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Herridge RP, Dolata J, Migliori V, de Santis Alves C, Borges F, Schorn AJ, van Ex F, Lin A, Bajczyk M, Parent JS, Leonardi T, Hendrick A, Kouzarides T, Martienssen RA. Pseudouridine guides germline small RNA transport and epigenetic inheritance. Nat Struct Mol Biol 2024:10.1038/s41594-024-01392-6. [PMID: 39242979 DOI: 10.1038/s41594-024-01392-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Accepted: 08/15/2024] [Indexed: 09/09/2024]
Abstract
Developmental epigenetic modifications in plants and animals are mostly reset during gamete formation but some are inherited from the germline. Small RNAs guide these epigenetic modifications but how inherited small RNAs are distinguished in plants and animals is unknown. Pseudouridine (Ψ) is the most abundant RNA modification but has not been explored in small RNAs. Here, we develop assays to detect Ψ in short RNA sequences, demonstrating its presence in mouse and Arabidopsis microRNAs. Germline small RNAs, namely epigenetically activated small interfering RNAs (easiRNAs) in Arabidopsis pollen and Piwi-interacting RNAs in mouse testes, are enriched for Ψ. In pollen, pseudouridylated easiRNAs are transported to sperm cells from the vegetative nucleus, and PAUSED/HEN5 (PSD), the plant homolog of Exportin-t, interacts genetically with Ψ and is required for this transport. We further show that Exportin-t is required for the triploid block: small RNA dosage-dependent seed lethality that is epigenetically inherited from pollen. Thus, Ψ has a conserved role in marking inherited small RNAs in the germline.
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Affiliation(s)
- Rowan P Herridge
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Department of Biochemistry, University of Otago, Dunedin, New Zealand
| | - Jakub Dolata
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Valentina Migliori
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | | | - Filipe Borges
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- CNRS, INRA Versailles, Versailles, France
| | - Andrea J Schorn
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Frédéric van Ex
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Inari LLC, Ghent, Belgium
| | - Ann Lin
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Stanford University, Stanford, CA, USA
| | - Mateusz Bajczyk
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Jean-Sebastien Parent
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
- Agriculture Canada, Ottawa, Ontario, Canada
| | - Tommaso Leonardi
- Gurdon Institute, University of Cambridge, Cambridge, UK
- Center for Genomic Science of IIT@SEMM, Instituto Italiano di Tecnologia (IIT), Milan, Italy
| | - Alan Hendrick
- Storm Therapeutics, Ltd., Moneta Building (B280), Babraham Research Campus, Cambridge, UK
| | | | - Robert A Martienssen
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA.
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2
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Genschik P, Schiaffini M, Lechner E. Proteolytic control of the RNA silencing machinery. THE PLANT CELL 2024; 36:2997-3008. [PMID: 38456220 PMCID: PMC11371168 DOI: 10.1093/plcell/koae075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 12/22/2023] [Accepted: 01/11/2024] [Indexed: 03/09/2024]
Abstract
Studies in plants were often pioneering in the field of RNA silencing and revealed a broad range of small RNA (sRNA) categories. When associated with ARGONAUTE (AGO) proteins, sRNAs play important functions in development, genome integrity, stress responses, and antiviral immunity. Today, most of the protein factors required for the biogenesis of sRNA classes, their amplification through the production of double-stranded RNA, and their function in transcriptional and posttranscriptional regulation have been identified. Nevertheless, and despite the importance of RNA silencing, we still know very little about their posttranslational regulation. This is in stark contrast with studies in metazoans, where different modifications such as prolyl hydroxylation, phosphorylation, sumoylation, ubiquitylation, and others have been reported to alter the activity and stability of key factors, such as AGO proteins. Here, we review current knowledge of how key components of the RNA silencing machinery in plants are regulated during development and by microbial hijacking of endogenous proteases.
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Affiliation(s)
- Pascal Genschik
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, Strasbourg 67084, France
| | - Marlene Schiaffini
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, Strasbourg 67084, France
| | - Esther Lechner
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, Strasbourg 67084, France
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3
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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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Yue Z, Deng C, Zeng Y, Shang H, Wang S, Liu S, Liu H. Phyllostachys edulis argonaute genes function in the shoot architecture. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 345:112114. [PMID: 38735397 DOI: 10.1016/j.plantsci.2024.112114] [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: 01/17/2024] [Revised: 03/29/2024] [Accepted: 05/07/2024] [Indexed: 05/14/2024]
Abstract
Argonaute (AGO) proteins are the core components of the RNA-induced silencing complexes (RISC) in the cytoplasm and nucleus, and are necessary for the development of plant shoot meristem, which gives rise to the above-ground plant body. In this study, we identified 23 Phyllostachys edulis AGO genes (PhAGOs) that were distributed unequally on the 14 unmapped scaffolds. Gene collinearity and phylogeny analysis showed that the innovation of PhAGO genes was mainly due to dispersed duplication and whole-genome duplication, which resulted in the enlarged PhAGO family. PhAGO genes were expressed in a temporal-spatial expression pattern, and they encoded proteins differently localized in the cytoplasm and/or nucleus. Overexpression of the PhAGO2 and PhAGO4 genes increased the number of tillers or leaves in Oryza sativa and affected the shoot architecture of Arabidopsis thaliana. These results provided insight into the fact that PhAGO genes play important roles in plant development.
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Affiliation(s)
- Zhiqiang Yue
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, China
| | - Chu Deng
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, China
| | - Yuxue Zeng
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, China
| | - Hongna Shang
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, China
| | - Shuo Wang
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, China
| | - Shenkui Liu
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, China.
| | - Hua Liu
- State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, China.
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5
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Iwakawa HO. The clade-specific target recognition mechanisms of plant RISCs. Nucleic Acids Res 2024; 52:6662-6673. [PMID: 38621714 PMCID: PMC11194062 DOI: 10.1093/nar/gkae257] [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: 01/03/2024] [Revised: 03/04/2024] [Accepted: 04/01/2024] [Indexed: 04/17/2024] Open
Abstract
Eukaryotic Argonaut proteins (AGOs) assemble RNA-induced silencing complexes (RISCs) with guide RNAs that allow binding to complementary RNA sequences and subsequent silencing of target genes. The model plant Arabidopsis thaliana encodes 10 different AGOs, categorized into three distinct clades based on amino acid sequence similarity. While clade 1 and 2 RISCs are known for their roles in post-transcriptional gene silencing, and clade 3 RISCs are associated with transcriptional gene silencing in the nucleus, the specific mechanisms of how RISCs from each clade recognize their targets remain unclear. In this study, I conducted quantitative binding analyses between RISCs and target nucleic acids with mismatches at various positions, unveiling distinct target binding characteristics unique to each clade. Clade 1 and 2 RISCs require base pairing not only in the seed region but also in the 3' supplementary region for stable target RNA binding, with clade 1 exhibiting a higher stringency. Conversely, clade 3 RISCs tolerate dinucleotide mismatches beyond the seed region. Strikingly, they bind to DNA targets with an affinity equal to or surpassing that of RNA, like prokaryotic AGO complexes. These insights challenge existing views on plant RNA silencing and open avenues for exploring new functions of eukaryotic AGOs.
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Affiliation(s)
- Hiro-oki Iwakawa
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
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6
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Tovar-Aguilar A, Grimanelli D, Acosta-García G, Vielle-Calzada JP, Badillo-Corona JA, Durán-Figueroa N. The miRNA822 loaded by ARGONAUTE9 modulates the monosporic female gametogenesis in Arabidopsis thaliana. PLANT REPRODUCTION 2024; 37:243-258. [PMID: 38019279 DOI: 10.1007/s00497-023-00487-2] [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: 05/31/2023] [Accepted: 11/07/2023] [Indexed: 11/30/2023]
Abstract
KEY MESSAGE The miR822 together with of AGO9 protein, modulates monosporic development in Arabidopsis thaliana through the regulation of target genes encoding Cysteine/Histidine-Rich C1 domain proteins, revealing a new role of miRNAs in the control of megaspore formation in flowering plants. In the ovule of flowering plants, the establishment of the haploid generation occurs when a somatic cell differentiates into a megaspore mother cell (MMC) and initiates meiosis. As most flowering plants, Arabidopsis thaliana (Arabidopsis) undergoes a monosporic type of gametogenesis as three meiotically derived cells degenerate, and a single one-the functional megaspore (FM), divides mitotically to form the female gametophyte. The genetic basis and molecular mechanisms that control monosporic gametophyte development remain largely unknown. Here, we show that Arabidopsis plants carrying loss-of-function mutations in the miR822, give rise to extranumerary surviving megaspores that acquire a FM identity and divides without giving rise to differentiated female gametophytes. The overexpression of three miR822 putative target genes encoding cysteine/histidine-rich C1 (DC1) domain proteins, At5g02350, At5g02330 and At2g13900 results in defects equivalent to those found in mutant mir822 plants. The three miR822 targets genes are overexpressed in ago9 mutant ovules, suggesting that miR822 acts through an AGO9-dependent pathway to negatively regulate DC1 domain proteins and restricts the survival of meiotically derived cells to a single megaspore. Our results identify a mechanism mediated by the AGO9-miR822 complex that modulates monosporic female gametogenesis in Arabidopsis thaliana.
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Affiliation(s)
- Andrea Tovar-Aguilar
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología, Mexico City, Mexico
| | - Daniel Grimanelli
- Institut de Recherche pour le Développement, Plant Genome and Development Laboratory, UMR5096, 34394, Montpellier, France
| | - Gerardo Acosta-García
- Departamento de Bioquímica, Instituto Tecnológico de Celaya, Celaya, Guanajuato, Mexico
| | - Jean-Philippe Vielle-Calzada
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, CINVESTAV-IPN, Irapuato, Guanajuato, Mexico
| | | | - Noé Durán-Figueroa
- Instituto Politécnico Nacional, Unidad Profesional Interdisciplinaria de Biotecnología, Mexico City, Mexico.
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7
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Bradamante G, Nguyen VH, Incarbone M, Meir Z, Bente H, Donà M, Lettner N, Scheid OM, Gutzat R. Two ARGONAUTE proteins loaded with transposon-derived small RNAs are associated with the reproductive cell lineage in Arabidopsis. THE PLANT CELL 2024; 36:863-880. [PMID: 38060984 PMCID: PMC10980394 DOI: 10.1093/plcell/koad295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 11/23/2023] [Indexed: 04/01/2024]
Abstract
In sexually propagating organisms, genetic, and epigenetic mutations are evolutionarily relevant only if they occur in the germline and are hence transmitted to the next generation. In contrast to most animals, plants are considered to lack an early segregating germline, implying that somatic cells can contribute genetic information to progeny. Here we demonstrate that 2 ARGONAUTE proteins, AGO5 and AGO9, mark cells associated with sexual reproduction in Arabidopsis (Arabidopsis thaliana) throughout development. Both AGOs are loaded with dynamically changing small RNA populations derived from highly methylated, pericentromeric, long transposons. Sequencing of single stem cell nuclei revealed that many of these transposons are co-expressed within an AGO5/9 expression domain in the shoot apical meristem (SAM). Co-occurrence of transposon expression and specific ARGONAUTE (AGO) expression in the SAM is reminiscent of germline features in animals and supports the existence of an early segregating germline in plants. Our results open the path to investigating transposon biology and epigenome dynamics at cellular resolution in the SAM stem cell niche.
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Affiliation(s)
- Gabriele Bradamante
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Vu Hoang Nguyen
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Marco Incarbone
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Zohar Meir
- Faculty of Mathematics and Computer Science & Department of Plant and Environmental Sciences, Weizmann Institute of Science, 7610001 Rehovot, Israel
| | - Heinrich Bente
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Mattia Donà
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Nicole Lettner
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Ortrun Mittelsten Scheid
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
| | - Ruben Gutzat
- Austrian Academy of Sciences, Vienna Biocenter (VBC), Gregor Mendel Institute of Molecular Plant Biology, 1030 Vienna, Austria
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Čermák V, Kašpar T, Fischer L. SPT6L, a newly discovered ancestral component of the plant RNA-directed DNA methylation pathway. FRONTIERS IN PLANT SCIENCE 2024; 15:1372880. [PMID: 38576781 PMCID: PMC10991848 DOI: 10.3389/fpls.2024.1372880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Accepted: 02/20/2024] [Indexed: 04/06/2024]
Abstract
RNA-directed DNA methylation (RdDM) is driven by small RNAs (sRNAs) complementary to the nascent transcript of RNA polymerase V (Pol V). sRNAs associated with ARGONAUTE (AGO) proteins are tethered to Pol V mainly by the AGO-hook domain of its subunit NRPE1. We found, by in silico analyses, that Pol V strongly colocalizes on chromatin with another AGO-hook protein, SPT6-like (SPT6L), which is a known essential transcription elongation factor of Pol II. Our phylogenetic analysis revealed that SPT6L acquired its AGO-binding capacity already in the most basal streptophyte algae, even before the emergence of Pol V, suggesting that SPT6L might be a driving force behind the RdDM evolution. Since its emergence, SPT6L with the AGO-hook represents the only conserved SPT6 homolog in Viridiplantae, implying that the same protein is involved in both Pol II and Pol V complexes. To better understand the role of SPT6L in the Pol V complex, we characterized genomic loci where these two colocalize and uncovered that DNA methylation there is more dynamic, driven by higher levels of sRNAs often from non-canonical RdDM pathways and more dependent on chromatin modifying and remodeling proteins like MORC. Pol V loci with SPT6L are highly depleted in helitrons but enriched in gene promoters for which locally and temporally precise methylation is necessary. In view of these results, we discuss potential roles of multiple AGO-hook domains present in the Pol V complex and speculate that SPT6L mediates de novo methylation of naïve loci by interconnecting Pol II and Pol V activities.
