1
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Zhang H, Zhu JK. Epigenetic gene regulation in plants and its potential applications in crop improvement. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00769-1. [PMID: 39192154 DOI: 10.1038/s41580-024-00769-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2024] [Indexed: 08/29/2024]
Abstract
DNA methylation, also known as 5-methylcytosine, is an epigenetic modification that has crucial functions in plant growth, development and adaptation. The cellular DNA methylation level is tightly regulated by the combined action of DNA methyltransferases and demethylases. Protein complexes involved in the targeting and interpretation of DNA methylation have been identified, revealing intriguing roles of methyl-DNA binding proteins and molecular chaperones. Structural studies and in vitro reconstituted enzymatic systems have provided mechanistic insights into RNA-directed DNA methylation, the main pathway catalysing de novo methylation in plants. A better understanding of the regulatory mechanisms will enable locus-specific manipulation of the DNA methylation status. CRISPR-dCas9-based epigenome editing tools are being developed for this goal. Given that DNA methylation patterns can be stably transmitted through meiosis, and that large phenotypic variations can be contributed by epimutations, epigenome editing holds great promise in crop breeding by creating additional phenotypic variability on the same genetic material.
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Affiliation(s)
- Heng Zhang
- Department of Genetics and Developmental Science, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
| | - Jian-Kang Zhu
- Institute of Advanced Biotechnology and School of Medicine, Southern University of Science and Technology, Shenzhen, China.
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2
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Kulikova DA, Bespalova AV, Zelentsova ES, Evgen'ev MB, Funikov SY. Epigenetic Phenomenon of Paramutation in Plants and Animals. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:1429-1450. [PMID: 39245454 DOI: 10.1134/s0006297924080054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 06/17/2024] [Accepted: 06/27/2024] [Indexed: 09/10/2024]
Abstract
The phenomenon of paramutation describes the interaction between two alleles, in which one allele initiates inherited epigenetic conversion of another allele without affecting the DNA sequence. Epigenetic transformations due to paramutation are accompanied by the change in DNA and/or histone methylation patterns, affecting gene expression. Studies of paramutation in plants and animals have identified small non-coding RNAs as the main effector molecules required for the initiation of epigenetic changes in gene loci. Due to the fact that small non-coding RNAs can be transmitted across generations, the paramutation effect can be inherited and maintained in a population. In this review, we will systematically analyze examples of paramutation in different living systems described so far, highlighting common and different molecular and genetic aspects of paramutation between organisms, and considering the role of this phenomenon in evolution.
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Affiliation(s)
- Dina A Kulikova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
- Koltzov Institute of Developmental Biology, Russian Academy of Sciences, Moscow, 119334, Russia
| | - Alina V Bespalova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Elena S Zelentsova
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Mikhail B Evgen'ev
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia
| | - Sergei Yu Funikov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow, 119991, Russia.
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3
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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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4
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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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5
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Kumar S, Singh A, Bist CMS, Sharma M. Advancements in genetic techniques and functional genomics for enhancing crop traits and agricultural sustainability. Brief Funct Genomics 2024:elae017. [PMID: 38679487 DOI: 10.1093/bfgp/elae017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/03/2024] [Accepted: 04/16/2024] [Indexed: 05/01/2024] Open
Abstract
Genetic variability is essential for the development of new crop varieties with economically beneficial traits. The traits can be inherited from wild relatives or induced through mutagenesis. Novel genetic elements can then be identified and new gene functions can be predicted. In this study, forward and reverse genetics approaches were described, in addition to their applications in modern crop improvement programs and functional genomics. By using heritable phenotypes and linked genetic markers, forward genetics searches for genes by using traditional genetic mapping and allele frequency estimation. Despite recent advances in sequencing technology, omics and computation, genetic redundancy remains a major challenge in forward genetics. By analyzing close-related genes, we will be able to dissect their functional redundancy and predict possible traits and gene activity patterns. In addition to these predictions, sophisticated reverse gene editing tools can be used to verify them, including TILLING, targeted insertional mutagenesis, gene silencing, gene targeting and genome editing. By using gene knock-down, knock-up and knock-out strategies, these tools are able to detect genetic changes in cells. In addition, epigenome analysis and editing enable the development of novel traits in existing crop cultivars without affecting their genetic makeup by increasing epiallelic variants. Our understanding of gene functions and molecular dynamics of various biological phenomena has been revised by all of these findings. The study also identifies novel genetic targets in crop species to improve yields and stress tolerances through conventional and non-conventional methods. In this article, genetic techniques and functional genomics are specifically discussed and assessed for their potential in crop improvement.
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Affiliation(s)
- Surender Kumar
- Department of Biotechnology, College of Horticulture, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan-173230, Himachal Pradesh, India
| | - Anupama Singh
- Department of Biotechnology, College of Horticulture, Dr. Y. S. Parmar University of Horticulture and Forestry, Nauni, Solan-173230, Himachal Pradesh, India
| | - Chander Mohan Singh Bist
- Indian Council of Agricultural Research (ICAR)-Central Potato Research Institute, Shimla-171001, Himachal Pradesh, India
| | - Munish Sharma
- Department of Plant Sciences, Central University of Himachal Pradesh, Dharamshala-176215, Himachal Pradesh, India
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6
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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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7
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Sahu A, Verma R, Gupta U, Kashyap S, Sanyal I. An Overview of Targeted Genome Editing Strategies for Reducing the Biosynthesis of Phytic Acid: an Anti-nutrient in Crop Plants. Mol Biotechnol 2024; 66:11-25. [PMID: 37061991 DOI: 10.1007/s12033-023-00722-1] [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] [Received: 01/26/2023] [Accepted: 03/11/2023] [Indexed: 04/17/2023]
Abstract
Anti-nutrients are substances either found naturally or are of synthetic origin, which leads to the inactivation of nutrients and limits their utilization in metabolic processes. Phytic acid is classified as an anti-nutrient, as it has a strong binding affinity with most minerals like Fe, Zn, Mg, Ca, Mn, and Cd and impairs their proper metabolism. Removing anti-nutrients from cereal grains may enable the bioavailability of both macro- and micronutrients which is the desired goal of genetic engineering tools for the betterment of agronomic traits. Several strategies have been adopted to minimize phytic acid content in plants. Pursuing the molecular strategies, there are several studies, which result in the decrement of the total phytic acid content in grains of major as well as minor crops. Biosynthesis of phytic acid mainly takes place in the seed comprising lipid-dependent and lipid-independent pathways, involving various enzymes. Furthermore, some studies show that interruption of these enzymes may involve the pleiotropic effect. However, using modern biotechnological approaches, undesirable agronomic traits can be removed. This review presents an overview of different genes encoding the various enzymes involved in the biosynthetic pathway of phytic acid which is being targeted for its reduction. It also, highlights and enumerates the variety of potential applications of genome editing tools such as TALEN, ZFN, and CRISPR/Cas9 to knock out the desired genes, and RNAi for their silencing.
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Affiliation(s)
- Anshu Sahu
- Plant Transgenic Laboratory, Molecular Biology and Biotechnology Division, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, U.P, 226001, India
| | - Rita Verma
- Plant Transgenic Laboratory, Molecular Biology and Biotechnology Division, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, U.P, 226001, India
| | - Uma Gupta
- Plant Transgenic Laboratory, Molecular Biology and Biotechnology Division, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, U.P, 226001, India
| | - Shashi Kashyap
- Plant Transgenic Laboratory, Molecular Biology and Biotechnology Division, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, U.P, 226001, India
| | - Indraneel Sanyal
- Plant Transgenic Laboratory, Molecular Biology and Biotechnology Division, CSIR-National Botanical Research Institute, Rana Pratap Marg, Lucknow, U.P, 226001, India.
