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Lv J, Mo Y, Deng M, Xu J, Xu B, Li X, Li J, Jiang C, Zhou Y, Wang Z, Yang Z, Zhao K. Pathological Features and Genetic Polymorphism Analysis of Tomato Spotted Wilt Virus in Infected Tomato Fruit. Genes (Basel) 2023; 14:1788. [PMID: 37761928 PMCID: PMC10531454 DOI: 10.3390/genes14091788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Revised: 09/07/2023] [Accepted: 09/11/2023] [Indexed: 09/29/2023] Open
Abstract
An in-house tomato inbred line, YNAU335, was planted in a greenhouse in spring from 2014 to 2017, and showed immunity to tomato spotted wilt virus (TSWV). YNAU335 was infected with TSWV in the spring from 2018 to 2020, and disease was observed on the leaves, sepals, and fruits. In 2021 and 2022, YNAU335 was planted in spring in the same greenhouse, which was suspected of being infected with TSWV, and visible disease symptoms were observed on the fruits. Transmission electron microscopy, deep sequencing of small RNAs, and molecular mutation diagnosis were used to analyze the pathological features and genetic polymorphism of TSWV infecting tomato fruit. Typical TSWV virions were observed in the infected fruits, but not leaves from YNAU335 grown between 2021 and 2022, and cross-infection was very rarely observed. The number of mitochondria and chloroplasts increased, but the damage to the mitochondria was greater than that seen in the chloroplasts. Small RNA deep sequencing revealed the presence of multiple viral species in TSWV-infected and non-infected tomato samples grown between 2014-2022. Many virus species, including TSWV, which accounted for the largest proportion, were detected in the TSWV-infected tomato leaves and fruit. However, a variety of viruses other than TSWV were also detected in the non-infected tissues. The amino acids of TSWV nucleocapsid proteins (NPs) and movement proteins (MPs) from diseased fruits of YNAU335 picked in 2021-2022 were found to be very diverse. Compared with previously identified NPs and MPs from TSWV isolates, those found in this study could be divided into three types: non-resistance-breaking, resistance-breaking, and other isolates. The number of positive clones and a comparison with previously identified amino acid mutations suggested that mutation F at AA118 of the MP (GenBank OL310707) is likely the key to breaking the resistance to TSWV, and this mutation developed only in the infected fruit of YNAU335 grown in 2021 and 2022.
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Affiliation(s)
- Junheng Lv
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Yunrong Mo
- College of Food Science and Technology, Yunnan Agricultural University, Kunming 650201, China
| | - Minghua Deng
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Junqiang Xu
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Bin Xu
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Xinyun Li
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Jing Li
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Caiqian Jiang
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Ying Zhou
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Ziran Wang
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Zhengan Yang
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
| | - Kai Zhao
- College of Landscape and Horticulture, Yunnan Agricultural University, Kunming 650201, China
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Kormelink R, Verchot J, Tao X, Desbiez C. The Bunyavirales: The Plant-Infecting Counterparts. Viruses 2021; 13:v13050842. [PMID: 34066457 PMCID: PMC8148189 DOI: 10.3390/v13050842] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 04/26/2021] [Accepted: 04/29/2021] [Indexed: 12/18/2022] Open
Abstract
Negative-strand (-) RNA viruses (NSVs) comprise a large and diverse group of viruses that are generally divided in those with non-segmented and those with segmented genomes. Whereas most NSVs infect animals and humans, the smaller group of the plant-infecting counterparts is expanding, with many causing devastating diseases worldwide, affecting a large number of major bulk and high-value food crops. In 2018, the taxonomy of segmented NSVs faced a major reorganization with the establishment of the order Bunyavirales. This article overviews the major plant viruses that are part of the order, i.e., orthospoviruses (Tospoviridae), tenuiviruses (Phenuiviridae), and emaraviruses (Fimoviridae), and provides updates on the more recent ongoing research. Features shared with the animal-infecting counterparts are mentioned, however, special attention is given to their adaptation to plant hosts and vector transmission, including intra/intercellular trafficking and viral counter defense to antiviral RNAi.