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Affiliation(s)
- Vojtěch Čermák
- Laboratory of Plant Cell Biology and Biotechnology, Faculty of Science, Department of Experimental Plant Biology, Charles University, Prague, Czechia
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Miloro F, Kis A, Havelda Z, Dalmadi Á. Barley AGO4 proteins show overlapping functionality with distinct small RNA-binding properties in heterologous complementation. PLANT CELL REPORTS 2024; 43:96. [PMID: 38480545 PMCID: PMC10937801 DOI: 10.1007/s00299-024-03177-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 02/15/2024] [Indexed: 03/17/2024]
Abstract
KEY MESSAGE Barley AGO4 proteins complement expressional changes of epigenetically regulated genes in Arabidopsis ago4-3 mutant and show a distinct affinity for the 5' terminal nucleotide of small RNAs, demonstrating functional conservation and divergence. The function of Argonaute 4 (AGO4) in Arabidopsis thaliana has been extensively characterized; however, its role in monocots, which have large genomes abundantly supplemented with transposable elements (TEs), remains elusive. The study of barley AGO4 proteins can provide insights into the conserved aspects of RNA-directed DNA methylation (RdDM) and could also have further applications in the field of epigenetics or crop improvement. Bioinformatic analysis of RNA sequencing data identified two active AGO4 genes in barley, HvAGO4a and HvAGO4b. These genes function similar to AtAGO4 in an Arabidopsis heterologous complementation system, primarily binding to 24-nucleotide long small RNAs (sRNAs) and triggering methylation at specific target loci. Like AtAGO4, HvAGO4B exhibits a preference for binding sRNAs with 5' adenine residue, while also accepting 5' guanine, uracil, and cytosine residues. In contrast, HvAGO4A selectively binds only sRNAs with a 5' adenine residue. The diverse binding capacity of barley AGO4 proteins is reflected in TE-derived sRNAs and in their varying abundance. Both barley AGO4 proteins effectively restore the levels of extrachromosomal DNA and transcript abundancy of the heat-activated ONSEN retrotransposon to those observed in wild-type Arabidopsis plants. Our study provides insight into the distinct binding specificities and involvement in TE regulation of barley AGO4 proteins in Arabidopsis by heterologous complementation.
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Affiliation(s)
- Fabio Miloro
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Gödöllő, Hungary
| | - András Kis
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary
| | - Zoltán Havelda
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Gödöllő, Hungary
| | - Ágnes Dalmadi
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary.
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Gödöllő, Hungary.
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10
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Vaucheret H, Voinnet O. The plant siRNA landscape. THE PLANT CELL 2024; 36:246-275. [PMID: 37772967 PMCID: PMC10827316 DOI: 10.1093/plcell/koad253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 09/12/2023] [Accepted: 09/28/2023] [Indexed: 09/30/2023]
Abstract
Whereas micro (mi)RNAs are considered the clean, noble side of the small RNA world, small interfering (si)RNAs are often seen as a noisy set of molecules whose barbarian acronyms reflect a large diversity of often elusive origins and functions. Twenty-five years after their discovery in plants, however, new classes of siRNAs are still being identified, sometimes in discrete tissues or at particular developmental stages, making the plant siRNA world substantially more complex and subtle than originally anticipated. Focusing primarily on the model Arabidopsis, we review here the plant siRNA landscape, including transposable elements (TE)-derived siRNAs, a vast array of non-TE-derived endogenous siRNAs, as well as exogenous siRNAs produced in response to invading nucleic acids such as viruses or transgenes. We primarily emphasize the extraordinary sophistication and diversity of their biogenesis and, secondarily, the variety of their known or presumed functions, including via non-cell autonomous activities, in the sporophyte, gametophyte, and shortly after fertilization.
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Affiliation(s)
- Hervé Vaucheret
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Olivier Voinnet
- Department of Biology, Swiss Federal Institute of Technology (ETH-Zurich), 8092 Zürich, Switzerland
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11
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Chaudhary D, Jeena AS, Rohit, Gaur S, Raj R, Mishra S, Kajal, Gupta OP, Meena MR. Advances in RNA Interference for Plant Functional Genomics: Unveiling Traits, Mechanisms, and Future Directions. Appl Biochem Biotechnol 2024:10.1007/s12010-023-04850-x. [PMID: 38175411 DOI: 10.1007/s12010-023-04850-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/19/2023] [Indexed: 01/05/2024]
Abstract
RNA interference (RNAi) is a conserved molecular mechanism that plays a critical role in post-transcriptional gene silencing across diverse organisms. This review delves into the role of RNAi in plant functional genomics and its applications in crop improvement, highlighting its mechanistic insights and practical implications. The review begins with the foundational discovery of RNAi's mechanism, tracing its origins from petunias to its widespread presence in various organisms. Various classes of regulatory non-coding small RNAs, including siRNAs, miRNAs, and phasiRNAs, have been uncovered, expanding the scope of RNAi-mediated gene regulation beyond conventional understanding. These RNA classes participate in intricate post-transcriptional and epigenetic processes that influence gene expression. In the context of crop enhancement, RNAi has emerged as a powerful tool for understanding gene functions. It has proven effective in deciphering gene roles related to stress resistance, metabolic pathways, and more. Additionally, RNAi-based approaches hold promise for integrated pest management and sustainable agriculture, contributing to global efforts in food security. This review discusses RNAi's diverse applications, such as modifying plant architecture, extending shelf life, and enhancing nutritional content in crops. The challenges and future prospects of RNAi technology, including delivery methods and biosafety concerns, are also explored. The global landscape of RNAi research is highlighted, with significant contributions from regions such as China, Europe, and North America. In conclusion, RNAi remains a versatile and pivotal tool in modern plant research, offering novel avenues for understanding gene functions and improving crop traits. Its integration with other biotechnological approaches such as gene editing holds the potential to shape the future of agriculture and sustainable food production.
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Affiliation(s)
- Divya Chaudhary
- Department of Genetics and Plant Breeding, College of Agriculture, G B Pant University of Agriculture and Technology, Pantnagar, 263145, Uttarakhand, India
| | - Anand Singh Jeena
- Department of Genetics and Plant Breeding, College of Agriculture, G B Pant University of Agriculture and Technology, Pantnagar, 263145, Uttarakhand, India.
| | - Rohit
- Department of Genetics and Plant Breeding, College of Agriculture, G B Pant University of Agriculture and Technology, Pantnagar, 263145, Uttarakhand, India
| | - Sonali Gaur
- Department of Genetics and Plant Breeding, College of Agriculture, G B Pant University of Agriculture and Technology, Pantnagar, 263145, Uttarakhand, India
| | - Rishi Raj
- ICAR- Sugarcane Breeding Institute-Regional Centre, Karnal, 132001, Haryana, India
| | | | - Kajal
- Department of Biotechnology, Chandigarh University, Chandigarh, 140143, India
| | - Om Prakash Gupta
- ICAR-Indian Institute of Wheat and Barley Research, Karnal, 132001, Haryana, India.
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12
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Nakanishi K. When Argonaute takes out the ribonuclease sword. J Biol Chem 2024; 300:105499. [PMID: 38029964 PMCID: PMC10772731 DOI: 10.1016/j.jbc.2023.105499] [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: 07/10/2023] [Revised: 11/11/2023] [Accepted: 11/15/2023] [Indexed: 12/01/2023] Open
Abstract
Argonaute (AGO) proteins in all three domains of life form ribonucleoprotein or deoxyribonucleoprotein complexes by loading a guide RNA or DNA, respectively. Since all AGOs retain a PIWI domain that takes an RNase H fold, the ancestor was likely an endoribonuclease (i.e., a slicer). In animals, most miRNA-mediated gene silencing occurs slicer independently. However, the slicer activity of AGO is indispensable in specific events, such as development and differentiation, which are critical for vertebrates and thus cannot be replaced by the slicer-independent regulation. This review highlights the distinctions in catalytic activation mechanisms among slicing-competent AGOs, shedding light on the roles of two metal ions in target recognition and cleavage. The precision of the target specificity by the RNA-induced silencing complexes is reevaluated and redefined. The possible coevolutionary relationship between slicer-independent gene regulation and AGO-binding protein, GW182, is also explored. These discussions reveal that numerous captivating questions remain unanswered regarding the timing and manner in which AGOs employ their slicing activity.
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Affiliation(s)
- Kotaro Nakanishi
- Department of Chemistry and Biochemistry, The Ohio State University, Columbus, Ohio, USA; Center for RNA Biology, The Ohio State University, Columbus, Ohio, USA.
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13
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Mu J, Zhou X, Xing Y, Zhang M, Zhang J, Li F, Ge J, Zhao M, Liu L, Gong D, Geng T. Thyroid hormone-responsive protein mediates the response of chicken liver to fasting mainly through the cytokine-cytokine receptor interaction pathway. Br Poult Sci 2023; 64:733-744. [PMID: 37565565 DOI: 10.1080/00071668.2023.2246135] [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: 04/19/2023] [Revised: 07/02/2023] [Accepted: 07/10/2023] [Indexed: 08/12/2023]
Abstract
1. The objective of this study was to explore the mediating role of thyroid hormone-responsive protein (THRSP) in the response of chicken liver to fasting.2. A batch of 7-d-old chicks with similar body weights were randomly divided into the control group and the fasting group (n = 10). The control group was fed ad libitum, while the test group fasted for 24 h. The liver and pectoral muscle tissues were collected. Chicken primary hepatocytes or myocytes were treated with different concentrations of thyroxine, glucose, insulin, oleic acid and palmitic acid, separately. Chicken primary hepatocytes were transfected with THRSP overexpression vector vs. empty vector, and the cells were used for transcriptome analysis. The mRNA expression of THRSP and other genes was determined by quantitative PCR.3. The expression of THRSP in chicken liver and pectoral muscle tissues was significantly inhibited by fasting (P < 0.05). In chicken primary hepatocytes, the expression of THRSP was significantly induced by thyroxine (0.25, 0.5, 1 mmol/l), glucose (50, 100 mmol/l), and insulin (20 nmol/l), and was significantly inhibited by palmitic acid (0.125, 0.25 mmol/l). In the myocytes, expression of THRSP was significantly induced by thyroxine (0.25, 0.5, 1 mmol/l), glucose (50 mmol/l) and oleic acid (0.125, 0.25 mmol/l), was significantly inhibited by insulin (5 nmol/l) and was not significantly affected by palmitic acid.4. Transcriptome analysis showed that overexpression of THRSP significantly affected the expression of 1411 DEGs, of which 1007 were up-regulated and 404 were down-regulated. The GO term and KEGG pathway enrichment analyses showed that these DEGs were mainly enriched in the interaction between cytokine and cytokine receptor and its regulation and signal transduction, cell growth and apoptosis and its regulation, immune response and retinol metabolism.5. In conclusion, the THRSP gene mediates biological effects of fasting by influencing the expressional regulation of the genes related to biological processes such as cytokine-cytokine receptor interaction, cell growth and apoptosis, immune response, retinol metabolism, including TGM2, HSD17B2, RUNX3, IRF1, ANKRD6, UPP2, IKBKE, and PYCR1 genes, in chicken liver.
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Affiliation(s)
- J Mu
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - X Zhou
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - Y Xing
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - M Zhang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - J Zhang
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - F Li
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - J Ge
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - M Zhao
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - L Liu
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
| | - D Gong
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China
| | - T Geng
- College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu, China
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education of China, Yangzhou University, Yangzhou, Jiangsu, China
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14
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Fujimoto Y, Iwakawa HO. Mechanisms that regulate the production of secondary siRNAs in plants. J Biochem 2023; 174:491-499. [PMID: 37757447 DOI: 10.1093/jb/mvad071] [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: 06/30/2023] [Revised: 08/28/2023] [Accepted: 09/21/2023] [Indexed: 09/29/2023] Open
Abstract
Many organisms produce secondary small interfering RNAs (siRNAs) that are triggered by primary small RNAs to regulate various biological processes. Plants have evolved several types of secondary siRNA biogenesis pathways that play important roles in development, stress responses and defense against viruses and transposons. The critical step of these pathways is the production of double-stranded RNAs by RNA-dependent RNA polymerases. This step is normally tightly regulated, but when its control is released, secondary siRNA production is initiated. In this article, we will review the recent advances in secondary siRNA production triggered by microRNAs encoded in the genome and siRNAs derived from invasive nucleic acids. In particular, we will focus on the factors, events, and RNA/DNA elements that promote or inhibit the early steps of secondary siRNA biogenesis.
