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Marmisolle FE, Borniego MB, Cambiagno DA, Gonzalo L, García ML, Manavella PA, Hernández C, Reyes CA. Citrus psorosis virus 24K protein inhibits the processing of miRNA precursors by interacting with components of the biogenesis machinery. Microbiol Spectr 2024; 12:e0351323. [PMID: 38785434 PMCID: PMC11218507 DOI: 10.1128/spectrum.03513-23] [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: 10/31/2023] [Accepted: 04/22/2024] [Indexed: 05/25/2024] Open
Abstract
Sweet orange (Citrus sinensis) is one of the most important fruit crops worldwide. Virus infections in this crop can interfere with cellular processes, causing dramatic economic losses. By performing RT-qPCR analyses, we demonstrated that citrus psorosis virus (CPsV)-infected orange plants exhibited higher levels of unprocessed microRNA (miRNA) precursors than healthy plants. This result correlated with the reported reduction of mature miRNAs species. The protein 24K, the CPsV suppressor of RNA silencing (VSR), interacts with miRNA precursors in vivo. Thus, this protein becomes a candidate responsible for the increased accumulation of unprocessed miRNAs. We analyzed 24K RNA-binding and protein-protein interaction domains and described patterns of its subcellular localization. We also showed that 24K colocalizes within nuclear D-bodies with the miRNA biogenesis proteins DICER-LIKE 1 (DCL1), HYPONASTIC LEAVES 1 (HYL1), and SERRATE (SE). According to the results of bimolecular fluorescence complementation and co-immunoprecipitation assays, the 24K protein interacts with HYL1 and SE. Thus, 24K may inhibit miRNA processing in CPsV-infected citrus plants by direct interaction with the miRNA processing complex. This work contributes to the understanding of how a virus can alter the regulatory mechanisms of the host, particularly miRNA biogenesis and function.IMPORTANCESweet oranges can suffer from disease symptoms induced by virus infections, thus resulting in drastic economic losses. In sweet orange plants, CPsV alters the accumulation of some precursors from the regulatory molecules called miRNAs. This alteration leads to a decreased level of mature miRNA species. This misregulation may be due to a direct association of one of the viral proteins (24K) with miRNA precursors. On the other hand, 24K may act with components of the cell miRNA processing machinery through a series of predicted RNA-binding and protein-protein interaction domains.
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Affiliation(s)
- Facundo E. Marmisolle
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata, CONICET-UNLP, La Plata, Buenos Aires, Argentina
| | - María B. Borniego
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata, CONICET-UNLP, La Plata, Buenos Aires, Argentina
| | - Damián A. Cambiagno
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Lucia Gonzalo
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - María L. García
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata, CONICET-UNLP, La Plata, Buenos Aires, Argentina
| | - Pablo A. Manavella
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina
| | - Carmen Hernández
- Instituto de Biología Molecular y Celular de Plantas, CSIC-UPV, Valencia, Spain
| | - Carina A. Reyes
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata, CONICET-UNLP, La Plata, Buenos Aires, Argentina
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2
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Kaufholz F, Ulrich J, Hakeemi MS, Bucher G. Temporal control of RNAi reveals both robust and labile feedback loops in the segmentation clock of the red flour beetle. Proc Natl Acad Sci U S A 2024; 121:e2318229121. [PMID: 38865277 PMCID: PMC11194489 DOI: 10.1073/pnas.2318229121] [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: 10/19/2023] [Accepted: 05/03/2024] [Indexed: 06/14/2024] Open
Abstract
Animals from all major clades have evolved a segmented trunk, reflected in the human spine or the insect segments. These units emerge during embryogenesis from a posterior segment addition zone (SAZ), where repetitive gene activity is regulated by a mechanism described by the clock and wavefront/speed gradient model. In the red flour beetle Tribolium castaneum, RNA interference (RNAi) has been used to continuously knock down the function of primary pair-rule genes (pPRGs), caudal or Wnt pathway components, which has led to the complete breakdown of segmentation. However, it has remained untested, if this breakdown was reversible by bringing the missing gene function back to the system. To fill this gap, we established a transgenic system in T. castaneum, which allows blocking an ongoing RNAi effect with temporal control by expressing a viral inhibitor of RNAi via heat shock. We show that the T. castaneum segmentation machinery was able to reestablish after RNAi targeting the pPRGs Tc-eve, Tc-odd, and Tc-runt was blocked. However, we observed no rescue after blocking RNAi targeting Wnt pathway components. We conclude that the insect segmentation system contains both robust feedback loops that can reestablish and labile feedback loops that break down irreversibly. This combination may reconcile conflicting needs of the system: Labile systems controlling initiation and maintenance of the SAZ ensure that only one SAZ is formed. Robust feedback loops confer developmental robustness toward external disturbances.
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Affiliation(s)
- Felix Kaufholz
- Göttingen Graduate School for Neurosciences, Biophysics, and Molecular Biosciences, Göttingen37077, Germany
- Department of Evolutionary Developmental Genetics, University of Göttingen, Johann-Friedrich-Blumenbach Institute, Göttingen Center for Molecular Biosciences, Göttingen37077, Germany
| | - Julia Ulrich
- Department of Evolutionary Developmental Genetics, University of Göttingen, Johann-Friedrich-Blumenbach Institute, Göttingen Center for Molecular Biosciences, Göttingen37077, Germany
| | - Muhammad Salim Hakeemi
- Department of Evolutionary Developmental Genetics, University of Göttingen, Johann-Friedrich-Blumenbach Institute, Göttingen Center for Molecular Biosciences, Göttingen37077, Germany
| | - Gregor Bucher
- Department of Evolutionary Developmental Genetics, University of Göttingen, Johann-Friedrich-Blumenbach Institute, Göttingen Center for Molecular Biosciences, Göttingen37077, Germany
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Wu WC, Chen IH, Hou PY, Wang LH, Tsai CH, Cheng CP. The phosphorylation of the movement protein TGBp1 regulates the accumulation of the Bamboo mosaic virus. J Gen Virol 2024; 105. [PMID: 38189334 DOI: 10.1099/jgv.0.001945] [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: 01/09/2024] Open
Abstract
Phosphorylation and dephosphorylation of viral movement proteins plays a crucial role in regulating virus movement. Our study focused on investigating the movement protein TGBp1 of Bamboo mosaic virus (BaMV), which is a single-stranded positive-sense RNA virus. Specifically, we examined four potential phosphorylation sites (S15, S18, T58, and S247) within the TGBp1 protein. To study the impact of phosphorylation, we introduced amino acid substitutions at the selected sites. Alanine substitutions were used to prevent phosphorylation, while aspartate substitutions were employed to mimic phosphorylation. Our findings suggest that mimicking phosphorylation at S15, S18 and T58 of TGBp1 might be linked to silencing suppressor activities. The phosphorylated form at these sites exhibits a loss of silencing suppressor activity, leading to reduced viral accumulation in the inoculated leaves. Furthermore, mimicking phosphorylation at residues S15 and S18 could diminish viral accumulation at the single-cell level, while doing so at residue T58 could influence virus movement. However, mimicking phosphorylation at residue S247 does not appear to be relevant to both functions of TGBp1. Overall, our study provides insights into the functional significance of specific phosphorylation sites in BaMV TGBp1, illuminating the regulatory mechanisms involved in virus movement and silencing suppression.
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Affiliation(s)
- Wan-Chen Wu
- Department of Biomedical Sciences and Engineering, Tzu Chi University, Hualien, 970, Taiwan, ROC
| | - I-Hsuan Chen
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 402, Taiwan, ROC
- Advanced Plant and Food Crop Biotechnology Center, National Chung Hsing University, Taichung, 402, Taiwan, ROC
| | - Pei-Yu Hou
- Department of Biomedical Sciences and Engineering, Tzu Chi University, Hualien, 970, Taiwan, ROC
| | - Lan-Hui Wang
- Department of Biomedical Sciences and Engineering, Tzu Chi University, Hualien, 970, Taiwan, ROC
| | - Ching-Hsiu Tsai
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 402, Taiwan, ROC
- Advanced Plant and Food Crop Biotechnology Center, National Chung Hsing University, Taichung, 402, Taiwan, ROC
| | - Chi-Ping Cheng
- Department of Biomedical Sciences and Engineering, Tzu Chi University, Hualien, 970, Taiwan, ROC
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Chergintsev DA, Solovieva AD, Atabekova AK, Lezzhov AA, Golyshev SA, Morozov SY, Solovyev AG. Properties of Plant Virus Protein Encoded by the 5'-Proximal Gene of Tetra-Cistron Movement Block. Int J Mol Sci 2023; 24:14144. [PMID: 37762447 PMCID: PMC10532019 DOI: 10.3390/ijms241814144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 09/08/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
To move from cell to cell through plasmodesmata, many plant viruses require the concerted action of two or more movement proteins (MPs) encoded by transport gene modules of virus genomes. A tetra-cistron movement block (TCMB) is a newly discovered transport module comprising four genes. TCMB encodes three proteins, which are similar to MPs of the transport module known as the "triple gene block", and a protein unrelated to known viral MPs and containing a double-stranded RNA (dsRNA)-binding domain similar to that found in a family of cell proteins, including AtDRB4 and AtHYL1. Here, the latter TCMB protein, named vDRB for virus dsRNA-binding protein, is shown to bind both dsRNA and single-stranded RNA in vitro. In a turnip crinkle virus-based assay, vDRB exhibits the properties of a viral suppressor of RNA silencing (VSR). In the context of potato virus X infection, vDRB significantly decreases the number and size of "dark green islands", regions of local antiviral silencing, supporting the VSR function of vDRB. Nevertheless, vDRB does not exhibit the VSR properties in non-viral transient expression assays. Taken together, the data presented here indicate that vDRB is an RNA-binding protein exhibiting VSR functions in the context of viral infection.
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Affiliation(s)
- Denis A. Chergintsev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia; (D.A.C.); (A.K.A.); (A.A.L.); (S.A.G.); (S.Y.M.)
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia;
| | - Anna D. Solovieva
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia;
| | - Anastasia K. Atabekova
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia; (D.A.C.); (A.K.A.); (A.A.L.); (S.A.G.); (S.Y.M.)
| | - Alexander A. Lezzhov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia; (D.A.C.); (A.K.A.); (A.A.L.); (S.A.G.); (S.Y.M.)
| | - Sergei A. Golyshev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia; (D.A.C.); (A.K.A.); (A.A.L.); (S.A.G.); (S.Y.M.)
| | - Sergey Y. Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia; (D.A.C.); (A.K.A.); (A.A.L.); (S.A.G.); (S.Y.M.)
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia;
| | - Andrey G. Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia; (D.A.C.); (A.K.A.); (A.A.L.); (S.A.G.); (S.Y.M.)
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia;
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5
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Atabekova AK, Solovieva AD, Chergintsev DA, Solovyev AG, Morozov SY. Role of Plant Virus Movement Proteins in Suppression of Host RNAi Defense. Int J Mol Sci 2023; 24:ijms24109049. [PMID: 37240394 DOI: 10.3390/ijms24109049] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 05/18/2023] [Accepted: 05/19/2023] [Indexed: 05/28/2023] Open
Abstract
One of the systems of plant defense against viral infection is RNA silencing, or RNA interference (RNAi), in which small RNAs derived from viral genomic RNAs and/or mRNAs serve as guides to target an Argonaute nuclease (AGO) to virus-specific RNAs. Complementary base pairing between the small interfering RNA incorporated into the AGO-based protein complex and viral RNA results in the target cleavage or translational repression. As a counter-defensive strategy, viruses have evolved to acquire viral silencing suppressors (VSRs) to inhibit the host plant RNAi pathway. Plant virus VSR proteins use multiple mechanisms to inhibit silencing. VSRs are often multifunctional proteins that perform additional functions in the virus infection cycle, particularly, cell-to-cell movement, genome encapsidation, or replication. This paper summarizes the available data on the proteins with dual VSR/movement protein activity used by plant viruses of nine orders to override the protective silencing response and reviews the different molecular mechanisms employed by these proteins to suppress RNAi.
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Affiliation(s)
- Anastasia K Atabekova
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - Anna D Solovieva
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Denis A Chergintsev
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Andrey G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Sergey Y Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
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6
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Liao Q, Guo G, Lu R, Wang X, Du Z. Movement Protein Mediates Systemic Necrosis in Tomato Plants with Infection of Tomato Mosaic Virus. Viruses 2023; 15:157. [PMID: 36680197 PMCID: PMC9861833 DOI: 10.3390/v15010157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/02/2023] [Accepted: 01/03/2023] [Indexed: 01/06/2023] Open
Abstract
The necrogenic strain N5 of tomato mosaic virus (ToMV-N5) causes systemic necrosis in tomato cultivar Hezuo903. In this work, we mapped the viral determinant responsible for the induction of systemic necrosis. By exchanging viral genes between N5 and a non-necrogenic strain S1, we found that movement protein (MP) was the determinant for the differential symptoms caused by both strains. Compared with S1 MP, N5 MP had an additional ability to increase virus accumulation, which was not due to its functions in viral cell-to-cell movement. Actually, N5 MP, but not S1 MP, was a weak RNA silencing suppressor, which assisted viral accumulation. Sequence alignment showed that both MPs differed by only three amino acid residues. Experiments with viruses having mutated MPs indicated that the residue isoleucine at position 170 in MP was the key site for MP to increase virus accumulation, but also was required for MP to induce systemic necrosis in virus-infected tomato plants. Collectively, the lethal necrosis caused by N5 is dependent on its MP protein that enhances virus accumulation via its RNA silencing suppressor activity, probably leading to systemic necrosis responses in tomato plants.