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Affiliation(s)
- Richard Kormelink
- Laboratory of Virology, Department of Plant Sciences, Wageningen University, Droevendaalsesteeg 1, 6708 PB Wageningen, The Netherlands
| | - Jeanmarie Verchot
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX 77843, USA
| | - Xiaorong Tao
- Department of Plant Pathology, Nanjing Agricultural University, Nanjing 210095, China
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Revisiting Orthotospovirus phylogeny using full-genome data and testing the contribution of selection, recombination and segment reassortment in the origin of members of new species. Arch Virol 2021; 166:491-499. [PMID: 33394171 DOI: 10.1007/s00705-020-04902-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/14/2020] [Indexed: 01/08/2023]
Abstract
The family Tospoviridae of the order Bunyavirales is constituted of tri-segmented negative-sense single-stranded RNA viruses that infect plants and are also able to replicate in their insect vectors in a persistent manner. The family is composed of a single genus, Orthotospovirus, whose type species is Tomato spotted wilt orthotospovirus. Previous studies assessing the phylogenetic relationships within this genus were based on partial genomic sequences, resulting in unresolved clades and a poor assessment of the roles of recombination and segment reassortment during mixed infections. Full genome sequences of members of recognized Orthotospovirus species are now available at NCBI. In this study, we examined 67 complete genome sequences from members of 22 species. Our study confirms the existence of four phylogroups (A to D), grouped in two major clades (A-B and C-D) within the genus. We found strong evidence that within-segment recombination events and reassortment of segments during mixed infections have been involved in the origin of new orthotospoviruses. Also, selection pressures were analyzed for each gene, and evidence of positive selection was found in all genes.
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Zhou Y, Ghidey MR, Pruett G, Kearney CM. The use of functionally deficient viral vectors as visualization tools to reveal complementation patterns between plant viruses and the silencing suppressor p19. J Virol Methods 2020; 286:113980. [PMID: 33010375 DOI: 10.1016/j.jviromet.2020.113980] [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: 11/02/2019] [Revised: 08/10/2020] [Accepted: 09/24/2020] [Indexed: 10/23/2022]
Abstract
Plant virus transport complementation is classically observed as a helper virus allowing another virus to regain cell-to-cell or systemic movement through a restrictive host plant (Malyshenko et al., 1989). The complementation effect is usually studied by observing virus infection after co-infection or super-inoculation of the helper virus. We herein demonstrate the utility of functionally deficient viral vectors as tools to determine the contribution of individual viral genes to plant viral transport complementation. Two functionally deficient viral vectors were engineered that derive from foxtail mosaic potexvirus and sunn-hemp mosaic tobamovirus, namely FECT (FoMV Eliminate CP and TGB, (Liu and Kearney, 2010)) and SHEC (SHMV Eliminate CP gene, (Liu and Kearney, 2010)), respectively. FECT had all the ORFs removed except for the replicase and thus is defective for both long-distance and cell-to-cell movement. SHEC lacked only the coat protein ORF and retained the movement protein (MP) and is functional for cell-to-cell movement. When FECT and SHEC vectors were inoculated with the silencing suppressor p19 in different zones of the same leaf, FECT was enabled to express its reporter gene beyond the original inoculation zone. When FECT, SHEC, and p19 were individually inoculated in separate zones, both FECT and SHEC reporter gene expression was observed within the p19 zone, distant from the original virus inoculation points. These observations indicate that SHEC movement protein could create a trafficking network to allow viral RNAs of FECT and SHEC and p19/p19 transcript to move from cell to cell. This system provides a tool to visually monitor the movement of viruses and silencing suppressors as well as to identify the effects of individual viral components on virus movement.
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Affiliation(s)
- Yiyang Zhou
- Institute of Biomedical Studies, Baylor University, Waco, TX, USA
| | - Meron R Ghidey
- Institute of Biomedical Studies, Baylor University, Waco, TX, USA
| | - Grace Pruett
- Department of Biology, Baylor University, Waco, TX, USA
| | - Christopher M Kearney
- Institute of Biomedical Studies, Baylor University, Waco, TX, USA; Department of Biology, Baylor University, Waco, TX, USA.
