1
|
Chow HT, Mosher RA. Small RNA-mediated DNA methylation during plant reproduction. THE PLANT CELL 2023; 35:1787-1800. [PMID: 36651080 DOI: 10.1093/plcell/koad010] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/11/2023] [Accepted: 01/11/2023] [Indexed: 05/30/2023]
Abstract
Reproductive tissues are a rich source of small RNAs, including several classes of short interfering (si)RNAs that are restricted to this stage of development. In addition to RNA polymerase IV-dependent 24-nt siRNAs that trigger canonical RNA-directed DNA methylation, abundant reproductive-specific siRNAs are produced from companion cells adjacent to the developing germ line or zygote and may move intercellularly before inducing methylation. In some cases, these siRNAs are produced via non-canonical biosynthesis mechanisms or from sequences with little similarity to transposons. While the precise role of these siRNAs and the methylation they trigger is unclear, they have been implicated in specifying a single megaspore mother cell, silencing transposons in the male germ line, mediating parental dosage conflict to ensure proper endosperm development, hypermethylation of mature embryos, and trans-chromosomal methylation in hybrids. In this review, we summarize the current knowledge of reproductive siRNAs, including their biosynthesis, transport, and function.
Collapse
Affiliation(s)
- Hiu Tung Chow
- The School of Plant Sciences, The University of Arizona, Tucson, Arizona 85721-0036, USA
| | - Rebecca A Mosher
- The School of Plant Sciences, The University of Arizona, Tucson, Arizona 85721-0036, USA
| |
Collapse
|
2
|
Tonosaki K, Fujimoto R, Dennis ES, Raboy V, Osabe K. Will epigenetics be a key player in crop breeding? FRONTIERS IN PLANT SCIENCE 2022; 13:958350. [PMID: 36247549 PMCID: PMC9562705 DOI: 10.3389/fpls.2022.958350] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 09/12/2022] [Indexed: 06/16/2023]
Abstract
If food and feed production are to keep up with world demand in the face of climate change, continued progress in understanding and utilizing both genetic and epigenetic sources of crop variation is necessary. Progress in plant breeding has traditionally been thought to be due to selection for spontaneous DNA sequence mutations that impart desirable phenotypes. These spontaneous mutations can expand phenotypic diversity, from which breeders can select agronomically useful traits. However, it has become clear that phenotypic diversity can be generated even when the genome sequence is unaltered. Epigenetic gene regulation is a mechanism by which genome expression is regulated without altering the DNA sequence. With the development of high throughput DNA sequencers, it has become possible to analyze the epigenetic state of the whole genome, which is termed the epigenome. These techniques enable us to identify spontaneous epigenetic mutations (epimutations) with high throughput and identify the epimutations that lead to increased phenotypic diversity. These epimutations can create new phenotypes and the causative epimutations can be inherited over generations. There is evidence of selected agronomic traits being conditioned by heritable epimutations, and breeders may have historically selected for epiallele-conditioned agronomic traits. These results imply that not only DNA sequence diversity, but the diversity of epigenetic states can contribute to increased phenotypic diversity. However, since the modes of induction and transmission of epialleles and their stability differ from that of genetic alleles, the importance of inheritance as classically defined also differs. For example, there may be a difference between the types of epigenetic inheritance important to crop breeding and crop production. The former may depend more on longer-term inheritance whereas the latter may simply take advantage of shorter-term phenomena. With the advances in our understanding of epigenetics, epigenetics may bring new perspectives for crop improvement, such as the use of epigenetic variation or epigenome editing in breeding. In this review, we will introduce the role of epigenetic variation in plant breeding, largely focusing on DNA methylation, and conclude by asking to what extent new knowledge of epigenetics in crop breeding has led to documented cases of its successful use.
