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Berthelier J, Furci L, Asai S, Sadykova M, Shimazaki T, Shirasu K, Saze H. Long-read direct RNA sequencing reveals epigenetic regulation of chimeric gene-transposon transcripts in Arabidopsis thaliana. Nat Commun 2023; 14:3248. [PMID: 37277361 DOI: 10.1038/s41467-023-38954-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 05/21/2023] [Indexed: 06/07/2023] Open
Abstract
Transposable elements (TEs) are accumulated in both intergenic and intragenic regions in plant genomes. Intragenic TEs often act as regulatory elements of associated genes and are also co-transcribed with genes, generating chimeric TE-gene transcripts. Despite the potential impact on mRNA regulation and gene function, the prevalence and transcriptional regulation of TE-gene transcripts are poorly understood. By long-read direct RNA sequencing and a dedicated bioinformatics pipeline, ParasiTE, we investigated the transcription and RNA processing of TE-gene transcripts in Arabidopsis thaliana. We identified a global production of TE-gene transcripts in thousands of A. thaliana gene loci, with TE sequences often being associated with alternative transcription start sites or transcription termination sites. The epigenetic state of intragenic TEs affects RNAPII elongation and usage of alternative poly(A) signals within TE sequences, regulating alternative TE-gene isoform production. Co-transcription and inclusion of TE-derived sequences into gene transcripts impact regulation of RNA stability and environmental responses of some loci. Our study provides insights into TE-gene interactions that contributes to mRNA regulation, transcriptome diversity, and environmental responses in plants.
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Grants
- JP20H02995 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP22H00364 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP20H05909 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- JP20H05913 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
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Affiliation(s)
- Jérémy Berthelier
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan.
| | - Leonardo Furci
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Shuta Asai
- Center for Sustainable Resource Science, RIKEN, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Munissa Sadykova
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Tomoe Shimazaki
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Ken Shirasu
- Center for Sustainable Resource Science, RIKEN, 1-7-22 Suehiro-cho, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Hidetoshi Saze
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology Graduate University (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan.
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Jiang Y, Zhang S, Chen K, Xia X, Tao B, Kong W. Impacts of DNA methylases and demethylases on the methylation and expression of Arabidopsis ethylene signal pathway genes. Funct Integr Genomics 2023; 23:143. [PMID: 37127698 DOI: 10.1007/s10142-023-01069-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 04/21/2023] [Accepted: 04/24/2023] [Indexed: 05/03/2023]
Abstract
Arabidopsis ethylene (ET) signal pathway plays important roles in various aspects. Cytosine DNA methylation is significant in controlling gene expression in plants. Here, we analyzed the bisulfite sequencing and mRNA sequencing data from Arabidopsis (de)methylase mutants met1, cmt3, drm1/2, ddm1, ros1-4, and rdd to investigate how DNA (de)methylases influence the DNA methylation and expression of Arabidopsis ET pathway genes. At least 32 genes are found to involved in Arabidopsis ET pathway by text mining. Among them, 14 genes are unmethylated or methylated with very low levels. ACS6 and ACS9 are conspicuously methylated within their upstream regions. The other 16 genes are predominantly methylated at the CG sites within gene body regions in wild-type plants, and mutation of MET1 resulted in almost entire elimination of the CG methylations. In addition, CG methylations within some genes are jointly maintained by MET1 and other (de)methylases. Analyses of mRNA-seq data indicated that some ET pathway genes were differentially expressed between wild-type and diverse mutants. PDF1.2, the marker gene of ET signal pathway, was found being regulated indirectly by the methylases. Eighty-two transposable elements (TEs) were identified to be associated to 15 ET pathway genes. ACS11 is found located in a heterochromatin region that contains 57 TEs, indicating its specific expression and regulation. Together, our results suggest that DNA (de)methylases are implicated in the regulation of CG methylation within gene body regions and transcriptional activity of some ET pathway genes and that maintenance of normal CG methylation is essential for ET pathway in Arabidopsis.
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Affiliation(s)
- Yan Jiang
- School of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Shengwei Zhang
- School of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Kun Chen
- School of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Xue Xia
- School of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Bingqing Tao
- School of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China
| | - Weiwen Kong
- School of Plant Protection, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, 225009, Jiangsu, China.
