1
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Chernomas G, Griswold CK. Deleterious mutation/epimutation-selection balance with and without inbreeding: a population (epi)genetics model. Genetics 2024; 227:iyae080. [PMID: 38733620 PMCID: PMC11228854 DOI: 10.1093/genetics/iyae080] [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: 03/26/2024] [Revised: 04/30/2024] [Accepted: 05/02/2024] [Indexed: 05/13/2024] Open
Abstract
Epigenetics in the form of DNA methylation and other processes is an established property of genotypes and a focus of empirical research. Yet, there remain fundamental gaps in the evolutionary theory of epigenetics. To support a comprehensive understanding of epigenetics, this paper investigates theoretically the combined effects of deleterious mutation and epimutation with and without inbreeding. Both spontaneous epimutation and paramutation are considered to cover a broader range of epigenetic phenomena. We find that inbreeding generally reduces the amount of segregating deleterious genetic and epigenetic variation at equilibrium, although interestingly inbreeding can also increase the amount of deleterious genetic or epigenetic variation. Furthermore, we also demonstrate that epimutation indirectly can cause increased or decreased deleterious genetic variation at equilibrium relative to classic expectations, which is particularly evident when paramutation is occurring. With the addition of deleterious epimutation, there may be significantly increased purging of deleterious variation in more inbred populations and a significantly increased amount of segregating deleterious variation in more outbred populations, with notable exceptions.
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Affiliation(s)
- Gregory Chernomas
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Cortland K Griswold
- Department of Integrative Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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2
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Deans NC, Talbot JERB, Li M, Sáez-González C, Hövel I, Heavens D, Stam M, Hollick JB. Paramutation at the maize pl1 locus is associated with RdDM activity at distal tandem repeats. PLoS Genet 2024; 20:e1011296. [PMID: 38814980 PMCID: PMC11166354 DOI: 10.1371/journal.pgen.1011296] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 06/11/2024] [Accepted: 05/08/2024] [Indexed: 06/01/2024] Open
Abstract
Exceptions to Mendelian inheritance often highlight novel chromosomal behaviors. The maize Pl1-Rhoades allele conferring plant pigmentation can display inheritance patterns deviating from Mendelian expectations in a behavior known as paramutation. However, the chromosome features mediating such exceptions remain unknown. Here we show that small RNA production reflecting RNA polymerase IV function within a distal downstream set of five tandem repeats is coincident with meiotically-heritable repression of the Pl1-Rhoades transcription unit. A related pl1 haplotype with three, but not one with two, repeat units also displays the trans-homolog silencing typifying paramutations. 4C interactions, CHD3a-dependent small RNA profiles, nuclease sensitivity, and polyadenylated RNA levels highlight a repeat subregion having regulatory potential. Our comparative and mutant analyses show that transcriptional repression of Pl1-Rhoades correlates with 24-nucleotide RNA production and cytosine methylation at this subregion indicating the action of a specific DNA-dependent RNA polymerase complex. These findings support a working model in which pl1 paramutation depends on trans-chromosomal RNA-directed DNA methylation operating at a discrete cis-linked and copy-number-dependent transcriptional regulatory element.