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Hančinský R, Mihálik D, Mrkvová M, Candresse T, Glasa M. Plant Viruses Infecting Solanaceae Family Members in the Cultivated and Wild Environments: A Review. PLANTS 2020; 9:plants9050667. [PMID: 32466094 PMCID: PMC7284659 DOI: 10.3390/plants9050667] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 12/01/2022]
Abstract
Plant viruses infecting crop species are causing long-lasting economic losses and are endangering food security worldwide. Ongoing events, such as climate change, changes in agricultural practices, globalization of markets or changes in plant virus vector populations, are affecting plant virus life cycles. Because farmer’s fields are part of the larger environment, the role of wild plant species in plant virus life cycles can provide information about underlying processes during virus transmission and spread. This review focuses on the Solanaceae family, which contains thousands of species growing all around the world, including crop species, wild flora and model plants for genetic research. In a first part, we analyze various viruses infecting Solanaceae plants across the agro-ecological interface, emphasizing the important role of virus interactions between the cultivated and wild zones as global changes affect these environments on both local and global scales. To cope with these changes, it is necessary to adjust prophylactic protection measures and diagnostic methods. As illustrated in the second part, a complex virus research at the landscape level is necessary to obtain relevant data, which could be overwhelming. Based on evidence from previous studies we conclude that Solanaceae plant communities can be targeted to address complete life cycles of viruses with different life strategies within the agro-ecological interface. Data obtained from such research could then be used to improve plant protection methods by taking into consideration environmental factors that are impacting the life cycles of plant viruses.
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Affiliation(s)
- Richard Hančinský
- Faculty of Natural Sciences, University of Ss. Cyril and Methodius, Nám. J. Herdu 2, 91701 Trnava, Slovakia; (R.H.); (D.M.); (M.M.)
| | - Daniel Mihálik
- Faculty of Natural Sciences, University of Ss. Cyril and Methodius, Nám. J. Herdu 2, 91701 Trnava, Slovakia; (R.H.); (D.M.); (M.M.)
- Institute of High Mountain Biology, University of Žilina, Univerzitná 8215/1, 01026 Žilina, Slovakia
- National Agricultural and Food Centre, Research Institute of Plant Production, Bratislavská cesta 122, 92168 Piešťany, Slovakia
| | - Michaela Mrkvová
- Faculty of Natural Sciences, University of Ss. Cyril and Methodius, Nám. J. Herdu 2, 91701 Trnava, Slovakia; (R.H.); (D.M.); (M.M.)
| | - Thierry Candresse
- INRAE, University Bordeaux, UMR BFP, 33140 Villenave d’Ornon, France;
| | - Miroslav Glasa
- Faculty of Natural Sciences, University of Ss. Cyril and Methodius, Nám. J. Herdu 2, 91701 Trnava, Slovakia; (R.H.); (D.M.); (M.M.)
- Biomedical Research Center of the Slovak Academy of Sciences, Institute of Virology, Dúbravská cesta 9, 84505 Bratislava, Slovakia
- Correspondence: ; Tel.: +421-2-5930-2447
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Sungsuwan S, Jongkaewwattana A, Jaru-Ampornpan P. Nucleocapsid proteins from other swine enteric coronaviruses differentially modulate PEDV replication. Virology 2019; 540:45-56. [PMID: 31756532 PMCID: PMC7112109 DOI: 10.1016/j.virol.2019.11.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 01/08/2023]
Abstract
Porcine epidemic diarrhea virus (PEDV), transmissible gastroenteritis virus (TGEV) and porcine deltacoronavirus (PDCoV) share tropism for swine intestinal epithelial cells. Whether mixing of viral components during co-infection alters pathogenic outcomes or viral replication is not known. In this study, we investigated how different coronavirus nucleocapsid (CoV N) proteins interact and affect PEDV replication. We found that PDCoV N and TGEV N can competitively interact with PEDV N. However, the presence of PDCoV or TGEV N led to very different outcomes on PEDV replication. While PDCoV N significantly suppresses PEDV replication, overexpression of TGEV N, like that of PEDV N, increases production of PEDV RNA and virions. Despite partial interchangeability in nucleocapsid oligomerization and viral RNA synthesis, endogenous PEDV N cannot be replaced in the production of infectious PEDV particles. Results from this study give insights into functional compatibilities and evolutionary relationship between CoV viral proteins during viral co-infection and co-evolution. PDCoV N and TGEV N interact with PEDV N in a competitive, RNA-dependent manner. PEDV replication in cell culture is enhanced by overexpression of TGEV or PEDV N but strongly suppressed by that of PDCoV N. Both TGEV and PDCoV N can partially rescue viral RNA and protein synthesis functions of PEDV N, albeit to different degrees. Neither TGEV nor PDCoV N can completely replace PEDV N in the production of PEDV infectious virions.
