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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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Lazareva EA, Atabekova AK, Lezzhov AA, Morozov SY, Heinlein M, Solovyev AG. Virus Genome-Based Reporter for Analyzing Viral Movement Proteins and Plasmodesmata Permeability. Methods Mol Biol 2022; 2457:333-349. [PMID: 35349152 DOI: 10.1007/978-1-0716-2132-5_23] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Plant virus movement proteins (MPs) mediate cell-to-cell movement of the virus genome through plasmodesmata (PD). MPs target PD to increase their size exclusion limit (SEL), and this MP function is essential for virus intercellular trafficking. In this chapter, we describe the use of a Potato virus X genome-derived reporter for agroinfiltration-based identification of virus genome-encoded MPs and analysis of the ability of individual viral MPs or plant proteins to increase the PD SEL.
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Affiliation(s)
- Ekaterina A Lazareva
- Department of Virology, Biological Faculty, Moscow State University, Moscow, Russia
| | - Anastasia K Atabekova
- Department of Virology, Biological Faculty, Moscow State University, Moscow, Russia
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
| | - Alexander A Lezzhov
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
- Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow, Russia
| | - Sergey Y Morozov
- Department of Virology, Biological Faculty, Moscow State University, Moscow, Russia
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
| | - Manfred Heinlein
- Institut de Biologie Moléculaire des Plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Andrey G Solovyev
- Department of Virology, Biological Faculty, Moscow State University, Moscow, Russia.
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia.
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Akamatsu A, Fujiwara M, Hamada S, Wakabayashi M, Yao A, Wang Q, Kosami KI, Dang TT, Kaneko-Kawano T, Fukada F, Shimamoto K, Kawano Y. The Small GTPase OsRac1 Forms Two Distinct Immune Receptor Complexes Containing the PRR OsCERK1 and the NLR Pit. PLANT & CELL PHYSIOLOGY 2021; 62:1662-1675. [PMID: 34329461 DOI: 10.1093/pcp/pcab121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 07/28/2021] [Accepted: 07/30/2021] [Indexed: 06/13/2023]
Abstract
Plants employ two different types of immune receptors, cell surface pattern recognition receptors (PRRs) and intracellular nucleotide-binding and leucine-rich repeat-containing proteins (NLRs), to cope with pathogen invasion. Both immune receptors often share similar downstream components and responses but it remains unknown whether a PRR and an NLR assemble into the same protein complex or two distinct receptor complexes. We have previously found that the small GTPase OsRac1 plays key roles in the signaling of OsCERK1, a PRR for fungal chitin, and of Pit, an NLR for rice blast fungus, and associates directly and indirectly with both of these immune receptors. In this study, using biochemical and bioimaging approaches, we revealed that OsRac1 formed two distinct receptor complexes with OsCERK1 and with Pit. Supporting this result, OsCERK1 and Pit utilized different transport systems for anchorage to the plasma membrane (PM). Activation of OsCERK1 and Pit led to OsRac1 activation and, concomitantly, OsRac1 shifted from a small to a large protein complex fraction. We also found that the chaperone Hsp90 contributed to the proper transport of Pit to the PM and the immune induction of Pit. These findings illuminate how the PRR OsCERK1 and the NLR Pit orchestrate rice immunity through the small GTPase OsRac1.
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Affiliation(s)
- Akira Akamatsu
- Department of Biosciences, Kwansei Gakuin University, 2-1 Gakuen, Hyogo, 669-1337, Japan
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Masayuki Fujiwara
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
- Yanmar Holdings Co., Ltd, 1-32 Chayamachi, Kita Ward, Osaka 530-8311, Japan
| | - Satoshi Hamada
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Megumi Wakabayashi
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
- Field Solutions North East Asia, Agronomic Operations Japan, Agronomic Technology Station East Japan, Bayer Crop Science K.K., 9511-4 Yuki, Ibaraki 307-0001, Japan
| | - Ai Yao
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Qiong Wang
- Department of Horticulture and Plant Protection, Yangzhou University, Yangzhou 225009, China
| | - Ken-Ichi Kosami
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, No. 3888 Chenhua Road, Shanghai 201602, China
- Fruit Tree Research Center, Ehime Research Institute of Agriculture, Forestry and Fisheries, Matsuyama, 1618 Shimoidaicho, Ehime 791-0112, Japan
| | - Thu Thi Dang
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, No. 3888 Chenhua Road, Shanghai 201602, China
- IRHS-UMR1345, INRAE, Institut Agro, SFR 4207 QuaSaV, Université d'Angers, Beaucouzé 49071, France
| | - Takako Kaneko-Kawano
- College of Pharmaceutical Sciences, Ritsumeikan University, 1 Chome-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
| | - Fumi Fukada
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan
| | - Ko Shimamoto
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
| | - Yoji Kawano
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama-cho, Ikoma, Nara 630-0192, Japan
- CAS Center for Excellence in Molecular Plant Sciences, Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, No. 3888 Chenhua Road, Shanghai 201602, China
- Institute of Plant Science and Resources, Okayama University, Okayama 710-0046, Japan
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maiokachō, Totsuka Ward, Yokohama, Kanagawa 244-0813, Japan
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Liu J, Zhang L, Yan D. Plasmodesmata-Involved Battle Against Pathogens and Potential Strategies for Strengthening Hosts. FRONTIERS IN PLANT SCIENCE 2021; 12:644870. [PMID: 34149749 PMCID: PMC8210831 DOI: 10.3389/fpls.2021.644870] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Accepted: 04/28/2021] [Indexed: 06/01/2023]
Abstract
Plasmodesmata (PD) are membrane-lined pores that connect adjacent cells to mediate symplastic communication in plants. These intercellular channels enable cell-to-cell trafficking of various molecules essential for plant development and stress responses, but they can also be utilized by pathogens to facilitate their infection of hosts. Some pathogens or their effectors are able to spread through the PD by modifying their permeability. Yet plants have developed various corresponding defense mechanisms, including the regulation of PD to impede the spread of invading pathogens. In this review, we aim to illuminate the various roles of PD in the interactions between pathogens and plants during the infection process. We summarize the pathogenic infections involving PD and how the PD could be modified by pathogens or hosts. Furthermore, we propose several hypothesized and promising strategies for enhancing the disease resistance of host plants by the appropriate modulation of callose deposition and plasmodesmal permeability based on current knowledge.
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Affiliation(s)
- Jie Liu
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
| | - Lin Zhang
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of the Ministry of Education, Yangzhou University, Yangzhou, China
| | - Dawei Yan
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, China
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Lazareva EA, Lezzhov AA, Chergintsev DA, Golyshev SA, Dolja VV, Morozov SY, Heinlein M, Solovyev AG. Reticulon-like properties of a plant virus-encoded movement protein. THE NEW PHYTOLOGIST 2021; 229:1052-1066. [PMID: 32866987 DOI: 10.1111/nph.16905] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 08/20/2020] [Indexed: 06/11/2023]
Abstract
Plant viruses encode movement proteins (MPs) that ensure the transport of viral genomes through plasmodesmata (PD) and use cell endomembranes, mostly the endoplasmic reticulum (ER), for delivery of viral genomes to PD and formation of PD-anchored virus replication compartments. Here, we demonstrate that the Hibiscus green spot virus BMB2 MP, an integral ER protein, induces constrictions of ER tubules, decreases the mobility of ER luminal content, and exhibits an affinity to highly curved membranes. These properties are similar to those described for reticulons, cellular proteins that induce membrane curvature to shape the ER tubules. Similar to reticulons, BMB2 adopts a W-like topology within the ER membrane. BMB2 targets PD and increases their size exclusion limit, and these BMB2 activities correlate with the ability to induce constrictions of ER tubules. We propose that the induction of ER constrictions contributes to the BMB2-dependent increase in PD permeability and formation of the PD-associated replication compartments, therefore facilitating the virus intercellular spread. Furthermore, we show that the ER tubule constrictions also occur in cells expressing TGB2, one of the three MPs of Potato virus X (PVX), and in PVX-infected cells, suggesting that reticulon-like MPs are employed by diverse RNA viruses.
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Affiliation(s)
- Ekaterina A Lazareva
- Department of Virology, Biological Faculty, Moscow State University, Moscow, 119234, Russia
| | - Alexander A Lezzhov
- Faculty of Bioengineering and Bioinformatics, Moscow State University, Moscow, 119991, Russia
| | - Denis A Chergintsev
- Department of Plant Physiology, Biological Faculty, Moscow State University, Moscow, 119234, Russia
| | - Sergei A Golyshev
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119992, Russia
| | - Valerian V Dolja
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, 97331, USA
| | - Sergey Y Morozov
- Department of Virology, Biological Faculty, Moscow State University, Moscow, 119234, Russia
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119992, Russia
| | - Manfred Heinlein
- Institute for Plant Molecular Biology (IBMP-CNRS), University of Strasbourg, Strasbourg, 67000, France
| | - Andrey G Solovyev
- Department of Virology, Biological Faculty, Moscow State University, Moscow, 119234, Russia
- A.N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, 119992, Russia
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, 119991, Russia
- Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Moscow, 127550, Russia
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6
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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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7
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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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8
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Navarro JA, Sanchez-Navarro JA, Pallas V. Key checkpoints in the movement of plant viruses through the host. Adv Virus Res 2019; 104:1-64. [PMID: 31439146 DOI: 10.1016/bs.aivir.2019.05.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Plant viruses cannot exploit any of the membrane fusion-based routes of entry described for animal viruses. In addition, one of the distinctive structures of plant cells, the cell wall, acts as the first barrier against the invasion of pathogens. To overcome the rigidity of the cell wall, plant viruses normally take advantage of the way of life of different biological vectors. Alternatively, the physical damage caused by environmental stresses can facilitate virus entry. Once inside the cell and taking advantage of the characteristic symplastic continuity of plant cells, viruses need to remodel and/or modify the restricted pore size of the plasmodesmata (channels that connect plant cells). In a successful interaction for the virus, it can reach the vascular tissue to systematically invade the plant. The connections between the different cell types in this path are not designed to allow the passage of molecules with the complexity of viruses. During this process, viruses face different cell barriers that must be overcome to reach the distal parts of the plant. In this review, we highlight the current knowledge about how plant RNA viruses enter plant cells, move between them to reach vascular cells and overcome the different physical and cellular barriers that the phloem imposes. Finally, we update the current research on cellular organelles as key regulator checkpoints in the long-distance movement of plant viruses.