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Affiliation(s)
- Yuji Fujimoto
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
| | - Hiro-Oki Iwakawa
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
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15
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Liang C, Wang X, He H, Xu C, Cui J. Beyond Loading: Functions of Plant ARGONAUTE Proteins. Int J Mol Sci 2023; 24:16054. [PMID: 38003244 PMCID: PMC10671604 DOI: 10.3390/ijms242216054] [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: 09/25/2023] [Revised: 10/31/2023] [Accepted: 11/04/2023] [Indexed: 11/26/2023] Open
Abstract
ARGONAUTE (AGO) proteins are key components of the RNA-induced silencing complex (RISC) that mediates gene silencing in eukaryotes. Small-RNA (sRNA) cargoes are selectively loaded into different members of the AGO protein family and then target complementary sequences to in-duce transcriptional repression, mRNA cleavage, or translation inhibition. Previous reviews have mainly focused on the traditional roles of AGOs in specific biological processes or on the molecular mechanisms of sRNA sorting. In this review, we summarize the biological significance of canonical sRNA loading, including the balance among distinct sRNA pathways, cross-regulation of different RISC activities during plant development and defense, and, especially, the emerging roles of AGOs in sRNA movement. We also discuss recent advances in novel non-canonical functions of plant AGOs. Perspectives for future functional studies of this evolutionarily conserved eukaryotic protein family will facilitate a more comprehensive understanding of the multi-faceted AGO proteins.
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Affiliation(s)
| | | | | | | | - Jie Cui
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (C.L.); (X.W.); (H.H.); (C.X.)
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16
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Herridge RP, Dolata J, Migliori V, de Santis Alves C, Borges F, Schorn AJ, Van Ex F, Parent JS, Lin A, Bajczyk M, Leonardi T, Hendrick A, Kouzarides T, Martienssen RA. Pseudouridine guides germline small RNA transport and epigenetic inheritance. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.27.542553. [PMID: 37398006 PMCID: PMC10312437 DOI: 10.1101/2023.05.27.542553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Epigenetic modifications that arise during plant and animal development, such as DNA and histone modification, are mostly reset during gamete formation, but some are inherited from the germline including those marking imprinted genes1. Small RNAs guide these epigenetic modifications, and some are also inherited by the next generation2,3. In C. elegans, these inherited small RNAs have poly (UG) tails4, but how inherited small RNAs are distinguished in other animals and plants is unknown. Pseudouridine (Ψ) is the most abundant RNA modification but has not been explored in small RNAs. Here, we develop novel assays to detect Ψ in short RNA sequences, demonstrating its presence in mouse and Arabidopsis microRNAs and their precursors. We also detect substantial enrichment in germline small RNAs, namely epigenetically activated siRNAs (easiRNAs) in Arabidopsis pollen, and piwi-interacting piRNAs in mouse testis. In pollen, pseudouridylated easiRNAs are localized to sperm cells, and we found that PAUSED/HEN5 (PSD), the plant homolog of Exportin-t, interacts genetically with Ψ and is required for transport of easiRNAs into sperm cells from the vegetative nucleus. We further show that Exportin-t is required for the triploid block: chromosome dosage-dependent seed lethality that is epigenetically inherited from pollen. Thus, Ψ has a conserved role in marking inherited small RNAs in the germline.
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Affiliation(s)
- Rowan P Herridge
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Jakub Dolata
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Valentina Migliori
- The Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | | | - Filipe Borges
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Andrea J Schorn
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Frédéric Van Ex
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Jean-Sebastien Parent
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Ann Lin
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
| | - Mateusz Bajczyk
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Tommaso Leonardi
- The Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
- Center for Genomic Science of IIT@SEMM, Instituto Italiano di Tecnologia (IIT), 20139 Milan, Italy
| | - Alan Hendrick
- Storm Therapeutics, Ltd., Moneta Building (B280), Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Tony Kouzarides
- The Gurdon Institute, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Robert A Martienssen
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, 11724, USA
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17
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Bonnet DMV, Tirot L, Grob S, Jullien PE. Methylome Response to Proteasome Inhibition by Pseudomonas syringae Virulence Factor Syringolin A. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2023; 36:693-704. [PMID: 37414416 DOI: 10.1094/mpmi-06-23-0080-r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/08/2023]
Abstract
DNA methylation is an important epigenetic mark required for proper gene expression and silencing of transposable elements. DNA methylation patterns can be modified by environmental factors such as pathogen infection, in which modification of DNA methylation can be associated with plant resistance. To counter the plant defense pathways, pathogens produce effector molecules, several of which act as proteasome inhibitors. Here, we investigated the effect of proteasome inhibition by the bacterial virulence factor syringolin A (SylA) on genome-wide DNA methylation. We show that SylA treatment results in an increase of DNA methylation at centromeric and pericentromeric regions of Arabidopsis chromosomes. We identify several CHH differentially methylated regions (DMRs) that are enriched in the proximity of transcriptional start sites. SylA treatment does not result in significant changes in small RNA composition. However, significant changes in genome transcriptional activity can be observed, including a strong upregulation of resistance genes that are located on chromosomal arms. We hypothesize that DNA methylation changes could be linked to the upregulation of some atypical members of the de novo DNA methylation pathway, namely AGO3, AGO9, and DRM1. Our data suggests that modification of genome-wide DNA methylation resulting from an inhibition of the proteasome by bacterial effectors could be part of an epi-genomic arms race against pathogens. [Formula: see text] Copyright © 2023 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
| | - Louis Tirot
- Institute of Plant Sciences, University of Bern, Bern, Switzerland
| | - Stefan Grob
- Department of Plant and Microbial Biology, University of Zurich and Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
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18
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Mishra S, Sharma P, Singh R, Ahlawat OP, Singh G. Genome-wide identification of DCL, AGO, and RDR gene families in wheat ( Triticum aestivum L.) and their expression analysis in response to heat stress. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2023; 29:1525-1541. [PMID: 38076771 PMCID: PMC10709266 DOI: 10.1007/s12298-023-01362-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 09/12/2023] [Accepted: 09/14/2023] [Indexed: 10/04/2024]
Abstract
Key components of the RNA interference (RNAi) pathway include the Dicer-like (DCL), Argonaute (AGO), and RNA-dependent RNA polymerase (RDR) gene families. While these components have been studied in various plant species, their functional validation in wheat remains unexplored particularly under heat stress. In this study, a comprehensive genome-wide analysis to identify, and characterize DCL, AGO, and RDR genes in wheat and their expression patterns was carried out. Using phylogenetic analysis with orthologous genes from Arabidopsis and rice, we identified a total of 82 AGO, 31 DCL, and 31 RDR genes distributed across the 21 chromosomes of wheat. To understand the regulatory network, a network analysis of miRNAs that target RNA-silencing genes was performed. Our analysis revealed that 13 miRNAs target AGO genes, 8 miRNAs target DCL genes, and 10 miRNAs target RDR genes at different sites, respectively. Additionally, promoter analysis of the RNA-silencing genes was done and identified the presence of 132 cis-elements responsive to stress and phytohormones. To examine their expression patterns, we performed RNA-seq analysis in the flag leaf samples of wheat exposed to both normal and heat stress conditions. To understand the regulation of RNA silencing, we experimentally analysed the transcriptional changes in response to gradient heat stress treatments. Our results showed constitutive expression of the AGO1, AGO9, and DCL2 gene families, indicating their importance in the overall biological processes of wheat. Notably, RDR1, known to be involved in small interfering RNA (siRNA) biogenesis, exhibited higher expression levels in wheat leaf tissues. These findings suggest that these genes may play a role in responses to stress in wheat, highlighting their significance in adapting to environmental challenges. Overall, our study provides additional knowledge to understand the mechanisms underlying heat stress responses and emphasizes the essential roles of these gene families in wheat. Supplementary Information The online version contains supplementary material available at 10.1007/s12298-023-01362-0.
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Affiliation(s)
- Shefali Mishra
- ICAR-Indian Institute of Wheat and Barley Research, Agrasain Marg, PO BOX-158, Karnal, Haryana 132 001 India
| | - Pradeep Sharma
- ICAR-Indian Institute of Wheat and Barley Research, Agrasain Marg, PO BOX-158, Karnal, Haryana 132 001 India
| | - Rajender Singh
- ICAR-Indian Institute of Wheat and Barley Research, Agrasain Marg, PO BOX-158, Karnal, Haryana 132 001 India
| | - Om Parkash Ahlawat
- ICAR-Indian Institute of Wheat and Barley Research, Agrasain Marg, PO BOX-158, Karnal, Haryana 132 001 India
| | - Gyanendra Singh
- ICAR-Indian Institute of Wheat and Barley Research, Agrasain Marg, PO BOX-158, Karnal, Haryana 132 001 India
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19
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Devers EA, Brosnan CA, Sarazin A, Schott G, Lim P, Lehesranta S, Helariutta Y, Voinnet O. In planta dynamics, transport biases, and endogenous functions of mobile siRNAs in Arabidopsis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2023; 115:1377-1393. [PMID: 37243897 DOI: 10.1111/tpj.16327] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 05/09/2023] [Accepted: 05/18/2023] [Indexed: 05/29/2023]
Abstract
In RNA interference (RNAi), small interfering RNAs (siRNAs) produced from double-stranded RNA guide ARGONAUTE (AGO) proteins to silence sequence-complementary RNA/DNA. RNAi can propagate locally and systemically in plants, but despite recent advances in our understanding of the underlying mechanisms, basic questions remain unaddressed. For instance, RNAi is inferred to diffuse through plasmodesmata (PDs), yet how its dynamics in planta compares with that of established symplastic diffusion markers remains unknown. Also is why select siRNA species, or size classes thereof, are apparently recovered in RNAi recipient tissues, yet only under some experimental settings. Shootward movement of endogenous RNAi in micro-grafted Arabidopsis is also yet to be achieved, while potential endogenous functions of mobile RNAi remain scarcely documented. Here, we show (i) that temporal, localized PD occlusion in source leaves' companion cells (CCs) suffices to abrogate all systemic manifestations of CC-activated mobile transgene silencing, including in sink leaves; (ii) that the presence or absence of specific AGOs in incipient/traversed/recipient tissues likely explains the apparent siRNA length selectivity observed upon vascular movement; (iii) that stress enhancement allows endo-siRNAs of a single inverted repeat (IR) locus to translocate against the shoot-to-root phloem flow; and (iv) that mobile endo-siRNAs generated from this locus have the potential to regulate hundreds of transcripts. Our results close important knowledge gaps, rationalize previously noted inconsistencies between mobile RNAi settings, and provide a framework for mobile endo-siRNA research.
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Affiliation(s)
- Emanuel A Devers
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätsstrasse 2, 8092, Zürich, Switzerland
| | - Christopher A Brosnan
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätsstrasse 2, 8092, Zürich, Switzerland
| | - Alexis Sarazin
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätsstrasse 2, 8092, Zürich, Switzerland
| | - Gregory Schott
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätsstrasse 2, 8092, Zürich, Switzerland
| | - Peiqi Lim
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätsstrasse 2, 8092, Zürich, Switzerland
| | - Satu Lehesranta
- Institute of Biotechnology, University of Helsinki, PO Box 65, Helsinki, FIN-00014, Finland
| | - Yrjö Helariutta
- Institute of Biotechnology, University of Helsinki, PO Box 65, Helsinki, FIN-00014, Finland
- Sainsbury Laboratory, University of Cambridge, Bateman Street, Cambridge, CB2 1LR, UK
| | - Olivier Voinnet
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätsstrasse 2, 8092, Zürich, Switzerland
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20
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Bélanger S, Zhan J, Meyers BC. Phylogenetic analyses of seven protein families refine the evolution of small RNA pathways in green plants. PLANT PHYSIOLOGY 2023; 192:1183-1203. [PMID: 36869858 PMCID: PMC10231463 DOI: 10.1093/plphys/kiad141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Revised: 02/14/2023] [Accepted: 02/15/2023] [Indexed: 06/01/2023]
Abstract
Several protein families participate in the biogenesis and function of small RNAs (sRNAs) in plants. Those with primary roles include Dicer-like (DCL), RNA-dependent RNA polymerase (RDR), and Argonaute (AGO) proteins. Protein families such as double-stranded RNA-binding (DRB), SERRATE (SE), and SUPPRESSION OF SILENCING 3 (SGS3) act as partners of DCL or RDR proteins. Here, we present curated annotations and phylogenetic analyses of seven sRNA pathway protein families performed on 196 species in the Viridiplantae (aka green plants) lineage. Our results suggest that the RDR3 proteins emerged earlier than RDR1/2/6. RDR6 is found in filamentous green algae and all land plants, suggesting that the evolution of RDR6 proteins coincides with the evolution of phased small interfering RNAs (siRNAs). We traced the origin of the 24-nt reproductive phased siRNA-associated DCL5 protein back to the American sweet flag (Acorus americanus), the earliest diverged, extant monocot species. Our analyses of AGOs identified multiple duplication events of AGO genes that were lost, retained, or further duplicated in subgroups, indicating that the evolution of AGOs is complex in monocots. The results also refine the evolution of several clades of AGO proteins, such as AGO4, AGO6, AGO17, and AGO18. Analyses of nuclear localization signal sequences and catalytic triads of AGO proteins shed light on the regulatory roles of diverse AGOs. Collectively, this work generates a curated and evolutionarily coherent annotation for gene families involved in plant sRNA biogenesis/function and provides insights into the evolution of major sRNA pathways.
