1
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Kwon SJ, Lee YJ, Cho YE, Byun HS, Seo JK. Engineering of stable infectious cDNA constructs of a fluorescently tagged tomato chlorosis virus. Virology 2024; 593:110010. [PMID: 38364352 DOI: 10.1016/j.virol.2024.110010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Revised: 01/15/2024] [Accepted: 01/26/2024] [Indexed: 02/18/2024]
Abstract
Tomato chlorosis virus (ToCV) is an emerging pathogen that cause severe yellow leaf disorder syndrome in tomato plants. In this study, we aimed to generate a recombinant ToCV tagged with green fluorescent protein (GFP) to enable real-time monitoring of viral infection in living plants. Transformation of the full-length cDNA construct of ToCV RNA1 into Escherichia coli resulted in instability issues, which were successfully overcome by inserting a plant intron into RNA1. Subsequently, a GFP tag was engineered into a cDNA construct of ToCV RNA2. The resulting recombinant ToCV-GFP could systemically infect Nicotiana benthamiana plants, and GFP expression was observed along the major veins. Utilizing ToCV-GFP, we also showed that ToCV engages in antagonistic relationships with two different tomato-infecting viruses in mixed infections in N. benthamiana. This study demonstrates the potential of ToCV-GFP as a valuable tool for the visual tracking of infection and movement of criniviruses in living plants.
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Affiliation(s)
- Sun-Jung Kwon
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang 25354, Republic of Korea
| | - Ye-Ji Lee
- Crop Protection Division, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Republic of Korea
| | - Young-Eun Cho
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang 25354, Republic of Korea
| | - Hee-Seong Byun
- Crop Protection Division, National Institute of Agricultural Sciences, Rural Development Administration, Wanju 55365, Republic of Korea
| | - Jang-Kyun Seo
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang 25354, Republic of Korea; Department of International Agricultural Technology, Seoul National University, Pyeongchang 25354, Republic of Korea.
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2
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Kim MH, Choi B, Jang SY, Choi JS, Kim S, Lee Y, Park S, Kwon SJ, Kang JH, Seo JK. The VP53 protein encoded by RNA2 of a fabavirus, broad bean wilt virus 2, is essential for viral systemic infection. Commun Biol 2024; 7:462. [PMID: 38627534 PMCID: PMC11021446 DOI: 10.1038/s42003-024-06170-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 04/09/2024] [Indexed: 04/19/2024] Open
Abstract
Plant viruses evolves diverse strategies to overcome the limitations of their genomic capacity and express multiple proteins, despite the constraints imposed by the host translation system. Broad bean wilt virus 2 (BBWV2) is a widespread viral pathogen, causing severe damage to economically important crops. It is hypothesized that BBWV2 RNA2 possesses two alternative in-frame translation initiation codons, resulting in the production of two largely overlapping proteins, VP53 and VP37. In this study, we aim to investigate the expression and function of VP53, an N-terminally 128-amino-acid-extended form of the viral movement protein VP37, during BBWV2 infection. By engineering various recombinant and mutant constructs of BBWV2 RNA2, here we demonstrate that VP53 is indeed expressed during BBWV2 infection. We also provide evidence of the translation of the two overlapping proteins through ribosomal leaky scanning. Furthermore, our study highlights the indispensability of VP53 for successful systemic infection of BBWV2, as its removal results in the loss of virus infectivity. These insights into the translation mechanism and functional role of VP53 during BBWV2 infection significantly contribute to our understanding of the infection mechanisms employed by fabaviruses.
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Affiliation(s)
- Myung-Hwi Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Republic of Korea
| | - Boram Choi
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Seok-Yeong Jang
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Ji-Soo Choi
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Sora Kim
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Yubin Lee
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Suejin Park
- Department of Horticulture, Jeonbuk National University, Jeonju, 54896, Republic of Korea
| | - Sun-Jung Kwon
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Jin-Ho Kang
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Jang-Kyun Seo
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Republic of Korea.
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea.
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea.
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3
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Qiao Z, Wang J, Huang K, Hu H, Gu Z, Liao Q, Du Z. The non-template functions of helper virus RNAs create optimal replication conditions to enhance the proliferation of satellite RNAs. PLoS Pathog 2024; 20:e1012174. [PMID: 38630801 PMCID: PMC11057728 DOI: 10.1371/journal.ppat.1012174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 04/29/2024] [Accepted: 04/07/2024] [Indexed: 04/19/2024] Open
Abstract
As a type of parasitic agent, satellite RNAs (satRNAs) rely on cognate helper viruses to achieve their replication and transmission. During the infection of satRNAs, helper virus RNAs serve as templates for synthesizing viral proteins, including the replication proteins essential for satRNA replication. However, the role of non-template functions of helper virus RNAs in satRNA replication remains unexploited. Here we employed the well-studied model that is composed of cucumber mosaic virus (CMV) and its associated satRNA. In the experiments employing the CMV trans-replication system, we observed an unexpected phenomenon the replication proteins of the mild strain LS-CMV exhibited defective in supporting satRNA replication, unlike those of the severe strain Fny-CMV. Independent of translation products, all CMV genomic RNAs could enhance satRNA replication, when combined with the replication proteins of CMV. This enhancement is contingent upon the recruitment and complete replication of helper virus RNAs. Using the method developed for analyzing the satRNA recruitment, we observed a markedly distinct ability of the replication proteins from both CMV strains to recruit the positive-sense satRNA-harboring RNA3 mutant for replication. This is in agreement with the differential ability of both 1a proteins in binding satRNAs in plants. The discrepancies provide a convincing explanation for the variation of the replication proteins of both CMV strains in replicating satRNAs. Taken together, our work provides compelling evidence that the non-template functions of helper virus RNAs create an optimal replication environment to enhance satRNA proliferation.
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Affiliation(s)
- Zimu Qiao
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
| | - Jin Wang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
| | - Kaiyun Huang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
| | - Honghao Hu
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
| | - Zhouhang Gu
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
| | - Qiansheng Liao
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
| | - Zhiyou Du
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang, China
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4
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Li M, Zhang X, Huang K, Du Z. Identification of Host Factors Interacting with a γ-Shaped RNA Element from a Plant Virus-Associated Satellite RNA. Viruses 2023; 15:2039. [PMID: 37896816 PMCID: PMC10611174 DOI: 10.3390/v15102039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 09/28/2023] [Accepted: 09/29/2023] [Indexed: 10/29/2023] Open
Abstract
Previously, we identified a highly conserved, γ-shaped RNA element (γRE) from satellite RNAs of cucumber mosaic virus (CMV), and we determined γRE to be structurally required for satRNA survival and the inhibition of CMV replication. It remains unknown how γRE biologically functions. In this work, pull-down assays were used to screen candidates of host factors from Nicotiana benthamiana plants using biotin-labeled γRE as bait. Nine host factors were found to interact specifically with γRE. Then, all of these host factors were down-regulated individually in N. benthamiana plants via tobacco rattle virus-induced gene silencing and tested with infection by GFP-expressing CMV (CMV-gfp) and the isolate T1 of satRNA (sat-T1). Out of nine candidates, three host factors, namely histone H3, GTPase Ran3, and eukaryotic translation initiation factor 4A, were extremely important for infection by CMV-gfp and sat-T1. Moreover, we found that cytosolic glyceraldehyde-3-phosphate dehydrogenase 2 contributed to the replication of CMV and sat-T1, but also negatively regulated CMV 2b activity. Collectively, our work provides essential clues for uncovering the mechanism by which satRNAs inhibit CMV replication.
