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Florez-Rueda AM, Miguel CM, Figueiredo DD. Comparative transcriptomics of seed nourishing tissues: uncovering conserved and divergent pathways in seed plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:1134-1157. [PMID: 38709819 DOI: 10.1111/tpj.16786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 04/04/2024] [Accepted: 04/12/2024] [Indexed: 05/08/2024]
Abstract
The evolutionary and ecological success of spermatophytes is intrinsically linked to the seed habit, which provides a protective environment for the initial development of the new generation. This environment includes an ephemeral nourishing tissue that supports embryo growth. In gymnosperms this tissue originates from the asexual proliferation of the maternal megagametophyte, while in angiosperms it is a product of fertilization, and is called the endosperm. The emergence of these nourishing tissues is of profound evolutionary value, and they are also food staples for most of the world's population. Here, using Orthofinder to infer orthologue genes among newly generated and previously published datasets, we provide a comparative transcriptomic analysis of seed nourishing tissues from species of several angiosperm clades, including those of early diverging lineages, as well as of one gymnosperm. Our results show that, although the structure and composition of seed nourishing tissues has seen significant divergence along evolution, there are signatures that are conserved throughout the phylogeny. Conversely, we identified processes that are specific to species within the clades studied, and thus illustrate their functional divergence. With this, we aimed to provide a foundation for future studies on the evolutionary history of seed nourishing structures, as well as a resource for gene discovery in future functional studies.
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Affiliation(s)
- Ana Marcela Florez-Rueda
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, Am Mühlenberg 1, 14476, Potsdam, Germany
- University of Potsdam, Karl-Liebknechts-Str. 24-25, Haus 26, 14476, Potsdam, Germany
| | - Célia M Miguel
- Faculty of Sciences, Biosystems and Integrative Sciences Institute (BioISI), University of Lisbon, Lisboa, Portugal
| | - Duarte D Figueiredo
- Max Planck Institute of Molecular Plant Physiology, Potsdam Science Park, Am Mühlenberg 1, 14476, Potsdam, Germany
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2
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Chow HT, Mosher RA. Small RNA-mediated DNA methylation during plant reproduction. THE PLANT CELL 2023; 35:1787-1800. [PMID: 36651080 DOI: 10.1093/plcell/koad010] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/11/2023] [Accepted: 01/11/2023] [Indexed: 05/30/2023]
Abstract
Reproductive tissues are a rich source of small RNAs, including several classes of short interfering (si)RNAs that are restricted to this stage of development. In addition to RNA polymerase IV-dependent 24-nt siRNAs that trigger canonical RNA-directed DNA methylation, abundant reproductive-specific siRNAs are produced from companion cells adjacent to the developing germ line or zygote and may move intercellularly before inducing methylation. In some cases, these siRNAs are produced via non-canonical biosynthesis mechanisms or from sequences with little similarity to transposons. While the precise role of these siRNAs and the methylation they trigger is unclear, they have been implicated in specifying a single megaspore mother cell, silencing transposons in the male germ line, mediating parental dosage conflict to ensure proper endosperm development, hypermethylation of mature embryos, and trans-chromosomal methylation in hybrids. In this review, we summarize the current knowledge of reproductive siRNAs, including their biosynthesis, transport, and function.
