogaerts B, Goyal N. RDM16 and STA1 regulate differential usage of exon/intron in RNA directed DNA methylation pathway. Gene 2017; 609:62-67. [DOI: 10.1016/j.gene.2017.01.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/23/2016] [Accepted: 01/23/2017] [Indexed: 10/20/2022]
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Eichten SR, Stuart T, Srivastava A, Lister R, Borevitz JO. DNA methylation profiles of diverse Brachypodium distachyon align with underlying genetic diversity. Genome Res 2016; 26:1520-1531. [PMID: 27613611 PMCID: PMC5088594 DOI: 10.1101/gr.205468.116] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 08/25/2016] [Indexed: 12/13/2022]
Abstract
DNA methylation, a common modification of genomic DNA, is known to influence the expression of transposable elements as well as some genes. Although commonly viewed as an epigenetic mark, evidence has shown that underlying genetic variation, such as transposable element polymorphisms, often associate with differential DNA methylation states. To investigate the role of DNA methylation variation, transposable element polymorphism, and genomic diversity, whole-genome bisulfite sequencing was performed on genetically diverse lines of the model cereal Brachypodium distachyon. Although DNA methylation profiles are broadly similar, thousands of differentially methylated regions are observed between lines. An analysis of novel transposable element indel variation highlighted hundreds of new polymorphisms not seen in the reference sequence. DNA methylation and transposable element variation is correlated with the genome-wide amount of genetic variation present between samples. However, there was minimal evidence that novel transposon insertions or deletions are associated with nearby differential methylation. This study highlights unique relationships between genetic variation and DNA methylation variation within Brachypodium and provides a valuable map of DNA methylation across diverse resequenced accessions of this model cereal species.
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Affiliation(s)
- Steven R Eichten
- ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, Australia, 2601
| | - Tim Stuart
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Australia, 6009
| | - Akanksha Srivastava
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Australia, 6009
| | - Ryan Lister
- ARC Centre of Excellence in Plant Energy Biology, University of Western Australia, Perth, Australia, 6009
| | - Justin O Borevitz
- ARC Centre of Excellence in Plant Energy Biology, The Australian National University, Canberra, Australia, 2601
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45
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Santos FC, Guyot R, do Valle CB, Chiari L, Techio VH, Heslop-Harrison P, Vanzela ALL. Chromosomal distribution and evolution of abundant retrotransposons in plants: gypsy elements in diploid and polyploid Brachiaria forage grasses. Chromosome Res 2016; 23:571-82. [PMID: 26386563 DOI: 10.1007/s10577-015-9492-6] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Like other eukaryotes, the nuclear genome of plants consists of DNA with a small proportion of low-copy DNA (genes and regulatory sequences) and very abundant DNA sequence motifs that are repeated thousands up to millions of times in the genomes including transposable elements (TEs) and satellite DNA. Retrotransposons, one class of TEs, are sequences that amplify via an RNA intermediate and reinsert into the genome, are often the major fraction of a genome. Here, we put research on retrotransposons into the larger context of plant repetitive DNA and genome behaviour, showing features of genome evolution in a grass genus, Brachiaria, in relation to other plant species. We show the contrasting amplification of different retroelement fractions across the genome with characteristics for various families and domains. The genus Brachiaria includes both diploid and polyploid species, with similar chromosome types and chromosome basic numbers x = 6, 7, 8 and 9. The polyploids reproduce asexually and are apomictic, but there are also sexual species. Cytogenetic studies and flow cytometry indicate a large variation in DNA content (C-value), chromosome sizes and genome organization. In order to evaluate the role of transposable elements in the genome and karyotype organization of species of Brachiaria, we searched for sequences similar to conserved regions of TEs in RNAseq reads library produced in Brachiaria decumbens. Of the 9649 TE-like contigs, 4454 corresponded to LTR-retrotransposons, and of these, 79.5 % were similar to members of the gypsy superfamily. Sequences of conserved protein domains of gypsy were used to design primers for producing the probes. The probes were used in FISH against chromosomes of accesses of B. decumbens, Brachiaria brizantha, Brachiaria ruziziensis and Brachiaria humidicola. Probes showed hybridization signals predominantly in proximal regions, especially those for retrotransposons of the clades CRM and Athila, while elements of Del and Tat exhibited dispersed signals, in addition to those proximal signals. These results show that the proximal region of Brachiaria chromosomes is a hotspot for retrotransposon insertion, particularly for the gypsy family. The combination of high-throughput sequencing and a chromosome-centric cytogenetic approach allows the abundance, organization and nature of transposable elements to be characterized in unprecedented detail. By their amplification and dispersal, retrotransposons can affect gene expression; they can lead to rapid diversification of chromosomes between species and, hence, are useful for studies of genome evolution and speciation in the Brachiaria genus. Centromeric regions can be identified and mapped, and retrotransposon markers can also assisting breeders in the developing and exploiting interspecific hybrids.
