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Kumar R, Dasgupta I. Geminiviral C4/AC4 proteins: An emerging component of the viral arsenal against plant defence. Virology 2023; 579:156-168. [PMID: 36693289 DOI: 10.1016/j.virol.2023.01.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Revised: 12/26/2022] [Accepted: 01/08/2023] [Indexed: 01/12/2023]
Abstract
Virus infection triggers a plethora of defence reactions in plants to incapacitate the intruder. Viruses, in turn, have added additional functions to their genes so that they acquire capabilities to neutralize the above defence reactions. In plant-infecting viruses, the family Geminiviridae comprises members, majority of whom encode 6-8 genes in their small single-stranded DNA genomes. Of the above genes, one which shows the most variability in its amino acid sequence is the C4/AC4. Recent studies have uncovered evidence, which point towards a wide repertoire of functions performed by C4/AC4 revealing its role as a major player in suppressing plant defence. This review summarizes the various plant defence mechanisms against viruses and highlights how C4/AC4 has evolved to counter most of them.
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Affiliation(s)
- Rohit Kumar
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India
| | - Indranil Dasgupta
- Department of Plant Molecular Biology, University of Delhi South Campus, Benito Juarez Road, New Delhi, 110021, India.
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2
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Zhao S, Gong P, Ren Y, Liu H, Li H, Li F, Zhou X. The novel C5 protein from tomato yellow leaf curl virus is a virulence factor and suppressor of gene silencing. STRESS BIOLOGY 2022; 2:19. [PMID: 37676365 PMCID: PMC10442036 DOI: 10.1007/s44154-022-00044-3] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 03/07/2022] [Indexed: 09/08/2023]
Abstract
Tomato yellow leaf curl virus (TYLCV) is known to encode 6 canonical viral proteins. Our recent study revealed that TYLCV also encodes some additional small proteins with potential virulence functions. The fifth ORF of TYLCV in the complementary sense, which we name C5, is evolutionarily conserved, but little is known about its expression and function during viral infection. Here, we confirmed the expression of the TYLCV C5 by analyzing the promoter activity of its upstream sequences and by detecting the C5 protein in infected cells by using a specific custom-made antibody. Ectopic expression of C5 using a potato virus X (PVX) vector resulted in severe mosaic symptoms and higher virus accumulation levels followed by a burst of reactive oxygen species (ROS) in Nicotiana benthamiana plants. C5 was able to effectively suppress local and systemic post-transcriptional gene silencing (PTGS) induced by single-stranded GFP but not double-stranded GFP, and reversed the transcriptional gene silencing (TGS) of GFP. Furthermore, the mutation of C5 in TYLCV inhibited viral replication and the development of disease symptoms in infected plants. Transgenic overexpression of C5 could complement the virulence of a TYLCV infectious clone encoding a dysfunctional C5. Collectively, this study reveals that TYLCV C5 is a pathogenicity determinant and RNA silencing suppressor, hence expanding our knowledge of the functional repertoire of the TYLCV proteome.
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Affiliation(s)
- Siwen Zhao
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Pan Gong
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Yanxiang Ren
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Hui Liu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Zhejiang, 310058, Hangzhou, China
| | - Hao Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Fangfang Li
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
| | - Xueping Zhou
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Zhejiang, 310058, Hangzhou, China.
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Zhai Y, Roy A, Peng H, Mullendore DL, Kaur G, Mandal B, Mukherjee SK, Pappu HR. Identification and Functional Analysis of Four RNA Silencing Suppressors in Begomovirus Croton Yellow Vein Mosaic Virus. FRONTIERS IN PLANT SCIENCE 2022; 12:768800. [PMID: 35069624 PMCID: PMC8777275 DOI: 10.3389/fpls.2021.768800] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Accepted: 11/30/2021] [Indexed: 06/01/2023]
Abstract
Croton yellow vein mosaic virus (CYVMV), a species in the genus Begomovirus, is a prolific monopartite begomovirus in the Indian sub-continent. CYVMV infects multiple crop plants to cause leaf curl disease. Plants have developed host RNA silencing mechanisms to defend the threat of viruses, including CYVMV. We characterized four RNA silencing suppressors, namely, V2, C2, and C4 encoded by CYVMV and betasatellite-encoded C1 protein (βC1) encoded by the cognate betasatellite, croton yellow vein betasatellite (CroYVMB). Their silencing suppressor functions were verified by the ability of restoring the β-glucuronidase (GUS) activity suppressed by RNA silencing. We showed here for the first time that V2 was capable of self-interacting, as well as interacting with the V1 protein, and could be translocalized to the plasmodesmata in the presence of CYVMV. The knockout of either V2 or V1 impaired the intercellular mobility of CYVMV, indicating their novel coordinated roles in the cell-to-cell movement of the virus. As pathogenicity determinants, each of V2, C2, and C4 could induce typical leaf curl symptoms in Nicotiana benthamiana plants even under transient expression. Interestingly, the transcripts and proteins of all four suppressors could be detected in the systemically infected leaves with no correlation to symptom induction. Overall, our work identifies four silencing suppressors encoded by CYVMV and its cognate betasatellite and reveals their subcellular localizations, interaction behavior, and roles in symptom induction and intercellular virus movement.
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Affiliation(s)
- Ying Zhai
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
| | - Anirban Roy
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Hao Peng
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
| | - Daniel L. Mullendore
- Franceschi Microscopy and Imaging Center, Washington State University, Pullman, WA, United States
| | - Gurpreet Kaur
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Bikash Mandal
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Sunil Kumar Mukherjee
- Advanced Center for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India
| | - Hanu R. Pappu
- Department of Plant Pathology, Washington State University, Pullman, WA, United States
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Positive selection and intrinsic disorder are associated with multifunctional C4(AC4) proteins and geminivirus diversification. Sci Rep 2021; 11:11150. [PMID: 34045539 PMCID: PMC8160170 DOI: 10.1038/s41598-021-90557-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 05/13/2021] [Indexed: 02/06/2023] Open
Abstract
Viruses within the Geminiviridae family cause extensive agricultural losses. Members of four genera of geminiviruses contain a C4 gene (AC4 in geminiviruses with bipartite genomes). C4(AC4) genes are entirely overprinted on the C1(AC1) genes, which encode the replication-associated proteins. The C4(AC4) proteins exhibit diverse functions that may be important for geminivirus diversification. In this study, the influence of natural selection on the evolutionary diversity of 211 C4(AC4) genes relative to the C1(AC1) sequences they overlap was determined from isolates of the Begomovirus and Curtovirus genera. The ratio of nonsynonymous (dN) to synonymous (dS) nucleotide substitutions indicated that C4(AC4) genes are under positive selection, while the overlapped C1(AC1) sequences are under purifying selection. Ninety-one of 200 Begomovirus C4(AC4) genes encode elongated proteins with the extended regions being under neutral selection. C4(AC4) genes from begomoviruses isolated from tomato from native versus exotic regions were under similar levels of positive selection. Analysis of protein structure suggests that C4(AC4) proteins are entirely intrinsically disordered. Our data suggest that non-synonymous mutations and mutations that increase the length of C4(AC4) drive protein diversity that is intrinsically disordered, which could explain C4/AC4 functional variation and contribute to both geminivirus diversification and host jumping.
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Loriato VAP, Martins LGC, Euclydes NC, Reis PAB, Duarte CEM, Fontes EPB. Engineering resistance against geminiviruses: A review of suppressed natural defenses and the use of RNAi and the CRISPR/Cas system. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2020; 292:110410. [PMID: 32005374 DOI: 10.1016/j.plantsci.2020.110410] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 11/22/2019] [Accepted: 01/07/2020] [Indexed: 05/21/2023]
Abstract
The Geminiviridae family is one of the most successful and largest families of plant viruses that infect a large variety of important dicotyledonous and monocotyledonous crops and cause significant yield losses worldwide. This broad spectrum of host range is only possible because geminiviruses have evolved sophisticated strategies to overcome the arsenal of antiviral defenses in such diverse plant species. In addition, geminiviruses evolve rapidly through recombination and pseudo-recombination to naturally create a great diversity of virus species with divergent genome sequences giving the virus an advantage over the host recognition system. Therefore, it is not surprising that efficient molecular strategies to combat geminivirus infection under open field conditions have not been fully addressed. In this review, we present the anti-geminiviral arsenal of plant defenses, the evolved virulence strategies of geminiviruses to overcome these plant defenses and the most recent strategies that have been engineered for transgenic resistance. Although, the in vitro reactivation of suppressed natural defenses as well as the use of RNAi and CRISPR/Cas systems hold the potential for achieving broad-range resistance and/or immunity, potential drawbacks have been associated with each case.
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Affiliation(s)
- Virgílio A P Loriato
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil; Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Laura G C Martins
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Nívea C Euclydes
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Pedro A B Reis
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil; Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Christiane E M Duarte
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil; Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil
| | - Elizabeth P B Fontes
- National Institute of Science and Technology in Plant-Pest Interactions, Bioagro, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil; Departament of Biochemistry and Molecular Biology, Universidade Federal de Viçosa, Viçosa, Minas Gerais, 36570-000, Brazil.
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Mubin M, Ijaz S, Nahid N, Hassan M, Younus A, Qazi J, Nawaz-Ul-Rehman MS. Journey of begomovirus betasatellite molecules: from satellites to indispensable partners. Virus Genes 2019; 56:16-26. [PMID: 31773493 DOI: 10.1007/s11262-019-01716-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Accepted: 11/17/2019] [Indexed: 12/21/2022]
Abstract
Betasatellites are a group of circular, single-stranded DNA molecules that are frequently found to be associated with monopartite begomoviruses of the family Geminiviridae. Betasatellites require their helper viruses for replication, movement, and encapsidation and they are often essential for induction of typical disease symptoms. The βC1 protein encoded by betasatellites is multifunctional that participates in diverse cellular events. It interferes with several cellular processes like normal development, chloroplasts, and innate immune system of plants. Recent research has indicated βC1 protein interaction with cellular proteins and its involvement in modulation of the host's cell cycle and symptom determination. This article focuses on the functional mechanisms of βC1 and its interactions with other viral and host proteins.
