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Lee SC, Liou MR, Hsu YH, Wang IN, Lin NS. Trade-off between local replication and long-distance dissemination during experimental evolution of a satellite RNA. Front Microbiol 2023; 14:1139447. [PMID: 37601360 PMCID: PMC10436602 DOI: 10.3389/fmicb.2023.1139447] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2023] [Accepted: 07/19/2023] [Indexed: 08/22/2023] Open
Abstract
Satellite RNAs (satRNAs) are molecular parasites that depend on their non-homologous helper viruses (HVs) for essential biological functions. While there are multiple molecular and phylogenetic studies on satRNAs, there is no experimental evolution study on how satRNAs may evolve in common infection conditions. In this study, we serially passaged the Bamboo mosaic virus (BaMV) associated-satRNA (satBaMV) under conditions in which satBaMV either coinfects an uninfected host plant, Nicotiana benthamiana, with BaMV or superinfects a transgenic N. benthamiana expressing the full-length BaMV genome. Single-nucleotide polymorphisms (SNPs) of satBaMV populations were analyzed by deep sequencing. Forty-eight SNPs were identified across four different experimental treatments. Most SNPs are treatment-specific, and some are also ephemeral. However, mutations at positions 30, 34, 63, and 82, all located at the 5' untranslated region (UTR), are universal in all treatments. These universal SNPs are configured into several haplotypes and follow different population dynamics. We constructed isogenic satBaMV strains only differing at positions 30 and 82 and conducted competition experiments in protoplasts and host plants. We found that the haplotype that reached high frequency in protoplasts and inoculation leaves also exhibited poor dissemination to systemic leaves and vice versa, thus suggesting an apparent trade-off between local replication and long-distance dissemination. We posit that the trade-off is likely caused by antagonistic pleiotropy at the 5' UTR. Our findings revealed a hitherto under-explored connection between satRNA genome replication and movement within a host plant. The significance of such a connection during satRNA evolution warrants a more thorough investigation.
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Affiliation(s)
- Shu-Chuan Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Ming-Ru Liou
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Ing-Nang Wang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
- Department of Biological Sciences, University at Albany, Albany, NY, United States
| | - Na-Sheng Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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2
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Badar U, Venkataraman S, AbouHaidar M, Hefferon K. Molecular interactions of plant viral satellites. Virus Genes 2020; 57:1-22. [PMID: 33226576 DOI: 10.1007/s11262-020-01806-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 10/24/2020] [Indexed: 12/18/2022]
Abstract
Plant viral satellites fall under the category of subviral agents. Their genomes are composed of small RNA or DNA molecules a few hundred nucleotides in length and contain an assortment of highly complex and overlapping functions. Each lacks the ability to either replicate or undergo encapsidation or both in the absence of a helper virus (HV). As the number of known satellites increases steadily, our knowledge regarding their sequence conservation strategies, means of replication and specific interactions with host and helper viruses is improving. This review demonstrates that the molecular interactions of these satellites are unique and highly complex, largely influenced by the highly specific host plants and helper viruses that they associate with. Circularized forms of single-stranded RNA are of particular interest, as they have recently been found to play a variety of novel cellular functions. Linear forms of satRNA are also of great significance as they may complement the helper virus genome in exacerbating symptoms, or in certain instances, actively compete against it, thus reducing symptom severity. This review serves to describe the current literature with respect to these molecular mechanisms in detail as well as to discuss recent insights into this emerging field in terms of evolution, classification and symptom development. The review concludes with a discussion of future steps in plant viral satellite research and development.
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Affiliation(s)
- Uzma Badar
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | | | - Mounir AbouHaidar
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada
| | - Kathleen Hefferon
- Department of Cell and Systems Biology, University of Toronto, Toronto, ON, Canada.
