1
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Fallet M, Wilson R, Sarkies P. Cisplatin exposure alters tRNA-derived small RNAs but does not affect epimutations in C. elegans. BMC Biol 2023; 21:276. [PMID: 38031056 PMCID: PMC10688063 DOI: 10.1186/s12915-023-01767-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2023] [Accepted: 11/13/2023] [Indexed: 12/01/2023] Open
Abstract
BACKGROUND The individual lifestyle and environment of an organism can influence its phenotype and potentially the phenotype of its offspring. The different genetic and non-genetic components of the inheritance system and their mutual interactions are key mechanisms to generate inherited phenotypic changes. Epigenetic changes can be transmitted between generations independently from changes in DNA sequence. In Caenorhabditis elegans, epigenetic differences, i.e. epimutations, mediated by small non-coding RNAs, particularly 22G-RNAs, as well as chromatin have been identified, and their average persistence is three to five generations. In addition, previous research showed that some epimutations had a longer duration and concerned genes that were enriched for multiple components of xenobiotic response pathways. These results raise the possibility that environmental stresses might change the rate at which epimutations occur, with potential significance for adaptation. RESULTS In this work, we explore this question by propagating C. elegans lines either in control conditions or in moderate or high doses of cisplatin, which introduces genotoxic stress by damaging DNA. Our results show that cisplatin has a limited effect on global small non-coding RNA epimutations and epimutations in gene expression levels. However, cisplatin exposure leads to increased fluctuations in the levels of small non-coding RNAs derived from tRNA cleavage. We show that changes in tRNA-derived small RNAs may be associated with gene expression changes. CONCLUSIONS Our work shows that epimutations are not substantially altered by cisplatin exposure but identifies transient changes in tRNA-derived small RNAs as a potential source of variation induced by genotoxic stress.
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Affiliation(s)
- Manon Fallet
- Department of Biochemistry, Evolutionary Epigenetics Group, Dorothy Crowfoot Hodgkin Building, University of Oxford, South Parks Rd., Oxford, OX1 3QU, UK.
- Man-Technology-Environment Research Centre (MTM), School of Science and Technology, Örebro University, Fakultetsgatan 1, 70182, Örebro, Sweden.
| | - Rachel Wilson
- Department of Biochemistry, Evolutionary Epigenetics Group, Dorothy Crowfoot Hodgkin Building, University of Oxford, South Parks Rd., Oxford, OX1 3QU, UK
- MRC London Institute of Medical Sciences, Du Cane Road, London, W12 0NN, UK
- Institute of Clinical Sciences, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Peter Sarkies
- Department of Biochemistry, Evolutionary Epigenetics Group, Dorothy Crowfoot Hodgkin Building, University of Oxford, South Parks Rd., Oxford, OX1 3QU, UK.
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2
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Goeldel C, Johannes F. Stochasticity in gene body methylation. CURRENT OPINION IN PLANT BIOLOGY 2023; 75:102436. [PMID: 37597469 DOI: 10.1016/j.pbi.2023.102436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Revised: 06/30/2023] [Accepted: 07/10/2023] [Indexed: 08/21/2023]
Abstract
Gene body methylation (gbM) is a widely conserved epigenetic feature of plant genomes. Efforts to delineate the mechanisms by which gbM contributes to transcriptional regulation remain largely inconclusive, and its evolutionary significance continues to be debated. Curiously, although steady-state gbM levels are remarkably stable across mitotic and meiotic cell divisions, the methylation status of individual CG dinucleotides in gbM genes is highly stochastic. How can these two seemingly contradictory observations be reconciled? Here, we discuss how stochastic processes relate to gbM maintenance dynamics. We show that a quantitative understanding of these processes can shed deeper insights into the molecular and evolutionary biology of this enigmatic epigenetic trait.
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Affiliation(s)
| | - Frank Johannes
- Plant Epigenomics, Technical University of Munich, Germany.