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Affiliation(s)
- Muhammad Mubin
- Virology Lab, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | - Sehrish Ijaz
- Virology Lab, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | - Nazia Nahid
- Department of Bioinformatics and Biotechnology, GC University Faisalabad, Faisalabad, Pakistan
| | - Muhammad Hassan
- Virology Lab, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | - Ayesha Younus
- Laser Matter Interaction and Nano-sciences Lab, Department of Physics, University of Agriculture Faisalabad, Faisalabad, Pakistan
| | - Javaria Qazi
- Department of Biotechnology, Quaid e Azam University, Islamabad, Pakistan
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Kulshreshtha A, Kumar Y, Roshan P, Bhattacharjee B, Mukherjee SK, Hallan V. AC4 protein of tomato leaf curl Palampur virus is an RNA silencing suppressor and a pathogenicity determinant. Microb Pathog 2019; 135:103636. [PMID: 31377236 DOI: 10.1016/j.micpath.2019.103636] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 07/17/2019] [Indexed: 01/08/2023]
Abstract
Plants deploy RNA silencing as a natural defence against invading viruses involving sequence-specific degradation of the viral RNAs. As a counter-defence strategy, viruses encode suppressor proteins that simultaneously target different steps of the silencing machinery. Tomato leaf curl Palampur virus (ToLCPalV) is a bipartite begomovirus in Geminiviridae family. It is responsible for significant reduction in the crop yield and quality. DNA-A of the virus encodes for six proteins whereas DNA-B codes for two proteins. In this study, all viral genes were screened for their role in suppression of green fluorescent protein (GFP) silencing in Nicotiana tabacum cv. Xanthi, employing agrobacterium based co-infiltration assay. The assay identified AC4 as a potential suppressor of RNA silencing. In addition, AC4 expression also suppressed virus-induced gene silencing (VIGS) of the phytoene desaturase (PDS) gene in N. benthamiana. Potato virus X (PVX) mediated transient expression of the AC4 in N. benthamiana showed enhanced symptoms that include downward leaf curling, leaf puckering and tissue necrosis. Further, N. benthamiana lines stably expressing AC4 showed severe developmental abnormalities. Mutational analysis suggested that glycine at 2nd position is essential for AC4 pathogenicity. Collectively, these findings demonstrate the role of ToLCPalV AC4 in viral pathogenesis, disease establishment and suppression of gene silencing.
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Affiliation(s)
- Aditya Kulshreshtha
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India; Plant Virus Lab, Biotechnology Division, CSIR-IHBT, Palampur, Himachal Pradesh, 176061, India
| | - Yogesh Kumar
- Department of Biotechnology, DAV University, Jalandhar, 144012, Punjab, India
| | - Poonam Roshan
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India; Plant Virus Lab, Biotechnology Division, CSIR-IHBT, Palampur, Himachal Pradesh, 176061, India
| | - Bipasha Bhattacharjee
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India; Plant Virus Lab, Biotechnology Division, CSIR-IHBT, Palampur, Himachal Pradesh, 176061, India
| | - Sunil Kumar Mukherjee
- Division of Plant Pathology, India Agricultural Research Institute, Pusa, New Delhi, 110012, India
| | - Vipin Hallan
- Academy of Scientific and Innovative Research (AcSIR), CSIR-Institute of Himalayan Bioresource Technology, Palampur, Himachal Pradesh, 176061, India; Plant Virus Lab, Biotechnology Division, CSIR-IHBT, Palampur, Himachal Pradesh, 176061, India.
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8
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Gnanasekaran P, KishoreKumar R, Bhattacharyya D, Vinoth Kumar R, Chakraborty S. Multifaceted role of geminivirus associated betasatellite in pathogenesis. MOLECULAR PLANT PATHOLOGY 2019; 20:1019-1033. [PMID: 31210029 PMCID: PMC6589721 DOI: 10.1111/mpp.12800] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Begomoviruses have emerged as a group of plant pathogens that cause devastating diseases in a wide range of crops in tropical and subtropical regions of the world. Betasatellites, the circular single-stranded DNA molecules with the size of almost half of that of the associated helper begomoviruses, are often essential for the production of typical disease symptoms in several virus-host systems. Association of betasatellites with begomoviruses results in more severe symptoms in the plants and affects the yield of numerous crops leading to huge agroeconomic losses. βC1, the only protein encoded by betasatellites, plays a multifaceted role in the successful establishment of infection. This protein counteracts the innate defence mechanisms of the host, like RNA silencing, ubiquitin-proteasome system and defence responsive hormones. In the last two decades, the molecular aspect of betasatellite pathogenesis has attracted much attention from the researchers worldwide, and reports have shown that βC1 protein aggravates the helper begomovirus disease complex by modulating specific host factors. This review discusses the molecular aspects of the pathogenesis of betasatellites, including various βC1-host factor interactions and their effects on the suppression of defence responses of the plants.
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Affiliation(s)
- Prabu Gnanasekaran
- Molecular Virology Laboratory, School of Life SciencesJawaharlal Nehru UniversityNew Delhi110 067India
| | - Reddy KishoreKumar
- Molecular Virology Laboratory, School of Life SciencesJawaharlal Nehru UniversityNew Delhi110 067India
| | - Dhriti Bhattacharyya
- Molecular Virology Laboratory, School of Life SciencesJawaharlal Nehru UniversityNew Delhi110 067India
| | - R. Vinoth Kumar
- Molecular Virology Laboratory, School of Life SciencesJawaharlal Nehru UniversityNew Delhi110 067India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life SciencesJawaharlal Nehru UniversityNew Delhi110 067India
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Rishishwar R, Dasgupta I. Suppressors of RNA silencing encoded by geminiviruses and associated DNA satellites. Virusdisease 2019; 30:58-65. [PMID: 31143832 PMCID: PMC6517462 DOI: 10.1007/s13337-018-0418-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 01/05/2018] [Indexed: 12/31/2022] Open
Abstract
In plants, RNA silencing provides a major line of defence against viruses. This antiviral immunity involves production of virus-derived small interfering RNAs (vsiRNAs) and results in specific silencing of viruses by vsiRNAs-guided effector complexes. As a counterattack against RNA silencing, many plant viruses encode suppressors of RNA silencing called viral suppressors of RNA silencing (VSRs), which interfere with the silencing pathway by various mechanisms. This review describes various methods that are being used to characterize viral proteins for suppressor function, VSRs found in geminiviruses and associated DNA satellites and their mechanisms of action.
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Affiliation(s)
- Rashmi Rishishwar
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021 India
| | - Indranil Dasgupta
- Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, 110021 India
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10
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Lu QY, Yang L, Huang J, Zheng L, Sun X. Identification and subcellular location of an RNA silencing suppressor encoded by mulberry crinkle leaf virus. Virology 2019; 526:45-51. [PMID: 30342301 DOI: 10.1016/j.virol.2018.10.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/04/2018] [Accepted: 10/04/2018] [Indexed: 11/28/2022]
Abstract
Mulberry crinkle leaf virus (MCLV) is a novel geminivirus recently identified from the woody plant mulberry (Morus alba L.). Little is known about the functions of the proteins encoded by the MCLV genome. Here, all the MCLV-encoded proteins were examined for the ability to suppress gene silencing by an agroinfiltration assay in combination with northern blot analysis of green fluorescent protein (GFP) mRNA and western blot analysis. Of the six proteins, only one protein, V3, which has been predicted to play a role in viral movement, was found to suppress the gene silencing induced by a sense GFP gene in Nicotiana benthamiana 16c. The minimal amino acid sequence of V3 that maintains suppressor activity was also determined by constructing truncated mutants lacking different lengths of the amino acid sequences at the N- or C-terminus of the V3 protein. The results showed that the 94 N-terminal amino acid residues of V3 are sufficient to maintain V3 suppressor activity. In addition, the subcellular location of the V3 protein was investigated by confocal laser scanning microscopy after the expression of a V3-RFP fused protein in leaf epidermal cells of N. benthamiana. The results indicated that the V3 protein localized not only to the cytoplasm but also to the nucleus of N. benthamiana, implying that V3 can shuttle between the nucleus and the cytoplasm. Deletion mutant analysis indicated that a putative nuclear localization signal (NLS) between aa 118-134 might be responsible for the nuclear distribution of the V3 protein. Given the importance of RNA silencing in plant-virus interactions, the identification of a silencing suppressor of MCLV should be valuable in understanding the pathogenicity and molecular biology of this virus.
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Affiliation(s)
- Quan-You Lu
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China; Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China.
| | - Lei Yang
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China; Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China
| | - Jinshan Huang
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China; Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China
| | - Luping Zheng
- College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian, China
| | - Xin Sun
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China; Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, College of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang 212018, Jiangsu, China
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11
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Basu S, Kumar Kushwaha N, Kumar Singh A, Pankaj Sahu P, Vinoth Kumar R, Chakraborty S. Dynamics of a geminivirus-encoded pre-coat protein and host RNA-dependent RNA polymerase 1 in regulating symptom recovery in tobacco. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2085-2102. [PMID: 29432546 PMCID: PMC6019014 DOI: 10.1093/jxb/ery043] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 01/24/2018] [Indexed: 05/21/2023]
Abstract
RNA silencing is an integral part of the cellular defense mechanisms in plants that act against virus infection. However, the specific role of RNA silencing and the interplay between host and virus components during recovery from geminivirus infection remains unknown. Hence, in this study we aimed to examine the mechanism behind the host-specific recovery of Nicotiana tabacum infected with Tomato leaf curl Gujarat virus (ToLCGV). Unlike Tomato leaf curl New Delhi virus (ToLCNDV), ToLCGV infection resulted in symptom remission in N. tabacum, and we found that this was mainly due to cross-talk between the pre-coat protein (encoded by the AV2 ORF) of the virus and the host RNA-silencing component RNA-dependent RNA polymerase 1 (encoded by NtRDR1) of N. tabacum. Moreover, apart from the AV2 mutant, other mutants of ToLCNDV developed severe symptoms on a transgenic NtRDR1-overexpression line of N. benthamiana. In contrast, inoculation with ToLCGV resulted in symptom remission, which was due to enhanced methylation of the ToLCGV promoter. Our study reveals a novel 'arms race' in which the pre-coat protein of ToLCNDV selectively blocks the recovery process through inhibiting host-specific RDR1-mediated antiviral silencing in tobacco.