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Affiliation(s)
- Hiu Tung Chow
- The School of Plant Sciences, The University of Arizona, Tucson, Arizona 85721-0036, USA
| | - Rebecca A Mosher
- The School of Plant Sciences, The University of Arizona, Tucson, Arizona 85721-0036, USA
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3
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Rodrigues JA, Hsieh PH, Ruan D, Nishimura T, Sharma MK, Sharma R, Ye X, Nguyen ND, Nijjar S, Ronald PC, Fischer RL, Zilberman D. Divergence among rice cultivars reveals roles for transposition and epimutation in ongoing evolution of genomic imprinting. Proc Natl Acad Sci U S A 2021; 118:e2104445118. [PMID: 34272287 PMCID: PMC8307775 DOI: 10.1073/pnas.2104445118] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Parent-of-origin-dependent gene expression in mammals and flowering plants results from differing chromatin imprints (genomic imprinting) between maternally and paternally inherited alleles. Imprinted gene expression in the endosperm of seeds is associated with localized hypomethylation of maternally but not paternally inherited DNA, with certain small RNAs also displaying parent-of-origin-specific expression. To understand the evolution of imprinting mechanisms in Oryza sativa (rice), we analyzed imprinting divergence among four cultivars that span both japonica and indica subspecies: Nipponbare, Kitaake, 93-11, and IR64. Most imprinted genes are imprinted across cultivars and enriched for functions in chromatin and transcriptional regulation, development, and signaling. However, 4 to 11% of imprinted genes display divergent imprinting. Analyses of DNA methylation and small RNAs revealed that endosperm-specific 24-nt small RNA-producing loci show weak RNA-directed DNA methylation, frequently overlap genes, and are imprinted four times more often than genes. However, imprinting divergence most often correlated with local DNA methylation epimutations (9 of 17 assessable loci), which were largely stable within subspecies. Small insertion/deletion events and transposable element insertions accompanied 4 of the 9 locally epimutated loci and associated with imprinting divergence at another 4 of the remaining 8 loci. Correlating epigenetic and genetic variation occurred at key regulatory regions-the promoter and transcription start site of maternally biased genes, and the promoter and gene body of paternally biased genes. Our results reinforce models for the role of maternal-specific DNA hypomethylation in imprinting of both maternally and paternally biased genes, and highlight the role of transposition and epimutation in rice imprinting evolution.
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Affiliation(s)
- Jessica A Rodrigues
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Ping-Hung Hsieh
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Deling Ruan
- Department of Plant Pathology, University of California, Davis, CA 95616
| | - Toshiro Nishimura
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Manoj K Sharma
- Department of Plant Pathology, University of California, Davis, CA 95616
| | - Rita Sharma
- Department of Plant Pathology, University of California, Davis, CA 95616
| | - XinYi Ye
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Nicholas D Nguyen
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Sukhranjan Nijjar
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Pamela C Ronald
- Department of Plant Pathology, University of California, Davis, CA 95616
- The Genome Center, University of California, Davis, CA 95616
| | - Robert L Fischer
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720;
| | - Daniel Zilberman
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720;
- Department of Cell and Developmental Biology, The John Innes Centre, Norwich NR4 7UH, United Kingdom
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4
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Liu Y, Jing X, Zhang H, Xiong J, Qiao Y. Identification of Imprinted Genes Based on Homology: An Example of Fragaria vesca. Genes (Basel) 2021; 12:genes12030380. [PMID: 33800118 PMCID: PMC7999015 DOI: 10.3390/genes12030380] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 02/28/2021] [Accepted: 03/04/2021] [Indexed: 01/04/2023] Open
Abstract
Genomic imprinting has drawn increasing attention in plant biology in recent years. At present, hundreds of imprinted genes have been identified in various plants, and some of them have been reported to be evolutionarily conserved in plant species. In this research, 17 candidate genes in Fragaria vesca were obtained based on the homologous imprinted genes in Arabidopsis thaliana and other species. We further constructed reciprocal crosses of diploid strawberry (F. vesca) using the varieties 10-41 and 18-86 as the parents to investigate the conservation of these imprinted genes. Potentially informative single nucleotide polymorphisms (SNPs) were used as molecular markers of two parents obtained from candidate imprinted genes which have been cloned and sequenced. Meanwhile, we analyzed the SNP site variation ratios and parent-of-origin expression patterns of candidate imprinted genes at 10 days after pollination (DAP) endosperm and embryo for the hybrids of reciprocal cross, respectively. A total of five maternally expressed genes (MEGs), i.e., FvARI8, FvKHDP-2, FvDRIP2, FvBRO1, and FvLTP3, were identified in the endosperm, which did not show imprinting in the embryo. Finally, tissues expression analysis indicated that the five imprinted genes excluding FvDRIP2 mainly expressed in the endosperm. This is the first report on imprinted genes of Fragaria, and we provide a simple and rapid method based on homologous conservation to screen imprinted genes. The present study will provide a basis for further study of function and mechanism of genomic imprinting in F. vesca.