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Colombo F, Pagano A, Sangiorgio S, Macovei A, Balestrazzi A, Araniti F, Pilu R. Study of Seed Ageing in lpa1-1 Maize Mutant and Two Possible Approaches to Restore Seed Germination. Int J Mol Sci 2023; 24:ijms24010732. [PMID: 36614175 PMCID: PMC9820859 DOI: 10.3390/ijms24010732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 12/16/2022] [Accepted: 12/16/2022] [Indexed: 01/03/2023] Open
Abstract
Phytic acid (PA) is a strong anti-nutritional factor with a key antioxidant role in countering reactive oxygen species. Despite the potential benefits of low phytic acid (lpa) mutants, the reduction of PA causes pleiotropic effects, e.g., reduced seed germination and viability loss related to seed ageing. The current study evaluated a historical series of naturally aged seeds and showed that lpa1-1 seeds aged faster as compared to wildtype. To mimic natural ageing, the present study set up accelerated ageing treatments at different temperatures. It was found that incubating the seeds at 57 °C for 24 h, the wildtype germinated at 82.4% and lpa1-1 at 40%. The current study also hypothesized two possible solutions to overcome these problems: (1) Classical breeding was used to constitute synthetic populations carrying the lpa1-1 mutation, with genes pushing anthocyanin accumulation in the embryo (R-navajo allele). The outcome showed that the presence of R-navajo in the lpa1-1 genotype was not able to improve the germinability (-20%), but this approach could be useful to improve the germinability in non-mutant genotypes (+17%). (2) In addition, hydropriming was tested on lpa1-1 and wildtype seeds, and germination was improved by 20% in lpa1-1, suggesting a positive role of seed priming in restoring germination. Moreover, the data highlighted metabolic differences in the metabolome before and after hydropriming treatment, suggesting that the differences in germination could also be mediated by differences in the metabolic composition induced by the mutation.
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Affiliation(s)
- Federico Colombo
- Department of Agricultural and Environmental Sciences—Production, Landscape, Agroenergy, Università degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy
| | - Andrea Pagano
- Department of Biology and Biotechnology ‘L. Spallanzani’, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Stefano Sangiorgio
- Department of Agricultural and Environmental Sciences—Production, Landscape, Agroenergy, Università degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy
| | - Anca Macovei
- Department of Biology and Biotechnology ‘L. Spallanzani’, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Alma Balestrazzi
- Department of Biology and Biotechnology ‘L. Spallanzani’, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Fabrizio Araniti
- Department of Agricultural and Environmental Sciences—Production, Landscape, Agroenergy, Università degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy
| | - Roberto Pilu
- Department of Agricultural and Environmental Sciences—Production, Landscape, Agroenergy, Università degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy
- Correspondence:
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Varotto S, Krugman T, Aiese Cigliano R, Kashkush K, Kondić-Špika A, Aravanopoulos FA, Pradillo M, Consiglio F, Aversano R, Pecinka A, Miladinović D. Exploitation of epigenetic variation of crop wild relatives for crop improvement and agrobiodiversity preservation. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2022; 135:3987-4003. [PMID: 35678824 PMCID: PMC9729329 DOI: 10.1007/s00122-022-04122-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/04/2022] [Indexed: 05/05/2023]
Abstract
Crop wild relatives (CWRs) are recognized as the best potential source of traits for crop improvement. However, successful crop improvement using CWR relies on identifying variation in genes controlling desired traits in plant germplasms and subsequently incorporating them into cultivars. Epigenetic diversity may provide an additional layer of variation within CWR and can contribute novel epialleles for key traits for crop improvement. There is emerging evidence that epigenetic variants of functional and/or agronomic importance exist in CWR gene pools. This provides a rationale for the conservation of epigenotypes of interest, thus contributing to agrobiodiversity preservation through conservation and (epi)genetic monitoring. Concepts and techniques of classical and modern breeding should consider integrating recent progress in epigenetics, initially by identifying their association with phenotypic variations and then by assessing their heritability and stability in subsequent generations. New tools available for epigenomic analysis offer the opportunity to capture epigenetic variation and integrate it into advanced (epi)breeding programmes. Advances in -omics have provided new insights into the sources and inheritance of epigenetic variation and enabled the efficient introduction of epi-traits from CWR into crops using epigenetic molecular markers, such as epiQTLs.
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Affiliation(s)
- Serena Varotto
- Department of Agronomy Animal Food Natural Resources and Environment, University of Padova, Viale dell'Università, 16 35020, Legnaro, Italy.
| | - Tamar Krugman
- Institute of Evolution, University of Haifa, Abba Khoushy Ave 199, 3498838, Haifa, Israel
| | | | - Khalil Kashkush
- Department of Life Sciences, Ben-Gurion University, Beersheba, 84105, Israel
| | - Ankica Kondić-Špika
- Institute of Field and Vegetable Crops, Maksima Gorkog 30, 21000, Novi Sad, Serbia
| | - Fillipos A Aravanopoulos
- Faculty of Agriculture, Forest Science & Natural Environment, Aristotle University of Thessaloniki, Thessaloniki, GR54006, Greece
| | - Monica Pradillo
- Department of Genetics, Physiology and Microbiology, Faculty of Biology, Complutense University of Madrid, 28040, Madrid, Spain
| | - Federica Consiglio
- Institute of Biosciences and Bioresources, National Research Council (CNR), Via Università 133, 80055, Portici, Italy
| | - Riccardo Aversano
- Department of Agricultural Sciences, University of Naples Federico II, Via Università 100, 80055, Portici, Italy
| | - Ales Pecinka
- Institute of Experimental Botany, Centre of the Region Haná for Biotechnological and Agricultural Research, Czech Acad Sci, Šlechtitelů 31, 779 00, Olomouc, Czech Republic
| | - Dragana Miladinović
- Institute of Field and Vegetable Crops, Maksima Gorkog 30, 21000, Novi Sad, Serbia
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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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11
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Ashraf MF, Hou D, Hussain Q, Imran M, Pei J, Ali M, Shehzad A, Anwar M, Noman A, Waseem M, Lin X. Entailing the Next-Generation Sequencing and Metabolome for Sustainable Agriculture by Improving Plant Tolerance. Int J Mol Sci 2022; 23:651. [PMID: 35054836 PMCID: PMC8775971 DOI: 10.3390/ijms23020651] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2021] [Revised: 12/23/2021] [Accepted: 12/29/2021] [Indexed: 02/07/2023] Open
Abstract
Crop production is a serious challenge to provide food for the 10 billion individuals forecasted to live across the globe in 2050. The scientists' emphasize establishing an equilibrium among diversity and quality of crops by enhancing yield to fulfill the increasing demand for food supply sustainably. The exploitation of genetic resources using genomics and metabolomics strategies can help generate resilient plants against stressors in the future. The innovation of the next-generation sequencing (NGS) strategies laid the foundation to unveil various plants' genetic potential and help us to understand the domestication process to unmask the genetic potential among wild-type plants to utilize for crop improvement. Nowadays, NGS is generating massive genomic resources using wild-type and domesticated plants grown under normal and harsh environments to explore the stress regulatory factors and determine the key metabolites. Improved food nutritional value is also the key to eradicating malnutrition problems around the globe, which could be attained by employing the knowledge gained through NGS and metabolomics to achieve suitability in crop yield. Advanced technologies can further enhance our understanding in defining the strategy to obtain a specific phenotype of a crop. Integration among bioinformatic tools and molecular techniques, such as marker-assisted, QTLs mapping, creation of reference genome, de novo genome assembly, pan- and/or super-pan-genomes, etc., will boost breeding programs. The current article provides sequential progress in NGS technologies, a broad application of NGS, enhancement of genetic manipulation resources, and understanding the crop response to stress by producing plant metabolites. The NGS and metabolomics utilization in generating stress-tolerant plants/crops without deteriorating a natural ecosystem is considered a sustainable way to improve agriculture production. This highlighted knowledge also provides useful research that explores the suitable resources for agriculture sustainability.
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Affiliation(s)
- Muhammad Furqan Ashraf
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, 666 Wusu Street, Lin’An, Hangzhou 311300, China; (M.F.A.); (D.H.); (Q.H.); (J.P.)
| | - Dan Hou
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, 666 Wusu Street, Lin’An, Hangzhou 311300, China; (M.F.A.); (D.H.); (Q.H.); (J.P.)
| | - Quaid Hussain
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, 666 Wusu Street, Lin’An, Hangzhou 311300, China; (M.F.A.); (D.H.); (Q.H.); (J.P.)
| | - Muhammad Imran
- Colleges of Agriculture and Horticulture, South China Agricultural University, Guangzhou 510642, China; (M.I.); (M.W.)
| | - Jialong Pei
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, 666 Wusu Street, Lin’An, Hangzhou 311300, China; (M.F.A.); (D.H.); (Q.H.); (J.P.)
| | - Mohsin Ali
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China;
| | - Aamar Shehzad
- Maize Research Station, AARI, Faisalabad 38000, Pakistan;
| | - Muhammad Anwar
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China;
| | - Ali Noman
- Department of Botany, Government College University, Faisalabad 38000, Pakistan;
| | - Muhammad Waseem
- Colleges of Agriculture and Horticulture, South China Agricultural University, Guangzhou 510642, China; (M.I.); (M.W.)
| | - Xinchun Lin
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, 666 Wusu Street, Lin’An, Hangzhou 311300, China; (M.F.A.); (D.H.); (Q.H.); (J.P.)