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Affiliation(s)
- Jose A Navarro
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Jesus A Sanchez-Navarro
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Vicente Pallas
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain.
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9
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Huang TK, Falk BW, Dandekar AM, McDonald KA. Enhancement of Recombinant Protein Production in Transgenic Nicotiana benthamiana Plant Cell Suspension Cultures with Co-Cultivation of Agrobacterium Containing Silencing Suppressors. Int J Mol Sci 2018; 19:E1561. [PMID: 29882931 PMCID: PMC6032394 DOI: 10.3390/ijms19061561] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 05/06/2018] [Accepted: 05/18/2018] [Indexed: 11/16/2022] Open
Abstract
We have previously demonstrated that the inducible plant viral vector (CMViva) in transgenic plant cell cultures can significantly improve the productivity of extracellular functional recombinant human alpha-1-antiryspin (rAAT) compared with either a common plant constitutive promoter (Cauliflower mosaic virus (CaMV) 35S) or a chemically inducible promoter (estrogen receptor-based XVE) system. For a transgenic plant host system, however, viral or transgene-induced post-transcriptional gene silencing (PTGS) has been identified as a host response mechanism that may dramatically reduce the expression of a foreign gene. Previous studies have suggested that viral gene silencing suppressors encoded by a virus can block or interfere with the pathways of transgene-induced PTGS in plant cells. In this study, the capability of nine different viral gene silencing suppressors were evaluated for improving the production of rAAT protein in transgenic plant cell cultures (CMViva, XVE or 35S system) using an Agrobacterium-mediated transient expression co-cultivation process in which transgenic plant cells and recombinant Agrobacterium carrying the viral gene silencing suppressor were grown together in suspension cultures. Through the co-cultivation process, the impacts of gene silencing suppressors on the rAAT production were elucidated, and promising gene silencing suppressors were identified. Furthermore, the combinations of gene silencing suppressors were optimized using design of experiments methodology. The results have shown that in transgenic CMViva cell cultures, the functional rAAT as a percentage of total soluble protein is increased 5.7 fold with the expression of P19, and 17.2 fold with the co-expression of CP, P19 and P24.
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Affiliation(s)
- Ting-Kuo Huang
- Department of Chemical Engineering and Materials Science, University of California, 1 Shields Avenue, Davis, CA 95616, USA.
| | - Bryce W Falk
- Department of Plant Pathology, University of California, 1 Shields Avenue, Davis, CA 95616, USA.
| | - Abhaya M Dandekar
- Department of Plant Sciences, University of California, 1 Shields Avenue, Davis, CA 95616, USA.
| | - Karen A McDonald
- Department of Chemical Engineering and Materials Science, University of California, 1 Shields Avenue, Davis, CA 95616, USA.
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10
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Solovyev AG, Morozov SY. Non-replicative Integral Membrane Proteins Encoded by Plant Alpha-Like Viruses: Emergence of Diverse Orphan ORFs and Movement Protein Genes. FRONTIERS IN PLANT SCIENCE 2017; 8:1820. [PMID: 29163564 PMCID: PMC5663686 DOI: 10.3389/fpls.2017.01820] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2017] [Accepted: 10/06/2017] [Indexed: 06/07/2023]
Abstract
Fast accumulation of sequencing data on plant virus genomes and plant transcriptomes demands periodic re-evaluation of current views on the genome evolution of viruses. Here, we substantiate and further detail our previously mostly speculative model on the origin and evolution of triple gene block (TGB) encoding plant virus movement proteins TGB1, TGB2, and TGB3. Recent experimental data on functional competence of transport gene modules consisting of two proteins related to TGB1 and TGB2, as well as sequence analysis data on similarity of TGB2 and TGB3 encoded by a viral genome and virus-like RNAs identified in a plant transcriptomes, suggest that TGB evolution involved events of gene duplication and gene transfer between viruses. In addition, our analysis identified that plant RNA-seq data assembled into RNA virus-like contigs encode a significant variety of hydrophobic proteins. Functions of these orphan proteins are still obscure; however, some of them are obviously related to hydrophobic virion proteins of recently sequenced invertebrate (mostly insect) viruses, therefore supporting the current view on a common origin for many groups of plant and insect RNA-containing viruses. Moreover, these findings may suggest that the function of at least some orphan hydrophobic proteins is to provide plant viruses with the ability to infect insect hosts. In general, our observations emphasize that comparison of RNA virus sequences in a large variety of land plants and algae isolated geographically and ecologically may lead to experimental confirmation of previously purely speculative schemes of evolution of single genes, gene modules, and whole genomes.
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Affiliation(s)
- Andrey G. Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow, Russia
- Institute of Molecular Medicine, Sechenov First Moscow State Medical University, Moscow, Russia
| | - 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
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11
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Lozano I, Leiva AM, Jimenez J, Fernandez E, Carvajal-Yepes M, Cuervo M, Cuellar WJ. Resolution of cassava-infecting alphaflexiviruses: Molecular and biological characterization of a novel group of potexviruses lacking the TGB3 gene. Virus Res 2017; 241:53-61. [PMID: 28365210 DOI: 10.1016/j.virusres.2017.03.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Revised: 03/24/2017] [Accepted: 03/25/2017] [Indexed: 10/19/2022]
Abstract
Several potexviruses (Family Alphaflexiviridae) have been reported infecting cassava (Manihot esculenta Crantz) in the Americas. They were isolated from severely diseased plants during the last 30-40 years and include: Cassava common mosaic virus (CsCMV), Cassava Caribbean mosaic virus (CsCaMV), Cassava Colombian symptomless virus (CsCSV) and Cassava virus X (CsVX). However, their definitive classification as distinct species remains unresolved for several reasons, including the lack of sequence data and unavailability of samples from original isolates. This complicates disease diagnostics, cassava germplasm exchange certification, evaluation of virus cleaning protocols and epidemiological studies. Furthermore, a recently detected novel alphaflexivirus, indicates that cassava-infecting potexviruses may be more diverse. To solve the identity of these viruses, we started indexing samples from different parts of Colombia using different sets of PCR primers, antisera available and inoculation to indicator plants. Results show that there are three major phylogenetic groups of potexviruses infecting cassava, and they correspond to CsCMV, CsVX and the newly identified Cassava new alphaflexivirus (CsNAV). Bioassays and sequence analysis established that isolates of CsNAV and CsVX cause latent infections in different cassava landraces, they are not efficiently transmitted to the indicator plant Nicotiana benthamiana and they lack the gene 3 of the conserved potexviral 'triple gene block' (TGB). In contrast, all isolates of CsCMV (which have a characteristic potexvirus genome arrangement) caused Cassava Common Mosaic Disease (CCMD) in single infections and were efficiently transmitted to N. benthamiana. Although phylogenetic analysis of the replicase sequence placed CsNAV and CsVX as members of the Potexvirus genus, their distinct genome arrangement and biological characteristics suggest they can be considered as members of a separate taxonomic group.
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Affiliation(s)
- Ivan Lozano
- Agrobiodiversity Research Area (AgBio), International Center for Tropical Agriculture (CIAT), AA 6713, Cali, Colombia
| | - Ana M Leiva
- Agrobiodiversity Research Area (AgBio), International Center for Tropical Agriculture (CIAT), AA 6713, Cali, Colombia; Facultad de Ciencias Agropecuarias, Universidad Nacional de Colombia, Palmira, Colombia
| | - Jenyfer Jimenez
- Agrobiodiversity Research Area (AgBio), International Center for Tropical Agriculture (CIAT), AA 6713, Cali, Colombia; Facultad de Ciencias Agropecuarias, Universidad Nacional de Colombia, Palmira, Colombia
| | - Elizabeth Fernandez
- Sub-Dirección de Recursos Genéticos, Instituto Nacional de Innovación Agraria (INIA), Lima, Peru
| | - Monica Carvajal-Yepes
- Agrobiodiversity Research Area (AgBio), International Center for Tropical Agriculture (CIAT), AA 6713, Cali, Colombia
| | - Maritza Cuervo
- Agrobiodiversity Research Area (AgBio), International Center for Tropical Agriculture (CIAT), AA 6713, Cali, Colombia
| | - Wilmer J Cuellar
- Agrobiodiversity Research Area (AgBio), International Center for Tropical Agriculture (CIAT), AA 6713, Cali, Colombia.
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12
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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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13
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Lazareva EA, Lezzhov AA, Komarova TV, Morozov SY, Heinlein M, Solovyev AG. A novel block of plant virus movement genes. MOLECULAR PLANT PATHOLOGY 2017; 18:611-624. [PMID: 27118327 PMCID: PMC6638293 DOI: 10.1111/mpp.12418] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2016] [Revised: 04/14/2016] [Accepted: 04/21/2016] [Indexed: 05/10/2023]
Abstract
Hibiscus green spot virus (HGSV) is a recently discovered and so far poorly characterized bacilliform plant virus with a positive-stranded RNA genome consisting of three RNA species. Here, we demonstrate that the proteins encoded by the ORF2 and ORF3 in HGSV RNA2 are necessary and sufficient to mediate cell-to-cell movement of transport-deficient Potato virus X in Nicotiana benthamiana. These two genes represent a specialized transport module called a 'binary movement block' (BMB), and ORF2 and ORF3 are termed BMB1 and BMB2 genes. In agroinfiltrated epidermal cells of N. benthamiana, green fluorescent protein (GFP)-BMB1 fusion protein was distributed diffusely in the cytoplasm and the nucleus. However, in the presence of BMB2, GFP-BMB1 was directed to cell wall-adjacent elongated bodies at the cell periphery, to cell wall-embedded punctate structures co-localizing with callose deposits at plasmodesmata, and to cells adjacent to the initially transformed cell. Thus, BMB2 can mediate the transport of BMB1 to and through plasmodesmata. In general, our observations support the idea that cell-to-cell trafficking of movement proteins involves an initial delivery to membrane compartments adjacent to plasmodesmata, subsequent entry of the plasmodesmata cavity and, finally, transport to adjacent cells. This process, as an alternative to tubule-based transport, has most likely evolved independently in triple gene block (TGB), double gene block (DGB), BMB and the single gene-coded transport system.