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Affiliation(s)
- Fabíola Carvalho Santos
- Department of General Biology, Center of Biological Sciences, State University of Londrina, Londrina, 86057-970, Paraná State, Brazil
| | - Romain Guyot
- Institut de Recherche pour le Développement (IRD), UMR IPME, BP 64501, 34394, Montpellier Cedex, France
| | | | - Lucimara Chiari
- Embrapa Gado de Corte, 79106-550, Campo Grande, Mato Grosso do Sul State, Brazil
| | - Vânia Helena Techio
- Department of Biology, Federal University of Lavras, 37200-000, Lavras, Minas Gerais State, Brazil
| | | | - André Luís Laforga Vanzela
- Department of General Biology, Center of Biological Sciences, State University of Londrina, Londrina, 86057-970, Paraná State, Brazil.
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Li SF, Zhang GJ, Yuan JH, Deng CL, Gao WJ. Repetitive sequences and epigenetic modification: inseparable partners play important roles in the evolution of plant sex chromosomes. PLANTA 2016; 243:1083-95. [PMID: 26919983 DOI: 10.1007/s00425-016-2485-7] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2016] [Accepted: 02/07/2016] [Indexed: 05/03/2023]
Abstract
The present review discusses the roles of repetitive sequences played in plant sex chromosome evolution, and highlights epigenetic modification as potential mechanism of repetitive sequences involved in sex chromosome evolution. Sex determination in plants is mostly based on sex chromosomes. Classic theory proposes that sex chromosomes evolve from a specific pair of autosomes with emergence of a sex-determining gene(s). Subsequently, the newly formed sex chromosomes stop recombination in a small region around the sex-determining locus, and over time, the non-recombining region expands to almost all parts of the sex chromosomes. Accumulation of repetitive sequences, mostly transposable elements and tandem repeats, is a conspicuous feature of the non-recombining region of the Y chromosome, even in primitive one. Repetitive sequences may play multiple roles in sex chromosome evolution, such as triggering heterochromatization and causing recombination suppression, leading to structural and morphological differentiation of sex chromosomes, and promoting Y chromosome degeneration and X chromosome dosage compensation. In this article, we review the current status of this field, and based on preliminary evidence, we posit that repetitive sequences are involved in sex chromosome evolution probably via epigenetic modification, such as DNA and histone methylation, with small interfering RNAs as the mediator.
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Affiliation(s)
- Shu-Fen Li
- College of Life Sciences, Henan Normal University, Xinxiang, 453007, China
| | - Guo-Jun Zhang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, 453003, China
| | - Jin-Hong Yuan
- College of Life Sciences, Henan Normal University, Xinxiang, 453007, China
| | - Chuan-Liang Deng
- College of Life Sciences, Henan Normal University, Xinxiang, 453007, China
| | - Wu-Jun Gao
- College of Life Sciences, Henan Normal University, Xinxiang, 453007, China.
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47
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Fultz D, Choudury SG, Slotkin RK. Silencing of active transposable elements in plants. CURRENT OPINION IN PLANT BIOLOGY 2015; 27:67-76. [PMID: 26164237 DOI: 10.1016/j.pbi.2015.05.027] [Citation(s) in RCA: 98] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/20/2015] [Accepted: 05/22/2015] [Indexed: 05/04/2023]
Abstract
In plant genomes the vast majority of transposable elements (TEs) are found in a transcriptionally silenced state that is epigenetically propagated from generation to generation. Although the mechanism of this maintenance of silencing has been well studied, it is now clear that the pathways responsible for maintaining TEs in a silenced state differ from the pathways responsible for initially targeting the TE for silencing. Recently, attention in this field has focused on investigating the molecular mechanisms that initiate and establish TE silencing. Here we review the current models of how TEs are triggered for silencing, the data supporting each model, and the key future questions in this fast moving field.
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Affiliation(s)
- Dalen Fultz
- Department of Molecular Genetics, The Ohio State University, United States
| | - Sarah G Choudury
- Department of Molecular Genetics, The Ohio State University, United States
| | - R Keith Slotkin
- Department of Molecular Genetics, The Ohio State University, United States; Center for RNA Biology, The Ohio State University, United States.