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3
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Yao N, Zhang Z, Yu L, Hazarika R, Yu C, Jang H, Smith LM, Ton J, Liu L, Stachowicz JJ, Reusch TBH, Schmitz RJ, Johannes F. An evolutionary epigenetic clock in plants. Science 2023; 381:1440-1445. [PMID: 37769069 DOI: 10.1126/science.adh9443] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Accepted: 08/08/2023] [Indexed: 09/30/2023]
Abstract
Molecular clocks are the basis for dating the divergence between lineages over macroevolutionary timescales (~105 to 108 years). However, classical DNA-based clocks tick too slowly to inform us about the recent past. Here, we demonstrate that stochastic DNA methylation changes at a subset of cytosines in plant genomes display a clocklike behavior. This "epimutation clock" is orders of magnitude faster than DNA-based clocks and enables phylogenetic explorations on a scale of years to centuries. We show experimentally that epimutation clocks recapitulate known topologies and branching times of intraspecies phylogenetic trees in the self-fertilizing plant Arabidopsis thaliana and the clonal seagrass Zostera marina, which represent two major modes of plant reproduction. This discovery will open new possibilities for high-resolution temporal studies of plant biodiversity.
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Affiliation(s)
- N Yao
- Department of Genetics, University of Georgia, Athens, GA, USA
| | - Z Zhang
- Plant Epigenomics, Technical University of Munich, Freising, Germany
| | - L Yu
- Marine Evolutionary Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - R Hazarika
- Plant Epigenomics, Technical University of Munich, Freising, Germany
| | - C Yu
- Plant Epigenomics, Technical University of Munich, Freising, Germany
| | - H Jang
- Department of Genetics, University of Georgia, Athens, GA, USA
| | - L M Smith
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - J Ton
- School of Biosciences, University of Sheffield, Sheffield, UK
| | - L Liu
- Department of Statistics, University of Georgia, Athens, GA, USA
| | - J J Stachowicz
- Department of Evolution and Ecology, University of California, Davis, CA, USA
| | - T B H Reusch
- Marine Evolutionary Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - R J Schmitz
- Department of Genetics, University of Georgia, Athens, GA, USA
| | - F Johannes
- Plant Epigenomics, Technical University of Munich, Freising, Germany
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4
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Snyman M, Xu S. The effects of mutations on gene expression and alternative splicing. Proc Biol Sci 2023; 290:20230565. [PMID: 37403507 PMCID: PMC10320348 DOI: 10.1098/rspb.2023.0565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 06/12/2023] [Indexed: 07/06/2023] Open
Abstract
Understanding the relationship between mutations and their genomic and phenotypic consequences has been a longstanding goal of evolutionary biology. However, few studies have investigated the impact of mutations on gene expression and alternative splicing on the genome-wide scale. In this study, we aim to bridge this knowledge gap by utilizing whole-genome sequencing data and RNA sequencing data from 16 obligately parthenogenetic Daphnia mutant lines to investigate the effects of ethyl methanesulfonate-induced mutations on gene expression and alternative splicing. Using rigorous analyses of mutations, expression changes and alternative splicing, we show that trans-effects are the major contributor to the variance in gene expression and alternative splicing between the wild-type and mutant lines, whereas cis mutations only affected a limited number of genes and do not always alter gene expression. Moreover, we show that there is a significant association between differentially expressed genes and exonic mutations, indicating that exonic mutations are an important driver of altered gene expression.
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Affiliation(s)
- Marelize Snyman
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
| | - Sen Xu
- Department of Biology, University of Texas at Arlington, Arlington, TX 76019, USA
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5
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Pisupati R, Nizhynska V, Mollá Morales A, Nordborg M. On the causes of gene-body methylation variation in Arabidopsis thaliana. PLoS Genet 2023; 19:e1010728. [PMID: 37141384 DOI: 10.1371/journal.pgen.1010728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 05/16/2023] [Accepted: 03/31/2023] [Indexed: 05/06/2023] Open
Abstract
Gene-body methylation (gbM) refers to sparse CG methylation of coding regions, which is especially prominent in evolutionarily conserved house-keeping genes. It is found in both plants and animals, but is directly and stably (epigenetically) inherited over multiple generations in the former. Studies in Arabidopsis thaliana have demonstrated that plants originating from different parts of the world exhibit genome-wide differences in gbM, which could reflect direct selection on gbM, but which could also reflect an epigenetic memory of ancestral genetic and/or environmental factors. Here we look for evidence of such factors in F2 plants resulting from a cross between a southern Swedish line with low gbM and a northern Swedish line with high gbM, grown at two different temperatures. Using bisulfite-sequencing data with nucleotide-level resolution on hundreds of individuals, we confirm that CG sites are either methylated (nearly 100% methylation across sampled cells) or unmethylated (approximately 0% methylation across sampled cells), and show that the higher level of gbM in the northern line is due to more sites being methylated. Furthermore, methylation variants almost always show Mendelian segregation, consistent with their being directly and stably inherited through meiosis. To explore how the differences between the parental lines could have arisen, we focused on somatic deviations from the inherited state, distinguishing between gains (relative to the inherited 0% methylation) and losses (relative to the inherited 100% methylation) at each site in the F2 generation. We demonstrate that deviations predominantly affect sites that differ between the parental lines, consistent with these sites being more mutable. Gains and losses behave very differently in terms of the genomic distribution, and are influenced by the local chromatin state. We find clear evidence for different trans-acting genetic polymorphism affecting gains and losses, with those affecting gains showing strong environmental interactions (G×E). Direct effects of the environment were minimal. In conclusion, we show that genetic and environmental factors can change gbM at a cellular level, and hypothesize that these factors can also lead to transgenerational differences between individuals via the inclusion of such changes in the zygote. If true, this could explain genographic pattern of gbM with selection, and would cast doubt on estimates of epimutation rates from inbred lines in constant environments.