Collapse
Affiliation(s)
- Kaoru Tonosaki
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Japan
| | - Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University, Kobe, Japan
| | - Elizabeth S. Dennis
- Commonwealth Scientific and Industrial Research Organisation (CSIRO) Agriculture and Food, Canberra, ACT, Australia
- School of Life Sciences, Faculty of Science, University of Technology Sydney, Ultimo, NSW, Australia
| | - Victor Raboy
- Independent Researcher Portland, Portland, OR, United States
| | - Kenji Osabe
- Institute of Scientific and Industrial Research (SANKEN), Osaka University, Osaka, Japan
| |
Collapse
|
3
|
Mosher RA. Small RNAs on the move in male germ cells. Science 2021; 373:26-27. [PMID: 34210866 DOI: 10.1126/science.abj5020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Rebecca A Mosher
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721-0036, USA.
| |
Collapse
|
4
|
Chakraborty T, Kendall T, Grover JW, Mosher RA. Embryo CHH hypermethylation is mediated by RdDM and is autonomously directed in Brassica rapa. Genome Biol 2021; 22:140. [PMID: 33957938 PMCID: PMC8101221 DOI: 10.1186/s13059-021-02358-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Accepted: 04/21/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND RNA-directed DNA methylation (RdDM) initiates cytosine methylation in all contexts and maintains asymmetric CHH methylation. Mature plant embryos show one of the highest levels of CHH methylation, and it has been suggested that RdDM is responsible for this hypermethylation. Because loss of RdDM in Brassica rapa causes seed abortion, embryo methylation might play a role in seed development. RdDM is required in the maternal sporophyte, suggesting that small RNAs from the maternal sporophyte might translocate to the developing embryo, triggering DNA methylation that prevents seed abortion. This raises the question of whether embryo hypermethylation is autonomously regulated by the embryo itself or influenced by the maternal sporophyte. RESULTS Here, we demonstrate that B. rapa embryos are hypermethylated in both euchromatin and heterochromatin and that this process requires RdDM. Contrary to the current models, B. rapa embryo hypermethylation is not correlated with demethylation of the endosperm. We also show that maternal somatic RdDM is not sufficient for global embryo hypermethylation, and we find no compelling evidence for maternal somatic influence over embryo methylation at any locus. Decoupling of maternal and zygotic RdDM leads to successful seed development despite the loss of embryo CHH hypermethylation. CONCLUSIONS We conclude that embryo CHH hypermethylation is conserved, autonomously controlled, and not required for embryo development. Furthermore, maternal somatic RdDM, while required for seed development, does not directly influence embryo methylation patterns.
Collapse
Affiliation(s)
- Tania Chakraborty
- The School of Plant Sciences, The University of Arizona, Tucson, AZ 85721 USA
| | - Timmy Kendall
- The School of Plant Sciences, The University of Arizona, Tucson, AZ 85721 USA
| | - Jeffrey W. Grover
- Department of Molecular and Cellular Biology, The University of Arizona, Tucson, AZ 85721 USA
| | - Rebecca A. Mosher
- The School of Plant Sciences, The University of Arizona, Tucson, AZ 85721 USA
| |
Collapse
|
5
|
Bondada R, Somasundaram S, Marimuthu MP, Badarudeen MA, Puthiyaveedu VK, Maruthachalam R. Natural epialleles of Arabidopsis SUPERMAN display superwoman phenotypes. Commun Biol 2020; 3:772. [PMID: 33319840 PMCID: PMC7738503 DOI: 10.1038/s42003-020-01525-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Accepted: 11/25/2020] [Indexed: 01/07/2023] Open
Abstract
Epimutations are heritable changes in gene function due to loss or gain of DNA cytosine methylation or chromatin modifications without changes in the DNA sequence. Only a few natural epimutations displaying discernible phenotypes are documented in plants. Here, we report natural epimutations in the cadastral gene, SUPERMAN(SUP), showing striking phenotypes despite normal transcription, discovered in a natural tetraploid, and subsequently in eleven diploid Arabidopsis genetic accessions. This natural lois lane(lol) epialleles behave as recessive mendelian alleles displaying a spectrum of silent to strong superwoman phenotypes affecting only the carpel whorl, in contrast to semi-dominant superman or supersex features manifested by induced epialleles which affect both stamen and carpel whorls. Despite its unknown origin, natural lol epialleles are subjected to the same epigenetic regulation as induced clk epialleles. The existence of superwoman epialleles in diverse wild populations is interpreted in the light of the evolution of unisexuality in plants. Ramesh Bondada et al. report natural epimutations in the Arabidopsis SUPERMAN gene from tetraploid and diploid accessions. The existence of these epialleles in diverse wild populations have the potential to shed light on the evolution of unisexuality in plants.
