1
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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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2
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Liu F, Tang J, Li T, Zhang Q. The microRNA miR482 regulates NBS-LRR genes in response to ALT1 infection in apple. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2024; 343:112078. [PMID: 38556113 DOI: 10.1016/j.plantsci.2024.112078] [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: 12/20/2023] [Revised: 02/01/2024] [Accepted: 03/28/2024] [Indexed: 04/02/2024]
Abstract
Plants are frequently attacked by a variety of pathogens and thus have evolved a series of defense mechanisms, one important mechanism is resistance gene (R gene)-mediated disease resistance, but its expression is tightly regulated. NBS-LRR genes are the largest gene family of R genes. microRNAs (miRNAs) target to a number of NBS-LRR genes and trigger the production of phased small interfering RNAs (phasiRNAs) from these transcripts. phasiRNAs cis or trans regulate NBS-LRR genes, which can result in the repression of R gene expression. In this study, we screened for upregulated miR482 in the susceptible apple cultivar 'Golden Delicious' (GD) after inoculation with the fungal pathogen Alternaria alternata f. sp. mali (ALT1). Additionally, through combined degradome sequencing, we identified a gene targeted by miR482, named MdTNL1, a gene encoding a TIR-NBS-LRR (Toll/interleukin1 receptor-nucleotide binding site-leucine-rich repeat) protein. This gene exhibited a significant down-regulation post ALT1 inoculation, suggesting an impact on gene expression mediated by miRNA regulation. miR482 could cleave MdTNL1 and generate phasiRNAs at the cleavage site. We found that overexpression of miR482 inhibited the expression of MdTNL1 and thus reduced the disease resistance of GD, while silencing of miR482 increased the expression of MdTNL1 and thus improved the disease resistance of GD. This work elucidates key mechanisms underlying the immune response to Alternaria infection in apple. Identification of the resistance genes involved will enable molecular breeding for prevention and control of Alternaria leaf spot disease in this important fruit crop.
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Affiliation(s)
- Feiyu Liu
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193 China
| | - Jinqi Tang
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193 China
| | - Tianzhong Li
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193 China
| | - Qiulei Zhang
- Laboratory of Fruit Cell and Molecular Breeding, China Agricultural University, Beijing, 100193 China.
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3
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Tang J, Lei D, Yang J, Chen S, Wang X, Huang X, Zhang S, Cai Z, Zhu S, Wan J, Jia G. OsALKBH9-mediated m 6A demethylation regulates tapetal PCD and pollen exine accumulation in rice. PLANT BIOTECHNOLOGY JOURNAL 2024. [PMID: 38634166 DOI: 10.1111/pbi.14354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 02/24/2024] [Accepted: 03/30/2024] [Indexed: 04/19/2024]
Abstract
The N6-methyladenosine (m6A) mRNA modification is crucial for plant development and stress responses. In rice, the male sterility resulting from the deficiency of OsFIP37, a core component of m6A methyltransferase complex, emphasizes the significant role of m6A in male fertility. m6A is reversible and can be removed by m6A demethylases. However, whether mRNA m6A demethylase regulates male fertility in rice has remained unknown. Here, we identify the mRNA m6A demethylase OsALKBH9 and demonstrate its involvement in male fertility regulation. Knockout of OsALKBH9 causes male sterility, dependent on its m6A demethylation activity. Cytological analysis reveals defective tapetal programmed cell death (PCD) and excessive accumulation of microspores exine in Osalkbh9-1. Transcriptome analysis of anthers shows up-regulation of genes involved in tapetum development, sporopollenin synthesis, and transport pathways in Osalkbh9-1. Additionally, we demonstrate that OsALKBH9 demethylates the m6A modification in TDR and GAMYB transcripts, which affects the stability of these mRNAs and ultimately leads to excessive accumulation of pollen exine. Our findings highlight the precise control of mRNA m6A modification and reveal the pivotal roles played by OsALKBH9-mediated m6A demethylation in tapetal PCD and pollen exine accumulation in rice.
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Affiliation(s)
- Jun Tang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Dekun Lei
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Junbo Yang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
- Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong, China
| | - Shuyan Chen
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Xueping Wang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Xiaoxin Huang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Shasha Zhang
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Zhihe Cai
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Shanshan Zhu
- Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jianmin Wan
- National Key Facility for Crop Gene Resources and Genetic Improvement, Institute of Crop Sciences, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Guifang Jia
- Synthetic and Functional Biomolecules Center, Beijing National Laboratory for Molecular Sciences, Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
- Beijing Advanced Center of RNA Biology, Peking University, Beijing, China
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4
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Fan S, Zhang Y, Zhu S, Shen L. Plant RNA-binding proteins: Phase separation dynamics and functional mechanisms underlying plant development and stress responses. MOLECULAR PLANT 2024; 17:531-551. [PMID: 38419328 DOI: 10.1016/j.molp.2024.02.016] [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: 01/03/2024] [Revised: 02/19/2024] [Accepted: 02/26/2024] [Indexed: 03/02/2024]
Abstract
RNA-binding proteins (RBPs) accompany RNA from synthesis to decay, mediating every aspect of RNA metabolism and impacting diverse cellular and developmental processes in eukaryotes. Many RBPs undergo phase separation along with their bound RNA to form and function in dynamic membraneless biomolecular condensates for spatiotemporal coordination or regulation of RNA metabolism. Increasing evidence suggests that phase-separating RBPs with RNA-binding domains and intrinsically disordered regions play important roles in plant development and stress adaptation. Here, we summarize the current knowledge about how dynamic partitioning of RBPs into condensates controls plant development and enables sensing of experimental changes to confer growth plasticity under stress conditions, with a focus on the dynamics and functional mechanisms of RBP-rich nuclear condensates and cytoplasmic granules in mediating RNA metabolism. We also discuss roles of multiple factors, such as environmental signals, protein modifications, and N6-methyladenosine RNA methylation, in modulating the phase separation behaviors of RBPs, and highlight the prospects and challenges for future research on phase-separating RBPs in crops.
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Affiliation(s)
- Sheng Fan
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 1 Research Link, Singapore 117604, Singapore
| | - Yu Zhang
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 1 Research Link, Singapore 117604, Singapore
| | - Shaobo Zhu
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 1 Research Link, Singapore 117604, Singapore
| | - Lisha Shen
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, 1 Research Link, Singapore 117604, Singapore; Department of Biological Sciences, National University of Singapore, 14 Science Drive 4, Singapore 117543, Singapore.
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5
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Blagojevic A, Baldrich P, Schiaffini M, Lechner E, Baumberger N, Hammann P, Elmayan T, Garcia D, Vaucheret H, Meyers BC, Genschik P. Heat stress promotes Arabidopsis AGO1 phase separation and association with stress granule components. iScience 2024; 27:109151. [PMID: 38384836 PMCID: PMC10879784 DOI: 10.1016/j.isci.2024.109151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/17/2023] [Accepted: 02/01/2024] [Indexed: 02/23/2024] Open
Abstract
In Arabidopsis thaliana, ARGONAUTE1 (AGO1) plays a central role in microRNA (miRNA) and small interfering RNA (siRNA)-mediated silencing. AGO1 associates to the rough endoplasmic reticulum to conduct miRNA-mediated translational repression, mRNA cleavage, and biogenesis of phased siRNAs. Here, we show that a 37°C heat stress (HS) promotes AGO1 protein accumulation in cytosolic condensates where it colocalizes with components of siRNA bodies and of stress granules. AGO1 contains a prion-like domain in its poorly characterized N-terminal Poly-Q domain, which is sufficient to undergo phase separation independently of the presence of SGS3. HS only moderately affects the small RNA repertoire, the loading of AGO1 by miRNAs, and the signatures of target cleavage, suggesting that its localization in condensates protects AGO1 rather than promoting or impairing its activity in reprogramming gene expression during stress. Collectively, our work sheds new light on the impact of high temperature on a main effector of RNA silencing in plants.
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Affiliation(s)
- Aleksandar Blagojevic
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, 67084 Strasbourg, France
| | | | - Marlene Schiaffini
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, 67084 Strasbourg, France
| | - Esther Lechner
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, 67084 Strasbourg, France
| | - Nicolas Baumberger
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, 67084 Strasbourg, France
| | - Philippe Hammann
- Plateforme Protéomique Strasbourg Esplanade du CNRS, Université de Strasbourg, 67084 Strasbourg, France
| | - Taline Elmayan
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Damien Garcia
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, 67084 Strasbourg, France
| | - Hervé Vaucheret
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Blake C. Meyers
- Donald Danforth Plant Science Center, Saint Louis, MO 63132, USA
- Division of Plant Science and Technology, University of Missouri, Columbia, MO 65211, USA
| | - Pascal Genschik
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, 12, rue du Général Zimmer, 67084 Strasbourg, France
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6
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Li Q, Liu Y, Zhang X. Biomolecular condensates in plant RNA silencing: insights into formation, function, and stress responses. THE PLANT CELL 2024; 36:227-245. [PMID: 37772963 PMCID: PMC10827315 DOI: 10.1093/plcell/koad254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 09/14/2023] [Accepted: 09/14/2023] [Indexed: 09/30/2023]
Abstract
Biomolecular condensates are dynamic structures formed through diverse mechanisms, including liquid-liquid phase separation. These condensates have emerged as crucial regulators of cellular processes in eukaryotic cells, enabling the compartmentalization of specific biological reactions while allowing for dynamic exchange of molecules with the surrounding environment. RNA silencing, a conserved gene regulatory mechanism mediated by small RNAs (sRNAs), plays pivotal roles in various biological processes. Multiple types of biomolecular condensate, including dicing bodies, processing bodies, small interfering RNA bodies, and Cajal bodies, have been identified as key players in RNA silencing pathways. These biomolecular condensates provide spatial compartmentation for the biogenesis, loading, action, and turnover of small RNAs. Moreover, they actively respond to stresses, such as viral infections, and modulate RNA silencing activities during stress responses. This review summarizes recent advances in understanding of dicing bodies and other biomolecular condensates involved in RNA silencing. We explore their formation, roles in RNA silencing, and contributions to antiviral resistance responses. This comprehensive overview provides insights into the functional significance of biomolecular condensates in RNA silencing and expands our understanding of their roles in gene expression and stress responses in plants.