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3
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Parker MT, Knop K, Zacharaki V, Sherwood AV, Tomé D, Yu X, Martin PGP, Beynon J, Michaels SD, Barton GJ, Simpson GG. Widespread premature transcription termination of Arabidopsis thaliana NLR genes by the spen protein FPA. eLife 2021; 10:e65537. [PMID: 33904405 PMCID: PMC8116057 DOI: 10.7554/elife.65537] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 04/26/2021] [Indexed: 12/18/2022] Open
Abstract
Genes involved in disease resistance are some of the fastest evolving and most diverse components of genomes. Large numbers of nucleotide-binding, leucine-rich repeat (NLR) genes are found in plant genomes and are required for disease resistance. However, NLRs can trigger autoimmunity, disrupt beneficial microbiota or reduce fitness. It is therefore crucial to understand how NLRs are controlled. Here, we show that the RNA-binding protein FPA mediates widespread premature cleavage and polyadenylation of NLR transcripts, thereby controlling their functional expression and impacting immunity. Using long-read Nanopore direct RNA sequencing, we resolved the complexity of NLR transcript processing and gene annotation. Our results uncover a co-transcriptional layer of NLR control with implications for understanding the regulatory and evolutionary dynamics of NLRs in the immune responses of plants.
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Affiliation(s)
- Matthew T Parker
- School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Katarzyna Knop
- School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | | | - Anna V Sherwood
- School of Life Sciences, University of DundeeDundeeUnited Kingdom
| | - Daniel Tomé
- School of Life Sciences, University of WarwickCoventryUnited Kingdom
| | - Xuhong Yu
- Department of Biology, Indiana UniversityBloomingtonUnited States
| | - Pascal GP Martin
- Department of Biology, Indiana UniversityBloomingtonUnited States
| | - Jim Beynon
- School of Life Sciences, University of WarwickCoventryUnited Kingdom
| | - Scott D Michaels
- Department of Biology, Indiana UniversityBloomingtonUnited States
| | | | - Gordon G Simpson
- School of Life Sciences, University of DundeeDundeeUnited Kingdom
- The James Hutton InstituteInvergowrieUnited Kingdom
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4
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Lai Y, Lu XM, Daron J, Pan S, Wang J, Wang W, Tsuchiya T, Holub E, McDowell JM, Slotkin RK, Le Roch KG, Eulgem T. The Arabidopsis PHD-finger protein EDM2 has multiple roles in balancing NLR immune receptor gene expression. PLoS Genet 2020; 16:e1008993. [PMID: 32925902 PMCID: PMC7529245 DOI: 10.1371/journal.pgen.1008993] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2019] [Revised: 10/01/2020] [Accepted: 07/14/2020] [Indexed: 12/19/2022] Open
Abstract
Plant NLR-type receptors serve as sensitive triggers of host immunity. Their expression has to be well-balanced, due to their interference with various cellular processes and dose-dependency of their defense-inducing activity. A genetic “arms race” with fast-evolving pathogenic microbes requires plants to constantly innovate their NLR repertoires. We previously showed that insertion of the COPIA-R7 retrotransposon into RPP7 co-opted the epigenetic transposon silencing signal H3K9me2 to a new function promoting expression of this Arabidopsis thaliana NLR gene. Recruitment of the histone binding protein EDM2 to COPIA-R7-associated H3K9me2 is required for optimal expression of RPP7. By profiling of genome-wide effects of EDM2, we now uncovered additional examples illustrating effects of transposons on NLR gene expression, strongly suggesting that these mobile elements can play critical roles in the rapid evolution of plant NLR genes by providing the “raw material” for gene expression mechanisms. We further found EDM2 to have a global role in NLR expression control. Besides serving as a positive regulator of RPP7 and a small number of other NLR genes, EDM2 acts as a suppressor of a multitude of additional NLR genes. We speculate that the dual functionality of EDM2 in NLR expression control arose from the need to compensate for fitness penalties caused by high expression of some NLR genes by suppression of others. Moreover, we are providing new insights into functional relationships of EDM2 with its interaction partner, the RNA binding protein EDM3/AIPP1, and its target gene IBM1, encoding an H3K9-demethylase. We previously found the Arabidopsis thaliana PHD-finger protein EDM2 to serve as a chromatin-associated factor controlling expression of the NLR-type immune receptor gene RPP7. EDM2 binds to the transposon-silencing signal H3K9me2 and affects levels of this epigenetic mark at various loci. By genome-wide profiling of transcript- and H3K9me2-levels we now found EDM2 to have a broader role in controlling NLR gene expression. In order to mitigate fitness costs caused by its promoting effects on RPP7 expression and that of several other NLR genes, EDM2 seems to suppress expression of many additional members of this gene family. This observation is in line with multiple reports demonstrating the need for balanced expression of NLRs, which can substantially reduce overall plant fitness, but need to be present at certain minimal levels to confer sufficient immune protection. Our previous results demonstrated that the influence of EDM2 on RPP7 expression was co-opted to this immune receptor gene by the insertion of an EDM2-controlled transposon. Here, we are providing additional examples for transposon-associated effects on NLR gene expression, suggesting that these mobile elements play an important role for NLR genes by equipping members of this rapidly evolving gene family with regulatory mechanisms needed for balanced expression.