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5
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Yu J, Xu F, Wei Z, Zhang X, Chen T, Pu L. Epigenomic landscape and epigenetic regulation in maize. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2020; 133:1467-1489. [PMID: 31965233 DOI: 10.1007/s00122-020-03549-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2019] [Accepted: 01/14/2020] [Indexed: 05/12/2023]
Abstract
Epigenetic regulation has been implicated in the control of multiple agronomic traits in maize. Here, we review current advances in our understanding of epigenetic regulation, which has great potential for improving agronomic traits and the environmental adaptability of crops. Epigenetic regulation plays vital role in the control of complex agronomic traits. Epigenetic variation could contribute to phenotypic diversity and can be used to improve the quality and productivity of crops. Maize (Zea mays L.), one of the most widely cultivated crops for human food, animal feed, and ethanol biofuel, is a model plant for genetic studies. Recent advances in high-throughput sequencing technology have made possible the study of epigenetic regulation in maize on a genome-wide scale. In this review, we discuss recent epigenetic studies in maize many achieved by Chinese research groups. These studies have explored the roles of DNA methylation, posttranslational modifications of histones, chromatin remodeling, and noncoding RNAs in the regulation of gene expression in plant development and environment response. We also provide our future prospects for manipulating epigenetic regulation to improve crops.
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Affiliation(s)
- Jia Yu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Fan Xu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Ziwei Wei
- School of Life Sciences, Anhui Agricultural University, Hefei, China
| | - Xiangxiang Zhang
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Tao Chen
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Li Pu
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China.
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6
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Crisp PA, Hammond R, Zhou P, Vaillancourt B, Lipzen A, Daum C, Barry K, de Leon N, Buell CR, Kaeppler SM, Meyers BC, Hirsch CN, Springer NM. Variation and Inheritance of Small RNAs in Maize Inbreds and F1 Hybrids. PLANT PHYSIOLOGY 2020; 182:318-331. [PMID: 31575624 PMCID: PMC6945832 DOI: 10.1104/pp.19.00817] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/23/2019] [Indexed: 05/20/2023]
Abstract
Small RNAs (sRNAs) regulate gene expression, play important roles in epigenetic pathways, and are hypothesized to contribute to hybrid vigor in plants. Prior investigations have provided valuable insights into associations between sRNAs and heterosis, often using a single hybrid genotype or tissue, but our understanding of the role of sRNAs and their potential value to plant breeding are limited by an incomplete picture of sRNA variation between diverse genotypes and development stages. Here, we provide a deep exploration of sRNA variation and inheritance among a panel of 108 maize (Zea mays) samples spanning five tissues from eight inbred parents and 12 hybrid genotypes, covering a spectrum of heterotic groups, genetic variation, and levels of heterosis for various traits. We document substantial developmental and genotypic influences on sRNA expression, with varying patterns for 21-nucleotide (nt), 22-nt, and 24-nt sRNAs. We provide a detailed view of the distribution of sRNAs in the maize genome, revealing a complex makeup that also shows developmental plasticity, particularly for 22-nt sRNAs. sRNAs exhibited substantially more variation between inbreds as compared with observed variation for gene expression. In hybrids, we identify locus-specific examples of nonadditive inheritance, mostly characterized as partial or complete dominance, but rarely outside the parental range. However, the global abundance of 21-nt, 22-nt, and 24-nt sRNAs varies very little between inbreds and hybrids, suggesting that hybridization affects sRNA expression principally at specific loci rather than on a global scale. This study provides a valuable resource for understanding the potential role of sRNAs in hybrid vigor.