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Affiliation(s)
- Qi Li
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Yang Liu
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoming Zhang
- State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
- HainanYazhou Bay Seed Lab, Sanya, China
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7
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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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8
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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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9
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Pradhan M, Baldwin IT, Pandey SP. Argonaute7 (AGO7) optimizes arbuscular mycorrhizal fungal associations and enhances competitive growth in Nicotiana attenuata. THE NEW PHYTOLOGIST 2023; 240:382-398. [PMID: 37532924 DOI: 10.1111/nph.19155] [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: 03/23/2023] [Accepted: 07/02/2023] [Indexed: 08/04/2023]
Abstract
Plants interact with arbuscular mycorrhizal fungi (AMF) and in doing so, change transcript levels of many miRNAs and their targets. However, the identity of an Argonaute (AGO) that modulates this interaction remains unknown, including in Nicotiana attenuata. We examined how the silencing of NaAGO1/2/4/7/and 10 by RNAi influenced plant-competitive ability under low-P conditions when they interact with AMF. Furthermore, the roles of seven miRNAs, predicted to regulate signaling and phosphate homeostasis, were evaluated by transient overexpression. Only NaAGO7 silencing by RNAi (irAGO7) significantly reduced the competitive ability under P-limited conditions, without changes in leaf or root development, or juvenile-to-adult phase transitions. In plants growing competitively in the glasshouse, irAGO7 roots were over-colonized with AMF, but they accumulated significantly less phosphate and the expression of their AMF-specific transporters was deregulated. Furthermore, the AMF-induced miRNA levels were inversely regulated with the abundance of their target transcripts. miRNA overexpression consistently decreased plant fitness, with four of seven-tested miRNAs reducing mycorrhization rates, and two increasing mycorrhization rates. Overexpression of Na-miR473 and Na-miRNA-PN59 downregulated targets in GA, ethylene, and fatty acid metabolism pathways. We infer that AGO7 optimizes competitive ability and colonization by regulating miRNA levels and signaling pathways during a plant's interaction with AMF.
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Affiliation(s)
- Maitree Pradhan
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena, 07745, Germany
| | - Ian T Baldwin
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena, 07745, Germany
| | - Shree P Pandey
- Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, Jena, 07745, Germany
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10
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Solis-Miranda J, Chodasiewicz M, Skirycz A, Fernie AR, Moschou PN, Bozhkov PV, Gutierrez-Beltran E. Stress-related biomolecular condensates in plants. THE PLANT CELL 2023; 35:3187-3204. [PMID: 37162152 PMCID: PMC10473214 DOI: 10.1093/plcell/koad127] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 04/07/2023] [Accepted: 04/27/2023] [Indexed: 05/11/2023]
Abstract
Biomolecular condensates are membraneless organelle-like structures that can concentrate molecules and often form through liquid-liquid phase separation. Biomolecular condensate assembly is tightly regulated by developmental and environmental cues. Although research on biomolecular condensates has intensified in the past 10 years, our current understanding of the molecular mechanisms and components underlying their formation remains in its infancy, especially in plants. However, recent studies have shown that the formation of biomolecular condensates may be central to plant acclimation to stress conditions. Here, we describe the mechanism, regulation, and properties of stress-related condensates in plants, focusing on stress granules and processing bodies, 2 of the most well-characterized biomolecular condensates. In this regard, we showcase the proteomes of stress granules and processing bodies in an attempt to suggest methods for elucidating the composition and function of biomolecular condensates. Finally, we discuss how biomolecular condensates modulate stress responses and how they might be used as targets for biotechnological efforts to improve stress tolerance.
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Affiliation(s)
- Jorge Solis-Miranda
- Institutode Bioquimica Vegetal y Fotosintesis, Consejo Superior de Investigaciones Cientificas (CSIC)-Universidad de Sevilla, 41092 Sevilla, Spain
| | - Monika Chodasiewicz
- Biological and Environmental Science and Engineering Division, Center for Desert Agriculture, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia
| | | | - Alisdair R Fernie
- Max-Planck-Institute of Molecular Plant Physiology, 14476 Potsdam-Golm, Germany
| | - Panagiotis N Moschou
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007 Uppsala, Sweden
- Department of Biology, University of Crete, Heraklion 71409, Greece
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology-Hellas, Heraklion 70013, Greece
| | - Peter V Bozhkov
- Department of Molecular Sciences, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 75007 Uppsala, Sweden
| | - Emilio Gutierrez-Beltran
- Institutode Bioquimica Vegetal y Fotosintesis, Consejo Superior de Investigaciones Cientificas (CSIC)-Universidad de Sevilla, 41092 Sevilla, Spain
- Departamento de Bioquimica Vegetal y Biologia Molecular, Facultad de Biologia, Universidad de Sevilla, 41012 Sevilla, Spain
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11
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Han Y, Zhang X, Du R, Shan X, Xie D. The phase separation of SGS3 regulates antiviral immunity and fertility in Arabidopsis. SCIENCE CHINA. LIFE SCIENCES 2023; 66:1938-1941. [PMID: 36811803 DOI: 10.1007/s11427-022-2287-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 01/29/2023] [Indexed: 02/24/2023]
Affiliation(s)
- Yujie Han
- MOE Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiaolin Zhang
- MOE Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
- Shenzhen Branch of Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518124, China
| | - Ran Du
- Shenzhen Branch of Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, 518124, China
| | - Xiaoyi Shan
- MOE Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
| | - Daoxin Xie
- MOE Laboratory of Bioinformatics, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
- Peking University-Tsinghua University-National Institute of Biological Sciences Joint Graduate Program, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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12
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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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13
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Bazin J, Elvira-Matelot E, Blein T, Jauvion V, Bouteiller N, Cao J, Crespi MD, Vaucheret H. Synergistic action of the Arabidopsis spliceosome components PRP39a and SmD1b in promoting posttranscriptional transgene silencing. THE PLANT CELL 2023; 35:1917-1935. [PMID: 36970782 PMCID: PMC10226559 DOI: 10.1093/plcell/koad091] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 03/03/2023] [Accepted: 03/07/2023] [Indexed: 05/30/2023]
Abstract
Besides regulating splicing, the conserved spliceosome component SmD1 (Small nuclear ribonucleoprotein D1)b promotes posttranscriptional silencing of sense transgenes (S-PTGS [post-transcriptional genesilencing]). Here, we show that the conserved spliceosome component PRP39 (Pre-mRNA-processing factor 39)a also plays a role in S-PTGS in Arabidopsis thaliana. However, PRP39a and SmD1b actions appear distinct in both splicing and S-PTGS. Indeed, RNAseq-based analysis of expression level and alternative splicing in prp39a and smd1b mutants identified different sets of deregulated transcripts and noncoding RNAs. Moreover, double mutant analyses involving prp39a or smd1b and RNA quality control (RQC) mutants revealed distinct genetic interactions for SmD1b and PRP39a with nuclear RQC machineries, suggesting nonredundant roles in the RQC/PTGS interplay. Supporting this hypothesis, a prp39a smd1b double mutant exhibited enhanced suppression of S-PTGS compared to the single mutants. Because the prp39a and smd1b mutants (i) showed no major changes in the expression of PTGS or RQC components or in small RNA production and (ii) do not alter PTGS triggered by inverted-repeat transgenes directly producing dsRNA (IR-PTGS), PRP39a, and SmD1b appear to synergistically promote a step specific to S-PTGS. We propose that, independently from their specific roles in splicing, PRP39a and SmD1b limit 3'-to-5' and/or 5'-to-3' degradation of transgene-derived aberrant RNAs in the nucleus, thus favoring the export of aberrant RNAs to the cytoplasm where their conversion into double-stranded RNA (dsRNA) initiates S-PTGS.
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Affiliation(s)
- Jérémie Bazin
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRAE, Universités Paris-Sud, Evry, Paris-Diderot, Sorbonne Paris-Cité, Paris-Saclay, Bâtiment 630, 91405 Orsay, France
| | - Emilie Elvira-Matelot
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Thomas Blein
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRAE, Universités Paris-Sud, Evry, Paris-Diderot, Sorbonne Paris-Cité, Paris-Saclay, Bâtiment 630, 91405 Orsay, France
| | - Vincent Jauvion
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Nathalie Bouteiller
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
| | - Jun Cao
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany
| | - Martin D Crespi
- Institute of Plant Sciences Paris-Saclay (IPS2), CNRS, INRAE, Universités Paris-Sud, Evry, Paris-Diderot, Sorbonne Paris-Cité, Paris-Saclay, Bâtiment 630, 91405 Orsay, France
| | - Hervé Vaucheret
- Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin (IJPB), 78000 Versailles, France
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14
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Phase separation of SGS3 drives siRNA body formation and promotes endogenous gene silencing. Cell Rep 2023; 42:111985. [PMID: 36640363 DOI: 10.1016/j.celrep.2022.111985] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 10/26/2022] [Accepted: 12/23/2022] [Indexed: 01/11/2023] Open
Abstract
The generation of small interfering RNA (siRNA) involves many RNA processing components, including SUPPRESSOR OF GENE SILENCING 3 (SGS3), RNA-DEPENDENT RNA POLYMERASE 6 (RDR6), and DICER-LIKE proteins (DCLs). Nonetheless, how these components are coordinated to produce siRNAs is unclear. Here, we show that SGS3 forms condensates via phase separation in vivo and in vitro. SGS3 interacts with RDR6 and drives it to form siRNA bodies in cytoplasm, which is promoted by SGS3-targeted RNAs. Disrupting SGS3 phase separation abrogates siRNA body assembly and siRNA biogenesis, whereas coexpression of SGS3 and RDR6 induces siRNA body formation in tobacco and yeast cells. Dysfunction in translation and mRNA decay increases the number of siRNA bodies, whereas DCL2/4 mutations enhance their size. Purification of SGS3 condensates identifies numerous RNA-binding proteins and siRNA processing components. Together, our findings reveal that SGS3 phase separation-mediated formation of siRNA bodies is essential for siRNA production and gene silencing.
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15
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Sehki H, Yu A, Elmayan T, Vaucheret H. TYMV and TRV infect Arabidopsis thaliana by expressing weak suppressors of RNA silencing and inducing host RNASE THREE LIKE1. PLoS Pathog 2023; 19:e1010482. [PMID: 36696453 PMCID: PMC9901757 DOI: 10.1371/journal.ppat.1010482] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2022] [Revised: 02/06/2023] [Accepted: 01/10/2023] [Indexed: 01/26/2023] Open
Abstract
Post-Transcriptional Gene Silencing (PTGS) is a defense mechanism that targets invading nucleic acids of endogenous (transposons) or exogenous (pathogens, transgenes) origins. During plant infection by viruses, virus-derived primary siRNAs target viral RNAs, resulting in both destruction of single-stranded viral RNAs (execution step) and production of secondary siRNAs (amplification step), which maximizes the plant defense. As a counter-defense, viruses express proteins referred to as Viral Suppressor of RNA silencing (VSR). Some viruses express VSRs that totally inhibit PTGS, whereas other viruses express VSRs that have limited effect. Here we show that infection with the Turnip yellow mosaic virus (TYMV) is enhanced in Arabidopsis ago1, ago2 and dcl4 mutants, which are impaired in the execution of PTGS, but not in dcl2, rdr1 and rdr6 mutants, which are impaired in the amplification of PTGS. Consistently, we show that the TYMV VSR P69 localizes in siRNA-bodies, which are the site of production of secondary siRNAs, and limits PTGS amplification. Moreover, TYMV induces the production of the host enzyme RNASE THREE-LIKE 1 (RTL1) to further reduce siRNA accumulation. Infection with the Tobacco rattle virus (TRV), which also encodes a VSR limiting PTGS amplification, induces RTL1 as well to reduce siRNA accumulation and promote infection. Together, these results suggest that RTL1 could be considered as a host susceptibility gene that is induced by viruses as a strategy to further limit the plant PTGS defense when VSRs are insufficient.