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Affiliation(s)
- Qiansheng Liao
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
| | | | | | | | - Zhiyou Du
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
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7
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Alcaide C, Donaire L, Aranda MA. Transcriptome analyses unveiled differential regulation of AGO and DCL genes by pepino mosaic virus strains. MOLECULAR PLANT PATHOLOGY 2022; 23:1592-1607. [PMID: 35852033 PMCID: PMC9562736 DOI: 10.1111/mpp.13249] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Revised: 06/21/2022] [Accepted: 07/04/2022] [Indexed: 06/15/2023]
Abstract
Pepino mosaic virus (PepMV) is a single-stranded (ss), positive-sense (+) RNA potexvirus that affects tomato crops worldwide. We have described an in planta antagonistic interaction between PepMV isolates of two strains in which the EU isolate represses the accumulation of the CH2 isolate during mixed infections. Reports describing transcriptomic responses to mixed infections are scant. We carried out transcriptomic analyses of tomato plants singly and mixed-infected with two PepMV isolates of both strains. Comparison of the transcriptomes of singly infected plants showed that deeper transcriptomic alterations occurred at early infection times, and also that each of the viral strains modulated the host transcriptome differentially. Mixed infections caused transcriptomic alterations similar to those for the sum of single infections at early infection times, but clearly differing at later times postinfection. We next tested the hypothesis that PepMV-EU, in either single or mixed infections, deregulates host gene expression differentially so that virus accumulation of both strains gets repressed. That seemed to be the case for the genes AGO1a, DCL2d, AGO2a, and DCL2b, which are involved in the antiviral silencing pathway and were upregulated by PepMV-EU but not by PepMV-CH2 at early times postinfection. The pattern of AGO2a expression was validated by reverse transcription-quantitative PCR in tomato and Nicotiana benthamiana plants. Using an N. benthamiana ago2 mutant line, we showed that AGO2 indeed plays an important role in the antiviral defence against PepMV, but it is not the primary determinant of the outcome of the antagonistic interaction between the two PepMV strains.
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Affiliation(s)
- Cristina Alcaide
- Department of Stress Biology and Plant PathologyCentro de Edafología y Biología Aplicada del Segura‐CSICMurciaSpain
| | - Livia Donaire
- Department of Stress Biology and Plant PathologyCentro de Edafología y Biología Aplicada del Segura‐CSICMurciaSpain
| | - Miguel A. Aranda
- Department of Stress Biology and Plant PathologyCentro de Edafología y Biología Aplicada del Segura‐CSICMurciaSpain
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8
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Komatsu K, Hammond J. Plantago asiatica mosaic virus: An emerging plant virus causing necrosis in lilies and a new model RNA virus for molecular research. MOLECULAR PLANT PATHOLOGY 2022; 23:1401-1414. [PMID: 35856603 PMCID: PMC9452766 DOI: 10.1111/mpp.13243] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 06/01/2023]
Abstract
TAXONOMY Plantago asiatica mosaic virus belongs to the genus Potexvirus in the family Alphaflexiviridae of the order Tymovirales. VIRION AND GENOME PROPERTIES Plantago asiatica mosaic virus (PlAMV) has flexuous virions of approximately 490-530 nm in length and 10-15 nm in width. The genome of PlAMV consists of a single-stranded, positive-sense RNA of approximately 6.13 kb. It contains five open reading frames (ORFs 1-5), encoding a putative viral polymerase (RdRp), movement proteins (triple gene block proteins, TGBp1-3), and coat protein (CP), respectively. HOST RANGE PlAMV has an exceptionally wide host range and has been isolated from various wild plants, including Plantago asiatica, Nandina domestica, Rehmannia glutinosa, and other weed plants. Experimentally PlAMV can infect many plant species including Nicotiana benthamiana and Arabidopsis thaliana. It also infects ornamental lilies and frequently causes severe necrotic symptoms. However, host range varies depending on isolates, which show significant biological diversity within the species. GENOME DIVERSITY PlAMV can be separated into five clades based on phylogenetic analyses; nucleotide identities are significantly low between isolates in the different clades. TRANSMISSION PlAMV is not reported to be transmitted by biological vectors. Virions of PlAMV are quite stable and it can be transmitted efficiently by mechanical contact. DISEASE SYMPTOMS PlAMV causes red-rusted systemic necrosis in ornamental lilies, but it shows much weaker, if any, symptoms in wild plants such as P. asiatica. CONTROL Control of the disease caused by PlAMV is based mainly on rapid diagnosis and elimination of the infected bulbs or plants.
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Affiliation(s)
- Ken Komatsu
- Graduate School of AgricultureTokyo University of Agriculture and Technology (TUAT)FuchuJapan
| | - John Hammond
- US Department of AgricultureAgricultural Research Service (USDA‐ARS)BeltsvilleMarylandUSA
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9
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Solovyev AG, Atabekova AK, Lezzhov AA, Solovieva AD, Chergintsev DA, Morozov SY. Distinct Mechanisms of Endomembrane Reorganization Determine Dissimilar Transport Pathways in Plant RNA Viruses. PLANTS 2022; 11:plants11182403. [PMID: 36145804 PMCID: PMC9504206 DOI: 10.3390/plants11182403] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 08/02/2022] [Accepted: 09/13/2022] [Indexed: 11/22/2022]
Abstract
Plant viruses exploit the endomembrane system of infected cells for their replication and cell-to-cell transport. The replication of viral RNA genomes occurs in the cytoplasm in association with reorganized endomembrane compartments induced by virus-encoded proteins and is coupled with the virus intercellular transport via plasmodesmata that connect neighboring cells in plant tissues. The transport of virus genomes to and through plasmodesmata requires virus-encoded movement proteins (MPs). Distantly related plant viruses encode different MP sets, or virus transport systems, which vary in the number of MPs and their properties, suggesting their functional differences. Here, we discuss two distinct virus transport pathways based on either the modification of the endoplasmic reticulum tubules or the formation of motile vesicles detached from the endoplasmic reticulum and targeted to endosomes. The viruses with the movement proteins encoded by the triple gene block exemplify the first, and the potyviral system is the example of the second type. These transport systems use unrelated mechanisms of endomembrane reorganization. We emphasize that the mode of virus interaction with cell endomembranes determines the mechanism of plant virus cell-to-cell transport.
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Affiliation(s)
- Andrey G. Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
- All-Russia Research Institute of Agricultural Biotechnology, 127550 Moscow, Russia
| | - Anastasia K. Atabekova
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Alexander A. Lezzhov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
| | - Anna D. Solovieva
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Denis A. Chergintsev
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
| | - Sergey Y. Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, 119992 Moscow, Russia
- Department of Virology, Biological Faculty, Moscow State University, 119234 Moscow, Russia
- Correspondence: ; Tel.: +7-(495)-939-31-98
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Wang Y, Liu H, Wang Z, Guo Y, Hu T, Zhou X. P25 and P37 proteins encoded by firespike leafroll-associated virus are viral suppressors of RNA silencing. Front Microbiol 2022; 13:964156. [PMID: 36051767 PMCID: PMC9424829 DOI: 10.3389/fmicb.2022.964156] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/27/2022] [Indexed: 11/13/2022] Open
Abstract
Firespike leafroll-associated virus (FLRaV) is a major pathogen associated with firespike (Odontonema tubaeforme) leafroll disease. Phylogenetic analysis showed that FLRaV possesses typical traits of subgroup II members of ampeloviruses, but encodes two additional proteins, P25 and P37. Here, we determined the microfilament localization of P25 protein. Posttranscriptional gene silencing (PTGS) assay showed that both FLRaV P25 and P37 were able to suppress the local and systemic PTGS and FLRaV P25 was capable of suppressing the green fluorescent protein (GFP) gene silencing triggered by both sense RNA-induced PTGS (S-PTGS) and inverted repeat RNA-induced PTGS (IR-PTGS). In contrast, FLRaV P37 was only able to inhibit the GFP silencing triggered by the S-PTGS but not the IR-PTGS. In the transcriptional gene silencing (TGS) assay, only FLRaV P25 was found to be able to reverse established TGS-mediated silencing of GFP in 16-TGS plants. We also found that FLRaV P25 could aggravate the disease symptom and viral titer of potato virus X in N. benthamiana. These results suggest that FLRaV P25 and P37 may have crucial roles in overcoming host RNA silencing, which provides key insights into our understanding of the molecular mechanisms underlying FLRaV infection.
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Affiliation(s)
- Yaqin Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Hui Liu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Zhanqi Wang
- Key Laboratory of Vector Biology and Pathogen Control of Zhejiang Province, College of Life Sciences, Huzhou University, Huzhou, China
| | - Yushuang Guo
- Key Laboratory of Molecular Genetics, Guizhou Academy of Tobacco Science, Guiyang, China
| | - Tao Hu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- *Correspondence: Tao Hu,
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
- Xueping Zhou,
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Bioinformatic Analysis Predicts a Novel Genetic Module Related to Triple Gene and Binary Movement Blocks of Plant Viruses: Tetra-Cistron Movement Block. Biomolecules 2022; 12:biom12070861. [PMID: 35883420 PMCID: PMC9313169 DOI: 10.3390/biom12070861] [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: 05/27/2022] [Revised: 06/14/2022] [Accepted: 06/17/2022] [Indexed: 11/16/2022] Open
Abstract
Previous studies have shown that the RNA genomes of some plant viruses encode two related genetic modules required for virus movement over the host body, containing two or three genes and named the binary movement block (BMB) and triple gene block (TGB), respectively. In this paper, we predict a novel putative-related movement gene module, called the tetra-cistron movement block (TCMB), in the virus-like transcriptome assemblies of the moss Dicranum scoparium and the Antarctic flowering plant Colobanthus quitensis. These TCMBs are encoded by smaller RNA components of putative two-component viruses related to plant benyviruses. Similar to the RNA2 of benyviruses, TCMB-containing RNAs have the 5′-terminal coat protein gene and include the RNA helicase gene which is followed by two small overlapping cistrons encoding hydrophobic proteins with a distant sequence similarity to the TGB2 and TGB3 proteins. Unlike TGB, TCMB also includes a fourth 5′-terminal gene preceding the helicase gene and coding for a protein showing a similarity to the double-stranded RNA-binding proteins of the DSRM AtDRB-like superfamily. Additionally, based on phylogenetic analysis, we suggest the involvement of replicative beny-like helicases in the evolution of the BMB and TCMB movement genetic modules.
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Roles of RNA silencing in viral and non-viral plant immunity and in the crosstalk between disease resistance systems. Nat Rev Mol Cell Biol 2022; 23:645-662. [PMID: 35710830 DOI: 10.1038/s41580-022-00496-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/04/2022] [Indexed: 11/08/2022]
Abstract
RNA silencing is a well-established antiviral immunity system in plants, in which small RNAs guide Argonaute proteins to targets in viral RNA or DNA, resulting in virus repression. Virus-encoded suppressors of silencing counteract this defence system. In this Review, we discuss recent findings about antiviral RNA silencing, including the movement of RNA through plasmodesmata and the differentiation between plant self and viral RNAs. We also discuss the emerging role of RNA silencing in plant immunity against non-viral pathogens. This immunity is mediated by transkingdom movement of RNA into and out of the infected plant cells in vesicles or as extracellular nucleoproteins and, like antiviral immunity, is influenced by the silencing suppressors encoded in the pathogens' genomes. Another effect of RNA silencing on general immunity involves host-encoded small RNAs, including microRNAs, that regulate NOD-like receptors and defence signalling pathways in the innate immunity system of plants. These RNA silencing pathways form a network of processes with both positive and negative effects on the immune systems of plants.
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Beernink BM, Lappe RR, Bredow M, Whitham SA. Impacts of RNA Mobility Signals on Virus Induced Somatic and Germline Gene Editing. Front Genome Ed 2022; 4:925088. [PMID: 35755451 PMCID: PMC9219249 DOI: 10.3389/fgeed.2022.925088] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/16/2022] [Indexed: 11/13/2022] Open
Abstract
Viral vectors are being engineered to deliver CRISPR/Cas9 components systemically in plants to induce somatic or heritable site-specific mutations. It is hypothesized that RNA mobility signals facilitate entry of viruses or single guide RNAs (sgRNAs) into the shoot apical meristem where germline mutations can occur. Our objective was to understand the impact of RNA mobility signals on virus-induced somatic and germline gene editing in Nicotiana benthamiana and Zea mays. Previously, we showed that foxtail mosaic virus (FoMV) expressing sgRNA induced somatic mutations in N. benthamiana and Z. mays expressing Cas9. Here, we fused RNA mobility signals to sgRNAs targeting the genes encoding either N. benthamiana phytoene desaturase (PDS) or Z. mays high affinity potassium transporter 1 (HKT1). Addition of Arabidopsis thaliana Flowering Locus T (AtFT) and A. thaliana tRNA-Isoleucine (AttRNAIle) did not improve FoMV-induced somatic editing, and neither were sufficient to facilitate germline mutations in N. benthamiana. Maize FT homologs, Centroradialus 16 (ZCN16) and ZCN19, as well as AttRNAIle were found to aid somatic editing in maize but did not enable sgRNAs delivered by FoMV to induce germline mutations. Additional viral guide RNA delivery systems were assessed for somatic and germline mutations in N. benthamiana with the intention of gaining a better understanding of the specificity of mobile signal-facilitated germline editing. Potato virus X (PVX), barley stripe mosaic virus (BSMV), and tobacco rattle virus (TRV) were included in this comparative study, and all three of these viruses delivering sgRNA were able to induce somatic and germline mutations. Unexpectedly, PVX, a potexvirus closely related to FoMV, expressing sgRNA alone induced biallelic edited progeny, indicating that mobility signals are dispensable in virus-induced germline editing. These results show that PVX, BSMV, and TRV expressing sgRNA all have an innate ability to induce mutations in the germline. Our results indicate that mobility signals alone may not be sufficient to enable virus-based delivery of sgRNAs using the viruses, FoMV, PVX, BSMV, and TRV into cell types that result in germline mutations.
