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Baduel P, Sammarco I, Barrett R, Coronado‐Zamora M, Crespel A, Díez‐Rodríguez B, Fox J, Galanti D, González J, Jueterbock A, Wootton E, Harney E. The evolutionary consequences of interactions between the epigenome, the genome and the environment. Evol Appl 2024; 17:e13730. [PMID: 39050763 PMCID: PMC11266121 DOI: 10.1111/eva.13730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Revised: 03/30/2024] [Accepted: 05/22/2024] [Indexed: 07/27/2024] Open
Abstract
The epigenome is the suite of interacting chemical marks and molecules that helps to shape patterns of development, phenotypic plasticity and gene regulation, in part due to its responsiveness to environmental stimuli. There is increasing interest in understanding the functional and evolutionary importance of this sensitivity under ecologically realistic conditions. Observations that epigenetic variation abounds in natural populations have prompted speculation that it may facilitate evolutionary responses to rapid environmental perturbations, such as those occurring under climate change. A frequent point of contention is whether epigenetic variants reflect genetic variation or are independent of it. The genome and epigenome often appear tightly linked and interdependent. While many epigenetic changes are genetically determined, the converse is also true, with DNA sequence changes influenced by the presence of epigenetic marks. Understanding how the epigenome, genome and environment interact with one another is therefore an essential step in explaining the broader evolutionary consequences of epigenomic variation. Drawing on results from experimental and comparative studies carried out in diverse plant and animal species, we synthesize our current understanding of how these factors interact to shape phenotypic variation in natural populations, with a focus on identifying similarities and differences between taxonomic groups. We describe the main components of the epigenome and how they vary within and between taxa. We review how variation in the epigenome interacts with genetic features and environmental determinants, with a focus on the role of transposable elements (TEs) in integrating the epigenome, genome and environment. And we look at recent studies investigating the functional and evolutionary consequences of these interactions. Although epigenetic differentiation in nature is likely often a result of drift or selection on stochastic epimutations, there is growing evidence that a significant fraction of it can be stably inherited and could therefore contribute to evolution independently of genetic change.
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Affiliation(s)
- Pierre Baduel
- Institut de Biologie de l'Ecole Normale SupérieurePSL University, CNRSParisFrance
| | - Iris Sammarco
- Institute of Botany of the Czech Academy of SciencesPrůhoniceCzechia
| | - Rowan Barrett
- Redpath Museum and Department of BiologyMcGill UniversityMontrealCanada
| | | | | | | | - Janay Fox
- Redpath Museum and Department of BiologyMcGill UniversityMontrealCanada
| | - Dario Galanti
- Institute of Evolution and Ecology (EvE)University of TuebingenTübingenGermany
| | | | - Alexander Jueterbock
- Algal and Microbial Biotechnology Division, Faculty of Biosciences and AquacultureNord UniversityBodøNorway
| | - Eric Wootton
- Redpath Museum and Department of BiologyMcGill UniversityMontrealCanada
| | - Ewan Harney
- Institute of Evolutionary BiologyCSIC, UPFBarcelonaSpain
- School of BiosciencesUniversity of SheffieldSheffieldUK
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2
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Horvath R, Minadakis N, Bourgeois Y, Roulin AC. The evolution of transposable elements in Brachypodium distachyon is governed by purifying selection, while neutral and adaptive processes play a minor role. eLife 2024; 12:RP93284. [PMID: 38606833 PMCID: PMC11014726 DOI: 10.7554/elife.93284] [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] [Indexed: 04/13/2024] Open
Abstract
Understanding how plants adapt to changing environments and the potential contribution of transposable elements (TEs) to this process is a key question in evolutionary genomics. While TEs have recently been put forward as active players in the context of adaptation, few studies have thoroughly investigated their precise role in plant evolution. Here, we used the wild Mediterranean grass Brachypodium distachyon as a model species to identify and quantify the forces acting on TEs during the adaptation of this species to various conditions, across its entire geographic range. Using sequencing data from more than 320 natural B. distachyon accessions and a suite of population genomics approaches, we reveal that putatively adaptive TE polymorphisms are rare in wild B. distachyon populations. After accounting for changes in past TE activity, we show that only a small proportion of TE polymorphisms evolved neutrally (<10%), while the vast majority of them are under moderate purifying selection regardless of their distance to genes. TE polymorphisms should not be ignored when conducting evolutionary studies, as they can be linked to adaptation. However, our study clearly shows that while they have a large potential to cause phenotypic variation in B. distachyon, they are not favored during evolution and adaptation over other types of mutations (such as point mutations) in this species.