Collapse
Affiliation(s)
- Ramesh Bondada
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Vithura, Kerala, 695551, India
| | - Saravanakumar Somasundaram
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Vithura, Kerala, 695551, India
| | | | - Mohammed Afsal Badarudeen
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Vithura, Kerala, 695551, India
| | - Vaishak Kanjirakol Puthiyaveedu
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Vithura, Kerala, 695551, India
| | - Ravi Maruthachalam
- School of Biology, Indian Institute of Science Education and Research (IISER)-Thiruvananthapuram, Vithura, Kerala, 695551, India.
| |
Collapse
|
6
|
Chow HT, Chakraborty T, Mosher RA. RNA-directed DNA Methylation and sexual reproduction: expanding beyond the seed. CURRENT OPINION IN PLANT BIOLOGY 2020; 54:11-17. [PMID: 31881293 DOI: 10.1016/j.pbi.2019.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 05/12/2023]
Abstract
Two trends are changing our understanding of RNA-directed DNA methylation. In model systems like Arabidopsis, tissue-specific analysis of DNA methylation is uncovering dynamic changes in methylation during sexual reproduction and unraveling the contribution of maternal and paternal epigenomes to the developing embryo. These studies indicate that RNA-directed DNA Methylation might be important for mediating balance between maternal and paternal contributions to the endosperm. At the same time, researchers are moving beyond Arabidopsis to illuminate the ancestral role of RdDM in non-flowering plants that lack an endosperm, suggesting that RdDM might play a broader role in sexual reproduction.
Collapse
Affiliation(s)
- Hiu Tung Chow
- The School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, United States
| | - Tania Chakraborty
- The School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, United States
| | - Rebecca A Mosher
- The School of Plant Sciences, The University of Arizona, Tucson, AZ 85721, United States.
| |
Collapse
|
7
|
Mehraj H, Kawanabe T, Shimizu M, Miyaji N, Akter A, Dennis ES, Fujimoto R. In Arabidopsis thaliana Heterosis Level Varies among Individuals in an F 1 Hybrid Population. PLANTS 2020; 9:plants9040414. [PMID: 32230994 PMCID: PMC7238264 DOI: 10.3390/plants9040414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 03/23/2020] [Accepted: 03/23/2020] [Indexed: 11/28/2022]
Abstract
Heterosis or hybrid vigour is a phenomenon in which hybrid progeny exhibit superior yield and biomass to parental lines and has been used to breed F1 hybrid cultivars in many crops. A similar level of heterosis in all F1 individuals is expected as they are genetically identical. However, we found variation in rosette size in individual F1 plants from a cross between C24 and Columbia-0 accessions of Arabidopsis thaliana. Big-sized F1 plants had 26.1% larger leaf area in the first and second leaves than medium-sized F1 plants at 14 days after sowing in spite of the identical genetic background. We identified differentially expressed genes between big- and medium-sized F1 plants by microarray; genes involved in the category of stress response were overrepresented. We made transgenic plants overexpressing 21 genes, which were differentially expressed between the two size classes, and some lines had increased plant size at 14 or 21 days after sowing but not at all time points during development. Change of expression levels in stress-responsive genes among individual F1 plants could generate the variation in plant size of individual F1 plants in A. thaliana.
Collapse
Affiliation(s)
- Hasan Mehraj
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan; (H.M.); (N.M.); (A.A.)
| | - Takahiro Kawanabe
- School of Agriculture, Tokai University, Toroku, Higashi-ku, Kumamoto 862-8652, Japan
- Correspondence: (T.K.); (R.F.)
| | - Motoki Shimizu
- Iwate Biotechnology Research Center, Narita, Kitakami, Iwate 024-0003, Japan;
| | - Naomi Miyaji
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan; (H.M.); (N.M.); (A.A.)
| | - Ayasha Akter
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan; (H.M.); (N.M.); (A.A.)
- Department of Horticulture, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh
| | - Elizabeth S. Dennis
- CSIRO Agriculture and Food, Canberra, ACT 2601, Australia;
- University of Technology, Sydney, PO Box 123, Broadway, NSW 2007, Australia
| | - Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe 657-8501, Japan; (H.M.); (N.M.); (A.A.)