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3
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Lee CC, Wang JW, Leu WM, Huang YT, Huang YW, Hsu YH, Meng M. Proliferating Cell Nuclear Antigen Suppresses RNA Replication of Bamboo Mosaic Virus through an Interaction with the Viral Genome. J Virol 2019; 93:e00961-19. [PMID: 31511381 PMCID: PMC6819918 DOI: 10.1128/jvi.00961-19] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Accepted: 08/30/2019] [Indexed: 11/20/2022] Open
Abstract
Bamboo mosaic virus (BaMV), a member of the Potexvirus genus, has a monopartite positive-strand RNA genome on which five open reading frames (ORFs) are organized. ORF1 encodes a 155-kDa nonstructural protein (REPBaMV) that plays a core function in replication/transcription of the viral genome. To find out cellular factors modulating the replication efficiency of BaMV, a putative REPBaMV-associated protein complex from Nicotiana benthamiana leaf was isolated on an SDS-PAGE gel, and a few proteins preferentially associated with REPBaMV were identified by tandem mass spectrometry. Among them, proliferating cell nuclear antigen (PCNA) was particularly noted. Overexpression of PCNA strongly suppressed the accumulation of BaMV coat protein and RNAs in leaf protoplasts. In addition, PCNA exhibited an inhibitory effect on BaMV polymerase activity. A pulldown assay confirmed a binding capability of PCNA toward BaMV genomic RNA. Mutations at D41 or F114 residues, which are critical for PCNA to function in nuclear DNA replication and repair, disabled PCNA from binding BaMV genomic RNA as well as suppressing BaMV replication. This suggests that PCNA bound to the viral RNA may interfere with the formation of a potent replication complex or block the replication process. Interestingly, BaMV is almost invisible in the newly emerging leaves where PCNA is actively expressed. Accordingly, PCNA is probably one of the factors restricting the proliferation of BaMV in young leaves. Foxtail mosaic virus and Potato virus X were also suppressed by PCNA in the protoplast experiment, suggesting a general inhibitory effect of PCNA on the replication of potexviruses.IMPORTANCE Knowing the dynamic interplay between plant RNA viruses and their host is a basic step toward first understanding how the viruses survive the plant defense mechanisms and second gaining knowledge of pathogenic control in the field. This study found that plant proliferating cell nuclear antigen (PCNA) imposes a strong inhibition on the replication of several potexviruses, including Bamboo mosaic virus, Foxtail mosaic virus, and Potato virus X Based on the tests on Bamboo mosaic virus, PCNA is able to bind the viral genomic RNA, and this binding is a prerequisite for the protein to suppress the virus replication. This study also suggests that PCNA plays an important role in restricting the proliferation of potexviruses in the rapidly dividing tissues of plants.
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Affiliation(s)
- Cheng-Cheng Lee
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Jhih-Wei Wang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Wei-Ming Leu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Yu-Ting Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Ying-Wen Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Menghsiao Meng
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
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4
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Alvarez-Quinto RA, Cornejo-Franco JF, Quito-Avila DF. Characterization of a not so new potexvirus from babaco (Vasconcellea x heilbornii). PLoS One 2017; 12:e0189519. [PMID: 29244846 PMCID: PMC5731686 DOI: 10.1371/journal.pone.0189519] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 11/28/2017] [Indexed: 11/19/2022] Open
Abstract
A new member of the genus Potexvirus was fully sequenced and characterized. The virus was isolated from babaco (Vasconcellea x heilbornii), a natural hybrid native to Ecuador. The virus contains a 6,692 nt long genome organized in five open reading frames in an arrangement typical of other potexviruses. Sequence comparisons revealed close relatedness with Papaya mosaic virus (PapMV), Alternathera mosaic virus (AltMV) and Senna mosaic virus (SenMV), exhibiting nucleotide identities up to 67% for the polymerase (Pol) and 68% for the coat protein (CP), with deduced amino acid identities of 70% and 72% for the Pol and CP, respectively. The presence of an AlkB domain, in the polymerase region, was observed. Terminal nucleotide sequences were conserved across potexviruses with characteristic motifs and predicted secondary structures at the 3' UTR. Although serologically undistinguishable from PapMV and AltMV, the new virus showed differences in host range and symptom induction. The name babaco mosaic virus is proposed for this newly characterized Potexvirus. The complete genome sequence of the new virus has been deposited in NCBI GenBank under accession number MF978248.