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Affiliation(s)
- Robert Horvath
- Department of Plant and Microbial Biology, University of ZurichZurichSwitzerland
| | - Nikolaos Minadakis
- Department of Plant and Microbial Biology, University of ZurichZurichSwitzerland
| | - Yann Bourgeois
- DIADE, University of Montpellier, CIRAD, IRDMontpellierFrance
- University of PortsmouthPortsmouthUnited Kingdom
| | - Anne C Roulin
- Department of Plant and Microbial Biology, University of ZurichZurichSwitzerland
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3
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D'Amico-Willman KM, Niederhuth CE, Sovic MG, Anderson ES, Gradziel TM, Fresnedo-Ramírez J. Hypermethylation and small RNA expression are associated with increased age in almond (Prunus dulcis [Mill.] D.A. Webb) accessions. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 338:111918. [PMID: 37956826 DOI: 10.1016/j.plantsci.2023.111918] [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: 07/24/2023] [Revised: 10/20/2023] [Accepted: 11/04/2023] [Indexed: 11/15/2023]
Abstract
The focus of this study is to profile changes in DNA methylation and small RNA expression occurring with increased age in almond breeding germplasm to identify possible biomarkers of age that can be used to assess the potential of individuals to develop aging-related disorders. To profile DNA methylation in almond germplasm, 70 methylomes were generated from almond individuals representing three age cohorts (11, 7, and 2 years old) using an enzymatic methyl-seq approach followed by analysis to call differentially methylated regions (DMRs) within these cohorts. Small RNA (sRNA) expression was profiled in three breeding selections, each from two age cohorts (1 and 6 years old), using sRNA-Seq followed by differential expression analysis. Weighted chromosome-level methylation analysis reveals hypermethylation in 11-year-old almond breeding selections when compared to 2-year-old selections in the CG and CHH contexts. Seventeen consensus DMRs were identified in all age contrasts. sRNA expression differed significantly between the two age cohorts tested, with significantly decreased expression in sRNAs in the 6-year-old selections compared to the 1-year-old. Almond shows a pattern of hypermethylation and decreased sRNA expression with increased age. Identified DMRs and differentially expressed sRNAs could function as putative biomarkers of age following validation in additional age groups.
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Affiliation(s)
| | - Chad E Niederhuth
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824, USA
| | - Michael G Sovic
- Center for Applied Plant Sciences, The Ohio State University, Columbus, OH 43210, USA
| | - Elizabeth S Anderson
- Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691, USA
| | - Thomas M Gradziel
- Department of Plant Sciences, University of California, Davis, CA 95616, USA
| | - Jonathan Fresnedo-Ramírez
- Translational Plant Sciences, The Ohio State University, Columbus, OH 43210, USA; Center for Applied Plant Sciences, The Ohio State University, Columbus, OH 43210, USA; Department of Horticulture and Crop Science, Ohio Agricultural Research and Development Center, The Ohio State University, Wooster, OH 44691, USA.