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48
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Hoen DR, Hickey G, Bourque G, Casacuberta J, Cordaux R, Feschotte C, Fiston-Lavier AS, Hua-Van A, Hubley R, Kapusta A, Lerat E, Maumus F, Pollock DD, Quesneville H, Smit A, Wheeler TJ, Bureau TE, Blanchette M. A call for benchmarking transposable element annotation methods. Mob DNA 2015; 6:13. [PMID: 26244060 PMCID: PMC4524446 DOI: 10.1186/s13100-015-0044-6] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 07/22/2015] [Indexed: 12/31/2022] Open
Abstract
DNA derived from transposable elements (TEs) constitutes large parts of the genomes of complex eukaryotes, with major impacts not only on genomic research but also on how organisms evolve and function. Although a variety of methods and tools have been developed to detect and annotate TEs, there are as yet no standard benchmarks-that is, no standard way to measure or compare their accuracy. This lack of accuracy assessment calls into question conclusions from a wide range of research that depends explicitly or implicitly on TE annotation. In the absence of standard benchmarks, toolmakers are impeded in improving their tools, annotators cannot properly assess which tools might best suit their needs, and downstream researchers cannot judge how accuracy limitations might impact their studies. We therefore propose that the TE research community create and adopt standard TE annotation benchmarks, and we call for other researchers to join the authors in making this long-overdue effort a success.
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Affiliation(s)
- Douglas R Hoen
- School of Computer Science, McGill University, McConnell Engineering Bldg., Rm. 318, 3480 Rue University, Montréal, Québec H3A 0E9 Canada ; Department of Biology, McGill University, Stewart Biology Bldg., 1205 Ave. du Docteur-Penfield, Montréal, Québec H3A 1B1 Canada
| | - Glenn Hickey
- School of Computer Science, McGill University, McConnell Engineering Bldg., Rm. 318, 3480 Rue University, Montréal, Québec H3A 0E9 Canada ; McGill Centre for Bioinformatics, McGill University, Montréal, Québec Canada
| | - Guillaume Bourque
- Department of Human Genetics, McGill University, Montréal, Québec Canada ; McGill University and Génome Québec Innovation Center, Montréal, Québec Canada
| | - Josep Casacuberta
- Centre for Research in Agricultural Genomics CSIC-IRTA-UAB-UB, 08193 Barcelona, Spain
| | - Richard Cordaux
- Université de Poitiers, UMR CNRS 7267 Ecologie et Biologie des Interactions, Equipe Ecologie Evolution Symbiose, 5 Rue Albert Turpin, 86073 Poitiers Cedex 9, France
| | - Cédric Feschotte
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112 USA
| | - Anna-Sophie Fiston-Lavier
- Institut des Sciences de l'Evolution de Montpellier (ISE-M), Equipe Evolution, Vecteurs, Adaptation et Symbiose, UMR5554 CNRS-Université Montpellier, Montpellier, 34090 cedex 05 France
| | - Aurélie Hua-Van
- Laboratoire Evolution, Génomes, Comportement Ecologie, CNRS-Université Paris-Sud (UMR 9191)-IRD (UMR 247)-Université Paris-Saclay, F-91198 Gif-sur-Yvette, France
| | - Robert Hubley
- Institute for Systems Biology, 401 Terry Ave. N, Seattle, WA 98109 USA
| | - Aurélie Kapusta
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, UT 84112 USA
| | - Emmanuelle Lerat
- Laboratoire Biometrie et Biologie Evolutive, Universite Claude Bernard-Lyon 1, UMR-CNRS 5558-Bat. Mendel, 43 bd du 11 novembre 1918, 69622 Villeurbanne cedex, France
| | - Florian Maumus
- INRA, UR1164 URGI-Research Unit in Genomics-Info, INRA de Versailles-Grignon, Route de Saint-Cyr, Versailles, 78026 France
| | - David D Pollock
- University of Colorado School of Medicine, Aurora, CO 80045 USA
| | - Hadi Quesneville
- INRA, UR1164 URGI-Research Unit in Genomics-Info, INRA de Versailles-Grignon, Route de Saint-Cyr, Versailles, 78026 France
| | - Arian Smit
- Institute for Systems Biology, 401 Terry Ave. N, Seattle, WA 98109 USA
| | - Travis J Wheeler
- Department of Computer Science, University of Montana, Missoula, MT 59812 USA
| | - Thomas E Bureau
- Department of Biology, McGill University, Stewart Biology Bldg., 1205 Ave. du Docteur-Penfield, Montréal, Québec H3A 1B1 Canada
| | - Mathieu Blanchette
- School of Computer Science, McGill University, McConnell Engineering Bldg., Rm. 318, 3480 Rue University, Montréal, Québec H3A 0E9 Canada ; McGill Centre for Bioinformatics, McGill University, Montréal, Québec Canada
