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Butkovic A, Dolja VV, Koonin EV, Krupovic M. Plant virus movement proteins originated from jelly-roll capsid proteins. PLoS Biol 2023; 21:e3002157. [PMID: 37319262 DOI: 10.1371/journal.pbio.3002157] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Accepted: 05/11/2023] [Indexed: 06/17/2023] Open
Abstract
Numerous, diverse plant viruses encode movement proteins (MPs) that aid the virus movement through plasmodesmata, the plant intercellular channels. MPs are essential for virus spread and propagation in distal tissues, and several unrelated MPs have been identified. The 30K superfamily of MPs (named after the molecular mass of tobacco mosaic virus (TMV) MP, the classical model of plant virology) is the largest and most diverse MP variety, represented in 16 virus families, but its evolutionary origin remained obscure. Here, we show that the core structural domain of the 30K MPs is homologous to the jelly-roll domain of the capsid proteins (CPs) of small RNA and DNA viruses, in particular, those infecting plants. The closest similarity was observed between the 30K MPs and the CPs of the viruses in the families Bromoviridae and Geminiviridae. We hypothesize that the MPs evolved via duplication or horizontal acquisition of the CP gene in a virus that infected an ancestor of vascular plants, followed by neofunctionalization of one of the paralogous CPs, potentially through the acquisition of unique N- and C-terminal regions. During the subsequent coevolution of viruses with diversifying vascular plants, the 30K MP genes underwent explosive horizontal spread among emergent RNA and DNA viruses, likely permitting viruses of insects and fungi that coinfected plants to expand their host ranges, molding the contemporary plant virome.
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Affiliation(s)
- Anamarija Butkovic
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Archaeal Virology Unit, Paris, France
| | - Valerian V Dolja
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, United States of America
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, Maryland, United States of America
| | - Mart Krupovic
- Institut Pasteur, Université Paris Cité, CNRS UMR6047, Archaeal Virology Unit, Paris, France
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He C, Xing F, Zhao X, Li S, Zhan B, Liu Z, Xu T, Gao D, Dong Z, Wang H, Zhang Z. The coat protein of the ilarvirus prunus necrotic ringspot virus mediates long-distance movement. J Gen Virol 2023; 104. [PMID: 36802334 DOI: 10.1099/jgv.0.001829] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2023] Open
Abstract
The coat protein (CP) of plant viruses generally has multiple functions involving infection, replication, movement and pathogenicity. Functions of the CP of prunus necrotic ringspot virus (PNRSV), the causal agent of several threatening diseases of Prunus fruit trees, are poorly studied. Previously, we identified a novel virus in apple, apple necrotic mosaic virus (ApNMV), which is phylogenetically related to PNRSV and probably associated with apple mosaic disease in China. Full-length cDNA clones of PNRSV and ApNMV were constructed, and both are infectious in cucumber (Cucumis sativus L.), an experimental host. PNRSV exhibited higher systemic infection efficiency with more severe symptoms than ApNMV. Reassortment analysis of genomic RNA segments 1-3 found that RNA3 of PNRSV could enhance the long-distance movement of an ApNMV chimaera in cucumber, indicating the association of RNA3 of PNRSV with viral long-distance movement. Deletion mutagenesis of the PNRSV CP showed that the basic motif from amino acids 38 to 47 was crucial for the CP to maintain the systemic movement of PNRSV. Moreover, we found that arginine residues 41, 43 and 47 codetermine viral long-distance movement. The findings demonstrate that the CP of PNRSV is required for long-distance movement in cucumber, which expands the functions of ilarvirus CPs in systemic infection. For the first time, we identified involvement of Ilarvirus CP protein during long-distance movement.
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Affiliation(s)
- Chengyong He
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing 100193, PR China
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Fei Xing
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Xiaoli Zhao
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing 100193, PR China
| | - Shifang Li
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Binhui Zhan
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Zhen Liu
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
| | - Tengfei Xu
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing 100193, PR China
| | - Dehang Gao
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing 100193, PR China
| | - Zhenfei Dong
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing 100193, PR China
| | - Hongqing Wang
- Department of Fruit Science, College of Horticulture, China Agricultural University, Beijing 100193, PR China
| | - Zhixiang Zhang
- State Key Laboratory of Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, PR China
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3
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Kang SH, Aknadibossian V, Kharel L, Mudiyanselage SDD, Wang Y, Folimonova SY. The Intriguing Conundrum of a Nonconserved Multifunctional Protein of Citrus Tristeza Virus That Interacts with a Viral Long Non-Coding RNA. Viruses 2021; 13:2129. [PMID: 34834936 PMCID: PMC8625556 DOI: 10.3390/v13112129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/12/2021] [Accepted: 10/19/2021] [Indexed: 01/26/2023] Open
Abstract
Citrus tristeza virus (CTV), the largest non-segmented plant RNA virus, has several peculiar features, among which is the production of a 5'-terminal long non-coding RNA (lncRNA) termed low-molecular-weight tristeza 1 (LMT1). In this study, we found that p33, a unique viral protein that performs multiple functions in the virus infection cycle, specifically binds LMT1, both in vivo and in vitro. These results were obtained through the expression of p33 under the context of the wild type virus infection or along with a mutant CTV variant that does not produce LMT1 as well as via ectopic co-expression of p33 with LMT1 in Nicotiana benthamiana leaves followed by RNA immunoprecipitation and rapid amplification of cDNA ends assays. Further experiments in which a recombinant p33 protein and an in vitro transcribed full-length LMT1 RNA or its truncated fragments were subjected to an electrophoretic mobility shift assay demonstrated that p33 binds to at least two distinct regions within LMT1. To the best of our knowledge, this is the first report of a plant virus protein binding to a lncRNA produced by the same virus. The biological significance of the interaction between these two viral factors is discussed.
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Affiliation(s)
- Sung-Hwan Kang
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA; (S.-H.K.); (V.A.)
| | - Vicken Aknadibossian
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA; (S.-H.K.); (V.A.)
| | - Laxmi Kharel
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA; (L.K.); (S.D.D.M.); (Y.W.)
| | | | - Ying Wang
- Department of Biological Sciences, Mississippi State University, Mississippi State, MS 39762, USA; (L.K.); (S.D.D.M.); (Y.W.)
| | - Svetlana Y. Folimonova
- Plant Pathology Department, University of Florida, Gainesville, FL 32611, USA; (S.-H.K.); (V.A.)