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Affiliation(s)
- Rahul Pisupati
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
- Vienna Graduate School of Population Genetics, Institut für Populationsgenetik, Vetmeduni, Vienna, Austria
| | - Viktoria Nizhynska
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Almudena Mollá Morales
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Magnus Nordborg
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
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6
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Yao N, Zhang Z, Yu L, Hazarika R, Yu C, Jang H, Smith LM, Ton J, Liu L, Stachowicz J, Reusch T, Schmitz RJ, Johannes F. An evolutionary epigenetic clock in plants. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.15.532766. [PMID: 36993545 PMCID: PMC10055040 DOI: 10.1101/2023.03.15.532766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Molecular clocks are the basis for dating the divergence between lineages over macro-evolutionary timescales (~10 5 -10 8 years). However, classical DNA-based clocks tick too slowly to inform us about the recent past. Here, we demonstrate that stochastic DNA methylation changes at a subset of cytosines in plant genomes possess a clock-like behavior. This 'epimutation-clock' is orders of magnitude faster than DNA-based clocks and enables phylogenetic explorations on a scale of years to centuries. We show experimentally that epimutation-clocks recapitulate known topologies and branching times of intra-species phylogenetic trees in the selfing plant A. thaliana and the clonal seagrass Z. marina , which represent two major modes of plant reproduction. This discovery will open new possibilities for high-resolution temporal studies of plant biodiversity.
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Affiliation(s)
- N Yao
- Department of Genetics, University of Georgia, Athens, USA
| | - Z Zhang
- Plant Epigenomics, Technical University of Munich, Freising, Germany
| | - L Yu
- Marine Evolutionary Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - R Hazarika
- Plant Epigenomics, Technical University of Munich, Freising, Germany
| | - C Yu
- Plant Epigenomics, Technical University of Munich, Freising, Germany
| | - H Jang
- Department of Genetics, University of Georgia, Athens, USA
| | - L M Smith
- School of Biosciences, University of Sheffield, UK
| | - J Ton
- School of Biosciences, University of Sheffield, UK
| | - L Liu
- Department of Statistics, University of Georgia, Athens, USA
| | - J Stachowicz
- Department of Evolution and Ecology, University of California, Davis, USA
| | - Tbh Reusch
- Marine Evolutionary Ecology, GEOMAR Helmholtz Centre for Ocean Research Kiel, Kiel, Germany
| | - R J Schmitz
- Department of Genetics, University of Georgia, Athens, USA
| | - F Johannes
- Plant Epigenomics, Technical University of Munich, Freising, Germany
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7
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Hafner A, Mackenzie S. Re-analysis of publicly available methylomes using signal detection yields new information. Sci Rep 2023; 13:3307. [PMID: 36849495 PMCID: PMC9971211 DOI: 10.1038/s41598-023-30422-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 02/22/2023] [Indexed: 03/01/2023] Open
Abstract
Cytosine methylation is an epigenetic mark that participates in regulation of gene expression and chromatin stability in plants. Advancements in whole genome sequencing technologies have enabled investigation of methylome dynamics under different conditions. However, the computational methods for analyzing bisulfite sequence data have not been unified. Contention remains in the correlation of differentially methylated positions with the investigated treatment and exclusion of noise, inherent to these stochastic datasets. The prevalent approaches apply Fisher's exact test, logistic, or beta regression, followed by an arbitrary cut-off for differences in methylation levels. A different strategy, the MethylIT pipeline, utilizes signal detection to determine cut-off based on a fitted generalized gamma probability distribution of methylation divergence. Re-analysis of publicly available BS-seq data from two epigenetic studies in Arabidopsis and applying MethylIT revealed additional, previously unreported results. Methylome repatterning in response to phosphate starvation was confirmed to be tissue-specific and included phosphate assimilation genes in addition to sulfate metabolism genes not implicated in the original study. During seed germination plants undergo major methylome reprogramming and use of MethylIT allowed us to identify stage-specific gene networks. We surmise from these comparative studies that robust methylome experiments must account for data stochasticity to achieve meaningful functional analyses.