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12
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Gupta C, Salgotra RK. Epigenetics and its role in effecting agronomical traits. FRONTIERS IN PLANT SCIENCE 2022; 13:925688. [PMID: 36046583 PMCID: PMC9421166 DOI: 10.3389/fpls.2022.925688] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 07/11/2022] [Indexed: 05/16/2023]
Abstract
Climate-resilient crops with improved adaptation to the changing climate are urgently needed to feed the growing population. Hence, developing high-yielding crop varieties with better agronomic traits is one of the most critical issues in agricultural research. These are vital to enhancing yield as well as resistance to harsh conditions, both of which help farmers over time. The majority of agronomic traits are quantitative and are subject to intricate genetic control, thereby obstructing crop improvement. Plant epibreeding is the utilisation of epigenetic variation for crop development, and has a wide range of applications in the field of crop improvement. Epigenetics refers to changes in gene expression that are heritable and induced by methylation of DNA, post-translational modifications of histones or RNA interference rather than an alteration in the underlying sequence of DNA. The epigenetic modifications influence gene expression by changing the state of chromatin, which underpins plant growth and dictates phenotypic responsiveness for extrinsic and intrinsic inputs. Epigenetic modifications, in addition to DNA sequence variation, improve breeding by giving useful markers. Also, it takes epigenome diversity into account to predict plant performance and increase crop production. In this review, emphasis has been given for summarising the role of epigenetic changes in epibreeding for crop improvement.
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13
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Schulze WX, Altenbuchinger M, He M, Kränzlein M, Zörb C. Proteome profiling of repeated drought stress reveals genotype-specific responses and memory effects in maize. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2021; 159:67-79. [PMID: 33341081 DOI: 10.1016/j.plaphy.2020.12.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 12/08/2020] [Indexed: 06/12/2023]
Abstract
Drought has become a major stress for agricultural productivity in temperate regions, such as central Europe. Thus, information on how crop plants respond to drought is important to develop tolerant hybrids and to ensure yield stability. Posttranscriptional regulation through changed protein abundances is an important mechanism of short-term response to stress events that has not yet been widely exploited in breeding strategies. Here, we investigated the response to repeated drought exposure of a tolerant and a sensitive maize hybrid in order to understand general protein abundance changes induced by singular drought or repeated drought events. In general, drought affected protein abundance of multiple pathways in the plant. We identified starch metabolism, aquaporin abundance, PSII proteins and histones as strongly associated with typical drought-induced phenotypes such as increased membrane leakage, osmolality or effects on stomatal conductance and assimilation rate. In addition, we found a strong effect of drought on nutrient assimilation, especially the sulfur metabolism. In general, pre-experience of mild drought before exposure to a more severe drought resulted in visible adaptations resulting in dampened phenotypes as well as lower magnitude of protein abundance changes.
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Affiliation(s)
- Waltraud X Schulze
- Department of Plant Systems Biology, University of Hohenheim, 70593, Stuttgart, Germany.
| | - Michael Altenbuchinger
- Research Group Computational Biology, University of Hohenheim, 70593, Stuttgart, Germany
| | - Mingjie He
- Department of Plant Systems Biology, University of Hohenheim, 70593, Stuttgart, Germany
| | - Markus Kränzlein
- Institute of Crop Sciences, University of Hohenheim, 70593, Stuttgart, Germany
| | - Christian Zörb
- Institute of Crop Sciences, University of Hohenheim, 70593, Stuttgart, Germany
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14
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Quantitative Epigenetics: A New Avenue for Crop Improvement. EPIGENOMES 2020; 4:epigenomes4040025. [PMID: 34968304 PMCID: PMC8594725 DOI: 10.3390/epigenomes4040025] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 10/24/2020] [Accepted: 11/04/2020] [Indexed: 12/30/2022] Open
Abstract
Plant breeding conventionally depends on genetic variability available in a species to improve a particular trait in the crop. However, epigenetic diversity may provide an additional tier of variation. The recent advent of epigenome technologies has elucidated the role of epigenetic variation in shaping phenotype. Furthermore, the development of epigenetic recombinant inbred lines (epi-RILs) in model species such as Arabidopsis has enabled accurate genetic analysis of epigenetic variation. Subsequently, mapping of epigenetic quantitative trait loci (epiQTL) allowed association between epialleles and phenotypic traits. Likewise, epigenome-wide association study (EWAS) and epi-genotyping by sequencing (epi-GBS) have revolutionized the field of epigenetics research in plants. Thus, quantitative epigenetics provides ample opportunities to dissect the role of epigenetic variation in trait regulation, which can be eventually utilized in crop improvement programs. Moreover, locus-specific manipulation of DNA methylation by epigenome-editing tools such as clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) can potentially facilitate epigenetic based molecular breeding of important crop plants.
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15
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Cominelli E, Pilu R, Sparvoli F. Phytic Acid and Transporters: What Can We Learn from low phytic acid Mutants. PLANTS 2020; 9:plants9010069. [PMID: 31948109 PMCID: PMC7020491 DOI: 10.3390/plants9010069] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 12/23/2019] [Accepted: 01/01/2020] [Indexed: 01/22/2023]
Abstract
Phytic acid has two main roles in plant tissues: Storage of phosphorus and regulation of different cellular processes. From a nutritional point of view, it is considered an antinutritional compound because, being a cation chelator, its presence reduces mineral bioavailability from the diet. In recent decades, the development of low phytic acid (lpa) mutants has been an important goal for nutritional seed quality improvement, mainly in cereals and legumes. Different lpa mutations affect phytic acid biosynthetic genes. However, other lpa mutations isolated so far, affect genes coding for three classes of transporters: A specific group of ABCC type vacuolar transporters, putative sulfate transporters, and phosphate transporters. In the present review, we summarize advances in the characterization of these transporters in cereals and legumes. Particularly, we describe genes, proteins, and mutants for these different transporters, and we report data of in silico analysis aimed at identifying the putative orthologs in some other cereal and legume species. Finally, we comment on the advantage of using such types of mutants for crop biofortification and on their possible utility to unravel links between phosphorus and sulfur metabolism (phosphate and sulfate homeostasis crosstalk).
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Affiliation(s)
- Eleonora Cominelli
- Institute of Agricultural Biology and Biotechnology, Consiglio Nazionale delle Ricerche, Via E. Bassini 15, 20133 Milan, Italy;
- Correspondence: ; Tel.: +39-022-369-9421
| | - Roberto Pilu
- Department of Agricultural and Environmental Sciences—Production Landscape, Agroenergy Università degli Studi di Milano, Via G. Celoria 2, 20133 Milan, Italy;
| | - Francesca Sparvoli
- Institute of Agricultural Biology and Biotechnology, Consiglio Nazionale delle Ricerche, Via E. Bassini 15, 20133 Milan, Italy;
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16
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Colombo F, Paolo D, Cominelli E, Sparvoli F, Nielsen E, Pilu R. MRP Transporters and Low Phytic Acid Mutants in Major Crops: Main Pleiotropic Effects and Future Perspectives. FRONTIERS IN PLANT SCIENCE 2020; 11:1301. [PMID: 32973854 PMCID: PMC7481554 DOI: 10.3389/fpls.2020.01301] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2020] [Accepted: 08/11/2020] [Indexed: 05/15/2023]
Abstract
Phytic acid (PA) represents the major storage form of seed phosphate (P). During seed maturation, it accumulates as phytate salts chelating various mineral cations, therefore reducing their bioavailability. During germination, phytase dephosphorylates PA releasing both P and cations which in turn can be used for the nutrition of the growing seedling. Animals do not possess phytase, thus monogastric animals assimilate only 10% of the phytate ingested with feed, whilst 90% is excreted and may contribute to cause P pollution of the environment. To overcome this double problem, nutritional and environmental, in the last four decades, many low phytic acid (lpa) mutants (most of which affect the PA-MRP transporters) have been isolated and characterized in all major crops, showing that the lpa trait can increase the nutritional quality of foods and feeds and improve P management in agriculture. Nevertheless, these mutations are frequently accompanied by negative pleiotropic effects leading to agronomic defects which may affect either seed viability and germination or plant development or in some cases even increase the resistance to cooking, thus limiting the interest of breeders. Therefore, although some significant results have been reached, the isolation of lpa mutants improved for their nutritional quality and with a good field performance remains a goal so far not fully achieved for many crops. Here, we will summarize the main pleiotropic effects that have been reported to date in lpa mutants affected in PA-MRP transporters in five productive agronomic species, as well as addressing some of the possible challenges to overcome these hurdles and improve the breeding efforts for lpa mutants.
