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Wang J, Hsu Y, Lee Y, Lin N. Importin α2 participates in RNA interference against bamboo mosaic virus accumulation in Nicotiana benthamiana via NbAGO10a-mediated small RNA clearance. MOLECULAR PLANT PATHOLOGY 2024; 25:e13422. [PMID: 38279848 PMCID: PMC10799208 DOI: 10.1111/mpp.13422] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Revised: 12/20/2023] [Accepted: 12/21/2023] [Indexed: 01/29/2024]
Abstract
Karyopherins, the nucleocytoplasmic transporters, participate in multiple RNA silencing stages by transporting associated proteins into the nucleus. Importin α is a member of karyopherins and has been reported to facilitate virus infection via nuclear import of viral proteins. Unlike other RNA viruses, silencing of importin α2 (α2i) by virus-induced gene silencing (VIGS) boosted the titre of bamboo mosaic virus (BaMV) in protoplasts, and inoculated and systemic leaves of Nicotiana benthamiana. The enhanced BaMV accumulation in importin α2i plants was linked to reduced levels of RDR6-dependent secondary virus-derived small-interfering RNAs (vsiRNAs). Small RNA-seq revealed importin α2 silencing did not affect the abundance of siRNAs derived from host mRNAs but significantly reduced the 21 and 22 nucleotide vsiRNAs in BaMV-infected plants. Deletion of BaMV TGBp1, an RNA silencing suppressor, compromised importin α2i-mediated BaMV enhancement. Moreover, silencing of importin α2 upregulated NbAGO10a, a proviral protein recruited by TGBp1 for BaMV vsiRNAs clearance, but hindered the nuclear import of NbAGO10a. Taken together, these results indicate that importin α2 acts as a negative regulator of BaMV invasion by controlling the expression and nucleocytoplasmic shuttling of NbAGO10a, which removes vsiRNAs via the TGBp1-NbAGO10a-SDN1 pathway. Our findings reveal the hidden antiviral mechanism of importin α2 in countering BaMV infection in N. benthamiana.
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Affiliation(s)
- Jiun‐Da Wang
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan
| | - Yau‐Heiu Hsu
- Graduate Institute of BiotechnologyNational Chung Hsing UniversityTaichungTaiwan
| | - Yun‐Shien Lee
- Department of BiotechnologyMing Chuan UniversityTaipeiTaiwan
| | - Na‐Sheng Lin
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan
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Alazem M, He MH, Chang CH, Cheng N, Lin NS. Disrupting the Homeostasis of High Mobility Group Protein Promotes the Systemic Movement of Bamboo mosaic virus. FRONTIERS IN PLANT SCIENCE 2020; 11:597665. [PMID: 33424893 PMCID: PMC7793662 DOI: 10.3389/fpls.2020.597665] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 11/11/2020] [Indexed: 05/21/2023]
Abstract
Viruses hijack various organelles and machineries for their replication and movement. Ever more lines of evidence indicate that specific nuclear factors are involved in systemic trafficking of several viruses. However, how such factors regulate viral systemic movement remains unclear. Here, we identify a novel role for Nicotiana benthamiana high mobility group nucleoprotein (NbHMG1/2a) in virus movement. Although infection of N. benthamiana with Bamboo mosaic virus (BaMV) decreased NbHMG1/2a expression levels, nuclear-localized NbHMG1/2a protein was shuttled out of the nucleus into cytoplasm upon BaMV infection. NbHMG1/2a knockdown or even overexpression did not affect BaMV accumulation in inoculated leaves, but it did enhance systemic movement of the virus. Interestingly, the positive regulator Rap-GTPase activation protein 1 was highly upregulated upon infection with BaMV, whereas the negative regulator thioredoxin h protein was greatly reduced, no matter if NbHMG1a/2a was silenced or overexpressed. Our findings indicate that NbHMG1/2a may have a role in plant defense responses. Once its homeostasis is disrupted, expression of relevant host factors may be perturbed that, in turn, facilitates BaMV systemic movement.