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Affiliation(s)
- Saumik Basu
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Nirbhay Kumar Kushwaha
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Ashish Kumar Singh
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Pranav Pankaj Sahu
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - R Vinoth Kumar
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
| | - Supriya Chakraborty
- Molecular Virology Laboratory, School of Life Sciences, Jawaharlal Nehru University, New Delhi, India
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12
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Ramesh SV, Sahu PP, Prasad M, Praveen S, Pappu HR. Geminiviruses and Plant Hosts: A Closer Examination of the Molecular Arms Race. Viruses 2017; 9:E256. [PMID: 28914771 PMCID: PMC5618022 DOI: 10.3390/v9090256] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 09/02/2017] [Accepted: 09/06/2017] [Indexed: 11/24/2022] Open
Abstract
Geminiviruses are plant-infecting viruses characterized by a single-stranded DNA (ssDNA) genome. Geminivirus-derived proteins are multifunctional and effective regulators in modulating the host cellular processes resulting in successful infection. Virus-host interactions result in changes in host gene expression patterns, reprogram plant signaling controls, disrupt central cellular metabolic pathways, impair plant's defense system, and effectively evade RNA silencing response leading to host susceptibility. This review summarizes what is known about the cellular processes in the continuing tug of war between geminiviruses and their plant hosts at the molecular level. In addition, implications for engineered resistance to geminivirus infection in the context of a greater understanding of the molecular processes are also discussed. Finally, the prospect of employing geminivirus-based vectors in plant genome engineering and the emergence of powerful genome editing tools to confer geminivirus resistance are highlighted to complete the perspective on geminivirus-plant molecular interactions.
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Affiliation(s)
- Shunmugiah V Ramesh
- ICAR-Indian Institute of Soybean Research, Indian Council of Agricultural Research, Indore 452001, India.
- Department of Plant Pathology, Washington State University, Pullman, WA 99163, USA.
| | - Pranav P Sahu
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi110067, India.
| | - Manoj Prasad
- National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi110067, India.
| | - Shelly Praveen
- Division of Plant Pathology, Advanced Centre for Plant Virology, ICAR-Indian Agricultural Research Institute (IARI), New Delhi 110012, India.
| | - Hanu R Pappu
- Department of Plant Pathology, Washington State University, Pullman, WA 99163, USA.
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13
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Shen Q, Hu T, Bao M, Cao L, Zhang H, Song F, Xie Q, Zhou X. Tobacco RING E3 Ligase NtRFP1 Mediates Ubiquitination and Proteasomal Degradation of a Geminivirus-Encoded βC1. MOLECULAR PLANT 2016; 9:911-25. [PMID: 27018391 DOI: 10.1016/j.molp.2016.03.008] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Revised: 02/17/2016] [Accepted: 03/03/2016] [Indexed: 05/19/2023]
Abstract
The βC1 protein encoded by the Tomato yellow leaf curl China virus-associated betasatellite functions as a pathogenicity determinant. To better understand the molecular basis whereby βC1 functions in pathogenicity, a yeast two-hybrid screen of a tobacco cDNA library was carried out using βC1 as the bait. The screen revealed that βC1 interacts with a tobacco RING-finger protein designated NtRFP1, which was further confirmed by the bimolecular fluorescence complementation and co-immunoprecipitation assays in Nicotiana benthamiana cells. Expression of NtRFP1 was induced by βC1, and in vitro ubiquitination assays showed that NtRFP1 is a functional E3 ubiquitin ligase that mediates βC1 ubiquitination. In addition, βC1 was shown to be ubiquitinated in vivo and degraded by the plant 26S proteasome. After viral infection, plants overexpressing NtRFP1 developed attenuated symptoms, whereas plants with silenced expression of NtRFP1 showed severe symptoms. Other lines of evidence showed that NtRFP1 attenuates βC1-induced symptoms through promoting its degradation by the 26S proteasome. Taken together, our results suggest that tobacco RING E3 ligase NtRFP1 attenuates disease symptoms by interacting with βC1 to mediate its ubiquitination and degradation via the ubiquitin/26S proteasome system.
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Affiliation(s)
- Qingtang Shen
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Tao Hu
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Min Bao
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Linge Cao
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Huawei Zhang
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Fengmin Song
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Chinese Academy of Sciences, Beijing 100101, China
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China; State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing 100193, China.
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14
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Jia Q, Liu N, Xie K, Dai Y, Han S, Zhao X, Qian L, Wang Y, Zhao J, Gorovits R, Xie D, Hong Y, Liu Y. CLCuMuB βC1 Subverts Ubiquitination by Interacting with NbSKP1s to Enhance Geminivirus Infection in Nicotiana benthamiana. PLoS Pathog 2016; 12:e1005668. [PMID: 27315204 PMCID: PMC4912122 DOI: 10.1371/journal.ppat.1005668] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 05/10/2016] [Indexed: 11/21/2022] Open
Abstract
Viruses interfere with and usurp host machinery and circumvent defense responses to create a suitable cellular environment for successful infection. This is usually achieved through interactions between viral proteins and host factors. Geminiviruses are a group of plant-infecting DNA viruses, of which some contain a betasatellite, known as DNAβ. Here, we report that Cotton leaf curl Multan virus (CLCuMuV) uses its sole satellite-encoded protein βC1 to regulate the plant ubiquitination pathway for effective infection. We found that CLCuMu betasatellite (CLCuMuB) βC1 interacts with NbSKP1, and interrupts the interaction of NbSKP1s with NbCUL1. Silencing of either NbSKP1s or NbCUL1 enhances the accumulation of CLCuMuV genomic DNA and results in severe disease symptoms in plants. βC1 impairs the integrity of SCFCOI1 and the stabilization of GAI, a substrate of the SCFSYL1 to hinder responses to jasmonates (JA) and gibberellins (GA). Moreover, JA treatment reduces viral accumulation and symptoms. These results suggest that CLCuMuB βC1 inhibits the ubiquitination function of SCF E3 ligases through interacting with NbSKP1s to enhance CLCuMuV infection and symptom induction in plants.
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Affiliation(s)
- Qi Jia
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Na Liu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Ke Xie
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yanwan Dai
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
- College of Biological Sciences, China Agricultural University, Beijing, China
| | - Shaojie Han
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Xijuan Zhao
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Lichao Qian
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yunjing Wang
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Jinping Zhao
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
- Institute of Virology and Biotechnology, Zhejiang Academy of Agricultural Sciences, Hangzhou, China
| | - Rena Gorovits
- Institute of Plant Sciences and Genetics in Agriculture, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Daoxin Xie
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
| | - Yiguo Hong
- Research Centre for Plant RNA Signaling, College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, China
| | - Yule Liu
- MOE Key Laboratory of Bioinformatics, Center for Plant Biology, School of Life Sciences, Tsinghua University, Beijing, China
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15
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Zhang J, Dang M, Huang Q, Qian Y. Determinants of Disease Phenotype Differences Caused by Closely-Related Isolates of Begomovirus Betasatellites Inoculated with the Same Species of Helper Virus. Viruses 2015; 7:4945-59. [PMID: 26389936 PMCID: PMC4584297 DOI: 10.3390/v7092853] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 08/25/2015] [Accepted: 08/28/2015] [Indexed: 01/03/2023] Open
Abstract
Tomato yellow leaf curl China virus (TYLCCNV) is a monopartite begomovirus associated with different betasatellites. In this study, we investigate two different isolates of Tomato yellow leaf curl China betasatellite (TYLCCNB) to determine what features of the viral genome are required for induction of characteristic phenotypic differences between closely-related betasatellite. When co-agroinoculated with TYLCCNV into Nicotiana spp. and tomato plants, TYLCCNB-Y25 induced only leaf curling on all hosts, while TYLCCNB-Y10 also induced enations, vein yellowing, and shoot distortions. Further assays showed that βC1 of TYLCCNB-Y25 differs from that of TYLCCNB-Y10 in symptom induction and transcriptional modulating. Hybrid satellites were constructed in which the βC1 gene or 200 nt partial promoter-like fragment upstream of the βC1 were exchanged. Infectivity assays showed that a TYLCCNB-Y25 hybrid with the intact TYLCCNB-Y10 βC1 gene was able to induce vein yellowing, shoot distortions, and a reduced size and number of enations. A TYLCCNB-Y10 hybrid with the intact TYLCCNB-Y25 βC1 gene produced only leaf curling. In contrast, the TYLCCNB-Y25 and TYLCCNB-Y10 hybrids with swapped partial promoter-like regions had little effect on the phenotypes induced by wild-type betasatellites. Further experiments showed that the TYLCCNB-Y25 hybrid carrying the C-terminal region of TYLCCNB-Y10 βC1 induced TYLCCNB-Y10-like symptoms. These findings indicate that the βC1 protein is the major symptom determinant and that the C-terminal region of βC1 plays an important role in symptom induction.
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Affiliation(s)
- Jie Zhang
- Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
- Institute of Plant Virology, Fujian Agriculture and Forestry University, Fuzhou 350002, China.
| | - Mingqing Dang
- Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Qingqing Huang
- Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Yajuan Qian
- Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
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16
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Csorba T, Kontra L, Burgyán J. viral silencing suppressors: Tools forged to fine-tune host-pathogen coexistence. Virology 2015; 479-480:85-103. [DOI: 10.1016/j.virol.2015.02.028] [Citation(s) in RCA: 368] [Impact Index Per Article: 40.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Revised: 01/31/2015] [Accepted: 02/16/2015] [Indexed: 12/27/2022]
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17
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Fahad S, Khan FA, Pandupuspitasari NS, Ahmed MM, Liao YC, Waheed MT, Sameeullah M, Darkhshan, Hussain S, Saud S, Hassan S, Jan A, Jan MT, Wu C, Chun MX, Huang J. Recent developments in therapeutic protein expression technologies in plants. Biotechnol Lett 2015; 37:265-79. [PMID: 25326175 PMCID: PMC7088338 DOI: 10.1007/s10529-014-1699-7] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2014] [Accepted: 10/06/2014] [Indexed: 12/17/2022]
Abstract
Infectious diseases and cancers are some of the commonest causes of deaths throughout the world. The previous two decades have witnessed a combined endeavor across various biological sciences to address this issue in novel ways. The advent of recombinant DNA technologies has provided the tools for producing recombinant proteins that can be used as therapeutic agents. A number of expression systems have been developed for the production of pharmaceutical products. Recently, advances have been made using plants as bioreactors to produce therapeutic proteins directed against infectious diseases and cancers. This review highlights the recent progress in therapeutic protein expression in plants (stable and transient), the factors affecting heterologous protein expression, vector systems and recent developments in existing technologies and steps towards the industrial production of plant-made vaccines, antibodies, and biopharmaceuticals.