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Affiliation(s)
- Federico Colombo
- Department of Agricultural and Environmental Sciences—Production Landscape, Agroenergy, Università degli Studi di Milano, Milan, Italy
| | - Dario Paolo
- Institute of Agricultural Biology and Biotechnology, Consiglio Nazionale delle Ricerche (CNR), Milan, Italy
| | - Eleonora Cominelli
- Institute of Agricultural Biology and Biotechnology, Consiglio Nazionale delle Ricerche (CNR), Milan, Italy
| | - Francesca Sparvoli
- Institute of Agricultural Biology and Biotechnology, Consiglio Nazionale delle Ricerche (CNR), Milan, Italy
| | - Erik Nielsen
- Department of Biology and Biotechnology, Università degli Studi di Pavia, Pavia, Italy
| | - Roberto Pilu
- Department of Agricultural and Environmental Sciences—Production Landscape, Agroenergy, Università degli Studi di Milano, Milan, Italy
- *Correspondence: Roberto Pilu,
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17
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Borlini G, Rovera C, Landoni M, Cassani E, Pilu R. lpa1-5525: A New lpa1 Mutant Isolated in a Mutagenized Population by a Novel Non-Disrupting Screening Method. PLANTS 2019; 8:plants8070209. [PMID: 31284582 PMCID: PMC6681281 DOI: 10.3390/plants8070209] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 06/29/2019] [Accepted: 07/04/2019] [Indexed: 11/16/2022]
Abstract
Phytic acid, or myo-inositol 1,2,3,4,5,6-hexakisphosphate, is the main storage form of phosphorus in plants. It is localized in seeds, deposited as mixed salts of mineral cations in protein storage vacuoles; during germination, it is hydrolyzed by phytases to make available P together with all the other cations needed for seed germination. When seeds are used as food or feed, phytic acid and the bound cations are poorly bioavailable for human and monogastric livestock due to their lack of phytase activity. Therefore, reducing the amount of phytic acid is one strategy in breeding programs aimed to improve the nutritional properties of major crops. In this work, we present data on the isolation of a new maize (Zea mays L.) low phytic acid 1 (lpa1) mutant allele obtained by transposon tagging mutagenesis with the Ac element. We describe the generation of the mutagenized population and the screening to isolate new lpa1 mutants. In particular, we developed a fast, cheap and non-disrupting screening method based on the different density of lpa1 seed compared to the wild type. This assay allowed the isolation of the lpa1-5525 mutant characterized by a new mutation in the lpa1 locus associated with a lower amount of phytic phosphorus in the seeds in comparison with the wild type.
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Affiliation(s)
- Giulia Borlini
- Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy-Università degli Studi di Milano, Via Celoria 2, 20133 Milan, Italy
| | - Cesare Rovera
- Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy-Università degli Studi di Milano, Via Celoria 2, 20133 Milan, Italy
| | - Michela Landoni
- Department of Biosciences-Università degli Studi di Milano, Via Celoria 26, 20133 Milan, Italy
| | - Elena Cassani
- Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy-Università degli Studi di Milano, Via Celoria 2, 20133 Milan, Italy
| | - Roberto Pilu
- Department of Agricultural and Environmental Sciences-Production, Landscape, Agroenergy-Università degli Studi di Milano, Via Celoria 2, 20133 Milan, Italy.
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18
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Kawakatsu T, Ecker JR. Diversity and dynamics of DNA methylation: epigenomic resources and tools for crop breeding. BREEDING SCIENCE 2019; 69:191-204. [PMID: 31481828 PMCID: PMC6711733 DOI: 10.1270/jsbbs.19005] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 03/18/2019] [Indexed: 05/17/2023]
Abstract
DNA methylation is an epigenetic modification that can affect gene expression and transposable element (TE) activities. Because cytosine DNA methylation patterns are inherited through both mitotic and meiotic cell divisions, differences in these patterns can contribute to phenotypic variability. Advances in high-throughput sequencing technologies have enabled the generation of abundant DNA sequence data. Integrated analyses of genome-wide gene expression patterns and DNA methylation patterns have revealed the underlying mechanisms and functions of DNA methylation. Moreover, associations between DNA methylation and agronomic traits have also been uncovered. The resulting information may be useful for future applications of natural epigenomic variation, for crop breeding. Additionally, artificial epigenome editing may be an attractive new plant breeding technique for generating novel varieties with improved agronomic traits.
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Affiliation(s)
- Taiji Kawakatsu
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization,
1-2 Owashi Tsukuba, Ibaraki 305-8634,
Japan
- Corresponding author (e-mail: )
| | - Joseph R. Ecker
- Howard Hughes Medical Institute,
10010 North Torrey Pines Road, La Jolla, CA 92037,
USA
- The Salk Institute for Biological Studies,
10010 North Torrey Pines Road, La Jolla, CA 92037,
USA
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19
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Wang PH, Wittmeyer KT, Lee TF, Meyers BC, Chopra S. Overlapping RdDM and non-RdDM mechanisms work together to maintain somatic repression of a paramutagenic epiallele of maize pericarp color1. PLoS One 2017; 12:e0187157. [PMID: 29112965 PMCID: PMC5675401 DOI: 10.1371/journal.pone.0187157] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 10/14/2017] [Indexed: 11/18/2022] Open
Abstract
Allelic variation at the Zea mays (maize) pericarp color1 (p1) gene has been attributed to epigenetic gene regulation. A p1 distal enhancer, 5.2 kb upstream of the transcriptional start site, has demonstrated variation in DNA methylation in different p1 alleles/epialleles. In addition, DNA methylation of sequences within the 3’ end of intron 2 also plays a role in tissue-specific expression of p1 alleles. We show here a direct evidence for small RNAs’ involvement in regulating p1 that has not been demonstrated previously. The role of mediator of paramutation1 (mop1) was tested in the maintenance of somatic silencing at distinct p1 alleles: the non-paramutagenic P1-wr allele and paramutagenic P1-rr’ epiallele. The mop1-1 mutation gradually relieves the silenced phenotype after multiple generations of exposure; P1-wr;mop1-1 plants display a loss of 24-nt small RNAs and DNA methylation in the 3’ end of the intron 2, a region close to a Stowaway transposon. In addition, a MULE sequence within the proximal promoter of P1-wr shows depletion of 24nt siRNAs in mop1-1 plants. Release of silencing was not correlated with small RNAs at the distal enhancer region of the P1-wr allele. We found that the somatic silencing of the paramutagenic P1-rr’ is correlated with significantly reduced H3K9me2 in the distal enhancer of P1-rr’; mop1-1 plants, while symmetric DNA methylation is not significantly different. This study highlights that the epigenetic regulation of p1 alleles is controlled both via RdDM as well as non-RdDM mechanisms.
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Affiliation(s)
- Po-Hao Wang
- Department of Plant Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Kameron T. Wittmeyer
- Department of Plant Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Plant Biology Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Tzuu-fen Lee
- Department of Plant & Soil Sciences and Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, United States of America
| | - Blake C. Meyers
- Department of Plant & Soil Sciences and Delaware Biotechnology Institute, University of Delaware, Newark, Delaware, United States of America
| | - Surinder Chopra
- Department of Plant Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Plant Biology Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
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20
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Kumar R, Bohra A, Pandey AK, Pandey MK, Kumar A. Metabolomics for Plant Improvement: Status and Prospects. FRONTIERS IN PLANT SCIENCE 2017; 8:1302. [PMID: 28824660 PMCID: PMC5545584 DOI: 10.3389/fpls.2017.01302] [Citation(s) in RCA: 127] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2017] [Accepted: 07/11/2017] [Indexed: 05/12/2023]
Abstract
Post-genomics era has witnessed the development of cutting-edge technologies that have offered cost-efficient and high-throughput ways for molecular characterization of the function of a cell or organism. Large-scale metabolite profiling assays have allowed researchers to access the global data sets of metabolites and the corresponding metabolic pathways in an unprecedented way. Recent efforts in metabolomics have been directed to improve the quality along with a major focus on yield related traits. Importantly, an integration of metabolomics with other approaches such as quantitative genetics, transcriptomics and genetic modification has established its immense relevance to plant improvement. An effective combination of these modern approaches guides researchers to pinpoint the functional gene(s) and the characterization of massive metabolites, in order to prioritize the candidate genes for downstream analyses and ultimately, offering trait specific markers to improve commercially important traits. This in turn will improve the ability of a plant breeder by allowing him to make more informed decisions. Given this, the present review captures the significant leads gained in the past decade in the field of plant metabolomics accompanied by a brief discussion on the current contribution and the future scope of metabolomics to accelerate plant improvement.