- Correspondence: (T.K.); (R.F.)
| |
Collapse
|
8
|
Borgognone A, Castanera R, Morselli M, López-Varas L, Rubbi L, Pisabarro AG, Pellegrini M, Ramírez L. Transposon-associated epigenetic silencing during Pleurotus ostreatus life cycle. DNA Res 2018; 25:451-464. [PMID: 29893819 PMCID: PMC6191308 DOI: 10.1093/dnares/dsy016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 05/15/2018] [Indexed: 12/14/2022] Open
Abstract
Transposable elements constitute an important fraction of eukaryotic genomes. Given their mutagenic potential, host-genomes have evolved epigenetic defense mechanisms to limit their expansion. In fungi, epigenetic modifications have been widely studied in ascomycetes, although we lack a global picture of the epigenetic landscape in basidiomycetes. In this study, we analysed the genome-wide epigenetic and transcriptional patterns of the white-rot basidiomycete Pleurotus ostreatus throughout its life cycle. Our results performed by using high-throughput sequencing analyses revealed that strain-specific DNA methylation profiles are primarily involved in the repression of transposon activity and suggest that 21 nt small RNAs play a key role in transposon silencing. Furthermore, we provide evidence that transposon-associated DNA methylation, but not sRNA production, is directly involved in the silencing of genes surrounded by transposons. Remarkably, we found that nucleus-specific methylation levels varied in dikaryotic strains sharing identical genetic complement but different subculture conditions. Finally, we identified key genes activated in the fruiting process through the comparative analysis of transcriptomes. This study provides an integrated picture of epigenetic defense mechanisms leading to the transcriptional silencing of transposons and surrounding genes in basidiomycetes. Moreover, our findings suggest that transcriptional but not methylation reprogramming triggers fruitbody development in P. ostreatus.
Collapse
Affiliation(s)
- Alessandra Borgognone
- Genetics and Microbiology Research Group, Department of Agrarian Production, Public University of Navarre, Pamplona, Navarre, Spain
| | - Raúl Castanera
- Genetics and Microbiology Research Group, Department of Agrarian Production, Public University of Navarre, Pamplona, Navarre, Spain
| | - Marco Morselli
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, USA
- Institute for Genomics and Proteomics, UCLA-U.S. Department of Energy (DOE), University of California, Los Angeles, USA
| | - Leticia López-Varas
- Genetics and Microbiology Research Group, Department of Agrarian Production, Public University of Navarre, Pamplona, Navarre, Spain
| | - Liudmilla Rubbi
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, USA
| | - Antonio G Pisabarro
- Genetics and Microbiology Research Group, Department of Agrarian Production, Public University of Navarre, Pamplona, Navarre, Spain
| | - Matteo Pellegrini
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, USA
- Institute for Genomics and Proteomics, UCLA-U.S. Department of Energy (DOE), University of California, Los Angeles, USA
| | - Lucía Ramírez
- Genetics and Microbiology Research Group, Department of Agrarian Production, Public University of Navarre, Pamplona, Navarre, Spain
| |
Collapse
|
9
|
Itabashi E, Osabe K, Fujimoto R, Kakizaki T. Epigenetic regulation of agronomical traits in Brassicaceae. PLANT CELL REPORTS 2018; 37:87-101. [PMID: 29058037 DOI: 10.1007/s00299-017-2223-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 10/05/2017] [Indexed: 05/08/2023]
Abstract
Epigenetic regulation, covalent modification of DNA and changes in histone proteins are closely linked to plant development and stress response through flexibly altering the chromatin structure to regulate gene expression. In this review, we will illustrate the importance of epigenetic influences by discussing three agriculturally important traits of Brassicaceae. (1) Vernalization, an acceleration of flowering by prolonged cold exposure regulated through epigenetic silencing of a central floral repressor, FLOWERING LOCUS C. This is associated with cold-dependent repressive histone mark accumulation, which confers competency of consequence vegetative-to-reproductive phase transition. (2) Hybrid vigor, in which an F1 hybrid shows superior performance to the parental lines. Combination of distinct epigenomes with different DNA methylation states between parental lines is important for increase in growth rate in a hybrid progeny. This is independent of siRNA-directed DNA methylation but dependent on the chromatin remodeler DDM1. (3) Self-incompatibility, a reproductive mating system to prevent self-fertilization. This is controlled by the S-locus consisting of SP11 and SRK which are responsible for self/non-self recognition. Because self-incompatibility in Brassicaceae is sporophytically controlled, there are dominance relationships between S haplotypes in the stigma and pollen. The dominance relationships in the pollen rely on de novo DNA methylation at the promoter region of a recessive allele, which is triggered by siRNA production from a flanking region of a dominant allele.