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Affiliation(s)
- Robert A. Alvarez-Quinto
- Centro de Investigaciones Biotecnológicas del Ecuador, CIBE, Escuela Superior Politécnica del Litoral, ESPOL, Guayaquil, Ecuador
| | - Juan F. Cornejo-Franco
- Facultad de Ciencias de la Vida, Escuela Superior Politécnica del Litoral, ESPOL, Guayaquil, Ecuador
| | - Diego F. Quito-Avila
- Centro de Investigaciones Biotecnológicas del Ecuador, CIBE, Escuela Superior Politécnica del Litoral, ESPOL, Guayaquil, Ecuador
- Facultad de Ciencias de la Vida, Escuela Superior Politécnica del Litoral, ESPOL, Guayaquil, Ecuador
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5
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Lin KY, Lin NS. Interfering Satellite RNAs of Bamboo mosaic virus. Front Microbiol 2017; 8:787. [PMID: 28522996 PMCID: PMC5415622 DOI: 10.3389/fmicb.2017.00787] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 04/18/2017] [Indexed: 11/13/2022] Open
Abstract
Satellite RNAs (satRNAs) are sub-viral agents that may interact with their cognate helper virus (HV) and host plant synergistically and/or antagonistically. SatRNAs totally depend on the HV for replication, so satRNAs and HV usually evolve similar secondary or tertiary RNA structures that are recognized by a replication complex, although satRNAs and HV do not share an appreciable sequence homology. The satRNAs of Bamboo mosaic virus (satBaMV), the only satRNAs of the genus Potexvirus, have become one of the models of how satRNAs can modulate HV replication and virus-induced symptoms. In this review, we summarize the molecular mechanisms underlying the interaction of interfering satBaMV and BaMV. Like other satRNAs, satBaMV mimics the secondary structures of 5'- and 3'-untranslated regions (UTRs) of BaMV as a molecular pretender. However, a conserved apical hairpin stem loop (AHSL) in the 5'-UTR of satBaMV was found as the key determinant for downregulating BaMV replication. In particular, two unique nucleotides (C60 and C83) in the AHSL of satBaMVs determine the satBaMV interference ability by competing for the replication machinery. Thus, transgenic plants expressing interfering satBaMV could confer resistance to BaMV, and interfering satBaMV could be used as biological-control agent. Unlike two major anti-viral mechanisms, RNA silencing and salicylic acid-mediated immunity, our findings in plants by in vivo competition assay and RNA deep sequencing suggested replication competition is involved in this transgenic satBaMV-mediated BaMV interference. We propose how a single nucleotide of satBaMV can make a great change in BaMV pathogenicity and the underlying mechanism.
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Affiliation(s)
- Kuan-Yu Lin
- Institute of Plant and Microbial Biology, Academia SinicaTaipei, Taiwan
| | - Na-Sheng Lin
- Institute of Plant and Microbial Biology, Academia SinicaTaipei, Taiwan
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6
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Huang YP, Chen IH, Tsai CH. Host Factors in the Infection Cycle of Bamboo mosaic virus. Front Microbiol 2017; 8:437. [PMID: 28360904 PMCID: PMC5350103 DOI: 10.3389/fmicb.2017.00437] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 03/02/2017] [Indexed: 12/02/2022] Open
Abstract
To complete the infection cycle efficiently, the virus must hijack the host systems in order to benefit for all the steps and has to face all the defense mechanisms from the host. This review involves a discussion of how these positive and negative factors regulate the viral RNA accumulation identified for the Bamboo mosaic virus (BaMV), a single-stranded RNA virus. The genome of BaMV is approximately 6.4 kb in length, encoding five functional polypeptides. To reveal the host factors involved in the infection cycle of BaMV, a few different approaches were taken to screen the candidates. One of the approaches is isolating the viral replicase-associated proteins by co-immunoprecipitation with the transiently expressed tagged viral replicase in plants. Another approach is using the cDNA-amplified fragment length polymorphism technique to screen the differentially expressed genes derived from N. benthamiana plants after infection. The candidates are examined by knocking down the expression in plants using the Tobacco rattle virus-based virus-induced gene silencing technique following BaMV inoculation. The positive or negative regulators could be described as reducing or enhancing the accumulation of BaMV in plants when the expression levels of these proteins are knocked down. The possible roles of these host factors acting on the accumulation of BaMV will be discussed.
