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Lee SC, Pai H, Huang YW, He MH, Song YL, Kuo SY, Chang WC, Hsu YH, Lin NS. Exploring the Multifunctional Roles of Odontoglossum Ringspot Virus P126 in Facilitating Cymbidium Mosaic Virus Cell-to-Cell Movement during Mixed Infection. Viruses 2021; 13:1552. [PMID: 34452417 PMCID: PMC8402721 DOI: 10.3390/v13081552] [Citation(s) in RCA: 1] [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: 06/28/2021] [Revised: 07/31/2021] [Accepted: 08/02/2021] [Indexed: 12/11/2022] Open
Abstract
Synergistic interactions among viruses, hosts and/or transmission vectors during mixed infection can alter viral titers, symptom severity or host range. Viral suppressors of RNA silencing (VSRs) are considered one of such factors contributing to synergistic responses. Odontoglossum ringspot virus (ORSV) and cymbidium mosaic virus (CymMV), which are two of the most significant orchid viruses, exhibit synergistic symptom intensification in Phalaenopsis orchids with unilaterally enhanced CymMV movement by ORSV. In order to reveal the underlying mechanisms, we generated infectious cDNA clones of ORSV and CymMV isolated from Phalaenopsis that exerted similar unilateral synergism in both Phalaenopsis orchid and Nicotiana benthamiana. Moreover, we show that the ORSV replicase P126 is a VSR. Mutagenesis analysis revealed that mutation of the methionine in the carboxyl terminus of ORSV P126 abolished ORSV replication even though some P126 mutants preserved VSR activity, indicating that the VSR function of P126 alone is not sufficient for viral replication. Thus, P126 functions in both ORSV replication and as a VSR. Furthermore, P126 expression enhanced cell-to-cell movement and viral titers of CymMV in infected Phalaenopsis flowers and N. benthamiana leaves. Taking together, both the VSR and protein function of P126 might be prerequisites for unilaterally enhancing CymMV cell-to-cell movement by ORSV.
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Affiliation(s)
- Shu-Chuan Lee
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-C.L.); (H.P.); (M.-H.H.); (Y.-L.S.)
| | - Hsuan Pai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-C.L.); (H.P.); (M.-H.H.); (Y.-L.S.)
| | - Ying-Wen Huang
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan; (Y.-W.H.); (S.-Y.K.); (Y.-H.H.)
| | - Meng-Hsun He
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-C.L.); (H.P.); (M.-H.H.); (Y.-L.S.)
| | - Yun-Lin Song
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-C.L.); (H.P.); (M.-H.H.); (Y.-L.S.)
| | - Song-Yi Kuo
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan; (Y.-W.H.); (S.-Y.K.); (Y.-H.H.)
| | - Wen-Chi Chang
- College of Biosciences and Biotechnology, Institute of Tropical Plant Sciences, National Cheng Kung University, Tainan 70101, Taiwan;
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan; (Y.-W.H.); (S.-Y.K.); (Y.-H.H.)
| | - Na-Sheng Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan; (S.-C.L.); (H.P.); (M.-H.H.); (Y.-L.S.)
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Pai H, Jean W, Lee Y, Chang YA, Lin N. Genome-wide analysis of small RNAs from Odontoglossum ringspot virus and Cymbidium mosaic virus synergistically infecting Phalaenopsis. MOLECULAR PLANT PATHOLOGY 2020; 21:188-205. [PMID: 31724809 PMCID: PMC6988431 DOI: 10.1111/mpp.12888] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Cymbidium mosaic virus (CymMV) and Odontoglossum ringspot virus (ORSV) are the two most prevalent viruses infecting orchids and causing economic losses worldwide. Mixed infection of CymMV and ORSV could induce intensified symptoms as early at 10 days post-inoculation in inoculated Phalaenopsis amabilis, where CymMV pathogenesis was unilaterally enhanced by ORSV. To reveal the antiviral RNA silencing activity in orchids, we characterized the viral small-interfering RNAs (vsiRNAs) from CymMV and ORSV singly or synergistically infecting P. amabilis. We also temporally classified the inoculated leaf-tip tissues and noninoculated adjacent tissues as late and early stages of infection, respectively. Regardless of early or late stage with single or double infection, CymMV and ORSV vsiRNAs were predominant in 21- and 22-nt sizes, with excess positive polarity and under-represented 5'-guanine. While CymMV vsiRNAs mainly derived from RNA-dependent RNA polymerase-coding regions, ORSV vsiRNAs encompassed the coat protein gene and 3'-untranslated region, with a specific hotspot residing in the 3'-terminal pseudoknot. With double infection, CymMV vsiRNAs increased more than 5-fold in number with increasing virus titres. Most vsiRNA features remained unchanged with double inoculation, but additional ORSV vsiRNA hotspot peaks were prominent. The potential vsiRNA-mediated regulation of the novel targets in double-infected tissues thereby provides a different view of CymMV and ORSV synergism. Hence, temporally profiled vsiRNAs from taxonomically distinct CymMV and ORSV illustrate active antiviral RNA silencing in their natural host, Phalaenopsis, during both early and late stages of infection. Our findings provide insights into offence-defence interactions among CymMV, ORSV and orchids.