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4
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Nakashima K, Yuhazu M, Mikuriya S, Kasai M, Abe J, Taneda A, Kanazawa A. Frequency of cytosine methylation in the adjacent regions of soybean retrotransposon SORE-1 depends on chromosomal location. Genome 2024; 67:1-12. [PMID: 37746933 DOI: 10.1139/gen-2023-0044] [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: 09/26/2023]
Abstract
Mobilization of transposable elements (TEs) is suppressed by epigenetic mechanisms involving cytosine methylation. However, few studies have focused on clarifying relationships between epigenetic influences of TEs on the adjacent DNA regions and time after insertion of TEs into the genome and/or their chromosomal location. Here we addressed these issues using soybean retrotransposon SORE-1. We analyzed SORE-1, inserted in exon 1 of the GmphyA2 gene, one of the newest insertions in this family so far identified. Cytosine methylation was detected in this element but was barely present in the adjacent regions. These results were correlated, respectively, with the presence and absence of the production of short interfering RNAs. Cytosine methylation profiles of 74 SORE-1 elements in the Williams 82 reference genome indicated that methylation frequency in the adjacent regions of SORE-1 was profoundly higher in pericentromeric regions than in euchromatic chromosome arms and was only weakly correlated with the length of time after insertion into the genome. Notably, the higher level of methylation in the 5' adjacent regions of SORE-1 coincided with the presence of repetitive elements in pericentromeric regions. Together, these results suggest that epigenetic influence of SORE-1 on the adjacent regions is influenced by its location on the chromosome.
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Affiliation(s)
- Kenta Nakashima
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Mashiro Yuhazu
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Shun Mikuriya
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Megumi Kasai
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Jun Abe
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
| | - Akito Taneda
- Graduate School of Science and Technology, Hirosaki University, Hirosaki, Aomori 036-8561, Japan
| | - Akira Kanazawa
- Research Faculty of Agriculture, Hokkaido University, Sapporo 060-8589, Japan
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5
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Zhang GJ, Jia KL, Wang J, Gao WJ, Li SF. Genome-wide analysis of transposable elements and satellite DNA in Humulus scandens, a dioecious plant with XX/XY 1Y 2 chromosomes. FRONTIERS IN PLANT SCIENCE 2023; 14:1230250. [PMID: 37908838 PMCID: PMC10614002 DOI: 10.3389/fpls.2023.1230250] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 10/04/2023] [Indexed: 11/02/2023]
Abstract
Transposable elements (TEs) and satellite DNAs, two major categories of repetitive sequences, are expected to accumulate in non-recombining genome regions, including sex-linked regions, and contribute to sex chromosome evolution. The dioecious plant, Humulus scandens, can be used for studying the evolution of the XX/XY1Y2 sex chromosomes. In this study, we thoroughly examined the repetitive components of male and female H. scandens using next-generation sequencing data followed by bioinformatics analysis and florescence in situ hybridization (FISH). The H. scandens genome has a high overall repetitive sequence composition, 68.30% in the female and 66.78% in the male genome, with abundant long terminal repeat (LTR) retrotransposons (RTs), including more Ty3/Gypsy than Ty1/Copia elements, particularly two Ty3/Gypsy lineages, Tekay and Retand. Most LTR-RT lineages were found dispersed across the chromosomes, though CRM and Athila elements were predominately found within the centromeres and the pericentromeric regions. The Athila elements also showed clearly higher FISH signal intensities in the Y1 and Y2 chromosomes than in the X or autosomes. Three novel satellite DNAs were specifically distributed in the centromeric and/or telomeric regions, with markedly different distributions on the X, Y1, and Y2 chromosomes. Combined with FISH using satellite DNAs to stain chromosomes during meiotic diakinesis, we determined the synapsis pattern and distinguish pseudoautosomal regions (PARs). The results indicate that the XY1Y2 sex chromosomes of H. scandens might have originated from a centric fission event. This study improves our understanding of the repetitive sequence organization of H. scandens genome and provides a basis for further analysis of their chromosome evolution process.