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4
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Navarro JA, Sanchez-Navarro JA, Pallas V. Key checkpoints in the movement of plant viruses through the host. Adv Virus Res 2019; 104:1-64. [PMID: 31439146 DOI: 10.1016/bs.aivir.2019.05.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Plant viruses cannot exploit any of the membrane fusion-based routes of entry described for animal viruses. In addition, one of the distinctive structures of plant cells, the cell wall, acts as the first barrier against the invasion of pathogens. To overcome the rigidity of the cell wall, plant viruses normally take advantage of the way of life of different biological vectors. Alternatively, the physical damage caused by environmental stresses can facilitate virus entry. Once inside the cell and taking advantage of the characteristic symplastic continuity of plant cells, viruses need to remodel and/or modify the restricted pore size of the plasmodesmata (channels that connect plant cells). In a successful interaction for the virus, it can reach the vascular tissue to systematically invade the plant. The connections between the different cell types in this path are not designed to allow the passage of molecules with the complexity of viruses. During this process, viruses face different cell barriers that must be overcome to reach the distal parts of the plant. In this review, we highlight the current knowledge about how plant RNA viruses enter plant cells, move between them to reach vascular cells and overcome the different physical and cellular barriers that the phloem imposes. Finally, we update the current research on cellular organelles as key regulator checkpoints in the long-distance movement of plant viruses.
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Affiliation(s)
- Jose A Navarro
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Jesus A Sanchez-Navarro
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Vicente Pallas
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain.
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5
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Kozieł E, Otulak-Kozieł K, Bujarski JJ. Ultrastructural Analysis of Prune DwarfVirus Intercellular Transport and Pathogenesis. Int J Mol Sci 2018; 19:E2570. [PMID: 30158483 PMCID: PMC6163902 DOI: 10.3390/ijms19092570] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 08/17/2018] [Accepted: 08/28/2018] [Indexed: 12/25/2022] Open
Abstract
Prune dwarf virus (PDV) is an important viral pathogen of plum, sweet cherry, peach, and many herbaceous test plants. Although PDV has been intensively investigated, mainly in the context of phylogenetic relationship of its genes and proteins, many gaps exist in our knowledge about the mechanism of intercellular transport of this virus. The aim of this work was to investigate alterations in cellular organelles and the cell-to-cell transport of PDV in Cucumis sativus cv. Polan at ultrastructural level. To analyze the role of viral proteins in local transport, double-immunogold assays were applied to localize PDV coat protein (CP) and movement protein (MP). We observe structural changes in chloroplasts, mitochondria, and cellular membranes. We prove that PDV is transported as viral particles via MP-generated tubular structures through plasmodesmata. Moreover, the computer-run 3D modeling reveals structural resemblances between MPs of PDV and of Alfalfa mosaic virus (AMV), implying similarities of transport mechanisms for both viruses.
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Affiliation(s)
- Edmund Kozieł
- Faculty of Agriculture and Biology, Department of Botany, Warsaw University of Life Sciences-SGGW, Nowoursynowska Street 159, 02-776 Warsaw, Poland.
| | - Katarzyna Otulak-Kozieł
- Faculty of Agriculture and Biology, Department of Botany, Warsaw University of Life Sciences-SGGW, Nowoursynowska Street 159, 02-776 Warsaw, Poland.
| | - Józef J Bujarski
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA.
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland.
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6
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Kozieł E, Bujarski JJ, Otulak K. Molecular Biology of Prune Dwarf Virus-A Lesser Known Member of the Bromoviridae but a Vital Component in the Dynamic Virus-Host Cell Interaction Network. Int J Mol Sci 2017; 18:E2733. [PMID: 29258199 PMCID: PMC5751334 DOI: 10.3390/ijms18122733] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 11/21/2017] [Accepted: 12/13/2017] [Indexed: 12/29/2022] Open
Abstract
Prune dwarf virus (PDV) is one of the members of Bromoviridae family, genus Ilarvirus. Host components that participate in the regulation of viral replication or cell-to-cell movement via plasmodesmata are still unknown. In contrast, viral infections caused by some other Bromoviridae members are well characterized. Bromoviridae can be distinguished based on localization of their replication process in infected cells, cell-to-cell movement mechanisms, and plant-specific response reactions. Depending upon the genus, "genome activation" and viral replication are linked to various membranous structures ranging from endoplasmic reticulum, to tonoplast. In the case of PDV, there is still no evidence of natural resistance sources in the host plants susceptible to virus infection. Apparently, PDV has a great ability to overcome the natural defense responses in a wide spectrum of plant hosts. The first manifestations of PDV infection are specific cell membrane alterations, and the formation of replicase complexes that support PDV RNA replication inside the spherules. During each stage of its life cycle, the virus uses cell components to replicate and to spread in whole plants, within the largely suppressed cellular immunity environment. This work presents the above stages of the PDV life cycle in the context of current knowledge about other Bromoviridae members.
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Affiliation(s)
- Edmund Kozieł
- Department of Botany, Faculty of Agriculture and Biology, Warsaw University of Life Sciences-SGGW, Nowoursynowska Street 159, 02-776 Warsaw, Poland.
| | - Józef J Bujarski
- Department of Biological Sciences, Northern Illinois University, DeKalb, IL 60115, USA.
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704 Poznań, Poland.
| | - Katarzyna Otulak
- Department of Botany, Faculty of Agriculture and Biology, Warsaw University of Life Sciences-SGGW, Nowoursynowska Street 159, 02-776 Warsaw, Poland.
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7
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Navarro B, Loconsole G, Giampetruzzi A, Aboughanem‐Sabanadzovic N, Ragozzino A, Ragozzino E, Di Serio F. Identification and characterization of privet leaf blotch-associated virus, a novel idaeovirus. MOLECULAR PLANT PATHOLOGY 2017; 18:925-936. [PMID: 27349357 PMCID: PMC6638295 DOI: 10.1111/mpp.12450] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2016] [Revised: 05/29/2016] [Accepted: 06/22/2016] [Indexed: 05/23/2023]
Abstract
A novel virus has been identified by next-generation sequencing (NGS) in privet (Ligustrum japonicum L.) affected by a graft-transmissible disease characterized by leaf blotch symptoms resembling infectious variegation, a virus-like privet disease with an unclear aetiology. This virus, which has been tentatively named 'privet leaf blotch-associated virus' (PrLBaV), was absent in non-symptomatic privet plants, as revealed by NGS and reverse transcription-polymerase chain reaction (RT-PCR). Molecular characterization of PrLBaV showed that it has a segmented genome composed of two positive single-stranded RNAs, one of which (RNA1) is monocistronic and codes for the viral replicase, whereas the other (RNA2) contains two open reading frames (ORFs), ORF2a and ORF2b, coding for the putative movement (p38) and coat (p30) proteins, respectively. ORF2b is very probably expressed through a subgenomic RNA starting with six nucleotides (AUAUCU) that closely resemble those found in the 5'-terminal end of genomic RNA1 and RNA2 (AUAUUU and AUAUAU, respectively). The molecular signatures identified in the PrLBaV RNAs and proteins resemble those of Raspberry bushy dwarf virus (RBDV), currently the only member of the genus Idaeovirus. These data, together with phylogenetic analyses, are consistent with the proposal of considering PrLBaV as a representative of the second species in the genus Idaeovirus. Transient expression of a recombinant PrLBaV p38 fused to green fluorescent protein in leaves of Nicotiana benthamiana, coupled with confocal laser scanning microscopy assays, showed that it localizes at cell plasmodesmata, strongly supporting its involvement in viral movement/trafficking and providing the first functional characterization of an idaeovirus encoded protein.