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Affiliation(s)
- Hayat Sehki
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
- Université Paris-Sud, Université Paris-Saclay, Orsay, France
| | - Agnès Yu
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Taline Elmayan
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
| | - Hervé Vaucheret
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, Versailles, France
- * E-mail:
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16
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Shi J, Jiang Q, Zhang S, Dai X, Wang F, Ma Y. MIR390 Is Involved in Regulating Anthracnose Resistance in Apple. PLANTS (BASEL, SWITZERLAND) 2022; 11:3299. [PMID: 36501336 PMCID: PMC9736487 DOI: 10.3390/plants11233299] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 11/18/2022] [Accepted: 11/22/2022] [Indexed: 06/17/2023]
Abstract
As an important cash crop in China, apple has a good flavor and is rich in nutrients. Fungal attacks have become a major obstacle in apple cultivation. Colletotrichum gloeosporioides is one of the most devastating fungal pathogens in apple. Thus, discovering resistance genes in response to C. gloeosporioides may aid in designing safer control strategies and facilitate the development of apple resistance breeding. A previous study reported that 'Hanfu' autotetraploid apple displayed higher C. gloeosporioides resistance than 'Hanfu' apple, and the expression level of mdm-MIR390b was significantly upregulated in autotetraploid plants compared to that in 'Hanfu' plants, as demonstrated by digital gene expression (DGE) analysis. It is still unclear, however, whether mdm-MIR390b regulates apple anthracnose resistance. Apple MIR390b was transformed into apple 'GL-3' plants to identify the functions of mdm-MIR390b in anthracnose resistance. C. gloeosporioides treatment analysis indicated that the overexpression of mdm-MIR390b reduced fungal damage to apple leaves and fruit. Physiology analysis showed that mdm-MIR390b increased C. gloeosporioides resistance by improving superoxide dismutase (SOD) and peroxidase (POD) activity to alleviate the damage caused by O2- and H2O2. Our results demonstrate that mdm-MIR390b can improve apple plants' anthracnose resistance.
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Affiliation(s)
- Jiajun Shi
- College of Horticulture, Shenyang Agricultural University, Shenyang 110866, China
| | - Qiu Jiang
- Liaoning Institute of Pomology, Xiongyue 115009, China
| | - Shuyuan Zhang
- College of Horticulture, Shenyang Agricultural University, Shenyang 110866, China
| | - Xinyu Dai
- College of Horticulture, Shenyang Agricultural University, Shenyang 110866, China
| | - Feng Wang
- College of Plant Protection, Shenyang Agricultural University, Shenyang 110866, China
| | - Yue Ma
- College of Horticulture, Shenyang Agricultural University, Shenyang 110866, China
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17
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Ecotype-specific blockage of tasiARF production by two different RNA viruses in Arabidopsis. PLoS One 2022; 17:e0275588. [PMID: 36197942 PMCID: PMC9534422 DOI: 10.1371/journal.pone.0275588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Accepted: 09/20/2022] [Indexed: 11/19/2022] Open
Abstract
Arabidopsis thaliana is one of the most studied model organisms of plant biology with hundreds of geographical variants called ecotypes. One might expect that this enormous genetic variety could result in differential response to pathogens. Indeed, we observed previously that the Bur ecotype develops much more severe symptoms (upward curling leaves and wavy leaf margins) upon infection with two positive-strand RNA viruses of different families (turnip vein-clearing virus, TVCV, and turnip mosaic virus, TuMV). To find the genes potentially responsible for the ecotype-specific response, we performed a differential expression analysis of the mRNA and sRNA pools of TVCV and TuMV-infected Bur and Col plants along with the corresponding mock controls. We focused on the genes and sRNAs that showed an induced or reduced expression selectively in the Bur virus samples in both virus series. We found that the two ecotypes respond to the viral infection differently, yet both viruses selectively block the production of the TAS3-derived small RNA specimen called tasiARF only in the virus-infected Bur plants. The tasiARF normally forms a gradient through the adaxial and abaxial parts of the leaf (being more abundant in the adaxial part) and post-transcriptionally regulates ARF4, a major leaf polarity determinant in plants. The lack of tasiARF-mediated silencing could lead to an ectopically expressed ARF4 in the adaxial part of the leaf where the misregulation of auxin-dependent signaling would result in an irregular growth of the leaf blade manifesting as upward curling leaf and wavy leaf margin. QTL mapping using Recombinant Inbred Lines (RILs) suggests that the observed symptoms are the result of a multigenic interaction that allows the symptoms to develop only in the Bur ecotype. The particular nature of genetic differences leading to the ecotype-specific symptoms remains obscure and needs further study.
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18
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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: 16] [Impact Index Per Article: 8.0] [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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19
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Ruf A, Oberkofler L, Robatzek S, Weiberg A. Spotlight on plant RNA-containing extracellular vesicles. CURRENT OPINION IN PLANT BIOLOGY 2022; 69:102272. [PMID: 35964451 DOI: 10.1016/j.pbi.2022.102272] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/29/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Extracellular vesicles (EVs) carrying RNA have attracted growing attention in plant cell biology. For a long time, EV release or uptake through the rigid plant cell wall was considered to be impossible and RNA outside cells to be unstable. Identified EV biomarkers have brought new insights into functional roles of EVs to transport their RNA cargo for systemic spread in plants and into plant-invading pathogens. RNA-binding proteins supposedly take over key functions in EV-mediated RNA secretion and transport, but the mechanisms of RNA sorting and EV translocation through the plant cell wall and plasma membrane are not understood. Characterizing the molecular players and the cellular mechanisms of plant RNA-containing EVs will create new knowledge in cell-to-cell and inter-organismal communication.
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Affiliation(s)
- Alessa Ruf
- LMU Munich Biocenter, Großhaderner Straße 4, 82152 Planegg-Martinsried, DE, Germany
| | - Lorenz Oberkofler
- LMU Munich Biocenter, Großhaderner Straße 4, 82152 Planegg-Martinsried, DE, Germany
| | - Silke Robatzek
- LMU Munich Biocenter, Großhaderner Straße 4, 82152 Planegg-Martinsried, DE, Germany
| | - Arne Weiberg
- LMU Munich Biocenter, Großhaderner Straße 4, 82152 Planegg-Martinsried, DE, Germany.
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20
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Li H, You C, Yoshikawa M, Yang X, Gu H, Li C, Cui J, Chen X, Ye N, Zhang J, Wang G. A spontaneous thermo-sensitive female sterility mutation in rice enables fully mechanized hybrid breeding. Cell Res 2022; 32:931-945. [PMID: 36068348 PMCID: PMC9525692 DOI: 10.1038/s41422-022-00711-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 08/08/2022] [Indexed: 11/08/2022] Open
Abstract
Male sterility enables hybrid crop breeding to increase yields and has been extensively studied. But thermo-sensitive female sterility, which is an ideal property that may enable full mechanization in hybrid rice breeding, has rarely been investigated due to the absence of such germplasm. Here we identify the spontaneous thermo-sensitive female sterility 1 (tfs1) mutation that confers complete sterility under regular/high temperature and partial fertility under low temperature as a point mutation in ARGONAUTE7 (AGO7). AGO7 associates with miR390 to form an RNA-Induced Silencing Complex (RISC), which triggers the biogenesis of small interfering RNAs (siRNAs) from TRANS-ACTING3 (TAS3) loci by recruiting SUPPRESSOR OF GENE SILENCING (SGS3) and RNA-DEPENDENT RNA POLYMERASE6 (RDR6) to TAS3 transcripts. These siRNAs are known as tasiR-ARFs as they act in trans to repress auxin response factor genes. The mutant TFS1 (mTFS1) protein is compromised in its ability to load the miR390/miR390* duplex and eject miR390* during RISC formation. Furthermore, tasiR-ARF levels are reduced in tfs1 due to the deficiency in RDR6 but not SGS3 recruitment by mTFS1 RISC under regular/high temperature, while low temperature partially restores mTFS1 function in RDR6 recruitment and tasiR-ARF biogenesis. A miR390 mutant also exhibits female sterility, suggesting that female fertility is controlled by the miR390-AGO7 module. Notably, the tfs1 allele introduced into various elite rice cultivars endows thermo-sensitive female sterility. Moreover, field trials confirm the utility of tfs1 as a restorer line in fully mechanized hybrid rice breeding.
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Affiliation(s)
- Haoxuan Li
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Agriculture, Hunan Agricultural University, Changsha, Hunan, China
| | - Chenjiang You
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, USA
| | - Manabu Yoshikawa
- Division of Plant and Microbial Sciences, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, 2-1-2 Kannondai Tsukuba, Ibaraki, Japan
| | - Xiaoyu Yang
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, China
- College of Horticulture Science and Engineering, Shandong Agricultural University, Taian, Shandong, China
| | - Haiyong Gu
- The Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, China
| | - Chuanguo Li
- The Rice Research Institute, Guangdong Academy of Agricultural Sciences, Guangzhou, Guangdong, China
| | - Jie Cui
- Guangdong Provincial Key Laboratory for Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, Guangdong, China
| | - Xuemei Chen
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, USA.
| | - Nenghui Ye
- Southern Regional Collaborative Innovation Center for Grain and Oil Crops in China, College of Agriculture, Hunan Agricultural University, Changsha, Hunan, China.
| | - Jianhua Zhang
- Department of Biology, Hong Kong Baptist University, Hong Kong, China.
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China.
| | - Guanqun Wang
- Department of Biology, Hong Kong Baptist University, Hong Kong, China.
- School of Life Sciences and State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China.
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21
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Hoffmann G, Mahboubi A, Bente H, Garcia D, Hanson J, Hafrén A. Arabidopsis RNA processing body components LSM1 and DCP5 aid in the evasion of translational repression during Cauliflower mosaic virus infection. THE PLANT CELL 2022; 34:3128-3147. [PMID: 35511183 PMCID: PMC9338796 DOI: 10.1093/plcell/koac132] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Accepted: 04/24/2022] [Indexed: 06/14/2023]
Abstract
Viral infections impose extraordinary RNA stress, triggering cellular RNA surveillance pathways such as RNA decapping, nonsense-mediated decay, and RNA silencing. Viruses need to maneuver among these pathways to establish infection and succeed in producing high amounts of viral proteins. Processing bodies (PBs) are integral to RNA triage in eukaryotic cells, with several distinct RNA quality control pathways converging for selective RNA regulation. In this study, we investigated the role of Arabidopsis thaliana PBs during Cauliflower mosaic virus (CaMV) infection. We found that several PB components are co-opted into viral factories that support virus multiplication. This pro-viral role was not associated with RNA decay pathways but instead, we established that PB components are helpers in viral RNA translation. While CaMV is normally resilient to RNA silencing, dysfunctions in PB components expose the virus to this pathway, which is similar to previous observations for transgenes. Transgenes, however, undergo RNA quality control-dependent RNA degradation and transcriptional silencing, whereas CaMV RNA remains stable but becomes translationally repressed through decreased ribosome association, revealing a unique dependence among PBs, RNA silencing, and translational repression. Together, our study shows that PB components are co-opted by the virus to maintain efficient translation, a mechanism not associated with canonical PB functions.