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Affiliation(s)
- Peter A Crisp
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108
| | - Reza Hammond
- Center for Bioinformatics and Computational Biology, University of Delaware, Newark, Delaware 19711
| | - Peng Zhou
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108
| | - Brieanne Vaillancourt
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Anna Lipzen
- United States Department of Energy Joint Genome Institute, Walnut Creek, California 94598
| | - Chris Daum
- United States Department of Energy Joint Genome Institute, Walnut Creek, California 94598
| | - Kerrie Barry
- United States Department of Energy Joint Genome Institute, Walnut Creek, California 94598
| | - Natalia de Leon
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706
| | - C Robin Buell
- Department of Plant Biology, Michigan State University, East Lansing, Michigan 48824
| | - Shawn M Kaeppler
- Department of Agronomy, University of Wisconsin, Madison, Wisconsin 53706
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
- Division of Plant Sciences, University of Missouri, Columbia, Missouri 65211
| | - Candice N Hirsch
- Department of Agronomy and Plant Genetics, University of Minnesota, St. Paul, Minnesota 55108
| | - Nathan M Springer
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota 55108
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7
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Han Q, Bartels A, Cheng X, Meyer A, An YQC, Hsieh TF, Xiao W. Epigenetics Regulates Reproductive Development in Plants. PLANTS 2019; 8:plants8120564. [PMID: 31810261 PMCID: PMC6963493 DOI: 10.3390/plants8120564] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Revised: 11/23/2019] [Accepted: 11/27/2019] [Indexed: 12/20/2022]
Abstract
Seed, resulting from reproductive development, is the main nutrient source for human beings, and reproduction has been intensively studied through genetic, molecular, and epigenetic approaches. However, how different epigenetic pathways crosstalk and integrate to regulate seed development remains unknown. Here, we review the recent progress of epigenetic changes that affect chromatin structure, such as DNA methylation, polycomb group proteins, histone modifications, and small RNA pathways in regulating plant reproduction. In gametogenesis of flowering plants, epigenetics is dynamic between the companion cell and gametes. Cytosine DNA methylation occurs in CG, CHG, CHH contexts (H = A, C, or T) of genes and transposable elements, and undergoes dynamic changes during reproduction. Cytosine methylation in the CHH context increases significantly during embryogenesis, reaches the highest levels in mature embryos, and decreases as the seed germinates. Polycomb group proteins are important transcriptional regulators during seed development. Histone modifications and small RNA pathways add another layer of complexity in regulating seed development. In summary, multiple epigenetic pathways are pivotal in regulating seed development. It remains to be elucidated how these epigenetic pathways interplay to affect dynamic chromatin structure and control reproduction.
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Affiliation(s)
- Qiang Han
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA (A.B.); (X.C.)
| | - Arthur Bartels
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA (A.B.); (X.C.)
| | - Xi Cheng
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA (A.B.); (X.C.)
| | - Angela Meyer
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA (A.B.); (X.C.)
- Department of Biochemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Yong-Qiang Charles An
- US Department of Agriculture, Agricultural Research Service, Midwest Area, Plant Genetics Research Unit, Donald Danforth Plant Science Center, MO 63132, USA;
| | - Tzung-Fu Hsieh
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC 27695, USA;
- Plants for Human Health Institute, North Carolina State University, North Carolina Research Campus, Kannapolis, NC 28081, USA
| | - Wenyan Xiao
- Department of Biology, Saint Louis University, St. Louis, MO 63103, USA (A.B.); (X.C.)
- Correspondence: ; Tel.: +1-314-977-2547
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8
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Castelli S, Mascheretti I, Cosentino C, Lazzari B, Pirona R, Ceriotti A, Viotti A, Lauria M. Uniparental and transgressive expression of α-zeins in maize endosperm of o2 hybrid lines. PLoS One 2018; 13:e0206993. [PMID: 30439980 PMCID: PMC6237297 DOI: 10.1371/journal.pone.0206993] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Accepted: 10/23/2018] [Indexed: 11/18/2022] Open
Abstract
The α-zein gene family encodes the most abundant storage proteins of maize (Zea mays) endosperm. Members of this family are expressed in a parent-of-origin manner. To characterize this phenomenon further, we investigated the expression of a subset of α-zein polypeptides in reciprocal crosses between o2 lines that were characterized by a simplified α-zein pattern. Maize lines that suppressed the expression of α-zeins when used as female parents were identified. The suppression was cross-specific, occurring only when specific genetic backgrounds were combined. Four α-zein sequences that were sensitive to uniparental expression were isolated. Molecular characterization of these α-zeins confirmed that their expression or suppression depended on the genetic proprieties of the endosperm tissue instead of their parental origin. DNA methylation analysis of both maternally and paternally expressed α-zeins revealed no clear correlation between this epigenetic marker and parent-of-origin allelic expression, suggesting that an additional factor(s) is involved in this process. Genetic analyses revealed that the ability of certain lines to suppress α-zein expression was unstable after one round of heterozygosity with non-suppressing lines. Interestingly, α-zeins also showed a transgressive expression pattern because unexpressed isoforms were reactivated in both F2 and backcross plants. Collectively, our results suggest that parent-of-origin expression of specific α-zein alleles depends on a complex interaction between genotypes in a manner that is reminiscent of paramutation-like phenomena.