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Affiliation(s)
- Beatriz Navarro
- Istituto per la Protezione Sostenibile delle Piante CNR, UO BariVia Amendola 122/D, 70126 BariItaly
| | - Giuliana Loconsole
- Dipartimento di Scienze del Suolo, della Pianta e degli AlimentiUniversità degli Studi di Bari ‘Aldo Moro’Via Amendola 165/A, 70126 BariItaly
| | - Annalisa Giampetruzzi
- Dipartimento di Scienze del Suolo, della Pianta e degli AlimentiUniversità degli Studi di Bari ‘Aldo Moro’Via Amendola 165/A, 70126 BariItaly
| | | | - Antonio Ragozzino
- Dipartimento di AgrariaUniversità degli Studi di Napoli ‘Federico II’, Via Università100, 80055 PorticiItaly
| | - Ester Ragozzino
- Dipartimento di AgrariaUniversità degli Studi di Napoli ‘Federico II’, Via Università100, 80055 PorticiItaly
| | - Francesco Di Serio
- Istituto per la Protezione Sostenibile delle Piante CNR, UO BariVia Amendola 122/D, 70126 BariItaly
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8
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Peiro A, Izquierdo-Garcia AC, Sanchez-Navarro JA, Pallas V, Mulet JM, Aparicio F. Patellins 3 and 6, two members of the Plant Patellin family, interact with the movement protein of Alfalfa mosaic virus and interfere with viral movement. MOLECULAR PLANT PATHOLOGY 2014; 15:881-91. [PMID: 24751128 PMCID: PMC6638666 DOI: 10.1111/mpp.12146] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Movement proteins (MPs) encoded by plant viruses interact with host proteins to facilitate or interfere with intra- and/or intercellular viral movement. Using yeast two-hybrid and bimolecular fluorescence complementation assays, we herein present in vivo evidence for the interaction between Alfalfa mosaic virus (AMV) MP and Arabidopsis Patellin 3 (atPATL3) and Patellin 6 (atPATL6), two proteins containing a Sec14 domain. Proteins with Sec14 domains are implicated in membrane trafficking, cytoskeleton dynamics, lipid metabolism and lipid-mediated regulatory functions. Interestingly, the overexpression of atPATL3 and/or atPATL6 interfered with the plasmodesmata targeting of AMV MP and correlated with reduced infection foci size. Consistently, the viral RNA levels increased in the single and double Arabidopsis knockout mutants for atPATL3 and atPATL6. Our results indicate that, in general, MP-PATL interactions interfere with the correct subcellular targeting of MP, thus rendering the intracellular transport of viral MP-containing complexes less efficient and diminishing cell-to-cell movement.
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Affiliation(s)
- Ana Peiro
- Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Ingeniero Fausto Elio s/n, 46022, Valencia, Spain
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9
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Peiró A, Cañizares MC, Rubio L, López C, Moriones E, Aramburu J, Sánchez-Navarro J. The movement protein (NSm) of Tomato spotted wilt virus is the avirulence determinant in the tomato Sw-5 gene-based resistance. MOLECULAR PLANT PATHOLOGY 2014; 15:802-13. [PMID: 24690181 PMCID: PMC6638753 DOI: 10.1111/mpp.12142] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The avirulence determinant triggering the resistance conferred by the tomato gene Sw-5 against Tomato spotted wilt virus (TSWV) is still unresolved. Sequence comparison showed two substitutions (C118Y and T120N) in the movement protein NSm present only in TSWV resistance-breaking (RB) isolates. In this work, transient expression of NSm of three TSWV isolates [RB1 (T120N), RB2 (C118Y) and non-resistance-breaking (NRB)] in Nicotiana benthamiana expressing Sw-5 showed a hypersensitive response (HR) only with NRB. Exchange of the movement protein of Alfalfa mosaic virus (AMV) with NSm supported cell-to-cell and systemic transport of the chimeric AMV RNAs into N. tabacum with or without Sw-5, except for the constructs with NBR when Sw-5 was expressed, although RB2 showed reduced cell-to-cell transport. Mutational analysis revealed that N120 was sufficient to avoid the HR, but the substitution V130I was required for systemic transport. Finally, co-inoculation of RB and NRB AMV chimeric constructs showed different prevalence of RB or NBR depending on the presence or absence of Sw-5. These results indicate that NSm is the avirulence determinant for Sw-5 resistance, and mutations C118Y and T120N are responsible for resistance breakdown and have a fitness penalty in the context of the heterologous AMV system.
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Affiliation(s)
- Ana Peiró
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia, 46022, Valencia, Spain
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10
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Martínez C, Coll-Bonfill N, Aramburu J, Pallás V, Aparicio F, Galipienso L. Two basic (hydrophilic) regions in the movement protein of Parietaria mottle virus have RNA binding activity and are required for cell-to-cell transport. Virus Res 2014; 184:54-61. [PMID: 24583367 DOI: 10.1016/j.virusres.2014.02.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2014] [Revised: 02/07/2014] [Accepted: 02/12/2014] [Indexed: 11/29/2022]
Abstract
The movement protein (MP) of parietaria mottle virus (PMoV) is required for virus cell-to-cell movement. Bioinformatics analysis identified two hydrophilic non-contiguous regions (R1 and R2) rich in the basic amino acids lysine and arginine and with the predicted secondary structure of an α-helix. Different approaches were used to determine the implication of the R1 and R2 regions in RNA binding, plasmodesmata (PD) targeting and cell-to-cell movement. EMSA (Electrophoretic Mobility Shift Assay) showed that both regions have RNA-binding activity whereas that mutational analysis reported that either deletion of any of these regions, or loss of the basic amino acids, interfered with the viral intercellular movement. Subcellular localization studies showed that PMoV MP locates at PD. Mutants designed to impeded cell-to-cell movement failed to accumulate at PD indicating that basic residues in both R1 and R2 are critical for binding the MP at PD.