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Affiliation(s)
- Shah Fahad
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Street, Hongshan District, Wuhan, 430070 Hubei China
| | - Faheem Ahmed Khan
- Molecular Biotechnology Laboratory for Triticeae Crops, Huazhong Agricultural University, Wuhan, China
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction, Huazhong Agricultural University, Wuhan, 430070 China
| | | | | | - Yu Cai Liao
- College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, China
| | | | - Muhammad Sameeullah
- Biotechnology Lab., Department of Biology, Faculty of Science and Arts, Abant Izzet Baysal University, Golkoy Campus, 14280 Bolu, Turkey
| | - Darkhshan
- Women Institute of Learning, Abbottabad, Pakistan
| | - Saddam Hussain
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Street, Hongshan District, Wuhan, 430070 Hubei China
| | - Shah Saud
- Department of Horticultural, Northeast Agricultural University, Harbin, 150030 China
| | - Shah Hassan
- Agriculture University, Peshawar, 25000 Pakistan
| | | | | | - Chao Wu
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Street, Hongshan District, Wuhan, 430070 Hubei China
| | - Ma Xiao Chun
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Street, Hongshan District, Wuhan, 430070 Hubei China
| | - Jianliang Huang
- National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, No. 1 Shizishan Street, Hongshan District, Wuhan, 430070 Hubei China
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18
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Sohrab SS, Azhar EI, Kamal MA, Bhattacharya PS, Rana D. Genetic variability of Cotton leaf curl betasatellite in Northern India. Saudi J Biol Sci 2014; 21:626-31. [PMID: 25473373 DOI: 10.1016/j.sjbs.2014.11.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 11/02/2014] [Accepted: 11/03/2014] [Indexed: 11/20/2022] Open
Abstract
Cotton is an important crop and its production is affected by various disease pathogens. Monopartite begomovirus associated betasatellites cause Cotton leaf curl disease (CLCuD) in Northern India. In order to access the occurrence and genetic variability of Cotton leaf curl betasatellites, an extensive field survey was conducted in states of Rajasthan, Punjab and Haryana. We selected the betasatellite sequence for analysis as they are reported as important for disease severity and sequence variability. Based on the field observations, the disease incidence ranged from 30% to 80% during the survey. Full genome and DNA β were amplified from various samples while no amplicon was obtained in some samples. The nucleotide sequence homology ranged from 90.0% to 98.7% with Cotton leaf curl virus (CLCuV), 55.2-55.5% with Bhendi yellow vein mosaic virus, 55.8% with Okra leaf curl virus and 51.70% with Tomato leaf curl virus isolates. The lowest similarity (47.8%) was found in CLCuV-Sudan isolate. Phylogenetic analysis showed that analyzed isolates formed a close cluster with various CLCuV isolates reported earlier. The analysis results show sequence variation in Cotton leaf curl betasatellite which could be the result of recombination. The results obtained by genome amplification and sequence variability indicate that some new variants are circulating and causing leaf curl disease in Rajasthan, Punjab and Haryana.
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Affiliation(s)
- Sayed Sartaj Sohrab
- Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Post Box No. 80216, Jeddah 21589, Saudi Arabia
| | - Esam I Azhar
- Special Infectious Agents Unit, King Fahd Medical Research Center, King Abdulaziz University, Post Box No. 80216, Jeddah 21589, Saudi Arabia
| | - Mohammad A Kamal
- King Fahd Medical Research Center, King Abdulaziz University, Post Box No. 80216, Jeddah 21589, Saudi Arabia
| | - P S Bhattacharya
- Division of Biotechnology, JK-AgriGenetics Ltd., Hyderabad, A.P., India
| | - D Rana
- Division of Biotechnology, JK-AgriGenetics Ltd., Hyderabad, A.P., India
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19
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Regional changes in the sequence of cotton leaf curl multan betasatellite. Viruses 2014; 6:2186-203. [PMID: 24859342 PMCID: PMC4036549 DOI: 10.3390/v6052186] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2014] [Revised: 05/02/2014] [Accepted: 05/12/2014] [Indexed: 11/23/2022] Open
Abstract
Cotton leaf curl disease (CLCuD) in Pakistan and northwestern India is caused by monopartite begomoviruses in association with an essential, disease-specific satellite, Cotton leaf curl Multan betasatellite (CLCuMB). Following a recent upsurge in CLCuD problems in Sindh province (southern Pakistan), sequences of clones of CLCuMB were obtained from Sindh and Punjab province (central Pakistan), where CLCuD has been a problem since the mid-1980s. The sequences were compared to all sequences of CLCuMB available in the databases. Analysis of the sequences shows extensive sequence variation in CLCuMB, most likely resulting from recombination. The range of sequence variants differ between Sindh, the Punjab and northwestern India. The possible significance of the findings with respect to movement of the CLCuD between the three regions is discussed. Additionally, the lack of sequence variation within the only coding sequence of CLCuMB suggests that the betasatellite is not involved in resistance breaking which became a problem after 2001 in the Punjab and subsequently also in northwestern India.
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20
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Li F, Huang C, Li Z, Zhou X. Suppression of RNA silencing by a plant DNA virus satellite requires a host calmodulin-like protein to repress RDR6 expression. PLoS Pathog 2014; 10:e1003921. [PMID: 24516387 PMCID: PMC3916407 DOI: 10.1371/journal.ppat.1003921] [Citation(s) in RCA: 139] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Accepted: 12/24/2013] [Indexed: 11/19/2022] Open
Abstract
In plants, RNA silencing plays a key role in antiviral defense. To counteract host defense, plant viruses encode viral suppressors of RNA silencing (VSRs) that target different effector molecules in the RNA silencing pathway. Evidence has shown that plants also encode endogenous suppressors of RNA silencing (ESRs) that function in proper regulation of RNA silencing. The possibility that these cellular proteins can be subverted by viruses to thwart host defense is intriguing but has not been fully explored. Here we report that the Nicotiana benthamiana calmodulin-like protein Nbrgs-CaM is required for the functions of the VSR βC1, the sole protein encoded by the DNA satellite associated with the geminivirus Tomato yellow leaf curl China virus (TYLCCNV). Nbrgs-CaM expression is up-regulated by the βC1. Transgenic plants over-expressing Nbrgs-CaM displayed developmental abnormities reminiscent of βC1-associated morphological alterations. Nbrgs-CaM suppressed RNA silencing in an Agrobacterium infiltration assay and, when over-expressed, blocked TYLCCNV-induced gene silencing. Genetic evidence showed that Nbrgs-CaM mediated the βC1 functions in silencing suppression and symptom modulation, and was required for efficient virus infection. Moreover, the tobacco and tomato orthologs of Nbrgs-CaM also possessed ESR activity, and were induced by betasatellite to promote virus infection in these Solanaceae hosts. We further demonstrated that βC1-induced Nbrgs-CaM suppressed the production of secondary siRNAs, likely through repressing RNA-DEPENDENT RNA POLYMERASE 6 (RDR6) expression. RDR6-deficient N. benthamiana plants were defective in antiviral response and were hypersensitive to TYLCCNV infection. More significantly, TYLCCNV could overcome host range restrictions to infect Arabidopsis thaliana when the plants carried a RDR6 mutation. These findings demonstrate a distinct mechanism of VSR for suppressing PTGS through usurpation of a host ESR, and highlight an essential role for RDR6 in RNA silencing defense response against geminivirus infection.
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Affiliation(s)
- Fangfang Li
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Changjun Huang
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Zhenghe Li
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
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21
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Association of an alphasatellite with tomato yellow leaf curl virus and ageratum yellow vein virus in Japan is suggestive of a recent introduction. Viruses 2014; 6:189-200. [PMID: 24424499 PMCID: PMC3917438 DOI: 10.3390/v6010189] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2013] [Revised: 12/04/2013] [Accepted: 12/17/2013] [Indexed: 11/22/2022] Open
Abstract
Samples were collected in 2011 from tomato plants exhibiting typical tomato leaf curl disease symptoms in the vicinity of Komae, Japan. PCR mediated amplification, cloning and sequencing of all begomovirus components from two plants from different fields showed the plants to be infected by Tomatoyellowleafcurlvirus (TYLCV) and Ageratumyellowveinvirus (AYVV). Both viruses have previously been shown to be present in Japan, although this is the first identification of AYVV on mainland Japan; the virus previously having been shown to be present on the Okinawa Islands. The plant harboring AYVV was also shown to contain the betasatellite Tomato leaf curl Java betasatellite (ToLCJaB), a satellite not previously shown to be present in Japan. No betasatellite was associated with the TYLCV infected tomato plants analyzed here, consistent with earlier findings for this virus in Japan. Surprisingly both plants were also found to harbor an alphasatellite; no alphasatellites having previously been reported from Japan. The alphasatellite associated with both viruses was shown to be Sida yellow vein China alphasatellite which has previously only been identified in the Yunnan Province of China and Nepal. The results suggest that further begomoviruses, and their associated satellites, are being introduced to Japan. The significance of these findings is discussed.