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Veselova SV, Sorokan AV, Burkhanova GF, Rumyantsev SD, Cherepanova EA, Alekseev VY, Sarvarova ER, Kasimova AR, Maksimov IV. By Modulating the Hormonal Balance and Ribonuclease Activity of Tomato Plants Bacillus subtilis Induces Defense Response against Potato Virus X and Potato Virus Y. Biomolecules 2022; 12:biom12020288. [PMID: 35204789 PMCID: PMC8961569 DOI: 10.3390/biom12020288] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/04/2022] [Accepted: 02/07/2022] [Indexed: 02/01/2023] Open
Abstract
Endophytic plant-growth-promoting microorganisms can protect plants against pathogens, but they have rarely been investigated as potential biocontrol agents and triggers of induced systemic resistance (ISR), regulated by phytohormones, against viruses. We studied the role of endophytic strains Bacillus subtilis 26D and B. subtilis Ttl2, which secrete ribonucleases and phytohormones, in the induction of tomato plant resistance against potato virus X and potato virus Y in a greenhouse condition. The endophytes reduced the accumulation of viruses in plants, increased the activity of plant ribonucleases and recovered the fruit yield of infected tomato plants. Both the 26D and Ttl2 strains induced ISR by activating the transcription of genes related to salicylate- and jasmonate-dependent responses. The 26D and Ttl2 strains increased the content of cytokinins and decreased the level of indolacetic acid in plants infected with PVX or PVY. PVY led to an increase of the abscisic acid (ABA) content in tomato plants, and PVX had the opposite effect. Both strains reduced the ABA content in plants infected with PVY and induced ABA accumulation in plants infected with PVX, which led to an increase in the resistance of plants. This is the first report of the protection of tomato plants against viral diseases by foliar application of endophytes.
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Clavel M, Lechner E, Incarbone M, Vincent T, Cognat V, Smirnova E, Lecorbeiller M, Brault V, Ziegler-Graff V, Genschik P. Atypical molecular features of RNA silencing against the phloem-restricted polerovirus TuYV. Nucleic Acids Res 2021; 49:11274-11293. [PMID: 34614168 PMCID: PMC8565345 DOI: 10.1093/nar/gkab802] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 08/25/2021] [Accepted: 10/04/2021] [Indexed: 11/12/2022] Open
Abstract
In plants and some animal lineages, RNA silencing is an efficient and adaptable defense mechanism against viruses. To counter it, viruses encode suppressor proteins that interfere with RNA silencing. Phloem-restricted viruses are spreading at an alarming rate and cause substantial reduction of crop yield, but how they interact with their hosts at the molecular level is still insufficiently understood. Here, we investigate the antiviral response against phloem-restricted turnip yellows virus (TuYV) in the model plant Arabidopsis thaliana. Using a combination of genetics, deep sequencing, and mechanical vasculature enrichment, we show that the main axis of silencing active against TuYV involves 22-nt vsiRNA production by DCL2, and their preferential loading into AGO1. Moreover, we identify vascular secondary siRNA produced from plant transcripts and initiated by DCL2-processed AGO1-loaded vsiRNA. Unexpectedly, and despite the viral encoded VSR P0 previously shown to mediate degradation of AGO proteins, vascular AGO1 undergoes specific post-translational stabilization during TuYV infection. Collectively, our work uncovers the complexity of antiviral RNA silencing against phloem-restricted TuYV and prompts a re-assessment of the role of its suppressor of silencing P0 during genuine infection.
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Affiliation(s)
- Marion Clavel
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Esther Lechner
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Marco Incarbone
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Timothée Vincent
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Valerie Cognat
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Ekaterina Smirnova
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Maxime Lecorbeiller
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | | | - Véronique Ziegler-Graff
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Pascal Genschik
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
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Niu E, Liu H, Zhou H, Luo L, Wu Y, Andika IB, Sun L. Autophagy Inhibits Intercellular Transport of Citrus Leaf Blotch Virus by Targeting Viral Movement Protein. Viruses 2021; 13:2189. [PMID: 34834995 PMCID: PMC8619118 DOI: 10.3390/v13112189] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 12/12/2022] Open
Abstract
Autophagy is an evolutionarily conserved cellular-degradation mechanism implicated in antiviral defense in plants. Studies have shown that autophagy suppresses virus accumulation in cells; however, it has not been reported to specifically inhibit viral spread in plants. This study demonstrated that infection with citrus leaf blotch virus (CLBV; genus Citrivirus, family Betaflexiviridae) activated autophagy in Nicotiana benthamiana plants as indicated by the increase of autophagosome formation. Impairment of autophagy through silencing of N. benthamiana autophagy-related gene 5 (NbATG5) and NbATG7 enhanced cell-to-cell and systemic movement of CLBV; however, it did not affect CLBV accumulation when the systemic infection had been fully established. Treatment using an autophagy inhibitor or silencing of NbATG5 and NbATG7 revealed that transiently expressed movement protein (MP), but not coat protein, of CLBV was targeted by selective autophagy for degradation. Moreover, we identified that CLBV MP directly interacted with NbATG8C1 and NbATG8i, the isoforms of autophagy-related protein 8 (ATG8), which are key factors that usually bind cargo receptors for selective autophagy. Our results present a novel example in which autophagy specifically targets a viral MP to limit the intercellular spread of the virus in plants.
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Affiliation(s)
- Erbo Niu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (E.N.); (H.Z.); (L.L.)
| | - Huan Liu
- School of Modern Agriculture and Biotechnology, Ankang University, Ankang 725000, China;
| | - Hongsheng Zhou
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (E.N.); (H.Z.); (L.L.)
| | - Lian Luo
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (E.N.); (H.Z.); (L.L.)
| | - Yunfeng Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (E.N.); (H.Z.); (L.L.)
| | - Ida Bagus Andika
- College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, China
| | - Liying Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (E.N.); (H.Z.); (L.L.)
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Bradamante G, Mittelsten Scheid O, Incarbone M. Under siege: virus control in plant meristems and progeny. THE PLANT CELL 2021; 33:2523-2537. [PMID: 34015140 PMCID: PMC8408453 DOI: 10.1093/plcell/koab140] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Accepted: 05/14/2021] [Indexed: 05/29/2023]
Abstract
In the arms race between plants and viruses, two frontiers have been utilized for decades to combat viral infections in agriculture. First, many pathogenic viruses are excluded from plant meristems, which allows the regeneration of virus-free plant material by tissue culture. Second, vertical transmission of viruses to the host progeny is often inefficient, thereby reducing the danger of viral transmission through seeds. Numerous reports point to the existence of tightly linked meristematic and transgenerational antiviral barriers that remain poorly understood. In this review, we summarize the current understanding of the molecular mechanisms that exclude viruses from plant stem cells and progeny. We also discuss the evidence connecting viral invasion of meristematic cells and the ability of plants to recover from acute infections. Research spanning decades performed on a variety of virus/host combinations has made clear that, beside morphological barriers, RNA interference (RNAi) plays a crucial role in preventing-or allowing-meristem invasion and vertical transmission. How a virus interacts with plant RNAi pathways in the meristem has profound effects on its symptomatology, persistence, replication rates, and, ultimately, entry into the host progeny.
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Affiliation(s)
- Gabriele Bradamante
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Ortrun Mittelsten Scheid
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Marco Incarbone
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
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18
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Kumar G, Dasgupta I. Variability, Functions and Interactions of Plant Virus Movement Proteins: What Do We Know So Far? Microorganisms 2021; 9:microorganisms9040695. [PMID: 33801711 PMCID: PMC8066623 DOI: 10.3390/microorganisms9040695] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/19/2021] [Accepted: 03/22/2021] [Indexed: 12/12/2022] Open
Abstract
Of the various proteins encoded by plant viruses, one of the most interesting is the movement protein (MP). MPs are unique to plant viruses and show surprising structural and functional variability while maintaining their core function, which is to facilitate the intercellular transport of viruses or viral nucleoprotein complexes. MPs interact with components of the intercellular channels, the plasmodesmata (PD), modifying their size exclusion limits and thus allowing larger particles, including virions, to pass through. The interaction of MPs with the components of PD, the formation of transport complexes and the recruitment of host cellular components have all revealed different facets of their functions. Multitasking is an inherent property of most viral proteins, and MPs are no exception. Some MPs carry out multitasking, which includes gene silencing suppression, viral replication and modulation of host protein turnover machinery. This review brings together the current knowledge on MPs, focusing on their structural variability, various functions and interactions with host proteins.
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19
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Chen AYS, Peng JHC, Polek M, Tian T, Ludman M, Fátyol K, Ng JCK. Comparative analysis identifies amino acids critical for citrus tristeza virus (T36CA) encoded proteins involved in suppression of RNA silencing and differential systemic infection in two plant species. MOLECULAR PLANT PATHOLOGY 2021; 22:64-76. [PMID: 33118689 PMCID: PMC7749750 DOI: 10.1111/mpp.13008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 09/05/2020] [Accepted: 09/22/2020] [Indexed: 05/06/2023]
Abstract
Complementary (c)DNA clones corresponding to the full-length genome of T36CA (a Californian isolate of Citrus tristeza virus with the T36 genotype), which shares 99.1% identity with that of T36FL (a T36 isolate from Florida), were made into a vector system to express the green fluorescent protein (GFP). Agroinfiltration of two prototype T36CA-based vectors (pT36CA) to Nicotiana benthamiana plants resulted in local but not systemic GFP expression/viral infection. This contrasted with agroinfiltration of the T36FL-based vector (pT36FL), which resulted in both local and systemic GFP expression/viral infection. A prototype T36CA systemically infected RNA silencing-defective N. benthamiana lines, demonstrating that a genetic basis for its defective systemic infection was RNA silencing. We evaluated the in planta bioactivity of chimeric pT36CA-pT36FL constructs and the results suggested that nucleotide variants in several open reading frames of the prototype T36CA could be responsible for its defective systemic infection. A single amino acid substitution in each of two silencing suppressors, p20 (S107G) and p25 (G36D), of prototype T36CA facilitated its systemic infectivity in N. benthamiana (albeit with reduced titre relative to that of T36FL) but not in Citrus macrophylla plants. Enhanced virus accumulation and, remarkably, robust systemic infection of T36CA in N. benthamiana and C. macrophylla plants, respectively, required two additional amino acid substitutions engineered in p65 (N118S and S158L), a putative closterovirus movement protein. The availability of pT36CA provides a unique opportunity for comparative analysis to identify viral coding and noncoding nucleotides or sequences involved in functions that are vital for in planta infection.
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Affiliation(s)
- Angel Y. S. Chen
- Department of Microbiology and Plant PathologyUniversity of CaliforniaRiversideCaliforniaUSA
| | - James H. C. Peng
- Department of Microbiology and Plant PathologyUniversity of CaliforniaRiversideCaliforniaUSA
| | - MaryLou Polek
- National Clonal Germplasm Repository for Citrus & DatesUSDA ARSRiversideCaliforniaUSA
| | - Tongyan Tian
- California Department of Food and AgricultureSacramentoCaliforniaUSA
| | - Márta Ludman
- Agricultural Biotechnology InstituteNational Research and Innovation CenterHungary
| | - Károly Fátyol
- Agricultural Biotechnology InstituteNational Research and Innovation CenterHungary
| | - James C. K. Ng
- Department of Microbiology and Plant PathologyUniversity of CaliforniaRiversideCaliforniaUSA
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Zhang S, Huang A, Zhou X, Li Z, Dietzgen RG, Zhou C, Cao M. Natural Defect of a Plant Rhabdovirus Glycoprotein Gene: A Case Study of Virus-Plant Coevolution. PHYTOPATHOLOGY 2021; 111:227-236. [PMID: 32648524 DOI: 10.1094/phyto-05-20-0191-fi] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Seven isolates of a putative cytorhabdovirus (family Rhabdoviridae, order Mononegavirales) designated as citrus-associated rhabdovirus (CiaRV) were identified in citrus, passion fruit, and paper bush from the same geographical area in China. CiaRV, bean-associated cytorhabdovirus (Brazil), and papaya virus E (Ecuador) should be taxonomically classified in the species Papaya cytorhabdovirus. Due to natural mutations, the glycoprotein (G) and P4 genes were impaired in citrus-infecting isolates of CiaRV, resulting in an atypical rhabdovirus genome organization of 3' leader-N-P-P3-M-L-5' trailer. The P3 protein of CiaRV shared a common origin with begomoviral movement proteins (family Geminiviridae). Secondary structure analysis and trans-complementation of movement-deficient tomato mosaic virus and potato virus X mutants by CiaRV P3 supported its function in viral cell-to-cell trafficking. The wide geographical dispersal of CiaRV and related viruses suggests an efficient transmission mechanism, as well as an underlying risk to global agriculture. Both the natural phenomenon and experimental analyses demonstrated presence of the "degraded" type of CiaRV in citrus, in parallel to "undegraded" types in other host plant species. This case study shows a plant virus losing the function of an important but nonessential gene, likely due to host shift and adaption, which deepened our understanding of course of natural viral diversification.