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Affiliation(s)
| | - Alexander A. Lezzhov
- Department of Virology, Biological FacultyMoscow State UniversityMoscow119234Russia
| | - Tatiana V. Komarova
- A. N. Belozersky Institute of Physico‐Chemical Biology, Moscow State UniversityMoscow119992Russia
- N. I. Vavilov Institute of General Genetics, Russian Academy of ScienceMoscow119991Russia
| | - Sergey Y. Morozov
- Department of Virology, Biological FacultyMoscow State UniversityMoscow119234Russia
- A. N. Belozersky Institute of Physico‐Chemical Biology, Moscow State UniversityMoscow119992Russia
| | - Manfred Heinlein
- Centre National de la Recherche ScientifiqueInstitut de Biologie Moléculaire des Plantes (IBMP)Strasbourg67084France
| | - Andrey G. Solovyev
- A. N. Belozersky Institute of Physico‐Chemical Biology, Moscow State UniversityMoscow119992Russia
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14
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Ho TL, Lee HC, Chou YL, Tseng YH, Huang WC, Wung CH, Lin NS, Hsu YH, Chang BY. The cysteine residues at the C-terminal tail of Bamboo mosaic virus triple gene block protein 2 are critical for efficient plasmodesmata localization of protein 1 in the same block. Virology 2017; 501:47-53. [PMID: 27863274 DOI: 10.1016/j.virol.2016.11.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Accepted: 11/05/2016] [Indexed: 10/20/2022]
Abstract
The movement of some plant viruses are accomplished by three proteins encoded by a triple gene block (TGB). The second protein (TGBp2) in the block is a transmembrane protein. This study was aimed to unravel the mechanism underlying the relatively inefficient cell-to-cell movement of Bamboo mosaic virus (BaMV) caused by amino acid substitutions for the three Cys residues, Cys-109, Cys-112 and Cys-119, at the C-terminal tail of TGBp2. Results from confocal microscopy revealed that substitutions of the three Cys residues of TGBp2, especially Cys-109 and Cys-112, would reduce the efficiency of TGBp2- and TGBp3-dependent PD localization of TGBp1. Moreover, there is an additive effect of the substitutions on reducing the efficiency of PD localization of TGBp1. These results indicate that the Cys residues in the C-terminal tail region of TGBp2 participate in the TGBp2- and TGBp3-dependent PD localization of TGBp1, and thus influence the cell-to-cell movement capability of BaMV.
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Affiliation(s)
- Tsai-Ling Ho
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan, Republic of China
| | - Hsiang-Chi Lee
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung 40227, Taiwan, Republic of China; Ph.D. Program in Microbial Genomics, National Chung-Hsing University and Academia Sinica, Taiwan, Republic of China
| | - Yuan-Lin Chou
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan, Republic of China
| | - Yang-Hao Tseng
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan, Republic of China
| | - Wei-Cheng Huang
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan, Republic of China
| | - Chiung-Hua Wung
- Biotechnology Center, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Na-Sheng Lin
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung 40227, Taiwan, Republic of China; Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung 40227, Taiwan, Republic of China
| | - Ban-Yang Chang
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan, Republic of China.
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15
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Deficiency of the eIF4E isoform nCBP limits the cell-to-cell movement of a plant virus encoding triple-gene-block proteins in Arabidopsis thaliana. Sci Rep 2017; 7:39678. [PMID: 28059075 PMCID: PMC5216350 DOI: 10.1038/srep39678] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 11/25/2016] [Indexed: 01/19/2023] Open
Abstract
One of the important antiviral genetic strategies used in crop breeding is recessive resistance. Two eukaryotic translation initiation factor 4E family genes, eIF4E and eIFiso4E, are the most common recessive resistance genes whose absence inhibits infection by plant viruses in Potyviridae, Carmovirus, and Cucumovirus. Here, we show that another eIF4E family gene, nCBP, acts as a novel recessive resistance gene in Arabidopsis thaliana toward plant viruses in Alpha- and Betaflexiviridae. We found that infection by Plantago asiatica mosaic virus (PlAMV), a potexvirus, was delayed in ncbp mutants of A. thaliana. Virus replication efficiency did not differ between an ncbp mutant and a wild type plant in single cells, but viral cell-to-cell movement was significantly delayed in the ncbp mutant. Furthermore, the accumulation of triple-gene-block protein 2 (TGB2) and TGB3, the movement proteins of potexviruses, decreased in the ncbp mutant. Inoculation experiments with several viruses showed that the accumulation of viruses encoding TGBs in their genomes decreased in the ncbp mutant. These results indicate that nCBP is a novel member of the eIF4E family recessive resistance genes whose loss impairs viral cell-to-cell movement by inhibiting the efficient accumulation of TGB2 and TGB3.
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16
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Lezzhov AA, Gushchin VA, Lazareva EA, Vishnichenko VK, Morozov SY, Solovyev AG. Translation of the shallot virus X TGB3 gene depends on non-AUG initiation and leaky scanning. J Gen Virol 2015; 96:3159-3164. [PMID: 26296665 DOI: 10.1099/jgv.0.000248] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Triple gene block (TGB), a conserved gene module found in the genomes of many filamentous and rod-shaped plant viruses, encodes three proteins, TGB1, TGB2 and TGB3, required for viral cell-to-cell movement through plasmodesmata and systemic transport via the phloem. The genome of Shallot virus X, the type species of the genus Allexivirus, includes TGB1 and TGB2 genes, but contains no canonical ORF for TGB3 protein. However, a TGB3-like protein-encoding sequence lacking an AUG initiator codon has been found in the shallot virus X (ShVX) genome in a position typical for TGB3 genes. This putative TGB3 gene is conserved in all allexiviruses. Here, we carried out sequence analysis to predict possible non-AUG initiator codons in the ShVX TGB3-encoding sequence. We further used an agroinfiltration assay in Nicotiana benthamiana to confirm this prediction. Site-directed mutagenesis was used to demonstrate that the ShVX TGB3 could be translated on a bicistronic mRNA template via a leaky scanning mechanism.
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Affiliation(s)
- Alexander A Lezzhov
- Department of Genetics, Biotechnology, Plant Breeding and Seed Science, Russian State Agrarian University - Moscow Timiryazev Agricultural Academy, Moscow 127550, Russia
| | - Vladimir A Gushchin
- Department of Virology, Biological Faculty, Moscow State University, Moscow 119992, Russia
- Genetic Department, Russian Center of Forest Health, Pushkino 141207, Russia
| | - Ekaterina A Lazareva
- Department of Virology, Biological Faculty, Moscow State University, Moscow 119992, Russia
| | - Valery K Vishnichenko
- Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Moscow 127550, Russia
| | - Sergey Y Morozov
- Department of Virology, Biological Faculty, Moscow State University, Moscow 119992, Russia
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
| | - Andrey G Solovyev
- Institute of Agricultural Biotechnology, Russian Academy of Agricultural Sciences, Moscow 127550, Russia
- Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119992, Russia
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17
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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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18
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Abstract
The symplastic communication network established by plasmodesmata (PD) and connected phloem provides an essential pathway for spatiotemporal intercellular signaling in plant development but is also exploited by viruses for moving their genomes between cells in order to infect plants systemically. Virus movement depends on virus-encoded movement proteins (MPs) that target PD and therefore represent important keys to the cellular mechanisms underlying the intercellular trafficking of viruses and other macromolecules. Viruses and their MPs have evolved different mechanisms for intracellular transport and interaction with PD. Some viruses move from cell to cell by interacting with cellular mechanisms that control the size exclusion limit of PD whereas other viruses alter the PD architecture through assembly of specialized transport structures within the channel. Some viruses move between cells in the form of assembled virus particles whereas other viruses may interact with nucleic acid transport mechanisms to move their genomes in a non-encapsidated form. Moreover, whereas several viruses rely on the secretory pathway to target PD, other viruses interact with the cortical endoplasmic reticulum and associated cytoskeleton to spread infection. This chapter provides an introduction into viruses and their role in studying the diverse cellular mechanisms involved in intercellular PD-mediated macromolecular trafficking.
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Affiliation(s)
- Manfred Heinlein
- Institut de Biologie Moléculaire des Plantes (IBMP), Centre National de la Recherche Scientifique (CNRS), 12 rue du Général Zimmer, 67084, Strasbourg, France,
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19
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Kumar D, Kumar R, Hyun TK, Kim JY. Cell-to-cell movement of viruses via plasmodesmata. JOURNAL OF PLANT RESEARCH 2015; 128:37-47. [PMID: 25527904 DOI: 10.1007/s10265-014-0683-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/14/2014] [Indexed: 05/03/2023]
Abstract
Plant viruses utilize plasmodesmata (PD), unique membrane-lined cytoplasmic nanobridges in plants, to spread infection cell-to-cell and long-distance. Such invasion involves a range of regulatory mechanisms to target and modify PD. Exciting discoveries in this field suggest that these mechanisms are executed by the interaction between plant cellular components and viral movement proteins (MPs) or other virus-encoded factors. Striking working analogies exist among endogenous non-cell-autonomous proteins and viral MPs, in which not only do they all use PD to traffic, but also they exploit same regulatory components to exert their functions. Thus, this review discusses on the viral strategies to move via PD and the PD-regulatory mechanisms involved in viral pathogenesis.