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Affiliation(s)
- Natalie C. Deans
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- Centers for Applied Plant Sciences and RNA Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Joy-El R. B. Talbot
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- Department of Molecular and Cell Biology, University of California Berkeley, Berkeley, California, United States of America
| | - Mowei Li
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- Centers for Applied Plant Sciences and RNA Biology, The Ohio State University, Columbus, Ohio, United States of America
| | - Cristian Sáez-González
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Iris Hövel
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Amsterdam, The Netherlands
| | | | - Maike Stam
- Swammerdam Institute for Life Sciences, Universiteit van Amsterdam, Amsterdam, The Netherlands
| | - Jay B. Hollick
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- Centers for Applied Plant Sciences and RNA Biology, The Ohio State University, Columbus, Ohio, United States of America
- Department of Plant and Microbial Biology, University of California, Berkeley, California, United States of America
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3
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Bradamante G, Nguyen VH, Incarbone M, Meir Z, Bente H, Donà M, Lettner N, Scheid OM, Gutzat R. Two ARGONAUTE proteins loaded with transposon-derived small RNAs are associated with the reproductive cell lineage in Arabidopsis. THE PLANT CELL 2024; 36:863-880. [PMID: 38060984 PMCID: PMC10980394 DOI: 10.1093/plcell/koad295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 11/23/2023] [Indexed: 04/01/2024]
Abstract
In sexually propagating organisms, genetic, and epigenetic mutations are evolutionarily relevant only if they occur in the germline and are hence transmitted to the next generation. In contrast to most animals, plants are considered to lack an early segregating germline, implying that somatic cells can contribute genetic information to progeny. Here we demonstrate that 2 ARGONAUTE proteins, AGO5 and AGO9, mark cells associated with sexual reproduction in Arabidopsis (Arabidopsis thaliana) throughout development. Both AGOs are loaded with dynamically changing small RNA populations derived from highly methylated, pericentromeric, long transposons. Sequencing of single stem cell nuclei revealed that many of these transposons are co-expressed within an AGO5/9 expression domain in the shoot apical meristem (SAM). Co-occurrence of transposon expression and specific ARGONAUTE (AGO) expression in the SAM is reminiscent of germline features in animals and supports the existence of an early segregating germline in plants. Our results open the path to investigating transposon biology and epigenome dynamics at cellular resolution in the SAM stem cell niche.
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Affiliation(s)
- Gabriele Bradamante
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Vu Hoang Nguyen
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Marco Incarbone
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Zohar Meir
- Faculty of Mathematics and Computer Science & Department of Plant and Environmental Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Heinrich Bente
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Mattia Donà
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Nicole Lettner
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Ortrun Mittelsten Scheid
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Ruben Gutzat
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
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4
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Sidorenko LV, Chandler VL, Wang X, Peterson T. Transcribed enhancer sequences are required for maize p1 paramutation. Genetics 2024; 226:iyad178. [PMID: 38169343 PMCID: PMC10763531 DOI: 10.1093/genetics/iyad178] [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: 11/14/2021] [Accepted: 08/27/2023] [Indexed: 01/05/2024] Open
Abstract
Paramutation is a transfer of heritable silencing states between interacting endogenous alleles or between endogenous alleles and homologous transgenes. Prior results demonstrated that paramutation occurs at the P1-rr (red pericarp and red cob) allele of the maize p1 (pericarp color 1) gene when exposed to a transgene containing a 1.2-kb enhancer fragment (P1.2) of P1-rr. The paramutable P1-rr allele undergoes transcriptional silencing resulting in a paramutant light-pigmented P1-rr' state. To define more precisely the sequences required to elicit paramutation, the P1.2 fragment was further subdivided, and the fragments transformed into maize plants and crossed with P1-rr. Analysis of the progeny plants showed that the sequences required for paramutation are located within a ∼600-bp segment of P1.2 and that this segment overlaps with a previously identified enhancer that is present in 4 direct repeats in P1-rr. The paramutagenic segment is transcribed in both the expressed P1-rr and the silenced P1-rr'. Transcription is sensitive to α-amanitin, indicating that RNA polymerase II mediates most of the transcription of this sequence. Although transcription within the paramutagenic sequence was similar in all tested genotypes, small RNAs were more abundant in the silenced P1-rr' epiallele relative to the expressed P1-rr allele. In agreement with prior results indicating the association of RNA-mediated DNA methylation in p1 paramutation, DNA blot analyses detected increased cytosine methylation of the paramutant P1-rr' sequences homologous to the transgenic P1.2 subfragments. Together these results demonstrate that the P1-rr enhancer repeats mediate p1 paramutation.