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Affiliation(s)
- Song Zhang
- National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China
- Academy of Agricultural Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Aijun Huang
- National Navel Orange Research Center, College of Life Science, Gannan Normal University, Ganzhou, China
| | - Xin Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Zhenghe Li
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, Zhejiang, China
| | - Ralf G Dietzgen
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Changyong Zhou
- National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China
- Academy of Agricultural Sciences, Southwest University, Beibei, Chongqing 400715, China
| | - Mengji Cao
- National Citrus Engineering and Technology Research Center, Citrus Research Institute, Southwest University, Beibei, Chongqing 400712, China
- Academy of Agricultural Sciences, Southwest University, Beibei, Chongqing 400715, China
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Hammond J, Reinsel M, Grinstead S, Lockhart B, Jordan R, Mollov D. A Mixed Infection of Helenium Virus S With Two Distinct Isolates of Butterbur Mosaic Virus, One of Which Has a Major Deletion in an Essential Gene. Front Microbiol 2020; 11:612936. [PMID: 33408710 PMCID: PMC7779399 DOI: 10.3389/fmicb.2020.612936] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Accepted: 11/27/2020] [Indexed: 11/16/2022] Open
Abstract
Multiple carlaviruses infect various ornamental plants, often having limited host ranges and causing minor symptoms, yet often reducing yield or quality. In this study we have identified a mixed infection of butterbur mosaic virus (ButMV) and helenium virus S (HelVS) from a plant of veronica (Veronica sp.) showing foliar mosaic and distortion. Carlavirus-like particles were observed by transmission electron microscopy (TEM), and RNA from partially purified virions was amplified by random RT-PCR, yielding clones of 439–1,385 bp. Two partially overlapping clones including coat protein (CP) sequence, and two of four partial replicase clones, were closely related to ButMV-J (AB517596), previously reported only from butterbur (Petasites japonicus) in Japan. Two other partial replicase clones showed lower identity to multiple carlaviruses. Generic primers which amplify the 3′-terminal region of multiple carlaviruses yielded clones of three distinct sequences: (1) with 98% nt identity to HelVS; (2) ButMV-A, showing 82% nt identity to ButMV-J; and (3) ButMV-B, with 78% nt identity to each of ButMV-J and ButMV-A. Further amplification of upstream fragments revealed that ButMV-B had an internal deletion in TGB1, confirmed using isolate-specific primers. Near-complete genomes of both ButMV-A and ButMV-B were obtained from next-generation sequencing (NGS), confirming the deletion within ButMV-B, which is presumably maintained through complementation by ButMV-A. HelVS was previously reported only from Helenium hybrids and Impatiens holstii. A near-complete HelVS genome was obtained for the first time by NGS from the same sample. Additional Veronica hybrids infected with HelVS were identified by TEM and RT-PCR, including cv. ‘Sunny Border Blue’ which was also subjected to NGS. This resulted in assembly of an 8,615 nt near-complete HelVS genome, with high identity to that from the mixed infection. The predicted CP sequence has 96% amino acid (aa) identity to HelVS from helenium (Q00556). Other ORFs show a maximum of 54% (TGB3) to 68% (NABP) aa identity to the equivalent ORFs of other carlaviruses. These results demonstrate for the first time maintenance by complementation of a carlavirus isolate with a major deletion in an essential gene, and confirm that HelVS is a distinct species in the genus Carlavirus.
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Affiliation(s)
- John Hammond
- Floral and Nursery Plants Research Unit, United States National Arboretum, United States Department of Agriculture-Agricultural Research Service, Beltsville, MD, United States
| | - Michael Reinsel
- Floral and Nursery Plants Research Unit, United States National Arboretum, United States Department of Agriculture-Agricultural Research Service, Beltsville, MD, United States
| | - Samuel Grinstead
- National Germplasm Resources Laboratory, Beltsville Agricultural Research Center, United States Department of Agriculture-Agricultural Research Service, Beltsville, MD, United States
| | - Ben Lockhart
- Department of Plant Pathology, University of Minnesota, St. Paul, MN, United States
| | - Ramon Jordan
- Floral and Nursery Plants Research Unit, United States National Arboretum, United States Department of Agriculture-Agricultural Research Service, Beltsville, MD, United States
| | - Dimitre Mollov
- National Germplasm Resources Laboratory, Beltsville Agricultural Research Center, United States Department of Agriculture-Agricultural Research Service, Beltsville, MD, United States
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22
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Morozov SY, Solovyev AG. Small hydrophobic viral proteins involved in intercellular movement of diverse plant virus genomes. AIMS Microbiol 2020; 6:305-329. [PMID: 33134746 PMCID: PMC7595835 DOI: 10.3934/microbiol.2020019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 09/13/2020] [Indexed: 12/12/2022] Open
Abstract
Most plant viruses code for movement proteins (MPs) targeting plasmodesmata to enable cell-to-cell and systemic spread in infected plants. Small membrane-embedded MPs have been first identified in two viral transport gene modules, triple gene block (TGB) coding for an RNA-binding helicase TGB1 and two small hydrophobic proteins TGB2 and TGB3 and double gene block (DGB) encoding two small polypeptides representing an RNA-binding protein and a membrane protein. These findings indicated that movement gene modules composed of two or more cistrons may encode the nucleic acid-binding protein and at least one membrane-bound movement protein. The same rule was revealed for small DNA-containing plant viruses, namely, viruses belonging to genus Mastrevirus (family Geminiviridae) and the family Nanoviridae. In multi-component transport modules the nucleic acid-binding MP can be viral capsid protein(s), as in RNA-containing viruses of the families Closteroviridae and Potyviridae. However, membrane proteins are always found among MPs of these multicomponent viral transport systems. Moreover, it was found that small membrane MPs encoded by many viruses can be involved in coupling viral replication and cell-to-cell movement. Currently, the studies of evolutionary origin and functioning of small membrane MPs is regarded as an important pre-requisite for understanding of the evolution of the existing plant virus transport systems. This paper represents the first comprehensive review which describes the whole diversity of small membrane MPs and presents the current views on their role in plant virus movement.
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Affiliation(s)
- Sergey Y Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.,Department of Virology, Biological Faculty, Moscow State University, Moscow, Russia
| | - Andrey G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.,Department of Virology, Biological Faculty, Moscow State University, Moscow, Russia.,Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
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Klap C, Luria N, Smith E, Hadad L, Bakelman E, Sela N, Belausov E, Lachman O, Leibman D, Dombrovsky A. Tomato Brown Rugose Fruit Virus Contributes to Enhanced Pepino Mosaic Virus Titers in Tomato Plants. Viruses 2020; 12:v12080879. [PMID: 32796777 PMCID: PMC7472245 DOI: 10.3390/v12080879] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 08/09/2020] [Accepted: 08/10/2020] [Indexed: 12/19/2022] Open
Abstract
The tobamovirus tomato brown rugose fruit virus (ToBRFV), a major threat to tomato production worldwide, has recently been documented in mixed infections with the potexvirus pepino mosaic virus (PepMV) CH2 strain in traded tomatoes in Israel. A study of greenhouse tomato plants in Israel revealed severe new viral disease symptoms including open unripe fruits and yellow patched leaves. PepMV was only detected in mixed infections with ToBRFV in all 104 tested sites, using serological and molecular analyses. Six PepMV isolates were identified, all had predicted amino acids characteristic of CH2 mild strains excluding an isoleucine at amino acid position 995 of the replicase. High-throughput sequencing of viral RNA extracted from four selected symptomatic plants showed solely the ToBRFV and PepMV, with total aligned read ratios of 40.61% and 11.73%, respectively, indicating prevalence of the viruses. Analyses of interactions between the co-infecting viruses by sequential and mixed viral inoculations of tomato plants, at various temperatures, showed a prominent increase in PepMV titers in ToBRFV pre-inoculated plants and in mixed-infected plants at 18–25 °C, compared to PepMV-single inoculations, as analyzed by Western blot and quantitative RT-PCR tests. These results suggest that Israeli mild PepMV isolate infections, preceded by ToBRFV, could induce symptoms characteristic of PepMV aggressive strains.
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Affiliation(s)
- Chen Klap
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel; (C.K.); (N.L.); (E.S.); (L.H.); (E.B.); (N.S.); (O.L.); (D.L.)
- The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 761001, Israel
| | - Neta Luria
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel; (C.K.); (N.L.); (E.S.); (L.H.); (E.B.); (N.S.); (O.L.); (D.L.)
| | - Elisheva Smith
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel; (C.K.); (N.L.); (E.S.); (L.H.); (E.B.); (N.S.); (O.L.); (D.L.)
| | - Lior Hadad
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel; (C.K.); (N.L.); (E.S.); (L.H.); (E.B.); (N.S.); (O.L.); (D.L.)
- The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 761001, Israel
| | - Elena Bakelman
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel; (C.K.); (N.L.); (E.S.); (L.H.); (E.B.); (N.S.); (O.L.); (D.L.)
| | - Noa Sela
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel; (C.K.); (N.L.); (E.S.); (L.H.); (E.B.); (N.S.); (O.L.); (D.L.)
| | - Eduard Belausov
- Department of Ornamental Plants and Agricultural Biotechnology, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel;
| | - Oded Lachman
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel; (C.K.); (N.L.); (E.S.); (L.H.); (E.B.); (N.S.); (O.L.); (D.L.)
| | - Diana Leibman
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel; (C.K.); (N.L.); (E.S.); (L.H.); (E.B.); (N.S.); (O.L.); (D.L.)
| | - Aviv Dombrovsky
- Department of Plant Pathology and Weed Research, Agricultural Research Organization, The Volcani Center, 68 HaMaccabim Road, P.O.B 15159, Rishon LeZion 7505101, Israel; (C.K.); (N.L.); (E.S.); (L.H.); (E.B.); (N.S.); (O.L.); (D.L.)
- Correspondence: ; Tel.: +972-3-968-3579; Fax: +972-3-968-6543
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Jiang Z, Zhang K, Li Z, Li Z, Yang M, Jin X, Cao Q, Wang X, Yue N, Li D, Zhang Y. The Barley stripe mosaic virus γb protein promotes viral cell-to-cell movement by enhancing ATPase-mediated assembly of ribonucleoprotein movement complexes. PLoS Pathog 2020; 16:e1008709. [PMID: 32730331 PMCID: PMC7419011 DOI: 10.1371/journal.ppat.1008709] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2020] [Revised: 08/11/2020] [Accepted: 06/17/2020] [Indexed: 02/07/2023] Open
Abstract
Nine genera of viruses in five different families use triple gene block (TGB) proteins for virus movement. The TGB modules fall into two classes: hordei-like and potex-like. Although TGB-mediated viral movement has been extensively studied, determination of the constituents of the viral ribonucleoprotein (vRNP) movement complexes and the mechanisms underlying their involvement in vRNP-mediated movement are far from complete. In the current study, immunoprecipitation of TGB1 protein complexes formed during Barley stripe mosaic virus (BSMV) infection revealed the presence of the γb protein in the products. Further experiments demonstrated that TGB1 interacts with γb in vitro and in vivo, and that γb-TGB1 localizes at the periphery of chloroplasts and plasmodesmata (PD). Subcellular localization analyses of the γb protein in Nicotiana benthamiana epidermal cells indicated that in addition to chloroplast localization, γb also targets the ER, actin filaments and PD at different stages of viral infection. By tracking γb localization during BSMV infection, we demonstrated that γb is required for efficient cell-to-cell movement. The N-terminus of γb interacts with the TGB1 ATPase/helicase domain and enhances ATPase activity of the domain. Inactivation of the TGB1 ATPase activity also significantly impaired PD targeting. In vitro translation together with co-immunoprecipitation (co-IP) analyses revealed that TGB1-TGB3-TGB2 complex formation is enhanced by ATP hydrolysis. The γb protein positively regulates complex formation in the presence of ATP, suggesting that γb has a novel role in BSMV cell-to-cell movement by directly promoting TGB1 ATPase-mediated vRNP movement complex assembly. We further demonstrated that elimination of ATPase activity abrogates PD and actin targeting of Potato virus X (PVX) and Beet necrotic yellow vein virus (BNYVV) TGB1 proteins. These results expand our understanding of the multifunctional roles of γb and provide new insight into the functions of TGB1 ATPase domains in the movement of TGB-encoding viruses.
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Affiliation(s)
- Zhihao Jiang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Kun Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Zhaolei Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Zhenggang Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Meng Yang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Xuejiao Jin
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Qing Cao
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Xueting Wang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Ning Yue
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Dawei Li
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
| | - Yongliang Zhang
- State Key Laboratory of Agro-Biotechnology and Ministry of Agriculture Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, P. R. China
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Brosseau C, Bolaji A, Roussin-Léveillée C, Zhao Z, Biga S, Moffett P. Natural variation in the Arabidopsis AGO2 gene is associated with susceptibility to potato virus X. THE NEW PHYTOLOGIST 2020; 226:866-878. [PMID: 31880814 DOI: 10.1111/nph.16397] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 12/12/2019] [Indexed: 06/10/2023]
Abstract
RNA silencing functions as an anti-viral defence in plants through the action of DICER-like (DCL) and ARGONAUTE (AGO) proteins. Despite the importance of this mechanism, little is known about the functional consequences of variation in genes encoding RNA silencing components. The AGO2 protein has been shown to be important for defense against multiple viruses, and we investigated how naturally occurring differences in AGO2 between and within species affects its antiviral activities. We find that the AGO2 protein from Arabidopsis thaliana, but not Nicotiana benthamiana, effectively limits potato virus X (PVX). Consistent with this, we find that the A. thaliana AGO2 gene shows a high incidence of polymorphisms between accessions, with evidence of selective pressure. Using functional analyses, we identify polymorphisms that specifically affect AGO2 antiviral activity, without interfering with other AGO2-associated functions such as anti-bacterial resistance or DNA methylation. Our results suggest that viruses adapt to overcome RNA silencing in their hosts. Furthermore, they indicate that plant-virus interactions have influenced natural variation in RNA-silencing components and that the latter may be a source of genetically encoded virus resistance.