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Richert-Pöggeler KR, Franzke K, Hipp K, Kleespies RG. Electron Microscopy Methods for Virus Diagnosis and High Resolution Analysis of Viruses. Front Microbiol 2019; 9:3255. [PMID: 30666247 PMCID: PMC6330349 DOI: 10.3389/fmicb.2018.03255] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Accepted: 12/14/2018] [Indexed: 01/29/2023] Open
Abstract
The term "virosphere" describes both the space where viruses are found and the space they influence, and can extend to their impact on the environment, highlighting the complexity of the interactions involved. Studying the biology of viruses and the etiology of virus disease is crucial to the prevention of viral disease, efficient and reliable virus diagnosis, and virus control. Electron microscopy (EM) is an essential tool in the detection and analysis of virus replication. New EM methods and ongoing technical improvements offer a broad spectrum of applications, allowing in-depth investigation of viral impact on not only the host but also the environment. Indeed, using the most up-to-date electron cryomicroscopy methods, such investigations are now close to atomic resolution. In combination with bioinformatics, the transition from 2D imaging to 3D remodeling allows structural and functional analyses that extend and augment our knowledge of the astonishing diversity in virus structure and lifestyle. In combination with confocal laser scanning microscopy, EM enables live imaging of cells and tissues with high-resolution analysis. Here, we describe the pivotal role played by EM in the study of viruses, from structural analysis to the biological relevance of the viral metagenome (virome).
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Affiliation(s)
- Katja R. Richert-Pöggeler
- Federal Research Center for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn Institute, Braunschweig, Germany
| | - Kati Franzke
- Institute of Infectiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Katharina Hipp
- Electron Microscopy Facility, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Regina G. Kleespies
- Federal Research Centre for Cultivated Plants, Institute for Biological Control, Julius Kühn Institute, Darmstadt, Germany
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Richert-Pöggeler KR, Franzke K, Hipp K, Kleespies RG. Electron Microscopy Methods for Virus Diagnosis and High Resolution Analysis of Viruses. Front Microbiol 2018. [PMID: 30666247 DOI: 10.3389/fmicb.2018.03255.ecollection] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/22/2023] Open
Abstract
The term "virosphere" describes both the space where viruses are found and the space they influence, and can extend to their impact on the environment, highlighting the complexity of the interactions involved. Studying the biology of viruses and the etiology of virus disease is crucial to the prevention of viral disease, efficient and reliable virus diagnosis, and virus control. Electron microscopy (EM) is an essential tool in the detection and analysis of virus replication. New EM methods and ongoing technical improvements offer a broad spectrum of applications, allowing in-depth investigation of viral impact on not only the host but also the environment. Indeed, using the most up-to-date electron cryomicroscopy methods, such investigations are now close to atomic resolution. In combination with bioinformatics, the transition from 2D imaging to 3D remodeling allows structural and functional analyses that extend and augment our knowledge of the astonishing diversity in virus structure and lifestyle. In combination with confocal laser scanning microscopy, EM enables live imaging of cells and tissues with high-resolution analysis. Here, we describe the pivotal role played by EM in the study of viruses, from structural analysis to the biological relevance of the viral metagenome (virome).
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Affiliation(s)
- Katja R Richert-Pöggeler
- Federal Research Center for Cultivated Plants, Institute for Epidemiology and Pathogen Diagnostics, Julius Kühn Institute, Braunschweig, Germany
| | - Kati Franzke
- Institute of Infectiology, Friedrich-Loeffler-Institut, Federal Research Institute for Animal Health, Greifswald-Insel Riems, Germany
| | - Katharina Hipp
- Electron Microscopy Facility, Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Regina G Kleespies
- Federal Research Centre for Cultivated Plants, Institute for Biological Control, Julius Kühn Institute, Darmstadt, Germany
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Chang CH, Hsu FC, Lee SC, Lo YS, Wang JD, Shaw J, Taliansky M, Chang BY, Hsu YH, Lin NS. The Nucleolar Fibrillarin Protein Is Required for Helper Virus-Independent Long-Distance Trafficking of a Subviral Satellite RNA in Plants. THE PLANT CELL 2016; 28:2586-2602. [PMID: 27702772 PMCID: PMC5134973 DOI: 10.1105/tpc.16.00071] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 08/30/2016] [Accepted: 09/30/2016] [Indexed: 05/03/2023]
Abstract
RNA trafficking plays pivotal roles in regulating plant development, gene silencing, and adaptation to environmental stress. Satellite RNAs (satRNAs), parasites of viruses, depend on their helper viruses (HVs) for replication, encapsidation, and efficient spread. However, it remains largely unknown how satRNAs interact with viruses and the cellular machinery to undergo trafficking. Here, we show that the P20 protein of Bamboo mosaic potexvirus satRNA (satBaMV) can functionally complement in trans the systemic trafficking of P20-defective satBaMV in infected Nicotiana benthamiana The transgene-derived satBaMV, uncoupled from HV replication, was able to move autonomously across a graft union identified by RT-qPCR, RNA gel blot, and in situ RT-PCR analyses. Coimmunoprecipitation experiments revealed that the major nucleolar protein fibrillarin is coprecipitated in the P20 protein complex. Notably, silencing fibrillarin suppressed satBaMV-, but not HV-, phloem-based movement following grafting or coinoculation with HV Confocal microscopy revealed that the P20 protein colocalized with fibrillarin in the nucleoli and formed punctate structures associated with plasmodesmata. The mobile satBaMV RNA appears to exist as ribonucleoprotein (RNP) complex composed of P20 and fibrillarin, whereas BaMV movement proteins, capsid protein, and BaMV RNA are recruited with HV coinfection. Taken together, our findings provide insight into movement of satBaMV via the fibrillarin-satBaMV-P20 RNP complex in phloem-mediated systemic trafficking.