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Affiliation(s)
| | | | | | - Zhiyou Du
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou 310018, China
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5
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Kwon MJ, Kwon SJ, Kim MH, Choi B, Byun HS, Kwak HR, Seo JK. Visual tracking of viral infection dynamics reveals the synergistic interactions between cucumber mosaic virus and broad bean wilt virus 2. Sci Rep 2023; 13:7261. [PMID: 37142679 PMCID: PMC10160061 DOI: 10.1038/s41598-023-34553-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Accepted: 05/03/2023] [Indexed: 05/06/2023] Open
Abstract
Cucumber mosaic virus (CMV) is one of the most prevalent plant viruses in the world, and causes severe damage to various crops. CMV has been studied as a model RNA virus to better understand viral replication, gene functions, evolution, virion structure, and pathogenicity. However, CMV infection and movement dynamics remain unexplored due to the lack of a stable recombinant virus tagged with a reporter gene. In this study, we generated a CMV infectious cDNA construct tagged with a variant of the flavin-binding LOV photoreceptor (iLOV). The iLOV gene was stably maintained in the CMV genome after more than four weeks of three serial passages between plants. Using the iLOV-tagged recombinant CMV, we visualized CMV infection and movement dynamics in living plants in a time course manner. We also examined whether CMV infection dynamics is influenced by co-infection with broad bean wilt virus 2 (BBWV2). Our results revealed that no spatial interference occurred between CMV and BBWV2. Specifically, BBWV2 facilitated the cell-to-cell movement of CMV in the upper young leaves. In addition, the BBWV2 accumulation level increased after co-infection with CMV.
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Affiliation(s)
- Min-Jun Kwon
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Sun-Jung Kwon
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Myung-Hwi Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Republic of Korea
| | - Boram Choi
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea
| | - Hee-Seong Byun
- Crop Protection Division, National Institute of Agricultural Sciences, Rural Development Administration, Wanju, 55365, Republic of Korea
| | - Hae-Ryun Kwak
- Crop Protection Division, National Institute of Agricultural Sciences, Rural Development Administration, Wanju, 55365, Republic of Korea
| | - Jang-Kyun Seo
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea.
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, 25354, Republic of Korea.
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826, Republic of Korea.
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6
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Kwon SJ, Han SJ, Kim MH, Jang SY, Choi JS, Seo JK. Ethylene emitted by viral pathogen-infected pepper ( Capsicum annuum L.) plants is a volatile chemical cue that attracts aphid vectors. FRONTIERS IN PLANT SCIENCE 2022; 13:994314. [PMID: 36247604 PMCID: PMC9559363 DOI: 10.3389/fpls.2022.994314] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 09/07/2022] [Indexed: 05/22/2023]
Abstract
Plant viruses are obligate intracellular pathogens, and most depend on insect vectors for transmission between plants. Viral infection causes various physiological and metabolic changes in host traits, which subsequently influence the behavior and fitness of the insect vectors. Cucumber mosaic virus (CMV), one of the most widespread pathogens in pepper (Capsicum annuum L.), is transmitted by aphid vectors in a non-persistent manner. Here, we examined whether CMV infection in pepper affects the behavior of aphid vectors (Myzus persicae and Aphis glycines) in pepper. Aphid preference test revealed that significantly more aphids were attracted to CMV-infected pepper plants than to healthy plants. Comparative transcriptome analysis revealed a significant activation of the ethylene biosynthesis pathway in CMV-infected pepper plants. Indeed, gas chromatography analysis demonstrated that ethylene emission was significantly increased by CMV infection in pepper plants. Elevated ethylene emission in ethephon-treated healthy pepper increased their attractiveness to aphids. In contrast, aphid preference decreased after chemical inhibition of ethylene biosynthesis in CMV-infected pepper plants. Our results suggest that the ethylene emitted by CMV infection is a volatile cue that regulates the attractiveness of pepper plants to M. persicae and A. glycines.
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Affiliation(s)
- Sun-Jung Kwon
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, South Korea
| | - Soo-Jung Han
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, South Korea
| | - Myung-Hwi Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
| | - Seok-Yeong Jang
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, South Korea
| | - Ji-Soo Choi
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, South Korea
| | - Jang-Kyun Seo
- Institutes of Green Bio Science and Technology, Seoul National University, Pyeongchang, South Korea
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, South Korea
- Department of Agricultural Biotechnology, Seoul National University, Seoul, South Korea
- Integrated Major in Global Smart Farm, Seoul National University, Seoul, South Korea
- *Correspondence: Jang-Kyun Seo,
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7
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Han SJ, Choi B, Kim MH, Kwon SJ, Kwak HR, Seo JK. Viral Strain-Specific Activation of Pathogen-Associated Molecular Pattern-Triggered Immunity Enhances Symptom Severity in Broad Bean Wilt Virus 2 Infection. FRONTIERS IN PLANT SCIENCE 2021; 12:746543. [PMID: 34721473 PMCID: PMC8549444 DOI: 10.3389/fpls.2021.746543] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 08/24/2021] [Indexed: 05/22/2023]
Abstract
Broad bean wilt virus 2 (BBWV2) is an emerging virus in various economically important crops, especially pepper (Capsicum annuum L.), worldwide. Recently, the emergence of various BBWV2 strains that induce severe symptoms has increased damage to pepper crops. While the symptomatic variations among virus strains should be associated with differences in the transcriptomic reprogramming of host plants upon infection, underlying molecular mechanisms and associated genes are largely unknown. In the present study, we employed transcriptome analysis to identify responsible host factors for symptom enhancement in the BBWV2-pepper pathosystem using two distinct BBWV2 strains, PAP1 (a severe strain) and RP1 (a mild strain). Comparative analysis of the differentially expressed genes (DEGs) revealed that various genes associated with pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) and ethylene signaling were significantly upregulated upon infection with the severe PAP1 strain, but not with the mild RP1 strain. Indeed, hormone analysis revealed that ethylene emission was significantly increased in pepper plants infected with PAP1. These observations imply that the activation of the PTI-associated defense responses reinforce symptom formation during BBWV2 infection in a virus strain-specific manner.
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Affiliation(s)
- Soo-Jung Han
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, South Korea
| | - Boram Choi
- Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang, South Korea
| | - Myung-Hwi Kim
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, South Korea
- Integrated Major in Global Smart Farm, Seoul National University, Seoul, South Korea
| | - Sun-Jung Kwon
- Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang, South Korea
| | - Hae-Ryun Kwak
- Crop Protection Division, Rural Development Administration, National Institute of Agricultural Sciences, Wanju, South Korea
| | - Jang-Kyun Seo
- Department of International Agricultural Technology, Seoul National University, Pyeongchang, South Korea
- Institute of Green Bio Science and Technology, Seoul National University, Pyeongchang, South Korea
- Integrated Major in Global Smart Farm, Seoul National University, Seoul, South Korea
- *Correspondence: Jang-Kyun Seo,
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8
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Heo KJ, Kwon SJ, Kim MK, Kwak HR, Han SJ, Kwon MJ, Rao ALN, Seo JK. Newly emerged resistance-breaking variants of cucumber mosaic virus represent ongoing host-interactive evolution of an RNA virus. Virus Evol 2020; 6:veaa070. [PMID: 33240527 PMCID: PMC7673075 DOI: 10.1093/ve/veaa070] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Understanding the evolutionary history of a virus and the mechanisms influencing the direction of its evolution is essential for the development of more durable strategies to control the virus in crop fields. While the deployment of host resistance in crops is the most efficient means to control various viruses, host resistance itself can act as strong selective pressure and thus play a critical role in the evolution of virus virulence. Cucumber mosaic virus (CMV), a plant RNA virus with high evolutionary capacity, has caused endemic disease in various crops worldwide, including pepper (Capsicum annuum L.), because of frequent emergence of resistance-breaking variants. In this study, we examined the molecular and evolutionary characteristics of recently emerged, resistance-breaking CMV variants infecting pepper. Our population genetics analysis revealed that the high divergence capacity of CMV RNA1 might have played an essential role in the host-interactive evolution of CMV and in shaping the CMV population structure in pepper. We also demonstrated that nonsynonymous mutations in RNA1 encoding the 1a protein enabled CMV to overcome the deployed resistance in pepper. Our findings suggest that resistance-driven selective pressures on RNA1 might have contributed in shaping the unique evolutionary pattern of CMV in pepper. Therefore, deployment of a single resistance gene may reduce resistance durability against CMV and more integrated approaches are warranted for successful control of CMV in pepper.