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Affiliation(s)
- Chantal Brosseau
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Ayooluwa Bolaji
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | | | - Zhenxing Zhao
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Sébastien Biga
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
| | - Peter Moffett
- Département de Biologie, Centre SÈVE, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada
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26
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Meena RP, Prabha K, Baranwal VK. Genome characterization of citrus yellow vein-clearing virus: limited heterogeneity of viral genomes in Mandarivirus-infecting different citrus species. 3 Biotech 2019; 9:348. [PMID: 31497466 DOI: 10.1007/s13205-019-1876-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 08/18/2019] [Indexed: 02/06/2023] Open
Abstract
Citrus yellow vein-clearing virus (CYVCV) is a mandarivirus infecting citrus producing yellow vein-clearing symptoms. The leaf samples collected during surveys of different citrus-growing areas in India exhibited diverse symptoms and 40% of the plants were positive for CYVCV in RT-PCR, indicating the wide distribution of the virus in India. It was reported for first time that CYVCV infects kinnow mandarin and sweet oranges and produces chlorotic ringspots symptoms identical to Indian citrus ringspot virus (ICRSV). The complete genome sequences of CYVCV infecting four citrus cultivars have been deciphered through overlapping primers. All the four genomes comprise of 7531 nucleotides excluding the 3' poly (A) tail. The sequence identity of genomes of four CYVCV isolates in the present study ranged from 95.2 to 99.8% with genome sequences of 31 CYVCV isolates available in public domain and the mean genomic diversity was 0.017, indicating low level of heterogeneity. The phylogenetic analysis revealed that CYVCV isolates from India, Pakistan, and Turkey were clustered in the same clad apart from China isolates. The least normalized dN/dS mean value (0.092) indicated that RdRP region evolved under relatively stronger selection constraints than the other five coding regions of CYVCV. The four intragenic putative recombination events detected in RDP4 program occurred naturally in CYVCV genome, indicating the evolutionary progress of the virus. Tajima's and Fu and Li's D parameters were performed using genomic sequences in DnaSP v5 program and the retrieved negative values indicated the presence of limited genetic variability in CYVCV genomes. To the best of our knowledge, this is the first comprehensive report on molecular characterization of CYVCV from India. It will be helpful in understanding the evolutionary relationship of CYVCV and ICRSV.
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Affiliation(s)
- Ram Prasnna Meena
- 1Advanced Centre for Plant Virology Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
- 3Present Address: ICAR-Directorate of Medicinal and Aromatic Plants Research, Anand, Gujarat 387310 India
| | - K Prabha
- ICAR-Directorate of Floricultural Research, Pune, 411005 India
| | - V K Baranwal
- 1Advanced Centre for Plant Virology Division of Plant Pathology, ICAR-Indian Agricultural Research Institute, New Delhi, 110012 India
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27
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Zhou X, Lin W, Sun K, Wang S, Zhou X, Jackson AO, Li Z. Specificity of Plant Rhabdovirus Cell-to-Cell Movement. J Virol 2019; 93:e00296-19. [PMID: 31118256 PMCID: PMC6639277 DOI: 10.1128/jvi.00296-19] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/15/2019] [Indexed: 12/13/2022] Open
Abstract
Positive-stranded RNA virus movement proteins (MPs) generally lack sequence-specific nucleic acid-binding activities and display cross-family movement complementarity with related and unrelated viruses. Negative-stranded RNA plant rhabdoviruses encode MPs with limited structural and functional relatedness with other plant virus counterparts, but the precise mechanisms of intercellular transport are obscure. In this study, we first analyzed the abilities of MPs encoded by five distinct rhabdoviruses to support cell-to-cell movement of two positive-stranded RNA viruses by using trans-complementation assays. Each of the five rhabdovirus MPs complemented the movement of MP-defective mutants of tomato mosaic virus and potato X virus. In contrast, movement of recombinant MP deletion mutants of sonchus yellow net nucleorhabdovirus (SYNV) and tomato yellow mottle-associated cytorhabdovirus (TYMaV) was rescued only by their corresponding MPs, i.e., SYNV sc4 and TYMaV P3. Subcellular fractionation analyses revealed that SYNV sc4 and TYMaV P3 were peripherally associated with cell membranes. A split-ubiquitin membrane yeast two-hybrid assay demonstrated specific interactions of the membrane-associated rhabdovirus MPs only with their cognate nucleoproteins (N) and phosphoproteins (P). More importantly, SYNV sc4-N and sc4-P interactions directed a proportion of the N-P complexes from nuclear sites of replication to punctate loci at the cell periphery that partially colocalized with the plasmodesmata. Our data show that cell-to-cell movement of plant rhabdoviruses is highly specific and suggest that cognate MP-nucleocapsid core protein interactions are required for intra- and intercellular trafficking.IMPORTANCE Local transport of plant rhabdoviruses likely involves the passage of viral nucleocapsids through MP-gated plasmodesmata, but the molecular mechanisms are not fully understood. We have conducted complementation assays with MPs encoded by five distinct rhabdoviruses to assess their movement specificity. Each of the rhabdovirus MPs complemented the movement of MP-defective mutants of two positive-stranded RNA viruses that have different movement strategies. In marked contrast, cell-to-cell movement of two recombinant plant rhabdoviruses was highly specific in requiring their cognate MPs. We have shown that these rhabdovirus MPs are localized to the cell periphery and associate with cellular membranes, and that they interact only with their cognate nucleocapsid core proteins. These interactions are able to redirect viral nucleocapsid core proteins from their sites of replication to the cell periphery. Our study provides a model for the specific inter- and intracellular trafficking of plant rhabdoviruses that may be applicable to other negative-stranded RNA viruses.
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Affiliation(s)
- Xin Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Wenye Lin
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Kai Sun
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Shuo Wang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Andrew O Jackson
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, California, USA
| | - Zhenghe Li
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- Ministry of Agriculture Key Laboratory of Molecular Biology of Crop Pathogens and Insect Pests, Zhejiang University, Hangzhou, China
- Key Laboratory of Biology of Crop Pathogens and Insects of Zhejiang Province, Zhejiang University, Hangzhou, China
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28
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Ur Rehman A, Li Z, Yang Z, Waqas M, Wang G, Xu W, Li F, Hong N. The Coat Protein of Citrus Yellow Vein Clearing Virus Interacts with Viral Movement Proteins and Serves as an RNA Silencing Suppressor. Viruses 2019; 11:E329. [PMID: 30959816 PMCID: PMC6520955 DOI: 10.3390/v11040329] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/27/2019] [Accepted: 04/04/2019] [Indexed: 01/29/2023] Open
Abstract
Citrus yellow vein clearing virus is a newly accepted member of the genus Mandarivirus in the family Alphaflexiviridae. The triple gene block proteins (TGBp1, TGBp2 and TGBp3) encoded by plant viruses in this family function on facilitating virus movement. However, the protein function of citrus yellow vein clearing virus (CYVCV) have never been explored. Here, we showed in both yeast two-hybrid (Y2H) and bimolecular fluorescence (BiFC) assays that the coat protein (CP), TGBp1 and TGBp2 of CYVCV are self-interacting. Its CP also interacts with all three TGB proteins, and TGBp1 and TGBp2 interact with each other but not with TGBp3. Furthermore, the viral CP colocalizes with TGBp1 and TGBp3 at the plasmodesmata (PD) of epidermal cells of Nicotiana benthamiana leaves, and TGBp1 can translocate TGBp2 from granular-like structures embedded within ER networks to the PD. The results suggest that these proteins could coexist at the PD of epidermal cells of N. benthamiana. Using Agrobacterium infiltration-mediated RNA silencing assays, we show that CYVCV CP is a strong RNA silencing suppressor (RSS) triggered by positive-sense green fluorescent protein (GFP) RNA. The presented results provide insights for further revealing the mechanism of the viral movement and suppression of RNA silencing.
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Affiliation(s)
- Atta Ur Rehman
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Horticultural Crop (Fruit Trees) Biology and Germplasm Creation of the Ministry of Agriculture, Wuhan 430070, China.
- Plant Pathology Section, Central Cotton Research Institute, Sakrand, Sindh 67210, Pakistan.
| | - Zhuoran Li
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
| | - Zuokun Yang
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Horticultural Crop (Fruit Trees) Biology and Germplasm Creation of the Ministry of Agriculture, Wuhan 430070, China.
| | - Muhammad Waqas
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Guoping Wang
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Horticultural Crop (Fruit Trees) Biology and Germplasm Creation of the Ministry of Agriculture, Wuhan 430070, China.
| | - Wenxing Xu
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Horticultural Crop (Fruit Trees) Biology and Germplasm Creation of the Ministry of Agriculture, Wuhan 430070, China.
| | - Feng Li
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
| | - Ni Hong
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Horticultural Crop (Fruit Trees) Biology and Germplasm Creation of the Ministry of Agriculture, Wuhan 430070, China.
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Röder J, Dickmeis C, Commandeur U. Small, Smaller, Nano: New Applications for Potato Virus X in Nanotechnology. FRONTIERS IN PLANT SCIENCE 2019; 10:158. [PMID: 30838013 PMCID: PMC6390637 DOI: 10.3389/fpls.2019.00158] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 01/29/2019] [Indexed: 05/08/2023]
Abstract
Nanotechnology is an expanding interdisciplinary field concerning the development and application of nanostructured materials derived from inorganic compounds or organic polymers and peptides. Among these latter materials, proteinaceous plant virus nanoparticles have emerged as a key platform for the introduction of tailored functionalities by genetic engineering and conjugation chemistry. Tobacco mosaic virus and Cowpea mosaic virus have already been developed for bioimaging, vaccination and electronics applications, but the flexible and filamentous Potato virus X (PVX) has received comparatively little attention. The filamentous structure of PVX particles allows them to carry large payloads, which are advantageous for applications such as biomedical imaging in which multi-functional scaffolds with a high aspect ratio are required. In this context, PVX achieves superior tumor homing and retention properties compared to spherical nanoparticles. Because PVX is a protein-based nanoparticle, its unique functional properties are combined with enhanced biocompatibility, making it much more suitable for biomedical applications than synthetic nanomaterials. Moreover, PVX nanoparticles have very low toxicity in vivo, and superior pharmacokinetic profiles. This review focuses on the production of PVX nanoparticles engineered using chemical and/or biological techniques, and describes current and future opportunities and challenges for the application of PVX nanoparticles in medicine, diagnostics, materials science, and biocatalysis.
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Affiliation(s)
| | | | - Ulrich Commandeur
- Institute for Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
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30
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Chen I, Chen H, Huang Y, Huang H, Shenkwen L, Hsu Y, Tsai C. A thioredoxin NbTRXh2 from Nicotiana benthamiana negatively regulates the movement of Bamboo mosaic virus. MOLECULAR PLANT PATHOLOGY 2018; 19:405-417. [PMID: 28052479 PMCID: PMC6637981 DOI: 10.1111/mpp.12532] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 12/25/2016] [Accepted: 12/29/2016] [Indexed: 05/05/2023]
Abstract
An up-regulated gene derived from Bamboo mosaic virus (BaMV)-infected Nicotiana benthamiana plants was cloned and characterized in this study. BaMV is a single-stranded, positive-sense RNA virus. This gene product, designated as NbTRXh2, was matched with sequences of thioredoxin h proteins, a group of small proteins with a conserved active-site motif WCXPC conferring disulfide reductase activity. To examine how NbTRXh2 is involved in the infection cycle of BaMV, we used the virus-induced gene silencing technique to knock down NbTRXh2 expression in N. benthamiana and inoculated the plants with BaMV. We observed that, compared with control plants, BaMV coat protein accumulation increased in knockdown plants at 5 days post-inoculation (dpi). Furthermore, BaMV coat protein accumulation did not differ significantly between NbTRXh2-knockdown and control protoplasts at 24 hpi. The BaMV infection foci in NbTRXh2-knockdown plants were larger than those in control plants. In addition, BaMV coat protein accumulation decreased when NbTRXh2 was transiently expressed in plants. These results suggest that NbTRXh2 plays a role in restricting BaMV accumulation. Moreover, confocal microscopy results showed that NbTRXh2-OFP (NbTRXh2 fused with orange fluorescent protein) localized at the plasma membrane, similar to AtTRXh9, a homologue in Arabidopsis. The expression of the mutant that did not target the substrates failed to reduce BaMV accumulation. Co-immunoprecipitation experiments revealed that the viral movement protein TGBp2 could be the target of NbTRXh2. Overall, the functional role of NbTRXh2 in reducing the disulfide bonds of targeting factors, encoded either by the host or virus (TGBp2), is crucial in restricting BaMV movement.