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Affiliation(s)
- Lyudmila V Sidorenko
- Department of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA
- Corteva Agriscience, 7300 NW 62nd Ave, Johnston, IA 50131, USA
| | - Vicki L Chandler
- Department of Plant Sciences, The University of Arizona, Tucson, AZ 85721, USA
- Minerva University, 14 Mint Plaza, Suite 300, San Francisco, CA 94103, USA
| | - Xiujuan Wang
- Corteva Agriscience, 7300 NW 62nd Ave, Johnston, IA 50131, USA
- Department of Genetics, Development, and Cellular Biology, Department of Agronomy, Iowa State University, Ames, IA 50010, USA
| | - Thomas Peterson
- Department of Genetics, Development, and Cellular Biology, Department of Agronomy, Iowa State University, Ames, IA 50010, USA
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5
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Yew CL, Tsuchimatsu T, Shimizu-Inatsugi R, Yasuda S, Hatakeyama M, Kakui H, Ohta T, Suwabe K, Watanabe M, Takayama S, Shimizu KK. Dominance in self-compatibility between subgenomes of allopolyploid Arabidopsis kamchatica shown by transgenic restoration of self-incompatibility. Nat Commun 2023; 14:7618. [PMID: 38030610 PMCID: PMC10687001 DOI: 10.1038/s41467-023-43275-2] [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: 11/28/2022] [Accepted: 11/03/2023] [Indexed: 12/01/2023] Open
Abstract
The evolutionary transition to self-compatibility facilitates polyploid speciation. In Arabidopsis relatives, the self-incompatibility system is characterized by epigenetic dominance modifiers, among which small RNAs suppress the expression of a recessive SCR/SP11 haplogroup. Although the contribution of dominance to polyploid self-compatibility is speculated, little functional evidence has been reported. Here we employ transgenic techniques to the allotetraploid plant A. kamchatica. We find that when the dominant SCR-B is repaired by removing a transposable element insertion, self-incompatibility is restored. This suggests that SCR was responsible for the evolution of self-compatibility. By contrast, the reconstruction of recessive SCR-D cannot restore self-incompatibility. These data indicate that the insertion in SCR-B conferred dominant self-compatibility to A. kamchatica. Dominant self-compatibility supports the prediction that dominant mutations increasing selfing rate can pass through Haldane's sieve against recessive mutations. The dominance regulation between subgenomes inherited from progenitors contrasts with previous studies on novel epigenetic mutations at polyploidization termed genome shock.
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Grants
- JPMJCR16O3 MEXT | JST | Core Research for Evolutional Science and Technology (CREST)
- 310030_212551, 31003A_182318, 31003A_159767, 31003A_140917, 310030_212674 Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (Swiss National Science Foundation)
- 310030_212674 Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung (Swiss National Science Foundation)
- grant numbers 16H06469, 16K21727, 22H02316, 22K21352, 22H05172 and 22H05179 MEXT | Japan Society for the Promotion of Science (JSPS)
- Postdoctoral fellowship, 22K21352, 16H06467 and 17H05833 MEXT | Japan Society for the Promotion of Science (JSPS)
- 21H02162, 22H05172 and 22H05179 MEXT | Japan Society for the Promotion of Science (JSPS)
- 21H04711 and 21H05030 MEXT | Japan Society for the Promotion of Science (JSPS)
- URPP Evolutoin in Action, Global Strategy and Partnerships Funding Scheme Universität Zürich (University of Zurich)
- URPP Evolutoini in Action Universität Zürich (University of Zurich)
- fellowship European Molecular Biology Organization (EMBO)
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Affiliation(s)
- Chow-Lih Yew
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057, Zurich, Switzerland
- Department of Plant and Microbial Biology, University of Zurich, 8008, Zurich, Switzerland
| | - Takashi Tsuchimatsu
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057, Zurich, Switzerland
- Department of Plant and Microbial Biology, University of Zurich, 8008, Zurich, Switzerland
- Department of Biological Sciences, University of Tokyo, Tokyo, 113-0033, Japan
| | - Rie Shimizu-Inatsugi
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057, Zurich, Switzerland
- Department of Plant and Microbial Biology, University of Zurich, 8008, Zurich, Switzerland
| | - Shinsuke Yasuda
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, 630-0192, Japan
| | - Masaomi Hatakeyama
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057, Zurich, Switzerland
- Department of Plant and Microbial Biology, University of Zurich, 8008, Zurich, Switzerland
- Functional Genomics Center Zurich, 8057, Zurich, Switzerland
| | - Hiroyuki Kakui
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057, Zurich, Switzerland
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, 244-0813, Japan
- Institute for Sustainable Agro-ecosystem Services, Graduate School of Agricultural and Life Sciences, University of Tokyo, Nishitokyo, 188-0002, Japan
- Graduate School of Agriculture, Kyoto University, Kyoto, 606-8502, Japan
| | - Takuma Ohta
- Graduate School of Bioresources, Mie University, Tsu, 514-0102, Japan
| | - Keita Suwabe
- Graduate School of Bioresources, Mie University, Tsu, 514-0102, Japan
| | - Masao Watanabe
- Graduate School of Life Sciences, Tohoku University, Sendai, 980-8577, Japan
| | - Seiji Takayama
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, 630-0192, Japan
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, 113-8657, Japan
| | - Kentaro K Shimizu
- Department of Evolutionary Biology and Environmental Studies, University of Zurich, 8057, Zurich, Switzerland.