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Affiliation(s)
- Rakesh Kumar
- Department of Plant Sciences, University of Hyderabad (UoH)Hyderabad, India
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)Hyderabad, India
| | - Abhishek Bohra
- Crop Improvement Division, Indian Institute of Pulses Research (IIPR)Kanpur, India
| | - Arun K. Pandey
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)Hyderabad, India
| | - Manish K. Pandey
- International Crops Research Institute for the Semi-Arid Tropics (ICRISAT)Hyderabad, India
| | - Anirudh Kumar
- Department of Botany, Indira Gandhi National Tribal University (IGNTU)Amarkantak, India
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21
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Epigenetic Control of Gene Expression in Maize. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2017; 328:25-48. [DOI: 10.1016/bs.ircmb.2016.08.002] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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22
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23
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Zhang S, Yang W, Zhao Q, Zhou X, Jiang L, Ma S, Liu X, Li Y, Zhang C, Fan Y, Chen R. Analysis of weighted co-regulatory networks in maize provides insights into new genes and regulatory mechanisms related to inositol phosphate metabolism. BMC Genomics 2016; 17:129. [PMID: 26911482 PMCID: PMC4765147 DOI: 10.1186/s12864-016-2476-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 02/16/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND D-myo-inositol phosphates (IPs) are a series of phosphate esters. Myo-inositol hexakisphosphate (phytic acid, IP6) is the most abundant IP and has negative effects on animal and human nutrition. IPs play important roles in plant development, stress responses, and signal transduction. However, the metabolic pathways and possible regulatory mechanisms of IPs in maize are unclear. In this study, the B73 (high in phytic acid) and Qi319 (low in phytic acid) lines were selected for RNA-Seq analysis from 427 inbred lines based on a screening of IP levels. By integrating the metabolite data with the RNA-Seq data at three different kernel developmental stages (12, 21 and 30 days after pollination), co-regulatory networks were constructed to explore IP metabolism and its interactions with other pathways. RESULTS Differentially expressed gene analyses showed that the expression of MIPS and ITPK was related to differences in IP metabolism in Qi319 and B73. Moreover, WRKY and ethylene-responsive transcription factors (TFs) were common among the differentially expressed TFs, and are likely to be involved in the regulation of IP metabolism. Six co-regulatory networks were constructed, and three were chosen for further analysis. Based on network analyses, we proposed that the GA pathway interacts with the IP pathway through the ubiquitination pathway, and that Ca(2+) signaling functions as a bridge between IPs and other pathways. IP pools were found to be transported by specific ATP-binding cassette (ABC) transporters. Finally, three candidate genes (Mf3, DH2 and CB5) were identified and validated using Arabidopsis lines with mutations in orthologous genes or RNA interference (RNAi)-transgenic maize lines. Some mutant or RNAi lines exhibited seeds with a low-phytic-acid phenotype, indicating perturbation of IP metabolism. Mf3 likely encodes an enzyme involved in IP synthesis, DH2 encodes a transporter responsible for IP transport across organs and CB5 encodes a transporter involved in IP co-transport into vesicles. CONCLUSIONS This study provides new insights into IP metabolism and regulation, and facilitates our development of a better understanding of the functions of IPs and how they interact with other pathways involved in plant development and stress responses. Three new genes were discovered and preliminarily validated, thereby increasing our knowledge of IP metabolism.
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Affiliation(s)
- Shaojun Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), 100081, Beijing, China.
| | - Wenzhu Yang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), 100081, Beijing, China.
| | - Qianqian Zhao
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), 100081, Beijing, China.
| | - Xiaojin Zhou
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), 100081, Beijing, China.
| | - Ling Jiang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), 100081, Beijing, China.
| | - Shuai Ma
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
| | - Xiaoqing Liu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), 100081, Beijing, China.
| | - Ye Li
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), 100081, Beijing, China.
| | - Chunyi Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), 100081, Beijing, China.
| | - Yunliu Fan
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), 100081, Beijing, China.
| | - Rumei Chen
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, 100081, Beijing, China.
- National Key Facility for Crop Gene Resources and Genetic Improvement (NFCRI), 100081, Beijing, China.
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24
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Springer NM, McGinnis KM. Paramutation in evolution, population genetics and breeding. Semin Cell Dev Biol 2015; 44:33-8. [PMID: 26325077 DOI: 10.1016/j.semcdb.2015.08.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 08/18/2015] [Indexed: 11/19/2022]
Abstract
Paramutation is a fascinating phenomenon in which directed allelic interactions result in heritable changes in the state of an allele. Paramutation has been carefully characterized at a handful of loci but the prevalence of paramutable/paramutagenic alleles is not well characterized within genomes or populations. In order to consider the role of paramutation in evolutionary processes and plant breeding, we focused on several questions. First, what causes certain alleles to become subject to paramutation? While paramutation clearly involves epigenetic regulation it is also true that only certain alleles defined by genetic sequences are able to participate in paramutation. Second, what is the prevalence of paramutation? There are only a handful of well-documented examples of paramutation. However, there is growing evidence that many loci may undergo changes in chromatin state or expression that are similar to changes observed as a result of paramutation. Third, how will paramutation events be inherited in natural or artificial populations? Many factors, including stability of epigenetic state, mating style and ploidy, may influence the prevalence of paramutation states within populations. Developing a clear understanding of the mechanisms and frequency of paramutation in crop plant genomes will facilitate new opportunities in genetic manipulation, and will also enhance plant breeding programs and our understanding of genome evolution.
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Affiliation(s)
- Nathan M Springer
- Microbial and Plant Genomics Institute, Department of Plant Biology, University of Minnesota, Saint Paul, MN 55108, USA.
| | - Karen M McGinnis
- Department of Biological Science, Florida State University, Tallahassee, FL 32306, USA
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25
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Gabriel JM, Hollick JB. Paramutation in maize and related behaviors in metazoans. Semin Cell Dev Biol 2015; 44:11-21. [PMID: 26318741 DOI: 10.1016/j.semcdb.2015.08.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2015] [Accepted: 08/18/2015] [Indexed: 12/31/2022]
Abstract
Paramutation refers to both the process and results of trans-homolog interactions causing heritable changes in both gene regulation and silencing abilities. Originally described in plants, paramutation-like behaviors have now been reported in model metazoans. Here we detail our current understanding of the paramutation mechanism as defined in Zea mays and compare this paradigm to these metazoan examples. Experimental results implicate functional roles of small RNAs in all these model organisms that highlight a diversity of mechanisms by which these molecules specify meiotically heritable regulatory information in the eukarya.
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Affiliation(s)
- Janelle M Gabriel
- Department of Molecular Genetics, Center for RNA Biology, The Ohio State University, Columbus, OH, USA
| | - Jay B Hollick
- Department of Molecular Genetics, Center for RNA Biology, The Ohio State University, Columbus, OH, USA.