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Affiliation(s)
- Dhinesh Kumar
- Division of Applied Life Science (BK21plus), Department of Biochemistry, Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, 27-306, 501 Jinju-Daero, Jinju, 660-701, Korea
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20
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Park MR, Jeong RD, Kim KH. Understanding the intracellular trafficking and intercellular transport of potexviruses in their host plants. FRONTIERS IN PLANT SCIENCE 2014; 5:60. [PMID: 24672528 PMCID: PMC3957223 DOI: 10.3389/fpls.2014.00060] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 02/06/2014] [Indexed: 05/22/2023]
Abstract
The movement of potexviruses through the cytoplasm to plasmodesmata (PD) and through PD to adjacent cells depends on the viral and host cellular proteins. Potexviruses encode three movement proteins [referred to as the triple gene block (TGB1-3)]. TGB1 protein moves cell-to-cell through PD and requires TGB2 and TGB3, which are endoplasmic reticulum (ER)-located proteins. TGB3 protein directs the movement of the ER-derived vesicles induced by TGB2 protein from the perinuclear ER to the cortical ER. TGB2 protein physically interacts with TGB3 protein in a membrane-associated form and also interacts with either coat protein (CP) or TGB1 protein at the ER network. Recent studies indicate that potexvirus movement involves the interaction between TGB proteins and CP with host proteins including membrane rafts. A group of host cellular membrane raft proteins, remorins, can serve as a counteracting membrane platform for viral ribonucleoprotein (RNP) docking and can thereby inhibit viral movement. The CP, which is a component of the RNP movement complex, is also critical for viral cell-to-cell movement through the PD. Interactions between TGB1 protein and/or the CP subunit with the 5'-terminus of genomic RNA [viral RNA (vRNA)] form RNP movement complexes and direct the movement of vRNAs through the PD. Recent studies show that tobacco proteins such as NbMPB2C or NbDnaJ-like proteins interact with the stem-loop 1 RNA located at the 5'-terminus of Potato virus X vRNA and regulate intracellular as well as intercellular movement. Although several host proteins that interact with vRNAs or viral proteins and that are crucial for vRNA transport have been screened and characterized, additional host proteins and details of viral movement remain to be characterized. In this review, we describe recent progress in understanding potexvirus movement within and between cells and how such movement is affected by interactions between vRNA/proteins and host proteins.
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Affiliation(s)
- Mi-Ri Park
- Department of Agricultural Biotechnology, Seoul National UniversitySeoul, South Korea
- Plant Genomics and Breeding Institute, Seoul National UniversitySeoul, South Korea
- Research Institute for Agriculture and Life Sciences, Seoul National UniversitySeoul, South Korea
| | - Rae-Dong Jeong
- Advanced Radiation Technology Institute, Korea Atomic Energy Research InstituteJeongeup, South Korea
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology, Seoul National UniversitySeoul, South Korea
- Plant Genomics and Breeding Institute, Seoul National UniversitySeoul, South Korea
- Research Institute for Agriculture and Life Sciences, Seoul National UniversitySeoul, South Korea
- *Correspondence: Kook-Hyung Kim, Department of Agricultural Biotechnology, Seoul National University, Seoul 151-921, South Korea e-mail:
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21
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Park MR, Seo JK, Kim KH. Viral and nonviral elements in potexvirus replication and movement and in antiviral responses. Adv Virus Res 2013; 87:75-112. [PMID: 23809921 DOI: 10.1016/b978-0-12-407698-3.00003-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In Potato virus X, a member of the genus Potexvirus, special sequences and structures at the 5' and 3' ends of the nontranslated region function as cis-acting elements for viral replication. These elements greatly affect interactions between viral RNAs and those between viral RNAs and host factors. The potexvirus genome encodes five open-reading frames. Viral replicase, which is required for the synthesis of viral RNA, binds viral RNA elements and host factors to form a viral replication complex at the host cellular membrane. The coat protein (CP) and three viral movement proteins (TGB1, TGB2, and TGB3) have critical roles in mediating cell-to-cell viral movement through plasmodesmata by virion formation or by nonvirion ribonucleoprotein (RNP) complex formation with viral movement proteins (TGBs). The RNP complex, like TGB1-CP-viral RNA, is associated with viral replicase and used for immediate reinitiation of viral replication in newly invaded cells. Higher plants have defense mechanisms against potexviruses such as Rx-mediated resistance and RNA silencing. The CP acts as an avirulence effector for plant defense mechanisms, while TGB1 functions as a viral suppressor of RNA silencing, which is the mechanism of innate immune resistance. Here, we describe recent findings concerning the involvement of viral and host factors in potexvirus replication and in antiviral responses to potexvirus infection.
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Affiliation(s)
- Mi-Ri Park
- Department of Agricultural Biotechnology, Plant Genomics and Breeding Institute, Seoul National University, Seoul, Republic of Korea
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22
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Tilsner J, Linnik O, Louveaux M, Roberts IM, Chapman SN, Oparka KJ. Replication and trafficking of a plant virus are coupled at the entrances of plasmodesmata. J Cell Biol 2013; 201:981-95. [PMID: 23798728 PMCID: PMC3691464 DOI: 10.1083/jcb.201304003] [Citation(s) in RCA: 125] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 05/16/2013] [Indexed: 02/04/2023] Open
Abstract
Plant viruses use movement proteins (MPs) to modify intercellular pores called plasmodesmata (PD) to cross the plant cell wall. Many viruses encode a conserved set of three MPs, known as the triple gene block (TGB), typified by Potato virus X (PVX). In this paper, using live-cell imaging of viral RNA (vRNA) and virus-encoded proteins, we show that the TGB proteins have distinct functions during movement. TGB2 and TGB3 established endoplasmic reticulum-derived membranous caps at PD orifices. These caps harbored the PVX replicase and nonencapsidated vRNA and represented PD-anchored viral replication sites. TGB1 mediated insertion of the viral coat protein into PD, probably by its interaction with the 5' end of nascent virions, and was recruited to PD by the TGB2/3 complex. We propose a new model of plant virus movement, which we term coreplicational insertion, in which MPs function to compartmentalize replication complexes at PD for localized RNA synthesis and directional trafficking of the virus between cells.
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Affiliation(s)
- Jens Tilsner
- Biomedical Sciences Research Complex, University of St Andrews, Fife KY16 9ST, Scotland, UK.
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23
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Chou YL, Hung YJ, Tseng YH, Hsu HT, Yang JY, Wung CH, Lin NS, Meng M, Hsu YH, Chang BY. The stable association of virion with the triple-gene-block protein 3-based complex of Bamboo mosaic virus. PLoS Pathog 2013; 9:e1003405. [PMID: 23754943 PMCID: PMC3675025 DOI: 10.1371/journal.ppat.1003405] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 04/22/2013] [Indexed: 12/03/2022] Open
Abstract
The triple-gene-block protein 3 (TGBp3) of Bamboo mosaic virus (BaMV) is an integral endoplasmic reticulum (ER) membrane protein which is assumed to form a membrane complex to deliver the virus intracellularly. However, the virus entity that is delivered to plasmodesmata (PD) and its association with TGBp3-based complexes are not known. Results from chemical extraction and partial proteolysis of TGBp3 in membrane vesicles revealed that TGBp3 has a right-side-out membrane topology; i.e., TGBp3 has its C-terminal tail exposed to the outer surface of ER. Analyses of the TGBp3-specific immunoprecipitate of Sarkosyl-extracted TGBp3-based complex revealed that TGBp1, TGBp2, TGBp3, capsid protein (CP), replicase and viral RNA are potential constituents of virus movement complex. Substantial co-fractionation of TGBp2, TGBp3 and CP, but not TGBp1, in the early eluted gel filtration fractions in which virions were detected after TGBp3-specific immunoprecipitation suggested that the TGBp2- and TGBp3-based complex is able to stably associate with the virion. This notion was confirmed by immunogold-labeling transmission electron microscopy (TEM) of the purified virions. In addition, mutational and confocal microscopy analyses revealed that TGBp3 plays a key role in virus cell-to-cell movement by enhancing the TGBp2- and TGBp3-dependent PD localization of TGBp1. Taken together, our results suggested that the cell-to-cell movement of potexvirus requires stable association of the virion cargo with the TGBp2- and TGBp3-based membrane complex and recruitment of TGBp1 to the PD by this complex.
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Affiliation(s)
- Yuan-Lin Chou
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Yi-Jing Hung
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Yang-Hao Tseng
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Hsiu-Ting Hsu
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Jun-Yi Yang
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Chiung-Hua Wung
- Biotechnology Center, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Na-Sheng Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Menghsiao Meng
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Ban-Yang Chang
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
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Sun X, Zhang C. A conserved C-terminal motif is essential for self-interaction of Barley stripe mosaic virus China strain TGB3 protein. Biochem Biophys Res Commun 2012; 426:153-7. [PMID: 22925891 DOI: 10.1016/j.bbrc.2012.08.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 08/11/2012] [Indexed: 10/28/2022]
Abstract
The triple gene block (TGB) 3 protein is essential for the cell-to-cell movement of Barley stripe mosaic virus (BSMV). Previous studies have shown that TGB3, together with TGB2, facilitates the movement of TGB1 to the plasma membrane. However, the interactions among the three proteins (i.e., TGB3, TGB1, and TGB2) have not been thoroughly understood. The interactions of BSMV China strain (BSMV-CH) TGB3 with itself and with other two TGB proteins were investigated using a Gal4-based yeast two-hybrid system and pull-down assays. The results show that neither TGB1 nor TGB2 interacts with TGB3. However, self-interaction was detected for TGB3. The C-terminal 37 amino acids (amino acids 87-123) containing a conserved C-terminal motif were found required for the self-interaction of TGB3. The roles of the novel property of BSMV-CH TGB3 in virus cell-to-cell movement were discussed.
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Affiliation(s)
- Xianchao Sun
- Chongqing Key Laboratory of Plant Disease Biology, College of Plant Protection, Southwest University, Chongqing 400715, China.