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Affiliation(s)
- Carolina Martínez
- Institut de Recerca i Tecnología Agroalimentaries (IRTA), Ctra. de Cabrils s/n Cabrils, 08348 Barcelona, Spain.
| | - Nuria Coll-Bonfill
- Institut D́investigacions Biomediques Agusti Pi i Sunyer, C/Rosselló 149-153, 08036 Barcelona, Spain.
| | - Jose Aramburu
- Institut de Recerca i Tecnología Agroalimentaries (IRTA), Ctra. de Cabrils s/n Cabrils, 08348 Barcelona, Spain.
| | - Vicente Pallás
- Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Ingeniero Fausto Elio s/n, 46022 Valencia, Spain.
| | - Frederic Aparicio
- Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Ingeniero Fausto Elio s/n, 46022 Valencia, Spain.
| | - Luis Galipienso
- Plant Pathology and Biotechnologies for Sustainable Agriculture Section, Euro-Mediterranean Institute of Science and Technology - I.E.ME.S.T., Via Emerico Amari 123, 90139 Palermo, Italy.
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11
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Hyodo K, Kaido M, Okuno T. Host and viral RNA-binding proteins involved in membrane targeting, replication and intercellular movement of plant RNA virus genomes. FRONTIERS IN PLANT SCIENCE 2014; 5:321. [PMID: 25071804 PMCID: PMC4083346 DOI: 10.3389/fpls.2014.00321] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2014] [Accepted: 06/18/2014] [Indexed: 05/10/2023]
Abstract
Many plant viruses have positive-strand RNA [(+)RNA] as their genome. Therefore, it is not surprising that RNA-binding proteins (RBPs) play important roles during (+)RNA virus infection in host plants. Increasing evidence demonstrates that viral and host RBPs play critical roles in multiple steps of the viral life cycle, including translation and replication of viral genomic RNAs, and their intra- and intercellular movement. Although studies focusing on the RNA-binding activities of viral and host proteins, and their associations with membrane targeting, and intercellular movement of viral genomes have been limited to a few viruses, these studies have provided important insights into the molecular mechanisms underlying the replication and movement of viral genomic RNAs. In this review, we briefly overview the currently defined roles of viral and host RBPs whose RNA-binding activity have been confirmed experimentally in association with their membrane targeting, and intercellular movement of plant RNA virus genomes.
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Affiliation(s)
| | | | - Tetsuro Okuno
- *Correspondence: Tetsuro Okuno, Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kitashirakawa, Sakyo-ku,Kyoto 606-8502, Japan e-mail:
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12
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The Tobacco mosaic virus movement protein associates with but does not integrate into biological membranes. J Virol 2013; 88:3016-26. [PMID: 24371064 DOI: 10.1128/jvi.03648-13] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
UNLABELLED Plant positive-strand RNA viruses require association with plant cell endomembranes for viral translation and replication, as well as for intra- and intercellular movement of the viral progeny. The membrane association and RNA binding of the Tobacco mosaic virus (TMV) movement protein (MP) are vital for orchestrating the macromolecular network required for virus movement. A previously proposed topological model suggests that TMV MP is an integral membrane protein with two putative α-helical transmembrane (TM) segments. Here we tested this model using an experimental system that measured the efficiency with which natural polypeptide segments were inserted into the ER membrane under conditions approximating the in vivo situation, as well as in planta. Our results demonstrated that the two hydrophobic regions (HRs) of TMV MP do not span biological membranes. We further found that mutations to alter the hydrophobicity of the first HR modified membrane association and precluded virus movement. We propose a topological model in which the TMV MP HRs intimately associate with the cellular membranes, allowing maximum exposure of the hydrophilic domains of the MP to the cytoplasmic cellular components. IMPORTANCE To facilitate plant viral infection and spread, viruses encode one or more movement proteins (MPs) that interact with ER membranes. The present work investigated the membrane association of the 30K MP of Tobacco mosaic virus (TMV), and the results challenge the previous topological model, which predicted that the TMV MP behaves as an integral membrane protein. The current data provide greatly needed clarification of the topological model and provide substantial evidence that TMV MP is membrane associated only at the cytoplasmic face of the membrane and that neither of its domains is integrated into the membrane or translocated into the lumen. Understanding the topology of MPs in the ER is vital for understanding the role of the ER in plant virus transport and for predicting interactions with host factors that mediate resistance to plant viruses.
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13
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Ruiz-Ruiz S, Soler N, Sánchez-Navarro J, Fagoaga C, López C, Navarro L, Moreno P, Peña L, Flores R. Citrus tristeza virus p23: determinants for nucleolar localization and their influence on suppression of RNA silencing and pathogenesis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2013; 26:306-18. [PMID: 23387469 DOI: 10.1094/mpmi-08-12-0201-r] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Citrus tristeza virus (CTV) encodes a singular protein (p23, 209 amino acids) with multiple functions, including RNA silencing suppression (RSS). Confocal laser-scanning microscopy of green fluorescent protein (GFP)-p23 agroexpressed in Nicotiana benthamiana revealed its accumulation in the nucleolus, Cajal bodies, and plasmodesmata. To dissect the nucleolar localization signal (NoLS) typically associated with basic motifs, seven truncated and 10 point-mutated versions of p23 were assayed. Deletion mutants showed that regions 50 to 86 and 100 to 157 (excluding fragment 106 to 114), both with basic motifs and the first with a zinc-finger, contain the (bipartite) NoLS. Alanine substitutions delimited this signal to three cysteines of the Zn-finger and some basic amino acids. RSS activity of p23 in N. benthamiana was abolished by essentially all mutants, indicating that it involves most p23 regions. The necrotic-inducing ability of p23 when launched in N. benthamiana from Potato virus X was only retained by deletion mutant 158-209 and one substitution mutant, showing that the Zn-finger and flanking basic motifs form part of the pathogenic determinant. Ectopic expression of p23 and some deletion mutants in transgenic Mexican lime demarcated a similar determinant, suggesting that p23 affects related pathways in citrus and N. benthamiana. Both RSS activity and pathogenicity of p23 appear related to its nucleolar localization.