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22
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Khan AJ, Akhtar S, Al-Zaidi AM, Singh AK, Briddon RW. Genetic diversity and distribution of a distinct strain of Chili leaf curl virus and associated betasatellite infecting tomato and pepper in Oman. Virus Res 2013; 177:87-97. [PMID: 23911631 DOI: 10.1016/j.virusres.2013.07.018] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2013] [Revised: 07/12/2013] [Accepted: 07/20/2013] [Indexed: 11/28/2022]
Abstract
Tomato and pepper are widely grown in Oman for local consumption. A countrywide survey was conducted during 2010-2011 to collect samples and assess the diversity of begomoviruses associated with leaf curl disease of tomato and pepper. A virus previously only identified on the Indian subcontinent, chili leaf curl virus (ChLCV), was found associated with tomato and pepper diseases in all vegetable grown areas of Oman. Some of the infected plant samples were also found to contain a betasatellite. A total of 19 potentially full-length begomovirus and eight betasatellite clones were sequenced. The begomovirus clones showed >96% nucleotide sequence identity, showing them to represent a single species. Comparisons to sequences available in the databases showed the highest levels of nucleotide sequence identity (88.0-91.1%) to isolates of the "Pakistan" strain of ChLCV (ChLCV-PK), indicating the virus from Oman to be a distinct strain, for which the name Oman strain (ChLCV-OM) is proposed. An analysis for recombination showed ChLCV-OM likely to have originated by recombination between ChLCV-PK (the major parent), pepper leaf curl Lahore virus and a third strain of ChLCV. The betasatellite sequences obtained were shown to have high levels of identity to isolates of tomato leaf curl betasatellite (ToLCB) previous shown to be present in Oman. For the disease in tomato Koch's postulates were satisfied by Agrobacterium-mediated inoculation of virus and betasatellites clones. This showed the symptoms induced by the virus in the presence of the betasatellite to be enhanced, although viral DNA levels were not affected. ChLCV-OM is the fourth begomovirus identified in tomato in Oman and the first in Capsicum. The significance of these findings is discussed.
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Affiliation(s)
- Akhtar J Khan
- Department of Crop Sciences, College of Agricultural and Marine Sciences, Sultan Qaboos University, P.O. Box-34, Al-Khod 123, Oman.
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23
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Jyothsna P, Haq QMI, Singh P, Sumiya KV, Praveen S, Rawat R, Briddon RW, Malathi VG. Infection of tomato leaf curl New Delhi virus (ToLCNDV), a bipartite begomovirus with betasatellites, results in enhanced level of helper virus components and antagonistic interaction between DNA B and betasatellites. Appl Microbiol Biotechnol 2013; 97:5457-71. [PMID: 23306645 DOI: 10.1007/s00253-012-4685-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 12/20/2012] [Accepted: 12/22/2012] [Indexed: 11/24/2022]
Abstract
Tomato leaf curl New Delhi virus (ToLCNDV) (Geminiviridae) is an important pathogen that severely affects tomato production. An extensive survey was carried out during 2003-2010 to study the diversity of begomoviruses found in tomato, potato, and cucurbits that showed symptoms of leaf puckering, distortion, curling, vein clearing, and yellow mosaic in various fields in different regions of India. Ten begomovirus isolates were cloned from infected samples and identified as belonging to the species ToLCNDV. A total of 44 % of the samples showed association of betasatellites, with CLCuMuB and LuLDB being the most frequent. The ToLCNDV cloned component DNA A and DNA B were agroinoculated on Nicotiana benthamiana and tomato (Solanum lycopersicum) plants with or without betasatellites, CLCuMuB or LuLDB. The viral genome levels were then monitored by real-time polymerase chain reaction at different time points of disease development. Plants co-inoculated with betasatellites showed enhanced symptom severity in both N. benthamiana and tomato, as well as increases in helper viral DNA A and DNA B levels. The DNA B and betasatellites acted antagonistically to each other, so that the level of DNA B was 16-fold greater in the presence of betasatellites, while accumulation of betasatellites, CLCuMuB and LuLDB, were reduced by 60 % in the presence of DNA B. DNA B-mediated symptoms predominated in CLCuMuB-inoculated plants, whereas betasatellite-mediated leaf abnormalities were prominent in LuLDB-co-inoculated plants. Inoculation with the cloned components will be a good biotechnological tool in resistance breeding program.
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Affiliation(s)
- P Jyothsna
- Advanced Centre for Plant Virology, Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, India 110012
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24
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Shukla R, Dalal S, Malathi VG. Suppressors of RNA silencing encoded by tomato leaf curl betasatellites. J Biosci 2013; 38:45-51. [PMID: 23385812 DOI: 10.1007/s12038-012-9291-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Virus encoded RNA-silencing suppressors (RSSs) are the key components evolved by the viruses to counter RNA-silencing defense of plants. Whitefly-transmitted begomoviruses infecting tomato crop code for five different proteins, ORF AC4, ORF AC2 and ORF AV2 in DNA-A component, ORF BV1 in DNA-B and ORF beta C1 in satellite DNA beta which are predicted to function as silencing suppressors. In the present study suppressor function of ORF beta C1 of three betasatellites Tomato leaf curl Bangalore betasatellite ToLCBB-[IN:Hess:08], Cotton leaf curl Multan betasatellite CLCuMB-[IN:Sri:02] and Luffa leaf distortion betasatellite LuLDB-[IN:Lu:04] were examined. Agroinfiltration of GFP-silenced Nicotiana tabaccum cv. Xanthi with the cells expressing betaC1 protein resulted in reversal of silenced GFP expression. GFP-siRNA level was more than 50-fold lower compared to silenced plants in plants infiltrated with betaC1 gene from ToLCBB. However, in the case of 35S-beta C1 CLCuMB and 35S- beta C1 LuLDB construct, although GFP was expressed, siRNA level was not reduced, indicating that the step at which beta C1 interfere in RNA-silencing pathway is different.
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Affiliation(s)
- Richa Shukla
- Advanced Centre for Plant Virology, Div. of Plant Pathology, Indian Agricultural Research Institute, New Delhi 110 012
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Eini O, Dogra SC, Dry IB, Randles JW. Silencing suppressor activity of a begomovirus DNA β encoded protein and its effect on heterologous helper virus replication. Virus Res 2012; 167:97-101. [PMID: 22504338 DOI: 10.1016/j.virusres.2012.03.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 03/17/2012] [Accepted: 03/19/2012] [Indexed: 11/28/2022]
Abstract
DNA β satellites are circular single-stranded molecules associated with some monopartite begomoviruses in the family Geminiviridae. They co-infect with their helper viruses to induce severe disease in economically important crops. The βC1 protein encoded by DNA β is a pathogenicity determinant and has been reported to suppress post-transcriptional gene silencing (PTGS). The βC1 proteins from various DNA β molecules show low levels of amino acid sequence conservation. We show here that the βC1 from DNA β associated with Cotton leaf curl Multan virus (CLCuMV) is a suppressor of systemic PTGS. When this DNA β satellite co-inoculated with a heterologous helper virus, Tomato leaf curl virus (ToLCV), reduced the level of ToLCV siRNA and this was associated with a higher level of virus accumulation in infected tobacco plants. This may be a mechanism by which βC1 protects a heterologous virus from host gene silencing.
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Affiliation(s)
- Omid Eini
- School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, SA 5064, Australia. eini
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Venkataravanappa V, Lakshminarayana Reddy CN, Swaranalatha P, Jalali S, Briddon RW, Reddy MK. Diversity and phylogeography of Begomovirus-associated beta satellites of Okra in India. Virol J 2011; 8:555. [PMID: 22188644 PMCID: PMC3267694 DOI: 10.1186/1743-422x-8-555] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2011] [Accepted: 12/21/2011] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Okra (Abelmoschus esculentus; family Malvaceae) is grown in temperate as well as subtropical regions of the world, both for human consumption as a vegetable and for industrial uses. Okra yields are affected by the diseases caused by phyopathogenic viruses. India is the largest producer of okra and in this region a major biotic constraint to production are viruses of the genus Begomovirus. Begomoviruses affecting okra across the Old World are associated with specific, symptom modulating satellites (beta satellites). We describe a comprehensive analysis of the diversity of beta satellites associated with okra in India. RESULTS The full-length sequences of 36 beta satellites, isolated from okra exhibiting typical begomovirus symptoms (leaf curl and yellow vein), were determined. The sequences segregated in to four groups. Two groups correspond to the beta satellites Okra leaf curl beta satellite (OLCuB) and Bhendi yellow vein beta satellite (BYVB) that have previously been identified in okra from the sub-continent. One sequence was distinct from all other, previously isolated beta satellites and represents a new species for which we propose the name Bhendi yellow vein India beta satellite (BYVIB). This new beta satellite was nevertheless closely related to BYVB and OLCuB. Most surprising was the identification of Croton yellow vein mosaic beta satellite (CroYVMB) in okra; a beta satellite not previously identified in a malvaceous plant species. The okra beta satellites were shown to have distinct geographic host ranges with BYVB occurring across India whereas OLCuB was only identified in northwestern India. Okra infections with CroYVMB were only identified across the northern and eastern central regions of India. A more detailed analysis of the sequences showed that OLCuB, BYVB and BYVIB share highest identity with respect βC1 gene. βC1 is the only gene encoded by beta satellites, the product of which is the major pathogenicity determinant of begomovirus-beta satellite complexes and is involved in overcoming host defenses based on RNAi. CONCLUSION The diversity of beta satellites in okra across the sub-continent is higher than previously realized and is higher than for any other malvaceous plant species so far analyzed. The beta satellites identified in okra show geographic segregation, which has implications for the development and introduction of resistant okra varieties. However, the finding that the βC1 gene of the major okra beta satellites (OLCuB, BYVB and BYVIB) share high sequence identity and provides a possible avenue to achieve a broad spectrum resistance.