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Affiliation(s)
- I‐Hsuan Chen
- Graduate Institute of BiotechnologyNational Chung Hsing UniversityTaichung402Taiwan
| | - Hui‐Ting Chen
- Graduate Institute of BiotechnologyNational Chung Hsing UniversityTaichung402Taiwan
| | - Ying‐Ping Huang
- Graduate Institute of BiotechnologyNational Chung Hsing UniversityTaichung402Taiwan
| | - Hui‐Chen Huang
- Biotechnology CenterNational Chung Hsing UniversityTaichung402Taiwan
| | - Lin‐Ling Shenkwen
- Graduate Institute of BiotechnologyNational Chung Hsing UniversityTaichung402Taiwan
| | - Yau‐Heiu Hsu
- Graduate Institute of BiotechnologyNational Chung Hsing UniversityTaichung402Taiwan
| | - Ching‐Hsiu Tsai
- Graduate Institute of BiotechnologyNational Chung Hsing UniversityTaichung402Taiwan
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31
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Esfandiari N, Arzanani MK, Koohi-Habibi M. The study of toxicity and pathogenicity risk of Potato Virus X/Herceptin nanoparticles as agents for cancer therapy. Cancer Nanotechnol 2018. [DOI: 10.1186/s12645-018-0036-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
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32
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Malpica-López N, Rajeswaran R, Beknazariants D, Seguin J, Golyaev V, Farinelli L, Pooggin MM. Revisiting the Roles of Tobamovirus Replicase Complex Proteins in Viral Replication and Silencing Suppression. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018; 31:125-144. [PMID: 29140168 DOI: 10.1094/mpmi-07-17-0164-r] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Tobamoviral replicase possesses an RNA-dependent RNA polymerase (RDR) domain and is translated from genomic (g)RNA via a stop codon readthrough mechanism at a one-to-ten ratio relative to a shorter protein lacking the RDR domain. The two proteins share methyltransferase and helicase domains and form a heterodimer implicated in gRNA replication. The shorter protein is also implicated in suppressing RNA silencing-based antiviral defenses. Using a stop codon mutant of Oilseed rape mosaic tobamovirus (ORMV), we demonstrate that the readthrough replicase (p182) is sufficient for gRNA replication and for subgenomic RNA transcription during systemic infection in Nicotiana benthamiana and Arabidopsis thaliana. However, the mutant virus displays milder symptoms and does not interfere with HEN1-mediated methylation of viral short interfering (si)RNAs or plant small (s)RNAs. The mutant virus tends to revert the stop codon, thereby restoring expression of the shorter protein (p125), even in the absence of plant Dicer-like activities that generate viral siRNAs. Plant RDR activities that generate endogenous siRNA precursors do not prevent replication or movement of the mutant virus, and double-stranded precursors of viral siRNAs representing the entire virus genome are likely synthesized by p182. Transgenic expression of p125 partially recapitulates the ORMV disease symptoms associated with overaccumulation of plant sRNAs. Taken together, the readthrough replicase p182 is sufficient for viral replication and transcription but not for silencing suppression. By contrast, the shorter p125 protein suppresses silencing, provokes severe disease symptoms, causes overaccumulation of unmethylated viral and plant sRNAs but it is not an essential component of the viral replicase complex.
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Affiliation(s)
| | | | - Daria Beknazariants
- 1 University of Basel, Department of Environmental Sciences, Basel, Switzerland
| | - Jonathan Seguin
- 1 University of Basel, Department of Environmental Sciences, Basel, Switzerland
| | - Victor Golyaev
- 1 University of Basel, Department of Environmental Sciences, Basel, Switzerland
| | | | - Mikhail M Pooggin
- 1 University of Basel, Department of Environmental Sciences, Basel, Switzerland
- 3 INRA, UMR BGPI, Montpellier, France
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Fujita N, Komatsu K, Ayukawa Y, Matsuo Y, Hashimoto M, Netsu O, Teraoka T, Yamaji Y, Namba S, Arie T. N-terminal region of cysteine-rich protein (CRP) in carlaviruses is involved in the determination of symptom types. MOLECULAR PLANT PATHOLOGY 2018; 19:180-190. [PMID: 27868376 PMCID: PMC6638135 DOI: 10.1111/mpp.12513] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 10/19/2016] [Accepted: 11/14/2016] [Indexed: 05/04/2023]
Abstract
Plant viruses in the genus Carlavirus include more than 65 members. Plants infected with carlaviruses exhibit various symptoms, including leaf malformation and plant stunting. Cysteine-rich protein (CRP) encoded by carlaviruses has been reported to be a pathogenicity determinant. Carlavirus CRPs contain two motifs in their central part: a nuclear localization signal (NLS) and a zinc finger motif (ZF). In addition to these two conserved motifs, carlavirus CRPs possess highly divergent, N-terminal, 34 amino acid residues with unknown function. In this study, to analyse the role of these distinct domains, we tested six carlavirus CRPs for their RNA silencing suppressor activity, ability to enhance the pathogenicity of a heterologous virus and effects on virus accumulation levels. Although all six tested carlavirus CRPs showed RNA silencing suppressor activity at similar levels, symptoms induced by the Potato virus X (PVX) heterogeneous system exhibited two different patterns: leaf malformation and whole-plant stunting. The expression of each carlavirus CRP enhanced PVX accumulation levels, which were not correlated with symptom patterns. PVX-expressing CRP with mutations in either NLS or ZF did not induce symptoms, suggesting that both motifs play critical roles in symptom expression. Further analysis using chimeric CRPs, in which the N-terminal region was replaced with the corresponding region of another CRP, suggested that the N-terminal region of carlavirus CRPs determined the exhibited symptom types. The up-regulation of a plant gene upp-L, which has been reported in a previous study, was also observed in this study; however, the expression level was not responsible for symptom types.
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Affiliation(s)
- Naoko Fujita
- Laboratory of Plant Pathology, Graduate School of AgricultureTokyo University of Agriculture and Technology (TUAT)183‐8509 FuchuJapan
- Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life SciencesThe University of Tokyo113‐8657 TokyoJapan
| | - Ken Komatsu
- Laboratory of Plant Pathology, Graduate School of AgricultureTokyo University of Agriculture and Technology (TUAT)183‐8509 FuchuJapan
| | - Yu Ayukawa
- Laboratory of Plant Pathology, Graduate School of AgricultureTokyo University of Agriculture and Technology (TUAT)183‐8509 FuchuJapan
- United Graduate School of Agricultural ScienceTokyo University of Agriculture and TechnologyFuchu183‐8509Japan
| | - Yuki Matsuo
- Laboratory of Plant Pathology, Graduate School of AgricultureTokyo University of Agriculture and Technology (TUAT)183‐8509 FuchuJapan
| | - Masayoshi Hashimoto
- Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life SciencesThe University of Tokyo113‐8657 TokyoJapan
| | - Osamu Netsu
- Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life SciencesThe University of Tokyo113‐8657 TokyoJapan
| | - Tohru Teraoka
- Laboratory of Plant Pathology, Graduate School of AgricultureTokyo University of Agriculture and Technology (TUAT)183‐8509 FuchuJapan
| | - Yasuyuki Yamaji
- Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life SciencesThe University of Tokyo113‐8657 TokyoJapan
| | - Shigetou Namba
- Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life SciencesThe University of Tokyo113‐8657 TokyoJapan
| | - Tsutomu Arie
- Laboratory of Plant Pathology, Graduate School of AgricultureTokyo University of Agriculture and Technology (TUAT)183‐8509 FuchuJapan
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Landeo-Ríos Y, Navas-Castillo J, Moriones E, Cañizares MC. The Heterologous Expression of the p22 RNA Silencing Suppressor of the Crinivirus Tomato Chlorosis Virus from Tobacco Rattle Virus and Potato Virus X Enhances Disease Severity but Does Not Complement Suppressor-Defective Mutant Viruses. Viruses 2017; 9:E358. [PMID: 29186781 PMCID: PMC5744133 DOI: 10.3390/v9120358] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 11/09/2017] [Accepted: 11/22/2017] [Indexed: 11/17/2022] Open
Abstract
To counteract host antiviral RNA silencing, plant viruses express suppressor proteins that function as pathogenicity enhancers. The genome of the Tomato chlorosis virus (ToCV) (genus Crinivirus, family Closteroviridae) encodes an RNA silencing suppressor, the protein p22, that has been described as having one of the longest lasting local suppressor activities when assayed in Nicotiana benthamiana. Since suppression of RNA silencing and the ability to enhance disease severity are closely associated, we analyzed the effect of expressing p22 in heterologous viral contexts. Thus, we studied the effect of the expression of ToCV p22 from viral vectors Tobacco rattle virus (TRV) and Potato virus X (PVX), and from attenuated suppressor mutants in N. benthamiana plants. Our results show that although an exacerbation of disease symptoms leading to plant death was observed in the heterologous expression of ToCV p22 from both viruses, only in the case of TRV did increased viral accumulation occur. The heterologous expression of ToCV p22 could not complement suppressor-defective mutant viruses.
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Affiliation(s)
| | | | | | - M. Carmen Cañizares
- Instituto de Hortofruticultura Subtropical y Mediterránea “La Mayora”—Universidad de Málaga—Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental “La Mayora”, Algarrobo-Costa, 29750 Málaga, Spain; (Y.L.-R.); (J.N.-C.); (E.M.)
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Hong JS, Ju HJ. The Plant Cellular Systems for Plant Virus Movement. THE PLANT PATHOLOGY JOURNAL 2017; 33:213-228. [PMID: 28592941 PMCID: PMC5461041 DOI: 10.5423/ppj.rw.09.2016.0198] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2016] [Revised: 11/05/2016] [Accepted: 11/13/2016] [Indexed: 05/24/2023]
Abstract
Plasmodesmata (PDs) are specialized intercellular channels that facilitate the exchange of various molecules, including sugars, ribonucleoprotein complexes, transcription factors, and mRNA. Their diameters, estimated to be 2.5 nm in the neck region, are too small to transfer viruses or viral genomes. Tobacco mosaic virus and Potexviruses are the most extensively studied viruses. In viruses, the movement protein (MP) is responsible for the PD gating that allows the intercellular movement of viral genomes. Various host factors interact with MP to regulate complicated mechanisms related to PD gating. Virus replication and assembly occur in viral replication complex (VRC) with membrane association, especially in the endoplasmic reticulum. VRC have a highly organized structure and are highly regulated by interactions among the various host factors, proteins encoded by the viral genome, and the viral genome. Virus trafficking requires host machineries, such as the cytoskeleton and the secretory systems. MP facilitates the virus replication and movement process. Despite the current level of understanding of virus movement, there are still many unknown and complex interactions between virus replication and virus movement. While numerous studies have been conducted to understand plant viruses with regards to cell-to-cell movement and replication, there are still many knowledge gaps. To study these interactions, adequate research tools must be used such as molecular, and biochemical techniques. Without such tools, virologists will not be able to gain an accurate or detailed understanding of the virus infection process.
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Affiliation(s)
- Jin-Sung Hong
- Department of Applied Biology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 24341, Korea
| | - Ho-Jong Ju
- Department of Agricultural Biology, College of Agricultural Life Science, Chonbuk National University, Jeonju 54896, Korea
- Plant Medicinal Research Center, College of Agricultural Life Science, Chonbuk National University, Jeonju 54896, Korea
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Borniego MB, Karlin D, Peña EJ, Robles Luna G, García ML. Bioinformatic and mutational analysis of ophiovirus movement proteins, belonging to the 30K superfamily. Virology 2016; 498:172-180. [PMID: 27596536 DOI: 10.1016/j.virol.2016.08.027] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 08/19/2016] [Accepted: 08/27/2016] [Indexed: 01/21/2023]
Abstract
Ophioviridae is a family of segmented, negative-sense, single-stranded RNA plant viruses. We showed that their cell-to-cell movement protein (MP) is an isolated member of the 30K MP superfamily with a unique structural organization. All 30K MPs share a core domain that contains a nearly-invariant signature aspartate. We examined its role in the MP of Citrus psorosis virus (CPsV) and Mirafiori lettuce big-vein virus (MiLBVV). Alanine substitution of this aspartate prevented plasmodesmata accumulation of MP(MiLBVV), while MP(CPsV) was not affected. The capacity of ophiovirus MPs to increase the plasmodesmata size exclusion limit and non-cell autonomous protein feature was abolished in both mutants. To investigate the role of the signature aspartate in cell-to-cell movement, we constructed a new movement-deficient Tobacco mosaic virus vector used for trans-complementation assays. We showed that both ophiovirus MP mutants lack the cell-to-cell movement capacity, confirming that this signature aspartate is essential for viral cell-to-cell movement.
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Affiliation(s)
- María Belén Borniego
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata CONICET, Fac. Cs. Exactas, U.N.L.P., Calles 49 y 115, La Plata, Argentina
| | - David Karlin
- Department of Zoology, University of Oxford, Oxford OX1 3PS, UK; The Division of Structural Biology, Henry Wellcome Building, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Eduardo José Peña
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata CONICET, Fac. Cs. Exactas, U.N.L.P., Calles 49 y 115, La Plata, Argentina
| | - Gabriel Robles Luna
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata CONICET, Fac. Cs. Exactas, U.N.L.P., Calles 49 y 115, La Plata, Argentina
| | - María Laura García
- Instituto de Biotecnología y Biología Molecular, CCT-La Plata CONICET, Fac. Cs. Exactas, U.N.L.P., Calles 49 y 115, La Plata, Argentina.