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Affiliation(s)
- Susana Ruiz-Ruiz
- Consejo Superior de Investigaciones Cientificas-Universidad Politecnica de Valencia, Spain
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14
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Abstract
Ilarviruses were among the first 16 groups of plant viruses approved by ICTV. Like Alfalfa mosaic virus (AMV), bromoviruses, and cucumoviruses they are isometric viruses and possess a single-stranded, tripartite RNA genome. However, unlike these other three groups, ilarviruses were recognized as being recalcitrant subjects for research (their ready lability is reflected in the sigla used to create the group name) and were renowned as unpromising subjects for the production of antisera. However, it was recognized that they shared properties with AMV when the phenomenon of genome activation, in which the coat protein (CP) of the virus is required to be present to initiate infection, was demonstrated to cross group boundaries. The CP of AMV could activate the genome of an ilarvirus and vice versa. Development of the molecular information for ilarviruses lagged behind the knowledge available for the more extensively studied AMV, bromoviruses, and cucumoviruses. In the past 20 years, genomic data for most known ilarviruses have been developed facilitating their detection and allowing the factors involved in the molecular biology of the genus to be investigated. Much information has been obtained using Prunus necrotic ringspot virus and the more extensively studied AMV. A relationship between some ilarviruses and the cucumoviruses has been defined with the recognition that members of both genera encode a 2b protein involved in RNA silencing and long distance viral movement. Here, we present a review of the current knowledge of both the taxonomy and the molecular biology of this genus of agronomically and horticulturally important viruses.
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15
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Pallas V, Aparicio F, Herranz MC, Amari K, Sanchez-Pina MA, Myrta A, Sanchez-Navarro JA. Ilarviruses of Prunus spp.: a continued concern for fruit trees. PHYTOPATHOLOGY 2012; 102:1108-1120. [PMID: 23148725 DOI: 10.1094/phyto-02-12-0023-rvw] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Prunus spp. are affected by a large number of viruses, causing significant economic losses through either direct or indirect damage, which results in reduced yield and fruit quality. Among these viruses, members of the genus Ilarvirus (isometric labile ringspot viruses) occupy a significant position due to their distribution worldwide. Although symptoms caused by these types of viruses were reported early in the last century, their molecular characterization was not achieved until the 1990s, much later than for other agronomically relevant viruses. This was mainly due to the characteristic liability of virus particles in tissue extracts. In addition, ilarviruses, together with Alfalfa mosaic virus, are unique among plant viruses in that they require a few molecules of the coat protein in the inoculum in order to be infectious, a phenomenon known as genome activation. Another factor that has made the study of this group of viruses difficult is that infectious clones have been obtained only for the type member of the genus, Tobacco streak virus. Four ilarviruses, Prunus necrotic ringspot virus, Prune dwarf virus, Apple mosaic virus, and American plum line pattern virus, are pathogens of the main cultivated fruit trees. As stated in the 9th Report of the International Committee on Taxonomy of Viruses, virions of this genus are "unpromising subjects for the raising of good antisera." With the advent of molecular approaches for their detection and characterization, it has been possible to get a more precise view of their prevalence and genome organization. This review updates our knowledge on the incidence, genome organization and expression, genetic diversity, modes of transmission, and diagnosis, as well as control of this peculiar group of viruses affecting fruit trees.
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Affiliation(s)
- V Pallas
- Instituto de Biologia Celular y Molecular de Plantas, Universidad Politécnica de Valencia-Consejo, Spain.
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16
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Aparicio F, Aparicio-Sanchis R, Gadea J, Sánchez-Navarro JÁ, Pallás V, Murguía JR. A plant virus movement protein regulates the Gcn2p kinase in budding yeast. PLoS One 2011; 6:e27409. [PMID: 22087310 PMCID: PMC3210792 DOI: 10.1371/journal.pone.0027409] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Accepted: 10/17/2011] [Indexed: 11/19/2022] Open
Abstract
Virus life cycle heavily depends on their ability to command the host machinery in order to translate their genomes. Animal viruses have been shown to interfere with host translation machinery by expressing viral proteins that either maintain or inhibit eIF2α function by phosphorylation. However, this interference mechanism has not been described for any plant virus yet. Prunnus necrotic ringspot virus (PNRSV) is a serious pathogen of cultivated stone fruit trees. The movement protein (MP) of PNRSV is necessary for the cell-to-cell movement of the virus. By using a yeast-based approach we have found that over-expression of the PNRSV MP caused a severe growth defect in yeast cells. cDNA microarrays analysis carried out to characterise at the molecular level the growth interference phenotype reported the induction of genes related to amino acid deprivation suggesting that expression of MP activates the GCN pathway in yeast cells. Accordingly, PNRSV MP triggered activation of the Gcn2p kinase, as judged by increased eIF2α phosphorylation. Activation of Gcn2p by MP expression required a functional Tor1p kinase, since rapamycin treatment alleviated the yeast cell growth defect and blocked eIF2α phosphorylation triggered by MP expression. Overall, these findings uncover a previously uncharacterised function for PNRSV MP viral protein, and point out at Tor1p and Gcn2p kinases as candidate susceptibility factors for plant viral infections.
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Affiliation(s)
- Frederic Aparicio
- Department of Stress Biology, Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Valencia, Spain
| | - Rafael Aparicio-Sanchis
- Department of Stress Biology, Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Valencia, Spain
| | - José Gadea
- Department of Stress Biology, Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Valencia, Spain
| | - Jesús Ángel Sánchez-Navarro
- Department of Stress Biology, Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Valencia, Spain
| | - Vicente Pallás
- Department of Stress Biology, Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Valencia, Spain
| | - José Ramón Murguía
- Department of Stress Biology, Instituto de Biología Molecular y Celular de Plantas (UPV-CSIC), Valencia, Spain
- * E-mail:
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17
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Aparicio F, Pallás V, Sánchez-Navarro J. Implication of the C terminus of the Prunus necrotic ringspot virus movement protein in cell-to-cell transport and in its interaction with the coat protein. J Gen Virol 2010; 91:1865-70. [PMID: 20219894 DOI: 10.1099/vir.0.019950-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The movement protein (MP) of Prunus necrotic ringspot virus (PNRSV) is required for viral transport. Previous analysis with MPs of other members of the family Bromoviridae has shown that the C-terminal part of these MPs plays a critical role in the interaction with the cognate coat protein (CP) and in cell-to-cell transport. Bimolecular fluorescence complementation and overlay analysis confirm an interaction between the C-terminal 38 aa of PNRSV MP and its cognate CP. Mutational analysis of the C-terminal region of the PNRSV MP revealed that its C-terminal 38 aa are dispensable for virus transport, however, the 4 aa preceding the dispensable C terminus are necessary to target the MP to the plasmodesmata and for the functionality of the protein. The capacity of the PNRSV MP to use either a CP-dependent or a CP-independent cell-to-cell transport is discussed.