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Affiliation(s)
| | - Junpeng Zhan
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St. Louis, MO 63132, USA
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
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21
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Li Y, Kim EJ, Voshall A, Moriyama EN, Cerutti H. Small RNAs >26 nt in length associate with AGO1 and are upregulated by nutrient deprivation in the alga Chlamydomonas. THE PLANT CELL 2023; 35:1868-1887. [PMID: 36945744 DOI: 10.1093/plcell/koad093] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 02/14/2023] [Accepted: 02/17/2023] [Indexed: 05/30/2023]
Abstract
Small RNAs (sRNAs) associate with ARGONAUTE (AGO) proteins forming effector complexes with key roles in gene regulation and defense responses against molecular parasites. In multicellular eukaryotes, extensive duplication and diversification of RNA interference (RNAi) components have resulted in intricate pathways for epigenetic control of gene expression. The unicellular alga Chlamydomonas reinhardtii also has a complex RNAi machinery, including 3 AGOs and 3 DICER-like proteins. However, little is known about the biogenesis and function of most endogenous sRNAs. We demonstrate here that Chlamydomonas contains uncommonly long (>26 nt) sRNAs that associate preferentially with AGO1. Somewhat reminiscent of animal PIWI-interacting RNAs, these >26 nt sRNAs are derived from moderately repetitive genomic clusters and their biogenesis is DICER-independent. Interestingly, the sequences generating these >26-nt sRNAs have been conserved and amplified in several Chlamydomonas species. Moreover, expression of these longer sRNAs increases substantially under nitrogen or sulfur deprivation, concurrently with the downregulation of predicted target transcripts. We hypothesize that the transposon-like sequences from which >26-nt sRNAs are produced might have been ancestrally targeted for silencing by the RNAi machinery but, during evolution, certain sRNAs might have fortuitously acquired endogenous target genes and become integrated into gene regulatory networks.
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Affiliation(s)
- Yingshan Li
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska-Lincoln, Nebraska-Lincoln, NE 68588-0666, USA
| | - Eun-Jeong Kim
- Department of Life Science, Chung-Ang University, Seoul 06974, Korea
| | - Adam Voshall
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska-Lincoln, Nebraska-Lincoln, NE 68588-0666, USA
- Division of Genetics and Genomics, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Etsuko N Moriyama
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska-Lincoln, Nebraska-Lincoln, NE 68588-0666, USA
| | - Heriberto Cerutti
- School of Biological Sciences and Center for Plant Science Innovation, University of Nebraska-Lincoln, Nebraska-Lincoln, NE 68588-0666, USA
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22
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Ortiz-Vasquez Q, León-Martínez G, Barragán-Rosillo C, González-Orozco E, Deans S, Aldridge B, Vickers M, Feng X, Vielle-Calzada JP. Genomic methylation patterns in pre-meiotic gynoecia of wild-type and RdDM mutants of Arabidopsis. FRONTIERS IN PLANT SCIENCE 2023; 14:1123211. [PMID: 36993852 PMCID: PMC10040562 DOI: 10.3389/fpls.2023.1123211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/02/2023] [Indexed: 06/19/2023]
Abstract
INTRODUCTION Although DNA methylation patterns are generally considered to be faithfully inherited in Arabidopsis thaliana (Arabidopsis), there is evidence of reprogramming during both male and female gametogenesis. The gynoecium is the floral reproductive organ from which the ovules develop and generate meiotically derived cells that give rise to the female gametophyte. It is not known whether the gynoecium can condition genomic methylation in the ovule or the developing female gametophyte. METHODS We performed whole genome bisulfite sequencing to characterize the methylation patterns that prevail in the genomic DNA of pre-meiotic gynoecia of wild-type and three mutants defective in genes of the RNA-directed DNA methylation pathway (RdDM): ARGONAUTE4 (AGO4), ARGONAUTE9 (AGO9), and RNA-DEPENDENT RNA POLYMERASE6 (RDR6). RESULTS By globally analyzing transposable elements (TEs) and genes located across the Arabidopsis genome, we show that DNA methylation levels are similar to those of gametophytic cells rather than those of sporophytic organs such as seedlings and rosette leaves. We show that none of the mutations completely abolishes RdDM, suggesting strong redundancy within the methylation pathways. Among all, ago4 mutation has the strongest effect on RdDM, causing more CHH hypomethylation than ago9 and rdr6. We identify 22 genes whose DNA methylation is significantly reduced in ago4, ago9 and rdr6 mutants, revealing potential targets regulated by the RdDM pathway in premeiotic gyneocia. DISCUSSION Our results indicate that drastic changes in methylation levels in all three contexts occur in female reproductive organs at the sporophytic level, prior to the alternation of generations within the ovule primordium, offering a possibility to start identifying the function of specific genes acting in the establishment of the female gametophytic phase of the Arabidopsis life cycle.
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Affiliation(s)
- Quetzely Ortiz-Vasquez
- Grupo de Desarrollo Reproductivo y Apomixis, Unidad de Genómica Avanzada Laboratorio Nacional de Genómica para la Biodiversidad, CINVESTAV, Irapuato, Guanajuato, Mexico
| | - Gloria León-Martínez
- Grupo de Desarrollo Reproductivo y Apomixis, Unidad de Genómica Avanzada Laboratorio Nacional de Genómica para la Biodiversidad, CINVESTAV, Irapuato, Guanajuato, Mexico
| | - Carlos Barragán-Rosillo
- Grupo de Desarrollo Reproductivo y Apomixis, Unidad de Genómica Avanzada Laboratorio Nacional de Genómica para la Biodiversidad, CINVESTAV, Irapuato, Guanajuato, Mexico
| | - Eduardo González-Orozco
- Grupo de Desarrollo Reproductivo y Apomixis, Unidad de Genómica Avanzada Laboratorio Nacional de Genómica para la Biodiversidad, CINVESTAV, Irapuato, Guanajuato, Mexico
| | - Samuel Deans
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Billy Aldridge
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Martin Vickers
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Xiaoqi Feng
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, United Kingdom
| | - Jean-Philippe Vielle-Calzada
- Grupo de Desarrollo Reproductivo y Apomixis, Unidad de Genómica Avanzada Laboratorio Nacional de Genómica para la Biodiversidad, CINVESTAV, Irapuato, Guanajuato, Mexico
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23
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Yun S, Zhang X. Genome-wide identification, characterization and expression analysis of AGO, DCL, and RDR families in Chenopodium quinoa. Sci Rep 2023; 13:3647. [PMID: 36871121 PMCID: PMC9985633 DOI: 10.1038/s41598-023-30827-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 03/02/2023] [Indexed: 03/06/2023] Open
Abstract
RNA interference is a highly conserved mechanism wherein several types of non-coding small RNAs regulate gene expression at the transcriptional or post-transcriptional level, modulating plant growth, development, antiviral defence, and stress responses. Argonaute (AGO), DCL (Dicer-like), and RNA-dependent RNA polymerase (RDR) are key proteins in this process. Here, these three protein families were identified in Chenopodium quinoa. Further, their phylogenetic relationships with Arabidopsis, their domains, three-dimensional structure modelling, subcellular localization, and functional annotation and expression were analysed. Whole-genome sequence analysis predicted 21 CqAGO, eight CqDCL, and 11 CqRDR genes in quinoa. All three protein families clustered into phylogenetic clades corresponding to those of Arabidopsis, including three AGO clades, four DCL clades, and four RDR clades, suggesting evolutionary conservation. Domain and protein structure analyses of the three gene families showed almost complete homogeneity among members of the same group. Gene ontology annotation revealed that the predicted gene families might be directly involved in RNAi and other important pathways. Largely, these gene families showed significant tissue-specific expression patterns, RNA-sequencing (RNA-seq) data revealed that 20 CqAGO, seven CqDCL, and ten CqRDR genes tended to have preferential expression in inflorescences. Most of them being downregulated in response to drought, cold, salt and low phosphate stress. To our knowledge, this is the first study to elucidate these key protein families involved in the RNAi pathway in quinoa, which are significant for understanding the mechanisms underlying stress responses in this plant.
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Affiliation(s)
- Shiyu Yun
- Institute of Industrial Crops, Shanxi Agricultural University, Taiyuan, 030031, China
| | - Xin Zhang
- Institute of Industrial Crops, Shanxi Agricultural University, Taiyuan, 030031, China.
- State Key Laboratory of Sustainable Dryland Agriculture, Shanxi Agricultural University, Taiyuan, 030031, China.
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Wang F, Huang HY, Huang J, Singh J, Pikaard CS. Enzymatic reactions of AGO4 in RNA-directed DNA methylation: siRNA duplex loading, passenger strand elimination, target RNA slicing, and sliced target retention. Genes Dev 2023; 37:103-118. [PMID: 36746605 PMCID: PMC10069450 DOI: 10.1101/gad.350240.122] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 01/13/2023] [Indexed: 02/08/2023]
Abstract
RNA-directed DNA methylation in plants is guided by 24-nt siRNAs generated in parallel with 23-nt RNAs of unknown function. We show that 23-nt RNAs function as passenger strands during 24-nt siRNA incorporation into AGO4. The 23-nt RNAs are then sliced into 11- and 12-nt fragments, with 12-nt fragments remaining associated with AGO4. Slicing recapitulated with recombinant AGO4 and synthetic RNAs reveals that siRNAs of 21-24 nt, with any 5'-terminal nucleotide, can guide slicing, with sliced RNAs then retained by AGO4. In vivo, RdDM target locus RNAs that copurify with AGO4 also display a sequence signature of slicing. Comparing plants expressing slicing-competent versus slicing-defective AGO4 shows that slicing elevates cytosine methylation levels at virtually all RdDM loci. We propose that siRNA passenger strand elimination and AGO4 tethering to sliced target RNAs are distinct modes by which AGO4 slicing enhances RNA-directed DNA methylation.
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Affiliation(s)
- Feng Wang
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, USA
- Howard Hughes Medical Institute, Indiana University, Bloomington, Indiana 47405, USA
| | - Hsiao-Yun Huang
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - Jie Huang
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - Jasleen Singh
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, USA
| | - Craig S Pikaard
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA;
- Department of Molecular and Cellular Biochemistry, Indiana University, Bloomington, Indiana 47405, USA
- Howard Hughes Medical Institute, Indiana University, Bloomington, Indiana 47405, USA
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25
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Edwards SA, Slotkin RK. Broken up but still living together: how ARGONAUTE's retention of cleaved fragments explains its role during chromatin modification. Genes Dev 2023; 37:69-71. [PMID: 36754778 PMCID: PMC10069453 DOI: 10.1101/gad.350424.123] [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] [Indexed: 02/10/2023]
Abstract
Throughout the eukaryotic kingdoms, small RNAs direct chromatin modification. ARGONAUTE proteins sit at the nexus of this process, linking the small RNA information to the programming of chromatin. ARGONAUTE proteins physically incorporate the small RNAs as guides to target specific regions of the genome. In this issue of Genes & Development, Wang and colleagues (pp. 103-118) add substantial new detail to the processes of ARGONAUTE RNA loading, preference, cleavage, and retention, which together accomplish RNA-directed chromatin modification. They show that after catalytic cleavage by the plant ARGONAUTE protein AGO4, the cleaved fragment remains bound. This happens during two distinct RNA cleavage reactions performed by AGO4: first for a passenger RNA strand of the siRNA duplex, and second for a nascent transcript at the target DNA locus. Cleaved fragment retention of the nascent transcript explains how the protein complex accumulates to high levels at the target locus, amplifying chromatin modification.
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Affiliation(s)
- Seth A Edwards
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132, USA
- Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA
| | - R Keith Slotkin
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132, USA;
- Division of Biological Sciences, University of Missouri, Columbia, Missouri 65211, USA
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26
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Wu X, Liu H, Lian B, Jiang X, Chen C, Tang T, Ding X, Hu J, Zhao S, Zhang S, Wu J. Genome-wide analysis of epigenetic and transcriptional changes in the pathogenesis of RGSV in rice. FRONTIERS IN PLANT SCIENCE 2023; 13:1090794. [PMID: 36714706 PMCID: PMC9874293 DOI: 10.3389/fpls.2022.1090794] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2022] [Accepted: 12/19/2022] [Indexed: 06/18/2023]
Abstract
Rice grassy stunt virus (RGSV), a typical negative single-stranded RNA virus, invades rice and generates several disease signs, including dwarfing, tillering, and sterility. Previous research has revealed that RGSV-encoded proteins can force the host's ubiquitin-proteasome system to utilize them for viral pathogenesis. However, most of the studies were limited to a single omics level and lacked multidimensional data collection and correlation analysis on the mechanisms of RGSV-rice interactions. Here, we performed a comprehensive association analysis of genome-wide methylation sequencing, transcriptome sequencing, and histone H3K9me3 modification in RGSV-infested as well as non-infested rice leaves, and the levels of all three cytosine contexts (CG, CHG and CHH) were found to be slightly lower in RGSV-infected rice leaves than in normal rice. Large proportions of DMRs were distributed in the promoter and intergenic regions, and most DMRs were enriched in the CHH context, where the number of CHH hypo-DMRs was almost twice as high as that of hyper-DMRs. Among the genes with down-regulated expression and hypermethylation, we analyzed and identified 11 transcripts involved in fertility, plant height and tillering, and among the transcribed up-regulated and hypermethylated genes, we excavated 7 transcripts related to fertility, plant height and tillering. By analyzing the changes of histone H3K9me3 modification before and after virus infestation, we found that the distribution of H3K9me3 modification in the whole rice genome was prevalent, mainly concentrated in the gene promoter and gene body regions, which was distinctly different from the characteristics of animals. Combined with transcriptomic data, H3K9me3 mark was found to favor targeting highly expressed genes. After RGSV infection, H3K9me3 modifications in several regions of CTK and BR hormone signaling-related genes were altered, providing important targets for subsequent studies.