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Affiliation(s)
- Chih-Hao Chang
- Institute of Plant Biology, National Taiwan University, Taipei 11106, Taiwan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Fu-Chen Hsu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Shu-Chuan Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yih-Shan Lo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Jiun-Da Wang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Jane Shaw
- The James Hutton Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Michael Taliansky
- The James Hutton Institute, Invergowrie, Dundee DD2 5DA, United Kingdom
| | - Ban-Yang Chang
- Department of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Na-Sheng Lin
- Institute of Plant Biology, National Taiwan University, Taipei 11106, Taiwan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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Krupovic M, Kuhn JH, Fischer MG. A classification system for virophages and satellite viruses. Arch Virol 2015; 161:233-47. [PMID: 26446887 DOI: 10.1007/s00705-015-2622-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Accepted: 09/21/2015] [Indexed: 11/28/2022]
Abstract
Satellite viruses encode structural proteins required for the formation of infectious particles but depend on helper viruses for completing their replication cycles. Because of this unique property, satellite viruses that infect plants, arthropods, or mammals, as well as the more recently discovered satellite-like viruses that infect protists (virophages), have been grouped with other, so-called "sub-viral agents." For the most part, satellite viruses are therefore not classified. We argue that possession of a coat-protein-encoding gene and the ability to form virions are the defining features of a bona fide virus. Accordingly, all satellite viruses and virophages should be consistently classified within appropriate taxa. We propose to create four new genera - Albetovirus, Aumaivirus, Papanivirus, and Virtovirus - for positive-sense single-stranded (+) RNA satellite viruses that infect plants and the family Sarthroviridae, including the genus Macronovirus, for (+)RNA satellite viruses that infect arthopods. For double-stranded DNA virophages, we propose to establish the family Lavidaviridae, including two genera, Sputnikvirus and Mavirus.
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Affiliation(s)
- Mart Krupovic
- Unité Biologie Moléculaire du Gène chez les Extrêmophiles, Department of Microbiology, Institut Pasteur, Paris, France.
| | - Jens H Kuhn
- Integrated Research Facility at Fort Detrick, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Fort Detrick, Frederick, MD, USA
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Gene from a novel plant virus satellite from grapevine identifies a viral satellite lineage. Virus Genes 2013; 47:114-8. [DOI: 10.1007/s11262-013-0921-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Accepted: 05/11/2013] [Indexed: 11/30/2022]
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Vijayapalani P, Chen JCF, Liou MR, Chen HC, Hsu YH, Lin NS. Phosphorylation of bamboo mosaic virus satellite RNA (satBaMV)-encoded protein P20 downregulates the formation of satBaMV-P20 ribonucleoprotein complex. Nucleic Acids Res 2012; 40:638-49. [PMID: 21965537 PMCID: PMC3258126 DOI: 10.1093/nar/gkr705] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 08/14/2011] [Accepted: 08/15/2011] [Indexed: 01/13/2023] Open
Abstract
Bamboo mosaic virus (BaMV) satellite RNA (satBaMV) depends on BaMV for its replication and encapsidation. SatBaMV-encoded P20 protein is an RNA-binding protein that facilitates satBaMV systemic movement in co-infected plants. Here, we examined phosphorylation of P20 and its regulatory functions. Recombinant P20 (rP20) was phosphorylated by host cellular kinase(s) in vitro, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and mutational analyses revealed Ser-11 as the phosphorylation site. The phosphor-mimic rP20 protein interactions with satBaMV-translated mutant P20 were affected. In overlay assay, the Asp mutation at S11 (S11D) completely abolished the self-interaction of rP20 and significantly inhibited the interaction with both the WT and S11A rP20. In chemical cross-linking assays, S11D failed to oligomerize. Electrophoretic mobility shift assay and subsequent Hill transformation analysis revealed a low affinity of the phospho-mimicking rP20 for satBaMV RNA. Substantial modulation of satBaMV RNA conformation upon interaction with nonphospho-mimic rP20 in circular dichroism analysis indicated formation of stable satBaMV ribonucleoprotein complexes. The dissimilar satBaMV translation regulation of the nonphospho- and phospho-mimic rP20 suggests that phosphorylation of P20 in the ribonucleoprotein complex converts the translation-incompetent satBaMV RNA to messenger RNA. The phospho-deficient or phospho-mimicking P20 mutant of satBaMV delayed the systemic spread of satBaMV in co-infected Nicotiana benthamiana with BaMV. Thus, satBaMV likely regulates the formation of satBaMV RNP complex during co-infection in planta.