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Affiliation(s)
| | - Sun-Jung Kwon
- Institutes of Green Bio Science and Technology, Seoul National University, 1447 Pyeongchang-ro, Pyeongchang 25354, Republic of Korea
| | - Mi-Kyeong Kim
- Department of Plant Medicine, Chungbuk National University, 1 Chungdae-ro, Cheongju 28644, Republic of Korea
| | - Hae-Ryun Kwak
- Crop Protection Division, National Institute of Agricultural Sciences, Rural Development Administration, 300 Nongsaengmyeong-ro, Wanju 55365, Republic of Korea
| | - Soo-Jung Han
- Department of International Agricultural Technology
| | - Min-Jun Kwon
- Department of International Agricultural Technology
| | - A L N Rao
- Department of Microbiology and Plant Pathology, University of California, Boyce Hall 1463, 900 University Ave, Riverside, CA 92521, USA
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Tian A, Miyashita S, Ando S, Takahashi H. Single Amino Acid Substitutions in the Cucumber Mosaic Virus 1a Protein Induce Necrotic Cell Death in Virus-Inoculated Leaves without Affecting Virus Multiplication. Viruses 2020; 12:v12010091. [PMID: 31941092 PMCID: PMC7019621 DOI: 10.3390/v12010091] [Citation(s) in RCA: 5] [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: 10/04/2019] [Revised: 01/08/2020] [Accepted: 01/09/2020] [Indexed: 11/24/2022] Open
Abstract
When Arabidopsis thaliana ecotype Col-0 was inoculated with a series of reassortant viruses created by exchanging viral genomic RNAs between two strains of cucumber mosaic virus (CMV), CMV(Y), and CMV(H), cell death developed in the leaves inoculated with reassortant CMV carrying CMV(H) RNA1 encoding 1a protein, but not in noninoculated upper leaves. In general, cell death in virus-infected plants is a critical event for virus survival because virus multiplication is completely dependent on host cell metabolism. However, interestingly, this observed cell death did not affect either virus multiplication in the inoculated leaves or systemic spread to noninoculated upper leaves. Furthermore, the global gene expression pattern of the reassortant CMV-inoculated leaves undergoing cell death was clearly different from that in hypersensitive response (HR) cell death, which is coupled with resistance to CMV. These results indicated that the observed cell death does not appear to be HR cell death but rather necrotic cell death unrelated to CMV resistance. Interestingly, induction of this necrotic cell death depended on single amino acid substitutions in the N-terminal region surrounding the methyltransferase domain of the 1a protein. Thus, development of necrotic cell death might not be induced by non-specific damage as a result of virus multiplication, but by a virus protein-associated mechanism. The finding of CMV 1a protein-mediated induction of necrotic cell death in A. thaliana, which is not associated with virus resistance and HR cell death, has the potential to provide a new pathosystem to study the role of cell death in virus–host plant interactions.
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10
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He L, Wang Q, Gu Z, Liao Q, Palukaitis P, Du Z. A conserved RNA structure is essential for a satellite RNA-mediated inhibition of helper virus accumulation. Nucleic Acids Res 2019; 47:8255-8271. [PMID: 31269212 PMCID: PMC6735963 DOI: 10.1093/nar/gkz564] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 05/30/2019] [Accepted: 06/20/2019] [Indexed: 12/15/2022] Open
Abstract
As a class of parasitic, non-coding RNAs, satellite RNAs (satRNAs) have to compete with their helper virus for limited amounts of viral and/or host resources for efficient replication, by which they usually reduce viral accumulation and symptom expression. Here, we report a cucumber mosaic virus (CMV)-associated satRNA (sat-T1) that ameliorated CMV-induced symptoms, accompanied with a significant reduction in the accumulation of viral genomic RNAs 1 and 2, which encode components of the viral replicase. Intrans replication assays suggest that the reduced accumulation is the outcome of replication competition. The structural basis of sat-T1 responsible for the inhibition of viral RNA accumulation was determined to be a three-way branched secondary structure that contains two biologically important hairpins. One is indispensable for the helper virus inhibition, and the other engages in formation of a tertiary pseudoknot structure that is essential for sat-T1 survival. The secondary structure containing the pseudoknot is the first RNA element with a biological phenotype experimentally identified in CMV satRNAs, and it is structurally conserved in most CMV satRNAs. Thus, this may be a generic method for CMV satRNAs to inhibit the accumulation of the helper virus via the newly-identified RNA structure.
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Affiliation(s)
- Lu He
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Qian Wang
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Zhouhang Gu
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Qiansheng Liao
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Peter Palukaitis
- Department of Horticultural Sciences, Seoul Women's University, Nowon-gu, Seoul 01797, Republic of Korea
| | - Zhiyou Du
- College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
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11
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Liu D, Zhao Q, Cheng Y, Li D, Jiang C, Cheng L, Wang Y, Yang A. Transcriptome analysis of two cultivars of tobacco in response to Cucumber mosaic virus infection. Sci Rep 2019; 9:3124. [PMID: 30816259 PMCID: PMC6395745 DOI: 10.1038/s41598-019-39734-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 01/31/2019] [Indexed: 01/23/2023] Open
Abstract
Cucumber mosaic virus (CMV) is among the most important plant virus infections, inducing a variety of disease symptoms. However, the molecular mechanisms underlying plant responses to CMV infection remain poorly understood. In this study, we performed RNA sequencing analysis of tolerant (Taiyan8) and susceptible (NC82) tobacco cultivars on CMV-infected plants, using mock-inoculated plants as a control. The propagation of CMV in inoculated leaves did not show obvious difference between two cultivars, whereas virus accumulation in systemic leaves of Taiyan8 was smaller than those of NC82 at the same time point. We observed 765 and 1,011 differentially expressed genes (DEGs) in Taiyan8 and NC82, respectively, in CMV-inoculated leaves. DEGs related to reactive oxygen species, salicylic acid signal transduction, and plant-pathogen interaction were upregulated or downregulated in Taiyan8, which indicates that defense response pathways to CMV were activated in the tolerant cultivar. In addition, we identified several DEGs related to disease defense and stress resistance showing opposing expression patterns in the two cultivars. Our comparative transcriptome analysis will improve our understanding of the mechanisms of CMV tolerance in plants, and will be of great importance in the molecular breeding of CMV- tolerant genotypes.
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Affiliation(s)
- Dan Liu
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
| | - Qiang Zhao
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
| | - Yazeng Cheng
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
| | - Dandan Li
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
| | - Caihong Jiang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
| | - Lirui Cheng
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
| | - Yuanying Wang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China
| | - Aiguo Yang
- Tobacco Research Institute, Chinese Academy of Agricultural Sciences, Qingdao, 266101, China.
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12
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Gao S, Lu J, Cheng X, Gu Z, Liao Q, Du Z. Heterologous Replicase from Cucumoviruses can Replicate Viral RNAs, but is Defective in Transcribing Subgenomic RNA4A or Facilitating Viral Movement. Viruses 2018; 10:v10110590. [PMID: 30373277 PMCID: PMC6265798 DOI: 10.3390/v10110590] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Revised: 10/18/2018] [Accepted: 10/26/2018] [Indexed: 12/05/2022] Open
Abstract
Interspecific exchange of RNA1 or RNA2 between the cucumoviruses cucumber mosaic virus (CMV) and tomato aspermy virus (TAV) was reported to be non-viable in plants previously. Here we investigated viability of the reassortants between CMV and TAV in Nicotiana benthamiana plants by Agrobacterium-mediated viral inoculation. The reassortants were composed of CMV RNA1 and TAV RNA2 plus RNA3 replicated in the inoculated leaves, while they were defective in viral systemic movement at the early stage of infection. Interestingly, the reassortant containing TAV RNA1 and CMV RNA2 and RNA3 infected plants systemically, but produced RNA4A (the RNA2 subgenome) at an undetectable level. The defect in production of RNA4A was due to the 1a protein encoded by TAV RNA1, and partially restored by replacing the C-terminus (helicase domain) in TAV 1a with that of CMV 1a. Collectively, exchange of the replicase components between CMV and TAV was acceptable for viral replication, but was defective in either directing transcription of subgenomic RNA4A or facilitating viral long-distance movement. Our finding may shed some light on evolution of subgenomic RNA4A in the family Bromoviridae.