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Affiliation(s)
- Xiaoqing Wu
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Hongfei Liu
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Bi Lian
- Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xue Jiang
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Cheng Chen
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Tianxin Tang
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xinlun Ding
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jie Hu
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shanshan Zhao
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Shuai Zhang
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Jianguo Wu
- Vector-borne Virus Research Center, Key Laboratory of Plant Virology of Fujian Province, Institute of Plant Virology, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, China
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27
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Jing X, Xu L, Huai X, Zhang H, Zhao F, Qiao Y. Genome-Wide Identification and Characterization of Argonaute, Dicer-like and RNA-Dependent RNA Polymerase Gene Families and Their Expression Analyses in Fragaria spp. Genes (Basel) 2023; 14:genes14010121. [PMID: 36672862 PMCID: PMC9859564 DOI: 10.3390/genes14010121] [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: 11/21/2022] [Revised: 12/19/2022] [Accepted: 12/29/2022] [Indexed: 01/04/2023] Open
Abstract
In the growth and development of plants, some non-coding small RNAs (sRNAs) not only mediate RNA interference at the post-transcriptional level, but also play an important regulatory role in chromatin modification at the transcriptional level. In these processes, the protein factors Argonaute (AGO), Dicer-like (DCL), and RNA-dependent RNA polymerase (RDR) play very important roles in the synthesis of sRNAs respectively. Though they have been identified in many plants, the information about these gene families in strawberry was poorly understood. In this study, using a genome-wide analysis and a phylogenetic approach, 13 AGO, six DCL, and nine RDR genes were identified in diploid strawberry Fragaria vesca. We also identified 33 AGO, 18 DCL, and 28 RDR genes in octoploid strawberry Fragaria × ananassa, studied the expression patterns of these genes in various tissues and developmental stages of strawberry, and researched the response of these genes to some hormones, finding that almost all genes respond to the five hormone stresses. This study is the first report of a genome-wide analysis of AGO, DCL, and RDR gene families in Fragaria spp., in which we provide basic genomic information and expression patterns for these genes. Additionally, this study provides a basis for further research on the functions of these genes and some evidence for the evolution between diploid and octoploid strawberries.
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Affiliation(s)
- Xiaotong Jing
- Laboratory of Fruit Crop Biotechnology, College of Horticulture, Nanjing Agricultural University, No. 1 Weigang, Nanjing 210095, China
| | - Linlin Xu
- Institute of Pomology, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
| | - Xinjia Huai
- Laboratory of Fruit Crop Biotechnology, College of Horticulture, Nanjing Agricultural University, No. 1 Weigang, Nanjing 210095, China
| | - Hong Zhang
- Laboratory of Fruit Crop Biotechnology, College of Horticulture, Nanjing Agricultural University, No. 1 Weigang, Nanjing 210095, China
| | - Fengli Zhao
- Laboratory of Fruit Crop Biotechnology, College of Horticulture, Nanjing Agricultural University, No. 1 Weigang, Nanjing 210095, China
| | - Yushan Qiao
- Laboratory of Fruit Crop Biotechnology, College of Horticulture, Nanjing Agricultural University, No. 1 Weigang, Nanjing 210095, China
- Institute of Pomology, Jiangsu Academy of Agricultural Sciences/Jiangsu Key Laboratory for Horticultural Crop Genetic Improvement, Nanjing 210014, China
- Correspondence:
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28
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Liu W, Shoji K, Naganuma M, Tomari Y, Iwakawa HO. The mechanisms of siRNA selection by plant Argonaute proteins triggering DNA methylation. Nucleic Acids Res 2022; 50:12997-13010. [PMID: 36477368 PMCID: PMC9825178 DOI: 10.1093/nar/gkac1135] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 11/03/2022] [Accepted: 11/11/2022] [Indexed: 12/12/2022] Open
Abstract
The model plant Arabidopsis thaliana encodes as many as ten Argonaute proteins (AGO1-10) with different functions. Each AGO selectively loads a set of small RNAs by recognizing their length and 5' nucleotide identity to properly regulate target genes. Previous studies showed that AGO4 and AGO6, key factors in DNA methylation, incorporate 24-nt small-interfering RNAs with 5' adenine (24A siRNAs). However, it has been unclear how these AGOs specifically load 24A siRNAs. Here, we biochemically investigated the siRNA preference of AGO4, AGO6 and their chimeric mutants. We found that AGO4 and AGO6 use distinct mechanisms to preferentially load 24A siRNAs. Moreover, we showed that the 5' A specificity of AGO4 and AGO6 is not determined by the previously known nucleotide specificity loop in the MID domain but rather by the coordination of the MID and PIWI domains. These findings advance our mechanistic understanding of how small RNAs are accurately sorted into different AGO proteins in plants.
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Affiliation(s)
- Wei Liu
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Keisuke Shoji
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Masahiro Naganuma
- RIKEN Center for Biosystems Dynamics Research, Yokohama, Kanagawa 230-0045, Japan
| | - Yukihide Tomari
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Hiro-oki Iwakawa
- Department of Life Science, College of Science, Rikkyo University, Toshima-ku, Tokyo 171-8501, Japan
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29
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Shao Z, Huang L, Zhang Y, Qiang S, Song X. Transgene Was Silenced in Hybrids between Transgenic Herbicide-Resistant Crops and Their Wild Relatives Utilizing Alien Chromosomes. PLANTS (BASEL, SWITZERLAND) 2022; 11:3187. [PMID: 36501227 PMCID: PMC9741405 DOI: 10.3390/plants11233187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2022] [Revised: 11/13/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
The commercialization of transgenic herbicide-resistant (HR) crops may cause gene flow risk. If a transgene in progenies of transgenic crops and wild relatives is silencing, these progenies should be killed by the target herbicide, thus, the gene flow risk could be decreased. We obtained the progenies of backcross generations between wild Brassca juncea (AABB, 2n = 36) and glufosinate-resistant transgenic Brassica napus (AACC, 2n = 38, PAT gene located on the C-chromosome). They carried the HR gene but did not express it normally, i.e., gene silencing occurred. Meanwhile, six to nine methylation sites were found on the promoter of PAT in transgene-silencing progenies, while no methylation sites occurred on that in transgene-expressing progenies. In addition, transgene expressing and silencing backcross progenies showed similar fitness with wild Brassica juncea. In conclusion, we elaborate on the occurrence of transgene-silencing event in backcross progenies between transgenic crop utilizing alien chromosomes and their wild relatives, and the DNA methylation of the transgene promoter was an important factor leading to gene silencing. The insertion site of the transgene could be considered a strategy to reduce the ecological risk of transgenic crops, and applied to cultivate lower gene flow HR crops in the future.
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Affiliation(s)
| | | | | | | | - Xiaoling Song
- Weed Research Laboratory, College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China; (Z.S.); (L.H.); (Y.Z.); (S.Q.)
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30
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Kong X, Yang M, Le BH, He W, Hou Y. The master role of siRNAs in plant immunity. MOLECULAR PLANT PATHOLOGY 2022; 23:1565-1574. [PMID: 35869407 PMCID: PMC9452763 DOI: 10.1111/mpp.13250] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2021] [Revised: 06/18/2022] [Accepted: 06/21/2022] [Indexed: 06/01/2023]
Abstract
Gene silencing mediated by small noncoding RNAs (sRNAs) is a fundamental gene regulation mechanism in eukaryotes that broadly governs cellular processes. It has been established that sRNAs are critical regulators of plant growth, development, and antiviral defence, while accumulating studies support positive roles of sRNAs in plant defence against bacteria and eukaryotic pathogens such as fungi and oomycetes. Emerging evidence suggests that plant sRNAs move between species and function as antimicrobial agents against nonviral parasites. Multiple plant pathosystems have been shown to involve a similar exchange of small RNAs between species. Recent analysis about extracellular sRNAs shed light on the understanding of the selection and transportation of sRNAs moving from plant to parasites. In this review, we summarize current advances regarding the function and regulatory mechanism of plant endogenous small interfering RNAs (siRNAs) in mediating plant defence against pathogen intruders including viruses, bacteria, fungi, oomycetes, and parasitic plants. Beyond that, we propose potential mechanisms behind the sorting of sRNAs moving between species and the idea that engineering siRNA-producing loci could be a useful strategy to improve disease resistance of crops.
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Affiliation(s)
- Xiuzhen Kong
- Shanghai Collaborative Innovation Center of Agri‐Seeds/School of Agriculture and BiologyShanghai Jiao Tong UniversityShanghaiChina
| | - Meng Yang
- Shanghai Collaborative Innovation Center of Agri‐Seeds/School of Agriculture and BiologyShanghai Jiao Tong UniversityShanghaiChina
| | - Brandon H. Le
- Department of Botany and Plant Sciences, Institute of Integrative Genome BiologyUniversity of CaliforniaRiversideCaliforniaUSA
| | - Wenrong He
- Plant Molecular and Cellular Biology LaboratorySalk Institute for Biological StudiesLa JollaCaliforniaUSA
| | - Yingnan Hou
- Shanghai Collaborative Innovation Center of Agri‐Seeds/School of Agriculture and BiologyShanghai Jiao Tong UniversityShanghaiChina
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31
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Kumar M, Tripathi PK, Ayzenshtat D, Marko A, Forotan Z, Bocobza SE. Increased rates of gene-editing events using a simplified RNAi configuration designed to reduce gene silencing. PLANT CELL REPORTS 2022; 41:1987-2003. [PMID: 35849200 DOI: 10.1007/s00299-022-02903-9] [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: 05/25/2022] [Accepted: 06/30/2022] [Indexed: 06/15/2023]
Abstract
An optimal RNAi configuration that could restrict gene expression most efficiently was determined. This approach was also used to target PTGS and yielded higher rates of gene-editing events. Although it was characterized long ago, transgene silencing still strongly impairs transgene overexpression, and thus is a major barrier to plant crop gene-editing. The development of strategies that could prevent transgene silencing is therefore essential to the success of gene editing assays. Transgene silencing occurs via the RNA silencing process, which regulates the expression of essential genes and protects the plant from viral infections. The RNA silencing machinery thereby controls central biological processes such as growth, development, genome integrity, and stress resistance. RNA silencing is typically induced by aberrant RNA, that may lack 5' or 3' processing, or may consist in double-stranded or hairpin RNA, and involves DICER and ARGONAUTE family proteins. In this study, RNAi inducing constructs were designed in eleven different configurations and were evaluated for their capacity to induce silencing in Nicotiana spp. using transient and stable transformation assays. Using reporter genes, it was found that the overexpression of a hairpin consisting of a forward tandem inverted repeat that started with an ATG and that was not followed downstream by a transcription terminator, could downregulate gene expression most potently. Furthermore, using this method, the downregulation of the NtSGS3 gene caused a significant increase in transgene expression both in transient and stable transformation assays. This SGS3 silencing approach was also employed in gene-editing assays and caused higher rates of gene-editing events. Taken together, these findings suggested the optimal genetic configuration to cause RNA silencing and showed that this strategy may be used to restrict PTGS during gene-editing experiments.
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Affiliation(s)
- Manoj Kumar
- Department of Ornamental Plants and Agricultural Biotechnology, The Institute of Plant Sciences, The Volcani Center, ARO, Beit Dagan, Israel
| | - Pankaj Kumar Tripathi
- Department of Ornamental Plants and Agricultural Biotechnology, The Institute of Plant Sciences, The Volcani Center, ARO, Beit Dagan, Israel
| | - Dana Ayzenshtat
- Department of Ornamental Plants and Agricultural Biotechnology, The Institute of Plant Sciences, The Volcani Center, ARO, Beit Dagan, Israel
| | - Adar Marko
- Department of Ornamental Plants and Agricultural Biotechnology, The Institute of Plant Sciences, The Volcani Center, ARO, Beit Dagan, Israel
| | - Zohar Forotan
- Department of Ornamental Plants and Agricultural Biotechnology, The Institute of Plant Sciences, The Volcani Center, ARO, Beit Dagan, Israel
| | - Samuel E Bocobza
- Department of Ornamental Plants and Agricultural Biotechnology, The Institute of Plant Sciences, The Volcani Center, ARO, Beit Dagan, Israel.
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32
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Chakraborty T, Payne H, Mosher RA. Expansion and contraction of small RNA and methylation machinery throughout plant evolution. CURRENT OPINION IN PLANT BIOLOGY 2022; 69:102260. [PMID: 35849937 DOI: 10.1016/j.pbi.2022.102260] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/09/2022] [Accepted: 06/14/2022] [Indexed: 06/15/2023]
Abstract
The revolution in sequencing has created a wealth of plant genomes that can be mined to understand the evolution of biological complexity. Complexity is often driven by gene duplication, which allows paralogs to specialize in an activity of the ancestral gene or acquire novel functions. Angiosperms encode a variety of gene silencing pathways that share related machinery for small RNA biosynthesis and function. Recent phylogenetic analysis of these gene families plots the expansion, specialization, and occasional contraction of this core machinery. This analysis reveals the ancient origin of RNA-directed DNA Methylation in early land plants, or possibly their algal ancestors, as well as ongoing duplications that evolve novel small RNA pathways.
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Affiliation(s)
- Tania Chakraborty
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721-0036, USA
| | - Hayden Payne
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721-0036, USA
| | - Rebecca A Mosher
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721-0036, USA.