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Affiliation(s)
- Guo-Jun Zhang
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, China
- College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Ke-Li Jia
- College of Life Sciences, Henan Normal University, Xinxiang, China
- SanQuan Medical College, Xinxiang Medical University, Xinxiang, China
| | - Jin Wang
- College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Wu-Jun Gao
- College of Life Sciences, Henan Normal University, Xinxiang, China
| | - Shu-Fen Li
- College of Life Sciences, Henan Normal University, Xinxiang, China
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6
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Hämälä T, Ning W, Kuittinen H, Aryamanesh N, Savolainen O. Environmental response in gene expression and DNA methylation reveals factors influencing the adaptive potential of Arabidopsis lyrata. eLife 2022; 11:83115. [PMID: 36306157 PMCID: PMC9616567 DOI: 10.7554/elife.83115] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/12/2022] [Indexed: 11/13/2022] Open
Abstract
Understanding what factors influence plastic and genetic variation is valuable for predicting how organisms respond to changes in the selective environment. Here, using gene expression and DNA methylation as molecular phenotypes, we study environmentally induced variation among Arabidopsis lyrata plants grown at lowland and alpine field sites. Our results show that gene expression is highly plastic, as many more genes are differentially expressed between the field sites than between populations. These environmentally responsive genes evolve under strong selective constraint – the strength of purifying selection on the coding sequence is high, while the rate of adaptive evolution is low. We find, however, that positive selection on cis-regulatory variants has likely contributed to the maintenance of genetically variable environmental responses, but such variants segregate only between distantly related populations. In contrast to gene expression, DNA methylation at genic regions is largely insensitive to the environment, and plastic methylation changes are not associated with differential gene expression. Besides genes, we detect environmental effects at transposable elements (TEs): TEs at the high-altitude field site have higher expression and methylation levels, suggestive of a broad-scale TE activation. Compared to the lowland population, plants native to the alpine environment harbor an excess of recent TE insertions, and we observe that specific TE families are enriched within environmentally responsive genes. Our findings provide insight into selective forces shaping plastic and genetic variation. We also highlight how plastic responses at TEs can rapidly create novel heritable variation in stressful conditions.
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Affiliation(s)
- Tuomas Hämälä
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
| | - Weixuan Ning
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
| | - Helmi Kuittinen
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
| | - Nader Aryamanesh
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
| | - Outi Savolainen
- Department of Ecology and Genetics, University of Oulu, Oulu, Finland
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7
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Hasterok R, Catalan P, Hazen SP, Roulin AC, Vogel JP, Wang K, Mur LAJ. Brachypodium: 20 years as a grass biology model system; the way forward? TRENDS IN PLANT SCIENCE 2022; 27:1002-1016. [PMID: 35644781 DOI: 10.1016/j.tplants.2022.04.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 04/13/2022] [Accepted: 04/26/2022] [Indexed: 06/15/2023]
Abstract
It has been 20 years since Brachypodium distachyon was suggested as a model grass species, but ongoing research now encompasses the entire genus. Extensive Brachypodium genome sequencing programmes have provided resources to explore the determinants and drivers of population diversity. This has been accompanied by cytomolecular studies to make Brachypodium a platform to investigate speciation, polyploidisation, perenniality, and various aspects of chromosome and interphase nucleus organisation. The value of Brachypodium as a functional genomic platform has been underscored by the identification of key genes for development, biotic and abiotic stress, and cell wall structure and function. While Brachypodium is relevant to the biofuel industry, its impact goes far beyond that as an intriguing model to study climate change and combinatorial stress.
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Affiliation(s)
- Robert Hasterok
- Plant Cytogenetics and Molecular Biology Group, Institute of Biology, Biotechnology and Environmental Protection, Faculty of Natural Sciences, University of Silesia in Katowice, Katowice 40-032, Poland.
| | - Pilar Catalan
- Department of Agricultural and Environmental Sciences, High Polytechnic School of Huesca, University of Zaragoza, Huesca 22071, Spain; Grupo de Bioquímica, Biofísica y Biología Computacional (BIFI, UNIZAR), Unidad Asociada al CSIC, Zaragoza E-50059, Spain
| | - Samuel P Hazen
- Biology Department, University of Massachusetts Amherst, Amherst, MA 01003, USA
| | - Anne C Roulin
- Department of Plant and Microbial Biology, University of Zürich, Zürich 8008, Switzerland
| | - John P Vogel
- DOE Joint Genome Institute, Berkeley, CA 94720, USA; University California, Berkeley, Berkeley, CA 94720, USA
| | - Kai Wang
- School of Life Sciences, Nantong University, Nantong 226019, Jiangsu, China
| | - Luis A J Mur
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Edward Llwyd Building, Aberystwyth SY23 3DA, UK; College of Agronomy, Shanxi Agricultural University, Taiyuan 030801, Shanxi, China.