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Affiliation(s)
- Shuangyu Gao
- College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Jinda Lu
- College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Xiaodong Cheng
- College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Zhouhang Gu
- College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Qiansheng Liao
- College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China.
| | - Zhiyou Du
- College of Life Sciences, Zhejiang Sci-Tech University, Hangzhou 310018, China.
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13
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Salánki K, Gellért Á, Nemes K, Divéki Z, Balázs E. Molecular Modeling for Better Understanding of Cucumovirus Pathology. Adv Virus Res 2018; 102:59-88. [PMID: 30266176 DOI: 10.1016/bs.aivir.2018.06.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Cucumber mosaic virus (CMV) is a small RNA virus capable of infecting a wide variety of plant species. The high economic losses due to the CMV infection made this virus a relevant subject of scientific studies, which were further facilitated by the small size of the viral genome. Hence, CMV also became a model organism to investigate the molecular mechanism of pathogenesis. All viral functions are dependent on intra- and intermolecular interactions between nucleic acids and proteins of the virus and the host. This review summarizes the recent data on molecular determinants of such interactions. A particular emphasis is given to the results obtained by utilizing molecular-based planning and modeling techniques.
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Affiliation(s)
- Katalin Salánki
- MTA ATK, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ákos Gellért
- MTA ATK, Institute for Veterinary Medical Research, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary
| | - Katalin Nemes
- MTA ATK, Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary
| | - Zoltán Divéki
- MTA ATK, Agricultural Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary
| | - Ervin Balázs
- MTA ATK, Agricultural Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Budapest, Hungary.
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14
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Choi S, Lee JH, Kang WH, Kim J, Huy HN, Park SW, Son EH, Kwon JK, Kang BC. Identification of Cucumber mosaic resistance 2 ( cmr2) That Confers Resistance to a New Cucumber mosaic virus Isolate P1 (CMV-P1) in Pepper ( Capsicum spp.). FRONTIERS IN PLANT SCIENCE 2018; 9:1106. [PMID: 30186289 PMCID: PMC6110927 DOI: 10.3389/fpls.2018.01106] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2018] [Accepted: 07/09/2018] [Indexed: 05/09/2023]
Abstract
Cucumber mosaic virus (CMV) is one of the most devastating phytopathogens of Capsicum. The single dominant resistance gene, Cucumber mosaic resistant 1 (Cmr1), that confers resistance to the CMV isolate P0 has been overcome by a new isolate (CMV-P1) after being deployed in pepper (Capsicum annuum) breeding for over 20 years. A recently identified Indian C. annuum cultivar, "Lam32," displays resistance to CMV-P1. In this study, we show that the resistance in "Lam32" is controlled by a single recessive gene, CMV resistance gene 2 (cmr2). We found that cmr2 conferred resistance to CMV strains including CMV-Korean, CMV-Fny, and CMV-P1, indicating that cmr2 provides a broad-spectrum type of resistance. We utilized two molecular mapping approaches to determine the chromosomal location of cmr2. Bulked segregant analysis (BSA) using amplified fragment-length polymorphism (AFLP) (BSA-AFLP) revealed one marker, cmvAFLP, located 16 cM from cmr2. BSA using the Affymetrix pepper array (BSA-Affy) identified a single-nucleotide polymorphism (SNP) marker (Affy4) located 2.3 cM from cmr2 on chromosome 8. We further screened a pepper germplasm collection of 4,197 accessions for additional CMV-P1 resistance sources and found that some accessions contained equivalent levels of resistance to that of "Lam32." Inheritance and allelism tests demonstrated that all the resistance sources examined contained cmr2. Our result thus provide genetic and molecular evidence that cmr2 is a single recessive gene that confers to pepper an unprecedented resistance to the dangerous new isolate CMV-P1 that had overcome Cmr1.
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Affiliation(s)
- Seula Choi
- Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Joung-Ho Lee
- Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Won-Hee Kang
- Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Joonyup Kim
- Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Hoang N. Huy
- Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Sung-Woo Park
- Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Eun-Ho Son
- RDA-Genebank Information Center, Jeonju, South Korea
| | - Jin-Kyung Kwon
- Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
| | - Byoung-Cheorl Kang
- Department of Plant Science, Plant Genomics and Breeding Institute, Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul, South Korea
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15
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Chaturvedi S, Rao ALN. Riboproteomics: A versatile approach for the identification of host protein interaction network in plant pathogenic noncoding RNAs. PLoS One 2017; 12:e0186703. [PMID: 29073276 PMCID: PMC5658079 DOI: 10.1371/journal.pone.0186703] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 10/05/2017] [Indexed: 11/19/2022] Open
Abstract
Pathogenic or non-pathogenic small (17 to 30 nt) and long (>200 nt) non-coding RNAs (ncRNAs) have been implicated in the regulation of gene expression at transcriptional, post-transcriptional and epigenetic level by interacting with host proteins. However, lack of suitable experimental system precludes the identification and evaluation of the functional significance of host proteins interacting with ncRNAs. In this study, we present a first report on the application of riboproteomics to identify host proteins interacting with small, highly pathogenic, noncoding satellite RNA (sat-RNA) associated with Cucumber mosaic virus, the helper virus (HV). RNA affinity beads containing sat-RNA transcripts of (+) or (-)-sense covalently coupled to cyanogen bromide activated sepharose beads were incubated with total protein extracts from either healthy or HV-infected Nicotiana benthamiana leaves. RNA-protein complexes bound to the beads were eluted and subjected to MudPIT analysis. Bioinformatics programs PANTHER classification and WoLF-PSORT were used to further classify the identified host proteins in each case based on their functionality and subcellular distribution. Finally, we observed that the host protein network interacting with plus and minus-strand transcripts of sat-RNA, in the presence or absence of HV is distinct, and the global interactome of host proteins interacting with satRNA in either of the orientations is very different.
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Affiliation(s)
- Sonali Chaturvedi
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, United States of America
| | - A. L. N. Rao
- Department of Microbiology & Plant Pathology, University of California, Riverside, California, United States of America
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16
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Wang H, Seo JK, Gao S, Cui X, Jin H. Silencing of AtRAP, a target gene of a bacteria-induced small RNA, triggers antibacterial defense responses through activation of LSU2 and down-regulation of GLK1. THE NEW PHYTOLOGIST 2017; 215:1144-1155. [PMID: 28656601 PMCID: PMC5730055 DOI: 10.1111/nph.14654] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Accepted: 04/28/2017] [Indexed: 05/29/2023]
Abstract
Plants fine-tune their sophisticated immunity systems in response to pathogen infections. We previously showed that AtlsiRNA-1, a bacteria-induced plant endogenous small interfering RNA, silences the AtRAP gene, which encodes a putative RNA binding protein. In this study, we demonstrate that AtRAP functions as a negative regulator in plant immunity by characterizing molecular and biological responses of the knockout mutant and overexpression lines of AtRAP upon bacterial infection. AtRAP is localized in chloroplasts and physically interacts with Low Sulfur Upregulated 2 (LSU2), which positively regulates plant defense. Our results suggest that AtRAP negatively regulates defense responses by suppressing LSU2 through physical interaction. We also detected downregulation of the transcription factor GOLDEN2-LIKE 1 (GLK1) in atrap-1 using microarray analysis. The glk1 glk2 double mutant showed enhanced resistance to Pseudomonas syringae pv. tomato, which is consistent with a previous study showing enhanced resistance of a glk1 glk2 double mutant to Hyaloperonospora arabidopsidis. Taken together, our data suggest that silencing of AtRAP by AtlsiRNA-1 upon bacterial infection triggers defense responses through regulation of LSU2 and GLK1.