- Department of Plant and Microbial Biology, University of Zurich, 8008, Zurich, Switzerland.
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, 244-0813, Japan.
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6
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Orantes-Bonilla M, Makhoul M, Lee H, Chawla HS, Vollrath P, Langstroff A, Sedlazeck FJ, Zou J, Snowdon RJ. Frequent spontaneous structural rearrangements promote rapid genome diversification in a Brassica napus F1 generation. FRONTIERS IN PLANT SCIENCE 2022; 13:1057953. [PMID: 36466276 PMCID: PMC9716091 DOI: 10.3389/fpls.2022.1057953] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 10/31/2022] [Indexed: 05/26/2023]
Abstract
In a cross between two homozygous Brassica napus plants of synthetic and natural origin, we demonstrate that novel structural genome variants from the synthetic parent cause immediate genome diversification among F1 offspring. Long read sequencing in twelve F1 sister plants revealed five large-scale structural rearrangements where both parents carried different homozygous alleles but the heterozygous F1 genomes were not identical heterozygotes as expected. Such spontaneous rearrangements were part of homoeologous exchanges or segmental deletions and were identified in different, individual F1 plants. The variants caused deletions, gene copy-number variations, diverging methylation patterns and other structural changes in large numbers of genes and may have been causal for unexpected phenotypic variation between individual F1 sister plants, for example strong divergence of plant height and leaf area. This example supports the hypothesis that spontaneous de novo structural rearrangements after de novo polyploidization can rapidly overcome intense allopolyploidization bottlenecks to re-expand crops genetic diversity for ecogeographical expansion and human selection. The findings imply that natural genome restructuring in allopolyploid plants from interspecific hybridization, a common approach in plant breeding, can have a considerably more drastic impact on genetic diversity in agricultural ecosystems than extremely precise, biotechnological genome modifications.
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Affiliation(s)
- Mauricio Orantes-Bonilla
- Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany
| | - Manar Makhoul
- Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany
| | - HueyTyng Lee
- Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany
| | - Harmeet Singh Chawla
- Department of Plant Sciences, Crop Development Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | - Paul Vollrath
- Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany
| | - Anna Langstroff
- Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany
| | - Fritz J. Sedlazeck
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, United States
| | - Jun Zou
- National Key Laboratory of Crop Genetic Improvement, College of Plant Science & Technology, Huazhong Agricultural University, Wuhan, China
| | - Rod J. Snowdon
- Department of Plant Breeding, IFZ Research Centre for Biosystems, Land Use and Nutrition, Justus Liebig University, Giessen, Germany
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7
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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.