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Affiliation(s)
- Frederic Aparicio
- Instituto de Biología Molecular y Celular de Plantas, IBMCP (UPV-CSIC), Avenida Ingeniero Fausto Elio s/n, 46022 Valencia, Spain
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18
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Caulimoviridae tubule-guided transport is dictated by movement protein properties. J Virol 2010; 84:4109-12. [PMID: 20130061 DOI: 10.1128/jvi.02543-09] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Plant viruses move through plasmodesmata (PD) either as nucleoprotein complexes (NPCs) or as tubule-guided encapsidated particles with the help of movement proteins (MPs). To explore how and why MPs specialize in one mechanism or the other, we tested the exchangeability of MPs encoded by DNA and RNA virus genomes by means of an engineered alfalfa mosaic virus (AMV) system. We show that Caulimoviridae (DNA genome virus) MPs are competent for RNA virus particle transport but are unable to mediate NPC movement, and we discuss this restriction in terms of the evolution of DNA virus MPs as a means of mediating DNA viral genome entry into the RNA-trafficking PD pathway.
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19
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Genovés A, Navarro JA, Pallás V. A self-interacting carmovirus movement protein plays a role in binding of viral RNA during the cell-to-cell movement and shows an actin cytoskeleton dependent location in cell periphery. Virology 2009; 395:133-42. [PMID: 19796783 DOI: 10.1016/j.virol.2009.08.042] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 08/12/2009] [Accepted: 08/30/2009] [Indexed: 10/20/2022]
Abstract
The p7A of Melon necrotic spot virus has been described to be a RNA-binding movement protein essential for cell-to-cell movement but its role in this process is still unknown. Here, we found that primary and secondary structure elements on p7A appear to form a composite RNA-binding site required for both RNA interaction and cell-to-cell movement in plants indicating a direct correlation between these activities. Furthermore, we found that fluorescent-tagged p7A was distributed in punctuate structures at the cell periphery but also in motile cytoplasmic inclusion bodies which were in close association with the actin MFs and most likely generated by self-interacting p7A molecules as shown by BiFC assays. Consistently, the p7A subcellular distribution was revealed to be sensitive to the actin inhibitor, latrunculin B. The involvement of the RNA-binding capabilities and the subcellular location of the p7A in the intracellular and intercellular virus movement is discussed.
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Affiliation(s)
- Ainhoa Genovés
- Instituto de Biología Molecular y Celular de Plantas (IBMCP). UPV-CSIC, Avda. de los Naranjos s/n, Valencia, Spain.
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20
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Amari K, Burgos L, Pallás V, Sánchez-Pina MA. Vertical transmission of Prunus necrotic ringspot virus: hitch-hiking from gametes to seedling. J Gen Virol 2009; 90:1767-1774. [DOI: 10.1099/vir.0.009647-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The aim of this work was to follow Prunus necrotic ringspot virus (PNRSV) infection in apricot reproductive tissues and transmission of the virus to the next generation. For this, an analysis of viral distribution in apricot reproductive organs was carried out at different developmental stages. PNRSV was detected in reproductive tissues during gametogenesis. The virus was always present in the nucellus and, in some cases, in the embryo sac. Studies within infected seeds at the embryo globular stage revealed that PNRSV infects all parts of the seed, including embryo, endosperm and testa. In the torpedo and bent cotyledon developmental stages, high concentrations of the virus were detected in the testa and endosperm. At seed maturity, PNRSV accumulated slightly more in the embryo than in the cotyledons. In situ hybridization showed the presence of PNRSV RNA in embryos obtained following hand-pollination of virus-free pistils with infected pollen. Interestingly, tissue-printing from fruits obtained from these pistils showed viral RNA in the periphery of the fruits, whereas crosses between infected pistils and infected pollen resulted in a total invasion of the fruits. Taken together, these results shed light on the vertical transmission of PNRSV from gametes to seedlings.
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Affiliation(s)
- Khalid Amari
- Dpto. de Biología del Estrés y Patología Vegetal, CEBAS-CSIC, Campus Universitario de Espinardo, PO Box 164, 30010 Espinardo-Murcia, Spain
| | - Lorenzo Burgos
- Dpto. de Biología del Estrés y Patología Vegetal, CEBAS-CSIC, Campus Universitario de Espinardo, PO Box 164, 30010 Espinardo-Murcia, Spain
| | - Vicente Pallás
- Dpto. de Biología del Estrés y Patología Vegetal, CEBAS-CSIC, Campus Universitario de Espinardo, PO Box 164, 30010 Espinardo-Murcia, Spain
| | - Maria Amelia Sánchez-Pina
- Dpto. de Biología del Estrés y Patología Vegetal, CEBAS-CSIC, Campus Universitario de Espinardo, PO Box 164, 30010 Espinardo-Murcia, Spain
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21
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Plant virus cell-to-cell movement is not dependent on the transmembrane disposition of its movement protein. J Virol 2009; 83:5535-43. [PMID: 19321624 DOI: 10.1128/jvi.00393-09] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cell-to-cell transport of plant viruses depends on one or more virus-encoded movement proteins (MPs). Some MPs are integral membrane proteins that interact with the membrane of the endoplasmic reticulum, but a detailed understanding of the interaction between MPs and biological membranes has been lacking. The cell-to-cell movement of the Prunus necrotic ringspot virus (PNRSV) is facilitated by a single MP of the 30K superfamily. Here, using a myriad of biochemical and biophysical approaches, we show that the PNRSV MP contains only one hydrophobic region (HR) that interacts with the membrane interface, as opposed to being a transmembrane protein. We also show that a proline residue located in the middle of the HR constrains the structural conformation of this region at the membrane interface, and its replacement precludes virus movement.