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Affiliation(s)
- Alenka Hafner
- grid.29857.310000 0001 2097 4281Department of Biology, The Pennsylvania State University, 362 Frear N Bldg, University Park, PA 16802 USA ,grid.29857.310000 0001 2097 4281Intercollege Graduate Degree Program in Plant Biology, The Pennsylvania State University, University Park, PA USA
| | - Sally Mackenzie
- Department of Biology, The Pennsylvania State University, 362 Frear N Bldg, University Park, PA, 16802, USA. .,Department of Plant Science, The Pennsylvania State University, University Park, PA, USA.
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8
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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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9
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Sadhukhan A, Prasad SS, Mitra J, Siddiqui N, Sahoo L, Kobayashi Y, Koyama H. How do plants remember drought? PLANTA 2022; 256:7. [PMID: 35687165 DOI: 10.1007/s00425-022-03924-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2022] [Accepted: 05/21/2022] [Indexed: 06/15/2023]
Abstract
Plants develop both short-term and transgenerational memory of drought stress through epigenetic regulation of transcription for a better response to subsequent exposure. Recurrent spells of droughts are more common than a single drought, with intermittent moist recovery intervals. While the detrimental effects of the first drought on plant structure and physiology are unavoidable, if survived, plants can memorize the first drought to present a more robust response to the following droughts. This includes a partial stomatal opening in the watered recovery interval, higher levels of osmoprotectants and ABA, and attenuation of photosynthesis in the subsequent exposure. Short-term drought memory is regulated by ABA and other phytohormone signaling with transcriptional memory behavior in various genes. High levels of methylated histones are deposited at the drought-tolerance genes. During the recovery interval, the RNA polymerase is stalled to be activated by a pause-breaking factor in the subsequent drought. Drought leads to DNA demethylation near drought-response genes, with genetic control of the process. Progenies of the drought-exposed plants can better adapt to drought owing to the inheritance of particular methylation patterns. However, a prolonged watered recovery interval leads to loss of drought memory, mediated by certain demethylases and chromatin accessibility factors. Small RNAs act as critical regulators of drought memory by altering transcript levels of drought-responsive target genes. Further studies in the future will throw more light on the genetic control of drought memory and the interplay of genetic and epigenetic factors in its inheritance. Plants from extreme environments can give queues to understanding robust memory responses at the ecosystem level.
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Affiliation(s)
- Ayan Sadhukhan
- Department of Bioscience and Bioengineering, Indian Institute of Technology Jodhpur, Karwar, Jodhpur, 342037, India.