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Pilu R. Paramutation phenomena in plants. Semin Cell Dev Biol 2015; 44:2-10. [DOI: 10.1016/j.semcdb.2015.08.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 08/26/2015] [Indexed: 02/05/2023]
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Nascent transcription affected by RNA polymerase IV in Zea mays. Genetics 2015; 199:1107-25. [PMID: 25653306 DOI: 10.1534/genetics.115.174714] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2014] [Accepted: 02/02/2015] [Indexed: 01/23/2023] Open
Abstract
All eukaryotes use three DNA-dependent RNA polymerases (RNAPs) to create cellular RNAs from DNA templates. Plants have additional RNAPs related to Pol II, but their evolutionary role(s) remain largely unknown. Zea mays (maize) RNA polymerase D1 (RPD1), the largest subunit of RNA polymerase IV (Pol IV), is required for normal plant development, paramutation, transcriptional repression of certain transposable elements (TEs), and transcriptional regulation of specific alleles. Here, we define the nascent transcriptomes of rpd1 mutant and wild-type (WT) seedlings using global run-on sequencing (GRO-seq) to identify the broader targets of RPD1-based regulation. Comparisons of WT and rpd1 mutant GRO-seq profiles indicate that Pol IV globally affects transcription at both transcriptional start sites and immediately downstream of polyadenylation addition sites. We found no evidence of divergent transcription from gene promoters as seen in mammalian GRO-seq profiles. Statistical comparisons identify genes and TEs whose transcription is affected by RPD1. Most examples of significant increases in genic antisense transcription appear to be initiated by 3'-proximal long terminal repeat retrotransposons. These results indicate that maize Pol IV specifies Pol II-based transcriptional regulation for specific regions of the maize genome including genes having developmental significance.
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Belele CL, Sidorenko L, Stam M, Bader R, Arteaga-Vazquez MA, Chandler VL. Specific tandem repeats are sufficient for paramutation-induced trans-generational silencing. PLoS Genet 2013; 9:e1003773. [PMID: 24146624 PMCID: PMC3798267 DOI: 10.1371/journal.pgen.1003773] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2012] [Accepted: 07/24/2013] [Indexed: 11/19/2022] Open
Abstract
Paramutation is a well-studied epigenetic phenomenon in which trans communication between two different alleles leads to meiotically heritable transcriptional silencing of one of the alleles. Paramutation at the b1 locus involves RNA-mediated transcriptional silencing and requires specific tandem repeats that generate siRNAs. This study addressed three important questions: 1) are the tandem repeats sufficient for paramutation, 2) do they need to be in an allelic position to mediate paramutation, and 3) is there an association between the ability to mediate paramutation and repeat DNA methylation levels? Paramutation was achieved using multiple transgenes containing the b1 tandem repeats, including events with tandem repeats of only one half of the repeat unit (413 bp), demonstrating that these sequences are sufficient for paramutation and an allelic position is not required for the repeats to communicate. Furthermore, the transgenic tandem repeats increased the expression of a reporter gene in maize, demonstrating the repeats contain transcriptional regulatory sequences. Transgene-mediated paramutation required the mediator of paramutation1 gene, which is necessary for endogenous paramutation, suggesting endogenous and transgene-mediated paramutation both require an RNA-mediated transcriptional silencing pathway. While all tested repeat transgenes produced small interfering RNAs (siRNAs), not all transgenes induced paramutation suggesting that, as with endogenous alleles, siRNA production is not sufficient for paramutation. The repeat transgene-induced silencing was less efficiently transmitted than silencing induced by the repeats of endogenous b1 alleles, which is always 100% efficient. The variability in the strength of the repeat transgene-induced silencing enabled testing whether the extent of DNA methylation within the repeats correlated with differences in efficiency of paramutation. Transgene-induced paramutation does not require extensive DNA methylation within the transgene. However, increased DNA methylation within the endogenous b1 repeats after transgene-induced paramutation was associated with stronger silencing of the endogenous allele. Paramutation is a fascinating process in which genes communicate to efficiently establish changes in their expression that are stably transmitted to future generations without any changes in DNA sequences. While paramutation was first described in the 1950s and extensively studied through the 1960s, its underlying mechanism remained mysterious for many years. Over the past ten years paramutation at the b1 locus in maize was shown to require transcribed, non-coding tandem repeats located 100 kb upstream of b1. These repeats generate small RNAs, and mutations in multiple genes mediating small RNA silencing at the transcriptional level prevent paramutation. While underlying mechanisms are shared, current models for RNA-mediated transcriptional silencing that are based on experiments with S. pombe and Arabidopsis do not explain many aspects of paramutation. In this manuscript we used a transgenic approach to demonstrate that the b1 non-coding tandem repeats are sufficient to send and respond to the paramutation signals and that this occurs even when the repeats are not at their normal chromosomal location.
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Affiliation(s)
- Christiane L. Belele
- Department of Plant Sciences, BIO5, University of Arizona, Tucson, Arizona, United States of America
| | - Lyudmila Sidorenko
- Department of Plant Sciences, BIO5, University of Arizona, Tucson, Arizona, United States of America
- * E-mail:
| | - Maike Stam
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Rechien Bader
- Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Mario A. Arteaga-Vazquez
- Department of Plant Sciences, BIO5, University of Arizona, Tucson, Arizona, United States of America
| | - Vicki L. Chandler
- Department of Plant Sciences, BIO5, University of Arizona, Tucson, Arizona, United States of America
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Goettel W, Messing J. Paramutagenicity of a p1 epiallele in maize. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2013; 126:159-77. [PMID: 22986680 DOI: 10.1007/s00122-012-1970-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Accepted: 08/16/2012] [Indexed: 05/09/2023]
Abstract
Complex silencing mechanisms in plants and other kingdoms target transposons, repeat sequences, invasive viral nucleic acids and transgenes, but also endogenous genes and genes involved in paramutation. Paramutation occurs in a heterozygote when a transcriptionally active allele heritably adopts the epigenetic state of a transcriptionally and/or post-transcriptionally repressed allele. P1-rr and its silenced epiallele P1-pr, which encode a Myb-like transcription factor mediating pigmentation in floral organs of Zea mays, differ in their cytosine methylation pattern and chromatin structure at a complex enhancer site. Here, we tested whether P1-pr is able to heritably silence its transcriptionally active P1-rr allele in a heterozygote and whether DNA methylation is associated with the establishment and maintenance of P1-rr silencing. We found that P1-pr participates in paramutation as the repressing allele and P1-rr as the sensitive allele. Silencing of P1-rr is highly variable compared to the inducing P1-pr resulting in a wide range of gene expression. Whereas cytosine methylation at P1-rr is negatively correlated with transcription and pigment levels after segregation of P1-pr, methylation lags behind the establishment of the repressed p1 gene expression. We propose a model in which P1-pr paramutation is triggered by changing epigenetic states of transposons immediately adjacent to a P1-rr enhancer sequence. Considering the vast amount of transposable elements in the maize genome close to regulatory elements of genes, numerous loci could undergo paramutation-induced allele silencing, which could also have a significant impact on breeding agronomically important traits.
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Affiliation(s)
- Wolfgang Goettel
- Waksman Institute of Microbiology, Rutgers University, 190 Frelinghuysen Road, Piscataway, NJ 08854, USA
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Hollick JB. Paramutation: a trans-homolog interaction affecting heritable gene regulation. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:536-543. [PMID: 23017240 DOI: 10.1016/j.pbi.2012.09.003] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Revised: 07/17/2012] [Accepted: 09/05/2012] [Indexed: 06/01/2023]
Abstract
Paramutation describes both the process and results of trans-sensing between chromosomes that causes specific heritable changes in gene regulation. RNA molecules are implicated in mediating similar events in maize, mouse, and Drosophila. Changes in both small RNA profiles and cytosine methylation patterns in Arabidopsis hybrids represent a potential molecular equivalent to the interactions responsible for paramutations. Despite a seemingly unifying feature of RNA-directed changes, both recent and historical works show that paramutations in maize require plant-specific proteins and lack expected hallmarks of a trans-effect mediated solely by RNAs. Recent examples of nearby transposons affecting RNA polymerase II functions lead to an opinion that paramutations represent an emergent property of the transcriptional dynamics ongoing in plant genomes between repetitious features and nearby genes.
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Affiliation(s)
- Jay B Hollick
- Department of Molecular Genetics, The Ohio State University, Columbus, OH 43210, USA.