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33
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Burgess D, Chow HT, Grover JW, Freeling M, Mosher RA. Ovule siRNAs methylate protein-coding genes in trans. THE PLANT CELL 2022; 34:3647-3664. [PMID: 35781738 PMCID: PMC9516104 DOI: 10.1093/plcell/koac197] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 06/24/2022] [Indexed: 05/31/2023]
Abstract
Twenty-four-nucleotide (nt) small interfering RNAs (siRNAs) maintain asymmetric DNA methylation at thousands of euchromatic transposable elements in plant genomes in a process called RNA-directed DNA methylation (RdDM). RdDM is dispensable for growth and development in Arabidopsis thaliana, but is required for reproduction in other plants, such as Brassica rapa. The 24-nt siRNAs are abundant in maternal reproductive tissue, due largely to overwhelming expression from a few loci in the ovule and developing seed coat, termed siren loci. A recent study showed that 24-nt siRNAs produced in the anther tapetal tissue can methylate male meiocyte genes in trans. Here we show that in B. rapa, a similar process takes place in female tissue. siRNAs are produced from gene fragments embedded in some siren loci, and these siRNAs can trigger methylation in trans at related protein-coding genes. This trans-methylation is associated with silencing of some target genes and may be responsible for seed abortion in RdDM mutants. Furthermore, we demonstrate that a consensus sequence in at least two families of DNA transposons is associated with abundant siren expression, most likely through recruitment of CLASSY3, a putative chromatin remodeler. This research describes a mechanism whereby RdDM influences gene expression and sheds light on the role of RdDM during plant reproduction.
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34
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Aubert J, Bellegarde F, Oltehua-Lopez O, Leblanc O, Arteaga-Vazquez MA, Martienssen RA, Grimanelli D. AGO104 is a RdDM effector of paramutation at the maize b1 locus. PLoS One 2022; 17:e0273695. [PMID: 36040902 PMCID: PMC9426929 DOI: 10.1371/journal.pone.0273695] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 08/12/2022] [Indexed: 11/19/2022] Open
Abstract
Although paramutation has been well-studied at a few hallmark loci involved in anthocyanin biosynthesis in maize, the cellular and molecular mechanisms underlying the phenomenon remain largely unknown. Previously described actors of paramutation encode components of the RNA-directed DNA-methylation (RdDM) pathway that participate in the biogenesis of 24-nucleotide small interfering RNAs (24-nt siRNAs) and long non-coding RNAs. In this study, we uncover an ARGONAUTE (AGO) protein as an effector of the RdDM pathway that is in charge of guiding 24-nt siRNAs to their DNA target to create de novo DNA methylation. We combined immunoprecipitation, small RNA sequencing and reverse genetics to, first, validate AGO104 as a member of the RdDM effector complex and, then, investigate its role in paramutation. We found that AGO104 binds 24-nt siRNAs involved in RdDM, including those required for paramutation at the b1 locus. We also show that the ago104-5 mutation causes a partial reversion of the paramutation phenotype at the b1 locus, revealed by intermediate pigmentation levels in stem tissues. Therefore, our results place AGO104 as a new member of the RdDM effector complex that plays a role in paramutation at the b1 locus in maize.
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Affiliation(s)
- Juliette Aubert
- DIADE, University of Montpellier, CIRAD, IRD, Montpellier, France
| | - Fanny Bellegarde
- DIADE, University of Montpellier, CIRAD, IRD, Montpellier, France
| | | | - Olivier Leblanc
- DIADE, University of Montpellier, CIRAD, IRD, Montpellier, France
| | | | - Robert A. Martienssen
- Howard Hughes Medical Institute, Cold Spring Harbor Laboratory, Cold Spring Harbor, New York, New York, United States of America
| | - Daniel Grimanelli
- DIADE, University of Montpellier, CIRAD, IRD, Montpellier, France
- * E-mail:
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Zand Karimi H, Innes RW. Molecular mechanisms underlying host-induced gene silencing. THE PLANT CELL 2022; 34:3183-3199. [PMID: 35666177 PMCID: PMC9421479 DOI: 10.1093/plcell/koac165] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Accepted: 05/08/2022] [Indexed: 05/05/2023]
Abstract
Host-induced gene silencing (HIGS) refers to the silencing of genes in pathogens and pests by expressing homologous double-stranded RNAs (dsRNA) or artificial microRNAs (amiRNAs) in the host plant. The discovery of such trans-kingdom RNA silencing has enabled the development of RNA interference-based approaches for controlling diverse crop pathogens and pests. Although HIGS is a promising strategy, the mechanisms by which these regulatory RNAs translocate from plants to pathogens, and how they induce gene silencing in pathogens, are poorly understood. This lack of understanding has led to large variability in the efficacy of various HIGS treatments. This variability is likely due to multiple factors, such as the ability of the target pathogen or pest to take up and/or process RNA from the host, the specific genes and target sequences selected in the pathogen or pest for silencing, and where, when, and how the dsRNAs or amiRNAs are produced and translocated. In this review, we summarize what is currently known about the molecular mechanisms underlying HIGS, identify key unanswered questions, and explore strategies for improving the efficacy and reproducibility of HIGS treatments in the control of crop diseases.
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Affiliation(s)
- Hana Zand Karimi
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA
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Chakraborty T, Trujillo JT, Kendall T, Mosher RA. A null allele of the pol IV second subunit impacts stature and reproductive development in Oryza sativa. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 111:748-755. [PMID: 35635763 DOI: 10.1111/tpj.15848] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
All eukaryotes possess three DNA-dependent RNA polymerases, Pols I-III, while land plants possess two additional polymerases, Pol IV and Pol V. Derived through duplication of Pol II subunits, Pol IV produces 24-nt short interfering RNAs that interact with Pol V transcripts to target de novo DNA methylation and silence transcription of transposons. Members of the grass family encode additional duplicated subunits of Pol IV and V, raising questions regarding the function of each paralog. In this study, we identify a null allele of the putative Pol IV second subunit, NRPD2, and demonstrate that NRPD2 is the sole subunit functioning with NRPD1 in small RNA production and CHH methylation in leaves. Homozygous nrpd2 mutants have neither gametophytic defects nor embryo lethality, although adult plants are dwarf and sterile.
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Affiliation(s)
- Tania Chakraborty
- School of Plant Sciences, University of Arizona, Tucson, Arizona, 85721, USA
| | - Joshua T Trujillo
- Department of Biochemistry, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Timmy Kendall
- School of Plant Sciences, University of Arizona, Tucson, Arizona, 85721, USA
| | - Rebecca A Mosher
- School of Plant Sciences, University of Arizona, Tucson, Arizona, 85721, USA
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37
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Small regulatory RNAs in rice epigenetic regulation. Biochem Soc Trans 2022; 50:1215-1225. [PMID: 35579290 DOI: 10.1042/bst20210336] [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: 03/30/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 11/17/2022]
Abstract
Plant small RNAs (sRNAs) are short non-coding RNAs that are implicated in various regulatory processes involving post-transcriptional gene silencing and epigenetic gene regulation. In epigenetic regulation, sRNAs are primarily involved in RNA-directed DNA methylation (RdDM) pathways. sRNAs in the RdDM pathways play a role not only in the suppression of transposable element (TE) activity but also in gene expression regulation. Although the major components of the RdDM pathways have been well studied in Arabidopsis, recent studies have revealed that the RdDM pathways in rice have important biological functions in stress response and developmental processes. In this review, we summarize and discuss recent literature on sRNA-mediated epigenetic regulation in rice. First, we describe the RdDM mechanisms in plants. We then introduce recent discoveries on the biological roles of rice genes involved in the RdDM pathway and TE-derived sRNAs working at specific genomic loci for epigenetic control in rice.
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Akbar S, Wei Y, Zhang MQ. RNA Interference: Promising Approach to Combat Plant Viruses. Int J Mol Sci 2022; 23:ijms23105312. [PMID: 35628126 PMCID: PMC9142109 DOI: 10.3390/ijms23105312] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2022] [Revised: 05/06/2022] [Accepted: 05/07/2022] [Indexed: 11/16/2022] Open
Abstract
Plant viruses are devastating plant pathogens that severely affect crop yield and quality. Plants have developed multiple lines of defense systems to combat viral infection. Gene silencing/RNA interference is the key defense system in plants that inhibits the virulence and multiplication of pathogens. The general mechanism of RNAi involves (i) the transcription and cleavage of dsRNA into small RNA molecules, such as microRNA (miRNA), or small interfering RNA (siRNA), (ii) the loading of siRNA/miRNA into an RNA Induced Silencing Complex (RISC), (iii) complementary base pairing between siRNA/miRNA with a targeted gene, and (iv) the cleavage or repression of a target gene with an Argonaute (AGO) protein. This natural RNAi pathway could introduce transgenes targeting various viral genes to induce gene silencing. Different RNAi pathways are reported for the artificial silencing of viral genes. These include Host-Induced Gene Silencing (HIGS), Virus-Induced Gene Silencing (VIGS), and Spray-Induced Gene Silencing (SIGS). There are significant limitations in HIGS and VIGS technology, such as lengthy and time-consuming processes, off-target effects, and public concerns regarding genetically modified (GM) transgenic plants. Here, we provide in-depth knowledge regarding SIGS, which efficiently provides RNAi resistance development against targeted genes without the need for GM transgenic plants. We give an overview of the defense system of plants against viral infection, including a detailed mechanism of RNAi, small RNA molecules and their types, and various kinds of RNAi pathways. This review will describe how RNA interference provides the antiviral defense, recent improvements, and their limitations.
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Affiliation(s)
- Sehrish Akbar
- Guangxi Key Laboratory for Sugarcane Biology & State Key Laboratory for Conservation and Utilization of Agro Bioresources, Guangxi University, Nanning 530005, China; (S.A.); (Y.W.)
| | - Yao Wei
- Guangxi Key Laboratory for Sugarcane Biology & State Key Laboratory for Conservation and Utilization of Agro Bioresources, Guangxi University, Nanning 530005, China; (S.A.); (Y.W.)
| | - Mu-Qing Zhang
- Guangxi Key Laboratory for Sugarcane Biology & State Key Laboratory for Conservation and Utilization of Agro Bioresources, Guangxi University, Nanning 530005, China; (S.A.); (Y.W.)
- IRREC-IFAS, University of Florida, Fort Pierce, FL 34945, USA
- Correspondence: or
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Xu Y, Ji X, Xu Z, Yuan Y, Chen X, Kong D, Zhang Y, Sun D. Transcriptome Profiling Reveals a Petunia Transcription Factor, PhCOL4, Contributing to Antiviral RNA Silencing. FRONTIERS IN PLANT SCIENCE 2022; 13:876428. [PMID: 35498675 PMCID: PMC9047179 DOI: 10.3389/fpls.2022.876428] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 03/21/2022] [Indexed: 06/12/2023]
Abstract
RNA silencing is a common antiviral mechanism in eukaryotic organisms. However, the transcriptional regulatory mechanism that controls the RNA silencing process remains elusive. Here, we performed high-depth transcriptome analysis on petunia (Petunia hybrida) leaves infected with tobacco rattle virus (TRV) strain PPK20. A total of 7,402 differentially expressed genes (DEGs) were identified. Of them, some RNA silencing-related transcripts, such as RNA-dependent RNA polymerases (RDRs), Dicer-like RNase III enzymes (DCLs), and Argonautes (AGOs), were induced by viral attack. Furthermore, we performed TRV-based virus-induced gene silencing (VIGS) assay on 39 DEGs encoding putative transcription factors (TFs), using green fluorescent protein (GFP) and phytoene desaturase (PhPDS) as reporters. Results showed that the down-regulation of PhbHLH41, PhbHLH93, PhZPT4-3, PhCOL4, PhHSF-B3A, PhNAC90, and PhWRKY75 led to enhanced TRV accumulation and inhibited PhPDS-silenced photobleaching phenotype. In contrast, silencing of PhERF22 repressed virus accumulation and promoted photobleaching development. Thus, these TFs were identified as potential positive and negative regulators of antiviral RNA silencing, respectively. One positive regulator PhCOL4, belonging to the B-box zinc finger family, was selected for further functional characterization. Silencing and transient overexpression of PhCOL4 resulted in decreased and increased expression of several RNA silencing-related genes. DNA affinity purification sequencing analysis revealed that PhCOL4 targeted PhRDR6 and PhAGO4. Dual luciferase and yeast one-hybrid assays determined the binding of PhCOL4 to the PhRDR6 and PhAGO4 promoters. Our findings suggest that TRV-GFP-PhPDS-based VIGS could be helpful to identify transcriptional regulators of antiviral RNA silencing.