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Affiliation(s)
- Suttipun Sungsuwan
- Virology and Cell Technology Research Team, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, 12120, Thailand
| | - Anan Jongkaewwattana
- Virology and Cell Technology Research Team, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, 12120, Thailand
| | - Peera Jaru-Ampornpan
- Virology and Cell Technology Research Team, National Center for Genetic Engineering and Biotechnology (BIOTEC), National Science and Technology Development Agency (NSTDA), Pathum Thani, 12120, Thailand.
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Olaya C, Adhikari B, Raikhy G, Cheng J, Pappu HR. Identification and localization of Tospovirus genus-wide conserved residues in 3D models of the nucleocapsid and the silencing suppressor proteins. Virol J 2019; 16:7. [PMID: 30634979 PMCID: PMC6330412 DOI: 10.1186/s12985-018-1106-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 10/16/2018] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Tospoviruses (genus Tospovirus, family Peribunyaviridae, order Bunyavirales) cause significant losses to a wide range of agronomic and horticultural crops worldwide. Identification and characterization of specific sequences and motifs that are critical for virus infection and pathogenicity could provide useful insights and targets for engineering virus resistance that is potentially both broad spectrum and durable. Tomato spotted wilt virus (TSWV), the most prolific member of the group, was used to better understand the structure-function relationships of the nucleocapsid gene (N), and the silencing suppressor gene (NSs), coded by the TSWV small RNA. METHODS Using a global collection of orthotospoviral sequences, several amino acids that were conserved across the genus and the potential location of these conserved amino acid motifs in these proteins was determined. We used state of the art 3D modeling algorithms, MULTICOM-CLUSTER, MULTICOM-CONSTRUCT, MULTICOM-NOVEL, I-TASSER, ROSETTA and CONFOLD to predict the secondary and tertiary structures of the N and the NSs proteins. RESULTS We identified nine amino acid residues in the N protein among 31 known tospoviral species, and ten amino acid residues in NSs protein among 27 tospoviral species that were conserved across the genus. For the N protein, all three algorithms gave nearly identical tertiary models. While the conserved residues were distributed throughout the protein on a linear scale, at the tertiary level, three residues were consistently located in the coil in all the models. For NSs protein models, there was no agreement among the three algorithms. However, with respect to the localization of the conserved motifs, G18 was consistently located in coil, while H115 was localized in the coil in three models. CONCLUSIONS This is the first report of predicting the 3D structure of any tospoviral NSs protein and revealed a consistent location for two of the ten conserved residues. The modelers used gave accurate prediction for N protein allowing the localization of the conserved residues. Results form the basis for further work on the structure-function relationships of tospoviral proteins and could be useful in developing novel virus control strategies targeting the conserved residues.
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Affiliation(s)
- Cristian Olaya
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA
| | - Badri Adhikari
- Department of Mathematics and Computer Science, University of Missouri, St. Louis, MO, 63121, USA
| | - Gaurav Raikhy
- Department of Microbiology and Immunology, Louisiana State University, Shreverport, LA, 71101, USA
| | - Jianlin Cheng
- Department of Electrical Engineering and Computer Science, University of Missouri, Columbia, MO, 65211, USA
| | - Hanu R Pappu
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA.