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22
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Martínez-Turiño S, Hernández C. Inhibition of RNA silencing by the coat protein of Pelargonium flower break virus: distinctions from closely related suppressors. J Gen Virol 2009; 90:519-525. [DOI: 10.1099/vir.0.006098-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Viral-derived double-stranded RNAs (dsRNAs) activate RNA silencing, generating small interfering RNAs (siRNAs) which are incorporated into an RNA-induced silencing complex (RISC) that promotes homology-dependent degradation of cognate RNAs. To counteract this, plant viruses express RNA silencing suppressors. Here, we show that the coat protein (CP) of Pelargonium flower break virus (PFBV), a member of the genus Carmovirus, is able to efficiently inhibit RNA silencing. Interestingly, PFBV CP blocked both sense RNA- and dsRNA-triggered RNA silencing and did not preclude generation of siRNAs, which is in contrast with the abilities that have been reported for other carmoviral CPs. We have also found that PFBV CP can bind siRNAs and that this ability correlates with silencing suppression activity and enhancement of potato virus X pathogenicity. Collectively, the results indicate that PFBV CP inhibits RNA silencing by sequestering siRNAs and preventing their incorporation into a RISC, thus behaving similarly to unrelated viral suppressors but dissimilarly to orthologous ones.
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Affiliation(s)
- Sandra Martínez-Turiño
- Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-UPV), Avenida de los Naranjos, 46022 Valencia, Spain
| | - Carmen Hernández
- Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-UPV), Avenida de los Naranjos, 46022 Valencia, Spain
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23
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Sztuba-Solinska J, Bujarski JJ. Insights into the single-cell reproduction cycle of members of the family Bromoviridae: lessons from the use of protoplast systems. J Virol 2008; 82:10330-40. [PMID: 18684833 PMCID: PMC2573203 DOI: 10.1128/jvi.00746-08] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Affiliation(s)
- Joanna Sztuba-Solinska
- Department of Biological Sciences, Plant Molecular Biology Center, Montgomery Hall, Northern Illinois University, De Kalb, IL 60115, USA
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24
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Gosalvez-Bernal B, Genoves A, Navarro JA, Pallas V, Sanchez-Pina MA. Distribution and pathway for phloem-dependent movement of Melon necrotic spot virus in melon plants. MOLECULAR PLANT PATHOLOGY 2008; 9:447-61. [PMID: 18705860 PMCID: PMC6640420 DOI: 10.1111/j.1364-3703.2008.00474.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
The translocation of Melon necrotic spot virus (MNSV) within tissues of inoculated and systemically infected Cucumis melo L. 'Galia' was studied by tissue-printing and in situ hybridization techniques. The results were compatible with the phloem vascular components being used to spread MNSV systemically by the same assimilate transport route that runs from source to sink organs. Virus RNAs were shown to move from the inoculated cotyledon toward the hypocotyl and root system via the external phloem, whereas the upward spread through the stem to the young tissues took place via the internal phloem. Virus infection was absent from non-inoculated source tissues as well as from both shoot and root apical meristems, but active sink tissues such as the young leaves and root system were highly infected. Finally, our results suggest that the MNSV invasion of roots is due to virus replication although a destination-selective process is probably necessary to explain the high levels of virus accumulation in roots. This efficient invasion of the root system is discussed in terms of natural transmission of MNSV by the soil-borne fungal vector.
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Affiliation(s)
- Blanca Gosalvez-Bernal
- Departamento de Biología del Estrés y Patología Vegetal, CEBAS (CSIC), Campus Universitario de Espinardo, 30100, Murcia, Spain
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25
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Genetic diversity of the movement and coat protein genes of South American isolates of Prunus necrotic ringspot virus. Arch Virol 2008; 153:909-19. [PMID: 18365129 DOI: 10.1007/s00705-008-0066-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2007] [Accepted: 02/14/2008] [Indexed: 10/22/2022]
Abstract
Prunus necrotic ringspot virus (PNRSV) is distributed worldwide, but no molecular data have been previously reported from South American isolates. The nucleotide sequences corresponding to the movement (MP) and coat (CP) proteins of 23 isolates of PNRSV from Chile, Brazil, and Uruguay, and from different Prunus species, have been obtained. Phylogenetic analysis performed with full-length MP and CP sequences from all the PNRSV isolates confirmed the clustering of the isolates into the previously reported PV32-I, PV96-II and PE5-III phylogroups. No association was found between specific sequences and host, geographic origin or symptomatology. Comparative analysis showed that both MP and CP have phylogroup-specific amino acids and all of the motifs previously characterized for both proteins. The study of the distribution of synonymous and nonsynonymous changes along both open reading frames revealed that most amino acid sites are under the effect of negative purifying selection.
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26
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Herranz MC, Al Rwahnih M, Sánchez-Navarro JA, Elena SF, Choueiri E, Myrta A, Pallás V. Low genetic variability in the coat and movement proteins of American plum line pattern virus isolates from different geographic origins. Arch Virol 2007; 153:367-73. [DOI: 10.1007/s00705-007-1100-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Accepted: 10/29/2007] [Indexed: 11/30/2022]
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27
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Palani PV, Lin NS. Northern analysis of viral plus- and minus-strand RNAs. CURRENT PROTOCOLS IN MICROBIOLOGY 2007; Chapter 16:Unit 16E.3. [PMID: 18770617 DOI: 10.1002/9780471729259.mc16e03s4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Replication is a fundamental activity of viruses. Replication of positive-sense RNA viruses involves the synthesis of complementary minus-strand intermediates from the parental RNA template followed by synthesis of nascent plus strands. Negative-sense RNA genome and double-stranded RNA are copied into positive-sense mRNA before translation. To detect and estimate the abundance of plus- and minus-strand viral transcripts in the infected samples, northern analysis is the most commonly used method.
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Navarro JA, Genovés A, Climent J, Saurí A, Martínez-Gil L, Mingarro I, Pallás V. RNA-binding properties and membrane insertion of Melon necrotic spot virus (MNSV) double gene block movement proteins. Virology 2006; 356:57-67. [PMID: 16950492 DOI: 10.1016/j.virol.2006.07.040] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2006] [Revised: 05/01/2006] [Accepted: 07/06/2006] [Indexed: 11/22/2022]
Abstract
Advances in structural and biochemical properties of carmovirus movement proteins (MPs) have only been obtained in p7 and p9 from Carnation mottle virus (CarMV). Alignment of carmovirus MPs revealed a low conservation of amino acid identity but interestingly, similarity was elevated in regions associated with the functional secondary structure elements reported for CarMV which were conserved in all studied proteins. Nevertheless, some differential features in relation with CarMV MPs were identified in those from Melon necrotic virus (MNSV) (p7A and p7B). p7A was a soluble non-sequence specific RNA-binding protein, but unlike CarMV p7, its central region alone could not account for the RNA-binding properties of the entire protein. In fact, a 22-amino acid synthetic peptide whose sequence corresponds to this central region rendered an apparent dissociation constant (K(d)) significantly higher than that of the corresponding entire protein (9 mM vs. 0.83-25.7 microM). This p7A-derived peptide could be induced to fold into an alpha-helical structure as demonstrated for other carmovirus p7-like proteins. Additionally, in vitro fractionation of p7B transcription/translation mixtures in the presence of ER-derived microsomal membranes strongly suggested that p7B is an integral membrane protein. Both characteristics of these two small MPs forming the double gene block (DGB) of MNSV are discussed in the context of the intra- and intercellular movement of carmovirus.