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Affiliation(s)
- Yingru Xu
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Xiaotong Ji
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Zhuangzhuang Xu
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Yanping Yuan
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Xiling Chen
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Derong Kong
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
| | - Yanlong Zhang
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
- National Engineering Technology Research Center for Oil Peony, Northwest A&F University, Yangling, China
| | - Daoyang Sun
- College of Landscape Architecture and Arts, Northwest A&F University, Yangling, China
- National Engineering Technology Research Center for Oil Peony, Northwest A&F University, Yangling, China
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Multi-omics data integration reveals link between epigenetic modifications and gene expression in sugar beet (Beta vulgaris subsp. vulgaris) in response to cold. BMC Genomics 2022; 23:144. [PMID: 35176993 PMCID: PMC8855596 DOI: 10.1186/s12864-022-08312-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Accepted: 01/13/2022] [Indexed: 12/19/2022] Open
Abstract
Background DNA methylation is thought to influence the expression of genes, especially in response to changing environmental conditions and developmental changes. Sugar beet (Beta vulgaris ssp. vulgaris), and other biennial or perennial plants are inevitably exposed to fluctuating temperatures throughout their lifecycle and might even require such stimulus to acquire floral competence. Therefore, plants such as beets, need to fine-tune their epigenetic makeup to ensure phenotypic plasticity towards changing environmental conditions while at the same time steering essential developmental processes. Different crop species may show opposing reactions towards the same abiotic stress, or, vice versa, identical species may respond differently depending on the specific kind of stress. Results In this study, we investigated common effects of cold treatment on genome-wide DNA methylation and gene expression of two Beta vulgaris accessions via multi-omics data analysis. Cold exposure resulted in a pronounced reduction of DNA methylation levels, which particularly affected methylation in CHH context (and to a lesser extent CHG) and was accompanied by transcriptional downregulation of the chromomethyltransferase CMT2 and strong upregulation of several genes mediating active DNA demethylation. Conclusion Integration of methylomic and transcriptomic data revealed that, rather than methylation having directly influenced expression, epigenetic modifications correlated with changes in expression of known players involved in DNA (de)methylation. In particular, cold triggered upregulation of genes putatively contributing to DNA demethylation via the ROS1 pathway. Our observations suggest that these transcriptional responses precede the cold-induced global DNA-hypomethylation in non-CpG, preparing beets for additional transcriptional alterations necessary for adapting to upcoming environmental changes. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08312-2.
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Rebolledo-Prudencio OG, Estrada-Rivera M, Dautt-Castro M, Arteaga-Vazquez MA, Arenas-Huertero C, Rosendo-Vargas MM, Jin H, Casas-Flores S. The small RNA-mediated gene silencing machinery is required in Arabidopsis for stimulation of growth, systemic disease resistance, and suppression of the nitrile-specifier gene NSP4 by Trichoderma atroviride. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:873-890. [PMID: 34807478 DOI: 10.1111/tpj.15599] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 11/09/2021] [Accepted: 11/15/2021] [Indexed: 06/13/2023]
Abstract
Trichoderma atroviride is a root-colonizing fungus that confers multiple benefits to plants. In plants, small RNA (sRNA)-mediated gene silencing (sRNA-MGS) plays pivotal roles in growth, development, and pathogen attack. Here, we explored the role of core components of Arabidopsis thaliana sRNA-MGS pathways during its interaction with Trichoderma. Upon interaction with Trichoderma, sRNA-MGS-related genes paralleled the expression of Arabidopsis defense-related genes, linked to salicylic acid (SA) and jasmonic acid (JA) pathways. SA- and JA-related genes were primed by Trichoderma in leaves after the application of the well-known pathogen-associated molecular patterns flg22 and chitin, respectively. Defense-related genes were primed in roots as well, but to different extents and behaviors. Phenotypical characterization of mutants in AGO genes and components of the RNA-dependent DNA methylation (RdDM) pathway revealed that different sets of sRNA-MGS-related genes are essential for (i) the induction of systemic acquired resistance against Botrytis cinerea, (ii) the activation of the expression of plant defense-related genes, and (iii) root colonization by Trichoderma. Additionally, plant growth induced by Trichoderma depends on functional RdDM. Profiling of DNA methylation and histone N-tail modification patterns at the Arabidopsis Nitrile-Specifier Protein-4 (NSP4) locus, which is responsive to Trichoderma, showed altered epigenetic modifications in RdDM mutants. Furthermore, NSP4 is required for the induction of systemic acquired resistance against Botrytis and avoidance of enhanced root colonization by Trichoderma. Together, our results indicate that RdDM is essential in Arabidopsis to establish a beneficial relationship with Trichoderma. We propose that DNA methylation and histone modifications are required for plant priming by the beneficial fungus against B. cinerea.
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Affiliation(s)
- Oscar Guillermo Rebolledo-Prudencio
- División de Biología Molecular, IPICYT, Camino a la presa San José No. 2055, Colonia Lomas 4ª Sección, San Luis Potosí, S.L.P., C.P. 78216, Mexico
| | - Magnolia Estrada-Rivera
- División de Biología Molecular, IPICYT, Camino a la presa San José No. 2055, Colonia Lomas 4ª Sección, San Luis Potosí, S.L.P., C.P. 78216, Mexico
| | - Mitzuko Dautt-Castro
- División de Biología Molecular, IPICYT, Camino a la presa San José No. 2055, Colonia Lomas 4ª Sección, San Luis Potosí, S.L.P., C.P. 78216, Mexico
| | - Mario A Arteaga-Vazquez
- Universidad Veracruzana, INBIOTECA-Instituto de Biotecnología y Ecología Aplicada, Av. de las Culturas Veracruzanas No. 101, Colonia Emiliano Zapata, Xalapa, Veracruz, C.P. 91090, Mexico
| | - Catalina Arenas-Huertero
- Facultad de Ciencias, Universidad Autónoma de San Luis Potosí, Av. Chapultepec #1570, Priv del Pedregal., San Luis Potosí, S.L.P., C.P. 78295, Mexico
| | - Maria Montserrat Rosendo-Vargas
- División de Biología Molecular, IPICYT, Camino a la presa San José No. 2055, Colonia Lomas 4ª Sección, San Luis Potosí, S.L.P., C.P. 78216, Mexico
| | - Hailing Jin
- Department of Plant Pathology and Microbiology, Center for Plant Cell Biology, Institute for Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - Sergio Casas-Flores
- División de Biología Molecular, IPICYT, Camino a la presa San José No. 2055, Colonia Lomas 4ª Sección, San Luis Potosí, S.L.P., C.P. 78216, Mexico
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Loffer A, Singh J, Fukudome A, Mishra V, Wang F, Pikaard CS. A DCL3 dicing code within Pol IV-RDR2 transcripts diversifies the siRNA pool guiding RNA-directed DNA methylation. eLife 2022; 11:e73260. [PMID: 35098919 PMCID: PMC8846587 DOI: 10.7554/elife.73260] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Accepted: 01/28/2022] [Indexed: 11/26/2022] Open
Abstract
In plants, selfish genetic elements, including retrotransposons and DNA viruses, are transcriptionally silenced by RNA-directed DNA methylation. Guiding the process are short interfering RNAs (siRNAs) cut by DICER-LIKE 3 (DCL3) from double-stranded precursors of ~30 bp that are synthesized by NUCLEAR RNA POLYMERASE IV (Pol IV) and RNA-DEPENDENT RNA POLYMERASE 2 (RDR2). We show that Pol IV's choice of initiating nucleotide, RDR2's initiation 1-2 nt internal to Pol IV transcript ends and RDR2's terminal transferase activity collectively yield a code that influences which precursor end is diced and whether 24 or 23 nt siRNAs are produced. By diversifying the size, sequence, and strand specificity of siRNAs derived from a given precursor, alternative patterns of DCL3 dicing allow for maximal siRNA coverage at methylated target loci.
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Affiliation(s)
- Andrew Loffer
- Department of Biology and Department of Molecular and Cellular Biochemistry, Indiana University BloomingtonBloomingtonUnited States
| | - Jasleen Singh
- Department of Biology and Department of Molecular and Cellular Biochemistry, Indiana University BloomingtonBloomingtonUnited States
| | - Akihito Fukudome
- Department of Biology and Department of Molecular and Cellular Biochemistry, Indiana University BloomingtonBloomingtonUnited States
- Howard Hughes Medical Institute, Indiana UniversityBloomingtonUnited States
| | - Vibhor Mishra
- Department of Biology and Department of Molecular and Cellular Biochemistry, Indiana University BloomingtonBloomingtonUnited States
- Howard Hughes Medical Institute, Indiana UniversityBloomingtonUnited States
| | - Feng Wang
- Department of Biology and Department of Molecular and Cellular Biochemistry, Indiana University BloomingtonBloomingtonUnited States
- Howard Hughes Medical Institute, Indiana UniversityBloomingtonUnited States
| | - Craig S Pikaard
- Department of Biology and Department of Molecular and Cellular Biochemistry, Indiana University BloomingtonBloomingtonUnited States
- Howard Hughes Medical Institute, Indiana UniversityBloomingtonUnited States
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Alvarez-Diaz JC, Richard MMS, Thareau V, Teano G, Paysant-Le-Roux C, Rigaill G, Pflieger S, Gratias A, Geffroy V. Genome-Wide Identification of Key Components of RNA Silencing in Two Phaseolus vulgaris Genotypes of Contrasting Origin and Their Expression Analyses in Response to Fungal Infection. Genes (Basel) 2021; 13:genes13010064. [PMID: 35052407 PMCID: PMC8774654 DOI: 10.3390/genes13010064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 12/22/2021] [Accepted: 12/23/2021] [Indexed: 12/13/2022] Open
Abstract
RNA silencing serves key roles in a multitude of cellular processes, including development, stress responses, metabolism, and maintenance of genome integrity. Dicer, Argonaute (AGO), double-stranded RNA binding (DRB) proteins, RNA-dependent RNA polymerase (RDR), and DNA-dependent RNA polymerases known as Pol IV and Pol V form core components to trigger RNA silencing. Common bean (Phaseolus vulgaris) is an important staple crop worldwide. In this study, we aimed to unravel the components of the RNA-guided silencing pathway in this non-model plant, taking advantage of the availability of two genome assemblies of Andean and Meso-American origin. We identified six PvDCLs, thirteen PvAGOs, 10 PvDRBs, 5 PvRDRs, in both genotypes, suggesting no recent gene amplification or deletion after the gene pool separation. In addition, we identified one PvNRPD1 and one PvNRPE1 encoding the largest subunits of Pol IV and Pol V, respectively. These genes were categorized into subgroups based on phylogenetic analyses. Comprehensive analyses of gene structure, genomic localization, and similarity among these genes were performed. Their expression patterns were investigated by means of expression models in different organs using online data and quantitative RT-PCR after pathogen infection. Several of the candidate genes were up-regulated after infection with the fungus Colletotrichum lindemuthianum.
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Affiliation(s)
- Juan C. Alvarez-Diaz
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France; (J.C.A.-D.); (M.M.S.R.); (V.T.); (G.T.); (C.P.-L.-R.); (G.R.); (S.P.); (A.G.)
- Université de Paris, Institute of Plant Sciences Paris Saclay (IPS2), 91405 Orsay, France
| | - Manon M. S. Richard
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France; (J.C.A.-D.); (M.M.S.R.); (V.T.); (G.T.); (C.P.-L.-R.); (G.R.); (S.P.); (A.G.)
- Université de Paris, Institute of Plant Sciences Paris Saclay (IPS2), 91405 Orsay, France
- Molecular Plant Pathology, Swammerdam Institute for Life Sciences (SILS), University of Amsterdam, 1098 XH Amsterdam, The Netherlands
| | - Vincent Thareau
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France; (J.C.A.-D.); (M.M.S.R.); (V.T.); (G.T.); (C.P.-L.-R.); (G.R.); (S.P.); (A.G.)
- Université de Paris, Institute of Plant Sciences Paris Saclay (IPS2), 91405 Orsay, France
| | - Gianluca Teano
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France; (J.C.A.-D.); (M.M.S.R.); (V.T.); (G.T.); (C.P.-L.-R.); (G.R.); (S.P.); (A.G.)
- Université de Paris, Institute of Plant Sciences Paris Saclay (IPS2), 91405 Orsay, France
| | - Christine Paysant-Le-Roux
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France; (J.C.A.-D.); (M.M.S.R.); (V.T.); (G.T.); (C.P.-L.-R.); (G.R.); (S.P.); (A.G.)
- Université de Paris, Institute of Plant Sciences Paris Saclay (IPS2), 91405 Orsay, France
| | - Guillem Rigaill
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France; (J.C.A.-D.); (M.M.S.R.); (V.T.); (G.T.); (C.P.-L.-R.); (G.R.); (S.P.); (A.G.)
- Université de Paris, Institute of Plant Sciences Paris Saclay (IPS2), 91405 Orsay, France
- Laboratoire de Mathématiques et Modélisation d’Evry, Université Paris-Saclay, CNRS, Université Evry, INRAE, 91037 Evry, France
| | - Stéphanie Pflieger
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France; (J.C.A.-D.); (M.M.S.R.); (V.T.); (G.T.); (C.P.-L.-R.); (G.R.); (S.P.); (A.G.)
- Université de Paris, Institute of Plant Sciences Paris Saclay (IPS2), 91405 Orsay, France
| | - Ariane Gratias
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France; (J.C.A.-D.); (M.M.S.R.); (V.T.); (G.T.); (C.P.-L.-R.); (G.R.); (S.P.); (A.G.)
- Université de Paris, Institute of Plant Sciences Paris Saclay (IPS2), 91405 Orsay, France
| | - Valérie Geffroy
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91405 Orsay, France; (J.C.A.-D.); (M.M.S.R.); (V.T.); (G.T.); (C.P.-L.-R.); (G.R.); (S.P.); (A.G.)