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Affiliation(s)
- Yan Lai
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, Department of Botany and Plan Sciences, University of California at Riverside, Riverside, CA, United States of America
- College of Life Sciences, Fujian Agricultural and Forestry University, Fuzhou, Fujian, China
| | - Xueqing Maggie Lu
- Center for Infectious Disease and Vector Research, Institute of Integrative Genome Biology, Department of Molecular, Cell and Systems Biology, University of California at Riverside, Riverside, CA, United States of America
| | - Josquin Daron
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Songqin Pan
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, Department of Botany and Plan Sciences, University of California at Riverside, Riverside, CA, United States of America
| | - Jianqiang Wang
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, Department of Botany and Plan Sciences, University of California at Riverside, Riverside, CA, United States of America
| | - Wei Wang
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - Tokuji Tsuchiya
- College of Bioresource Sciences, Nihon University, Kanagawa, Japan
| | - Eric Holub
- School of Life Sciences, University of Warwick, Wellesbourne campus, United Kingdom
| | - John M. McDowell
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA, United States of America
| | - R. Keith Slotkin
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
- Donald Danforth Plant Science Center, St. Louis, Missouri, United States of America
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
| | - Karine G. Le Roch
- Center for Infectious Disease and Vector Research, Institute of Integrative Genome Biology, Department of Molecular, Cell and Systems Biology, University of California at Riverside, Riverside, CA, United States of America
- * E-mail: (KGLR); (TE)
| | - Thomas Eulgem
- Center for Plant Cell Biology, Institute of Integrative Genome Biology, Department of Botany and Plan Sciences, University of California at Riverside, Riverside, CA, United States of America
- * E-mail: (KGLR); (TE)
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Le NT, Harukawa Y, Miura S, Boer D, Kawabe A, Saze H. Epigenetic regulation of spurious transcription initiation in Arabidopsis. Nat Commun 2020; 11:3224. [PMID: 32591528 PMCID: PMC7319988 DOI: 10.1038/s41467-020-16951-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 06/01/2020] [Indexed: 01/01/2023] Open
Abstract
In plants, epigenetic regulation is critical for silencing transposons and maintaining proper gene expression. However, its impact on the genome-wide transcription initiation landscape remains elusive. By conducting a genome-wide analysis of transcription start sites (TSSs) using cap analysis of gene expression (CAGE) sequencing, we show that thousands of TSSs are exclusively activated in various epigenetic mutants of Arabidopsis thaliana and referred to as cryptic TSSs. Many have not been identified in previous studies, of which up to 65% are contributed by transposons. They possess similar genetic features to regular TSSs and their activation is strongly associated with the ectopic recruitment of RNAPII machinery. The activation of cryptic TSSs significantly alters transcription of nearby TSSs, including those of genes important for development and stress responses. Our study, therefore, sheds light on the role of epigenetic regulation in maintaining proper gene functions in plants by suppressing transcription from cryptic TSSs. Epigenetic regulation can silence transposons and maintain gene expression. Here the authors survey Arabidopsis mutants defective in epigenetic regulation and show ectopic activation of thousands of cryptic TSSs and altered expression of nearby genes demonstrating the importance of suppressing spurious transcription.
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Affiliation(s)
- Ngoc Tu Le
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Yoshiko Harukawa
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Saori Miura
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan
| | - Damian Boer
- Wageningen University & Research, Droevendaalsesteeg 4, 6708 PB Wageningen, Netherlands
| | - Akira Kawabe
- Faculty of Life Sciences, Kyoto Sangyo University, Kyoto, 603-8555, Japan
| | - Hidetoshi Saze
- Plant Epigenetics Unit, Okinawa Institute of Science and Technology (OIST), 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa, 904-0495, Japan.