Collapse
Affiliation(s)
- Etsuko Itabashi
- Institute of Vegetable and Floriculture Science, NARO, Kusawa, Ano, Tsu, Mie, 514-2392, Japan.
| | - Kenji Osabe
- Okinawa Institute of Science and Technology Graduate University, Onna-son, Kunigami, Okinawa, 904-0495, Japan
| | - Ryo Fujimoto
- Graduate School of Agricultural Science, Kobe University, Rokkodai, Nada-ku, Kobe, 657-8501, Japan
| | - Tomohiro Kakizaki
- Institute of Vegetable and Floriculture Science, NARO, Kusawa, Ano, Tsu, Mie, 514-2392, Japan
| |
Collapse
|
10
|
Day K, Waite LL, Alonso A, Irvin MR, Zhi D, Thibeault KS, Aslibekyan S, Hidalgo B, Borecki IB, Ordovas JM, Arnett DK, Tiwari HK, Absher DM. Heritable DNA Methylation in CD4+ Cells among Complex Families Displays Genetic and Non-Genetic Effects. PLoS One 2016; 11:e0165488. [PMID: 27792787 PMCID: PMC5085095 DOI: 10.1371/journal.pone.0165488] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 10/12/2016] [Indexed: 12/20/2022] Open
Abstract
DNA methylation at CpG sites is both heritable and influenced by environment, but the relative contributions of each to DNA methylation levels are unclear. We conducted a heritability analysis of CpG methylation in human CD4+ cells across 975 individuals from 163 families in the Genetics of Lipid-lowering Drugs and Diet Network (GOLDN). Based on a broad-sense heritability (H2) value threshold of 0.4, we identified 20,575 highly heritable CpGs among the 174,445 most variable autosomal CpGs (SD > 0.02). Tests for associations of heritable CpGs with genotype at 2,145,360 SNPs using 717 of 975 individuals showed that ~74% were cis-meQTLs (< 1 Mb away from the CpG), 6% of CpGs exhibited trans-meQTL associations (>1 Mb away from the CpG or located on a different chromosome), and 20% of CpGs showed no strong significant associations with genotype (based on a p-value threshold of 1e-7). Genes proximal to the genotype independent heritable CpGs were enriched for functional terms related to regulation of T cell activation. These CpGs were also among those that distinguished T cells from other blood cell lineages. Compared to genes proximal to meQTL-associated heritable CpGs, genotype independent heritable CpGs were moderately enriched in the same genomic regions that escape erasure during primordial germ cell development and could carry potential for generational transmission.
Collapse
Affiliation(s)
- Kenneth Day
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama, United States of America
| | - Lindsay L. Waite
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama, United States of America
- University of Alabama at Birmingham, School of Public Health, Department of Biostatistics, Birmingham, Alabama, United States of America
| | - Arnald Alonso
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama, United States of America
| | - Marguerite R. Irvin
- University of Alabama at Birmingham, School of Public Health, Department of Epidemiology, Birmingham, Alabama, United States of America
| | - Degui Zhi
- University of Alabama at Birmingham, School of Public Health, Department of Biostatistics, Birmingham, Alabama, United States of America
| | - Krista S. Thibeault
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama, United States of America
| | - Stella Aslibekyan
- University of Alabama at Birmingham, School of Public Health, Department of Epidemiology, Birmingham, Alabama, United States of America
| | - Bertha Hidalgo
- University of Alabama at Birmingham, School of Public Health, Department of Biostatistics, Birmingham, Alabama, United States of America
| | - Ingrid B. Borecki
- Washington University, Division of Statistical Genomics, St. Louis, Missouri, United States of America
| | - Jose M. Ordovas
- Tufts University, Jean Mayer USDA Human Nutrition Research Center on Aging, Boston, Massachusetts, United States of America
- IMDEA-Food, Madrid, Spain
| | - Donna K. Arnett
- University of Alabama at Birmingham, School of Public Health, Department of Epidemiology, Birmingham, Alabama, United States of America
| | - Hemant K. Tiwari
- University of Alabama at Birmingham, School of Public Health, Department of Biostatistics, Birmingham, Alabama, United States of America
| | - Devin M. Absher
- HudsonAlpha Institute for Biotechnology, Huntsville, Alabama, United States of America
- * E-mail:
| |
Collapse
|
11
|
Twenty-four-nucleotide siRNAs produce heritable trans-chromosomal methylation in F1 Arabidopsis hybrids. Proc Natl Acad Sci U S A 2016; 113:E6895-E6902. [PMID: 27791153 DOI: 10.1073/pnas.1613623113] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hybrid Arabidopsis plants undergo epigenetic reprogramming producing decreased levels of 24-nt siRNAs and altered patterns of DNA methylation that can affect gene expression. Driving the changes in methylation are the processes trans-chromosomal methylation (TCM) and trans-chromosomal demethylation (TCdM). In TCM/TCdM the methylation state of one allele is altered to resemble the other allele. We show that Pol IV-dependent sRNAs are required to establish TCM events. The changes in DNA methylation and the associated changes in sRNA levels in the F1 hybrid can be maintained in subsequent generations and affect hundreds of regions in the F2 epigenome. The inheritance of these altered epigenetic states varies in F2 individuals, resulting in individuals with genetically identical loci displaying different epigenetic states and gene expression profiles. The change in methylation at these regions is associated with the presence of sRNAs. Loci without any sRNA activity can have altered methylation states, suggesting that a sRNA-independent mechanism may also contribute to the altered methylation state of the F1 and F2 generations.