- Université de Paris, Institute of Plant Sciences Paris Saclay (IPS2), 91405 Orsay, France
- Correspondence: ; Tel.: +33-1-69-15-33-65
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Petrella R, Cucinotta M, Mendes MA, Underwood CJ, Colombo L. The emerging role of small RNAs in ovule development, a kind of magic. PLANT REPRODUCTION 2021; 34:335-351. [PMID: 34142243 PMCID: PMC8566443 DOI: 10.1007/s00497-021-00421-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Accepted: 06/08/2021] [Indexed: 05/03/2023]
Abstract
In plants, small RNAs have been recognized as key genetic and epigenetic regulators of development. Small RNAs are usually 20 to 30 nucleotides in length and they control, in a sequence specific manner, the transcriptional or post-transcriptional expression of genes. In this review, we present a comprehensive overview of the most recent findings about the function of small RNAs in ovule development, including megasporogenesis and megagametogenesis, both in sexual and apomictic plants. We discuss recent studies on the role of miRNAs, siRNAs and trans-acting RNAs (ta-siRNAs) in early female germline differentiation. The mechanistic complexity and unique regulatory features are reviewed, and possible directions for future research are provided.
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Affiliation(s)
- Rosanna Petrella
- Dipartimento di Bioscienze, Università Degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy
| | - Mara Cucinotta
- Dipartimento di Bioscienze, Università Degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy
| | - Marta A Mendes
- Dipartimento di Bioscienze, Università Degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy
| | - Charles J Underwood
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, 50829, Cologne, Germany
| | - Lucia Colombo
- Dipartimento di Bioscienze, Università Degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy.
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Voorburg CM, Bai Y, Kormelink R. Small RNA Profiling of Susceptible and Resistant Ty-1 Encoding Tomato Plants Upon Tomato Yellow Leaf Curl Virus Infection. FRONTIERS IN PLANT SCIENCE 2021; 12:757165. [PMID: 34868151 PMCID: PMC8637622 DOI: 10.3389/fpls.2021.757165] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 10/04/2021] [Indexed: 06/13/2023]
Abstract
Ty-1 presents an atypical dominant resistance gene that codes for an RNA-dependent RNA polymerase (RDR) of the gamma class and confers resistance to tomato yellow leaf curl virus (TYLCV) and other geminiviruses. Tomato lines bearing Ty-1 not only produce relatively higher amounts of viral small interfering (vsi)RNAs, but viral DNA also exhibits a higher amount of cytosine methylation. Whether Ty-1 specifically enhances posttranscriptional gene silencing (PTGS), leading to a degradation of RNA target molecules and primarily relying on 21-22 nucleotides (nts) siRNAs, and/or transcriptional gene silencing (TGS), leading to the methylation of cytosines within DNA target sequences and relying on 24-nts siRNAs, was unknown. In this study, small RNAs were isolated from systemically TYLCV-infected leaves of Ty-1 encoding tomato plants and susceptible tomato Moneymaker (MM) and sequence analyzed. While in susceptible tomato plants vsiRNAs of the 21-nt size class were predominant, their amount was drastically reduced in tomato containing Ty-1. The latter, instead, revealed elevated levels of vsiRNAs of the 22- and 24-nt size classes. In addition, the genomic distribution profiles of the vsiRNAs were changed in Ty-1 plants compared with those from susceptible MM. In MM three clear hotspots were seen, but these were less pronounced in Ty-1 plants, likely due to enhanced transitive silencing to neighboring viral genomic sequences. The largest increase in the amount of vsiRNAs was observed in the intergenic region and the V1 viral gene. The results suggest that Ty-1 enhances an antiviral TGS response. Whether the elevated levels of 22 nts vsiRNAs contribute to an enhanced PTGS response or an additional TGS response involving a noncanonical pathway of RNA dependent DNA methylation remains to be investigated.
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Affiliation(s)
- Corien M. Voorburg
- Laboratory of Virology, Department of Plant Sciences, Wageningen University and Research, Wageningen, Netherlands
| | - Yuling Bai
- Plant Breeding, Department of Plant Sciences, Wageningen University and Research, Wageningen, Netherlands
| | - Richard Kormelink
- Laboratory of Virology, Department of Plant Sciences, Wageningen University and Research, Wageningen, Netherlands
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The RNA Directed DNA Methylation (RdDM) Pathway Regulates Anthocyanin Biosynthesis in Crabapple (Malus cv. spp.) Leaves by Methylating the McCOP1 Promoter. PLANTS 2021; 10:plants10112466. [PMID: 34834829 PMCID: PMC8618851 DOI: 10.3390/plants10112466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 10/25/2021] [Accepted: 10/28/2021] [Indexed: 11/17/2022]
Abstract
The synthesis of anthocyanin pigments in plants is known to be regulated by multiple mechanisms, including epigenetic regulation; however, the contribution of the RNA-directed DNA methylation (RdDM) pathway is not well understood. Here, we used bisulfite sequencing and Real Time (RT)-quantitative (q) PCR to analyze the methylation level of the promoter of constitutively photomorphogenic 1 (McCOP1) from Malus cv. spp, a gene involved in regulating anthocyanin biosynthesis. The CHH methylation level of the McCOP1 promoter was negatively correlated with McCOP1 RNA expression, and inhibiting DNA methylation caused decreased methylation of the McCOP1 promoter and asymmetric cytosine CHH methylation. We observed that the McCOP1 promoter was a direct target of the RdDM pathway argonaute RISC component 4 (McAGO4) protein, which bound to a McCOP1 promoter GGTTCGG site. Bimolecular fluorescence complementation (BIFC) analysis showed that RNA-directed DNA methylation (McRDM1) interacted with McAGO4 and another RdDM protein, domains rearranged methyltransferase 2 (McDRM2), to regulate the CHH methylation of the McCOP1 promoter. Detection of CHH methylation and COP1 gene expression in the Arabidopsis thalianaatago4, atdrm2 and atrdm1 mutants showed that RDM1 is the effector of the RdDM pathway. This was confirmed by silencing McRDM1 in crabapple leaves or apple fruit, which resulted in a decrease in McCOP1 CHH methylation and an increase in McCOP1 transcript levels, as well as in anthocyanin accumulation. In conclusion, these results show that the RdDM pathway is involved in regulating anthocyanin accumulation through CHH methylation of the McCOP1 promoter.
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Sigman MJ, Panda K, Kirchner R, McLain LL, Payne H, Peasari JR, Husbands AY, Slotkin RK, McCue AD. An siRNA-guided ARGONAUTE protein directs RNA polymerase V to initiate DNA methylation. NATURE PLANTS 2021; 7:1461-1474. [PMID: 34750500 PMCID: PMC8592841 DOI: 10.1038/s41477-021-01008-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 09/09/2021] [Indexed: 05/03/2023]
Abstract
In mammals and plants, cytosine DNA methylation is essential for the epigenetic repression of transposable elements and foreign DNA. In plants, DNA methylation is guided by small interfering RNAs (siRNAs) in a self-reinforcing cycle termed RNA-directed DNA methylation (RdDM). RdDM requires the specialized RNA polymerase V (Pol V), and the key unanswered question is how Pol V is first recruited to new target sites without pre-existing DNA methylation. We find that Pol V follows and is dependent on the recruitment of an AGO4-clade ARGONAUTE protein, and any siRNA can guide the ARGONAUTE protein to the new target locus independent of pre-existing DNA methylation. These findings reject long-standing models of RdDM initiation and instead demonstrate that siRNA-guided ARGONAUTE targeting is necessary, sufficient and first to target Pol V recruitment and trigger the cycle of RdDM at a transcribed target locus, thereby establishing epigenetic silencing.
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Affiliation(s)
- Meredith J Sigman
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - Kaushik Panda
- Donald Danforth Plant Science Center, St. Louis, MO, USA
| | - Rachel Kirchner
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
- Medical Scientist Training Program, University of Wisconsin, Madison, WI, USA
| | | | - Hayden Payne
- Donald Danforth Plant Science Center, St. Louis, MO, USA
- Graduate Program in the School of Plant Sciences, University of Arizona, Tucson, AZ, USA
| | - John Reddy Peasari
- Donald Danforth Plant Science Center, St. Louis, MO, USA
- Bioinformatics and Computational Biology Program, Saint Louis University, St. Louis, MO, USA
| | - Aman Y Husbands
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
| | - R Keith Slotkin
- Donald Danforth Plant Science Center, St. Louis, MO, USA.
- Division of Biological Sciences, University of Missouri, Columbia, MO, USA.
| | - Andrea D McCue
- Department of Molecular Genetics, The Ohio State University, Columbus, OH, USA
- Donald Danforth Plant Science Center, St. Louis, MO, USA
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Yang P, Havecker E, Bauer M, Diehl C, Hendrix B, Hoffer P, Boyle T, Bradley J, Caruano-Yzermans A, Deikman J. Beyond identity: Understanding the contribution of the 5' nucleotide of the antisense strand to RNAi activity. PLoS One 2021; 16:e0256863. [PMID: 34492058 PMCID: PMC8423273 DOI: 10.1371/journal.pone.0256863] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 08/18/2021] [Indexed: 11/19/2022] Open
Abstract
In both the pharmaceutical and agricultural fields, RNA-based products have capitalized upon the mechanism of RNA interference for targeted reduction of gene expression to improve phenotypes and traits. Reduction in gene expression by RNAi is the result of a small interfering RNA (siRNA) molecule binding to an ARGONAUTE (AGO) protein and directing the effector complex to a homologous region of a target gene's mRNA. siRNAs properties that govern RNA-AGO association have been studied in detail. The siRNA 5' nucleotide (nt) identity has been demonstrated in plants to be an important property responsible for directing association of endogenous small RNAs with different AGO effector proteins. However, it has not been investigated whether the 5' nt identity is an efficacious determinant for topically-applied chemically synthesized siRNAs. In this study, we employed a sandpaper abrasion method to study the silencing efficacies of topically-applied 21 base-pair siRNA duplexes. The MAGNESIUM CHELATASE and GREEN FLUORESCENT PROTEIN genes were selected as endogenous and transgenic gene targets, respectively, to assess the molecular and phenotypic effects of gene silencing. Collections of siRNA variants with different 5' nt identities and different pairing states between the 5' antisense nt and its match in the sense strand of the siRNA duplex were tested for their silencing efficacy. Our results suggest a flexibility in the 5' nt requirement for topically applied siRNA duplexes in planta and highlight the similarity of 5' thermodynamic rules governing topical siRNA efficacy across plants and animals.
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Affiliation(s)
- Peizhen Yang
- Bayer Crop Science, St. Louis, Missouri, United States of America
| | - Ericka Havecker
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Matthew Bauer
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - Carl Diehl
- Bayer Crop Science, St. Louis, Missouri, United States of America
| | - Bill Hendrix
- Bayer Crop Science, Woodland, California, United States of America
| | - Paul Hoffer
- Bayer Crop Science, Woodland, California, United States of America
| | - Timothy Boyle
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | - John Bradley
- Bayer Crop Science, Chesterfield, Missouri, United States of America
| | | | - Jill Deikman
- Bayer Crop Science, Woodland, California, United States of America
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Arabidopsis MORC proteins function in the efficient establishment of RNA directed DNA methylation. Nat Commun 2021; 12:4292. [PMID: 34257299 PMCID: PMC8277788 DOI: 10.1038/s41467-021-24553-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Accepted: 06/21/2021] [Indexed: 01/19/2023] Open
Abstract
The Microrchidia (MORC) family of ATPases are required for transposable element (TE) silencing and heterochromatin condensation in plants and animals, and C. elegans MORC-1 has been shown to topologically entrap and condense DNA. In Arabidopsis thaliana, mutation of MORCs has been shown to reactivate silent methylated genes and transposons and to decondense heterochromatic chromocenters, despite only minor changes in the maintenance of DNA methylation. Here we provide the first evidence localizing Arabidopsis MORC proteins to specific regions of chromatin and find that MORC4 and MORC7 are closely co-localized with sites of RNA-directed DNA methylation (RdDM). We further show that MORC7, when tethered to DNA by an artificial zinc finger, can facilitate the establishment of RdDM. Finally, we show that MORCs are required for the efficient RdDM mediated establishment of DNA methylation and silencing of a newly integrated FWA transgene, even though morc mutations have no effect on the maintenance of preexisting methylation at the endogenous FWA gene. We propose that MORCs function as a molecular tether in RdDM complexes to reinforce RdDM activity for methylation establishment. These findings have implications for MORC protein function in a variety of other eukaryotic organisms.
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Ariel FD, Manavella PA. When junk DNA turns functional: transposon-derived non-coding RNAs in plants. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:4132-4143. [PMID: 33606874 DOI: 10.1093/jxb/erab073] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 02/12/2021] [Indexed: 05/05/2023]
Abstract
Transposable elements (TEs) are major contributors to genome complexity in eukaryotes. TE mobilization may cause genome instability, although it can also drive genome diversity throughout evolution. TE transposition may influence the transcriptional activity of neighboring genes by modulating the epigenomic profile of the region or by altering the relative position of regulatory elements. Notably, TEs have emerged in the last few years as an important source of functional long and small non-coding RNAs. A plethora of small RNAs derived from TEs have been linked to the trans regulation of gene activity at the transcriptional and post-transcriptional levels. Furthermore, TE-derived long non-coding RNAs have been shown to modulate gene expression by interacting with protein partners, sequestering active small RNAs, and forming duplexes with DNA or other RNA molecules. In this review, we summarize our current knowledge of the functional and mechanistic paradigms of TE-derived long and small non-coding RNAs and discuss their role in plant development and evolution.
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Affiliation(s)
- Federico D Ariel
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina
| | - Pablo A Manavella
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina
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