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Affiliation(s)
- Silvana Castelli
- Istituto di Biologia e Biotecnologia Agraria, CNR, Via Alfonso Corti, Milano, Italy
| | - Iride Mascheretti
- Istituto di Biologia e Biotecnologia Agraria, CNR, Via Alfonso Corti, Milano, Italy
| | - Cristian Cosentino
- Istituto di Biologia e Biotecnologia Agraria, CNR, Via Alfonso Corti, Milano, Italy
| | - Barbara Lazzari
- Istituto di Biologia e Biotecnologia Agraria, CNR, Via Alfonso Corti, Milano, Italy
| | - Raul Pirona
- Istituto di Biologia e Biotecnologia Agraria, CNR, Via Alfonso Corti, Milano, Italy
| | - Aldo Ceriotti
- Istituto di Biologia e Biotecnologia Agraria, CNR, Via Alfonso Corti, Milano, Italy
| | - Angelo Viotti
- Istituto di Biologia e Biotecnologia Agraria, CNR, Via Alfonso Corti, Milano, Italy
- * E-mail: (AV); (ML)
| | - Massimiliano Lauria
- Istituto di Biologia e Biotecnologia Agraria, CNR, Via Alfonso Corti, Milano, Italy
- * E-mail: (AV); (ML)
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9
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Erdmann RM, Satyaki PRV, Klosinska M, Gehring M. A Small RNA Pathway Mediates Allelic Dosage in Endosperm. Cell Rep 2018; 21:3364-3372. [PMID: 29262317 DOI: 10.1016/j.celrep.2017.11.078] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 09/18/2017] [Accepted: 11/21/2017] [Indexed: 12/12/2022] Open
Abstract
Balance between maternal and paternal genomes within the triploid endosperm is necessary for normal seed development. The majority of endosperm genes are expressed in a 2:1 maternal:paternal ratio, reflecting genomic DNA content. Here, we find that the 2:1 transcriptional ratio is, unexpectedly, actively regulated. In A. thaliana and A. lyrata, endosperm 24-nt small RNAs are reduced in transposable elements and enriched in genes compared with the embryo. We find an inverse relationship between the parent of origin of sRNAs and mRNAs, with genes more likely to be associated with maternally than paternally biased sRNAs. Disruption of the Pol IV sRNA pathway causes a shift toward maternal allele mRNA expression for many genes. Furthermore, paternal inheritance of an RNA Pol IV mutation is sufficient to rescue seed abortion caused by excess paternal genome dosage. Thus, RNA Pol IV mediates the transcriptional balance between maternally and paternally inherited genomes in endosperm.
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Affiliation(s)
- Robert M Erdmann
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Maja Klosinska
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Mary Gehring
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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10
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Abstract
The maize endosperm consists of three major compartmentalized cell types: the starchy endosperm (SE), the basal endosperm transfer cell layer (BETL), and the aleurone cell layer (AL). Differential genetic programs are activated in each cell type to construct functionally and structurally distinct cells. To compare gene expression patterns involved in maize endosperm cell differentiation, we isolated transcripts from cryo-dissected endosperm specimens enriched with BETL, AL, or SE at 8, 12, and 16 days after pollination (DAP). We performed transcriptome profiling of coding and long noncoding transcripts in the three cell types during differentiation and identified clusters of the transcripts exhibiting spatio-temporal specificities. Our analysis uncovered that the BETL at 12 DAP undergoes the most dynamic transcriptional regulation for both coding and long noncoding transcripts. In addition, our transcriptome analysis revealed spatio-temporal regulatory networks of transcription factors, imprinted genes, and loci marked with histone H3 trimethylated at lysine 27. Our study suggests that various regulatory mechanisms contribute to the genetic networks specific to the functions and structures of the cell types of the endosperm.