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6
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Deremetz A, Le Roux C, Idir Y, Brousse C, Agorio A, Gy I, Parker JE, Bouché N. Antagonistic Actions of FPA and IBM2 Regulate Transcript Processing from Genes Containing Heterochromatin. PLANT PHYSIOLOGY 2019; 180:392-403. [PMID: 30814131 PMCID: PMC6501070 DOI: 10.1104/pp.18.01106] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 02/21/2019] [Indexed: 05/06/2023]
Abstract
Repressive epigenetic marks, such as DNA and histone methylation, are sometimes located within introns. In Arabidopsis (Arabidopsis thaliana), INCREASE IN BONSAI METHYLATION2 (IBM2), an RNA-binding protein containing a bromo-adjacent homology domain, is required to process functional transcript isoforms of genes carrying intronic heterochromatin. In a genetic screen for suppressors of the ibm2 mutation, we identified FPA, an RNA-binding protein that promotes use of proximal polyadenylation sites in genes targeted by IBM2, including IBM1 encoding an essential H3K9 histone demethylase and the disease resistance gene RECOGNITION OF PERONOSPORA PARASITICA7 Both IBM2 and FPA are involved in the processing of their common mRNA targets: Transcription of IBM2 target genes is restored when FPA is mutated in ibm2 and impaired in transgenic plants overexpressing FPA By contrast, transposons targeted by IBM2 and localized outside introns are not under this antagonistic control. The DNA methylation patterns of some genes and transposons are modified in fpa plants, including the large intron of IBM1, but these changes are rather limited and reversed when the mutant is complemented, indicating that FPA has a restricted role in mediating silencing. These data reveal a complex regulation by IBM2 and FPA pathways in processing mRNAs of genes bearing heterochromatic marks.
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Affiliation(s)
- Aurélie Deremetz
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique, 78000 Versailles, France
- Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Clémentine Le Roux
- Max-Planck Institute for Plant Breeding Research, Department of Plant-Microbe Interactions, D-50829 Cologne, Germany
| | - Yassir Idir
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique, 78000 Versailles, France
- Université Paris-Sud, Université Paris-Saclay, 91405 Orsay, France
| | - Cécile Brousse
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique, 78000 Versailles, France
| | - Astrid Agorio
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique, 78000 Versailles, France
| | - Isabelle Gy
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique, 78000 Versailles, France
| | - Jane E Parker
- Max-Planck Institute for Plant Breeding Research, Department of Plant-Microbe Interactions, D-50829 Cologne, Germany
| | - Nicolas Bouché
- Institut Jean-Pierre Bourgin, Unité Mixte de Recherche 1318, Institut National de la Recherche Agronomique, 78000 Versailles, France
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In silico Analysis of qBFR4 and qLBL5 in Conferring Quantitative Resistance Against Rice Blast. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2018. [DOI: 10.22207/jpam.12.4.03] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
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8
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Yan H, Bombarely A, Xu B, Frazier TP, Wang C, Chen P, Chen J, Hasing T, Cui C, Zhang X, Zhao B, Huang L. siRNAs regulate DNA methylation and interfere with gene and lncRNA expression in the heterozygous polyploid switchgrass. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:208. [PMID: 30061930 PMCID: PMC6058383 DOI: 10.1186/s13068-018-1202-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Accepted: 07/10/2018] [Indexed: 05/14/2023]
Abstract
BACKGROUND Understanding the DNA methylome and its relationship with non-coding RNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), is essential for elucidating the molecular mechanisms underlying key biological processes in plants. Few studies have examined the functional roles of the DNA methylome in grass species with highly heterozygous polyploid genomes. RESULTS We performed genome-wide DNA methylation profiling in the tetraploid switchgrass (Panicum virgatum L.) cultivar 'Alamo' using bisulfite sequencing. Single-base-resolution methylation patterns were observed in switchgrass leaf and root tissues, which allowed for characterization of the relationship between DNA methylation and mRNA, miRNA, and lncRNA populations. The results of this study revealed that siRNAs positively regulate DNA methylation of the mCHH sites surrounding genes, and that DNA methylation interferes with gene and lncRNA expression in switchgrass. Ninety-six genes covered by differentially methylated regions (DMRs) were annotated by GO analysis as being involved in stimulus-related processes. Functionally, 82% (79/96) of these genes were found to be hypomethylated in switchgrass root tissue. Sequencing analysis of lncRNAs identified two lncRNAs that are potential precursors of miRNAs, which are predicted to target genes that function in cellulose biosynthesis, stress regulation, and stem and root development. CONCLUSIONS This study characterized the DNA methylome in switchgrass and elucidated its relevance to gene and non-coding RNAs. These results provide valuable genomic resources and references that will aid further epigenetic research in this important biofuel crop.