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Affiliation(s)
- Paramasivan Vijayapalani
- The Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
| | - Jeff Chien-Fu Chen
- The Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
| | - Ming-Ru Liou
- The Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
| | - Hsin-Chuan Chen
- The Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
| | - Yau-Heiu Hsu
- The Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
| | - Na-Sheng Lin
- The Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
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Lin KY, Cheng CP, Chang BCH, Wang WC, Huang YW, Lee YS, Huang HD, Hsu YH, Lin NS. Global analyses of small interfering RNAs derived from Bamboo mosaic virus and its associated satellite RNAs in different plants. PLoS One 2010; 5:e11928. [PMID: 20689857 PMCID: PMC2914070 DOI: 10.1371/journal.pone.0011928] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Accepted: 07/08/2010] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Satellite RNAs (satRNAs), virus parasites, are exclusively associated with plant virus infection and have attracted much interest over the last 3 decades. Upon virus infection, virus-specific small interfering RNAs (vsiRNAs) are produced by dicer-like (DCL) endoribonucleases for anti-viral defense. The composition of vsiRNAs has been studied extensively; however, studies of satRNA-derived siRNAs (satsiRNAs) or siRNA profiles after satRNA co-infection are limited. Here, we report on the small RNA profiles associated with infection with Bamboo mosaic virus (BaMV) and its two satellite RNAs (satBaMVs) in Nicotiana benthamiana and Arabidopsis thaliana. METHODOLOGY/PRINCIPAL FINDINGS Leaves of N. benthamiana or A. thaliana inoculated with water, BaMV alone or co-inoculated with interfering or noninterfering satBaMV were collected for RNA extraction, then large-scale Solexa sequencing. Up to about 20% of total siRNAs as BaMV-specific siRNAs were accumulated in highly susceptible N. benthamiana leaves inoculated with BaMV alone or co-inoculated with noninterfering satBaMV; however, only about 0.1% of vsiRNAs were produced in plants co-infected with interfering satBaMV. The abundant region of siRNA distribution along BaMV and satBaMV genomes differed by host but not by co-infection with satBaMV. Most of the BaMV and satBaMV siRNAs were 21 or 22 nt, of both (+) and (-) polarities; however, a higher proportion of 22-nt BaMV and satBaMV siRNAs were generated in N. benthamiana than in A. thaliana. Furthermore, the proportion of non-viral 24-nt siRNAs was greatly increased in N. benthamiana after virus infection. CONCLUSIONS/SIGNIFICANCE The overall composition of vsiRNAs and satsiRNAs in the infected plants reflect the combined action of virus, satRNA and different DCLs in host plants. Our findings suggest that the structure and/or sequence demands of various DCLs in different hosts may result in differential susceptibility to the same virus. DCL2 producing 24-nt siRNAs under biotic stresses may play a vital role in the antiviral mechanism in N. benthamiana.
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Affiliation(s)
- Kuan-Yu Lin
- Institute of Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Chi-Ping Cheng
- Department of Life Science, Tzu Chi University, Hualien, Taiwan
| | | | - Wei-Chi Wang
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsin-Chu, Taiwan
| | - Ying-Wen Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Yun-Shien Lee
- Department of Biotechnology, Ming Chuan University, Taoyuan, Taiwan
| | - Hsien-Da Huang
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsin-Chu, Taiwan
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Na-Sheng Lin
- Institute of Biotechnology, National Cheng Kung University, Tainan, Taiwan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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Satellite RNAs and Satellite Viruses of Plants. Viruses 2009; 1:1325-50. [PMID: 21994595 PMCID: PMC3185516 DOI: 10.3390/v1031325] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 12/07/2009] [Accepted: 12/07/2009] [Indexed: 12/24/2022] Open
Abstract
The view that satellite RNAs (satRNAs) and satellite viruses are purely molecular parasites of their cognate helper viruses has changed. The molecular mechanisms underlying the synergistic and/or antagonistic interactions among satRNAs/satellite viruses, helper viruses, and host plants are beginning to be comprehended. This review aims to summarize the recent achievements in basic and practical research, with special emphasis on the involvement of RNA silencing mechanisms in the pathogenicity, population dynamics, and, possibly, the origin(s) of these subviral agents. With further research following current trends, the comprehensive understanding of satRNAs and satellite viruses could lead to new insights into the trilateral interactions among host plants, viruses, and satellites.
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