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Affiliation(s)
- Gesa Hoffmann
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala 75007, Sweden
- Linnean Center for Plant Biology, Uppsala 75007, Sweden
| | - Amir Mahboubi
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
| | - Heinrich Bente
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences, Uppsala 75007, Sweden
- Linnean Center for Plant Biology, Uppsala 75007, Sweden
| | - Damien Garcia
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Johannes Hanson
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, Umeå, Sweden
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22
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Chodasiewicz M, Jang JC, Gutierrez-Beltran E. Editorial: Biology of Stress Granules in Plants. FRONTIERS IN PLANT SCIENCE 2022; 13:938654. [PMID: 35755667 PMCID: PMC9218739 DOI: 10.3389/fpls.2022.938654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Affiliation(s)
- Monika Chodasiewicz
- Center for Desert Agriculture, Biological and Environmental Science and Engineering Division (BESE), King Abdullah University of Science and Technology (KAUST), Thuwal, Saudi Arabia
| | - J. C. Jang
- Department of Horticulture and Crop Science and Department of Molecular Genetics, Center for Applied Plant Sciences and Center for RNA Biology, The Ohio State University, Columbus, OH, United States
| | - Emilio Gutierrez-Beltran
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla and Consejo Superior de Investigaciones Científicas (CSIC), Seville, Spain
- Departamento de Bioquímica Vegetal y Biología Molecular, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
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23
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Chen X, Rechavi O. Plant and animal small RNA communications between cells and organisms. Nat Rev Mol Cell Biol 2022; 23:185-203. [PMID: 34707241 PMCID: PMC9208737 DOI: 10.1038/s41580-021-00425-y] [Citation(s) in RCA: 69] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/24/2021] [Indexed: 01/09/2023]
Abstract
Since the discovery of eukaryotic small RNAs as the main effectors of RNA interference in the late 1990s, diverse types of endogenous small RNAs have been characterized, most notably microRNAs, small interfering RNAs (siRNAs) and PIWI-interacting RNAs (piRNAs). These small RNAs associate with Argonaute proteins and, through sequence-specific gene regulation, affect almost every major biological process. Intriguing features of small RNAs, such as their mechanisms of amplification, rapid evolution and non-cell-autonomous function, bestow upon them the capacity to function as agents of intercellular communications in development, reproduction and immunity, and even in transgenerational inheritance. Although there are many types of extracellular small RNAs, and despite decades of research, the capacity of these molecules to transmit signals between cells and between organisms is still highly controversial. In this Review, we discuss evidence from different plants and animals that small RNAs can act in a non-cell-autonomous manner and even exchange information between species. We also discuss mechanistic insights into small RNA communications, such as the nature of the mobile agents, small RNA signal amplification during transit, signal perception and small RNA activity at the destination.
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Affiliation(s)
- Xuemei Chen
- Department of Botany and Plant Sciences, Institute for Integrative Genome Biology, University of California, Riverside, CA, USA.
| | - Oded Rechavi
- Department of Neurobiology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel. .,Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel.
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24
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Jullien PE, Schröder JA, Bonnet DMV, Pumplin N, Voinnet O. Asymmetric expression of Argonautes in reproductive tissues. PLANT PHYSIOLOGY 2022; 188:38-43. [PMID: 34687292 PMCID: PMC8774725 DOI: 10.1093/plphys/kiab474] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 09/13/2021] [Indexed: 06/01/2023]
Abstract
The Arabidopsis genome encodes ten Argonautes proteins showing distinct expression pattern as well as intracellular localisation during sexual reproduction.
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Affiliation(s)
- P E Jullien
- Institute of Plant Sciences, University of Bern, 3012 Bern, Switzerland
- Institute of Molecular Plant Biology—Swiss Federal Institute of Technology Zurich (ETH‐Zurich), 8092 Zurich, Switzerland
| | - J A Schröder
- Institute of Plant Sciences, University of Bern, 3012 Bern, Switzerland
| | - D M V Bonnet
- Institute of Plant Sciences, University of Bern, 3012 Bern, Switzerland
| | - N Pumplin
- Institute of Molecular Plant Biology—Swiss Federal Institute of Technology Zurich (ETH‐Zurich), 8092 Zurich, Switzerland
| | - O Voinnet
- Institute of Molecular Plant Biology—Swiss Federal Institute of Technology Zurich (ETH‐Zurich), 8092 Zurich, Switzerland
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25
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Lei Z, Wang L, Kim EY, Cho J. Phase separation of chromatin and small RNA pathways in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 108:1256-1265. [PMID: 34585805 DOI: 10.1111/tpj.15517] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Revised: 09/18/2021] [Accepted: 09/25/2021] [Indexed: 06/13/2023]
Abstract
Gene expression can be modulated by epigenetic mechanisms, including chromatin modifications and small regulatory RNAs. These pathways are unevenly distributed within a cell and usually take place in specific intracellular regions. Unfortunately, the fundamental driving force and biological relevance of such spatial differentiation is largely unknown. Liquid-liquid phase separation (LLPS) is a natural propensity of demixing liquid phases and has been recently suggested to mediate the formation of biomolecular condensates that are relevant to diverse cellular processes. LLPS provides a mechanistic explanation for the self-assembly of subcellular structures by which the efficiency and specificity of certain cellular reactions are achieved. In plants, LLPS has been observed for several key factors in the chromatin and small RNA pathways. For example, the formation of facultative and obligate heterochromatin involves the LLPS of multiple relevant factors. In addition, phase separation is observed in a set of proteins acting in microRNA biogenesis and the small interfering RNA pathway. In this Focused Review, we highlight and discuss the recent findings regarding phase separation in the epigenetic mechanisms of plants.
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Affiliation(s)
- Zhen Lei
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Ling Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Eun Yu Kim
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
| | - Jungnam Cho
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, 200032, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
- CAS-JIC Centre of Excellence for Plant and Microbial Science (CEPAMS), Chinese Academy of Sciences, Shanghai, 200032, China
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26
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Field S, Conner WC, Roberts DM. Arabidopsis CALMODULIN-LIKE 38 Regulates Hypoxia-Induced Autophagy of SUPPRESSOR OF GENE SILENCING 3 Bodies. FRONTIERS IN PLANT SCIENCE 2021; 12:722940. [PMID: 34567037 PMCID: PMC8456008 DOI: 10.3389/fpls.2021.722940] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/09/2021] [Indexed: 05/23/2023]
Abstract
During the energy crisis associated with submergence stress, plants restrict mRNA translation and rapidly accumulate stress granules that act as storage hubs for arrested mRNA complexes. One of the proteins associated with hypoxia-induced stress granules in Arabidopsis thaliana is the calcium-sensor protein CALMODULIN-LIKE 38 (CML38). Here, we show that SUPPRESSOR OF GENE SILENCING 3 (SGS3) is a CML38-binding protein, and that SGS3 and CML38 co-localize within hypoxia-induced RNA stress granule-like structures. Hypoxia-induced SGS3 granules are subject to turnover by autophagy, and this requires both CML38 as well as the AAA+-ATPase CELL DIVISION CYCLE 48A (CDC48A). CML38 also interacts directly with CDC48A, and CML38 recruits CDC48A to CML38 granules in planta. Together, this work demonstrates that SGS3 associates with stress granule-like structures during hypoxia stress that are subject to degradation by CML38 and CDC48-dependent autophagy. Further, the work identifies direct regulatory targets for the hypoxia calcium-sensor CML38, and suggest that CML38 association with stress granules and associated regulation of autophagy may be part of the RNA regulatory program during hypoxia stress.
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27
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Sakurai Y, Baeg K, Lam AYW, Shoji K, Tomari Y, Iwakawa HO. Cell-free reconstitution reveals the molecular mechanisms for the initiation of secondary siRNA biogenesis in plants. Proc Natl Acad Sci U S A 2021; 118:e2102889118. [PMID: 34330830 PMCID: PMC8346886 DOI: 10.1073/pnas.2102889118] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Secondary small interfering RNA (siRNA) production, triggered by primary small RNA targeting, is critical for proper development and antiviral defense in many organisms. RNA-dependent RNA polymerase (RDR) is a key factor in this pathway. However, how RDR specifically converts the targets of primary small RNAs into double-stranded RNA (dsRNA) intermediates remains unclear. Here, we develop an in vitro system that allows for dissection of the molecular mechanisms underlying the production of trans-acting siRNAs, a class of plant secondary siRNAs that play roles in organ development and stress responses. We find that a combination of the dsRNA-binding protein, SUPPRESSOR OF GENE SILENCING3; the putative nuclear RNA export factor, SILENCING DEFECTIVE5, primary small RNA, and Argonaute is required for physical recruitment of RDR6 to target RNAs. dsRNA synthesis by RDR6 is greatly enhanced by the removal of the poly(A) tail, which can be achieved by the cleavage at a second small RNA-binding site bearing appropriate mismatches. Importantly, when the complementarity of the base pairing at the second target site is too strong, the small RNA-Argonaute complex remains at the cleavage site, thereby blocking the initiation of dsRNA synthesis by RDR6. Our data highlight the light and dark sides of double small RNA targeting in the secondary siRNA biogenesis.