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25
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Lu Y, Yan F, Guo W, Zheng H, Lin L, Peng J, Adams MJ, Chen J. Garlic virus X 11-kDa protein granules move within the cytoplasm and traffic a host protein normally found in the nucleolus. MOLECULAR PLANT PATHOLOGY 2011; 12:666-76. [PMID: 21726366 PMCID: PMC6640471 DOI: 10.1111/j.1364-3703.2010.00699.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The subcellular localization of the 11-kDa protein (p11) encoded by ORF3 of Garlic virus X (GarVX; genus Allexivirus, family Alphaflexiviridae) was examined by confocal microscopy. Granules with intense fluorescence were visible on the endoplasmic reticulum when p11 fused with green or red fluorescent protein (GFP or RFP) was expressed in epidermal cells of Nicotiana benthamiana. Moreover, the p11-RFP granules moved in the cytoplasm, along the cell periphery and through the cell membranes to adjacent cells. A 17-kDa protein (p17) of garlic interacting with p11 was identified by yeast two-hybridization and bimolecular fluorescence complementation assay. When p17 fused to GFP was expressed in epidermal cells of N. benthamiana, it localized to the nucleolus. However, in the presence of GarVX p11, the distribution of p17 changed to that of p11, but did not appear to affect the pattern of movement of p11.
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Affiliation(s)
- Yuwen Lu
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, MOA and Zhejiang Provincial Key Laboratory of Plant Virology, Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China
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26
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Schoelz JE, Harries PA, Nelson RS. Intracellular transport of plant viruses: finding the door out of the cell. MOLECULAR PLANT 2011; 4:813-31. [PMID: 21896501 PMCID: PMC3183398 DOI: 10.1093/mp/ssr070] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2011] [Accepted: 07/18/2011] [Indexed: 05/03/2023]
Abstract
Plant viruses are a class of plant pathogens that specialize in movement from cell to cell. As part of their arsenal for infection of plants, every virus encodes a movement protein (MP), a protein dedicated to enlarging the pore size of plasmodesmata (PD) and actively transporting the viral nucleic acid into the adjacent cell. As our knowledge of intercellular transport has increased, it has become apparent that viruses must also use an active mechanism to target the virus from their site of replication within the cell to the PD. Just as viruses are too large to fit through an unmodified plasmodesma, they are also too large to be freely diffused through the cytoplasm of the cell. Evidence has accumulated now for the involvement of other categories of viral proteins in intracellular movement in addition to the MP, including viral proteins originally associated with replication or gene expression. In this review, we will discuss the strategies that viruses use for intracellular movement from the replication site to the PD, in particular focusing on the role of host membranes for intracellular transport and the coordinated interactions between virus proteins within cells that are necessary for successful virus spread.
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Affiliation(s)
- James E. Schoelz
- Division of Plant Sciences, University of Missouri, Columbia, MO 65211, USA
| | - Phillip A. Harries
- Department of Biology, Pittsburg State University, Pittsburg, KS 66762, USA
| | - Richard S. Nelson
- Plant Biology Division, The Samuel Roberts Noble Foundation, Inc., Ardmore, OK 73401, USA
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27
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Kaido M, Funatsu N, Tsuno Y, Mise K, Okuno T. Viral cell-to-cell movement requires formation of cortical punctate structures containing Red clover necrotic mosaic virus movement protein. Virology 2011; 413:205-15. [PMID: 21377183 DOI: 10.1016/j.virol.2011.02.008] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 01/27/2011] [Accepted: 02/05/2011] [Indexed: 01/30/2023]
Abstract
Movement protein (MP) of Red clover necrotic mosaic virus (RCNMV) forms punctate structures on the cortical endoplasmic reticulum (ER) of Nicotiana benthamiana cells, which are associated with viral RNA1 replication (Kaido et al., Virology 395, 232-242. 2009). We investigated the significance of ER-targeting by MP during virus movement from cell to cell, by analyzing the function of a series of MPs with varying length deletions at their C-terminus, either fused or not fused with green fluorescent protein (GFP). The C-terminal 70 amino acids were crucial to ER-localization of MP-GFP and cell-to-cell movement of the recombinant virus encoding it. However, C-terminal deletion did not affect MP functions, such as increasing the size exclusion limit of plasmodesmata, single-stranded RNA binding in vitro, and MP interacting in vivo. We discuss the possible role of this MP region in virus movement from cell to cell.
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Affiliation(s)
- Masanori Kaido
- Laboratory of Plant Pathology, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan.
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28
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Hyun TK, Uddin MN, Rim Y, Kim JY. Cell-to-cell trafficking of RNA and RNA silencing through plasmodesmata. PROTOPLASMA 2011; 248:101-16. [PMID: 21042816 DOI: 10.1007/s00709-010-0225-6] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Accepted: 10/14/2010] [Indexed: 05/05/2023]
Abstract
Plasmodesmata (PD) are plasma membrane-lined cytoplasmic channels that cross the cell wall and establish symplasmic continuity between neighboring cells in plants. Recently, a wide range of cellular RNAs (including mRNAs and small RNAs (sRNAs)) have been reported to move from cell to cell through PD trafficking pathways. sRNAs are key molecules that function in transcriptional and post-transcriptional RNA silencing, which is a gene expression regulatory mechanism that is conserved among eukaryotes and is important for protection against invading nucleic acids (such as viruses and transposons) and for developmental and physiological regulation. One of the most intriguing aspects of RNA silencing is that it can function either cell autonomously or non-cell autonomously in post-transcriptional RNA silencing pathways. Although the mechanisms underlying cell-to-cell trafficking of RNA and RNA silencing signals are not fully understood, the movement of specific RNAs seems to play a critical role in cell-to-cell and long-distance regulation of gene expression, thereby coordinating growth and developmental processes, gene silencing, and stress responses. In this review, we summarize the current knowledge regarding cell-to-cell trafficking of RNA molecules (including small RNAs), and we discuss potential molecular mechanisms of cell-to-cell trafficking that are mediated by complex networks.
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Affiliation(s)
- Tae Kyung Hyun
- Department of Biochemistry, Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju, 660-701, South Korea
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29
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Abstract
Plant viruses exploit cellular factors, including host proteins, membranes and metabolites, for their replication in infected cells and to establish systemic infections. Besides traditional genetic, molecular, cellular and biochemical methods studying plant-virus interactions, both global and specialized proteomics methods are emerging as useful approaches for the identification of all the host proteins that play roles in virus infections. The various proteomics approaches include measuring differential protein expression in virus infected versus noninfected cells, analysis of viral and host protein components in the viral replicase or other virus-induced complexes, as well as proteome-wide screens to identify host protein - viral protein interactions using protein arrays or yeast two-hybrid assays. In this review, we will discuss the progress made in plant virology using various proteomics methods, and highlight the functions of some of the identified host proteins during viral infections. Since global proteomics approaches do not usually identify the molecular mechanism of the identified host factors during viral infections, additional experiments using genetics, biochemistry, cell biology and other approaches should also be performed to characterize the functions of host factors. Overall, the ever-improving proteomics approaches promise further understanding of plant-virus interactions that will likely result in new strategies for viral disease control in plants.
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Affiliation(s)
- Kai Xu
- Department of Plant Pathology, University of Kentucky, Lexington, KY
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30
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Benitez-Alfonso Y, Faulkner C, Ritzenthaler C, Maule AJ. Plasmodesmata: gateways to local and systemic virus infection. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1403-12. [PMID: 20687788 DOI: 10.1094/mpmi-05-10-0116] [Citation(s) in RCA: 119] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
As channels that provide cell-to-cell connectivity, plasmodesmata are central to the local and systemic spread of viruses in plants. This review discusses the current state of knowledge of the structure and function of these channels and the ways in which viruses bring about functional changes that allow macromolecular trafficking to occur. Despite the passing of two decades since the first identification of a viral movement protein that mediates these changes, our understanding of the relevant molecular mechanisms remains in its infancy. However, viral movement proteins provide valuable tools for the modification of plasmodesmata and will continue to assist in the dissection of plasmodesmal properties in relation to their core roles in cell-to-cell communication.
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31
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Verchot-Lubicz J, Torrance L, Solovyev AG, Morozov SY, Jackson AO, Gilmer D. Varied movement strategies employed by triple gene block-encoding viruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2010; 23:1231-47. [PMID: 20831404 DOI: 10.1094/mpmi-04-10-0086] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Several RNA virus genera belonging to the Virgaviridae and Flexiviridae families encode proteins organized in a triple gene block (TGB) that facilitate cell-to-cell and long-distance movement. The TGB proteins have been traditionally classified as hordei-like or potex-like based on phylogenetic comparisons and differences in movement mechanisms of the Hordeivirus and Potexvirus spp. However, accumulating data from other model viruses suggests that a revised framework is needed to accommodate the profound differences in protein interactions occurring during infection and ancillary capsid protein requirements for movement. The goal of this article is to highlight common features of the TGB proteins and salient differences in movement properties exhibited by individual viruses encoding these proteins. We discuss common and divergent aspects of the TGB transport machinery, describe putative nucleoprotein movement complexes, highlight recent data on TGB protein interactions and topological properties, and review membrane associations occurring during subcellular targeting and cell-to-cell movement. We conclude that the existing models cannot be used to explain all TGB viruses, and we propose provisional Potexvirus, Hordeivirus, and Pomovirus models. We also suggest areas that might profit from future research on viruses harboring this intriguing arrangement of movement proteins.
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Affiliation(s)
- Jeanmarie Verchot-Lubicz
- Oklahoma State University, Department of Entomology and Plant Pathology, Stillwater, OK 74078, USA.