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Affiliation(s)
- Ying-Ping Huang
- Graduate Institute of Biotechnology, National Chung Hsing University Taichung, Taiwan
| | - I-Hsuan Chen
- Graduate Institute of Biotechnology, National Chung Hsing University Taichung, Taiwan
| | - Ching-Hsiu Tsai
- Graduate Institute of Biotechnology, National Chung Hsing University Taichung, Taiwan
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7
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Ashton P, Wu B, D'Angelo J, Grigull J, White KA. Biologically-supported structural model for a viral satellite RNA. Nucleic Acids Res 2015; 43:9965-77. [PMID: 26384416 PMCID: PMC4787747 DOI: 10.1093/nar/gkv917] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 09/04/2015] [Indexed: 01/05/2023] Open
Abstract
Satellite RNAs (satRNAs) are a class of small parasitic RNA replicon that associate with different viruses, including plus-strand RNA viruses. Because satRNAs do not encode a polymerase or capsid subunit, they rely on a companion virus to provide these proteins for their RNA replication and packaging. SatRNAs recruit these and other required factors via their RNA sequences and structures. Here, through a combination of chemical probing analysis of RNA structure, phylogenetic structural comparisons, and viability assays of satRNA mutants in infected cells, the biological importance of a deduced higher-order structure for a 619 nt long tombusvirus satRNA was assessed. Functionally-relevant secondary and tertiary RNA structures were identified throughout the length of the satRNA. Notably, a 3′-terminal segment was found to adopt two mutually-exclusive RNA secondary structures, both of which were required for efficient satRNA accumulation. Accordingly, these alternative conformations likely function as a type of RNA switch. The RNA switch was also found to engage in a required long-range kissing-loop interaction with an upstream sequence. Collectively, these results establish a high level of conformational complexity within this small parasitic RNA and provide a valuable structural framework for detailed mechanistic studies.
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Affiliation(s)
- Peter Ashton
- Department of Biology, York University, Toronto, Ontario, M3J 1P3 Canada
| | - Baodong Wu
- Department of Biology, York University, Toronto, Ontario, M3J 1P3 Canada
| | - Jessica D'Angelo
- Department of Biology, York University, Toronto, Ontario, M3J 1P3 Canada
| | - Jörg Grigull
- Department of Mathematics and Statistics, York University, Toronto, Ontario, M3J 1P3 Canada
| | - K Andrew White
- Department of Biology, York University, Toronto, Ontario, M3J 1P3 Canada
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8
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Liu L, Wang Q, Cheng J, Fu Y, Jiang D, Xie J. Molecular characterization of a bipartite double-stranded RNA virus and its satellite-like RNA co-infecting the phytopathogenic fungus Sclerotinia sclerotiorum. Front Microbiol 2015; 6:406. [PMID: 25999933 PMCID: PMC4422086 DOI: 10.3389/fmicb.2015.00406] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2015] [Accepted: 04/19/2015] [Indexed: 11/13/2022] Open
Abstract
A variety of mycoviruses have been found in Sclerotinia sclerotiorum. In this study, we report a novel mycovirus S. sclerotiorum botybirnavirus 1 (SsBRV1) that was originally isolated from the hypovirulent strain SCH941 of S. sclerotiorum. SsBRV1 has rigid spherical virions that are ∼38 nm in diameter, and three double-stranded RNA (dsRNA) segments (dsRNA1, 2, and 3 with lengths of 6.4, 6.0, and 1.7 kbp, respectively) were packaged in the virions. dsRNA1 encodes a cap-pol fusion protein, and dsRNA2 encodes a polyprotein with unknown functions but contributes to the formation of virus particles. The dsRNA3 is dispensable and may be a satellite-like RNA of SsBRV1. Although phylogenetic analysis of the RdRp domain demonstrated that SsBRV1 is related to Botrytis porri RNA virus 1 (BpRV1) and Ustilago maydis dsRNA virus-H1, the structure proteins of SsBRV1 do not have any significant sequence similarities with other known viral proteins with the exception of those of BpRV1. SsBRV1 carrying dsRNA3 seems to have no obvious effects on the colony morphology, but can significantly reduce the growth rate and virulence of S. sclerotiorum. These findings provide new insights into the virus taxonomy, virus evolution and the interactions between SsBRV1 and the fungal hosts.