| | - Shiva Sai Prasad
- Department of Agriculture, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Guntur, Andhra Pradesh, 522502, India
| | - Jayeeta Mitra
- Department of Botany, Arunachal University of Studies, Arunachal Pradesh, Namsai, 792103, India
| | - Nadeem Siddiqui
- Department of Biotechnology, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Guntur, Andhra Pradesh, 522502, India
| | - Lingaraj Sahoo
- Department of Bioscience and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, 781039, India
| | - Yuriko Kobayashi
- Faculty of Applied Biological Sciences, Gifu University, Gifu, 501-1193, Japan
| | - Hiroyuki Koyama
- Faculty of Applied Biological Sciences, Gifu University, Gifu, 501-1193, Japan
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10
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Vogt G. Paradigm shifts in animal epigenetics: Research on non-model species leads to new insights into dependencies, functions and inheritance of DNA methylation. Bioessays 2022; 44:e2200040. [PMID: 35618444 DOI: 10.1002/bies.202200040] [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: 02/16/2022] [Revised: 05/17/2022] [Accepted: 05/18/2022] [Indexed: 11/06/2022]
Abstract
Recent investigations with non-model species and whole-genome approaches have challenged several paradigms in animal epigenetics. They revealed that epigenetic variation in populations is not the mere consequence of genetic variation, but is a semi-independent or independent source of phenotypic variation, depending on mode of reproduction. DNA methylation is not positively correlated with genome size and phylogenetic position as earlier believed, but has evolved differently between and within higher taxa. Epigenetic marks are usually not completely erased in the zygote and germ cells as generalized from mouse, but often persist and can be transgenerationally inherited, making them evolutionarily relevant. Gene body methylation and promoter methylation are similar in vertebrates and invertebrates with well methylated genomes but transposon silencing through methylation is variable. The new data also suggest that animals use epigenetic mechanisms to cope with rapid environmental changes and to adapt to new environments. The main benefiters are asexual populations, invaders, sessile taxa and long-lived species.
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Affiliation(s)
- Günter Vogt
- Faculty of Biosciences, University of Heidelberg, Heidelberg, Germany
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11
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Leung C, Grulois D, Chevin LM. Plasticity across levels: relating epigenomic, transcriptomic, and phenotypic responses to osmotic stress in a halotolerant microalga. Mol Ecol 2022; 31:4672-4687. [PMID: 35593517 PMCID: PMC9543585 DOI: 10.1111/mec.16542] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 05/12/2022] [Indexed: 12/01/2022]
Abstract
Phenotypic plasticity, the ability of a given genotype to produce alternative phenotypes in response to its environment of development, is an important mechanism for coping with variable environments. While the mechanisms underlying phenotypic plasticity are diverse, their relative contributions need to be investigated quantitatively to better understand the evolvability of plasticity across biological levels. This requires relating plastic responses of the epigenome, transcriptome, and organismal phenotype, and investigating how they vary with the genotype. Here we carried out this approach for responses to osmotic stress in Dunaliella salina, a green microalga that is a model organism for salinity tolerance. We compared two strains that show markedly different demographic responses to osmotic stress, and showed that these phenotypic responses involve strain‐ and environment‐specific variation in gene expression levels, but a relative low—albeit significant—effect of strain × environment interaction. We also found an important genotype effect on the genome‐wide methylation pattern, but little contribution from environmental conditions to the latter. However, we did detect a significant marginal effect of epigenetic variation on gene expression, beyond the influence of genetic differences on epigenetic state, and we showed that hypomethylated regions are correlated with higher gene expression. Our results indicate that epigenetic mechanisms are either not involved in the rapid plastic response to environmental change in this species, or involve only few changes in trans that are sufficient to trigger concerted changes in the expression of many genes, and phenotypic responses by multiple traits.
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Affiliation(s)
- Christelle Leung
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, Montpellier, France
| | - Daphné Grulois
- CEFE, Université de Montpellier, CNRS, EPHE, IRD, Montpellier, France
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12
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Hazarika RR, Serra M, Zhang Z, Zhang Y, Schmitz RJ, Johannes F. Molecular properties of epimutation hotspots. NATURE PLANTS 2022; 8:146-156. [PMID: 35087209 PMCID: PMC8866225 DOI: 10.1038/s41477-021-01086-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 12/08/2021] [Indexed: 06/14/2023]
Abstract
Mistakes in the maintenance of CG methylation are a source of heritable epimutations in plants. Multigenerational surveys indicate that the rate of these stochastic events varies substantially across the genome, with some regions harbouring localized 'epimutation hotspots'. Using Arabidopsis as a model, we show that epimutation hotspots are indexed by a specific set of chromatin states that map to subregions of gene body methylation genes. Although these regions comprise only ~12% of all CGs in the genome, they account for ~63% of all epimutation events per unit time. Molecular profiling revealed that these regions contain unique sequence features, harbour steady-state intermediate methylation levels and act as putative targets of antagonistic DNA methylation pathways. We further demonstrate that experimentally induced shifts in steady-state methylation in these hotspot regions are sufficient to significantly alter local epimutation intensities. Our work lays the foundation for dissecting the molecular mechanisms and evolutionary consequences of epimutation hotspots in plants.