Collapse
|
12
|
Methylation interactions in Arabidopsis hybrids require RNA-directed DNA methylation and are influenced by genetic variation. Proc Natl Acad Sci U S A 2016; 113:E4248-56. [PMID: 27382183 DOI: 10.1073/pnas.1607851113] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
DNA methylation is a conserved epigenetic mark in plants and many animals. How parental alleles interact in progeny to influence the epigenome is poorly understood. We analyzed the DNA methylomes of Arabidopsis Col and C24 ecotypes, and their hybrid progeny. Hybrids displayed nonadditive DNA methylation levels, termed methylation interactions, throughout the genome. Approximately 2,500 methylation interactions occurred at regions where parental DNA methylation levels are similar, whereas almost 1,000 were at differentially methylated regions in parents. Methylation interactions were characterized by an abundance of 24-nt small interfering RNAs. Furthermore, dysfunction of the RNA-directed DNA methylation pathway abolished methylation interactions but did not affect the increased biomass observed in hybrid progeny. Methylation interactions correlated with altered genetic variation within the genome, suggesting that they may play a role in genome evolution.
Collapse
|
13
|
Arabidopsis MSH1 mutation alters the epigenome and produces heritable changes in plant growth. Nat Commun 2015; 6:6386. [PMID: 25722057 PMCID: PMC4351625 DOI: 10.1038/ncomms7386] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Accepted: 01/26/2015] [Indexed: 01/27/2023] Open
Abstract
Plant phenotypes respond to environmental change, an adaptive capacity that is at least partly transgenerational. However, epigenetic components of this interplay are difficult to measure. Depletion of the nuclear-encoded protein MSH1 causes dramatic and heritable changes in plant development, and here we show that crossing these altered plants with isogenic wild type produces epi-lines with heritable, enhanced growth vigour. Pericentromeric DNA hypermethylation occurs in a subset of msh1 mutants, indicative of heightened transposon repression, while enhanced growth epi-lines show large chromosomal segments of differential CG methylation, reflecting genome-wide reprogramming. When seedlings are treated with 5-azacytidine, root growth of epi-lines is restored to wild-type levels, implicating hypermethylation in enhanced growth. Grafts of wild-type floral stems to mutant rosettes produce progeny with enhanced growth and altered CG methylation strikingly similar to epi-lines, indicating a mobile signal when MSH1 is downregulated, and confirming the programmed nature of methylome and phenotype changes. Suppression of MutS HOMOLOGUE 1 (MSH1), a plant protein targeted to mitochondria and plastids, causes a variety of phenotypes. Here Virdi et al. show that MSH1 depletion in Arabidopsis results in heritable changes in nuclear DNA methylation, which can lead to enhanced growth vigour.