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García Ruíz D, Olarte Quintero MA, Gutiérrez Sánchez PA, Marín Montoya MA. Detección serológica y molecular del Potato virus X (PVX) en tubérculos-semilla de papa (Solanum tuberosum L. y Solanum phureja Juz. Bukasov) en Antioquia, Colombia. REVISTA COLOMBIANA DE BIOTECNOLOGÍA 2016. [DOI: 10.15446/rev.colomb.biote.v18n1.51389] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
<p>El Potato virus (PVX) es uno de los virus más limitantes del cultivo de la papa en el mundo. Es transmitido solamente por contacto y por tubérculo-semilla. Su control se fundamenta en la siembra de tubérculos certificados por su sanidad viral y en la disponibilidad de metodologías de diagnóstico altamente sensibles. En este trabajo se evaluó la prevalencia del PVX en cuatro diferentes tejidos de tubérculos de Solanum tuberosum subsp. andigena var. Diacol-Capiro y S. phureja var. Criolla Colombia utilizando pruebas de DAS-ELISA para 128 submuestras y de RT-qPCR para 32 grupos de submuestras (4 submuestras/grupo). Los resultados de las pruebas serológicas indicaron la presencia de PVX en el 6,25 y 50% de las submuestras analizadas para la variedad Diacol-Capiro y Criolla Colombia, respectivamente; mientras que los niveles de prevalencia del PVX utilizando la detección por RT-qPCR fueron del 93,75%, independientemente de la variedad de papa y del tejido evaluado. Los valores promedio del ciclo umbral (Ct) en las RT-qPCR fueron de 25,6 (Ct=18,02 a 34,49) y el análisis de las curvas de desnaturalización permitió identificar dos variantes del virus con valores de Tm de 79,5±1°C y 83,7±1°C. La secuenciación de los amplicones obtenidos por RT-qPCR para los controles positivos y para dos de las muestras, confirmó su naturaleza viral. Estos resultados señalan unos muy altos niveles de prevalencia de PVX en el material de siembra de papa en Antioquia y la necesidad de fortalecer los programas de certificación de semilla con pruebas de detección como RT-qPCR.</p>
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Lico C, Benvenuto E, Baschieri S. The Two-Faced Potato Virus X: From Plant Pathogen to Smart Nanoparticle. FRONTIERS IN PLANT SCIENCE 2015; 6:1009. [PMID: 26635836 PMCID: PMC4646960 DOI: 10.3389/fpls.2015.01009] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 10/30/2015] [Indexed: 05/24/2023]
Abstract
Potato virus X (PVX) is a single-stranded RNA plant virus, historically investigated in light of the detrimental effects on potato, the world's fourth most important food commodity. The study of the interactions with cells, and more generally with the plant, both locally and systemically, significantly contributed to unveil the mechanisms underlying gene silencing, fundamental not only in plant virology but also in the study of gene expression regulation. Unraveling the molecular events of PVX infection paved the way for the development of different viral expression vectors and consequential applications in functional genomics and in the biosynthesis of heterologous proteins in plants. Apart from that, the ease of manipulation and the knowledge of the virus structure (particle dimensions, shape and physicochemical features) are inspiring novel applications, mainly focused on nanobiotechnology. This review will lead the reader in this area, spanning from fundamental to applied research, embracing fields from plant pathology to vaccine and drug-targeted delivery, imaging and material sciences. Due to the versatile moods, PVX holds promise to become an interesting nanomaterial, in view to create the widest possible arsenal of new "bio-inspired" devices to face evolving issues in biomedicine and beyond.
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Affiliation(s)
- Chiara Lico
- Laboratory of Biotechnology , ENEA, Rome, Italy
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39
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Landeo-Ríos YM, Navas-Castillo J, Moriones E, Cañizares MC. Genetic diversity and silencing suppression activity of the p22 protein of Tomato chlorosis virus isolates from tomato and sweet pepper. Virus Genes 2015; 51:283-9. [PMID: 26334965 DOI: 10.1007/s11262-015-1244-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 08/26/2015] [Indexed: 10/23/2022]
Abstract
As for other bipartite criniviruses (genus Crinivirus, family Closteroviridae), the genome of Tomato chlorosis virus encodes an RNA silencing suppressor, the protein p22, in the 3'-proximal region of RNA1. This protein has been reported as having one of the longest lasting local suppressor activities when transiently expressed in Nicotiana benthamiana. Here, we examined the genetic diversity of the p22 gene in ToCV isolates from tomato and sweet pepper. The p22 gene sequences clearly grouped into two separated clades. However, functional analysis of both types of p22 proteins indicated no evident differences in suppressor activity. Our findings provide experimental evidence that the presence of a "strong" silencing suppressor is a conserved feature of ToCV isolates.
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Affiliation(s)
- Yazmín M Landeo-Ríos
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"- Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental "La Mayora", Algarrobo-Costa, 29750, Málaga, Spain
| | - Jesús Navas-Castillo
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"- Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental "La Mayora", Algarrobo-Costa, 29750, Málaga, Spain
| | - Enrique Moriones
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"- Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental "La Mayora", Algarrobo-Costa, 29750, Málaga, Spain
| | - M Carmen Cañizares
- Instituto de Hortofruticultura Subtropical y Mediterránea "La Mayora"- Universidad de Málaga - Consejo Superior de Investigaciones Científicas (IHSM-UMA-CSIC), Estación Experimental "La Mayora", Algarrobo-Costa, 29750, Málaga, Spain.
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Putlyaev EV, Smirnov AA, Karpova OV, Atabekov JG. Double Subgenomic Promoter Control for a Target Gene Superexpression by a Plant Viral Vector. BIOCHEMISTRY. BIOKHIMIIA 2015; 80:1039-46. [PMID: 26547072 DOI: 10.1134/s000629791508009x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Several new deconstructed vectors based on a potexvirus genome sequence for efficient expression of heterologous proteins in plants were designed. The first obtained vector (AltMV-single), based on the Alternanthera mosaic virus (AltMV) strain MU genome, bears a typical architecture for deconstructed plant viral vectors, i.e. a triple gene block was deleted from the viral genome and the model gene of interest was placed under control of the first viral subgenomic promoter. To enhance the efficiency of expression, maintained by the AltMV-single, another vector (AltMV-double) was designed. In AltMV-double, the gene of interest was controlled by two viral subgenomic promoters located sequentially without a gap upstream of the target gene. It was found that AltMV-double provided a significantly higher level of accumulation of the target protein in plants than AltMV-single. Moreover, our data clearly show the requirement of the presence and functioning of both the subgenomic promoters for demonstrated high level of target protein expression by AltMV-double. Taken together, our results describe an additional possible way to enhance the efficiency of transient protein expression maintained in plants by a plant viral vector.
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Affiliation(s)
- E V Putlyaev
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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41
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Liou MR, Hu CC, Chou YL, Chang BY, Lin NS, Hsu YH. Viral elements and host cellular proteins in intercellular movement of Bamboo mosaic virus. Curr Opin Virol 2015; 12:99-108. [PMID: 25951346 DOI: 10.1016/j.coviro.2015.04.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 04/15/2015] [Accepted: 04/17/2015] [Indexed: 12/23/2022]
Abstract
As a member of the genus Potexvirus, Bamboo mosaic virus (BaMV) also belongs to the plant viruses that encode triple gene block proteins (TGBps) for intercellular movement within the host plants. Recent studies of the movement mechanisms of BaMV have revealed similarities and differences between BaMV and other potexviruses. This review focuses on the general aspects of viral and host elements involved in BaMV movement, the interactions among these elements, and the possible pathways for intra- and intercellular trafficking of BaMV. Major features of BaMV trafficking that have not been demonstrated in other potexviruses include: (i) the involvement of replicase, (ii) fine regulation by coat protein phosphorylation, (iii) the key roles played by TGBp3, (iv) the use of virions as the major transported form, and (v) the involvement of specific host factors, such as Ser/Thr kinase-like protein of Nicotiana benthamiana. We also highlight areas for future study that will provide a more comprehensive understanding of the detailed interactions among viral movement proteins and host factors, as well as the regulatory mechanisms of virus movement. Finally, a model based on the current knowledge is proposed to depict the diverse abilities of BaMV to utilize a wide range of mechanisms for efficient intercellular movement.
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Affiliation(s)
- Ming-Ru Liou
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Chung-Chi Hu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Yuan-Lin Chou
- Institute of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan
| | - Ban-Yang Chang
- Institute of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan
| | - Na-Sheng Lin
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan; Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan.
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Morozov SY, Solovyev AG. Phylogenetic relationship of some "accessory" helicases of plant positive-stranded RNA viruses: toward understanding the evolution of triple gene block. Front Microbiol 2015; 6:508. [PMID: 26042118 PMCID: PMC4436898 DOI: 10.3389/fmicb.2015.00508] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 05/08/2015] [Indexed: 12/16/2022] Open
Abstract
Recently, we hypothesized that silencing suppression activity gained by a viral replicative helicase led to the emergence of the second helicase possessing activity of the viral silencing suppressor and/or movement protein (MP). Our hypothesis accounted for the evolutionary origin of the specialized ‘triple gene block’ (TGB) in plant virus genomes encoding the MPs TGB1, TGB2, and TGB3 required for viral cell-to-cell transport through plasmodesmata. Here, we used public transcriptome databases to identify previously unrecognized viruses. The analysis of novel viral genomes further supported the previously proposed scenario of TGB origin and evolution, which included the following steps. First, the accessory helicase gene could have been acquired by horizontal gene transfer (HGT) presumably occured independently in different virus groups. Second, the TGB2 gene evolved by HGT or autonomization of the C-terminal transmembrane domain found in at least one TGB1 helicase. Third, the TGB3 gene has most likely emerged in the genomic block consisting of the TGB1 and TGB2 genes.
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Affiliation(s)
- Sergey Y Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University Moscow, Russia
| | - Andrey G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University Moscow, Russia
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Andika IB, Maruyama K, Sun L, Kondo H, Tamada T, Suzuki N. Differential contributions of plant Dicer-like proteins to antiviral defences against potato virus X in leaves and roots. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 81:781-93. [PMID: 25619543 DOI: 10.1111/tpj.12770] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 01/14/2015] [Accepted: 01/15/2015] [Indexed: 06/04/2023]
Abstract
Members of the plant Dicer-like (DCL) protein family are the critical components of the RNA-silencing pathway that mediates innate antiviral defence. The distinct antiviral role of each individual DCL protein has been established with mostly based on observations of aerial parts of plants. Thus, although the roots are closely associated with the life cycle of many plant viruses, little is known about the antiviral activities of DCL proteins in roots. We observed that antiviral silencing strongly inhibits potato virus X (PVX) replication in roots of some susceptible Solanaceae species. Silencing of the DCL4 homolog in Nicotiana benthamiana partially elevated PVX replication levels in roots. In Arabidopsis thaliana, which was originally considered a non-host plant of PVX, high levels of PVX accumulation in inoculated leaves were achieved by inactivation of DCL4, while in the upper leaves and roots, it required the additional inactivation of DCL2. In transgenic A. thaliana carrying the PVX amplicon with a green fluorescent protein (GFP) gene insertion in the chromosome (AMP243 line), absence of DCL4 enabled high levels of PVX-GFP accumulation in various aerial organs but not in the roots, suggesting that DCL4 is critical for intracellular antiviral silencing in shoots but not in roots, where it can be functionally compensated by other DCL proteins. Together, the high level of functional redundancies among DCL proteins may contribute to the potent antiviral activities against PVX replication in roots.
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Affiliation(s)
- Ida Bagus Andika
- Institute of Plant Science and Resources (IPSR), Okayama University, 2-20-1, Chuo, Kurashiki, 710-0046, Japan
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Senanayake DMJB, Mandal B. Expression of symptoms, viral coat protein and silencing suppressor gene during mixed infection of a N-Wi strain of potato virus Y and an asymptomatic strain of potato virus X. Virusdisease 2015; 25:314-21. [PMID: 25674598 DOI: 10.1007/s13337-014-0204-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 02/07/2014] [Indexed: 11/26/2022] Open
Abstract
Potato virus Y (PVY) and potato virus X (PVX), the RNA viruses of two different genera results into synergistic interactions on mixed infection. In this study, a N-Wi strain of PVY and a PVX strain that is asymptomatic on potato were used to study their interactions during mixed infection in Nicotiana benthamiana and Nicotiana tabacum with reference to symptom expression, level of coat protein (CP) using ELISA and suppressor gene using real time PCR under high temperature (26-40 °C) and low temperature (5-25 °C) conditions. Both mixed and single infection caused severe necrosis and death of N. benthamiana plants. Single infection of these viruses in N. tabacum showed mild symptoms but mixed infection caused more severe symptoms. Synergistic symptoms were more pronounced under low temperature conditions than at high temperature. In low temperature conditions, the CP level of PVX in N. benthamiana was twofold higher than PVY and both the viruses reached at peak at 28 dpi in single virus infection. When PVY and PVX inoculated together, the CP levels of both the viruses increased and reached to the peak earlier (within 7-14 days) than that in the single virus inoculation. Although, the CP level of PVX was higher than PVY in mixed infection, at later stage (28 dpi) both the CP level declined to the similar level. The level of p25 suppressor gene was higher than HC-Pro in single inoculation. However, under mixed inoculation of PVY and PVX, expression of p25 was declined to the level of HC-Pro when the CP levels of both the virus also were observed to decline. The expression pattern of CP and suppressor gene was different in plants when mixed infection was created by inoculation of one virus followed by the other. This study showed the level of CP and suppressor gene of specific strain of PVY and PVX during their mixed infection in tobacco.