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Affiliation(s)
- Haidong Yan
- Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130 China
- Department of Horticulture, Virginia Tech, Blacksburg, VA 24061 USA
| | | | - Bin Xu
- College of Grassland Science, Nanjing Agricultural University, Nanjing, 210095 China
| | - Taylor P. Frazier
- Department of Plant Sciences, University of Tennessee, Knoxville, TN 37996 USA
| | - Chengran Wang
- Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130 China
| | - Peilin Chen
- Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130 China
| | - Jing Chen
- Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130 China
| | - Tomas Hasing
- Department of Horticulture, Virginia Tech, Blacksburg, VA 24061 USA
| | - Chenming Cui
- Department of Plant Pathology, Physiology, and Weed Science, Virginia Tech, Blacksburg, VA 24061 USA
| | - Xinquan Zhang
- Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130 China
| | - Bingyu Zhao
- Department of Horticulture, Virginia Tech, Blacksburg, VA 24061 USA
| | - Linkai Huang
- Department of Grassland Science, Animal Science and Technology College, Sichuan Agricultural University, Chengdu, 611130 China
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Song Q, Guan X, Chen ZJ. Dynamic Roles for Small RNAs and DNA Methylation during Ovule and Fiber Development in Allotetraploid Cotton. PLoS Genet 2015; 11:e1005724. [PMID: 26710171 PMCID: PMC4692501 DOI: 10.1371/journal.pgen.1005724] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 11/14/2015] [Indexed: 11/19/2022] Open
Abstract
DNA methylation is essential for plant and animal development. In plants, methylation occurs at CG, CHG, and CHH (H = A, C or T) sites via distinct pathways. Cotton is an allotetraploid consisting of two progenitor genomes. Each cotton fiber is a rapidly-elongating cell derived from the ovule epidermis, but the molecular basis for this developmental transition is unknown. Here we analyzed methylome, transcriptome, and small RNAome and revealed distinct changes in CHH methylation during ovule and fiber development. In ovules, CHH hypermethylation in promoters correlated positively with siRNAs, inducing RNA-dependent DNA methylation (RdDM), and up-regulation of ovule-preferred genes. In fibers, the ovule-derived cells generated additional heterochromatic CHH hypermethylation independent of RdDM, which repressed transposable elements (TEs) and nearby genes including fiber-related genes. Furthermore, CHG and CHH methylation in genic regions contributed to homoeolog expression bias in ovules and fibers. Inhibiting DNA methylation using 5-aza-2'-deoxycytidine in cultured ovules has reduced fiber cell number and length, suggesting a potential role for DNA methylation in fiber development. Thus, RdDM-dependent methylation in promoters and RdDM-independent methylation in TEs and nearby genes could act as a double-lock feedback mechanism to mediate gene and TE expression, potentiating the transition from epidermal to fiber cells during ovule and seed development. Cotton is the world’s largest source of renewable textile fiber and is an allotetraploid crop consisting of two progenitor genomes. In plants, de novo CHH (H = A, T, or C) methylation depends on RNA-directed DNA methylation (RdDM) and CHROMOMETHYLASE2 (CMT2)-mediated pathways. The biological significance of the two pathways is largely unknown. Here we show dynamic roles of these two pathways in ovule and fiber development. RdDM-dependent CHH methylation is linked to gene activation in ovules, and additional CMT2-dependent methylation leads to silencing of transposons and nearby genes in fibers. Moreover, DNA methylation affects expression bias of homoeologous genes and fiber development. These findings provide novel insights into epigenetic regulation of organ development and polyploid evolution.