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Affiliation(s)
- V Venkataravanappa
- Indian Institute of Horticultural Research, Hessaraghatta Lake PO, Bangalore, India
- Indian Vegetable Research Institute, Varanasi 221305, Uttar Pradesh, India
| | - CN Lakshminarayana Reddy
- Department of Plant Pathology, College of Sericulture, University of Agricultural Sciences, Chintamani, Karnataka, India
| | - P Swaranalatha
- Indian Institute of Horticultural Research, Hessaraghatta Lake PO, Bangalore, India
| | - Salil Jalali
- Indian Institute of Horticultural Research, Hessaraghatta Lake PO, Bangalore, India
| | - Rob W Briddon
- Agricultural Biotechnology Division, National Institute for Biotechnology and Genetic Engineering, P.O. Box 577, Jhang Road, Faisalabad, Pakistan
| | - M Krishna Reddy
- Indian Institute of Horticultural Research, Hessaraghatta Lake PO, Bangalore, India
- Division of Plant Pathology, Plant Virology Laboratory, Indian Institute of Horticultural Research, Hessaraghatta Lake PO, Bangalore 560 089, India
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Shen Q, Liu Z, Song F, Xie Q, Hanley-Bowdoin L, Zhou X. Tomato SlSnRK1 protein interacts with and phosphorylates βC1, a pathogenesis protein encoded by a geminivirus β-satellite. PLANT PHYSIOLOGY 2011; 157:1394-406. [PMID: 21885668 PMCID: PMC3252149 DOI: 10.1104/pp.111.184648] [Citation(s) in RCA: 102] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2011] [Accepted: 08/29/2011] [Indexed: 05/19/2023]
Abstract
The βC1 protein of tomato yellow leaf curl China β-satellite functions as a pathogenicity determinant. To better understand the molecular basis of βC1 in pathogenicity, a yeast two-hybrid screen of a tomato (Solanum lycopersicum) cDNA library was carried out using βC1 as bait. βC1 interacted with a tomato SUCROSE-NONFERMENTING1-related kinase designated as SlSnRK1. Their interaction was confirmed using a bimolecular fluorescence complementation assay in Nicotiana benthamiana cells. Plants overexpressing SnRK1 were delayed for symptom appearance and contained lower levels of viral and satellite DNA, while plants silenced for SnRK1 expression developed symptoms earlier and accumulated higher levels of viral DNA. In vitro kinase assays showed that βC1 is phosphorylated by SlSnRK1 mainly on serine at position 33 and threonine at position 78. Plants infected with βC1 mutants containing phosphorylation-mimic aspartate residues in place of serine-33 and/or threonine-78 displayed delayed and attenuated symptoms and accumulated lower levels of viral DNA, while plants infected with phosphorylation-negative alanine mutants contained higher levels of viral DNA. These results suggested that the SlSnRK1 protein attenuates geminivirus infection by interacting with and phosphorylating the βC1 protein.
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Amin I, Hussain K, Akbergenov R, Yadav JS, Qazi J, Mansoor S, Hohn T, Fauquet CM, Briddon RW. Suppressors of RNA silencing encoded by the components of the cotton leaf curl begomovirus-betasatellite complex. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2011; 24:973-83. [PMID: 21751853 DOI: 10.1094/mpmi-01-11-0001] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Begomoviruses (family Geminiviridae) are single-stranded DNA viruses transmitted by the whitefly Bemisia tabaci. Many economically important diseases in crops are caused by begomoviruses, particularly in tropical and subtropical environments. These include the betasatellite-associated begomoviruses causing cotton leaf curl disease (CLCuD) that causes significant losses to a mainstay of the economy of Pakistan, cotton. RNA interference (RNAi) or gene silencing is a natural defense response of plants against invading viruses. In counter-defense, viruses encode suppressors of gene silencing that allow them to effectively invade plants. Here, we have analyzed the ability of the begomovirus Cotton leaf curl Multan virus (CLCuMV) and its associated betasatellite, Cotton leaf curl Multan β-satellite (CLCuMB) which, together, cause CLCuD, and the nonessential alphasatellite (Cotton leaf curl Multan alphasatellite [CLCuMA]) for their ability to suppress gene silencing in Nicotiana benthamiana. The results showed that CLCuMV by itself was unable to efficiently block silencing. However, in the presence of the betasatellite, gene silencing was entirely suppressed. Silencing was not affected in any way when infections included CLCuMA, although the alphasatellite was, for the first time, shown to be a target of RNA silencing, inducing the production in planta of specific small interfering RNAs, the effectors of silencing. Subsequently, using a quantitative real-time polymerase chain reaction assay and Northern blot analysis, the ability of all proteins encoded by CLCuMV and CLCuMB were assessed for their ability to suppress RNAi and the relative strengths of their suppression activity were compared. The analysis showed that the V2, C2, C4, and βC1 proteins exhibited suppressor activity, with the V2 showing the strongest activity. In addition, V2, C4, and βC1 were examined for their ability to bind RNA and shown to have distinct specificities. Although each of these proteins has, for other begomoviruses or betasatellites, been previously shown to have suppressor activity, this is the first time all proteins encoded by a geminiviruses (or begomovirus-betasatellite complex) have been examined and also the first for which four separate suppressors have been identified.
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Affiliation(s)
- Imran Amin
- National Institute for Biotechnology and Genetic Engineering, Faisalabad, Pakistan
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Sharma P, Gaur RK, Ikegami M. Subcellular localization of V2 protein of Tomato leaf curl Java virus by using green fluorescent protein and yeast hybrid system. PROTOPLASMA 2011; 248:281-8. [PMID: 20549267 DOI: 10.1007/s00709-010-0166-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2010] [Accepted: 05/20/2010] [Indexed: 05/29/2023]
Abstract
Tomato leaf curl Java virus-A (ToLCJV-A[ID]) from Southeast Asia is a new member of the emerging group of monopartite begomoviruses that require a betasatellite component for symptom induction. Previously, we have elucidated the role of V1 ORF encoded by ToLCJV-A[ID] in cell-to-cell movement. In this study, the role of V2 (PreCP) in localization was determined. Subcellular localization of ToLCJV-A[ID] V2 in plant tissues showed that this protein is co-localized to the cell cytoplasm, perinuclear and associated with the endoplasmic reticulum network. The results obtained from deletion analysis indicate that fusion of N-terminal part of the V2, containing the nuclear export signals (NES), directed the accumulation of fluorescence towards the cell cytoplasm. Furthermore, functionality of the NES ((20)LAVKYLQLV(29)) in the N-terminal part of the V2 protein was confirmed by one-hybrid yeast system. Taken together, these results suggest that V2 enhances the coat protein-mediated nuclear export of ToLCJV-A[ID] and is consistent with the model in which V2 mediates viral DNA export from the nucleus to the plasmodesmata.
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Affiliation(s)
- Pradeep Sharma
- Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
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Molecular characterization of tomato leaf curl China virus, infecting tomato plants in China, and functional analyses of its associated betasatellite. Appl Environ Microbiol 2011; 77:3092-101. [PMID: 21378048 DOI: 10.1128/aem.00017-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A novel tomato-infecting begomovirus from Guangxi province, China, was identified and characterized, for which the name Tomato leaf curl China virus (ToLCCNV) was proposed. Phylogenetic and recombination analyses of the virus genomic sequences suggested that ToLCCNV may have arisen by recombination among Tomato leaf curl Vietnam virus (ToLCVV), Tomato leaf curl Gujarat virus (ToLCGV), and an unknown virus. A betasatellite molecule was found to be associated with ToLCCNV (ToLCCNB), and its complete nucleotide sequences were determined. Infectious clones of ToLCCNV and ToLCCNB were constructed and then used for agro-inoculation of plants; ToLCCNV alone infected Nicotiana benthamiana, Nicotiana glutinosa, Petunia hybrida, and Solanum lycopersicum plants, but no symptoms were induced. ToLCCNB was required for induction of leaf curl disease in these hosts. The βC1 protein of ToLCCNB was identified as a suppressor of RNA silencing and accumulated primarily in the nucleus. Deletion mutagenesis of βC1 showed that the central part of βC1 (amino acids 44 to 74) was responsible for both the suppressor activity and nuclear localization.
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Sharma P, Matsuda N, Bajet NB, Ikegami M. Molecular analysis of new isolates of Tomato leaf curl Philippines virus and an associated betasatellite occurring in the Philippines. Arch Virol 2011; 156:305-12. [PMID: 21053032 DOI: 10.1007/s00705-010-0837-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2010] [Accepted: 10/09/2010] [Indexed: 11/30/2022]
Abstract
Three new begomovirus isolates and one betasatellite were obtained from a tomato plant exhibiting leaf curl symptom in Laguna, the Philippines. Typical begomovirus DNA components representing the three isolates (PH01, PH02 and PH03) were cloned, and their full-length sequences were determined to be 2754 to 2746 nucleotides. The genome organizations of these isolates were similar to those of other Old World monopartite begomoviruses. The sequence data indicated that PH01 and PH02 were variants of strain B of the species Tomato leaf curl Philippines virus, while PH03 was a variant of strain A of the species Tomato leaf curl Philippines virus. These isolates were designated ToLCPV-B[PH:Lag1:06], ToLCPV-B[PH:Lag2:06], and ToLCPV-A[PH:Lag3:06], respectively. Phylogenetic analysis revealed that the present isolates form a separate monophyletic cluster with indigenous begomoviruses reported earlier in the Philippines. A betasatellite isolated from same sample belongs to the betasatellite species Tomato leaf curl Philippines betasatellite and designated Tomato leaf curl Philippines betasatellite-[Philippines:Laguna1:2006], ToLCPHB-[PH:Lag1:06]. When co-inoculated with this betasatellite, tomato leaf curl Philippines virus induced severe symptoms in N. benthamiana and Solanum lycopersicum plants. Using a PVX-mediated transient assay, we found that the C4 and C2 proteins of tomato leaf curl Philippines virus and the βC1 protein of ToLCPHB-[PH:Lag1:06] function as a suppressor of RNA silencing.
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Affiliation(s)
- Pradeep Sharma
- Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, Miyagi, Japan.
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Zhang Z, Chen H, Huang X, Xia R, Zhao Q, Lai J, Teng K, Li Y, Liang L, Du Q, Zhou X, Guo H, Xie Q. BSCTV C2 attenuates the degradation of SAMDC1 to suppress DNA methylation-mediated gene silencing in Arabidopsis. THE PLANT CELL 2011; 23:273-88. [PMID: 21245466 PMCID: PMC3051253 DOI: 10.1105/tpc.110.081695] [Citation(s) in RCA: 158] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2010] [Revised: 11/28/2010] [Accepted: 12/22/2010] [Indexed: 05/17/2023]
Abstract
Plant viruses are excellent tools for studying microbial-plant interactions as well as the complexities of host activities. Our study focuses on the role of C2 encoded by Beet severe curly top virus (BSCTV) in the virus-plant interaction. Using BSCTV C2 as bait in a yeast two-hybrid screen, a C2-interacting protein, S-adenosyl-methionine decarboxylase 1 (SAMDC1), was identified from an Arabidopsis thaliana cDNA library. The interaction was confirmed by an in vitro pull-down assay and a firefly luciferase complemention imaging assay in planta. Biochemical analysis further showed that the degradation of the SAMDC1 protein was inhibited by MG132, a 26S proteasome inhibitor, and that C2 could attenuate the degradation of the SAMDC1 protein. Genetic analysis showed that loss of function of SAMDC1 resulted in reduced susceptibility to BSCTV infection and reduced viral DNA accumulation, similar to the effect of BSCTV C2 deficiency. Bisulfite sequencing analysis further showed that C2 deficiency caused enhanced DNA methylation of the viral genome in infected plants. We also showed that C2 can suppress de novo methylation in the FWA transgenic assay in the C2 transgene background. Overexpression of SAMDC1 can mimic the suppressive activity of C2 against green fluorescent protein-directed silencing. These results suggest that C2 interferes with the host defense mechanism of DNA methylation-mediated gene silencing by attenuating the 26S proteasome-mediated degradation of SAMDC1.