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Freeling M, Xu J, Woodhouse M, Lisch D. A Solution to the C-Value Paradox and the Function of Junk DNA: The Genome Balance Hypothesis. MOLECULAR PLANT 2015; 8:899-910. [PMID: 25743198 DOI: 10.1016/j.molp.2015.02.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 02/03/2015] [Accepted: 02/18/2015] [Indexed: 05/11/2023]
Abstract
The Genome Balance Hypothesis originated from a recent study that provided a mechanism for the phenomenon of genome dominance in ancient polyploids: unique 24nt RNA coverage near genes is greater in genes on the recessive subgenome irrespective of differences in gene expression. 24nt RNAs target transposons. Transposon position effects are now hypothesized to balance the expression of networked genes and provide spring-like tension between pericentromeric heterochromatin and microtubules. The balance (coordination) of gene expression and centromere movement is under selection. Our hypothesis states that this balance can be maintained by many or few transposons about equally well. We explain known balanced distributions of junk DNA within genomes and between subgenomes in allopolyploids (and our hypothesis passes "the onion test" for any so-called solution to the C-value paradox). Importantly, when the allotetraploid maize chromosomes delete redundant genes, their nearby transposons are also lost; this result is explained if transposons near genes function. The Genome Balance Hypothesis is hypothetical because the position effect mechanisms implicated are not proved to apply to all junk DNA, and the continuous nature of the centromeric and gene position effects have not yet been studied as a single phenomenon.
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Affiliation(s)
- Michael Freeling
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA.
| | - Jie Xu
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA; Maize Research Institute, Sichuan Agricultural University, Wenjiang, Sichuan 611130, China
| | - Margaret Woodhouse
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720, USA
| | - Damon Lisch
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA
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50
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Zuccolo A, Scofield DG, De Paoli E, Morgante M. The Ty1-copia LTR retroelement family PARTC is highly conserved in conifers over 200 MY of evolution. Gene 2015; 568:89-99. [PMID: 25982862 DOI: 10.1016/j.gene.2015.05.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2015] [Revised: 04/06/2015] [Accepted: 05/11/2015] [Indexed: 11/26/2022]
Abstract
Long Terminal Repeat retroelements (LTR-RTs) are a major component of many plant genomes. Although well studied and described in angiosperms, their features and dynamics are poorly understood in gymnosperms. Representative complete copies of a Ty1-copia element isolate in Picea abies and named PARTC were identified in six other conifer species (Picea glauca, Pinus sylvestris, Pinus taeda, Abies sibirica, Taxus baccata and Juniperus communis) covering more than 200 million years of evolution. Here we characterized the structure of this element, assessed its abundance across conifers, studied the modes and timing of its amplification, and evaluated the degree of conservation of its extant copies at nucleotide level over distant species. We demonstrated that the element is ancient, abundant, widespread and its paralogous copies are present in the genera Picea, Pinus and Abies as an LTR-RT family. The amplification leading to the extant copies of PARTC occurred over long evolutionary times spanning 10s of MY and mostly took place after the speciation of the conifers analyzed. The level of conservation of PARTC is striking and may be explained by low substitution rates and limited removal mechanisms for LTR-RTs. These PARTC features and dynamics are representative of a more general scenario for LTR-RTs in gymnosperms quite different from that characterizing the vast majority of LTR-RT elements in angiosperms.
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Affiliation(s)
- Andrea Zuccolo
- Institute of Life Sciences, Scuola Superiore Sant'Anna, 56127 Pisa, Italy; Istituto di Genomica Applicata, Via J. Linussio 51, 33100 Udine, Italy.
| | - Douglas G Scofield
- Department of Evolutionary Biology, Evolutionary Biology Centre, Uppsala University, SE-75236 Uppsala, Sweden
| | - Emanuele De Paoli
- Università degli Studi di Udine, Via delle Scienze 208, 33100 Udine, Italy
| | - Michele Morgante
- Istituto di Genomica Applicata, Via J. Linussio 51, 33100 Udine, Italy; Università degli Studi di Udine, Via delle Scienze 208, 33100 Udine, Italy
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