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Affiliation(s)
- Rashmi R Hazarika
- Department of Molecular Life Sciences, Technical University of Munich, Freising, Germany
- TUM Institute for Advanced Study, Garching, Germany
| | - Michele Serra
- Department of Molecular Life Sciences, Technical University of Munich, Freising, Germany
| | - Zhilin Zhang
- Department of Molecular Life Sciences, Technical University of Munich, Freising, Germany
| | - Yinwen Zhang
- Department of Genetics, The University of Georgia, Athens, GA, USA
| | - Robert J Schmitz
- TUM Institute for Advanced Study, Garching, Germany.
- Department of Genetics, The University of Georgia, Athens, GA, USA.
| | - Frank Johannes
- Department of Molecular Life Sciences, Technical University of Munich, Freising, Germany.
- TUM Institute for Advanced Study, Garching, Germany.
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13
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Hou Q, Wan X. Epigenome and Epitranscriptome: Potential Resources for Crop Improvement. Int J Mol Sci 2021; 22:12912. [PMID: 34884725 PMCID: PMC8658206 DOI: 10.3390/ijms222312912] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/24/2021] [Accepted: 11/28/2021] [Indexed: 12/26/2022] Open
Abstract
Crop breeding faces the challenge of increasing food demand, especially under climatic changes. Conventional breeding has relied on genetic diversity by combining alleles to obtain desired traits. In recent years, research on epigenetics and epitranscriptomics has shown that epigenetic and epitranscriptomic diversity provides additional sources for crop breeding and harnessing epigenetic and epitranscriptomic regulation through biotechnologies has great potential for crop improvement. Here, we review epigenome and epitranscriptome variations during plant development and in response to environmental stress as well as the available sources for epiallele formation. We also discuss the possible strategies for applying epialleles and epitranscriptome engineering in crop breeding.
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Affiliation(s)
- Quancan Hou
- Zhongzhi International Institute of Agricultural Biosciences, Shunde Graduate School, Research Center of Biology and Agriculture, University of Science and Technology Beijing (USTB), Beijing 100024, China
- Beijing Engineering Laboratory of Main Crop Bio-Tech Breeding, Beijing International Science and Technology Cooperation Base of Bio-Tech Breeding, Beijing Solidwill Sci-Tech Co., Ltd., Beijing 100192, China
| | - Xiangyuan Wan
- Zhongzhi International Institute of Agricultural Biosciences, Shunde Graduate School, Research Center of Biology and Agriculture, University of Science and Technology Beijing (USTB), Beijing 100024, China
- Beijing Engineering Laboratory of Main Crop Bio-Tech Breeding, Beijing International Science and Technology Cooperation Base of Bio-Tech Breeding, Beijing Solidwill Sci-Tech Co., Ltd., Beijing 100192, China
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Kakoulidou I, Avramidou EV, Baránek M, Brunel-Muguet S, Farrona S, Johannes F, Kaiserli E, Lieberman-Lazarovich M, Martinelli F, Mladenov V, Testillano PS, Vassileva V, Maury S. Epigenetics for Crop Improvement in Times of Global Change. BIOLOGY 2021; 10:766. [PMID: 34439998 PMCID: PMC8389687 DOI: 10.3390/biology10080766] [Citation(s) in RCA: 37] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 08/04/2021] [Accepted: 08/06/2021] [Indexed: 12/15/2022]
Abstract
Epigenetics has emerged as an important research field for crop improvement under the on-going climatic changes. Heritable epigenetic changes can arise independently of DNA sequence alterations and have been associated with altered gene expression and transmitted phenotypic variation. By modulating plant development and physiological responses to environmental conditions, epigenetic diversity-naturally, genetically, chemically, or environmentally induced-can help optimise crop traits in an era challenged by global climate change. Beyond DNA sequence variation, the epigenetic modifications may contribute to breeding by providing useful markers and allowing the use of epigenome diversity to predict plant performance and increase final crop production. Given the difficulties in transferring the knowledge of the epigenetic mechanisms from model plants to crops, various strategies have emerged. Among those strategies are modelling frameworks dedicated to predicting epigenetically controlled-adaptive traits, the use of epigenetics for in vitro regeneration to accelerate crop breeding, and changes of specific epigenetic marks that modulate gene expression of traits of interest. The key challenge that agriculture faces in the 21st century is to increase crop production by speeding up the breeding of resilient crop species. Therefore, epigenetics provides fundamental molecular information with potential direct applications in crop enhancement, tolerance, and adaptation within the context of climate change.