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8
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Klein SP, Anderson SN. The evolution and function of transposons in epigenetic regulation in response to the environment. CURRENT OPINION IN PLANT BIOLOGY 2022; 69:102277. [PMID: 35961279 DOI: 10.1016/j.pbi.2022.102277] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 06/21/2022] [Accepted: 07/07/2022] [Indexed: 06/15/2023]
Abstract
Transposable elements (TEs) make up a major proportion of plant genomes. Despite their prevalence genome-wide, TEs are often tossed aside as "junk DNA" since they rarely cause phenotypes, and epigenetic mechanisms silence TEs to prevent them from causing deleterious mutations through movement. While this bleak picture of TEs in genomes is true on average, a growing number of examples across many plant species point to TEs as drivers of phenotypic diversity and novel stress responses. Examples of TE-influenced phenotypes illustrate the many ways that novel transposition events can alter local gene expression and how this relates to potential variation in plant responses to environmental stress. Since TE families and insertions at the locus level lack evolutionary conservation, advancements in the field will require TE experts across diverse species to identify and utilize TE variation in their own systems as a means of crop improvement.
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Affiliation(s)
- Stephanie P Klein
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA
| | - Sarah N Anderson
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA 50011, USA.
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9
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Sharbrough J, Conover JL, Gyorfy MF, Grover CE, Miller ER, Wendel JF, Sloan DB. Global Patterns of subgenome evolution in organelle-targeted genes of six allotetraploid angiosperms. Mol Biol Evol 2022; 39:6564157. [PMID: 35383845 PMCID: PMC9040051 DOI: 10.1093/molbev/msac074] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
Abstract
Whole-genome duplications (WGDs) are a prominent process of diversification in eukaryotes. The genetic and evolutionary forces that WGD imposes on cytoplasmic genomes are not well understood, despite the central role that cytonuclear interactions play in eukaryotic function and fitness. Cellular respiration and photosynthesis depend on successful interaction between the 3,000+ nuclear-encoded proteins destined for the mitochondria or plastids and the gene products of cytoplasmic genomes in multi-subunit complexes such as OXPHOS, organellar ribosomes, Photosystems I and II, and Rubisco. Allopolyploids are thus faced with the critical task of coordinating interactions between the nuclear and cytoplasmic genes that were inherited from different species. Because the cytoplasmic genomes share a more recent history of common descent with the maternal nuclear subgenome than the paternal subgenome, evolutionary “mismatches” between the paternal subgenome and the cytoplasmic genomes in allopolyploids might lead to the accelerated rates of evolution in the paternal homoeologs of allopolyploids, either through relaxed purifying selection or strong directional selection to rectify these mismatches. We report evidence from six independently formed allotetraploids that the subgenomes exhibit unequal rates of protein-sequence evolution, but we found no evidence that cytonuclear incompatibilities result in altered evolutionary trajectories of the paternal homoeologs of organelle-targeted genes. The analyses of gene content revealed mixed evidence for whether the organelle-targeted genes are lost more rapidly than the non-organelle-targeted genes. Together, these global analyses provide insights into the complex evolutionary dynamics of allopolyploids, showing that the allopolyploid subgenomes have separate evolutionary trajectories despite sharing the same nucleus, generation time, and ecological context.