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Affiliation(s)
- Yuriki Sakurai
- 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
| | - Kyungmin Baeg
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Andy Y W Lam
- 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
| | - 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
- Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan;
- Precursory Research for Embryonic Science and Technology (PRESTO), Japan Science and Technology Agency (JST), Saitama 332-0012, Japan
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28
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Brioudes F, Jay F, Sarazin A, Grentzinger T, Devers EA, Voinnet O. HASTY, the Arabidopsis EXPORTIN5 ortholog, regulates cell-to-cell and vascular microRNA movement. EMBO J 2021; 40:e107455. [PMID: 34152631 PMCID: PMC8327949 DOI: 10.15252/embj.2020107455] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Revised: 05/04/2021] [Accepted: 05/07/2021] [Indexed: 01/04/2023] Open
Abstract
Plant microRNAs (miRNAs) guide cytosolic post-transcriptional gene silencing of sequence-complementary transcripts within the producing cells, as well as in distant cells and tissues. Here, we used an artificial miRNA-based system (amiRSUL) in Arabidopsis thaliana to explore the still elusive mechanisms of inter-cellular miRNA movement via forward genetics. This screen identified many mutant alleles of HASTY (HST), the ortholog of mammalian EXPORTIN5 (XPO5) with a recently reported role in miRNA biogenesis in Arabidopsis. In both epidermis-peeling and grafting assays, amiRSUL levels were reduced much more substantially in miRNA-recipient tissues than in silencing-emitting tissues. We ascribe this effect to HST controlling cell-to-cell and phloem-mediated movement of the processed amiRSUL, in addition to regulating its biogenesis. While HST is not required for the movement of free GFP or siRNAs, its cell-autonomous expression in amiRSUL-emitting tissues suffices to restore amiRSUL movement independently of its nucleo-cytosolic shuttling activity. By contrast, HST is dispensable for the movement and activity of amiRSUL within recipient tissues. Finally, HST enables movement of endogenous miRNAs that display mostly unaltered steady-state levels in hst mutant tissues. We discuss a role for HST as a hitherto unrecognized regulator of miRNA movement in relation to its recently assigned nuclear function at the nexus of MIRNA transcription and miRNA processing.
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Affiliation(s)
| | - Florence Jay
- Department of BiologyETH ZürichZürichSwitzerland
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29
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Yang X, Dong W, Ren W, Zhao Q, Wu F, He Y. Cytoplasmic HYL1 modulates miRNA-mediated translational repression. THE PLANT CELL 2021; 33:1980-1996. [PMID: 33764452 PMCID: PMC8290291 DOI: 10.1093/plcell/koab090] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Accepted: 03/19/2021] [Indexed: 05/05/2023]
Abstract
MicroRNAs (miRNAs) control various biological processes by repressing target mRNAs. In plants, miRNAs mediate target gene repression via both mRNA cleavage and translational repression. However, the mechanism underlying this translational repression is poorly understood. Here, we found that Arabidopsis thaliana HYPONASTIC LEAVES1 (HYL1), a core component of the miRNA processing machinery, regulates miRNA-mediated mRNA translation but not miRNA biogenesis when it localized in the cytoplasm. Cytoplasmic HYL1 localizes to the endoplasmic reticulum and associates with ARGONAUTE1 (AGO1) and ALTERED MERISTEM PROGRAM1. In the cytoplasm, HYL1 monitors the distribution of AGO1 onto polysomes, binds to the mRNAs of target genes, represses their translation, and partially rescues the phenotype of the hyl1 null mutant. This study uncovered another function of HYL1 and provides insight into the mechanism of plant gene regulation.
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Affiliation(s)
- Xi Yang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Weiguo Dong
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
- School of Biotechnology, East China University of Science and Technology, Shanghai 200237, China
| | - Wenqing Ren
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- University of the Chinese Academy of Sciences, Beijing 100049, China
| | - Qiuxia Zhao
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Feijie Wu
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Yuke He
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
- Author for correspondence:
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30
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Gong P, Tan H, Zhao S, Li H, Liu H, Ma Y, Zhang X, Rong J, Fu X, Lozano-Durán R, Li F, Zhou X. Geminiviruses encode additional small proteins with specific subcellular localizations and virulence function. Nat Commun 2021; 12:4278. [PMID: 34257307 PMCID: PMC8277811 DOI: 10.1038/s41467-021-24617-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 06/21/2021] [Indexed: 12/14/2022] Open
Abstract
Geminiviruses are plant viruses with limited coding capacity. Geminivirus-encoded proteins are traditionally identified by applying a 10-kDa arbitrary threshold; however, it is increasingly clear that small proteins play relevant roles in biological systems, which calls for the reconsideration of this criterion. Here, we show that geminiviral genomes contain additional ORFs. Using tomato yellow leaf curl virus, we demonstrate that some of these small ORFs are expressed during the infection, and that the encoded proteins display specific subcellular localizations. We prove that the largest of these additional ORFs, which we name V3, is required for full viral infection, and that the V3 protein localizes in the Golgi apparatus and functions as an RNA silencing suppressor. These results imply that the repertoire of geminiviral proteins can be expanded, and that getting a comprehensive overview of the molecular plant-geminivirus interactions will require the detailed study of small ORFs so far neglected.
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Affiliation(s)
- Pan Gong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Huang Tan
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Siwen Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hao Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Hui Liu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Yu Ma
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Xi Zhang
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Junjie Rong
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Xing Fu
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Rosa Lozano-Durán
- Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China.
- Department of Plant Biochemistry, Center for Plant Molecular Biology (ZMBP), Eberhard Karls University, Tübingen, Germany.
| | - Fangfang Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Xueping Zhou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China.
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China.
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31
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Iwakawa HO, Lam AYW, Mine A, Fujita T, Kiyokawa K, Yoshikawa M, Takeda A, Iwasaki S, Tomari Y. Ribosome stalling caused by the Argonaute-microRNA-SGS3 complex regulates the production of secondary siRNAs in plants. Cell Rep 2021; 35:109300. [PMID: 34192539 DOI: 10.1016/j.celrep.2021.109300] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 04/10/2021] [Accepted: 06/03/2021] [Indexed: 12/31/2022] Open
Abstract
The path of ribosomes on mRNAs can be impeded by various obstacles. One such example is halting of ribosome movement by microRNAs, but the exact mechanism and physiological role remain unclear. Here, we find that ribosome stalling caused by the Argonaute-microRNA-SGS3 complex regulates production of secondary small interfering RNAs (siRNAs) in plants. We show that the double-stranded RNA-binding protein SGS3 interacts directly with the 3' end of the microRNA in an Argonaute protein, resulting in ribosome stalling. Importantly, microRNA-mediated ribosome stalling correlates positively with efficient production of secondary siRNAs from target mRNAs. Our results illustrate a role of paused ribosomes in regulation of small RNA function that may have broad biological implications across the plant kingdom.
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Affiliation(s)
- Hiro-Oki Iwakawa
- Laboratory of RNA Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan; JST, PRESTO, Kawaguchi, Saitama 332-0012, Japan.
| | - Andy Y W Lam
- Laboratory of RNA Function, 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
| | - Akira Mine
- JST, PRESTO, Kawaguchi, Saitama 332-0012, Japan; Department of Biotechnology, Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Tomoya Fujita
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan; School of Life Science and Technology, Tokyo Institute of Technology, Midori-ku, Kanagawa 226-8503, Japan
| | - Kaori Kiyokawa
- Laboratory of RNA Function, Institute for Quantitative Biosciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan
| | - Manabu Yoshikawa
- Division of Crop Growth Mechanism, Research Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8518, Japan
| | - Atsushi Takeda
- Department of Biotechnology, Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan
| | - Shintaro Iwasaki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0032, Japan; RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Yukihide Tomari
- Laboratory of RNA Function, 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
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32
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Global Analysis of RNA-Dependent RNA Polymerase-Dependent Small RNAs Reveals New Substrates and Functions for These Proteins and SGS3 in Arabidopsis. Noncoding RNA 2021; 7:ncrna7020028. [PMID: 33925339 PMCID: PMC8167712 DOI: 10.3390/ncrna7020028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/19/2021] [Accepted: 04/20/2021] [Indexed: 12/29/2022] Open
Abstract
RNA silencing pathways control eukaryotic gene expression transcriptionally or posttranscriptionally in a sequence-specific manner. In RNA silencing, the production of double-stranded RNA (dsRNA) gives rise to various classes of 20-24 nucleotide (nt) small RNAs (smRNAs). In Arabidopsis thaliana, smRNAs are often derived from long dsRNA molecules synthesized by one of the six genomically encoded RNA-dependent RNA Polymerase (RDR) proteins. However, the full complement of the RDR-dependent smRNAs and functions that these proteins and their RNA-binding cofactors play in plant RNA silencing has not been fully uncovered. To address this gap, we performed a global genomic analysis of all six RDRs and two of their cofactors to find new substrates for RDRs and targets of the resulting RDR-derived siRNAs to uncover new functions for these proteins in plants. Based on these analyses, we identified substrates for the three RDRγ clade proteins (RDR3-5), which had not been well-characterized previously. We also identified new substrates for the other three RDRs (RDR1, RDR2, and RDR6) as well as the RDR2 cofactor RNA-directed DNA methylation 12 (RDM12) and the RDR6 cofactor suppressor of gene silencing 3 (SGS3). These findings revealed that the target substrates of SGS3 are not limited to those solely utilized by RDR6, but that this protein seems to be a more general cofactor for the RDR family of proteins. Additionally, we found that RDR6 and SGS3 are involved in the production of smRNAs that target transcripts related to abiotic stresses, including water deprivation, salt stress, and ABA response, and as expected the levels of these mRNAs are increased in rdr6 and sgs3 mutant plants. Correspondingly, plants that lack these proteins (rdr6 and sgs3 mutants) are hypersensitive to ABA treatment, tolerant to high levels of PEG8000, and have a higher survival rate under salt treatment in comparison to wild-type plants. In total, our analyses have provided an extremely data-rich resource for uncovering new functions of RDR-dependent RNA silencing in plants, while also revealing a previously unexplored link between the RDR6/SGS3-dependent pathway and plant abiotic stress responses.
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33
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Kim EY, Wang L, Lei Z, Li H, Fan W, Cho J. Ribosome stalling and SGS3 phase separation prime the epigenetic silencing of transposons. NATURE PLANTS 2021; 7:303-309. [PMID: 33649597 DOI: 10.1038/s41477-021-00867-4] [Citation(s) in RCA: 43] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 02/01/2021] [Indexed: 05/20/2023]
Abstract
Transposable elements (TEs, transposons) are mobile DNAs that can cause fatal mutations1. To suppress their activity, host genomes deploy small interfering RNAs (siRNAs) that trigger and maintain their epigenetic silencing2,3. Whereas 24-nucleotide (nt) siRNAs mediate RNA-directed DNA methylation (RdDM) to reinforce the silent state of TEs3, activated or naive TEs give rise to 21- or 22-nt siRNAs by the RNA-DEPENDENT RNA POLYMERASE 6 (RDR6)-mediated pathway, triggering both RNAi and de novo DNA methylation4,5. This process, which is called RDR6-RdDM, is critical for the initiation of epigenetic silencing of active TEs; however, their specific recognition and the selective processing of siRNAs remain elusive. Here, we suggest that plant transposon RNAs undergo frequent ribosome stalling caused by their unfavourable codon usage. Ribosome stalling subsequently induces RNA truncation and localization to cytoplasmic siRNA bodies, both of which are essential prerequisites for RDR6 targeting6,7. In addition, SUPPRESSOR OF GENE SILENCING 3 (SGS3), the RDR6-interacting protein7, exhibits phase separation both in vitro and in vivo through its prion-like domains, implicating the role of liquid-liquid phase separation in siRNA body formation. Our study provides insight into the host recognition of active TEs, which is important for the maintenance of genome integrity.