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Varanda CM, Materatski P, Campos MD, Clara MIE, Nolasco G, Félix MDR. Olive Mild Mosaic Virus Coat Protein and P6 Are Suppressors of RNA Silencing, and Their Silencing Confers Resistance against OMMV. Viruses 2018; 10:E416. [PMID: 30096871 PMCID: PMC6115721 DOI: 10.3390/v10080416] [Citation(s) in RCA: 8] [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: 06/18/2018] [Revised: 08/03/2018] [Accepted: 08/06/2018] [Indexed: 12/16/2022] Open
Abstract
RNA silencing is an important defense mechanism in plants, yet several plant viruses encode proteins that suppress this mechanism. In this study, the genome of the Olive mild mosaic virus (OMMV) was screened for silencing suppressors. The full OMMV cDNA and 5 OMMV open reading frames (ORFs) were cloned into the Gateway binary vector pK7WG2, transformed into Agrobacterium tumefaciens, and agroinfiltrated into N. benthamiana 16C plants. CP and p6 showed suppressor activity, with CP showing significantly higher activity than p6, yet activity that was lower than the full OMMV, suggesting a complementary action of CP and p6. These viral suppressors were then used to induce OMMV resistance in plants based on RNA silencing. Two hairpin constructs targeting each suppressor were agroinfiltrated in N. benthamiana plants, which were then inoculated with OMMV RNA. When silencing of both suppressors was achieved, a significant reduction in viral accumulation and symptom attenuation was observed as compared to those of the controls, as well as to when each construct was used alone, proving them to be effective against OMMV infection. This is the first time that a silencing suppressor was found in a necrovirus, and that two independent proteins act as silencing suppressors in a virus member of the Tombusviridae family.
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Affiliation(s)
- Carla Mr Varanda
- ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Instituto de Investigação e Formação Avançada, Universidade de Évora, Pólo da Mitra, Ap.94, 7006-554 Évora, Portugal.
| | - Patrick Materatski
- ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Instituto de Investigação e Formação Avançada, Universidade de Évora, Pólo da Mitra, Ap.94, 7006-554 Évora, Portugal.
| | - Maria Doroteia Campos
- ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Instituto de Investigação e Formação Avançada, Universidade de Évora, Pólo da Mitra, Ap.94, 7006-554 Évora, Portugal.
| | - Maria Ivone E Clara
- Departamento de Fitotecnia, ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Escola de Ciências e Tecnologia, Universidade de Évora, Pólo da Mitra, Ap.94, 7006-554 Évora, Portugal.
| | - Gustavo Nolasco
- MeditBio-Centro para os Recursos Biológicos e Alimentos Mediterrânicos, Faculdade de Ciências e Tecnologia, Universidade do Algarve, Campus de Gambelas, 8005-139 Faro, Portugal.
| | - Maria do Rosário Félix
- Departamento de Fitotecnia, ICAAM-Instituto de Ciências Agrárias e Ambientais Mediterrânicas, Escola de Ciências e Tecnologia, Universidade de Évora, Pólo da Mitra, Ap.94, 7006-554 Évora, Portugal.
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Tomato Spotted Wilt Virus NSs Protein Supports Infection and Systemic Movement of a Potyvirus and Is a Symptom Determinant. Viruses 2018. [PMID: 29538326 PMCID: PMC5869522 DOI: 10.3390/v10030129] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Plant viruses are inducers and targets of antiviral RNA silencing. To condition susceptibility, most plant viruses encode silencing suppressor proteins that interfere with antiviral RNA silencing. The NSs protein is an RNA silencing suppressor in orthotospoviruses, such as the tomato spotted wilt virus (TSWV). The mechanism of RNA silencing suppression by NSs and its role in virus infection and movement are poorly understood. Here, we cloned and tagged TSWV NSs and expressed it from a GFP-tagged turnip mosaic virus (TuMV-GFP) carrying either a wild-type or suppressor-deficient (AS9) helper component proteinase (HC-Pro). When expressed in cis, NSs restored pathogenicity and promoted systemic infection of suppressor-deficient TuMV-AS9-GFP in Nicotiana benthamiana and Arabidopsis thaliana. Inactivating mutations were introduced in NSs RNA-binding domain one. A genetic analysis with active and suppressor-deficient NSs, in combination with wild-type and mutant plants lacking essential components of the RNA silencing machinery, showed that the NSs insert is stable when expressed from a potyvirus. NSs can functionally replace potyviral HC-Pro, condition virus susceptibility, and promote systemic infection and symptom development by suppressing antiviral RNA silencing through a mechanism that partially overlaps that of potyviral HC-Pro. The results presented provide new insight into the mechanism of silencing suppression by NSs and its effect on virus infection.