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Affiliation(s)
- Lijiang Liu
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Qihua Wang
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Jiasen Cheng
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Yanping Fu
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Daohong Jiang
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
| | - Jiatao Xie
- State Key Laboratory of Agricultural Microbiology and The Provincial Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University Wuhan, China
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9
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Wang IN, Hu CC, Lee CW, Yen SM, Yeh WB, Hsu YH, Lin NS. Genetic diversity and evolution of satellite RNAs associated with the bamboo mosaic virus. PLoS One 2014; 9:e108015. [PMID: 25275532 PMCID: PMC4183488 DOI: 10.1371/journal.pone.0108015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2014] [Accepted: 08/20/2014] [Indexed: 02/08/2023] Open
Abstract
Satellite RNAs (satRNAs) are subviral agents that depend on cognate helper viruses for genome replication and encapsidation. Their negative impacts on helper viruses have been exploited to control plant viral diseases. SatBaMV is a commonly found satRNA associated with Bamboo mosaic virus (BaMV) that infects diverse bamboo species in the field. To investigate the genetic diversity and evolution of satRNAs, we examined seven satBaMV populations derived from five bamboo species and cultivars from Taiwan, China, and India and one from the greenhouse. We found 3 distinct clades among the seven populations. Clade I is consisted of all satBaMV isolates, except for those from Dendrocalamus latiflorus in Taiwan and Bambusa vulgaris in India, which belong to Clades II and III, respectively. Interestingly, nucleotide diversity was lower for Clade I than II and III. However, the nucleotide diversity did not seem to depend on bamboo species or geographic location. Our population genetic analyses revealed the presence of excessive low-frequency polymorphic sites, which suggests that the satBaMV population was under purifying selection and/or population expansion. Further analysis of P20, the only satBaMV gene that encodes a non-structural protein involved in the long-distance movement of satBaMV, showed evidence of purifying selection. Taken together, our results suggest that purifying selection against defective P20 protein is responsible at least in part for the evolution of the satBaMV genome.
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Affiliation(s)
- Ing-Nang Wang
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China
- Department of Biological Sciences, University at Albany, Albany, New York, United States of America
| | - Chung-Chi Hu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan, Republic of China
| | - Ching-Wei Lee
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan, Republic of China
| | - Sih-Min Yen
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan, Republic of China
| | - Wen-Bing Yeh
- Department of Entomology, National Chung Hsin University, Taichung, Taiwan, Republic of China
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan, Republic of China
| | - Na-Sheng Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, Republic of China
- * E-mail:
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10
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Park MR, Seo JK, Kim KH. Viral and nonviral elements in potexvirus replication and movement and in antiviral responses. Adv Virus Res 2013; 87:75-112. [PMID: 23809921 DOI: 10.1016/b978-0-12-407698-3.00003-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In Potato virus X, a member of the genus Potexvirus, special sequences and structures at the 5' and 3' ends of the nontranslated region function as cis-acting elements for viral replication. These elements greatly affect interactions between viral RNAs and those between viral RNAs and host factors. The potexvirus genome encodes five open-reading frames. Viral replicase, which is required for the synthesis of viral RNA, binds viral RNA elements and host factors to form a viral replication complex at the host cellular membrane. The coat protein (CP) and three viral movement proteins (TGB1, TGB2, and TGB3) have critical roles in mediating cell-to-cell viral movement through plasmodesmata by virion formation or by nonvirion ribonucleoprotein (RNP) complex formation with viral movement proteins (TGBs). The RNP complex, like TGB1-CP-viral RNA, is associated with viral replicase and used for immediate reinitiation of viral replication in newly invaded cells. Higher plants have defense mechanisms against potexviruses such as Rx-mediated resistance and RNA silencing. The CP acts as an avirulence effector for plant defense mechanisms, while TGB1 functions as a viral suppressor of RNA silencing, which is the mechanism of innate immune resistance. Here, we describe recent findings concerning the involvement of viral and host factors in potexvirus replication and in antiviral responses to potexvirus infection.