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Sekhon RS, Wang PH, Sidorenko L, Chandler VL, Chopra S. Maize Unstable factor for orange1 is required for maintaining silencing associated with paramutation at the pericarp color1 and booster1 loci. PLoS Genet 2012; 8:e1002980. [PMID: 23055943 PMCID: PMC3464198 DOI: 10.1371/journal.pgen.1002980] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Accepted: 08/08/2012] [Indexed: 11/25/2022] Open
Abstract
To understand the molecular mechanisms underlying paramutation, we examined the role of Unstable factor for orange1 (Ufo1) in maintaining paramutation at the maize pericarp color1 (p1) and booster1 (b1) loci. Genetic tests revealed that the Ufo1-1 mutation disrupted silencing associated with paramutation at both p1 and b1. The level of up regulation achieved at b1 was lower than that at p1, suggesting differences in the role Ufo1-1 plays at these loci. We characterized the interaction of Ufo1-1 with two silenced p1 epialleles, P1-rr′ and P1-prTP, that were derived from a common P1-rr ancestor. Both alleles are phenotypically indistinguishable, but differ in their paramutagenic activity; P1-rr′ is paramutagenic to P1-rr, while P1-prTP is non-paramutagenic. Analysis of cytosine methylation revealed striking differences within an enhancer fragment that is required for paramutation; P1-rr′ exhibited increased methylation at symmetric (CG and CHG) and asymmetric (CHH) sites, while P1-prTP was methylated only at symmetric sites. Both silenced alleles had higher levels of dimethylation of lysine 9 on histone 3 (H3K9me2), an epigenetic mark of silent chromatin, in the enhancer region. Both epialleles were reactivated in the Ufo1-1 background; however, reactivation of P1-rr′ was associated with dramatic loss of symmetric and asymmetric cytosine methylation in the enhancer, while methylation of up-regulated P1-prTP was not affected. Interestingly, Ufo1-1–mediated reactivation of both alleles was accompanied with loss of H3K9me2 mark from the enhancer region. Therefore, while earlier studies have shown correlation between H3K9me2 and DNA methylation, our study shows that these two epigenetic marks are uncoupled in the Ufo1-1–reactivated p1 alleles. Furthermore, while CHH methylation at the enhancer region appears to be the major distinguishing mark between paramutagenic and non-paramutagenic p1 alleles, H3K9me2 mark appears to be important for maintaining epigenetic silencing. Natural allelic variability is crucial for genetic improvement. While the genetic mechanisms leading to such variation have been studied in depth, relatively less is known about the role of epigenetic mechanisms in generation of allelic diversity. Paramutation is a phenomenon in which one allele can silence another allele in trans and, once established, such epigenetic silencing is heritable. To further understand the molecular components of paramutation, we characterized two epialleles of the pericarp color1 (p1) gene of maize, which originated from a common progenitor; however, only one of these alleles is paramutagenic. Results show that, while both alleles have high levels of symmetric (CG and CHG) methylation in a distal enhancer element, only the paramutagenic allele has higher levels of asymmetric (CHH) methylation. Since CHH methylation is imposed and maintained through RNA–mediated mechanisms, these results indicate that paramutation at the p1 locus involves RNA–mediated silencing pathway. Further, both silent epialleles are reactivated in the presence of an unlinked dominant mutation Ufo1-1, and reactivation is accompanied by the loss of suppressive histone mark H3K9me2. Finally, we show that ufo1 is also required for epigenetic silencing at the booster1 locus and thus affects additional loci in maize that participate in paramutation.
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Affiliation(s)
- Rajandeep S. Sekhon
- Department of Plant Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Plant Biology Graduate Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Po-Hao Wang
- Department of Plant Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Lyudmila Sidorenko
- BIO5 Institute and Department of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Vicki L. Chandler
- BIO5 Institute and Department of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Surinder Chopra
- Department of Plant Science, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Plant Biology Graduate Program, Pennsylvania State University, University Park, Pennsylvania, United States of America
- * E-mail:
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de Vanssay A, Bougé AL, Boivin A, Hermant C, Teysset L, Delmarre V, Antoniewski C, Ronsseray S. Paramutation in Drosophila linked to emergence of a piRNA-producing locus. Nature 2012; 490:112-5. [PMID: 22922650 DOI: 10.1038/nature11416] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 07/16/2012] [Indexed: 11/10/2022]
Abstract
A paramutation is an epigenetic interaction between two alleles of a locus, through which one allele induces a heritable modification in the other allele without modifying the DNA sequence. The paramutated allele itself becomes paramutagenic, that is, capable of epigenetically converting a new paramutable allele. Here we describe a case of paramutation in animals showing long-term transmission over generations. We previously characterized a homology-dependent silencing mechanism referred to as the trans-silencing effect (TSE), involved in P-transposable-element repression in the germ line. We now show that clusters of P-element-derived transgenes that induce strong TSE can convert other homologous transgene clusters incapable of TSE into strong silencers, which transmit the acquired silencing capacity through 50 generations. The paramutation occurs without any need for chromosome pairing between the paramutagenic and the paramutated loci, and is mediated by maternal inheritance of cytoplasm carrying Piwi-interacting RNAs (piRNAs) homologous to the transgenes. The repression capacity of the paramutated locus is abolished by a loss-of-function mutation of the aubergine gene involved in piRNA biogenesis, but not by a loss-of-function mutation of the Dicer-2 gene involved in siRNA production. The paramutated cluster, previously producing barely detectable levels of piRNAs, is converted into a stable, strong piRNA-producing locus by the paramutation and becomes fully paramutagenic itself. Our work provides a genetic model for the emergence of piRNA loci, as well as for RNA-mediated trans-generational repression of transposable elements.
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Affiliation(s)
- Augustin de Vanssay
- Laboratoire Biologie du Développement, UMR7622, CNRS-Université Pierre et Marie Curie, 9 quai Saint Bernard, 75005 Paris, France
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Cerino Badone F, Amelotti M, Cassani E, Pilu R. Study of Low Phytic Acid1-7 (lpa1-7), a New ZmMRP4 Mutation in Maize. J Hered 2012; 103:598-605. [DOI: 10.1093/jhered/ess014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Brzeski J, Brzeska K. The maze of paramutation: a rough guide to the puzzling epigenetics of paramutation. WILEY INTERDISCIPLINARY REVIEWS-RNA 2011; 2:863-74. [PMID: 21976288 DOI: 10.1002/wrna.97] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Epigenetic mechanisms maintain gene expression states through mitotic and sometimes meiotic cell divisions. Paramutation is an extreme example of epigenetic processes. Not only an established expression state is transmitted through meiosis to the following generations but also an information transfer occurs between alleles and leads to heritable changes in expression state. As a consequence the expression states can rapidly propagate in population, violating Mendelian genetics. Recent findings unraveled an essential role for siRNA-dependent processes in paramutation. Despite significant progress, the overall picture is still puzzling and many important questions remain to be answered.
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Affiliation(s)
- Jan Brzeski
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
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Pilu R. Paramutation: just a curiosity or fine tuning of gene expression in the next generation? Curr Genomics 2011; 12:298-306. [PMID: 22131875 PMCID: PMC3131737 DOI: 10.2174/138920211795860099] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 04/12/2011] [Accepted: 04/12/2011] [Indexed: 12/31/2022] Open
Abstract
Gene silencing is associated with heritable changes in gene expression which occur without changes in DNA sequence. In eukaryotes these phenomena are common and control important processes, such as development, imprinting, viral and transposon sequence silencing, as well as transgene silencing. Among the epigenetic events, paramutation occurs when a silenced allele (named paramutagenic) is able to silence another allele (paramutable) in trans and this change is heritable. The silenced paramutable allele acquires paramutagenic capacity in the next generations. In the 1950s, Alexander Brink described for the first time the phenomenon of paramutation, occurring in maize at the colored1 (r1) gene, a complex locus (encoding myc-homologous transcription factors) that regulates the anthocyanin biosynthetic pathway. Since then, paramutation and paramutation-like interactions have been discovered in other plants and animals, suggesting that they may underlie important mechanisms for gene expression. The molecular bases of these phenomena are unknown. However in some cases, the event of paramutation has been correlated with changes in DNA methylation, chromatin structure and recently several studies suggest that RNA could play a fundamental role. This last consideration is greatly supported by genetic screening for mutants inhibiting paramutation, which allowed the identification of genes involved in RNA-directed transcriptional silencing, although it is possible that proteins are also required for paramutation.The meaning of paramutation in the life cycle and in evolution remains to be determined even though we might conjecture that this phenomenon could be involved in a fast heritability of favourable epigenetic states across generations in a non-Mendelian way.