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11
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Rodrigues AS, Miguel CM. The pivotal role of small non-coding RNAs in the regulation of seed development. PLANT CELL REPORTS 2017; 36:653-667. [PMID: 28289886 DOI: 10.1007/s00299-017-2120-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/09/2017] [Indexed: 05/27/2023]
Abstract
Seeds represent a crucial stage of the seed plants life cycle. It is during seed development that the foundations of the future plant body, and the ability to give rise to a new plant capable of growing under sometimes adverse environmental conditions, are established. Small non-coding RNAs are major regulators of gene expression both at the post-transcriptional and transcriptional levels and, not surprisingly, these elements play major roles in seed development and germination. We review here the current knowledge about small RNA expression and functions in seed development, going from the morphogenesis phase comprehending embryo development and patterning, to the several steps of the maturation phase, ending in the transition to the germination. A special focus is given to the small RNAs for which functional studies have been conducted and their participation in regulatory networks operating in seeds. Many challenges remain ahead for dissecting the complex small RNA landscape in seeds, but this is a highly relevant issue in plant biology and advances in this area will most certainly impact plant breeding.
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Affiliation(s)
- Andreia S Rodrigues
- Instituto de Biologia Experimental e Tecnológica (iBET), Apartado 12, 2780-901, Oeiras, Portugal
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Av. da República, 2780-157, Oeiras, Portugal
| | - Célia M Miguel
- Instituto de Biologia Experimental e Tecnológica (iBET), Apartado 12, 2780-901, Oeiras, Portugal.
- Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa (ITQB NOVA), Av. da República, 2780-157, Oeiras, Portugal.
- Biosystems & Integrative Sciences Institute, Faculdade de Ciências, Universidade de Lisboa (FCUL), Campo Grande, 1749-016, Lisbon, Portugal.
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12
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Martinez G, Köhler C. Role of small RNAs in epigenetic reprogramming during plant sexual reproduction. CURRENT OPINION IN PLANT BIOLOGY 2017; 36:22-28. [PMID: 28088028 DOI: 10.1016/j.pbi.2016.12.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 12/29/2016] [Indexed: 05/07/2023]
Abstract
Sexual reproduction, the formation of a new individual from specialized reproductive cells after fertilization, involves the precise orchestration of different developmental and genomic processes. These processes are to a large extent governed by small RNAs (sRNAs) that either belong to the class of micro RNAs (miRNAs) or small-interfering RNAs (siRNAs). The latter are derived from transposable elements (TEs) and involved in genome defense and transgenerational inheritance of heterochromatin identity, ensuring genome stability. Remarkably, male and female gametophytes employ sRNAs to ensure reproductive success, but the underlying processes of their formation and action differ. Here, we review current advances in the field concerning the roles of sRNAs during flowering plant (angiosperm) reproduction and pinpoint where further research is required to solve open questions.
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Affiliation(s)
- German Martinez
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden.
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13
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Wang G, Köhler C. Epigenetic processes in flowering plant reproduction. JOURNAL OF EXPERIMENTAL BOTANY 2017; 68:797-807. [PMID: 28062591 DOI: 10.1093/jxb/erw486] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Seeds provide up to 70% of the energy intake of the human population, emphasizing the relevance of understanding the genetic and epigenetic mechanisms controlling seed formation. In flowering plants, seeds are the product of a double fertilization event, leading to the formation of the embryo and the endosperm surrounded by maternal tissues. Analogous to mammals, plants undergo extensive epigenetic reprogramming during both gamete formation and early seed development, a process that is supposed to be required to enforce silencing of transposable elements and thus to maintain genome stability. Global changes of DNA methylation, histone modifications, and small RNAs are closely associated with epigenome programming during plant reproduction. Here, we review current knowledge on chromatin changes occurring during sporogenesis and gametogenesis, as well as early seed development in major flowering plant models.