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Affiliation(s)
- Mi-Ri Park
- Department of Agricultural Biotechnology, Plant Genomics and Breeding Institute, Seoul National University, Seoul, Republic of Korea
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11
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Chen IH, Cheng JH, Huang YW, Lin NS, Hsu YH, Tsai CH. Characterization of the polyadenylation activity in a replicase complex from Bamboo mosaic virus-infected Nicotiana benthamiana plants. Virology 2013; 444:64-70. [PMID: 23768785 PMCID: PMC7111917 DOI: 10.1016/j.virol.2013.05.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Revised: 05/20/2013] [Accepted: 05/22/2013] [Indexed: 12/30/2022]
Abstract
Bamboo mosaic virus (BaMV) has a positive-sense single-stranded RNA genome with a 5' cap and a 3' poly(A) tail. To characterize polyadenylation activity in the BaMV replicase complex, we performed the in vitro polyadenylation with various BaMV templates. We conducted a polyadenylation activity assay for BaMV RNA by using a partially purified BaMV replicase complex. The results showed that approximately 200 adenylates at the 3' end of the RNA were generated on the endogenous RNA templates. Specific fractions derived from uninfected Nicotiana benthamiana plants enhanced the polyadenylation activity, implying that host factors are involved in polyadenylation. Furthermore, polyadenylation can be detected in newly synthesized plus-strand RNA in vitro when using the exogenous BaMV minus-strand minigenome. For polyadenylation on the exogenous plus-strand minigenome, the 3' end requires at least 4A to reach 22% polyadenylation activity. The results indicate that the BaMV replicase complex recognizes the 3' end of BaMV for polyadenylation.
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Affiliation(s)
- I-Hsuan Chen
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Jai-Hong Cheng
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Ying-Wen Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Na-Sheng Lin
- The Institute of Plant and Microbial Biology, Academia Sinica, Taipei 115, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
- Graduate Institute of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
| | - Ching-Hsiu Tsai
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
- Graduate Institute of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
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12
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Huang YW, Hu CC, Liou MR, Chang BY, Tsai CH, Meng M, Lin NS, Hsu YH. Hsp90 interacts specifically with viral RNA and differentially regulates replication initiation of Bamboo mosaic virus and associated satellite RNA. PLoS Pathog 2012; 8:e1002726. [PMID: 22654666 PMCID: PMC3359997 DOI: 10.1371/journal.ppat.1002726] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2011] [Accepted: 04/16/2012] [Indexed: 12/22/2022] Open
Abstract
Host factors play crucial roles in the replication of plus-strand RNA viruses. In this report, a heat shock protein 90 homologue of Nicotiana benthamiana, NbHsp90, was identified in association with partially purified replicase complexes from BaMV-infected tissue, and shown to specifically interact with the 3' untranslated region (3' UTR) of BaMV genomic RNA, but not with the 3' UTR of BaMV-associated satellite RNA (satBaMV RNA) or that of genomic RNA of other viruses, such as Potato virus X (PVX) or Cucumber mosaic virus (CMV). Mutational analyses revealed that the interaction occurs between the middle domain of NbHsp90 and domain E of the BaMV 3' UTR. The knockdown or inhibition of NbHsp90 suppressed BaMV infectivity, but not that of satBaMV RNA, PVX, or CMV in N. benthamiana. Time-course analysis further revealed that the inhibitory effect of 17-AAG is significant only during the immediate early stages of BaMV replication. Moreover, yeast two-hybrid and GST pull-down assays demonstrated the existence of an interaction between NbHsp90 and the BaMV RNA-dependent RNA polymerase. These results reveal a novel role for NbHsp90 in the selective enhancement of BaMV replication, most likely through direct interaction with the 3' UTR of BaMV RNA during the initiation of BaMV RNA replication.