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Affiliation(s)
- Hsuan Pai
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan11529
| | - Wen‐Han Jean
- Agricultural Biotechnology Research CenterAcademia SinicaTaipeiTaiwan11529
| | - Yun‐Shien Lee
- Department of BiotechnologyMing Chuan UniversityTao‐YuanTaiwan33348
| | - Yao‐Chien Alex Chang
- Department of Horticulture and Landscape ArchitectureNational Taiwan UniversityTaipeiTaiwan10617
| | - Na‐Sheng Lin
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan11529
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Ur Rehman A, Li Z, Yang Z, Waqas M, Wang G, Xu W, Li F, Hong N. The Coat Protein of Citrus Yellow Vein Clearing Virus Interacts with Viral Movement Proteins and Serves as an RNA Silencing Suppressor. Viruses 2019; 11:E329. [PMID: 30959816 PMCID: PMC6520955 DOI: 10.3390/v11040329] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Revised: 03/27/2019] [Accepted: 04/04/2019] [Indexed: 01/29/2023] Open
Abstract
Citrus yellow vein clearing virus is a newly accepted member of the genus Mandarivirus in the family Alphaflexiviridae. The triple gene block proteins (TGBp1, TGBp2 and TGBp3) encoded by plant viruses in this family function on facilitating virus movement. However, the protein function of citrus yellow vein clearing virus (CYVCV) have never been explored. Here, we showed in both yeast two-hybrid (Y2H) and bimolecular fluorescence (BiFC) assays that the coat protein (CP), TGBp1 and TGBp2 of CYVCV are self-interacting. Its CP also interacts with all three TGB proteins, and TGBp1 and TGBp2 interact with each other but not with TGBp3. Furthermore, the viral CP colocalizes with TGBp1 and TGBp3 at the plasmodesmata (PD) of epidermal cells of Nicotiana benthamiana leaves, and TGBp1 can translocate TGBp2 from granular-like structures embedded within ER networks to the PD. The results suggest that these proteins could coexist at the PD of epidermal cells of N. benthamiana. Using Agrobacterium infiltration-mediated RNA silencing assays, we show that CYVCV CP is a strong RNA silencing suppressor (RSS) triggered by positive-sense green fluorescent protein (GFP) RNA. The presented results provide insights for further revealing the mechanism of the viral movement and suppression of RNA silencing.
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Affiliation(s)
- Atta Ur Rehman
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Horticultural Crop (Fruit Trees) Biology and Germplasm Creation of the Ministry of Agriculture, Wuhan 430070, China.
- Plant Pathology Section, Central Cotton Research Institute, Sakrand, Sindh 67210, Pakistan.
| | - Zhuoran Li
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
| | - Zuokun Yang
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Horticultural Crop (Fruit Trees) Biology and Germplasm Creation of the Ministry of Agriculture, Wuhan 430070, China.
| | - Muhammad Waqas
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
| | - Guoping Wang
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Horticultural Crop (Fruit Trees) Biology and Germplasm Creation of the Ministry of Agriculture, Wuhan 430070, China.
| | - Wenxing Xu
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Horticultural Crop (Fruit Trees) Biology and Germplasm Creation of the Ministry of Agriculture, Wuhan 430070, China.
| | - Feng Li
- Key Laboratory of Horticultural Plant Biology (MOE), College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan 430070, China.
| | - Ni Hong
- Key Lab of Plant Pathology of Hubei Province, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan 430070, China.