Collapse
|
14
|
Groszmann M, Gonzalez-Bayon R, Greaves IK, Wang L, Huen AK, Peacock WJ, Dennis ES. Intraspecific Arabidopsis hybrids show different patterns of heterosis despite the close relatedness of the parental genomes. PLANT PHYSIOLOGY 2014; 166:265-80. [PMID: 25073707 PMCID: PMC4149712 DOI: 10.1104/pp.114.243998] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2014] [Accepted: 07/24/2014] [Indexed: 05/03/2023]
Abstract
Heterosis is important for agriculture; however, little is known about the mechanisms driving hybrid vigor. Ultimately, heterosis depends on the interactions of specific alleles and epialleles provided by the parents, which is why hybrids can exhibit different levels of heterosis, even within the same species. We characterize the development of several intraspecific Arabidopsis (Arabidopsis thaliana) F1 hybrids that show different levels of heterosis at maturity. We identify several phases of heterosis beginning during embryogenesis and culminating in a final phase of vegetative maturity and seed production. During each phase, the hybrids show different levels and patterns of growth, despite the close relatedness of the parents. For instance, during the vegetative phases, the hybrids develop larger leaves than the parents to varied extents, and they do so by exploiting increases in cell size and cell numbers in different ratios. Consistent with this finding, we observed changes in the expression of genes known to regulate leaf size in developing rosettes of the hybrids, with the patterns of altered expression differing between combinations. The data show that heterosis is dependent on changes in development throughout the growth cycle of the hybrid, with the traits of mature vegetative biomass and reproductive yield as cumulative outcomes of heterosis at different levels, tissues, and times of development.
Collapse
Affiliation(s)
- Michael Groszmann
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.)
| | - Rebeca Gonzalez-Bayon
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.)
| | - Ian K Greaves
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.)
| | - Li Wang
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.)
| | - Amanda K Huen
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.)
| | - W James Peacock
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.)
| | - Elizabeth S Dennis
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Canberra, Australian Capital Territory 2600, Australia (M.G., R.G.-B., I.K.G., L.W., A.K.H., W.J.P., E.S.D.); andUniversity of Technology, Sydney, New South Wales 2007, Australia (E.S.D., W.J.P.)
| |
Collapse
|
15
|
Plongthongkum N, van Eijk KR, de Jong S, Wang T, Sul JH, Boks MPM, Kahn RS, Fung HL, Ophoff RA, Zhang K. Characterization of genome-methylome interactions in 22 nuclear pedigrees. PLoS One 2014; 9:e99313. [PMID: 25019935 PMCID: PMC4096397 DOI: 10.1371/journal.pone.0099313] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2013] [Accepted: 05/13/2014] [Indexed: 12/19/2022] Open
Abstract
Genetic polymorphisms can shape the global landscape of DNA methylation, by either changing substrates for DNA methyltransferases or altering the DNA binding affinity of cis-regulatory proteins. The interactions between CpG methylation and genetic polymorphisms have been previously investigated by methylation quantitative trait loci (mQTL) and allele-specific methylation (ASM) analysis. However, it remains unclear whether these approaches can effectively and comprehensively identify all genetic variants that contribute to the inter-individual variation of DNA methylation levels. Here we used three independent approaches to systematically investigate the influence of genetic polymorphisms on variability in DNA methylation by characterizing the methylation state of 96 whole blood samples in 52 parent-child trios from 22 nuclear pedigrees. We performed targeted bisulfite sequencing with padlock probes to quantify the absolute DNA methylation levels at a set of 411,800 CpG sites in the human genome. With mid-parent offspring analysis (MPO), we identified 10,593 CpG sites that exhibited heritable methylation patterns, among which 70.1% were SNPs directly present in methylated CpG dinucleotides. We determined the mQTL analysis identified 49.9% of heritable CpG sites for which regulation occurred in a distal cis-regulatory manner, and that ASM analysis was only able to identify 5%. Finally, we identified hundreds of clusters in the human genome for which the degree of variation of CpG methylation, as opposed to whether or not CpG sites were methylated, was associated with genetic polymorphisms, supporting a recent hypothesis on the genetic influence of phenotypic plasticity. These results show that cis-regulatory SNPs identified by mQTL do not comprise the full extent of heritable CpG methylation, and that ASM appears overall unreliable. Overall, the extent of genome-methylome interactions is well beyond what is detectible with the commonly used mQTL and ASM approaches, and is likely to include effects on plasticity.