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Affiliation(s)
- Ying Wen Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Chung Chi Hu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Ming Ru Liou
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Ban Yang Chang
- Institute of Biochemistry, National Chung Hsing University, Taichung, Taiwan
| | - Ching Hsiu Tsai
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Menghsiao Meng
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Na Sheng Lin
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yau Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
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Chen HC, Kong LR, Yeh TY, Cheng CP, Hsu YH, Lin NS. The conserved 5' apical hairpin stem loops of bamboo mosaic virus and its satellite RNA contribute to replication competence. Nucleic Acids Res 2012; 40:4641-52. [PMID: 22278884 PMCID: PMC3378871 DOI: 10.1093/nar/gks030] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2011] [Revised: 12/30/2011] [Accepted: 01/05/2012] [Indexed: 11/29/2022] Open
Abstract
Satellite RNAs associated with Bamboo mosaic virus (satBaMVs) depend on BaMV for replication and encapsidation. Certain satBaMVs isolated from natural fields significantly interfere with BaMV replication. The 5' apical hairpin stem loop (AHSL) of satBaMV is the major determinant in interference with BaMV replication. In this study, by in vivo competition assay, we revealed that the sequence and structure of AHSL, along with specific nucleotides (C(60) and C(83)) required for interference with BaMV replication, are also involved in replication competition among satBaMV variants. Moreover, all of the 5' ends of natural BaMV isolates contain the similar AHSLs having conserved nucleotides (C(64) and C(86)) with those of interfering satBaMVs, suggesting their co-evolution. Mutational analyses revealed that C(86) was essential for BaMV replication, and that replacement of C(64) with U reduced replication efficiency. The non-interfering satBaMV interfered with BaMV replication with the BaMV-C64U mutant as helper. These findings suggest that two cytosines at the equivalent positions in the AHSLs of BaMV and satBaMV play a crucial role in replication competence. The downregulation level, which is dependent upon the molar ratio of interfering satBaMV to BaMV, implies that there is competition for limited replication machinery.
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Affiliation(s)
- Hsin-Chuan Chen
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei and Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Lih-Ren Kong
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei and Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Ting-Yu Yeh
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei and Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Chi-Ping Cheng
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei and Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Yau-Heiu Hsu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei and Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Na-Sheng Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei and Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
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Prasanth KR, Huang YW, Liou MR, Wang RYL, Hu CC, Tsai CH, Meng M, Lin NS, Hsu YH. Glyceraldehyde 3-phosphate dehydrogenase negatively regulates the replication of Bamboo mosaic virus and its associated satellite RNA. J Virol 2011; 85:8829-40. [PMID: 21715476 PMCID: PMC3165797 DOI: 10.1128/jvi.00556-11] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2011] [Accepted: 06/21/2011] [Indexed: 01/24/2023] Open
Abstract
The identification of cellular proteins associated with virus replicase complexes is crucial to our understanding of virus-host interactions, influencing the host range, replication, and virulence of viruses. A previous in vitro study has demonstrated that partially purified Bamboo mosaic virus (BaMV) replicase complexes can be employed for the replication of both BaMV genomic and satellite BaMV (satBaMV) RNAs. In this study, we investigated the BaMV and satBaMV 3' untranslated region (UTR) binding proteins associated with these replicase complexes. Two cellular proteins with molecular masses of ∼35 and ∼55 kDa were specifically cross-linked with RNA elements, whereupon the ∼35-kDa protein was identified as the glycolytic enzyme glyceraldehyde 3-phosphate dehydrogenase (GAPDH). Gel mobility shift assays confirmed the direct interaction of GAPDH with the 3' UTR sequences, and competition gel shift analysis revealed that GAPDH binds preferentially to the positive-strand BaMV and satBaMV RNAs over the negative-strand RNAs. It was observed that the GAPDH protein binds to the pseudoknot poly(A) tail of BaMV and stem-loop-C poly(A) tail of satBaMV 3' UTR RNAs. It is important to note that knockdown of GAPDH in Nicotiana benthamiana enhances the accumulation of BaMV and satBaMV RNA; conversely, transient overexpression of GAPDH reduces the accumulation of BaMV and satBaMV RNA. The recombinant GAPDH principally inhibits the synthesis of negative-strand RNA in exogenous RdRp assays. These observations support the contention that cytosolic GAPDH participates in the negative regulation of BaMV and satBaMV RNA replication.