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Affiliation(s)
- Huan Wang
- Department of Plant Pathology & Microbiology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, USA
| | - Jang-Kyun Seo
- Graduate School of International Agricultural Technology, Seoul National University, Gangwon-do 25354, Korea
| | - Shang Gao
- Department of Plant Pathology & Microbiology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, USA
| | - Xinping Cui
- Department of Statistics, University of California, Riverside, CA 92521-0122, USA
| | - Hailing Jin
- Department of Plant Pathology & Microbiology, Institute for Integrative Genome Biology, University of California, Riverside, CA 92521-0122, USA
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17
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Kwak HR, Lee YJ, Kim J, Kim MK, Kim JS, Choi HS, Seo JK. A determinant of disease symptom severity is located in RNA2 of broad bean wilt virus 2. Virus Res 2016; 211:25-8. [PMID: 26428303 DOI: 10.1016/j.virusres.2015.09.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 09/23/2015] [Accepted: 09/23/2015] [Indexed: 11/23/2022]
Abstract
Broad bean wilt virus 2 (BBWV2), which belongs to the genus Fabavirus, is a destructive pathogen of many economically important horticultural and ornamental crops. In this study, we constructed infectious full-length cDNA clones of two distinct isolates of BBWV2 under control of the cauliflower mosaic virus 35S promoter. BBWV2-PAP1 isolated from paprika (Capsicum annuum var. gulosum) induces severe disease symptoms in various pepper varieties, whereas BBWV2-RP1 isolated from red pepper (Capsicum annuum L.) causes mild symptoms. Agrobacterium-mediated inoculation of the infectious cDNA clones of BBWV2-PAP1 and RP1 resulted in the same symptoms as the original virus isolates. The infectious cDNA clones of BBWV2-PAP1 and RP1 were used to examine the symptoms induced by pseudorecombinants between the two isolates to localize in which of the two genomic RNAs are the symptom severity determinants in BBWV2. The pseudorecombinant of RP1-RNA1 and PAP1-RNA2 induced severe symptoms, similar to those caused by the parental isolate PAP1, whereas the pseudorecombinant of PAP1-RNA1 and RP1-RNA2 induced mild symptoms, similar to those caused by the parental isolate RP1. Our results suggest that BBWV2 RNA2 contains a symptom determinant(s) capable of enhancing symptom severity.
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Affiliation(s)
- Hae-Ryun Kwak
- Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Republic of Korea
| | - Ye-Ji Lee
- Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Republic of Korea
| | - Jaedeok Kim
- Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Republic of Korea
| | - Mi-Kyeong Kim
- Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Republic of Korea
| | - Jeong-Soo Kim
- Department of Plant Medicine, Andong National University, Andong 760-749, Republic of Korea
| | - Hong-Soo Choi
- Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Republic of Korea.
| | - Jang-Kyun Seo
- Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Republic of Korea.
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18
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Rao ALN, Chaturvedi S, Garmann RF. Integration of replication and assembly of infectious virions in plant RNA viruses. Curr Opin Virol 2014; 9:61-6. [DOI: 10.1016/j.coviro.2014.09.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/04/2014] [Accepted: 09/18/2014] [Indexed: 02/08/2023]
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19
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Chaturvedi S, Rao ALN. Live cell imaging of interactions between replicase and capsid protein of Brome mosaic virus using Bimolecular Fluorescence Complementation: implications for replication and genome packaging. Virology 2014; 464-465:67-75. [PMID: 25046269 DOI: 10.1016/j.virol.2014.06.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2014] [Revised: 04/22/2014] [Accepted: 06/22/2014] [Indexed: 10/25/2022]
Abstract
In Brome mosaic virus, it was hypothesized that a physical interaction between viral replicase and capsid protein (CP) is obligatory to confer genome packaging specificity. Here we tested this hypothesis by employing Bimolecular Fluorescent Complementation (BiFC) as a tool for evaluating protein-protein interactions in living cells. The efficacy of BiFC was validated by a known interaction between replicase protein 1a (p1a) and protein 2a (p2a) at the endoplasmic reticulum (ER) site of viral replication. Additionally, co-expression in planta of a bona fide pair of interacting protein partners of p1a and p2a had resulted in the assembly of a functional replicase. Subsequent BiFC assays in conjunction with mCherry labeled ER as a fluorescent cellular marker revealed that CP physically interacts with p2a, but not p1a, and this CP:p2a interaction occurs at the cytoplasmic phase of the ER. The significance of the CP:p2a interaction in BMV replication and genome packaging is discussed.
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Affiliation(s)
- Sonali Chaturvedi
- Department of Plant Pathology & Microbiology, University of California, Riverside, CA 92521-0122, USA
| | - A L N Rao
- Department of Plant Pathology & Microbiology, University of California, Riverside, CA 92521-0122, USA.
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20
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Phan MSV, Seo JK, Choi HS, Lee SH, Kim KH. Pseudorecombination between Two Distinct Strains of Cucumber mosaic virus Results in Enhancement of Symptom Severity. THE PLANT PATHOLOGY JOURNAL 2014; 30:316-22. [PMID: 25289019 PMCID: PMC4181118 DOI: 10.5423/ppj.nt.04.2014.0031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Accepted: 05/08/2014] [Indexed: 05/21/2023]
Abstract
Recently, a Cucumber mosaic virus (CMV) strain, named as CMV-209, was isolated from Glycine soja. In this study, symptom expression of CMV-209 was analyzed in detail in Nicotiana benthamiana by comparing with that of CMV-Fny, which is a representative strain of CMV. Using infectious cDNA clones of CMV strains 209 and Fny, symptom expression of various pseudorecombinants between these two strains were examined in the early and late infection stages. In the early infection stage, the pseudorecombinants containing Fny-RNA2 induced stunting and leaf distortion on the newly emerged leaves whereas the pseudorecombinants containing 209-RNA2 caused no obvious symptoms. In the late infection stage, the pseudorecombinants containing 209-RNA1 and Fny-RNA2 induced severe leaf distortion and stunting, while CMV-209 induced mild symptom and CMV-Fny caused typical mosaic, general stunting, and leaf distortion symptoms, indicating that RNA 2 encodes a symptom determinant(s) of CMV, which is capable of enhancing symptoms. Furthermore, our results support the possibility that natural recombination between compatible viruses can result in emergence of novel viruses causing severe damages in crop fields.
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Affiliation(s)
- Mi Sa Vo Phan
- Department of Agricultural Biotechnology and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Korea
| | - Jang-Kyun Seo
- Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Korea
| | - Hong-Soo Choi
- Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Korea
| | - Su-Heon Lee
- Department of Applied Biology, Kyungpook National University, Daegu 702-701, Korea
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
- Corresponding author. Phone) +82-2-880-4677, FAX) +82-2-873-2317 E-mail)
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21
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Phan MSV, Seo JK, Choi HS, Lee SH, Kim KH. Molecular and Biological Characterization of an Isolate of Cucumber mosaic virus from Glycine soja by Generating its Infectious Full-genome cDNA Clones. THE PLANT PATHOLOGY JOURNAL 2014; 30:159-67. [PMID: 25288998 PMCID: PMC4174851 DOI: 10.5423/ppj.oa.02.2014.0014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2014] [Revised: 03/17/2014] [Accepted: 03/20/2014] [Indexed: 05/16/2023]
Abstract
Molecular and biological characteristics of an isolate of Cucumber mosaic virus (CMV) from Glycine soja (wild soybean), named as CMV-209, was examined in this study. Comparison of nucleotide sequences and phylogenetic analyses of CMV-209 with the other CMV strains revealed that CMV-209 belonged to CMV subgroup I. However, CMV-209 showed some genetic distance from the CMV strains assigned to subgroup IA or subgroup IB. Infectious full-genome cDNA clones of CMV-209 were generated under the control of the Cauliflower mosaic virus 35S promoter. Infectivity of the CMV-209 clones was evaluated in Nicotiana benthamiana and various legume species. Our assays revealed that CMV-209 could systemically infect Glycine soja (wild soybean) and Pisum sativum (pea) as well as N. benthamiana, but not the other legume species.