Collapse
Affiliation(s)
- Nongluk Plongthongkum
- Department of Bioengineering, University of California San Diego, La Jolla, California, United States of America
| | - Kristel R. van Eijk
- Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Simone de Jong
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Behavior, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, United States of America
| | - Tina Wang
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Behavior, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, United States of America
| | - Jae Hoon Sul
- Department of Computer Science, University of California Los Angeles, Los Angeles, California, United States of America
| | - Marco P. M. Boks
- Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - René S. Kahn
- Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Ho-Lim Fung
- Department of Bioengineering, University of California San Diego, La Jolla, California, United States of America
| | - Roel A. Ophoff
- Center for Neurobehavioral Genetics, Semel Institute for Neuroscience and Behavior, David Geffen School of Medicine at the University of California Los Angeles, Los Angeles, California, United States of America
- Department of Psychiatry, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Kun Zhang
- Department of Bioengineering, University of California San Diego, La Jolla, California, United States of America
| |
Collapse
|
16
|
Allele-specific DNA methylation analyses associated with siRNAs in Arabidopsis hybrids. SCIENCE CHINA-LIFE SCIENCES 2014; 57:519-25. [DOI: 10.1007/s11427-014-4629-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 09/18/2013] [Indexed: 10/25/2022]
|
17
|
Inheritance of Trans Chromosomal Methylation patterns from Arabidopsis F1 hybrids. Proc Natl Acad Sci U S A 2014; 111:2017-22. [PMID: 24449910 DOI: 10.1073/pnas.1323656111] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Hybridization in plants leads to transinteractions between the parental genomes and epigenomes that can result in changes to both 24 nt siRNA and cytosine methylation ((m)C) levels in the hybrid. In Arabidopsis the principle processes altering the hybrid methylome are Trans Chromosomal Methylation (TCM) and Trans Chromosomal deMethylation (TCdM) in which the (m)C pattern of a genomic segment attains the same (m)C pattern of the corresponding segment on the other parental chromosome. We examined two loci that undergo TCM/TCdM in the Arabidopsis C24/Landsberg erecta (Ler) F1 hybrids, which show patterns of inheritance dependent on the properties of the particular donor and recipient chromosomal segments. At At1g64790 the TCM- and TCdM-derived (m)C patterns are maintained in the F2 generation but are transmitted in outcrosses or backcrosses only by the C24 genomic segment. At a region between and adjacent to At3g43340 and At3g43350, the originally unmethylated Ler genomic segment receives the C24 (m)C pattern in the F1, which is then maintained in backcross plants independent of the presence of the parental C24 segment. In backcrosses to an unmethylated Ler allele, the newly methylated F1 Ler segment may act as a TCM source in a process comparable to paramutation in maize. TCM-derived (m)C patterns are associated with reduced expression of both At3g43340 and At3g43350 in F1 and F2 plants, providing support for such events influencing the transcriptome. The inheritance of the F1 (m)C patterns and the segregation of other genetic and epigenetic determinants may contribute to the reduced hybrid vigor in the F2 and subsequent generations.
Collapse
|
18
|
The role of epigenetics in hybrid vigour. Trends Genet 2013; 29:684-90. [PMID: 23953922 DOI: 10.1016/j.tig.2013.07.004] [Citation(s) in RCA: 108] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Revised: 07/04/2013] [Accepted: 07/22/2013] [Indexed: 12/23/2022]
Abstract
Hybrid vigour, or heterosis, refers to the increased yield and biomass of hybrid offspring relative to the parents. Although this has been exploited in plants for agriculture and horticulture, the molecular and cellular mechanisms underlying hybrid vigour are largely unknown. Genetic analyses show that there are a large number of quantitative trait loci (QTLs) that contribute to the heterotic phenotype, indicating that it is a complex phenomenon. Gene expression in hybrids is regulated by the interactions of the two parental epigenetic systems and the underlying genomes. Increasing understanding of the interplay of small RNA (sRNA) molecules, DNA methylation, and histone marks provides new opportunities to define the basis of hybrid vigour and to understand why F1 heterosis is not passed on to subsequent generations. We discuss recent findings that suggest the existence of several pathways that alter DNA methylation patterns, which may lead to transcriptional changes resulting in the heterotic phenotype.
Collapse
|
19
|
He G, He H, Deng XW. Epigenetic Variations in Plant Hybrids and Their Potential Roles in Heterosis. J Genet Genomics 2013; 40:205-10. [DOI: 10.1016/j.jgg.2013.03.011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2013] [Revised: 03/28/2013] [Accepted: 03/28/2013] [Indexed: 01/09/2023]
|