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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
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8
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Hoffmann G, Mahboubi A, Bente H, Garcia D, Hanson J, Hafrén A. Arabidopsis RNA processing body components LSM1 and DCP5 aid in the evasion of translational repression during Cauliflower mosaic virus infection. THE PLANT CELL 2022; 34:3128-3147. [PMID: 35511183 PMCID: PMC9338796 DOI: 10.1093/plcell/koac132] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 04/24/2022] [Indexed: 06/14/2023]
Abstract
Viral infections impose extraordinary RNA stress, triggering cellular RNA surveillance pathways such as RNA decapping, nonsense-mediated decay, and RNA silencing. Viruses need to maneuver among these pathways to establish infection and succeed in producing high amounts of viral proteins. Processing bodies (PBs) are integral to RNA triage in eukaryotic cells, with several distinct RNA quality control pathways converging for selective RNA regulation. In this study, we investigated the role of Arabidopsis thaliana PBs during Cauliflower mosaic virus (CaMV) infection. We found that several PB components are co-opted into viral factories that support virus multiplication. This pro-viral role was not associated with RNA decay pathways but instead, we established that PB components are helpers in viral RNA translation. While CaMV is normally resilient to RNA silencing, dysfunctions in PB components expose the virus to this pathway, which is similar to previous observations for transgenes. Transgenes, however, undergo RNA quality control-dependent RNA degradation and transcriptional silencing, whereas CaMV RNA remains stable but becomes translationally repressed through decreased ribosome association, revealing a unique dependence among PBs, RNA silencing, and translational repression. Together, our study shows that PB components are co-opted by the virus to maintain efficient translation, a mechanism not associated with canonical PB functions.
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Affiliation(s)
- Gesa Hoffmann
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala 75007, Sweden
- Linnean Center for Plant Biology, Uppsala 75007, Sweden
| | - Amir Mahboubi
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
| | - Heinrich Bente
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala 75007, Sweden
- Linnean Center for Plant Biology, Uppsala 75007, Sweden
| | - Damien Garcia
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Johannes Hanson
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
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9
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Abstract
Increasing evidence indicates that non-DNA sequence-based epigenetic information can be inherited across several generations in organisms ranging from yeast to plants to humans. This raises the possibility of heritable 'epimutations' contributing to heritable phenotypic variation and thus to evolution. Recent work has shed light on both the signals that underpin these epimutations, including DNA methylation, histone modifications and non-coding RNAs, and the mechanisms by which they are transmitted across generations at the molecular level. These mechanisms can vary greatly among species and have a more limited effect in mammals than in plants and other animal species. Nevertheless, common principles are emerging, with transmission occurring either via direct replicative mechanisms or indirect reconstruction of the signal in subsequent generations. As these processes become clearer we continue to improve our understanding of the distinctive features and relative contribution of DNA sequence and epigenetic variation to heritable differences in phenotype.
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10
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Pereira R, Leitão JM. A Non-Rogue Mutant Line Induced by ENU Mutagenesis in Paramutated Rogue Peas ( Pisum sativum L.) Is Still Sensitive to the Rogue Paramutation. Genes (Basel) 2021; 12:1680. [PMID: 34828288 PMCID: PMC8623080 DOI: 10.3390/genes12111680] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 10/18/2021] [Accepted: 10/22/2021] [Indexed: 11/16/2022] Open
Abstract
The spontaneously emerging rogue phenotype in peas (Pisum sativum L.), characterized by narrow and pointed leaf stipula and leaflets, was the first identified case of the epigenetic phenomenon paramutation. The crosses of homozygous or heterozygous (e.g., F1) rogue plants with non-rogue (wild type) plants, produce exclusively rogue plants in the first and all subsequent generations. The fact that the wild phenotype disappears forever, is in clear contradiction with the Mendelian rules of inheritance, a situation that impedes the positional cloning of genes involved in this epigenetic phenomenon. One way of overcoming this obstacle is the identification of plant genotypes harboring naturally occurring or artificially induced neutral alleles, non-sensitive to paramutation. So far, such alleles have never been described for the pea rogue paramutation. Here, we report the induction via 1-ethyl-1-nitrosourea (ENU) mutagenesis of a non-rogue revertant mutant in the rogue cv. Progreta, and the completely unusual fixation of the induced non-rogue phenotype through several generations. The reversion of the methylation status of two previously identified differentially methylated genomic sequences in the induced non-rogue mutant, confirms that the rogue paramutation is accompanied by alterations in DNA methylation. Nevertheless, unexpectedly, the induced non-rogue mutant showed to be still sensitive to paramutation.
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Affiliation(s)
- Ricardo Pereira
- Laboratory of Genomics and Genetic Improvement, MED, FCT, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal;
- Corte Velada Investimentos, Monte Ruivo, PB 552X, 8600-237 Odiáxere, Portugal
| | - José M. Leitão
- Laboratory of Genomics and Genetic Improvement, MED, FCT, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal;
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