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Affiliation(s)
- Eun Yu Kim
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Ling Wang
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Shanghai, China
| | - Zhen Lei
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Shanghai, China
| | - Hui Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Shanghai, China
| | - Wenwen Fan
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of Chinese Academy of Sciences, Shanghai, China
| | - Jungnam Cho
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences (CEMPS), Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China.
- University of Chinese Academy of Sciences, Shanghai, China.
- CAS-JIC Centre of Excellence for Plant and Microbial Science (CEPAMS), Chinese Academy of Sciences, Shanghai, China.
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34
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Dukowic-Schulze S, van der Linde K. Oxygen, secreted proteins and small RNAs: mobile elements that govern anther development. PLANT REPRODUCTION 2021; 34:1-19. [PMID: 33492519 PMCID: PMC7902584 DOI: 10.1007/s00497-020-00401-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 12/24/2020] [Indexed: 05/24/2023]
Abstract
Correct anther development is essential for male fertility and subsequently agricultural yield. Defects in anther development range from the early stage of stamen formation until the late stage of tapetum degeneration. In particular, the specification of the four distinct somatic layers and the inner sporogenous cells need perfect orchestration relying on precise cell-cell communication. Up to now, several signals, which coordinate the anther´s developmental program, have been identified. Among the known signals are phytohormones, environmental conditions sensed via glutaredoxins, several receptor-like kinases triggered by ligands like MAC1, and small RNAs such as miRNAs and the monocot-prevalent reproductive phasiRNAs. Rather than giving a full review on anther development, here we discuss anther development with an emphasis on mobile elements like ROS/oxygen, secreted proteins and small RNAs (only briefly touching on phytohormones), how they might act and interact, and what the future of this research area might reveal.
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Affiliation(s)
- Stefanie Dukowic-Schulze
- Department of Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany.
| | - Karina van der Linde
- Department of Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany.
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35
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Yang X, You C, Wang X, Gao L, Mo B, Liu L, Chen X. Widespread occurrence of microRNA-mediated target cleavage on membrane-bound polysomes. Genome Biol 2021; 22:15. [PMID: 33402203 PMCID: PMC7784310 DOI: 10.1186/s13059-020-02242-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 12/14/2020] [Indexed: 02/07/2023] Open
Abstract
Background Small RNAs (sRNAs) including microRNAs (miRNAs) and small interfering RNAs (siRNAs) serve as core players in gene silencing at transcriptional and post-transcriptional levels in plants, but their subcellular localization has not yet been well studied, thus limiting our mechanistic understanding of sRNA action. Results We investigate the cytoplasmic partitioning of sRNAs and their targets globally in maize (Zea mays, inbred line “B73”) and rice (Oryza sativa, cv. “Nipponbare”) by high-throughput sequencing of polysome-associated sRNAs and 3′ cleavage fragments, and find that both miRNAs and a subset of 21-nucleotide (nt)/22-nt siRNAs are enriched on membrane-bound polysomes (MBPs) relative to total polysomes (TPs) across different tissues. Most of the siRNAs are generated from transposable elements (TEs), and retrotransposons positively contributed to MBP overaccumulation of 22-nt TE-derived siRNAs (TE-siRNAs) as opposed to DNA transposons. Widespread occurrence of miRNA-mediated target cleavage is observed on MBPs, and a large proportion of these cleavage events are MBP-unique. Reproductive 21PHAS (21-nt phasiRNA-generating) and 24PHAS (24-nt phasiRNA-generating) precursors, which were commonly considered as noncoding RNAs, are bound by polysomes, and high-frequency cleavage of 21PHAS precursors by miR2118 and 24PHAS precursors by miR2275 is further detected on MBPs. Reproductive 21-nt phasiRNAs are enriched on MBPs as opposed to TPs, whereas 24-nt phasiRNAs are nearly completely devoid of polysome occupancy. Conclusions MBP overaccumulation is a conserved pattern for cytoplasmic partitioning of sRNAs, and endoplasmic reticulum (ER)-bound ribosomes function as an independent regulatory layer for miRNA-induced gene silencing and reproductive phasiRNA biosynthesis in maize and rice.
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Affiliation(s)
- Xiaoyu Yang
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Longhua Bioindustry and Innovation Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
| | - Chenjiang You
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - Xufeng Wang
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Longhua Bioindustry and Innovation Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China.,Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA
| | - Lei Gao
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Longhua Bioindustry and Innovation Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
| | - Beixin Mo
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Longhua Bioindustry and Innovation Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China
| | - Lin Liu
- Guangdong Provincial Key Laboratory for Plant Epigenetics, Longhua Bioindustry and Innovation Research Institute, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China.
| | - Xuemei Chen
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA, 92521, USA.
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36
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Liu Y, Teng C, Xia R, Meyers BC. PhasiRNAs in Plants: Their Biogenesis, Genic Sources, and Roles in Stress Responses, Development, and Reproduction. THE PLANT CELL 2020; 32:3059-3080. [PMID: 32817252 PMCID: PMC7534485 DOI: 10.1105/tpc.20.00335] [Citation(s) in RCA: 114] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 07/29/2020] [Accepted: 08/14/2020] [Indexed: 05/08/2023]
Abstract
Phased secondary small interfering RNAs (phasiRNAs) constitute a major category of small RNAs in plants, but most of their functions are still poorly defined. Some phasiRNAs, known as trans-acting siRNAs, are known to target complementary mRNAs for degradation and to function in development. However, the targets or biological roles of other phasiRNAs remain speculative. New insights into phasiRNA biogenesis, their conservation, and their variation across the flowering plants continue to emerge due to the increased availability of plant genomic sequences, deeper and more sophisticated sequencing approaches, and improvements in computational biology and biochemical/molecular/genetic analyses. In this review, we survey recent progress in phasiRNA biology, with a particular focus on two classes associated with male reproduction: 21-nucleotide (accumulate early in anther ontogeny) and 24-nucloetide (produced in somatic cells during meiosis) phasiRNAs. We describe phasiRNA biogenesis, function, and evolution and define the unanswered questions that represent topics for future research.
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Affiliation(s)
- Yuanlong Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, Guangdong 510640, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, Guangdong 510640, China
- College of Horticulture, South China Agricultural University, Guangzhou 510640, Guangdong, China
| | - Chong Teng
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Rui Xia
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, South China Agricultural University, Guangzhou, Guangdong 510640, China
- Guangdong Laboratory for Lingnan Modern Agriculture, South China Agricultural University, Guangzhou, Guangdong 510640, China
- College of Horticulture, South China Agricultural University, Guangzhou 510640, Guangdong, China
| | - Blake C Meyers
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
- Division of Plant Sciences, University of Missouri-Columbia, Columbia, Missouri 65211
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de Felippes FF, Waterhouse PM. The Whys and Wherefores of Transitivity in Plants. FRONTIERS IN PLANT SCIENCE 2020; 11:579376. [PMID: 32983223 PMCID: PMC7488869 DOI: 10.3389/fpls.2020.579376] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Accepted: 08/14/2020] [Indexed: 05/05/2023]
Abstract
Transitivity in plants is a mechanism that produces secondary small interfering RNAs (siRNAs) from a transcript targeted by primary small RNAs (sRNAs). It expands the silencing signal to additional sequences of the transcript. The process requires RNA-dependent RNA polymerases (RDRs), which convert single-stranded RNA targets into a double-stranded (ds) RNA, the precursor of siRNAs and is critical for effective and amplified responses to virus infection. It is also important for the production of endogenous secondary siRNAs, such as phased siRNAs (phasiRNAs), which regulate several genes involved in development and adaptation. Transitivity on endogenous transcripts is very specific, utilizing special primary sRNAs, such as miRNAs with unique features, and particular ARGONAUTEs. In contrast, transitivity on transgene and virus (exogenous) transcripts is more generic. This dichotomy of responses implies the existence of a mechanism that differentiates self from non-self targets. In this work, we examine the possible mechanistic process behind the dichotomy and the intriguing counter-intuitive directionality of transitive sequence-spread in plants.
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38
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Marchais A, Chevalier C, Voinnet O. Extensive profiling in Arabidopsis reveals abundant polysome-associated 24-nt small RNAs including AGO5-dependent pseudogene-derived siRNAs. RNA (NEW YORK, N.Y.) 2019; 25:1098-1117. [PMID: 31138671 PMCID: PMC6800511 DOI: 10.1261/rna.069294.118] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2018] [Accepted: 04/07/2019] [Indexed: 05/19/2023]
Abstract
In a reductionist perspective, plant silencing small (s)RNAs are often classified as mediating nuclear transcriptional gene silencing (TGS) or cytosolic posttranscriptional gene silencing (PTGS). Among the PTGS diagnostics is the association of AGOs and their sRNA cargos with the translation apparatus. In Arabidopsis, this is observed for AGO1 loaded with micro(mi)RNAs and, accordingly, translational-repression (TR) is one layer of plant miRNA action. Using AGO1:miRNA-mediated TR as a paradigm, we explored, with two unrelated polysome-isolation methods, which, among the ten Arabidopsis AGOs and numerous sRNA classes, interact with translation. We found that representatives of all three AGO-clades associate with polysomes, including the TGS-effector AGO4 and stereotypical 24-nt sRNAs that normally mediate TGS of transposons/repeats. Strikingly, approximately half of these annotated 24-nt siRNAs displayed unique matches in coding regions/introns of genes, and in pseudogenes, but not in transposons/repeats commonly found in their vicinity. Protein-coding gene-derived 24-nt sRNAs correlate with gene-body methylation. Those derived from pseudogenes belong to two main clusters defined by their parental-gene expression patterns, and are vastly enriched in AGO5, itself found on polysomes. Based on their tight expression pattern in developing and mature siliques, their biogenesis, and genomic/epigenomic features of their loci-of-origin, we discuss potential roles for these hitherto unknown polysome-enriched, pseudogene-derived siRNAs.