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Bag S, Schwartz HF, Cramer CS, Havey MJ, Pappu HR. Iris yellow spot virus (Tospovirus: Bunyaviridae): from obscurity to research priority. MOLECULAR PLANT PATHOLOGY 2015; 16:224-37. [PMID: 25476540 PMCID: PMC6638421 DOI: 10.1111/mpp.12177] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
TAXONOMY Iris yellow spot virus (IYSV) is in the genus Tospovirus, family Bunyaviridae, with a single-stranded, tri-segmented RNA genome with an ambisense genome organization. Members of the other genera in the family infect predominantly vertebrates and insects. GEOGRAPHICAL DISTRIBUTION IYSV is present in most Allium-growing regions of the world. PHYSICAL PROPERTIES Virions are pleomorphic particles of 80-120 nm in size. The particle consists of RNA, protein, glycoprotein and lipids. GENOME IYSV shares the genomic features of other tospoviruses: a segmented RNA genome of three RNAs, referred to as large (L), medium (M) and small (S). The L RNA codes for the RNA-dependent RNA polymerase (RdRp) in negative sense. The M RNA uses an ambisense coding strategy and codes for the precursor for the GN /GC glycoprotein in the viral complementary (vc) sense and a non-structural protein (NSm) in the viral (v) sense. The S RNA also uses an ambisense coding strategy with the coat protein (N) in vc sense and a non-structural protein (NSs) in the v sense. TRANSMISSION The virus is transmitted by Thrips tabaci Lindeman (Order: Thysanoptera; Family: Thripidae; onion thrips) and with less efficiency by Frankliniella fusca Hinds (tobacco thrips). HOST: IYSV has a relatively broad host range, including cultivated and wild onions, garlic, chives, leeks and several ornamentals. Some weeds are naturally infected by IYSV and may serve as alternative hosts for the virus. SYMPTOMS IYSV symptoms in Allium spp. are yellow- to straw-coloured, diamond-shaped lesions on leaves and flowering scapes. Diamond-shaped lesions are particularly pronounced on scapes. As the disease progresses, the lesions coalesce, leading to lodging of the scapes. In seed crops, this could lead to a reduction in yield and quality. Early to mid-season infection in bulb crops results in reduced vigour and bulb size. CONTROL Resistant varieties are not available, but a limited number of accessions with field tolerance have been identified. Integrated disease management tactics, including sanitation, crop rotation, thrips management, maintenance of optimal plant vigour, soil fertility, irrigation and physical separation of bulb and seed crops, can mitigate the effect of the disease. Virus code: 00.011.0.85.009 Useful link: http://www.alliumnet.com/.
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Affiliation(s)
- Sudeep Bag
- Department of Plant Pathology, Washington State University, Pullman, WA, 99164, USA
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Leastro M, Pallás V, Resende R, Sánchez-Navarro J. The movement proteins (NSm) of distinct tospoviruses peripherally associate with cellular membranes and interact with homologous and heterologous NSm and nucleocapsid proteins. Virology 2015; 478:39-49. [DOI: 10.1016/j.virol.2015.01.031] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2014] [Revised: 01/06/2015] [Accepted: 01/31/2015] [Indexed: 01/26/2023]
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Tripathi D, Raikhy G, Pappu HR. Movement and nucleocapsid proteins coded by two tospovirus species interact through multiple binding regions in mixed infections. Virology 2015; 478:137-47. [PMID: 25666522 DOI: 10.1016/j.virol.2015.01.009] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2014] [Revised: 12/07/2014] [Accepted: 01/10/2015] [Indexed: 12/31/2022]
Abstract
Negative-stranded tospoviruses (family: Bunyaviridae) are among the most agronomically important viruses. Some of the tospoviruses are known to exist as mixed infections in the same host plant. Iris yellow spot virus (IYSV) and Tomato spotted wilt virus (TSWV) were used to study virus-virus interaction in dually infected host plants. Viral genes of both viruses were separately cloned into binary pSITE-BiFC vectors. BiFC results showed that the N and NSm proteins of IYSV interact with their counterparts coded by TSWV in dually infected Nicotiana benthamiana plants. BiFC results were further confirmed by pull down and yeast-2-hybrid (Y2H) assays. Interacting regions of the N and NSm proteins were also identified by Y2H system and β-galactosidase activity. Several regions of the N and NSm were found interacting with each other. The regions involved in these interactions are presumed to be critical for the functioning of the tospovirus N and NSm proteins. This is the first report of in vivo protein interactions of distinct tospoviruses in mixed infection.