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Affiliation(s)
- Guifeng Wang
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
- Shanghai Key Laboratory of Bio-Energy Crops, School of Life Sciences, Shanghai University, Shanghai 200444, China
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
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Satyaki PRV, Gehring M. DNA methylation and imprinting in plants: machinery and mechanisms. Crit Rev Biochem Mol Biol 2017; 52:163-175. [PMID: 28118754 DOI: 10.1080/10409238.2017.1279119] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Imprinting is an epigenetic phenomenon in which genes are expressed selectively from either the maternal or paternal alleles. In plants, imprinted gene expression is found in a tissue called the endosperm. Imprinting is often set by a unique epigenomic configuration in which the maternal chromosomes are less DNA methylated than their paternal counterparts. In this review, we synthesize studies that paint a detailed molecular portrait of the distinctive endosperm methylome. We will also discuss the molecular machinery that shapes and modifies this methylome, and the role of DNA methylation in imprinting.
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Affiliation(s)
- P R V Satyaki
- a Whitehead Institute for Biomedical Research , Cambridge , MA , USA
| | - Mary Gehring
- a Whitehead Institute for Biomedical Research , Cambridge , MA , USA.,b Department of Biology , Massachusetts Institute of Technology , Cambridge , MA , USA
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15
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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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16
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Abstract
Genomic imprinting, an inherently epigenetic phenomenon defined by parent of origin-dependent gene expression, is observed in mammals and flowering plants. Genome-scale surveys of imprinted expression and the underlying differential epigenetic marks have led to the discovery of hundreds of imprinted plant genes and confirmed DNA and histone methylation as key regulators of plant imprinting. However, the biological roles of the vast majority of imprinted plant genes are unknown, and the evolutionary forces shaping plant imprinting remain rather opaque. Here, we review the mechanisms of plant genomic imprinting and discuss theories of imprinting evolution and biological significance in light of recent findings.
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Affiliation(s)
- Jessica A Rodrigues
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, California 94720, USA
| | - Daniel Zilberman
- Department of Plant and Microbial Biology, University of California at Berkeley, Berkeley, California 94720, USA
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17
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Lunardon A, Forestan C, Farinati S, Axtell MJ, Varotto S. Genome-Wide Characterization of Maize Small RNA Loci and Their Regulation in the required to maintain repression6-1 (rmr6-1) Mutant and Long-Term Abiotic Stresses. PLANT PHYSIOLOGY 2016; 170:1535-48. [PMID: 26747286 PMCID: PMC4775107 DOI: 10.1104/pp.15.01205] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Accepted: 01/04/2016] [Indexed: 05/03/2023]
Abstract
Endogenous small RNAs (sRNAs) contribute to gene regulation and genome homeostasis, but their activities and functions are incompletely known. The maize genome has a high number of transposable elements (TEs; almost 85%), some of which spawn abundant sRNAs. We performed sRNA and total RNA sequencing from control and abiotically stressed B73 wild-type plants and rmr6-1 mutants. RMR6 encodes the largest subunit of the RNA polymerase IV complex and is responsible for accumulation of most 24-nucleotide (nt) small interfering RNAs (siRNAs). We identified novel MIRNA loci and verified miR399 target conservation in maize. RMR6-dependent 23-24 nt siRNA loci were specifically enriched in the upstream region of the most highly expressed genes. Most genes misregulated in rmr6-1 did not show a significant correlation with loss of flanking siRNAs, but we identified one gene supporting existing models of direct gene regulation by TE-derived siRNAs. Long-term drought correlated with changes of miRNA and sRNA accumulation, in particular inducing down-regulation of a set of sRNA loci in the wild-typeleaf.