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Affiliation(s)
- Roberto Pilu
- Dipartimento di Produzione Vegetale, Università degli Studi di Milano, Via Celoria 2, 20133 Milano, Italy
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37
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Mutations in genes controlling the biosynthesis and accumulation of inositol phosphates in seeds. Biochem Soc Trans 2010; 38:689-94. [PMID: 20298244 DOI: 10.1042/bst0380689] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Most of the phosphorus in the resting seed is stored inside protein storage vacuoles as PA (phytic acid; InsP(6)). The biosynthesis and accumulation of PA can be detected beginning from a few days after anthesis and seem to continue during seed development until maturation. The first step in PA biosynthesis is the formation of Ins3P by conversion of glucose 6-phosphate. This is then followed by a sequential and ordered phosphorylation of the remaining five positions of the inositol ring by a number of kinases, resulting in PA. Identification of low-PA mutants in cereals, legumes and Arabidopsis is instrumental for resolving the biosynthetic pathway and identification of genes controlling the accumulation of PA. Mutations in seven genes involved in the metabolism of PA have been identified and characterized among five plant species using induced mutagenesis and insertion elements. Understanding the biosynthetic pathway and genes controlling the accumulation of PA in plant seeds and how PA may balance the free phosphate is of importance for molecular breeding of crop plants, particularly cereals and legumes.
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Badone FC, Cassani E, Landoni M, Doria E, Panzeri D, Lago C, Mesiti F, Nielsen E, Pilu R. The low phytic acid1-241 (lpa1-241) maize mutation alters the accumulation of anthocyanin pigment in the kernel. PLANTA 2010; 231:1189-1199. [PMID: 20191364 DOI: 10.1007/s00425-010-1123-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 02/05/2010] [Indexed: 05/27/2023]
Abstract
The lpa1 mutations in maize are caused by lesions in the ZmMRP4 (multidrug resistance-associated proteins 4) gene. In previous studies (Raboy et al. in Plant Physiol 124:355-368, 2000; Pilu et al. in Theor Appl Genet 107:980-987, 2003a; Shi et al. Nat Biotechnol 25:930-937, 2007), several mutations have been isolated in this locus causing a reduction of phytic acid (myo-inositol-1,2,3,4,5,6-hexakisphosphate, or InsP(6)) content and an equivalent increasing of free phosphate. In particular, the lpa1-241 mutation causes a reduction of up to 90% of phytic acid, associated with strong pleiotropic effects on the whole plant. In this work, we show, for the first time to our knowledge, an interaction between the accumulation of anthocyanin pigments in the kernel and the lpa mutations. In fact the lpa1-241 mutant accumulates a higher level of anthocyanins as compared to wild type either in the embryo (about 3.8-fold) or in the aleurone layer (about 0.3-fold) in a genotype able to accumulate anthocyanin. Furthermore, we demonstrate that these pigments are mislocalised in the cytoplasm, conferring a blue pigmentation of the scutellum, because of the neutral/basic pH of this cellular compartment. As a matter of fact, the propionate treatment, causing a specific acidification of the cytoplasm, restored the red pigmentation of the scutellum in the mutant and expression analysis showed a reduction of ZmMRP3 anthocyanins' transporter gene expression. On the whole, these data strongly suggest a possible interaction between the lpa mutation and anthocyanin accumulation and compartmentalisation in the kernel.
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Arteaga-Vazquez MA, Chandler VL. Paramutation in maize: RNA mediated trans-generational gene silencing. Curr Opin Genet Dev 2010; 20:156-63. [PMID: 20153628 DOI: 10.1016/j.gde.2010.01.008] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2009] [Revised: 01/18/2010] [Accepted: 01/22/2010] [Indexed: 11/29/2022]
Abstract
Paramutation involves trans-interactions between alleles or homologous sequences that establish distinct gene expression states that are heritable for generations. It was first described in maize by Alexander Brink in the 1950s, with his studies of the red1 (r1) locus. Since that time, paramutation-like phenomena have been reported in other maize genes, other plants, fungi, and animals. Paramutation can occur between endogenous genes, two transgenes or an endogenous gene, and transgene. Recent results indicate that paramutation involves RNA-mediated heritable chromatin changes and a number of genes implicated in RNAi pathways. However, not all aspects of paramutation can be explained by known mechanisms of RNAi-mediated transcriptional silencing.
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Sidorenko L, Dorweiler JE, Cigan AM, Arteaga-Vazquez M, Vyas M, Kermicle J, Jurcin D, Brzeski J, Cai Y, Chandler VL. A dominant mutation in mediator of paramutation2, one of three second-largest subunits of a plant-specific RNA polymerase, disrupts multiple siRNA silencing processes. PLoS Genet 2009; 5:e1000725. [PMID: 19936058 PMCID: PMC2774164 DOI: 10.1371/journal.pgen.1000725] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2009] [Accepted: 10/15/2009] [Indexed: 01/03/2023] Open
Abstract
Paramutation involves homologous sequence communication that leads to meiotically heritable transcriptional silencing. We demonstrate that mop2 (mediator of paramutation2), which alters paramutation at multiple loci, encodes a gene similar to Arabidopsis NRPD2/E2, the second-largest subunit of plant-specific RNA polymerases IV and V. In Arabidopsis, Pol-IV and Pol-V play major roles in RNA-mediated silencing and a single second-largest subunit is shared between Pol-IV and Pol-V. Maize encodes three second-largest subunit genes: all three genes potentially encode full length proteins with highly conserved polymerase domains, and each are expressed in multiple overlapping tissues. The isolation of a recessive paramutation mutation in mop2 from a forward genetic screen suggests limited or no functional redundancy of these three genes. Potential alternative Pol-IV/Pol-V-like complexes could provide maize with a greater diversification of RNA-mediated transcriptional silencing machinery relative to Arabidopsis. Mop2-1 disrupts paramutation at multiple loci when heterozygous, whereas previously silenced alleles are only up-regulated when Mop2-1 is homozygous. The dramatic reduction in b1 tandem repeat siRNAs, but no disruption of silencing in Mop2-1 heterozygotes, suggests the major role for tandem repeat siRNAs is not to maintain silencing. Instead, we hypothesize the tandem repeat siRNAs mediate the establishment of the heritable silent state-a process fully disrupted in Mop2-1 heterozygotes. The dominant Mop2-1 mutation, which has a single nucleotide change in a domain highly conserved among all polymerases (E. coli to eukaryotes), disrupts both siRNA biogenesis (Pol-IV-like) and potentially processes downstream (Pol-V-like). These results suggest either the wild-type protein is a subunit in both complexes or the dominant mutant protein disrupts both complexes. Dominant mutations in the same domain in E. coli RNA polymerase suggest a model for Mop2-1 dominance: complexes containing Mop2-1 subunits are non-functional and compete with wild-type complexes.
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Affiliation(s)
- Lyudmila Sidorenko
- Department of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Jane E. Dorweiler
- Department of Biological Sciences, Marquette University, Milwaukee, Wisconsin, United States of America
| | - A. Mark Cigan
- Pioneer Hi-Bred International, Johnston, Iowa, United States of America
| | - Mario Arteaga-Vazquez
- Department of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Meenal Vyas
- Department of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Jerry Kermicle
- Genetics Department, University of Wisconsin, Madison, Wisconsin, United States of America
| | - Diane Jurcin
- Department of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Jan Brzeski
- Department of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Yu Cai
- Department of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
| | - Vicki L. Chandler
- Department of Plant Sciences, University of Arizona, Tucson, Arizona, United States of America
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RNA-dependent RNA polymerase is required for enhancer-mediated transcriptional silencing associated with paramutation at the maize p1 gene. Genetics 2008; 180:1983-93. [PMID: 18845841 DOI: 10.1534/genetics.108.095281] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Paramutation is the ability of an endogenous gene or a transgene to heritably silence another closely related allele or gene. At the maize p1 (pericarp color1) gene, paramutation is associated with decreases in transcript levels and reduced pigmentation of the endogenous allele that normally specifies red seed coat (pericarp) and cob pigmentation. Herein we demonstrate that this silencing occurs at the transcriptional level and that a specific enhancer fragment from p1 is sufficient to induce all aspects of paramutation. Further, we demonstrate that a mutation in the mop1 gene (mediator of paramutation1), which encodes a RNA-dependent RNA polymerase, is absolutely required for establishing the silencing associated with p1 paramutation. In contrast to its effects on other paramutation loci, the mop1 mutation does not immediately reactivate a previously silenced allele; several generations in the presence of the mop1 mutation are required. In addition, the mop1 mutation was also able to release tissue-specific silencing of another p1 allele that does not participate in paramutation, but does contain a tandem repeated structure and is likely regulated through epigenetic mechanisms. These results demonstrate that RNA-mediated gene-silencing mechanisms play key roles in p1 paramutation and the spectrum of roles for MOP1 is broadened to include tissue-specific expression patterns.
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