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Affiliation(s)
- Mi Sa Vo Phan
- Department of Agricultural Biotechnology and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Korea
| | - Jang-Kyun Seo
- Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Korea
| | - Hong-Soo Choi
- Crop Protection Division, National Academy of Agricultural Science, Rural Development Administration, Suwon 441-707, Korea
| | - Su-Heon Lee
- Department of Applied Biology, Kyungpook National University, Daegu 702-701, Korea
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Korea
- Research Institute of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, Korea
- Corresponding author. Phone) +82-2-880-4677, FAX) +82-2-873-2317, E-mail)
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22
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Kang WH, Seo JK, Chung BN, Kim KH, Kang BC. Helicase domain encoded by Cucumber mosaic virus RNA1 determines systemic infection of Cmr1 in pepper. PLoS One 2012; 7:e43136. [PMID: 22905216 PMCID: PMC3419664 DOI: 10.1371/journal.pone.0043136] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2012] [Accepted: 07/17/2012] [Indexed: 11/24/2022] Open
Abstract
The Cmr1 gene in peppers confers resistance to Cucumber mosaic virus isolate-P0 (CMV-P0). Cmr1 restricts the systemic spread of CMV strain-Fny (CMV-Fny), whereas this gene cannot block the spread of CMV isolate-P1 (CMV-P1) to the upper leaves, resulting in systemic infection. To identify the virulence determinant of CMV-P1, six reassortant viruses and six chimeric viruses derived from CMV-Fny and CMV-P1 cDNA clones were used. Our results demonstrate that the C-terminus of the helicase domain encoded by CMV-P1 RNA1 determines susceptibility to systemic infection, and that the helicase domain contains six different amino acid substitutions between CMV-Fny and CMV-P1(.) To identify the key amino acids of the helicase domain determining systemic infection with CMV-P1, we then constructed amino acid substitution mutants. Of the mutants tested, amino acid residues at positions 865, 896, 957, and 980 in the 1a protein sequence of CMV-P1 affected the systemic infection. Virus localization studies with GFP-tagged CMV clones and in situ localization of virus RNA revealed that these four amino acid residues together form the movement determinant for CMV-P1 movement from the epidermal cell layer to mesophyll cell layers. Quantitative real-time PCR revealed that CMV-P1 and a chimeric virus with four amino acid residues of CMV-P1 accumulated more genomic RNA in inoculated leaves than did CMV-Fny, indicating that those four amino acids are also involved in virus replication. These results demonstrate that the C-terminal region of the helicase domain is responsible for systemic infection by controlling virus replication and cell-to-cell movement. Whereas four amino acids are responsible for acquiring virulence in CMV-Fny, six amino acid (positions at 865, 896, 901, 957, 980 and 993) substitutions in CMV-P1 were required for complete loss of virulence in 'Bukang'.
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Affiliation(s)
- Won-Hee Kang
- Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, Korea
| | - Jang-Kyun Seo
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Bong Nam Chung
- National Institute of Horticultural and Herbal Science, Rural Development Administration, Suwon, Korea
| | - Kook-Hyung Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Korea
| | - Byoung-Cheorl Kang
- Department of Plant Science, Plant Genomics and Breeding Institute, and Research Institute for Agriculture and Life Sciences, Seoul National University, Seoul, Korea
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23
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Seo JK, Kwon SJ, Rao ALN. Molecular dissection of Flock house virus protein B2 reveals that electrostatic interactions between N-terminal domains of B2 monomers are critical for dimerization. Virology 2012; 432:296-305. [PMID: 22721960 DOI: 10.1016/j.virol.2012.05.023] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 05/16/2012] [Accepted: 05/28/2012] [Indexed: 11/18/2022]
Abstract
Flock house virus (FHV) encodes a suppressor protein B2 to overcome antiviral RNA silencing during infection. Biochemical analyses have shown that a homodimer of B2 binds to double-stranded RNA to inhibit dicer-mediated cleavage of dsRNA and incorporation of small interfering RNAs into the RNA-induced silencing complex. In this study, using FHV-Nicotiana benthamiana system, we identified that the charged amino acids at the N-terminus of B2 are critical for dimerization. Interestingly, B2 mutants defective in dimerization exhibited enhanced silencing suppressor activity, Furthermore, we found that the C-terminal charged amino acids are dispensable for B2 dimerization and viral RNA silencing suppression but are critical for transgene silencing suppression. Additional yeast two hybrid assays revealed that dimerization of B2 is not essential for interacting with the RNA silencing machinery. Taken together, our data provide evidence that both monomeric and dimeric B2 proteins function in different modes to suppress RNA silencing.
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Affiliation(s)
- Jang-Kyun Seo
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA 92521-0122, USA
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24
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Seo JK, Kwon SJ, Rao ALN. A physical interaction between viral replicase and capsid protein is required for genome-packaging specificity in an RNA virus. J Virol 2012; 86:6210-21. [PMID: 22438552 PMCID: PMC3372179 DOI: 10.1128/jvi.07184-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 03/09/2012] [Indexed: 01/03/2023] Open
Abstract
Genome packaging is functionally coupled to replication in RNA viruses pathogenic to humans (Poliovirus), insects (Flock house virus [FHV]), and plants (Brome mosaic virus [BMV]). However, the underlying mechanism is not fully understood. We have observed previously that in FHV and BMV, unlike ectopically expressed capsid protein (CP), packaging specificity results from RNA encapsidation by CP that has been translated from mRNA produced from replicating genomic RNA. Consequently, we hypothesize that a physical interaction with replicase increases the CP specificity for packaging viral RNAs. We tested this hypothesis by evaluating the molecular interaction between replicase protein and CP using a FHV-Nicotiana benthamiana system. Bimolecular fluorescence complementation in conjunction with fluorescent cellular protein markers and coimmunoprecipitation assays demonstrated that FHV replicase (protein A) and CP physically interact at the mitochondrial site of replication and that this interaction requires the N-proximal region from either amino acids 1 to 31 or amino acids 32 to 50 of the CP. In contrast to the mitochondrial localization of CP derived from FHV replication, ectopic expression displayed a characteristic punctate pattern on the endoplasmic reticulum (ER). This pattern was altered to relocalize the CP throughout the cytoplasm when the C-proximal hydrophobic domain was deleted. Analysis of the packaging phenotypes of the CP mutants defective either in protein A-CP interactions or ER localization suggested that synchronization between protein A-CP interaction and its subcellular localization is imperative to confer packaging specificity.
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Affiliation(s)
- Jang-Kyun Seo
- Department of Plant Pathology and Microbiology, University of California, Riverside, California, USA
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25
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Kwon SJ, Rao ALN. Emergence of distinct brome mosaic virus recombinants is determined by the polarity of the inoculum RNA. J Virol 2012; 86:5204-20. [PMID: 22357282 PMCID: PMC3347362 DOI: 10.1128/jvi.00351-12] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2012] [Accepted: 02/14/2012] [Indexed: 12/22/2022] Open
Abstract
Despite overwhelming interest in the impact exerted by recombination during evolution of RNA viruses, the relative contribution of the polarity of inoculum templates remains poorly understood. Here, by agroinfiltrating Nicotiana benthamiana leaves, we show that brome mosaic virus (BMV) replicase is competent to initiate positive-strand [(+)-strand] synthesis on an ectopically expressed RNA3 negative strand [(-) strand] and faithfully complete the replication cycle. Consequently, we sought to examine the role of RNA polarity in BMV recombination by expressing a series of replication-defective mutants of BMV RNA3 in (+) or (-) polarity. Temporal analysis of progeny sequences revealed that the genetic makeup of the primary recombinant pool is determined by the polarity of the inoculum template. When the polarity of the inoculum template was (+), the recombinant pool that accumulated during early phases of replication was a mixture of nonhomologous recombinants. These are longer than the inoculum template length, and a nascent 3' untranslated region (UTR) of wild-type (WT) RNA1 or RNA2 was added to the input mutant RNA3 3' UTR due to end-to-end template switching by BMV replicase during (-)-strand synthesis. In contrast, when the polarity of the inoculum was (-), the progeny contained a pool of native-length homologous recombinants generated by template switching of BMV replicase with a nascent UTR from WT RNA1 or RNA2 during (+)-strand synthesis. Repair of a point mutation caused by polymerase error occurred only when the polarity of the inoculum template was (+). These results contribute to the explanation of the functional role of RNA polarity in recombination mediated by copy choice mechanisms.