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Affiliation(s)
- Alice Lunardon
- Department of Agronomy, Animals, Food, Natural Resources and Environment, University of Padova, Agripolis Viale dell'Università 16, 35020 Legnaro PD Italy (A.L., C.F., S.F., S.V.); andDepartment of Biology and Huck Institutes of the Life Sciences, Penn State University, University Park, Pennsylvania 16802 (A.L., M.J.A.)
| | - Cristian Forestan
- Department of Agronomy, Animals, Food, Natural Resources and Environment, University of Padova, Agripolis Viale dell'Università 16, 35020 Legnaro PD Italy (A.L., C.F., S.F., S.V.); andDepartment of Biology and Huck Institutes of the Life Sciences, Penn State University, University Park, Pennsylvania 16802 (A.L., M.J.A.)
| | - Silvia Farinati
- Department of Agronomy, Animals, Food, Natural Resources and Environment, University of Padova, Agripolis Viale dell'Università 16, 35020 Legnaro PD Italy (A.L., C.F., S.F., S.V.); andDepartment of Biology and Huck Institutes of the Life Sciences, Penn State University, University Park, Pennsylvania 16802 (A.L., M.J.A.)
| | - Michael J Axtell
- Department of Agronomy, Animals, Food, Natural Resources and Environment, University of Padova, Agripolis Viale dell'Università 16, 35020 Legnaro PD Italy (A.L., C.F., S.F., S.V.); andDepartment of Biology and Huck Institutes of the Life Sciences, Penn State University, University Park, Pennsylvania 16802 (A.L., M.J.A.)
| | - Serena Varotto
- Department of Agronomy, Animals, Food, Natural Resources and Environment, University of Padova, Agripolis Viale dell'Università 16, 35020 Legnaro PD Italy (A.L., C.F., S.F., S.V.); andDepartment of Biology and Huck Institutes of the Life Sciences, Penn State University, University Park, Pennsylvania 16802 (A.L., M.J.A.)
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18
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Xin M, Yang G, Yao Y, Peng H, Hu Z, Sun Q, Wang X, Ni Z. Temporal small RNA transcriptome profiling unraveled partitioned miRNA expression in developing maize endosperms between reciprocal crosses. FRONTIERS IN PLANT SCIENCE 2015; 6:744. [PMID: 26442057 PMCID: PMC4584948 DOI: 10.3389/fpls.2015.00744] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2015] [Accepted: 08/31/2015] [Indexed: 05/31/2023]
Abstract
In angiosperms, the endosperm nurtures the embryo and provides nutrients for seed germination. To identify the expression pattern of small interfering RNA in the developing maize endosperm, we have performed high-throughput small RNA transcriptome sequencing of kernels at 0, 3, and 5 days after pollination (DAP) and endosperms at 7, 10, and 15 DAP using B73 and Mo17 reciprocal crosses in previous study. Here, we further explored these small RNA-seq data to investigate the potential roles of miRNAs in regulating the gene expression process. In total, 57 conserved miRNAs and 18 novel miRNAs were observed highly expressed in maize endosperm. Temporal expression profiling indicated that these miRNAs exhibited dynamic and partitioned expression patterns at different developmental stages between maize reciprocal crosses, and quantitative RT-PCR results further confirmed our observation. In addition, we found a subset of distinct tandem miRNAs are generated from a single stem-loop structure in maize that might be conserved in monocots. Furthermore, a SNP variation of Zma-miR408-5p at 11th base position was characterized between B73 and Mo17 which might lead to completely different functions in repressing targets. More interestingly, Zma-miR408-5p exhibited B73-biased expression pattern in the B73 and Mo17 reciprocal hybrid endosperms at 7, 10, and 15 DAP according to the reads abundance with SNPs and CAPS experiment. Together, this study suggests that miRNA plays a crucial role in regulating endosperm development, and exhibited distinct expression patterns in developing endosperm between maize reciprocal crosses.
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Affiliation(s)
- Mingming Xin
- *Correspondence: Mingming Xin and Zhongfu Ni, Department of Plant genetics and breeding, China Agricultural University, No. 2 Yuanmingyuan Xi Road, Haidian District, Beijing 100193, China ;
| | | | | | | | | | | | | | - Zhongfu Ni
- *Correspondence: Mingming Xin and Zhongfu Ni, Department of Plant genetics and breeding, China Agricultural University, No. 2 Yuanmingyuan Xi Road, Haidian District, Beijing 100193, China ;
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