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Affiliation(s)
- K. Reddisiva Prasanth
- Graduate Institute of Biotechnology, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan, Republic of China
| | - Ying-Wen Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan, Republic of China
| | - Ming-Ru Liou
- Graduate Institute of Biotechnology, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan, Republic of China
| | - Robert Yung-Liang Wang
- Department of Biomedical Sciences and Research Center for Emerging Viral Infections, Chang Gung University, Tao Yuan 33302, Taiwan, Republic of China
| | - Chung-Chi Hu
- Graduate Institute of Biotechnology, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan, Republic of China
| | - Ching-Hsiu Tsai
- Graduate Institute of Biotechnology, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan, Republic of China
| | - Menghsiao Meng
- Graduate Institute of Biotechnology, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan, Republic of China
| | - Na-Sheng Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Nankang, Taipei 11529, Taiwan, Republic of China
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, 250 Kuo-Kuang Road, Taichung 40227, Taiwan, Republic of China
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15
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Lin KY, Cheng CP, Chang BCH, Wang WC, Huang YW, Lee YS, Huang HD, Hsu YH, Lin NS. Global analyses of small interfering RNAs derived from Bamboo mosaic virus and its associated satellite RNAs in different plants. PLoS One 2010; 5:e11928. [PMID: 20689857 PMCID: PMC2914070 DOI: 10.1371/journal.pone.0011928] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Accepted: 07/08/2010] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Satellite RNAs (satRNAs), virus parasites, are exclusively associated with plant virus infection and have attracted much interest over the last 3 decades. Upon virus infection, virus-specific small interfering RNAs (vsiRNAs) are produced by dicer-like (DCL) endoribonucleases for anti-viral defense. The composition of vsiRNAs has been studied extensively; however, studies of satRNA-derived siRNAs (satsiRNAs) or siRNA profiles after satRNA co-infection are limited. Here, we report on the small RNA profiles associated with infection with Bamboo mosaic virus (BaMV) and its two satellite RNAs (satBaMVs) in Nicotiana benthamiana and Arabidopsis thaliana. METHODOLOGY/PRINCIPAL FINDINGS Leaves of N. benthamiana or A. thaliana inoculated with water, BaMV alone or co-inoculated with interfering or noninterfering satBaMV were collected for RNA extraction, then large-scale Solexa sequencing. Up to about 20% of total siRNAs as BaMV-specific siRNAs were accumulated in highly susceptible N. benthamiana leaves inoculated with BaMV alone or co-inoculated with noninterfering satBaMV; however, only about 0.1% of vsiRNAs were produced in plants co-infected with interfering satBaMV. The abundant region of siRNA distribution along BaMV and satBaMV genomes differed by host but not by co-infection with satBaMV. Most of the BaMV and satBaMV siRNAs were 21 or 22 nt, of both (+) and (-) polarities; however, a higher proportion of 22-nt BaMV and satBaMV siRNAs were generated in N. benthamiana than in A. thaliana. Furthermore, the proportion of non-viral 24-nt siRNAs was greatly increased in N. benthamiana after virus infection. CONCLUSIONS/SIGNIFICANCE The overall composition of vsiRNAs and satsiRNAs in the infected plants reflect the combined action of virus, satRNA and different DCLs in host plants. Our findings suggest that the structure and/or sequence demands of various DCLs in different hosts may result in differential susceptibility to the same virus. DCL2 producing 24-nt siRNAs under biotic stresses may play a vital role in the antiviral mechanism in N. benthamiana.
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Affiliation(s)
- Kuan-Yu Lin
- Institute of Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Chi-Ping Cheng
- Department of Life Science, Tzu Chi University, Hualien, Taiwan
| | | | - Wei-Chi Wang
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsin-Chu, Taiwan
| | - Ying-Wen Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Yun-Shien Lee
- Department of Biotechnology, Ming Chuan University, Taoyuan, Taiwan
| | - Hsien-Da Huang
- Institute of Bioinformatics and Systems Biology, National Chiao Tung University, Hsin-Chu, Taiwan
- Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Na-Sheng Lin
- Institute of Biotechnology, National Cheng Kung University, Tainan, Taiwan
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
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Satellite RNAs and Satellite Viruses of Plants. Viruses 2009; 1:1325-50. [PMID: 21994595 PMCID: PMC3185516 DOI: 10.3390/v1031325] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2009] [Revised: 12/07/2009] [Accepted: 12/07/2009] [Indexed: 12/24/2022] Open
Abstract
The view that satellite RNAs (satRNAs) and satellite viruses are purely molecular parasites of their cognate helper viruses has changed. The molecular mechanisms underlying the synergistic and/or antagonistic interactions among satRNAs/satellite viruses, helper viruses, and host plants are beginning to be comprehended. This review aims to summarize the recent achievements in basic and practical research, with special emphasis on the involvement of RNA silencing mechanisms in the pathogenicity, population dynamics, and, possibly, the origin(s) of these subviral agents. With further research following current trends, the comprehensive understanding of satRNAs and satellite viruses could lead to new insights into the trilateral interactions among host plants, viruses, and satellites.
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