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Affiliation(s)
- Antonin Marchais
- Department of Biology, Swiss Federal Institute of Technology (ETH), 8092 Zürich, Switzerland
| | - Clément Chevalier
- Department of Biology, Swiss Federal Institute of Technology (ETH), 8092 Zürich, Switzerland
| | - Olivier Voinnet
- Department of Biology, Swiss Federal Institute of Technology (ETH), 8092 Zürich, Switzerland
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39
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Prakash V, Chakraborty S. Identification of transcription factor binding sites on promoter of RNA dependent RNA polymerases ( RDRs) and interacting partners of RDR proteins through in silico analysis. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2019; 25:1055-1071. [PMID: 31402824 PMCID: PMC6656839 DOI: 10.1007/s12298-019-00660-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 12/20/2018] [Accepted: 03/25/2019] [Indexed: 05/14/2023]
Abstract
RNA silencing phenomenon in plants provides resistance to various pathogens and also, it maintains genome integrity. The process of RNA silencing is regulated by diverse proteins, among which RNA dependent RNA polymerases (RDRs) are very crucial for the amplification of small RNAs (sRNAs). Out of various RDR proteins present in plants, role of RDR1, RDR2 and RDR6 for providing resistance against various biotic stresses have been well documented. In contrast, very few information is available regarding the role of RDR3, RDR4 and RDR5 proteins in plant biology and stress response. Furthermore, the regulation of RDRs is not yet known. Here, we have carried out in silico studies for identification of the transcription factor (TF) binding sites on the promoter of RDR1-6 genes of various plant species. Among the TFs predicted to bind on the promoter of RDRs, MYB44, AS1/AS2, WRKY1 are the major one. Furthermore, putative interacting protein partners of RDRs proteins of tomato and rice were also predicted by STRING database which suggests that DCL (Dicer-like) proteins are strong candidate proteins as the interacting partners of RDRs. The knowledge of regulation of RDRs and its interacting protein partners might help in developing resistant plants to biotic stresses.
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Affiliation(s)
- Ved Prakash
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067 India
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40
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Zheng X, Fahlgren N, Abbasi A, Berry JC, Carrington JC. Antiviral ARGONAUTEs Against Turnip Crinkle Virus Revealed by Image-Based Trait Analysis. PLANT PHYSIOLOGY 2019; 180:1418-1435. [PMID: 31043494 PMCID: PMC6752898 DOI: 10.1104/pp.19.00121] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Accepted: 04/21/2019] [Indexed: 05/18/2023]
Abstract
RNA-based silencing functions as an important antiviral immunity mechanism in plants. Plant viruses evolved to encode viral suppressors of RNA silencing (VSRs) that interfere with the function of key components in the silencing pathway. As effectors in the RNA silencing pathway, ARGONAUTE (AGO) proteins are targeted by some VSRs, such as that encoded by Turnip crinkle virus (TCV). A VSR-deficient TCV mutant was used to identify AGO proteins with antiviral activities during infection. A quantitative phenotyping protocol using an image-based color trait analysis pipeline on the PlantCV platform, with temporal red, green, and blue imaging and a computational segmentation algorithm, was used to measure plant disease after TCV inoculation. This process captured and analyzed growth and leaf color of Arabidopsis (Arabidopsis thaliana) plants in response to virus infection over time. By combining this quantitative phenotypic data with molecular assays to detect local and systemic virus accumulation, AGO2, AGO3, and AGO7 were shown to play antiviral roles during TCV infection. In leaves, AGO2 and AGO7 functioned as prominent nonadditive, anti-TCV effectors, whereas AGO3 played a minor role. Other AGOs were required to protect inflorescence tissues against TCV. Overall, these results indicate that distinct AGO proteins have specialized, modular roles in antiviral defense across different tissues, and demonstrate the effectiveness of image-based phenotyping to quantify disease progression.
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Affiliation(s)
- Xingguo Zheng
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Noah Fahlgren
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Arash Abbasi
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
| | - Jeffrey C Berry
- Donald Danforth Plant Science Center, St. Louis, Missouri 63132
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41
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Nintemann SJ, Palmgren M, López-Marqués RL. Catch You on the Flip Side: A Critical Review of Flippase Mutant Phenotypes. TRENDS IN PLANT SCIENCE 2019; 24:468-478. [PMID: 30885637 DOI: 10.1016/j.tplants.2019.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 01/24/2019] [Accepted: 02/04/2019] [Indexed: 05/05/2023]
Abstract
Lipid flippases are integral membrane proteins that use ATP hydrolysis to power the generation of phospholipid asymmetry between the two leaflets of biological membranes, a process essential for cell survival. Although the first report of a plant lipid flippase was published in 2000, progress in the field has been slow, partially due to the high level of redundancy in this gene family. However, recently an increasing number of reports have examined the physiological function of lipid flippases, mainly in Arabidopsis thaliana. In this review we aim to summarize recent findings on the physiological relevance of lipid flippases in plant adaptation to a changing environment and caution against misinterpretation of pleiotropic effects in genetic studies of flippases.
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Affiliation(s)
- Sebastian J Nintemann
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Michael Palmgren
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
| | - Rosa Laura López-Marqués
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark; https://plen.ku.dk/english/research/transport_biology/blf/.
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42
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de Felippes FF. Gene Regulation Mediated by microRNA-Triggered Secondary Small RNAs in Plants. PLANTS 2019; 8:plants8050112. [PMID: 31035467 PMCID: PMC6572396 DOI: 10.3390/plants8050112] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 04/22/2019] [Accepted: 04/24/2019] [Indexed: 01/18/2023]
Abstract
In plants, proper development and response to abiotic and biotic stimuli requires an orchestrated regulation of gene expression. Small RNAs (sRNAs) are key molecules involved in this process, leading to downregulation of their target genes. Two main classes of sRNAs exist, the small interfering RNAs (siRNAs) and microRNAs (miRNAs). The role of the latter class in plant development and physiology is well known, with many examples of how miRNAs directly impact the expression of genes in cells where they are produced, with dramatic consequences to the life of the plant. However, there is an aspect of miRNA biology that is still poorly understood. In some cases, miRNA targeting can lead to the production of secondary siRNAs from its target. These siRNAs, which display a characteristic phased production pattern, can act in cis, reinforcing the initial silencing signal set by the triggering miRNA, or in trans, affecting genes that are unrelated to the initial target. In this review, the mechanisms and implications of this process in the gene regulation mediated by miRNAs will be discussed. This work will also explore techniques for gene silencing in plants that are based on this unique pathway.
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43
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Azevedo J, Picart C, Dureau L, Pontier D, Jaquinod-Kieffer S, Hakimi MA, Lagrange T. UAP56 associates with DRM2 and is localized to chromatin in Arabidopsis. FEBS Open Bio 2019; 9:973-985. [PMID: 30951268 PMCID: PMC6487834 DOI: 10.1002/2211-5463.12627] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Revised: 02/21/2019] [Accepted: 03/18/2019] [Indexed: 11/17/2022] Open
Abstract
Repeated sequence expression and transposable element mobilization are tightly controlled by multilayer processes, which include DNA 5′‐cytosine methylation. The RNA‐directed DNA methylation (RdDM) pathway, which uses siRNAs to guide sequence‐specific directed DNA methylation, emerged specifically in plants. RdDM ensures DNA methylation maintenance on asymmetric CHH sites and specifically initiates de novo methylation in all cytosine sequence contexts through the action of DRM DNA methyltransferases, of which DRM2 is the most prominent. The RdDM pathway has been well described, but how DRM2 is recruited onto DNA targets and associates with other RdDM factors remains unknown. To address these questions, we developed biochemical approaches to allow the identification of factors that may escape genetic screens, such as proteins encoded by multigenic families. Through both conventional and affinity purification of DRM2, we identified DEAD box RNA helicases U2AF56 Associated Protein 56 (UAP56a/b), which are widespread among eukaryotes, as new DRM2 partners. We have shown that, similar to DRM2 and other RdDM actors, UAP56 has chromatin‐associated protein properties. We confirmed this association both in vitro and in vivo in reproductive tissues. In addition, our experiments also suggest that UAP56 may exhibit differential distribution in cells depending on plant organ. While originally identified for its role in splicing, our study suggests that UAP56 may also have other roles, and our findings allow us to initiate discussion about its potential role in the RdDM pathway.
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Affiliation(s)
- Jacinthe Azevedo
- LGDP-UMR5096, CNRS, Perpignan, France.,LGDP-UMR5096, Université de Perpignan Via Domitia, France
| | - Claire Picart
- LGDP-UMR5096, CNRS, Perpignan, France.,LGDP-UMR5096, Université de Perpignan Via Domitia, France
| | - Laurent Dureau
- LGDP-UMR5096, CNRS, Perpignan, France.,LGDP-UMR5096, Université de Perpignan Via Domitia, France
| | - Dominique Pontier
- LGDP-UMR5096, CNRS, Perpignan, France.,LGDP-UMR5096, Université de Perpignan Via Domitia, France
| | - Sylvie Jaquinod-Kieffer
- Laboratoire Biologie Grande Echelle, Institut de Biosciences et Biotechnologies de Grenoble, UMR_S 1038, CEA, INSERM, Université Grenoble Alpes, France
| | - Mohamed-Ali Hakimi
- Institute for Advanced Biosciences (IAB), Team Host-pathogen Interactions and Immunity to Infection, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, France
| | - Thierry Lagrange
- LGDP-UMR5096, CNRS, Perpignan, France.,LGDP-UMR5096, Université de Perpignan Via Domitia, France
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44
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Reagan BC, Ganusova EE, Fernandez JC, McCray TN, Burch-Smith TM. RNA on the move: The plasmodesmata perspective. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 275:1-10. [PMID: 30107876 DOI: 10.1016/j.plantsci.2018.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2018] [Revised: 05/25/2018] [Accepted: 07/04/2018] [Indexed: 05/11/2023]
Abstract
It is now widely accepted that plant RNAs can have effects at sites far away from their sites of synthesis. Cellular mRNA transcripts, endogenous small RNAs and defense-related small RNAs all move from cell to cell via plasmodesmata (PD), and may even move long distances in the phloem. Despite their small size, PD have complicated substructures, and the area of the pore available for RNA trafficking can be remarkably small. The intent of this review is to bring into focus the role of PD in cell-to-cell and long distance communication in plants. We consider how cellular RNAs could move through the cell to the PD and thence through PD. The protein composition of PD and the possible roles of PD proteins in RNA trafficking are also discussed. Recent evidence for RNA metabolism in organelles acting as a factor in controlling PD flux is also presented, highlighting new aspects of plant intra- and intercellular communication. It is clear that while the phenomenon of RNA mobility is common and essential, many questions remain, and these have been highlighted throughout this review.
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Affiliation(s)
- Brandon C Reagan
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Elena E Ganusova
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Jessica C Fernandez
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tyra N McCray
- School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, United States
| | - Tessa M Burch-Smith
- Department of Biochemistry & Cellular and Molecular Biology, University of Tennessee, Knoxville, TN 37996, United States; School of Genome Science and Technology, University of Tennessee, Knoxville, TN 37996, United States.