- Key Laboratory of Horticultural Crop (Fruit Trees) Biology and Germplasm Creation of the Ministry of Agriculture, Wuhan 430070, China.
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Makarov VV, Kalinina NO. Structure and Noncanonical Activities of Coat Proteins of Helical Plant Viruses. BIOCHEMISTRY (MOSCOW) 2016; 81:1-18. [PMID: 26885578 DOI: 10.1134/s0006297916010016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The main function of virus coat protein is formation of the capsid that protects the virus genome against degradation. However, besides the structural function, coat proteins have many additional important activities in the infection cycle of the virus and in the defense response of host plants to viral infection. This review focuses on noncanonical functions of coat proteins of helical RNA-containing plant viruses with positive genome polarity. Analysis of data on the structural organization of coat proteins of helical viruses has demonstrated that the presence of intrinsically disordered regions within the protein structure plays an important role in implementation of nonstructural functions and largely determines the multifunctionality of coat proteins.
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Affiliation(s)
- V V Makarov
- Lomonosov Moscow State University, Belozersky Institute of Physico-Chemical Biology, Moscow, 119991, Russia.
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Liou MR, Hu CC, Chou YL, Chang BY, Lin NS, Hsu YH. Viral elements and host cellular proteins in intercellular movement of Bamboo mosaic virus. Curr Opin Virol 2015; 12:99-108. [PMID: 25951346 DOI: 10.1016/j.coviro.2015.04.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Revised: 04/15/2015] [Accepted: 04/17/2015] [Indexed: 12/23/2022]
Abstract
As a member of the genus Potexvirus, Bamboo mosaic virus (BaMV) also belongs to the plant viruses that encode triple gene block proteins (TGBps) for intercellular movement within the host plants. Recent studies of the movement mechanisms of BaMV have revealed similarities and differences between BaMV and other potexviruses. This review focuses on the general aspects of viral and host elements involved in BaMV movement, the interactions among these elements, and the possible pathways for intra- and intercellular trafficking of BaMV. Major features of BaMV trafficking that have not been demonstrated in other potexviruses include: (i) the involvement of replicase, (ii) fine regulation by coat protein phosphorylation, (iii) the key roles played by TGBp3, (iv) the use of virions as the major transported form, and (v) the involvement of specific host factors, such as Ser/Thr kinase-like protein of Nicotiana benthamiana. We also highlight areas for future study that will provide a more comprehensive understanding of the detailed interactions among viral movement proteins and host factors, as well as the regulatory mechanisms of virus movement. Finally, a model based on the current knowledge is proposed to depict the diverse abilities of BaMV to utilize a wide range of mechanisms for efficient intercellular movement.
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Affiliation(s)
- Ming-Ru Liou
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Chung-Chi Hu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Yuan-Lin Chou
- Institute of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan
| | - Ban-Yang Chang
- Institute of Biochemistry, National Chung Hsing University, Taichung 40227, Taiwan
| | - Na-Sheng Lin
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan; Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yau-Heiu Hsu
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung 40227, Taiwan.
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Multiple functions of capsid proteins in (+) stranded RNA viruses during plant–virus interactions. Virus Res 2015; 196:140-9. [DOI: 10.1016/j.virusres.2014.11.014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Revised: 11/10/2014] [Accepted: 11/12/2014] [Indexed: 11/18/2022]
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Mathioudakis MM, Rodríguez-Moreno L, Sempere RN, Aranda MA, Livieratos I. Multifaceted capsid proteins: multiple interactions suggest multiple roles for Pepino mosaic virus capsid protein. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:1356-69. [PMID: 25162316 DOI: 10.1094/mpmi-07-14-0195-r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Pepino mosaic virus (PepMV) (family Alphaflexiviridae, genus Potexvirus) is a mechanically transmitted tomato pathogen that, over the last decade, has evolved from emerging to endemic worldwide. Here, two heat-shock cognate (Hsc70) isoforms were identified as part of the coat protein (CP)/Hsc70 complex in vivo, following full-length PepMV and CP agroinoculation. PepMV accumulation was severely reduced in Hsp70 virus-induced gene silenced and in quercetin-treated Nicotiana benthamiana plants. Similarly, in vitro-transcribed as well as virion RNA input levels were reduced in quercetin-treated protoplasts, suggesting an essential role for Hsp70 in PepMV replication. As for Potato virus X, the PepMV CP and triple gene-block protein 1 (TGBp1) self-associate and interact with each other in vitro but, unlike in the prototype, both PepMV proteins represent suppressors of transgene-induced RNA silencing with different modes of action; CP is a more efficient suppressor of RNA silencing, sequesters the silencing signal by preventing its spread to neighboring cells and its systemic movement. Here, we provide evidence for additional roles of the PepMV CP and host-encoded Hsp70 in viral infection, the first as a truly multifunctional protein able to specifically bind to a host chaperone and to counterattack an RNA-based defense mechanism, and the latter as an essential factor for PepMV infection.