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Affiliation(s)
- D M J B Senanayake
- Advanced Centre for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, 110012 India
| | - B Mandal
- Advanced Centre for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, 110012 India
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Aguilar E, Almendral D, Allende L, Pacheco R, Chung BN, Canto T, Tenllado F. The P25 protein of potato virus X (PVX) is the main pathogenicity determinant responsible for systemic necrosis in PVX-associated synergisms. J Virol 2015; 89:2090-103. [PMID: 25473046 PMCID: PMC4338884 DOI: 10.1128/jvi.02896-14] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2014] [Accepted: 11/24/2014] [Indexed: 01/08/2023] Open
Abstract
UNLABELLED Most plant viruses counter the RNA silencing-based antiviral defense by expressing viral suppressors of RNA silencing (VSRs). In this sense, VSRs may be regarded as virulence effectors that can be recognized by the host as avirulence (avr) factors to induce R-mediated resistance. We made use of Agrobacterium-mediated transient coexpression of VSRs in combination with Potato virus X (PVX) to recapitulate in local tissues the systemic necrosis (SN) caused by PVX-potyvirus synergistic infections in Nicotiana benthamiana. The hypersensitive response (HR)-like response was associated with an enhanced accumulation of PVX subgenomic RNAs. We further show that expression of P25, the VSR of PVX, in the presence of VSR from different viruses elicited an HR-like response in Nicotiana spp. Furthermore, the expression of P25 by a Plum pox virus (PPV) vector was sufficient to induce an increase of PPV pathogenicity that led to necrotic mottling. A frameshift mutation in the P25 open reading frame (ORF) of PVX did not lead to necrosis when coexpressed with VSRs. These findings indicate that P25 is the main PVX determinant involved in eliciting a systemic HR-like response in PVX-associated synergisms. Moreover, we show that silencing of SGT1 and RAR1 attenuated cell death in both PVX-potyvirus synergistic infection and the HR-like response elicited by P25. Our study underscores that P25 variants that have impaired ability to suppress RNA silencing cannot act as elicitors when synergized by the presence of other VSRs. These findings highlight the importance of RNA silencing suppression activity in the HR-like response elicited by VSRs in certain hosts. IMPORTANCE The work presented here describes how the activity of the PVX suppressor P25 elicits an HR-like response in Nicotiana spp. when overexpressed with other VSR proteins. This finding suggests that the SN response caused by PVX-associated synergisms is a delayed immune response triggered by P25, once it reaches a threshold level by the action of other VSRs. Moreover, this work supports the contention that the silencing suppressor activity of PVX P25 protein is a prerequisite for HR elicitation. We propose that unidentified avr determinants could be involved in other cases of viral synergisms in which heterologous "helper" viruses encoding strong VSRs exacerbate the accumulation of the avr-encoding virus.
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Affiliation(s)
- Emmanuel Aguilar
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - David Almendral
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Lucía Allende
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Remedios Pacheco
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Bong Nam Chung
- National Institute of Horticultural & Herbal Science, Agricultural Research Center for Climate Change, Jeju Island, Republic of Korea
| | - Tomás Canto
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | - Francisco Tenllado
- Departamento de Biología Medioambiental, Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
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Mathioudakis MM, Rodríguez-Moreno L, Sempere RN, Aranda MA, Livieratos I. Multifaceted capsid proteins: multiple interactions suggest multiple roles for Pepino mosaic virus capsid protein. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:1356-69. [PMID: 25162316 DOI: 10.1094/mpmi-07-14-0195-r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Pepino mosaic virus (PepMV) (family Alphaflexiviridae, genus Potexvirus) is a mechanically transmitted tomato pathogen that, over the last decade, has evolved from emerging to endemic worldwide. Here, two heat-shock cognate (Hsc70) isoforms were identified as part of the coat protein (CP)/Hsc70 complex in vivo, following full-length PepMV and CP agroinoculation. PepMV accumulation was severely reduced in Hsp70 virus-induced gene silenced and in quercetin-treated Nicotiana benthamiana plants. Similarly, in vitro-transcribed as well as virion RNA input levels were reduced in quercetin-treated protoplasts, suggesting an essential role for Hsp70 in PepMV replication. As for Potato virus X, the PepMV CP and triple gene-block protein 1 (TGBp1) self-associate and interact with each other in vitro but, unlike in the prototype, both PepMV proteins represent suppressors of transgene-induced RNA silencing with different modes of action; CP is a more efficient suppressor of RNA silencing, sequesters the silencing signal by preventing its spread to neighboring cells and its systemic movement. Here, we provide evidence for additional roles of the PepMV CP and host-encoded Hsp70 in viral infection, the first as a truly multifunctional protein able to specifically bind to a host chaperone and to counterattack an RNA-based defense mechanism, and the latter as an essential factor for PepMV infection.
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47
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Li MJ, Kim JK, Seo EY, Hong SM, Hwang EI, Moon JK, Domier LL, Hammond J, Youn YN, Lim HS. Sequence variability in the HC-Pro coding regions of Korean soybean mosaic virus isolates is associated with differences in RNA silencing suppression. Arch Virol 2014; 159:1373-83. [PMID: 24378822 DOI: 10.1007/s00705-013-1964-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Accepted: 12/17/2013] [Indexed: 11/25/2022]
Abstract
Soybean mosaic virus (SMV), a member of the family Potyviridae, is an important viral pathogen affecting soybean production in Korea. Variations in helper component proteinase (HC-Pro) sequences and the pathogenicity of SMV samples from seven Korean provinces were compared with those of previously characterized SMV isolates from China, Korea and the United States. Phylogenetic analysis separated 16 new Korean SMV isolates into two groups. Fourteen of the new Korean SMV samples belonged to group II and were very similar to U.S. strain SMV G7 and Chinese isolate C14. One isolate in group II, A297-13, differed at three amino acid positions (L54F, N286D, D369N) in the HC-Pro coding sequence from severe isolates and SMV 413, showed very weak silencing suppressor activity, and produced only mild symptoms in soybean. To test the role of each amino acid substitution in RNA silencing and viral RNA accumulation, a series of point mutations was constructed. Substitution of N for D at position 286 in HC-Pro of SMV A297-12 significantly reduced silencing suppression activity. When the mutant HC-Pro of A297-13 was introduced into an infectious clone of SMV 413, accumulation of viral RNA was reduced to less than 3 % of the level of SMV 413 containing HC-Pro of A297-12 at 10 days post-inoculation (dpi) but increased to 40 % of SMV 413(HC-Pro A297-12) at 40 dpi. At 50 dpi RNA accumulation of SMV 413(HC-Pro A297-13) was similar to that of SMV 413(HC-Pro A297-12). However, at 50 dpi, the D at position 286 of HC-Pro in SMV 413(HC-Pro A297-13) was found to have reverted to N. The results showed that 1) a naturally occurring mutation in HC-Pro significantly reduced silencing suppression activity and accumulation of transgene and viral RNAs, and 2) that there was strong selection for revision to wild type when the mutation was introduced into an infectious clone of SMV.
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Affiliation(s)
- Mei-Jia Li
- Department of Applied Biology, Chungnam National University, Daejeon, 305-764, Korea
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Thekke-Veetil T, Ho T, Keller KE, Martin RR, Tzanetakis IE. A new ophiovirus is associated with blueberry mosaic disease. Virus Res 2014; 189:92-6. [PMID: 24874194 DOI: 10.1016/j.virusres.2014.05.019] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 05/16/2014] [Accepted: 05/17/2014] [Indexed: 11/16/2022]
Abstract
Blueberry mosaic disease (BMD) was first described more than 60 years ago and is caused by a yet unidentified graft transmissible agent. A combination of traditional methods and next generation sequencing disclosed the presence of a new ophiovirus in symptomatic plants. The virus was detected in all BMD samples collected from several production areas of North America and was thus named blueberry mosaic associated virus. Phylogenetic analysis, supported by high bootstrap values, places the virus within the family Ophioviridae. The genome organization resembles that of citrus psorosis virus, the type member of the genus Ophiovirus. The implications of this discovery in BMD control and blueberry virus certification schemes are also discussed.
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Affiliation(s)
- Thanuja Thekke-Veetil
- Department of Plant Pathology, Division of Agriculture, University of Arkansas System, Fayetteville, AR 72701, USA
| | - Thien Ho
- Department of Plant Pathology, Division of Agriculture, University of Arkansas System, Fayetteville, AR 72701, USA
| | | | | | - Ioannis E Tzanetakis
- Department of Plant Pathology, Division of Agriculture, University of Arkansas System, Fayetteville, AR 72701, USA.
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Perraki A, Binaghi M, Mecchia MA, Gronnier J, German-Retana S, Mongrand S, Bayer E, Zelada AM, Germain V. StRemorin1.3 hampers Potato virus X TGBp1 ability to increase plasmodesmata permeability, but does not interfere with its silencing suppressor activity. FEBS Lett 2014; 588:1699-705. [PMID: 24657438 DOI: 10.1016/j.febslet.2014.03.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 02/20/2014] [Accepted: 03/06/2014] [Indexed: 01/19/2023]
Abstract
The Triple Gene Block 1 (TGBp1) protein encoded by the Potato virus X is a multifunctional protein that acts as a suppressor of RNA silencing or facilitates the passage of virus from cell to cell by promoting the plasmodesmata opening. We previously showed that the membrane raft protein StRemorin1.3 is able to impair PVX infection. Here, we show that overexpressed StRemorin1.3 does not impair the silencing suppressor activity of TGBp1, but affects its ability to increase plasmodesmata permeability. A similar effect on plasmodesmata permeability was observed with other movement proteins, suggesting that REM is a general regulator of plasmodesmal size exclusion limit. These results add to our knowledge of the mechanisms underlying the StREM1.3 role in virus infection.
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Affiliation(s)
- Artemis Perraki
- CNRS, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, F-33000 Villenave d'Ornon, France; Univ. Bordeaux, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, F-33000 Villenave d'Ornon, France
| | - Maria Binaghi
- Laboratorio de Agrobiotecnología, DFBMC - Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IBBEA, CONICET-UBA, Buenos Aires, Argentina
| | - Martin A Mecchia
- Laboratorio de Agrobiotecnología, DFBMC - Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IBBEA, CONICET-UBA, Buenos Aires, Argentina
| | - Julien Gronnier
- CNRS, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, F-33000 Villenave d'Ornon, France; Univ. Bordeaux, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, F-33000 Villenave d'Ornon, France
| | - Sylvie German-Retana
- Equipe de Virologie, UMR BFP 1332 INRA, CS 20032, 33882 Villenave d'Ornon, France
| | - Sébastien Mongrand
- CNRS, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, F-33000 Villenave d'Ornon, France; Univ. Bordeaux, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, F-33000 Villenave d'Ornon, France.
| | - Emmanuelle Bayer
- CNRS, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, F-33000 Villenave d'Ornon, France; Univ. Bordeaux, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, F-33000 Villenave d'Ornon, France
| | - Alicia M Zelada
- Laboratorio de Agrobiotecnología, DFBMC - Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, IBBEA, CONICET-UBA, Buenos Aires, Argentina
| | - Véronique Germain
- CNRS, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, F-33000 Villenave d'Ornon, France; Univ. Bordeaux, Laboratoire de Biogenèse Membranaire (LBM), UMR 5200, F-33000 Villenave d'Ornon, France
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50
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Okano Y, Senshu H, Hashimoto M, Neriya Y, Netsu O, Minato N, Yoshida T, Maejima K, Oshima K, Komatsu K, Yamaji Y, Namba S. In Planta Recognition of a Double-Stranded RNA Synthesis Protein Complex by a Potexviral RNA Silencing Suppressor. THE PLANT CELL 2014; 26:2168-2183. [PMID: 24879427 PMCID: PMC4079376 DOI: 10.1105/tpc.113.120535] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Revised: 04/23/2014] [Accepted: 05/09/2014] [Indexed: 05/22/2023]
Abstract
RNA silencing plays an important antiviral role in plants and invertebrates. To counteract antiviral RNA silencing, most plant viruses have evolved viral suppressors of RNA silencing (VSRs). TRIPLE GENE BLOCK PROTEIN1 (TGBp1) of potexviruses is a well-characterized VSR, but the detailed mechanism by which it suppresses RNA silencing remains unclear. We demonstrate that transgenic expression of TGBp1 of plantago asiatica mosaic virus (PlAMV) induced developmental abnormalities in Arabidopsis thaliana similar to those observed in mutants of SUPPRESSOR OF GENE SILENCING3 (SGS3) and RNA-DEPENDENT RNA POLYMERASE6 (RDR6) required for the trans-acting small interfering RNA synthesis pathway. PlAMV-TGBp1 inhibits SGS3/RDR6-dependent double-stranded RNA synthesis in the trans-acting small interfering RNA pathway. TGBp1 interacts with SGS3 and RDR6 and coaggregates with SGS3/RDR6 bodies, which are normally dispersed in the cytoplasm. In addition, TGBp1 forms homooligomers, whose formation coincides with TGBp1 aggregation with SGS3/RDR6 bodies. These results reveal the detailed molecular function of TGBp1 as a VSR and shed new light on the SGS3/RDR6-dependent double-stranded RNA synthesis pathway as another general target of VSRs.
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Affiliation(s)
- Yukari Okano
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Hiroko Senshu
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Masayoshi Hashimoto
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yutaro Neriya
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Osamu Netsu
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Nami Minato
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Tetsuya Yoshida
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kensaku Maejima
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kenro Oshima
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Ken Komatsu
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Yasuyuki Yamaji
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Shigetou Namba
- Laboratory of Plant Pathology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
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