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Affiliation(s)
- J A Navarro
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, Avenida de los Naranjos s/n, 46022 Valencia, Spain
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29
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Genovés A, Navarro JA, Pallás V. Functional analysis of the five melon necrotic spot virus genome-encoded proteins. J Gen Virol 2006; 87:2371-2380. [PMID: 16847133 DOI: 10.1099/vir.0.81793-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Function of the melon necrotic spot virus (MNSV) genome-encoded proteins (p29, p89, p7A, p7B and p42) has been studied. Protein-expression mutants of an infectious, full-length cDNA clone of a Spanish MNSV-Al isolate and a recombinant green fluorescent protein (GFP)-expressing virus were used in infection bioassays on melon plants. Results revealed that p29 and p89 are both essential for virus replication, whereas small proteins p7A and p7B are sufficient to support viral movement between adjacent cells operating in trans. It is also demonstrated that, in addition to its structural role as coat protein, p42 is an important factor controlling symptoms and is required for systemic transport. Moreover, both p42 and p7B, among all of the MNSV-encoded proteins, were able to delay RNA silencing in transient-expression assays on GFP-transgenic Nicotiana benthamiana plants. Finally, the presence of p42 also produced an enhancing effect on local spread similar to that of potyviral helper component proteinase (HC-Pro), probably due to its RNA silencing-suppression ability.
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Affiliation(s)
- A Genovés
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Avda de los Naranjos s/n, 46022 Valencia, Spain
| | - J A Navarro
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Avda de los Naranjos s/n, 46022 Valencia, Spain
| | - V Pallás
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), UPV-CSIC, Avda de los Naranjos s/n, 46022 Valencia, Spain
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30
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Codoñer FM, Fares MA, Elena SF. Adaptive covariation between the coat and movement proteins of prunus necrotic ringspot virus. J Virol 2006; 80:5833-40. [PMID: 16731922 PMCID: PMC1472603 DOI: 10.1128/jvi.00122-06] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The relative functional and/or structural importance of different amino acid sites in a protein can be assessed by evaluating the selective constraints to which they have been subjected during the course of evolution. Here we explore such constraints at the linear and three-dimensional levels for the movement protein (MP) and coat protein (CP) encoded by RNA 3 of prunus necrotic ringspot ilarvirus (PNRSV). By a maximum-parsimony approach, the nucleotide sequences from 46 isolates of PNRSV varying in symptomatology, host tree, and geographic origin have been analyzed and sites under different selective pressures have been identified in both proteins. We have also performed covariation analyses to explore whether changes in certain amino acid sites condition subsequent variation in other sites of the same protein or the other protein. These covariation analyses shed light on which particular amino acids should be involved in the physical and functional interaction between MP and CP. Finally, we discuss these findings in the light of what is already known about the implication of certain sites and domains in structure and protein-protein and RNA-protein interactions.
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Affiliation(s)
- Francisco M Codoñer
- Instituto de Biología Molecular y Celular de Plantas, Consejo Superior de Investigaciones Científicas-UPV, 46022 València, Spain
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Aparicio F, Sánchez-Navarro JA, Pallás V. In vitro and in vivo mapping of the Prunus necrotic ringspot virus coat protein C-terminal dimerization domain by bimolecular fluorescence complementation. J Gen Virol 2006; 87:1745-1750. [PMID: 16690941 DOI: 10.1099/vir.0.81696-0] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Interactions between viral proteins are critical for virus viability. Bimolecular fluorescent complementation (BiFC) technique determines protein interactions in real-time under almost normal physiological conditions. The coat protein (CP) of Prunus necrotic ringspot virus is required for multiple functions in its replication cycle. In this study, the region involved in CP dimerization has been mapped by BiFC in both bacteria and plant tissue. Full-length and C-terminal deleted forms of the CP gene were fused in-frame to the N- and C-terminal fragments of the yellow fluorescent protein. The BiFC analysis showed that a domain located between residues 9 and 27 from the C-end plays a critical role in dimerization. The importance of this C-terminal region in dimer formation and the applicability of the BiFC technique to analyse viral protein interactions are discussed.
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Affiliation(s)
- Frederic Aparicio
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia (CSIC), Av. de los Naranjos s/n, 46022 Valencia, Spain
| | - Jesús A Sánchez-Navarro
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia (CSIC), Av. de los Naranjos s/n, 46022 Valencia, Spain
| | - Vicente Pallás
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia (CSIC), Av. de los Naranjos s/n, 46022 Valencia, Spain
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Sánchez-Navarro JA, Carmen Herranz M, Pallás V. Cell-to-cell movement of Alfalfa mosaic virus can be mediated by the movement proteins of Ilar-, bromo-, cucumo-, tobamo- and comoviruses and does not require virion formation. Virology 2006; 346:66-73. [PMID: 16316673 DOI: 10.1016/j.virol.2005.10.024] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2005] [Revised: 06/29/2005] [Accepted: 10/07/2005] [Indexed: 11/29/2022]
Abstract
RNA 3 of Alfalfa mosaic virus (AMV) encodes the movement protein (MP) and coat protein (CP). Chimeric RNA 3 with the AMV MP gene replaced by the corresponding MP gene of Prunus necrotic ringspot virus, Brome mosaic virus, Cucumber mosaic virus or Cowpea mosaic virus efficiently moved from cell-to-cell only when the expressed MP was extended at its C-terminus with the C-terminal 44 amino acids of AMV MP. MP of Tobacco mosaic virus supported the movement of the chimeric RNA 3 whether or not the MP was extended with the C-terminal AMV MP sequence. The replacement of the CP gene in RNA 3 by a mutant gene encoding a CP defective in virion formation did not affect cell-to-cell transport of the chimera's with a functional MP. A GST pull-down technique was used to demonstrate for the first time that the C-terminal 44 amino acids of the MP of a virus belonging to the family Bromoviridae interact specifically with AMV virus particles. Together, these results demonstrate that AMV RNA 3 can be transported from cell-to-cell by both tubule-forming and non-tubule-forming MPs if a specific MP-CP interaction occurs.
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Affiliation(s)
- Jesús A Sánchez-Navarro
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, Av. de los Naranjos s/n, 46022 Valencia, Spain
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