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Affiliation(s)
- Qingxin Song
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, Texas, United States of America
| | - Xueying Guan
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, Texas, United States of America
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - Z. Jeffrey Chen
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology, Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, Texas, United States of America
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
- * E-mail:
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10
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Dodsworth S, Leitch AR, Leitch IJ. Genome size diversity in angiosperms and its influence on gene space. Curr Opin Genet Dev 2015; 35:73-8. [PMID: 26605684 DOI: 10.1016/j.gde.2015.10.006] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 10/28/2015] [Accepted: 10/28/2015] [Indexed: 01/02/2023]
Abstract
Genome size varies c. 2400-fold in angiosperms (flowering plants), although the range of genome size is skewed towards small genomes, with a mean genome size of 1C=5.7Gb. One of the most crucial factors governing genome size in angiosperms is the relative amount and activity of repetitive elements. Recently, there have been new insights into how these repeats, previously discarded as 'junk' DNA, can have a significant impact on gene space (i.e. the part of the genome comprising all the genes and gene-related DNA). Here we review these new findings and explore in what ways genome size itself plays a role in influencing how repeats impact genome dynamics and gene space, including gene expression.
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Affiliation(s)
- Steven Dodsworth
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Andrew R Leitch
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London E1 4NS, UK
| | - Ilia J Leitch
- Department of Comparative Plant and Fungal Biology, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3DS, UK.
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11
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Cui X, Cao X. Epigenetic regulation and functional exaptation of transposable elements in higher plants. CURRENT OPINION IN PLANT BIOLOGY 2014; 21:83-88. [PMID: 25061895 DOI: 10.1016/j.pbi.2014.07.001] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 06/23/2014] [Accepted: 07/02/2014] [Indexed: 05/06/2023]
Abstract
Transposable elements (TEs) are mobile genetic elements that can proliferate in their host genomes. Because of their robust amplification, TEs have long been considered 'selfish DNA', harmful insertions that can threaten host genome integrity. The idea of TEs as junk DNA comes from analysis of epigenetic silencing of their mobility in plants and animals. This idea contrasts with McClintock's characterization of TEs as 'controlling elements'. Emerging studies on the regulatory functions of TEs in plant genomes have updated McClintock's characterization, indicating exaptation of TEs for genetic regulation. In this review, we summarize recent progress in TE silencing, particularly in Arabidopsis and rice, and show that TEs provide an abundant, natural source of regulation for the host genome.
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Affiliation(s)
- Xiekui Cui
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xiaofeng Cao
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China.
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Abstract
For decades, transposable elements have been known to produce a wide variety of changes in plant gene expression and function. This has led to the idea that transposable element activity has played a key part in adaptive plant evolution. This Review describes the kinds of changes that transposable elements can cause, discusses evidence that those changes have contributed to plant evolution and suggests future strategies for determining the extent to which these changes have in fact contributed to plant adaptation and evolution. Recent advances in genomics and phenomics for a range of plant species, particularly crops, have begun to allow the systematic assessment of these questions.
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Affiliation(s)
- Damon Lisch
- Department of Plant and Microbial Biology, UC Berkeley, Berkeley, California 94720, USA.
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Kim K, Choi D, Kim SM, Kwak DY, Choi J, Lee S, Lee BC, Hwang D, Hwang I. A systems approach for identifying resistance factors to Rice stripe virus. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:534-545. [PMID: 22217248 DOI: 10.1094/mpmi-11-11-0282] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Rice stripe virus (RSV) causes disease that can severely affect the productivity of rice (Oryza sativa). Several RSV-resistant cultivars have been developed. However, host factors conferring RSV resistance in these cultivars are still elusive. Here, we present a systems approach for identifying potential rice resistance factors. We developed two near-isogenic lines (NIL), RSV-resistant NIL22 and RSV-susceptible NIL37, and performed gene expression profiling of the two lines in RSV-infected and RSV-uninfected conditions. We identified 237 differentially expressed genes (DEG) between NIL22 and NIL37. By integrating with known quantitative trait loci (QTL), we selected 11 DEG located within the RSV resistance QTL as RSV resistance factor candidates. Furthermore, we identified 417 DEG between RSV-infected and RSV-uninfected conditions. Using an interaction network-based method, we selected 20 DEG highly interacting with the two sets of DEG as RSV resistance factor candidates. Among the 31 candidates, we selected the final set of 21 potential RSV resistance factors whose differential expression was confirmed in the independent samples using real-time reverse-transcription polymerase chain reaction. Finally, we reconstructed a network model delineating potential association of the 21 selected factors with resistance-related processes. In summary, our approach, based on gene expression profiling, revealed potential host resistance factors and a network model describing their relationships with resistance-related processes, which can be further validated in detailed experiments.
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Affiliation(s)
- Kangmin Kim
- Department of Life Sciences, POSTECH, Pohang, Republic of Korea
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