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45
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Montavon T, Kwon Y, Zimmermann A, Hammann P, Vincent T, Cognat V, Bergdoll M, Michel F, Dunoyer P. Characterization of DCL4 missense alleles provides insights into its ability to process distinct classes of dsRNA substrates. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 95:204-218. [PMID: 29682831 DOI: 10.1111/tpj.13941] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Revised: 03/10/2018] [Accepted: 04/05/2018] [Indexed: 05/10/2023]
Abstract
In the model plant Arabidopsis thaliana, four Dicer-like proteins (DCL1-4) mediate the production of various classes of small RNAs (sRNAs). Among these four proteins, DCL4 is by far the most versatile RNaseIII-like enzyme, and previously identified dcl4 missense alleles were shown to uncouple the production of the various classes of DCL4-dependent sRNAs. Yet little is known about the molecular mechanism behind this uncoupling. Here, by studying the subcellular localization, interactome and binding to the sRNA precursors of three distinct dcl4 missense alleles, we simultaneously highlight the absolute requirement of a specific residue in the helicase domain for the efficient production of all DCL4-dependent sRNAs, and identify, within the PAZ domain, an important determinant of DCL4 versatility that is mandatory for the efficient processing of intramolecular fold-back double-stranded RNA (dsRNA) precursors, but that is dispensable for the production of small interfering RNAs (siRNAs) from RDR-dependent dsRNA susbtrates. This study not only provides insights into the DCL4 mode of action, but also delineates interesting tools to further study the complexity of RNA silencing pathways in plants, and possibly other organisms.
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Affiliation(s)
- Thomas Montavon
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Yerim Kwon
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Aude Zimmermann
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Philippe Hammann
- Institut de Biologie Moléculaire et Cellulaire du CNRS, FRC1589, Plateforme Protéomique Strasbourg - Esplanade, Université de Strasbourg, F-67000, Strasbourg, France
| | - Timothée Vincent
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Valérie Cognat
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Marc Bergdoll
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Fabrice Michel
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
| | - Patrice Dunoyer
- Institut de Biologie Moléculaire des Plantes du CNRS, UPR2357, Université de Strasbourg, F-67000, Strasbourg, France
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46
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Kørner CJ, Pitzalis N, Peña EJ, Erhardt M, Vazquez F, Heinlein M. Crosstalk between PTGS and TGS pathways in natural antiviral immunity and disease recovery. NATURE PLANTS 2018; 4:157-164. [PMID: 29497161 DOI: 10.1038/s41477-018-0117-x] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Accepted: 01/31/2018] [Indexed: 05/22/2023]
Abstract
Virus-induced diseases cause severe damage to cultivated plants, resulting in crop losses. Certain plant-virus interactions allow disease recovery at later stages of infection and have the potential to reveal important molecular targets for achieving disease control. Although recovery is known to involve antiviral RNA silencing1,2, the specific components of the many plant RNA silencing pathways 3 required for recovery are not known. We found that Arabidopsis thaliana plants infected with oilseed rape mosaic virus (ORMV) undergo symptom recovery. The recovered leaves contain infectious, replicating virus, but exhibit a loss of viral suppressor of RNA silencing (VSR) protein activity. We demonstrate that recovery depends on the 21-22 nt siRNA-mediated post-transcriptional gene silencing (PTGS) pathway and on components of a transcriptional gene silencing (TGS) pathway that is known to facilitate non-cell-autonomous silencing signalling. Collectively, our observations indicate that recovery reflects the establishment of a tolerant state in infected tissues and occurs following robust delivery of antiviral secondary siRNAs from source to sink tissues, and establishment of a dosage able to block the VSR activity involved in the formation of disease symptoms.
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Affiliation(s)
- Camilla Julie Kørner
- Zurich-Basel Plant Science Center, Department of Environmental Sciences, University of Basel, Basel, Switzerland
| | - Nicolas Pitzalis
- Université de Strasbourg, CNRS, IBMP UPR 2357, Strasbourg, France
| | - Eduardo José Peña
- Université de Strasbourg, CNRS, IBMP UPR 2357, Strasbourg, France
- Instituto de Biotecnología y Biología Molecular, Facultad de Ciencias Exactas, UNLP-CONICET, La Plata, Buenos Aires, Argentina
| | - Mathieu Erhardt
- Université de Strasbourg, CNRS, IBMP UPR 2357, Strasbourg, France
| | - Franck Vazquez
- Zurich-Basel Plant Science Center, Department of Environmental Sciences, University of Basel, Basel, Switzerland
- MDPI, Basel, Switzerland
| | - Manfred Heinlein
- Zurich-Basel Plant Science Center, Department of Environmental Sciences, University of Basel, Basel, Switzerland.
- Université de Strasbourg, CNRS, IBMP UPR 2357, Strasbourg, France.
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47
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von Born P, Bernardo-Faura M, Rubio-Somoza I. An artificial miRNA system reveals that relative contribution of translational inhibition to miRNA-mediated regulation depends on environmental and developmental factors in Arabidopsis thaliana. PLoS One 2018; 13:e0192984. [PMID: 29451902 PMCID: PMC5815599 DOI: 10.1371/journal.pone.0192984] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 02/01/2018] [Indexed: 11/24/2022] Open
Abstract
Development and fitness of any organism rely on properly controlled gene expression. This is especially true for plants, as their development is determined by both internal and external cues. MicroRNAs (miRNAs) are embedded in the genetic cascades that integrate and translate those cues into developmental programs. miRNAs negatively regulate their target genes mainly post-transcriptionally through two co-existing mechanisms; mRNA cleavage and translational inhibition. Despite our increasing knowledge about the genetic and biochemical processes involved in those concurrent mechanisms, little is known about their relative contributions to the overall miRNA-mediated regulation. Here we show that co-existence of cleavage and translational inhibition is dependent on growth temperature and developmental stage. We found that efficiency of an artificial miRNA-mediated (amiRNA) gene silencing declines with age during vegetative development in a temperature-dependent manner. That decline is mainly due to a reduction on the contribution from translational inhibition. Both, temperature and developmental stage were also found to affect mature amiRNA accumulation and the expression patterns of the core players involved in miRNA biogenesis and action. Therefore, that suggests that each miRNA family specifically regulates their respective targets, while temperature and growth might influence the performance of miRNA-dependent regulation in a more general way.
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Affiliation(s)
- Patrick von Born
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | | | - Ignacio Rubio-Somoza
- Department of Molecular Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
- Molecular Reprogramming and Evolution Laboratory. Centre for Research in Agricultural Genomics, Barcelona, Spain
- * E-mail:
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48
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Bologna NG, Iselin R, Abriata LA, Sarazin A, Pumplin N, Jay F, Grentzinger T, Dal Peraro M, Voinnet O. Nucleo-cytosolic Shuttling of ARGONAUTE1 Prompts a Revised Model of the Plant MicroRNA Pathway. Mol Cell 2018; 69:709-719.e5. [PMID: 29398448 DOI: 10.1016/j.molcel.2018.01.007] [Citation(s) in RCA: 141] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 11/09/2017] [Accepted: 01/04/2018] [Indexed: 10/18/2022]
Abstract
Unlike in metazoans, plant microRNAs (miRNAs) undergo stepwise nuclear maturation before engaging cytosolic, sequence-complementary transcripts in association with the silencing effector protein ARGONAUTE1 (AGO1). Since their discovery, how and under which form plant miRNAs translocate to the cytosol has remained unclear, as has their sub-cellular AGO1 loading site(s). Here, we show that the N termini of all plant AGO1s contain a nuclear-localization (NLS) and nuclear-export signal (NES) that, in Arabidopsis thaliana (At), enables AtAGO1 nucleo-cytosolic shuttling in a Leptomycin-B-inhibited manner, diagnostic of CRM1(EXPO1)/NES-dependent nuclear export. Nuclear-only AtAGO1 contains the same 2'O-methylated miRNA cohorts as its nucleo-cytosolic counterpart, but it preferentially interacts with the miRNA loading chaperone HSP90. Furthermore, mature miRNA translocation and miRNA-mediated silencing both require AtAGO1 nucleo-cytosolic shuttling. These findings lead us to propose a substantially revised view of the plant miRNA pathway in which miRNAs are matured, methylated, loaded into AGO1 in the nucleus, and exported to the cytosol as AGO1:miRNA complexes in a CRM1(EXPO1)/NES-dependent manner.
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Affiliation(s)
- Nicolas G Bologna
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Raphael Iselin
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Luciano A Abriata
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland; Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland
| | - Alexis Sarazin
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Nathan Pumplin
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland; Department of Plant Sciences, University of California, Davis, California 95616, USA
| | - Florence Jay
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Thomas Grentzinger
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland; Swiss Institute of Bioinformatics, Lausanne 1015, Switzerland
| | - Olivier Voinnet
- Department of Biology, Swiss Federal Institute of Technology (ETH), Universitätstrasse 2, Zürich 8092, Switzerland.
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49
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Chantarachot T, Bailey-Serres J. Polysomes, Stress Granules, and Processing Bodies: A Dynamic Triumvirate Controlling Cytoplasmic mRNA Fate and Function. PLANT PHYSIOLOGY 2018; 176:254-269. [PMID: 29158329 PMCID: PMC5761823 DOI: 10.1104/pp.17.01468] [Citation(s) in RCA: 109] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2017] [Accepted: 11/17/2017] [Indexed: 05/05/2023]
Abstract
Discoveries illuminate highly regulated dynamics of mRNA translation, sequestration, and degradation within the cytoplasm of plants.
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Affiliation(s)
- Thanin Chantarachot
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, California 92521
| | - Julia Bailey-Serres
- Center for Plant Cell Biology, Department of Botany and Plant Sciences, University of California, Riverside, California 92521
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50
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Yu Y, Jia T, Chen X. The 'how' and 'where' of plant microRNAs. THE NEW PHYTOLOGIST 2017; 216:1002-1017. [PMID: 29048752 PMCID: PMC6040672 DOI: 10.1111/nph.14834] [Citation(s) in RCA: 253] [Impact Index Per Article: 36.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2017] [Accepted: 08/21/2017] [Indexed: 05/18/2023]
Abstract
Contents 1002 I. 1002 II. 1007 III. 1010 IV. 1013 1013 References 1013 SUMMARY: MicroRNAs (miRNAs) are small non-coding RNAs, of typically 20-24 nt, that regulate gene expression post-transcriptionally through sequence complementarity. Since the identification of the first miRNA, lin-4, in the nematode Caenorhabditis elegans in 1993, thousands of miRNAs have been discovered in animals and plants, and their regulatory roles in numerous biological processes have been uncovered. In plants, research efforts have established the major molecular framework of miRNA biogenesis and modes of action, and are beginning to elucidate the mechanisms of miRNA degradation. Studies have implicated restricted and surprising subcellular locations in which miRNA biogenesis or activity takes place. In this article, we summarize the current knowledge on how plant miRNAs are made and degraded, and how they repress target gene expression. We discuss not only the players involved in these processes, but also the subcellular sites in which these processes are known or implicated to take place. We hope to raise awareness that the cell biology of miRNAs holds the key to a full understanding of these enigmatic molecules.
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Affiliation(s)
- Yu Yu
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Tianran Jia
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA
| | - Xuemei Chen
- Department of Botany and Plant Sciences, Institute of Integrative Genome Biology, University of California, Riverside, CA 92521, USA
- Department of Botany and Plant Sciences, Howard Hughes Medical Institute, University of California, Riverside, CA 92521, USA
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