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Minato N, Komatsu K, Okano Y, Maejima K, Ozeki J, Senshu H, Takahashi S, Yamaji Y, Namba S. Efficient foreign gene expression in planta using a plantago asiatica mosaic virus-based vector achieved by the strong RNA-silencing suppressor activity of TGBp1. Arch Virol 2014; 159:885-96. [PMID: 24154949 DOI: 10.1007/s00705-013-1860-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 09/24/2013] [Indexed: 01/04/2023]
Abstract
Plant virus expression vectors provide a powerful tool for basic research as well as for practical applications. Here, we report the construction of an expression vector based on plantago asiatica mosaic virus (PlAMV), a member of the genus Potexvirus. Modification of a vector to enhance the expression of a foreign gene, combined with the use of the foot-and-mouth disease virus 2A peptide, allowed efficient expression of the foreign gene in two model plant species, Arabidopsis thaliana and Nicotiana benthamiana. Comparison with the widely used potato virus X (PVX) vector demonstrated that the PlAMV vector retains an inserted foreign gene for a longer period than PVX. Moreover, our results showed that the GFP expression construct PlAMV-GFP exhibits stronger RNA silencing suppression activity than PVX-GFP, which is likely to contribute to the stability of the PlAMV vector.
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Affiliation(s)
- Nami Minato
- Laboratory of Plant Pathology, Department of Agricultural and Environmental Biology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
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Hung CJ, Hu CC, Lin NS, Lee YC, Meng M, Tsai CH, Hsu YH. Two key arginine residues in the coat protein of Bamboo mosaic virus differentially affect the accumulation of viral genomic and subgenomic RNAs. MOLECULAR PLANT PATHOLOGY 2014; 15:196-210. [PMID: 24393453 PMCID: PMC6638855 DOI: 10.1111/mpp.12080] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The interactions between viral RNAs and coat proteins (CPs) are critical for the efficient completion of infection cycles of RNA viruses. However, the specificity of the interactions between CPs and genomic or subgenomic RNAs remains poorly understood. In this study, Bamboo mosaic virus (BaMV) was used to analyse such interactions. Using reversible formaldehyde cross-linking and mass spectrometry, two regions in CP, each containing a basic amino acid (R99 and R227, respectively), were identified to bind directly to the 5' untranslated region of BaMV genomic RNA. Analyses of the alanine mutations of R99 and R227 revealed that the secondary structures of CP were not affected significantly, whereas the accumulation of BaMV genomic, but not subgenomic, RNA was severely decreased at 24 h post-inoculation in the inoculated protoplasts. In the absence of CP, the accumulation levels of genomic and subgenomic RNAs were decreased to 1.1%-1.5% and 33%-40% of that of the wild-type (wt), respectively, in inoculated leaves at 5 days post-inoculation (dpi). In contrast, in the presence of mutant CPs, the genomic RNAs remained about 1% of that of wt, whereas the subgenomic RNAs accumulated to at least 87%, suggesting that CP might increase the accumulation of subgenomic RNAs. The mutations also restricted viral movement and virion formation in Nicotiana benthamiana leaves at 5 dpi. These results demonstrate that R99 and R227 of CP play crucial roles in the accumulation, movement and virion formation of BaMV RNAs, and indicate that genomic and subgenomic RNAs interact differently with BaMV CP.
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Affiliation(s)
- Chien-Jen Hung
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, 40227, Taiwan
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