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Affiliation(s)
- Sun-Jung Kwon
- Department of Plant Pathology & Microbiology, University of California, Riverside, California, USA
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Mochizuki T, Ohki ST. Cucumber mosaic virus: viral genes as virulence determinants. MOLECULAR PLANT PATHOLOGY 2012; 13:217-25. [PMID: 21980997 PMCID: PMC6638793 DOI: 10.1111/j.1364-3703.2011.00749.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
TAXONOMIC RELATIONSHIPS Cucumber mosaic virus (CMV) is the type species of the genus Cucumovirus in the family Bromoviridae, which also encompasses the Peanut stunt virus (PSV) and the Tomato aspermy virus (TAV). Nucleotide sequence similarity among these three cucumoviruses is 60%-65%. CMV strains are divided into three subgroups, IA, IB and II, based on the sequence of the 5' untranslated region of the genomic RNA 3. Overall nucleotide sequence similarity among CMV strains is approximately 70%-98%. GEOGRAPHICAL DISTRIBUTION, HOST RANGE AND SYMPTOMATOLOGY: CMV is distributed worldwide, primarily in temperate to tropical climate zones. CMV infects more than 1200 species of 100 plant families, including monocot and dicot plants. Symptoms caused by CMV infection vary with the host species and/or CMV strain, and include mosaic, stunt, chlorosis, dwarfing, leaf malformation and systemic necrosis. CMV disease is spread primarily by aphid transmission in a nonpersistent manner. PHYSICAL PROPERTIES In tobacco sap, the thermal inactivation point of the viral infectivity is approximately 70 °C (10 min), the dilution end-point is approximately 10(-4) and viral infectivity is lost after a few days of exposure to 20 °C. Viral infectivity can be retained in freeze-dried tissues and in the form of virions purified using 5 mm sodium borate, 0.5 mm ethylenediaminetetraacetic acid and 50% glycerol (pH 9.0) at -20 °C. CMV particles are isometric, approximately 28-30 nm in diameter and are composed of 180 capsid subunits arranged in pentamer-hexamer clusters with T= 3 symmetry. The sedimentation coefficient (s(20) ,(w) ) is c. 98 S and the particle weight is (5.8-6.7) × 10(6) Da. The virions contain 18% RNA. The RNA-protein interactions that stabilize the CMV virions are readily disrupted by sodium dodecylsulphate or neutral chloride salts. GENOMIC PROPERTIES: The genomic RNAs are single-stranded messenger sense RNAs with 5' cap and 3' tRNA-like structures containing at least five open reading frames. The viral RNA consists of three genomic RNAs, RNA 1 (c. 3.3 kb), RNA 2 (c. 3.0 kb) and RNA 3 (c. 2.2 kb), and two subgenomic RNAs, RNA 4 (c. 1.0 kb) and RNA 4A (c. 0.7 kb). The 3' untranslated regions are conserved across all viral RNAs. CMV is often accompanied by satellite, noncoding, small, linear RNA that is nonhomologous to the helper CMV.
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Affiliation(s)
- Tomofumi Mochizuki
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka, Japan.
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RNA synthesis by the brome mosaic virus RNA-dependent RNA polymerase in human cells reveals requirements for de novo initiation and protein-protein interaction. J Virol 2012; 86:4317-27. [PMID: 22318148 DOI: 10.1128/jvi.00069-12] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Brome mosaic virus (BMV) is a model positive-strand RNA virus whose replication has been studied in a number of surrogate hosts. In transiently transfected human cells, the BMV polymerase 2a activated signaling by the innate immune receptor RIG-I, which recognizes de novo-initiated non-self-RNAs. Active-site mutations in 2a abolished RIG-I activation, and coexpression of the BMV 1a protein stimulated 2a activity. Mutations previously shown to abolish 1a and 2a interaction prevented the 1a-dependent enhancement of 2a activity. New insights into 1a-2a interaction include the findings that helicase active site of 1a is required to enhance 2a polymerase activity and that negatively charged amino acid residues between positions 110 and 120 of 2a contribute to interaction with the 1a helicase-like domain but not to the intrinsic polymerase activity. Confocal fluorescence microscopy revealed that the BMV 1a and 2a colocalized to perinuclear region in human cells. However, no perinuclear spherule-like structures were detected in human cells by immunoelectron microscopy. Sequencing of the RNAs coimmunoprecipitated with RIG-I revealed that the 2a-synthesized short RNAs are derived from the message used to translate 2a. That is, 2a exhibits a strong cis preference for BMV RNA2. Strikingly, the 2a RNA products had initiation sequences (5'-GUAAA-3') identical to those from the 5' sequence of the BMV genomic RNA2 and RNA3. These results show that the BMV 2a polymerase does not require other BMV proteins to initiate RNA synthesis but that the 1a helicase domain, and likely helicase activity, can affect RNA synthesis by 2a.
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Abstract
Cucumber mosaic virus (CMV) is an important virus because of its agricultural impact in the Mediterranean Basin and worldwide, and also as a model for understanding plant-virus interactions. This review focuses on those areas where most progress has been made over the past decade in our understanding of CMV. Clearly, a deep understanding of the role of the recently described CMV 2b gene in suppression of host RNA silencing and viral virulence is the most important discovery. These findings have had an impact well beyond the virus itself, as the 2b gene is an important tool in the studies of eukaryotic gene regulation. Protein 2b was shown to be involved in most of the steps of the virus cycle and to interfere with several basal host defenses. Progress has also been made concerning the mechanisms of virus replication and movement. However, only a few host proteins that interact with viral proteins have been identified, making this an area of research where major efforts are still needed. Another area where major advances have been made is CMV population genetics, where contrasting results were obtained. On the one hand, CMV was shown to be prone to recombination and to show high genetic diversity based on sequence data of different isolates. On the other hand, populations did not exhibit high genetic variability either within plants, or even in a field and the nearby wild plants. The situation was partially clarified with the finding that severe bottlenecks occur during both virus movement within a plant and transmission between plants. Finally, novel studies were undertaken to elucidate mechanisms leading to selection in virus population, according to the host or its environment, opening a new research area in plant-virus coevolution.
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Choi SK, Yoon JY, Canto T, Palukaitis P. Replication of cucumber mosaic virus RNA 1 in cis requires functional helicase-like motifs of the 1a protein. Virus Res 2011; 158:271-6. [PMID: 21402113 DOI: 10.1016/j.virusres.2011.03.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2010] [Revised: 03/04/2011] [Accepted: 03/05/2011] [Indexed: 11/26/2022]
Abstract
The cucumber mosaic virus (CMV) encoded 1a protein contains an NTPase/helicase-like domain. To investigate whether various helicase motifs were required for efficient replication and to establish whether CMV RNA 1 could be replicated efficiently in cis, we constructed deletion mutations in helicase motifs I, III and VI and analyzed their effects on CMV RNA replication in tobacco. CMV replication was not detectable for any of the three helicase mutants, indicating that the helicase domain is crucial for efficient CMV replication. Both the wild-type and mutant 1a proteins could be detected at similar levels after transient expression in infiltrated tissues, indicating that the helicase-motif mutations did not affect the stability of the proteins. Co-inoculation tests with various mutant combinations did not result in complementation. In protoplasts derived from CMV RNA 1-transgenic tobacco, which supported replication of CMV RNAs 2 and 3, the RNA 1 helicase mutants were not replicated detectably in trans, but also did not interfere with the replication of the genomic RNAs, indicating that the conserved helicase motifs of the 1a protein are required in cis for the effective accumulation of RNA 1.