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Affiliation(s)
- Joel Sharbrough
- Biology Department, Colorado State University, Fort Collins, CO, USA.,Biology Department, New Mexico Institute of Mining and Technology, Socorro, NM, USA
| | - Justin L Conover
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | | | - Corrinne E Grover
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Emma R Miller
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Jonathan F Wendel
- Department of Ecology, Evolution, and Organismal Biology, Iowa State University, Ames, IA, USA
| | - Daniel B Sloan
- Biology Department, Colorado State University, Fort Collins, CO, USA
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Li L, Chen X, Fang D, Dong S, Guo X, Li N, Campos‐Dominguez L, Wang W, Liu Y, Lang X, Peng Y, Tian D, Thomas DC, Mu W, Liu M, Wu C, Yang T, Zhang S, Yang L, Yang J, Liu Z, Zhang L, Zhang X, Chen F, Jiao Y, Guo Y, Hughes M, Wang W, Liu X, Zhong C, Li A, Sahu SK, Yang H, Wu E, Sharbrough J, Lisby M, Liu X, Xu X, Soltis DE, Van de Peer Y, Kidner C, Zhang S, Liu H. Genomes shed light on the evolution of Begonia, a mega-diverse genus. THE NEW PHYTOLOGIST 2022; 234:295-310. [PMID: 34997964 PMCID: PMC7612470 DOI: 10.1111/nph.17949] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2021] [Accepted: 12/20/2021] [Indexed: 05/02/2023]
Abstract
Clarifying the evolutionary processes underlying species diversification and adaptation is a key focus of evolutionary biology. Begonia (Begoniaceae) is one of the most species-rich angiosperm genera with c. 2000 species, most of which are shade-adapted. Here, we present chromosome-scale genome assemblies for four species of Begonia (B. loranthoides, B. masoniana, B. darthvaderiana and B. peltatifolia), and whole genome shotgun data for an additional 74 Begonia representatives to investigate lineage evolution and shade adaptation of the genus. The four genome assemblies range in size from 331.75 Mb (B. peltatifolia) to 799.83 Mb (B. masoniana), and harbor 22 059-23 444 protein-coding genes. Synteny analysis revealed a lineage-specific whole-genome duplication (WGD) that occurred just before the diversification of Begonia. Functional enrichment of gene families retained after WGD highlights the significance of modified carbohydrate metabolism and photosynthesis possibly linked to shade adaptation in the genus, which is further supported by expansions of gene families involved in light perception and harvesting. Phylogenomic reconstructions and genomics studies indicate that genomic introgression has also played a role in the evolution of Begonia. Overall, this study provides valuable genomic resources for Begonia and suggests potential drivers underlying the diversity and adaptive evolution of this mega-diverse clade.
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11
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Zhang Z, Liu J, Sun Y, Wang S, Xing X, Feng X, Pérez-Pérez JM, Li Y. Genome-wide high-resolution mapping of DNA methylation reveals epigenetic variation in the offspring of sexual and asexual propagation in Robinia pseudoacacia. PLANT CELL REPORTS 2021; 40:2435-2447. [PMID: 34524479 DOI: 10.1007/s00299-021-02787-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 09/07/2021] [Indexed: 06/13/2023]
Abstract
We detected the genome-wide pattern of DNA methylation and its association with gene expression in sexual and asexual progenies of mature Robinia pseudoacacia trees. DNA methylation plays an important role in plant reproduction and development. Although some studies on sexual reproduction have been carried out in model plants, little is known about the dynamic changes in DNA methylation and their effect on gene expression in sexual and asexual progeny of woody plants. Here, through whole-genome bisulfite sequencing, we revealed DNA methylation patterns in the sexual and asexual progenies of mature Robinia pseudoacacia to understand the regulation of gene expression by DNA methylation in juvenile seedlings. An average of 53% CG, 34% CHG and 5% CHH contexts was methylated in the leaves of mature and juvenile individuals. The CHH methylation level of asexually propagated seedlings was significantly lower than that of seed-derived seedlings and mature trees. The intergenic regions had the highest methylation level. Analysis of differentially methylated regions (DMRs) showed that most of them were hypermethylated and located in the gene upstream and introns. A total of 24, 108 and 162 differentially expressed genes containing DMRs were identified in root sprouts (RSs), root cuttings (RCs) and seed-derived seedlings (SSs), respectively, and a large proportion of them showed hypermethylation. In addition, DMRs were enriched within GO subcategories including catalytic activity, metabolic process and cellular process. The results reveal widespread DNA methylation changes between mature plants and their progenies through sexual/asexual reproduction, which provides novel insights into DNA methylation reprogramming and the regulation of gene expression in woody plants.