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Affiliation(s)
- Zhonghui Zhang
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen (Zhongshan) University, Guangzhou 510275, China
| | - Hao Chen
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen (Zhongshan) University, Guangzhou 510275, China
| | - Xiahe Huang
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Ran Xia
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qingzhen Zhao
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jianbin Lai
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen (Zhongshan) University, Guangzhou 510275, China
| | - Kunling Teng
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yin Li
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen (Zhongshan) University, Guangzhou 510275, China
| | - Liming Liang
- State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen (Zhongshan) University, Guangzhou 510275, China
| | - Quansheng Du
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xueping Zhou
- State Key Laboratory of Rice Biology, Institute of Biotechnology, Zhejiang University, Hangzhou 310029, China
| | - Huishan Guo
- State Key Laboratory of Plant Genomics, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qi Xie
- State Key Laboratory of Plant Genomics, National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
- Address correspondence to
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Nawaz-Ul-Rehman MS, Nahid N, Mansoor S, Briddon RW, Fauquet CM. Post-transcriptional gene silencing suppressor activity of two non-pathogenic alphasatellites associated with a begomovirus. Virology 2010; 405:300-8. [PMID: 20598726 DOI: 10.1016/j.virol.2010.06.024] [Citation(s) in RCA: 86] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Revised: 04/24/2010] [Accepted: 06/08/2010] [Indexed: 11/25/2022]
Abstract
Alphasatellites and betasatellites are begomovirus-associated single-stranded circular DNA molecules. Two distinct alphasatellites, Gossypium darwinii symptomless alphasatellite and Gossypium mustelinium symptomless alphasatellite, were previously isolated from Gossypium davidsonii and G.mustelinium. Here we show that the replication-associated proteins (Rep: a rolling-circle replication initiator protein) encoded by these alphasatellites interact with the Rep and C4 proteins encoded by their helper begomovirus, Cotton leaf curl Rajasthan virus (CLCuRaV), in a yeast two-hybrid assay. Both the alphasatellite-encoded Reps were found to have strong gene silencing suppressor activity, in contrast to the betasatellite-encoded betaC1 and CLCuRaV-encoded C2, C4 and V2 proteins. The presence of alphasatellites maintained suppression of gene silencing in the youngest, actively growing tissue of CLCuRaV-betasatellite-infected plants. This is the first demonstration of a rolling-circle replication initiator protein with suppressor of gene silencing activity and provides a possible explanation for the selective advantage provided by the association of alphasatellites with begomovirus-betasatellite complexes.
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Cotton leaf curl disease in resistant cotton is associated with a single begomovirus that lacks an intact transcriptional activator protein. Virus Res 2010; 152:153-63. [DOI: 10.1016/j.virusres.2010.06.019] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2009] [Revised: 05/02/2010] [Accepted: 06/20/2010] [Indexed: 11/22/2022]
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Sharma P, Ikegami M, Kon T. Identification of the virulence factors and suppressors of posttranscriptional gene silencing encoded by Ageratum yellow vein virus, a monopartite begomovirus. Virus Res 2010; 149:19-27. [PMID: 20079777 DOI: 10.1016/j.virusres.2009.12.008] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 11/17/2009] [Accepted: 12/30/2009] [Indexed: 11/30/2022]
Abstract
Ageratum yellow vein disease (AYVD) is caused by the association of a Tomato leaf curl Java betasatellite [Indonesia:Indonesia 1:2003] (ToLCJB-[ID:ID1:03]) with a begomovirus component. Our previous results demonstrated that ToLCJB-[ID:ID:03] is essential for induction of leaf curl symptoms in plants and transgene expression of its betaC1 gene in Nicotiana benthamiana plants induces virus-like symptoms. Here we show that Ageratum yellow vein virus-Indonesia [Indonesia: Tomato] (AYVV-ID[ID:Tom]) alone could systemically infect the plants and induced upward leaf curl symptoms. ToLCJB-[ID:ID1:03] was required, in addition to AYVV-ID[ID:Tom], for induction of severe downward leaf curl disease in N. benthamiana plants. However, DNAbeta01fsbetaC1, which encompasses a frameshift mutation, did not induce severe symptoms in N. benthamiana when co-inoculated with AYVV-ID[ID:Tom]. The infectivity analysis of AYVV-ID[ID:Tom] and its associated betasatellite encoded genes using Potato virus X (PVX) vector were carried out in N. benthamiana, indicate that the V2 and betaC1 genes are symptom determinants. We have identified the DNA encoded V2 and its betasatellite, ToLCJB-[ID:ID1:03], encoded betaC1 proteins as efficient silencing suppressors of posttranscriptional gene silencing (PTGS) by using an Agrobacterium co-infiltration or heterologous PVX vector assays. However, the results also showed weak suppression of gene silencing activities for C2 and C4 induced by GFP and mRNA associated with GFP was detected. Furthermore, confocal imaging analysis of ToLCJB-[ID:ID1:03] betaC1 in the epidermal cells of N. benthamiana shows that this protein is accumulated towards the periphery of the cell and around the nucleus, however, V2 accumulated in the cell cytoplasm, C4 associated with plasma membrane and C2 exclusively targeted into nucleus. In this study, we identified as many as four distinct suppressors of RNA silencing encoded by AYVV-ID[ID:Tom] and its cognate betasatellite in the family Geminiviridae, counteracting innate antiviral response.
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Affiliation(s)
- P Sharma
- Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amemiyamachi, Aoba-ku, Sendai, Miyagi 981-8555, Japan.
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Sharma P, Ikegami M. Tomato leaf curl Java virus V2 protein is a determinant of virulence, hypersensitive response and suppression of posttranscriptional gene silencing. Virology 2009; 396:85-93. [PMID: 19896687 DOI: 10.1016/j.virol.2009.10.012] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2009] [Revised: 10/01/2009] [Accepted: 10/07/2009] [Indexed: 11/29/2022]
Abstract
We previously identified the Tomato leaf curl Java virus-A (ToLCJV-A[ID]) from Southeast Asia as a new member of the emerging group of monopartite begomoviruses that require a betasatellite component for symptom induction. In this study, the role of V2 in viral pathogenesis and posttranscriptional gene silencing (PTGS) was studied. Our results showed V2 of ToLCJV-A[ID] elicits a reaction resembling the hypersensitive response (HR) associated with the induction of necrosis and a systemic burst of H(2)O(2) production when expressed from a potato virus X vector in Nicotiana species and tomato. Transient expression of ToLCJV-A[ID] V2 after agroinfiltration of Nicotiana benthamiana and tomato also triggered HR-like cell death, demonstrating that ToLCJV-A[ID] V2 is a target of host defense responses. Deletion of 58 amino acids (aa) from the N-terminus did not affect the HR, suggesting that this region has no role in the HR, while deletion of 58 aa from the C-terminus of V2 abolished both the HR response and V2 silencing suppressor activity, suggesting that these sequences are required for the HR-like response and suppression of PTGS. This finding demonstrated that ToLCJV-A[ID] V2 is a pathogenicity determinant that elicits an HR-like response.
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Affiliation(s)
- Pradeep Sharma
- Department of Life Science, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
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Eini O, Dogra S, Selth LA, Dry IB, Randles JW, Rezaian MA. Interaction with a host ubiquitin-conjugating enzyme is required for the pathogenicity of a geminiviral DNA beta satellite. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2009; 22:737-46. [PMID: 19445598 DOI: 10.1094/mpmi-22-6-0737] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
DNA beta is a single-stranded satellite DNA which encodes a single gene, betaC1. To better understand the role of betaC1 in the pathogenicity of DNA beta, a yeast two-hybrid screen of a tomato cDNA library was carried out using betaC1 from Cotton leaf curl Multan virus (CLCuMV) DNA beta as the bait. A ubiquitin-conjugating enzyme, designated SlUBC3, which functionally complemented a yeast mutant deficient in ubiquitin-conjugating enzymes was identified. The authenticity and specificity of the interaction between betaC1 and SlUBC3 was confirmed both in vivo, using a bimolecular fluorescence complementation assay, and in vitro, using a protein-binding assay. Analysis of deletion mutants of the betaC1 protein showed that a myristoylation-like motif is required both for its interaction with SlUBC3 and the induction of DNA-beta-specific symptoms in host plants. The level of polyubiquitinated proteins in transgenic tobacco plants expressing betaC1 was found to be reduced compared with wild-type plants. These results are consistent with the hypothesis that interaction of betaC1 with SlUBC3 is required for DNA-beta-specific symptom induction, and that this is possibly due to downregulation of the host ubiquitin proteasome pathway.
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Affiliation(s)
- Omid Eini
- School of Agriculture, Food and Wine, The University of Adelaide, Waite Campus, SA 5064, Australia.