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Affiliation(s)
- Ioanna Kakoulidou
- Department of Molecular Life Sciences, Technical University of Munich, Liesel-Beckmann-Str. 2, 85354 Freising, Germany; (I.K.); (F.J.)
| | - Evangelia V. Avramidou
- Laboratory of Forest Genetics and Biotechnology, Institute of Mediterranean Forest Ecosystems, Hellenic Agricultural Organization-Dimitra (ELGO-DIMITRA), 11528 Athens, Greece;
| | - Miroslav Baránek
- Faculty of Horticulture, Mendeleum—Institute of Genetics, Mendel University in Brno, Valtická 334, 69144 Lednice, Czech Republic;
| | - Sophie Brunel-Muguet
- UMR 950 Ecophysiologie Végétale, Agronomie et Nutritions N, C, S, UNICAEN, INRAE, Normandie Université, CEDEX, F-14032 Caen, France;
| | - Sara Farrona
- Plant and AgriBiosciences Centre, Ryan Institute, National University of Ireland (NUI) Galway, H91 TK33 Galway, Ireland;
| | - Frank Johannes
- Department of Molecular Life Sciences, Technical University of Munich, Liesel-Beckmann-Str. 2, 85354 Freising, Germany; (I.K.); (F.J.)
- Institute for Advanced Study, Technical University of Munich, Lichtenberg Str. 2a, 85748 Garching, Germany
| | - Eirini Kaiserli
- Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, Bower Building, University of Glasgow, Glasgow G12 8QQ, UK;
| | - Michal Lieberman-Lazarovich
- Institute of Plant Sciences, Agricultural Research Organization, Volcani Center, Rishon LeZion 7505101, Israel;
| | - Federico Martinelli
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy;
| | - Velimir Mladenov
- Faculty of Agriculture, University of Novi Sad, Sq. Dositeja Obradovića 8, 21000 Novi Sad, Serbia;
| | - Pilar S. Testillano
- Pollen Biotechnology of Crop Plants Group, Centro de Investigaciones Biológicas Margarita Salas-(CIB-CSIC), Ramiro Maeztu 9, 28040 Madrid, Spain;
| | - Valya Vassileva
- Department of Molecular Biology and Genetics, Institute of Plant Physiology and Genetics, Bulgarian Academy of Sciences, Acad. Georgi Bonchev Str., Bldg. 21, 1113 Sofia, Bulgaria;
| | - Stéphane Maury
- Laboratoire de Biologie des Ligneux et des Grandes Cultures, INRAE, EA1207 USC1328, Université d’Orléans, F-45067 Orléans, France
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Yao N, Schmitz RJ, Johannes F. Epimutations Define a Fast-Ticking Molecular Clock in Plants. Trends Genet 2021; 37:699-710. [PMID: 34016450 PMCID: PMC8282728 DOI: 10.1016/j.tig.2021.04.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/15/2021] [Accepted: 04/16/2021] [Indexed: 12/16/2022]
Abstract
Stochastic gains and losses of DNA methylation at CG dinucleotides are a frequent occurrence in plants. These spontaneous 'epimutations' occur at a rate that is 100 000 times higher than the genetic mutation rate, are effectively neutral at the genome-wide scale, and are stably inherited across mitotic and meiotic cell divisions. Mathematical models have been extraordinarily successful at describing how epimutations accumulate in plant genomes over time, making this process one of the most predictable epigenetic phenomena to date. Here, we propose that their high rate and effective neutrality make epimutations a powerful new molecular clock for timing evolutionary events of the recent past and for age dating of long-lived perennials such as trees.
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Affiliation(s)
- Nan Yao
- Department of Genetics, University of Georgia, Athens, GA, USA
| | - Robert J Schmitz
- Department of Genetics, University of Georgia, Athens, GA, USA; Institute for Advanced Study, Technical University of Munich, Garching, Germany
| | - Frank Johannes
- Institute for Advanced Study, Technical University of Munich, Garching, Germany; Population Epigenetics and Epigenomics, Technical University of Munich, Freising, Germany.
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