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Affiliation(s)
- Seung Kook Choi
- Institute of Natural Science, Myong-Ji University, Yong-In 449-728, South Korea
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30
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Zhang X, Li H, Zhang J, Zhang C, Gong P, Ziaf K, Xiao F, Ye Z. Expression of artificial microRNAs in tomato confers efficient and stable virus resistance in a cell-autonomous manner. Transgenic Res 2010; 20:569-81. [PMID: 20835923 DOI: 10.1007/s11248-010-9440-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2010] [Accepted: 08/29/2010] [Indexed: 12/26/2022]
Abstract
Expression of artificial microRNAs (amiRNAs) in plants can target and degrade the invading viral RNA, consequently conferring virus resistance. Two amiRNAs, targeting the coding sequence shared by the 2a and 2b genes and the highly conserved 3' untranslated region (UTR) of Cucumber mosaic virus (CMV), respectively, were generated and introduced into the susceptible tomato. The transgenic tomato plants expressing amiRNAs displayed effective resistance to CMV infection and CMV mixed with non-targeted viruses, including tobacco mosaic virus and tomato yellow leaf curl virus. A series of grafting assays indicate scions originated from the transgenic tomato plant maintain stable resistance to CMV infection after grafted onto a CMV-infected rootstock. However, the grafting assay also suggests that the amiRNA-mediated resistance acts in a cell-autonomous manner and the amiRNA signal cannot be transmitted over long distances through the vascular system. Moreover, transgenic plants expressing amiRNA targeting the 2a and 2b viral genes displayed slightly more effective to repress CMV RNA accumulation than transgenic plants expressing amiRNA targeting the 3' UTR of viral genome did. Our work provides new evidence of the use of amiRNAs as an effective approach to engineer viral resistance in the tomato and possibly in other crops.
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Affiliation(s)
- Xiaohui Zhang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
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Camborde L, Planchais S, Tournier V, Jakubiec A, Drugeon G, Lacassagne E, Pflieger S, Chenon M, Jupin I. The ubiquitin-proteasome system regulates the accumulation of Turnip yellow mosaic virus RNA-dependent RNA polymerase during viral infection. THE PLANT CELL 2010; 22:3142-52. [PMID: 20823192 PMCID: PMC2965540 DOI: 10.1105/tpc.109.072090] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/11/2009] [Revised: 08/01/2010] [Accepted: 08/22/2010] [Indexed: 05/19/2023]
Abstract
Replication of positive-strand RNA viruses, the largest group of plant viruses, is initiated by viral RNA-dependent RNA polymerase (RdRp). Given its essential function in viral replication, understanding the regulation of RdRp is of great importance. Here, we show that Turnip yellow mosaic virus (TYMV) RdRp (termed 66K) is degraded by the proteasome at late time points during viral infection and that the accumulation level of 66K affects viral RNA replication in infected Arabidopsis thaliana cells. We mapped the cis-determinants responsible for 66K degradation within its N-terminal noncatalytic domain, but we conclude that 66K is not a natural N-end rule substrate. Instead, we show that a proposed PEST sequence within 66K functions as a transferable degradation motif. In addition, several Lys residues that constitute target sites for ubiquitylation were mapped; mutation of these Lys residues leads to stabilization of 66K. Altogether, these results demonstrate that TYMV RdRp is a target of the ubiquitin-proteasome system in plant cells and support the idea that proteasomal degradation may constitute yet another fundamental level of regulation of viral replication.
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Seo JK, Kang SH, Seo BY, Jung JK, Kim KH. Mutational analysis of interaction between coat protein and helper component-proteinase of Soybean mosaic virus involved in aphid transmission. MOLECULAR PLANT PATHOLOGY 2010; 11:265-76. [PMID: 20447275 PMCID: PMC6640531 DOI: 10.1111/j.1364-3703.2009.00603.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Soybean mosaic virus (SMV), a member of the genus Potyvirus, is transmitted by aphids in a non-persistent manner. It has been well documented that the helper component-proteinase (HC-Pro) plays a role as a 'bridge' between virion particles and aphid stylets in the aphid transmission of potyviruses. Several motifs, including the KITC and PTK motifs on HC-Pro and the DAG motif on the coat protein (CP), have been found to be involved in aphid transmission. Previously, we have shown strong interaction between SMV CP and HC-Pro in a yeast two-hybrid system (YTHS). In this report, we further analysed this CP-HC-Pro interaction based on YTHS and an in vivo binding assay to identify crucial amino acid residues for this interaction. Through this genetic approach, we identified two additional amino acid residues (H256 on CP and R455 on HC-Pro), as well as G12 on the DAG motif, crucial for the CP-HC-Pro interaction. We introduced mutations into the identified residues using an SMV infectious clone and showed that these mutations affected the efficiency of aphid transmission of SMV. We also investigated the involvement of the PTK and DAG motifs in the CP-HC-Pro interaction and aphid transmission of SMV. Our results support the concept that physical interaction between CP and HC-Pro is important for potyviral aphid transmission. Based on the combination of our current results with previous findings, the possibility that aphid transmission may be regulated by more complex molecular interactions than the simple involvement of HC-Pro as a bridge is discussed.
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Affiliation(s)
- Jang-Kyun Seo
- Department of Agricultural Biotechnology and Center for Fungal Pathogenesis, College of Agriculture and Life Sciences, Seoul National University, Seoul 151-921, South Korea
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Park MR, Park SH, Cho SY, Kim KH. Nicotiana benthamiana protein, NbPCIP1, interacting with Potato virus X coat protein plays a role as susceptible factor for viral infection. Virology 2009; 386:257-69. [PMID: 19215953 DOI: 10.1016/j.virol.2008.12.044] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2008] [Revised: 11/01/2008] [Accepted: 12/31/2008] [Indexed: 11/24/2022]
Abstract
The interactions of viral coat protein (CP) and host factors play an important role in viral replication and/or host defense mechanism. In this study, we constructed Nicotiana benthamiana cDNA library to find host factors interacting with Potato virus X (PVX) CP. Using yeast two-hybrid assay, we screened 3.3 x 10(6) independent yeast transformants from N. benthamiana cDNA library and identified six positive clones. One positive clone, named PVX CP-interacting protein 1 (NbPCIP1), is a plant-specific protein with homologue in N. tabacum (GenBank accession no. AB04049). We confirmed the PVX CP-NbPCIP1 interaction using yeast-two hybrid assay in yeast, protein-protein binding assay in vitro, and bimolecular fluorescent complementation assay in planta. Quantitative real-time RT-PCR analysis showed that the mRNA level of NbPCIP1 increased in PVX-infected N. benthamiana plants as compared to that of healthy plants. The green fluorescent protein (sGFP)-fused NbPCIP1 (NbPCIP1-sGFP) was localized in ER or ER-associated granular-like structure of cells. When we co-express NbPCIP1-sGFP and red fluorescent protein (RFP)-fused PVX CP (PVX CP-RFP), which were introduced by transiently expressing these proteins in N. benthamiana protoplasts and epidermal cells, however, we observed the co-localization of these proteins in the inclusion body-like complex in areas surrounding nucleus. Transient over-expression and transgene silencing of NbPCIP1 assay analysis indicated that NbPCIP1 plays a critical role in viral replication during PVX infection in host plant.
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Affiliation(s)
- Mi-Ri Park
- Department of Agricultural Biotechnology and Plant Genomics and Breeding Institute, Seoul National University, Seoul 151-921, Republic of Korea
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