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32
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Epel BL. Plant viruses spread by diffusion on ER-associated movement-protein-rafts through plasmodesmata gated by viral induced host β-1,3-glucanases. Semin Cell Dev Biol 2009; 20:1074-81. [DOI: 10.1016/j.semcdb.2009.05.010] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2009] [Revised: 05/24/2009] [Accepted: 05/27/2009] [Indexed: 01/24/2023]
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33
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Lim HS, Bragg JN, Ganesan U, Ruzin S, Schichnes D, Lee MY, Vaira AM, Ryu KH, Hammond J, Jackson AO. Subcellular localization of the barley stripe mosaic virus triple gene block proteins. J Virol 2009; 83:9432-48. [PMID: 19570874 PMCID: PMC2738231 DOI: 10.1128/jvi.00739-09] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Accepted: 06/22/2009] [Indexed: 02/07/2023] Open
Abstract
Barley stripe mosaic virus (BSMV) spreads from cell to cell through the coordinated actions of three triple gene block (TGB) proteins (TGB1, TGB2, and TGB3) arranged in overlapping open reading frames (ORFs). Our previous studies (D. M. Lawrence and A. O. Jackson, J. Virol. 75:8712-8723, 2001; D. M. Lawrence and A. O. Jackson, Mol. Plant Pathol. 2:65-75, 2001) have shown that each of these proteins is required for cell-to-cell movement in monocot and dicot hosts. We recently found (H.-S. Lim, J. N. Bragg, U. Ganesan, D. M. Lawrence, J. Yu, M. Isogai, J. Hammond, and A. O. Jackson, J. Virol. 82:4991-5006, 2008) that TGB1 engages in homologous interactions leading to the formation of a ribonucleoprotein complex containing viral genomic and messenger RNAs, and we have also demonstrated that TGB3 functions in heterologous interactions with TGB1 and TGB2. We have now used Agrobacterium tumefaciens-mediated protein expression in Nicotiana benthamiana leaf cells and site-specific mutagenesis to determine how TGB protein interactions influence their subcellular localization and virus spread. Confocal microscopy revealed that the TGB3 protein localizes at the cell wall (CW) in close association with plasmodesmata and that the deletion or mutagenesis of a single amino acid at the immediate C terminus can affect CW targeting. TGB3 also directed the localization of TGB2 from the endoplasmic reticulum to the CW, and this targeting was shown to be dependent on interactions between the TGB2 and TGB3 proteins. The optimal localization of the TGB1 protein at the CW also required TGB2 and TGB3 interactions, but in this context, site-specific TGB1 helicase motif mutants varied in their localization patterns. The results suggest that the ability of TGB1 to engage in homologous binding interactions is not essential for targeting to the CW. However, the relative expression levels of TGB2 and TGB3 influenced the cytosolic and CW distributions of TGB1 and TGB2. Moreover, in both cases, localization at the CW was optimal at the 10:1 TGB2-to-TGB3 ratios occurring in virus infections, and mutations reducing CW localization had corresponding effects on BSMV movement phenotypes. These data support a model whereby TGB protein interactions function in the subcellular targeting of movement protein complexes and the ability of BSMV to move from cell to cell.
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Affiliation(s)
- Hyoun-Sub Lim
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Jennifer N. Bragg
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Uma Ganesan
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Steven Ruzin
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Denise Schichnes
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Mi Yeon Lee
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Anna Maria Vaira
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Ki Hyun Ryu
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - John Hammond
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
| | - Andrew O. Jackson
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, FNPRU, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, CNR, Istituto di Virologia Vegetale, Torino 10135, Italy, Plant Virus GenBank, Division of Environmental and Life Sciences, Seoul Women's University, Seoul 139-774, South Korea
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Lu HC, Chen CE, Tsai MH, Wang HI, Su HJ, Yeh HH. Cymbidium mosaic potexvirus isolate-dependent host movement systems reveal two movement control determinants and the coat protein is the dominant. Virology 2009; 388:147-59. [PMID: 19345971 PMCID: PMC7103407 DOI: 10.1016/j.virol.2009.02.049] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2008] [Revised: 01/28/2009] [Accepted: 02/28/2009] [Indexed: 11/30/2022]
Abstract
Little is known about how plant viruses of a single species exhibit different movement behavior in different host species. Two Cymbidium mosaic potexvirus (CymMV) isolates, M1 and M2, were studied. Both can infect Phalaenopsis orchids, but only M1 can systemically infect Nicotiana benthamiana plants. Protoplast inoculation and whole-mount in situ hybridization revealed that both isolates can replicate in N. benthamiana; however, M2 was restricted to the initially infected cells. Genome shuffling between M1 and M2 revealed that two control modes are involved in CymMV host dependent movement. The M1 coat protein (CP) plays a dominant role in controlling CymMV movement between cells, because all chimeric CymMV viruses containing the M1 CP systemically infected N. benthamiana plants. Without the M1 CP, one chimeric virus containing the combination of the M1 triple gene block proteins (TGBps), the M2 5' RNA (1-4333), and the M2 CP effectively moved in N. benthamiana plants. Further complementation analysis revealed that M1 TGBp1 and TGBp3 are co-required to complement the movement of the chimeric viruses in N. benthamiana. The amino acids within the CP, TGBp1 and TGBp3 which are required or important for CymMV M2 movement in N. benthamiana plants were mapped. The required amino acids within the CP map to the predicted RNA binding domain. RNA-protein binding assays revealed that M1 CP has higher RNA binding affinity than does M2 CP. Yeast two-hybrid assays to detect all possible interactions of M1 TGBps and CP, and only TGBp1 and CP self-interactions were observed.
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Affiliation(s)
- Hsiang-Chia Lu
- Department of Plant Pathology and Microbiology, National Taiwan University, 1, sec 4, Roosevelt Road, Taipei 106, Taiwan
| | - Cheng-En Chen
- Department of Plant Pathology and Microbiology, National Taiwan University, 1, sec 4, Roosevelt Road, Taipei 106, Taiwan
| | - Meng-Hsiun Tsai
- Department of Management Information Systems, National Chung Hsing University, 250, Kuo Kuang Rd., Taichung 402, Taiwan
| | - Hsiang-iu Wang
- Department of Computer Science, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan
| | - Hong-Ji Su
- Department of Plant Pathology and Microbiology, National Taiwan University, 1, sec 4, Roosevelt Road, Taipei 106, Taiwan
| | - Hsin-Hung Yeh
- Department of Plant Pathology and Microbiology, National Taiwan University, 1, sec 4, Roosevelt Road, Taipei 106, Taiwan
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35
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Hsu HT, Tseng YH, Chou YL, Su SH, Hsu YH, Chang BY. Characterization of the RNA-binding properties of the triple-gene-block protein 2 of Bamboo mosaic virus. Virol J 2009; 6:50. [PMID: 19422690 PMCID: PMC2689192 DOI: 10.1186/1743-422x-6-50] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Accepted: 05/07/2009] [Indexed: 11/10/2022] Open
Abstract
The triple-gene-block protein 2 (TGBp2) of Bamboo mosaic virus (BaMV) is a transmembrane protein which was proposed to be involved in viral RNA binding during virus transport. Here, we report on the RNA-binding properties of TGBp2. Using tyrosine fluorescence spectroscopy and UV-crosslinking assays, the TGBp2 solubilized with Triton X-100 was found to interact with viral RNA in a non-specific manner. These results raise the possibility that TGBp2 facilitates intracellular delivery of viral RNA through non-specific protein-RNA interaction.
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Affiliation(s)
- Hsiu-Ting Hsu
- Institute of Biochemistry, National Chung-Hsing University, Taichung 40227, Taiwan, PR China.
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Jackson AO, Lim HS, Bragg J, Ganesan U, Lee MY. Hordeivirus replication, movement, and pathogenesis. ANNUAL REVIEW OF PHYTOPATHOLOGY 2009; 47:385-422. [PMID: 19400645 DOI: 10.1146/annurev-phyto-080508-081733] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The last Hordeivirus review appearing in this series 20 years ago focused on the comparative biology, relationships, and genome organization of members of the genus ( 68 ). Prior to the 1989 review, useful findings about the origin, disease occurrence, host ranges, and general biological properties of Barley stripe mosaic virus (BSMV) were summarized in three comprehensive reviews ( 26, 67, 107 ). Several recent reviews emphasizing contemporary molecular genetic findings also may be of interest to various readers ( 15, 37, 42, 69, 70, 88, 113 ). In the current review, we briefly reiterate the biological properties of the four members of the Hordeivirus genus and describe advances in our understanding of organization and expression of the viral genomes. We also discuss the infection processes and pathogenesis of the most extensively characterized Hordeiviruses and frame these advances in the broader context of viruses in other families that have encoded triple gene block proteins. In addition, an overview of recent advances in the use of BSMV for virus-induced gene silencing is presented.
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Affiliation(s)
- Andrew O Jackson
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA.
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37
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Abstract
Plant viruses spread from the initially infected cells to the rest of the plant in several distinct stages. First, the virus (in the form of virions or nucleic acid protein complexes) moves intracellularly from the sites of replication to plasmodesmata (PD, plant-specific intercellular membranous channels), the virus then transverses the PD to spread intercellularly (cell-to-cell movement). Long-distance movement of virus occurs through phloem sieve tubes. The processes of plant virus movement are controlled by specific viral movement proteins (MPs). No extensive sequence similarity has been found in MPs belonging to different plant virus taxonomic groups. Moreover, different MPs were shown to use different pathways and mechanisms for virus transport. Some viral transport systems require a single MP while others require additional virus-encoded proteins to transport viral genomes. In this review, we focus on the functions and properties of different classes of MPs encoded by RNA containing plant viruses.
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Haupt S, Ziegler A, Torrance L. Localization of viral proteins in plant cells: protein tagging. Methods Mol Biol 2008; 451:463-73. [PMID: 18370274 DOI: 10.1007/978-1-59745-102-4_31] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2023]
Abstract
This chapter describes techniques for in vivo imaging of fluorescent fusion proteins in living cells by confocal laser scanning microscopy (CLSM). Methods are provided for (i) producing the constructs for transient expression from plasmids or virus-based vectors, (ii) introduction of constructs to plant epidermal cells; (iii) imaging of the expressed proteins by CLSM and image processing, and (iv) studying the expression in the presence of agents that affect the integrity or function of cytoskeletal elements. Notes are provided to aid comprehension and indicate problems.