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Sharma P, Ikegami M. Characterization of signals that dictate nuclear/nucleolar and cytoplasmic shuttling of the capsid protein of Tomato leaf curl Java virus associated with DNA beta satellite. Virus Res 2009; 144:145-53. [PMID: 19409945 DOI: 10.1016/j.virusres.2009.04.019] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2008] [Revised: 04/21/2009] [Accepted: 04/24/2009] [Indexed: 01/25/2023]
Abstract
Transport of the viral genome into the nucleus is an obligatory step in the replication cycle of geminiviruses. Capsid proteins (CPs) of geminiviruses are multifunctional proteins thought to be involved in this process. The CP of monopartite geminiviruses is absolutely essential for virus movement. To more precisely examine the role of CP, we have constructed a series of single and double deletions into the coding sequence of Tomato leaf curl Java virus (ToLCJAV) CP and examined sub-cellular localization using transient expression of GFP fusion proteins. In this report, the domains of the CP encoded by ToLCJAV localized in the nucleus/nucleolus and cytoplasm in transfected cells were mapped. Deletion analysis revealed that the Arg-rich cluster from amino acids (aa) (16)KVRRR(20) in the N-terminal region of CP functioned as nuclear/nucleolar localization signals (NLSs). The region from aa (52)RKPR(55) contained basic amino acid cluster was capable to redirect the CP to the nucleus. Further, both transient expression and yeast hybrid assays demonstrated that CP was capable of shuttling between the nucleus and cytoplasm of the cell. Deletion mutant analysis revealed that this property was attributed to a nuclear export signal (NES) sequence consisted of aa ((245)LKIRIY(250)) reside at C-terminal part of CP. This hydrophobic region caused transport of GFP to the cytoplasm. However, ToLCJAV CP NLSs and NES show peculiarities in the number and position of basic residues. Taken together, these results demonstrated that ToLCJAV CP shuttles between the nucleus and cytoplasm, such an activity homolog to bipartite geminivirus BV1 ORF.
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Affiliation(s)
- P Sharma
- Department of Life Science, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori - Amamiyamachi, Aoba-ku, Sendai 981-8555, Japan.
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Chen LF, Rojas M, Kon T, Gamby K, Xoconostle-Cazares B, Gilbertson RL. A severe symptom phenotype in tomato in Mali is caused by a reassortant between a novel recombinant begomovirus (Tomato yellow leaf curl Mali virus) and a betasatellite. MOLECULAR PLANT PATHOLOGY 2009; 10:415-30. [PMID: 19400843 PMCID: PMC6640326 DOI: 10.1111/j.1364-3703.2009.00541.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Tomato production in West Africa has been severely affected by begomovirus diseases, including yellow leaf curl and a severe symptom phenotype, characterized by extremely stunted and distorted growth and small deformed leaves. Here, a novel recombinant begomovirus from Mali, Tomato yellow leaf curl Mali virus (TYLCMLV), is described that, alone, causes tomato yellow leaf curl disease or, in combination with a betasatellite, causes the severe symptom phenotype. TYLCMLV is an Old World monopartite begomovirus with a hybrid genome composed of sequences from Tomato yellow leaf curl virus-Mild (TYLCV-Mld) and Hollyhock leaf crumple virus (HoLCrV). A TYLCMLV infectious clone induced leaf curl and yellowing in tomato, leaf curl, crumpling and yellowing in Nicotiana benthamiana and common bean, mild symptoms in N. glutinosa, and a symptomless infection in Datura stramonium. In a field-collected sample from a tomato plant showing the severe symptom phenotype in Mali, TYLCMLV was detected together with a betasatellite, identified as Cotton leaf curl Gezira betasatellite (CLCuGB). Tomato plants co-agroinoculated with TYLCMLV and CLCuGB developed severely stunted and distorted growth and small crumpled leaves. These symptoms were more severe than those induced by TYLCMLV alone, and were similar to the severe symptom phenotype observed in the field in Mali and in other West African countries. TYLCMLV and CLCuGB also induced more severe symptoms than TYLCMLV in the other solanaceous hosts, but not in common bean. The increased symptom severity was associated with hyperplasia of phloem-associated cells, but relatively little increase in TYLCMLV DNA levels. In surveys of tomato virus diseases in West Africa, TYLCMLV was commonly detected in plants with leaf curl and yellow leaf curl symptoms, whereas CLCuGB was infrequently detected and always in association with the severe symptom phenotype. Together, these results indicate that TYLCMLV causes tomato yellow leaf curl disease throughout West Africa, whereas TYLCMLV and CLCuGB represent a reassortant that causes the severe symptom phenotype in tomato.
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Affiliation(s)
- Li-Fang Chen
- Department of Plant Pathology, University of California, Davis, CA 95616, USA
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Kon T, Rojas MR, Abdourhamane IK, Gilbertson RL. Roles and interactions of begomoviruses and satellite DNAs associated with okra leaf curl disease in Mali, West Africa. J Gen Virol 2009; 90:1001-1013. [PMID: 19264648 DOI: 10.1099/vir.0.008102-0] [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] [Indexed: 11/18/2022] Open
Abstract
Okra leaf curl disease (OLCD) is a major constraint on okra (Abelmoschus esculentus) production in West Africa. Two monopartite begomoviruses (okra virus-1 and okra virus-2), a betasatellite and a DNA1 satellite are associated with OLCD in Mali. Okra virus-1 is an isolate of okra yellow crinkle virus (OYCrV), okra virus-2 is a recombinant isolate of cotton leaf curl Gezira virus (CLCuGV) and the betasatellite is a variant of cotton leaf curl Gezira betasatellite (CLCuGB). Cloned DNA of OYCrV and CLCuGV were infectious and induced leaf curl symptoms in Nicotiana benthamiana plants, but did not induce OLCD in okra. However, when these clones were individually co-inoculated with the cloned CLCuGB DNA, symptom severity and viral DNA levels were increased in N. benthamiana plants and typical OLCD symptoms were induced in okra. The CLCuGB was also replicated by, and increased symptom severity of, three monopartite tomato-infecting begomoviruses, including two from West Africa. The sequence of the DNA1 satellite was highly divergent, indicating that it represents a distinct West African lineage. DNA1 replicated autonomously, and replication required the DNA1-encoded Rep protein. Although DNA1 reduced helper begomovirus DNA levels, symptoms were not attenuated. In the presence of CLCuGB, DNA levels of the helper begomoviruses and DNA1 were substantially increased. Together, these findings establish that OLCD in Mali is caused by a complex of monopartite begomoviruses and a promiscuous betasatellite with an associated parasitic DNA1 satellite. These findings are discussed in terms of the aetiology of OLCD and the evolution of new begomovirus/satellite DNA complexes.
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Affiliation(s)
- Tatsuya Kon
- Department of Plant Pathology, University of California, Davis, CA 95616, USA
| | - Maria R Rojas
- Department of Plant Pathology, University of California, Davis, CA 95616, USA
| | | | - Robert L Gilbertson
- Department of Plant Pathology, University of California, Davis, CA 95616, USA
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Varsani A, Shepherd DN, Dent K, Monjane AL, Rybicki EP, Martin DP. A highly divergent South African geminivirus species illuminates the ancient evolutionary history of this family. Virol J 2009; 6:36. [PMID: 19321000 PMCID: PMC2666655 DOI: 10.1186/1743-422x-6-36] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Accepted: 03/25/2009] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We have characterised a new highly divergent geminivirus species, Eragrostis curvula streak virus (ECSV), found infecting a hardy perennial South African wild grass. ECSV represents a new genus-level geminivirus lineage, and has a mixture of features normally associated with other specific geminivirus genera. RESULTS Whereas the ECSV genome is predicted to express a replication associated protein (Rep) from an unspliced complementary strand transcript that is most similar to those of begomoviruses, curtoviruses and topocuviruses, its Rep also contains what is apparently a canonical retinoblastoma related protein interaction motif such as that found in mastreviruses. Similarly, while ECSV has the same unusual TAAGATTCC virion strand replication origin nonanucleotide found in another recently described divergent geminivirus, Beet curly top Iran virus (BCTIV), the rest of the transcription and replication origin is structurally more similar to those found in begomoviruses and curtoviruses than it is to those found in BCTIV and mastreviruses. ECSV also has what might be a homologue of the begomovirus transcription activator protein gene found in begomoviruses, a mastrevirus-like coat protein gene and two intergenic regions. CONCLUSION Although it superficially resembles a chimaera of geminiviruses from different genera, the ECSV genome is not obviously recombinant, implying that the features it shares with other geminiviruses are those that were probably present within the last common ancestor of these viruses. In addition to inferring how the ancestral geminivirus genome may have looked, we use the discovery of ECSV to refine various hypotheses regarding the recombinant origins of the major geminivirus lineages.
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Affiliation(s)
- Arvind Varsani
- School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand
- Electron Microscope Unit, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
| | - Dionne N Shepherd
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
| | - Kyle Dent
- Electron Microscope Unit, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
| | - Aderito L Monjane
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
| | - Edward P Rybicki
- Department of Molecular and Cell Biology, University of Cape Town, Rondebosch, Cape Town, 7701, South Africa
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa
| | - Darren P Martin
- Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Observatory, Cape Town, 7925, South Africa
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Matsuda N, Sharma P, Bajet NB, Ikegami M. Molecular characterization of a new strain of tomato leaf curl Philippines virus and its associated satellite DNAbeta molecule: further evidence for natural recombination amongst begomoviruses. Arch Virol 2008; 153:961-7. [PMID: 18357407 DOI: 10.1007/s00705-008-0065-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2007] [Accepted: 02/11/2008] [Indexed: 11/24/2022]
Affiliation(s)
- N Matsuda
- Department of Life Science, Graduate School of Agricultural Science, Tohoku University, 1-1 Tsutsumidori-Amamiyamachi, Aoba-ku, Sendai, Miyagi 981-8555, Japan
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Abstract
Although emerging plant viruses receive much less publicity than their animal- or human-infecting cousins, they pose a serious threat to worldwide agricultural production. These viruses can be new (i.e., not previously known) or already known; however, they share the common characteristic of occupying and spreading within new niches. Factors driving the emergence of plant viruses include genetic variability in the virus, changes in agricultural practices, increases in the population and/or distribution of insect vectors and long-distance transport of plant materials. In recent years, individual as well as entire groups of viruses have emerged, and this has involved a variety of mechanism(s), depending on the virus and the environment. Here, we will discuss some of these viruses, and highlight the mechanisms that have mediated their emergence. Special emphasis is placed upon the whiteflytransmitted geminiviruses (begomoviruses) and the thrips-transmitted tosposviruses, which have emerged as major threats to crop production throughout the world. Other examples include the recent emergence of novel viruslike agents, the acquisition and role of satellite DNA or RNA molecules in emergence of plant viruses, and cases where emerging viruses have had only a transient impact. It seems clear that global movement of plant materials, expansion of agriculture and large-scale monoculture will continue to favor emergence of plant viruses. However, improved diagnostics should allow for rapid identification of emerging viruses and better understanding of viral biology. This information can be used in the development of effective management strategies, which will hopefully minimize impact on agricultural production.
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