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Affiliation(s)
- Zijie Zhang
- National Engineering Laboratory for Tree Breeding, College of Biological Science and Technology, Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, Beijing Forestry University, Beijing, 100083, People's Republic of China
| | - Jie Liu
- National Engineering Laboratory for Tree Breeding, College of Biological Science and Technology, Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, Beijing Forestry University, Beijing, 100083, People's Republic of China
| | - Yuhan Sun
- National Engineering Laboratory for Tree Breeding, College of Biological Science and Technology, Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, Beijing Forestry University, Beijing, 100083, People's Republic of China
| | - Shaoming Wang
- State-Owned Quanbaoshan Forestry Station in Luoning County of He'nan Province, Luoyang, 471717, People's Republic of China
| | - Xiuxia Xing
- Agricultural Service Center of Wangfan Hui Town in Luoning County of He'nan Province, Luoyang, 471700, People's Republic of China
| | - Xiaojing Feng
- State-Owned Lvcun Forestry Station in Luoning County of He'nan Province, Luoyang, 471700, People's Republic of China
| | | | - Yun Li
- National Engineering Laboratory for Tree Breeding, College of Biological Science and Technology, Beijing Advanced Innovation Center for Tree Breeding by Molecular Design, Engineering Technology Research Center of Black Locust of National Forestry and Grassland Administration, Beijing Forestry University, Beijing, 100083, People's Republic of China.
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12
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The Underlying Nature of Epigenetic Variation: Origin, Establishment, and Regulatory Function of Plant Epialleles. Int J Mol Sci 2021; 22:ijms22168618. [PMID: 34445323 PMCID: PMC8395315 DOI: 10.3390/ijms22168618] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 08/03/2021] [Accepted: 08/08/2021] [Indexed: 11/17/2022] Open
Abstract
In plants, the gene expression and associated phenotypes can be modulated by dynamic changes in DNA methylation, occasionally being fixed in certain genomic loci and inherited stably as epialleles. Epiallelic variations in a population can occur as methylation changes at an individual cytosine position, methylation changes within a stretch of genomic regions, and chromatin changes in certain loci. Here, we focus on methylated regions, since it is unclear whether variations at individual methylated cytosines can serve any regulatory function, and the evidence for heritable chromatin changes independent of genetic changes is limited. While DNA methylation is known to affect and regulate wide arrays of plant phenotypes, most epialleles in the form of methylated regions have not been assigned any biological function. Here, we review how epialleles can be established in plants, serve a regulatory function, and are involved in adaptive processes. Recent studies suggest that most epialleles occur as byproducts of genetic variations, mainly from structural variants and Transposable Element (TE) activation. Nevertheless, epialleles that occur spontaneously independent of any genetic variations have also been described across different plant species. Here, we discuss how epialleles that are dependent and independent of genetic architecture are stabilized in the plant genome and how methylation can regulate a transcription relative to its genomic location.
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Tobias PA, Schwessinger B, Deng CH, Wu C, Dong C, Sperschneider J, Jones A, Lou Z, Zhang P, Sandhu K, Smith GR, Tibbits J, Chagné D, Park RF. Austropuccinia psidii, causing myrtle rust, has a gigabase-sized genome shaped by transposable elements. G3 (BETHESDA, MD.) 2021; 11:jkaa015. [PMID: 33793741 PMCID: PMC8063080 DOI: 10.1093/g3journal/jkaa015] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 10/26/2020] [Indexed: 02/06/2023]
Abstract
Austropuccinia psidii, originating in South America, is a globally invasive fungal plant pathogen that causes rust disease on Myrtaceae. Several biotypes are recognized, with the most widely distributed pandemic biotype spreading throughout the Asia-Pacific and Oceania regions over the last decade. Austropuccinia psidii has a broad host range with more than 480 myrtaceous species. Since first detected in Australia in 2010, the pathogen has caused the near extinction of at least three species and negatively affected commercial production of several Myrtaceae. To enable molecular and evolutionary studies into A. psidii pathogenicity, we assembled a highly contiguous genome for the pandemic biotype. With an estimated haploid genome size of just over 1 Gb (gigabases), it is the largest assembled fungal genome to date. The genome has undergone massive expansion via distinct transposable element (TE) bursts. Over 90% of the genome is covered by TEs predominantly belonging to the Gypsy superfamily. These TE bursts have likely been followed by deamination events of methylated cytosines to silence the repetitive elements. This in turn led to the depletion of CpG sites in TEs and a very low overall GC content of 33.8%. Compared to other Pucciniales, the intergenic distances are increased by an order of magnitude indicating a general insertion of TEs between genes. Overall, we show how TEs shaped the genome evolution of A. psidii and provide a greatly needed resource for strategic approaches to combat disease spread.