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Affiliation(s)
- Sophie Haupt
- University of Dundee at SCRI, Invergowrie, DD2 5DA, UK
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Samuels TD, Ju HJ, Ye CM, Motes CM, Blancaflor EB, Verchot-Lubicz J. Subcellular targeting and interactions among the Potato virus X TGB proteins. Virology 2007; 367:375-89. [PMID: 17610926 DOI: 10.1016/j.virol.2007.05.022] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2007] [Revised: 04/24/2007] [Accepted: 05/03/2007] [Indexed: 12/16/2022]
Abstract
Potato virus X (PVX) encodes three proteins named TGBp1, TGBp2, and TGBp3 which are required for virus cell-to-cell movement. To determine whether PVX TGB proteins interact during virus cell-cell movement, GFP was fused to each TGB coding sequence within the viral genome. Confocal microscopy was used to study subcellular accumulation of each protein in virus-infected plants and protoplasts. GFP:TGBp2 and TGBp3:GFP were both seen in the ER, ER-associated granular vesicles, and perinuclear X-bodies suggesting that these proteins interact in the same subdomains of the endomembrane network. When plasmids expressing CFP:TGBp2 and TGBp3:GFP were co-delivered to tobacco leaf epidermal cells, the fluorescent signals overlapped in ER-associated granular vesicles indicating that these proteins colocalize in this subcellular compartment. GFP:TGBp1 was seen in the nucleus, cytoplasm, rod-like inclusion bodies, and in punctate sites embedded in the cell wall. The puncta were reminiscent of previous reports showing viral proteins in plasmodesmata. Experiments using CFP:TGBp1 and YFP:TGBp2 or TGBp3:GFP showed CFP:TGBp1 remained in the cytoplasm surrounding the endomembrane network. There was no evidence that the granular vesicles contained TGBp1. Yeast two hybrid experiments showed TGBp1 self associates but failed to detect interactions between TGBp1 and TGBp2 or TGBp3. These experiments indicate that the PVX TGB proteins have complex subcellular accumulation patterns and likely cooperate across subcellular compartments to promote virus infection.
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Affiliation(s)
- Timmy D Samuels
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK 74078, USA
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40
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Wang K, Kang L, Anand A, Lazarovits G, Mysore KS. Monitoring in planta bacterial infection at both cellular and whole-plant levels using the green fluorescent protein variant GFPuv. THE NEW PHYTOLOGIST 2007; 174:212-223. [PMID: 17335510 DOI: 10.1111/j.1469-8137.2007.01999.x] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
* Green fluorescent protein (GFP) labeling of bacteria has been used to study their infection of and localization in plants, but strong autofluorescence from leaves and the relatively weak green fluorescence of GFP-labeled bacteria restrict its broader application to investigations of plant-bacterial interactions. * A stable and broad-host-range plasmid vector (pDSK-GFPuv) that strongly expresses GFPuv protein was constructed not only for in vivo monitoring of bacterial infection, localization, activity, and movement at the cellular level under fluorescence microscopy, but also for monitoring bacterial disease development at the whole-plant level under long-wavelength ultraviolet (UV) light. * The presence of pDSK-GFPuv did not have significant impact on the in vitro or in planta growth and virulence of phytobacteria. A good correlation between bacterial cell number and fluorescence intensity was observed, which allowed us to rapidly estimate the bacterial population in plant leaf tissue. We demonstrated that GFPuv-expressing bacteria can be used to screen plants that are compromised for nonhost disease resistance and Agrobacterium attachment. * The use of GFPuv-labeled bacteria has a wide range of applications in host-bacterial interaction studies and bacterial ecology-related research.
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Affiliation(s)
- Keri Wang
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA
| | - Li Kang
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA
| | - Ajith Anand
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA
| | - George Lazarovits
- Southern Crop Protection and Food Research Center, Agriculture and Agri-Food Canada, 1391 Sandford Street, London, ON N5V 4T3, Canada
| | - Kirankumar S Mysore
- Plant Biology Division, The Samuel Roberts Noble Foundation, 2510 Sam Noble Parkway, Ardmore, OK 73401, USA
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41
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Uhde-Holzem K, Fischer R, Commandeur U. Genetic stability of recombinant potato virus X virus vectors presenting foreign epitopes. Arch Virol 2006; 152:805-11. [PMID: 17216135 DOI: 10.1007/s00705-006-0892-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2006] [Accepted: 11/06/2006] [Indexed: 10/23/2022]
Abstract
We investigated the genetic stability of recombinant potato virus X vectors presenting beet necrotic yellow vein virus (BNYVV) epitopes. Following N-terminal PVX coat protein (CP) fusion of the BNYVV epitopes, we inoculated Nicotiana benthamiana plants with recombinant (r)PVX and carried out five serial passages through systemically-infected plants. RT-PCR investigation of the BNYVV epitope sequences revealed the accumulation of several point mutations and deletions, predominantly affecting positively-charged residues. A comparison of the isoelectric point (pI) values and charges of the wild type and rCPs showed that the initial high rCP pI values had changed to values closer to that of the wild-type CP.
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Affiliation(s)
- K Uhde-Holzem
- Institute for Molecular Biotechnology, RWTH Aachen University, Aachen, Germany
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Zhou T, Fan ZF, Li HF, Wong SM. Hibiscus chlorotic ringspot virus p27 and its isoforms affect symptom expression and potentiate virus movement in kenaf (Hibiscus cannabinus L.). MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2006; 19:948-57. [PMID: 16941899 DOI: 10.1094/mpmi-19-0948] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Hibiscus chlorotic ringspot virus (HCRSV), a member of the genus Carmovirus, encodes p27 (27-kDa protein) and two other in-frame isoforms (p25 and p22.5) that are coterminal at the carboxyl end. Only p27, which initiates at the 2570CUG codon, was detected in transfected kenaf (Hibiscus cannabinus L.) protoplasts through fusion to a Flag tag at either its N or C terminus. Subcellular localization of a p27-green fluorescent fusion protein in kenaf epidermal cells showed that it was localized to membrane structures close to cell walls. To study the functions of these proteins, a number of start codon mutants and premature translation termination mutants were constructed. Phenotypic differences were observed between the wild-type virus and these mutants during infection. Infectivity assays on plants indicated that p27 is a determinant of symptom severity. Without p25, appearance of symptoms on systemically infected kenaf leaves was delayed by 4 to 8 days. In a timecourse analysis, Western blot assays revealed that the delay corresponded to retardation in virus systemic movement, which suggested that p25 is probably involved in virus systemic movement. Mutations disrupting expression of p22.5 did not affect symptoms or virus movement.
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Affiliation(s)
- T Zhou
- Department of Plant Pathology, State Key Laboratory of Agrobiotechnology [corrected] China Agricultural University, Beijing 100094, China
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43
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Lough TJ, Lee RH, Emerson SJ, Forster RLS, Lucas WJ. Functional analysis of the 5' untranslated region of potexvirus RNA reveals a role in viral replication and cell-to-cell movement. Virology 2006; 351:455-65. [PMID: 16697024 DOI: 10.1016/j.virol.2006.03.043] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2006] [Revised: 03/06/2006] [Accepted: 03/27/2006] [Indexed: 11/27/2022]
Abstract
Cell-to-cell movement of potexviruses requires cognate recognition between the viral RNA, the triple gene block proteins (TGBp1-3) and the coat protein (CP). cis-acting motifs required for recognition and translocation of viral RNA were identified using an artificial potexvirus defective RNA encoding a green fluorescent protein (GFP) reporter transcriptionally fused to the terminal viral sequences. Analysis of GFP fluorescence produced in vivo from these defective RNA constructs, referred to as chimeric RNA reporters, was used to identify viral cis-acting motifs required for RNA trafficking. Mapping experiments localized the cis-acting element to nucleotides 1-107 of the Potato virus X (PVX) genome. This sequence forms an RNA secondary structural element that has also been implicated in viral plus-strand accumulation [Miller, E.D., Plante, C.A., Kim, K.-H., Brown, J.W. and Hemenway, C. (1998) J. Mol. Biol. 284, 591-608]. While replication and movement functions associated with this region have not been separated, these results are consistent with sequence-specific recognition of RNA by the viral movement protein(s). This situation is unusual among viral movement proteins that typically function to translocate RNA between cells in a non-sequence-specific manner. These data support the concept of cis-acting elements specifying intercellular potexvirus RNA movement and thus provide a basis for dissection of RNA-mediated intercellular communication in plants.
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Affiliation(s)
- Tony J Lough
- Horticulture and Food Research Institute of New Zealand, Plant Health and Development Group, Private Bag 11030, Palmerston North, New Zealand.
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44
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Lin MK, Hu CC, Lin NS, Chang BY, Hsu YH. Movement of potexviruses requires species-specific interactions among the cognate triple gene block proteins, as revealed by a trans-complementation assay based on the bamboo mosaic virus satellite RNA-mediated expression system. J Gen Virol 2006; 87:1357-1367. [PMID: 16603539 DOI: 10.1099/vir.0.81625-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The intra- and intercellular transport of potexviruses require interactions among viral RNA, coat protein and elements of the triple gene block proteins (TGBps). In this study, the requirement of bamboo mosaic virus (BaMV) TGBps for movement functions and the compatibilities with those of two potexviruses, Potato virus X (PVX) and Foxtail mosaic virus (FoMV), were examined using a satellite RNA-mediated trans-complementation assay system. Single or multiple TGBps of BaMV, PVX and FoMV were expressed from BaMV satellite RNA (satBaMV RNA) vectors to complement the functions of green fluorescent protein-tagged, movement-defective BaMV with mutation(s) in the matching gene(s). It was found that individual BaMV TGBps expressed from the satellite vector could function normally in trans, whereas bi-gene BaMV TGBp constructs in which the expression of TGBp3 might be impaired and individual TGBp genes from PVX or FoMV could not complement the movement functions of the defective helper viruses. Furthermore, alterations of the ratio among TGBps by ectopic expression of individual components of TGBps from satBaMV RNA vectors did not affect the cell-to-cell movement capabilities of wild-type BaMV significantly. The results indicate that species-specific interactions among movement proteins are obligatory for the cell-to-cell movement of BaMV and possibly other potexviruses.