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Affiliation(s)
- Peri A Tobias
- School of Life and Environmental Sciences, University of Sydney, Camperdown, NSW 2006, Australia
- Plant & Food Research Australia, SA 5064, Australia
| | - Benjamin Schwessinger
- Australia Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Cecilia H Deng
- The New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand
| | - Chen Wu
- The New Zealand Institute for Plant and Food Research Limited, Auckland 1142, New Zealand
| | - Chongmei Dong
- Plant Breeding Institute, University of Sydney, Narellan, NSW 2567, Australia
| | - Jana Sperschneider
- Biological Data Science Institute, The Australian National University, Canberra, ACT, 2600, Australia
| | - Ashley Jones
- Australia Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Zhenyan Lou
- Australia Research School of Biology, The Australian National University, Acton, ACT 2601, Australia
| | - Peng Zhang
- Plant Breeding Institute, University of Sydney, Narellan, NSW 2567, Australia
| | - Karanjeet Sandhu
- Plant Breeding Institute, University of Sydney, Narellan, NSW 2567, Australia
| | - Grant R Smith
- The New Zealand Institute for Plant and Food Research Limited, Christchurch 8140, New Zealand
| | - Josquin Tibbits
- Agriculture Victoria Department of Jobs, Precincts and Regions, Bundoora, VIC 3083, Australia
| | - David Chagné
- The New Zealand Institute for Plant & Food Research, Palmerston North 4442, New Zealand
| | - Robert F Park
- Plant Breeding Institute, University of Sydney, Narellan, NSW 2567, Australia
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Genetic and Methylome Variation in Turkish Brachypodium Distachyon Accessions Differentiate Two Geographically Distinct Subpopulations. Int J Mol Sci 2020; 21:ijms21186700. [PMID: 32933168 PMCID: PMC7556024 DOI: 10.3390/ijms21186700] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Revised: 09/04/2020] [Accepted: 09/09/2020] [Indexed: 12/13/2022] Open
Abstract
Brachypodium distachyon (Brachypodium) is a non-domesticated model grass species that can be used to test if variation in genetic sequence or methylation are linked to environmental differences. To assess this, we collected seeds from 12 sites within five climatically distinct regions of Turkey. Seeds from each region were grown under standardized growth conditions in the UK to preserve methylated sequence variation. At six weeks following germination, leaves were sampled and assessed for genomic and DNA methylation variation. In a follow-up experiment, phenomic approaches were used to describe plant growth and drought responses. Genome sequencing and population structure analysis suggested three ancestral clusters across the Mediterranean, two of which were geographically separated in Turkey into coastal and central subpopulations. Phenotypic analyses showed that the coastal subpopulation tended to exhibit relatively delayed flowering and the central, increased drought tolerance as indicated by reduced yellowing. Genome-wide methylation analyses in GpC, CHG and CHH contexts also showed variation which aligned with the separation into coastal and central subpopulations. The climate niche modelling of both subpopulations showed a significant influence from the “Precipitation in the Driest Quarter” on the central subpopulation and “Temperature of the Coldest Month” on the coastal subpopulation. Our work demonstrates genetic diversity and variation in DNA methylation in Turkish accessions of Brachypodium that may be associated with climate variables and the molecular basis of which will feature in ongoing analyses.
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