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Affiliation(s)
- Ming-Kuem Lin
- Graduate Institute of Biotechnology, National Chung-Hsing University, 250 Kuo-Kuang Road, Taichung City, Taiwan 402, ROC
| | - Chung-Chi Hu
- Graduate Institute of Biotechnology, National Chung-Hsing University, 250 Kuo-Kuang Road, Taichung City, Taiwan 402, ROC
| | - Na-Sheng Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei, Taiwan 115, ROC
| | - Ban-Yang Chang
- Graduate Institute of Biochemistry, National Chung-Hsing University, 250 Kuo-Kuang Road, Taichung City, Taiwan 402, ROC
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung-Hsing University, 250 Kuo-Kuang Road, Taichung City, Taiwan 402, ROC
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45
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Lucas WJ. Plant viral movement proteins: Agents for cell-to-cell trafficking of viral genomes. Virology 2006; 344:169-84. [PMID: 16364748 DOI: 10.1016/j.virol.2005.09.026] [Citation(s) in RCA: 317] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Accepted: 09/10/2005] [Indexed: 10/25/2022]
Abstract
Plants viruses spread throughout their hosts using a number of pathways, the most common being movement cell to cell through plasmodesmata (PD), unique intercellular organelles of the plant kingdom, and between organs by means of the vascular system. Pioneering studies on plant viruses revealed that PD allow the cell-to-cell trafficking of virally encoded proteins, termed the movement proteins (MPs). This non-cell-autonomous protein (NCAP) pathway is similarly employed by the host to traffic macromolecules. Viral MPs bind RNA/DNA in a sequence nonspecific manner to form nucleoprotein complexes (NPC). Host proteins are then involved in the delivery of MPs and NPC to the PD orifice, and a role for the cytoskeleton has been implicated. Trafficking of NCAPs through the PD structure involves three steps in which the MP: (a) interacts with a putative PD docking complex, (b) induces dilation in the PD microchannels, and (c) binds to an internal translocation system for delivery into the neighboring cytoplasm. Viral genera that use this NCAP pathway have evolved a combination of a MP and ancillary proteins that work in concert to enable the formation of a stable NPC that can compete with endogenous NCAPs for the PD trafficking machinery. Incompatible MP-host protein interactions may underlie observed tissue tropisms and restricted infection domains. These pivotal discoveries are discussed in terms of the need to develop a more comprehensive understanding of the (a) three-dimensional structure of MPs, (b) PD supramolecular complex, and (c) host proteins involved in this cell-to-cell trafficking process.
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Affiliation(s)
- William J Lucas
- Section of Plant Biology, College of Biological Sciences, University of California, One Shields Ave., Davis, CA 95616, USA.
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46
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Bayne EH, Rakitina DV, Morozov SY, Baulcombe DC. Cell-to-cell movement of potato potexvirus X is dependent on suppression of RNA silencing. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2005; 44:471-82. [PMID: 16236156 DOI: 10.1111/j.1365-313x.2005.02539.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
RNA silencing in transgenic and virus-infected plants involves a mobile silencing signal that can move cell-to-cell and systemically through the plant. It is thought that this signal can influence long-distance movement of viruses because protein suppressors of silencing encoded in viral genomes are required for long-distance virus movement. However, until now, it was not known whether the mobile signal could also influence short-range virus movement between cells. Here, through random mutation analysis of the Potato Potexvirus X (PVX) silencing suppressor P25, we provide evidence that it does. All mutants that were defective for silencing suppression were also non-functional in viral cell-to-cell movement. However, we identified mutant P25 proteins that were functional as silencing suppressors but not as movement proteins and we conclude that suppression of silencing is not sufficient to allow virus movement between cells: there must be a second P25 function that is independent of silencing but also required for cell-to-cell movement. Consistent with this hypothesis, we identified two classes of suppressor-inactive P25 mutants. One class of these mutants is proposed to be functional for the accessory function because their failure to support PVX movement could be complemented by heterologous suppressors of silencing. The second class of P25 mutants is considered defective for both the suppressor and second functions because the heterologous silencing suppressors did not restore virus movement. It is possible, based on analyses of short interfering RNA accumulation, that P25 suppresses silencing by interfering with either assembly or function of the effector complexes of RNA silencing.
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Affiliation(s)
- Elizabeth H Bayne
- The Sainsbury Laboratory, John Innes Centre, Colney Lane, Norwich NR4 7UH, UK
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47
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Hammond J, Reinsel MD, Maroon-Lango CJ. Identification and full sequence of an isolate of Alternanthera mosaic potexvirus infecting Phlox stolonifera. Arch Virol 2005; 151:477-93. [PMID: 16211329 DOI: 10.1007/s00705-005-0646-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2005] [Accepted: 08/23/2005] [Indexed: 10/25/2022]
Abstract
A potexvirus was isolated from creeping phlox (Phlox stolonifera) plants from a commercial nursery in Pennsylvania. The virus was serologically related to clover yellow mosaic virus, plantain virus X, potato virus X, and potato aucuba mosaic virus, and was most closely related to papaya mosaic virus (PapMV). The sequence of a PCR fragment obtained with potexvirus group-specific primers was distinct from that of PapMV; the coat protein (CP) gene and 3' untranslated region (UTR) were closely related to Alternanthera mosaic virus (AltMV), previously reported only from Australia. The host range was similar to that of the Australian isolate (AltMV-Au), and the phlox isolate reacted strongly with antiserum to AltMV-Au. The full sequence of the phlox isolate was more closely related to PapMV throughout the genome than to any potexvirus other than AltMV-Au, for which only the CP and 3'UTR sequences are available. The phlox isolate was therefore named AltMV-PA (for Pennsylvania), and the full 6607 nt sequence is presented(1). Additional AltMV isolates from creeping phlox (AltMV-BR and AltMV-SP) and trailing portulaca (Portulaca grandiflora; AltMV-Po) were also isolated, suggesting that AltMV may be widespread, and may have been mis-diagnosed in the past as PapMV. AltMV has the potential to spread to other ornamental crops.
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Affiliation(s)
- J Hammond
- U.S. Department of Agriculture, Agricultural Research Service, U.S. National Arboretum, Floral and Nursery Plants Research Unit, Beltsville, Maryland 20705, USA.
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48
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Schepetilnikov MV, Manske U, Solovyev AG, Zamyatnin AA, Schiemann J, Morozov SY. The hydrophobic segment of Potato virus X TGBp3 is a major determinant of the protein intracellular trafficking. J Gen Virol 2005; 86:2379-2391. [PMID: 16033986 DOI: 10.1099/vir.0.80865-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Potato virus X (PVX) encodes three movement proteins, TGBp1, TGBp2 and TGBp3. The 8 kDa TGBp3 is a membrane-embedded protein that has an N-terminal hydrophobic sequence segment and a hydrophilic C terminus. TGBp3 mutants with deletions in the C-terminal hydrophilic region retain the ability to be targeted to cell peripheral structures and to support limited PVX cell-to-cell movement, suggesting that the basic TGBp3 functions are associated with its N-terminal transmembrane region. Fusion of green fluorescent protein to the TGBp3 N terminus abrogates protein activities in intracellular trafficking and virus movement. The intracellular transport of TGBp3 from sites of its synthesis in the rough endoplasmic reticulum (ER) to ER-derived peripheral bodies involves a non-conventional COPII-independent pathway. However, integrity of the C-terminal hydrophilic sequence is required for entrance to this non-canonical route.
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Affiliation(s)
- M V Schepetilnikov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | - U Manske
- Institute of Plant Virology, Microbiology and Biosafety, Federal Biological Research Centre for Agriculture and Forestry, Messeweg 11/12, D-38104 Braunschweig, Germany
| | - A G Solovyev
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
| | - A A Zamyatnin
- Department of Plant Biology and Forest Genetics, Swedish University of Agricultural Sciences (SLU), PO Box 7080, S-750 07 Uppsala, Sweden
- Natural Sciences Center of A. M. Prokhorov, General Physics Institute, Russian Academy of Sciences, Bld L-2, 38 Vavilov Str., Moscow 119991, Russia
| | - J Schiemann
- Institute of Plant Virology, Microbiology and Biosafety, Federal Biological Research Centre for Agriculture and Forestry, Messeweg 11/12, D-38104 Braunschweig, Germany
| | - S Yu Morozov
- A. N. Belozersky Institute of Physico-Chemical Biology, Moscow State University, Moscow 119899, Russia
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Nelson RS, Citovsky V. Plant viruses. Invaders of cells and pirates of cellular pathways. PLANT PHYSIOLOGY 2005; 138:1809-14. [PMID: 16172093 PMCID: PMC1183372 DOI: 10.1104/pp.104.900167] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
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50
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Verchot-Lubicz J. A new cell-to-cell transport model for Potexviruses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2005; 18:283-90. [PMID: 15828680 DOI: 10.1094/mpmi-18-0283] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
In the last five years, we have gained significant insight into the role of the Potexvirus proteins in virus movement and RNA silencing. Potexviruses require three movement proteins, named triple gene block (TGB)p1, TGBp2, and TGBp3, and the viral coat protein (CP) to facilitate viral cell-to-cell and vascular transport. TGBp1 is a multifunctional protein that has RNA helicase activity, promotes translation of viral RNAs, increases plasmodesmal size exclusion limits, and suppresses RNA silencing. TGBp2 and TGBp3 are membrane-binding proteins. CP is required for genome encapsidation and forms ribonucleoprotein complexes along with TGBp1 and viral RNA. This review considers the functions of the TGB proteins, how they interact with each other and CP, and how silencing suppression might be linked to viral transport. A new model of the mechanism for Potexvirus transport is proposed.
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Affiliation(s)
- Jeanmarie Verchot-Lubicz
- Oklahoma State University, Department of Entomology and Plant Pathology, Stillwater, OK 74078, USA.
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