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Affiliation(s)
- Diwaker Tripathi
- Department of Plant Pathology, Washington State University, P.O. Box 646430, Pullman, WA 99164-6430, USA
| | - Gaurav Raikhy
- Department of Plant Pathology, Washington State University, P.O. Box 646430, Pullman, WA 99164-6430, USA
| | - Hanu R Pappu
- Department of Plant Pathology, Washington State University, P.O. Box 646430, Pullman, WA 99164-6430, USA.
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Morales K, Zambrano JL, Stewart LR. Co-infection and Disease Severity of Ohio Maize dwarf mosaic virus and Maize chlorotic dwarf virus Strains. PLANT DISEASE 2014; 98:1661-1665. [PMID: 30703876 DOI: 10.1094/pdis-12-13-1230-re] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Two major maize viruses have been reported in the United States: Maize dwarf mosaic virus (MDMV) and Maize chlorotic dwarf virus (MCDV). These viruses co-occur in regions where maize is grown, such that co-infections are likely. Co-infection of different strains of MCDV is also observed, and a synergistic enhancement of symptoms in co-infected plants was previously reported. Here, we examined the impact of co-infections of two strains of MCDV (MCDV-S and MCDV-M1, severe and mild, respectively), and co-infections of MCDV and MDMV in the sweet corn hybrid 'Spirit' in greenhouse experiments. Quantitative plant growth and development parameters were measured and virus accumulation was measured by reverse-transcriptase quantitative polymerase chain reaction. Virus symptoms were enhanced and plants showed no recovery over time in co-infections of MDMV-OH and MCDV-S but virus titers and quantitative growth parameters did not indicate synergy in co-infected plants. MCDV-M1 co-infections with either MDMV-OH or MCDV-S did not show symptom enhancement or evidence of synergism.
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Affiliation(s)
- Katia Morales
- United States Department of Agriculture-Agricultural Research Service (USDA-ARS) Corn, Soybean, and Wheat Quality Research Unit, Ohio Agricultural Research and Development Center, Wooster, OH
| | - Jose Luis Zambrano
- Instituto Nacional Autónomo de Investigaciones Agropecuarias, INIAP, Programa Nacional de Maíz, Quito, Ecuador; and Ohio State University Department of Plant Pathology, Ohio Agricultural Research and Development Center, Wooster
| | - Lucy R Stewart
- USDA-ARS Corn, Soybean, and Wheat Quality Research Unit and Ohio State University Department of Plant Pathology, Ohio Agricultural Research and Development Center
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Zhai Y, Bag S, Mitter N, Turina M, Pappu HR. Mutational analysis of two highly conserved motifs in the silencing suppressor encoded by tomato spotted wilt virus (genus Tospovirus, family Bunyaviridae). Arch Virol 2014; 159:1499-504. [PMID: 24363189 DOI: 10.1007/s00705-013-1928-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Accepted: 11/14/2013] [Indexed: 10/25/2022]
Abstract
Tospoviruses cause serious economic losses to a wide range of field and horticultural crops on a global scale. The NSs gene encoded by tospoviruses acts as a suppressor of host plant defense. We identified amino acid motifs that are conserved in all of the NSs proteins of tospoviruses for which the sequence is known. Using tomato spotted wilt virus (TSWV) as a model, the role of these motifs in suppressor activity of NSs was investigated. Using site-directed point mutations in two conserved motifs, glycine, lysine and valine/threonine (GKV/T) at positions 181-183 and tyrosine and leucine (YL) at positions 412-413, and an assay to measure the reversal of gene silencing in Nicotiana benthamiana line 16c, we show that substitutions (K182 to A, and L413 to A) in these motifs abolished suppressor activity of the NSs protein, indicating that these two motifs are essential for the RNAi suppressor function of tospoviruses.
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Affiliation(s)
- Ying Zhai
- Department of Plant Pathology, Washington State University, PO Box 646430, Pullman, WA, 99164, USA
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Non-coding RNAs in crop genetic modification: considerations and predictable environmental risk assessments (ERA). Mol Biotechnol 2014; 55:87-100. [PMID: 23381873 DOI: 10.1007/s12033-013-9648-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Of late non-coding RNAs (ncRNAs)-mediated gene silencing is an influential tool deliberately deployed to negatively regulate the expression of targeted genes. In addition to the widely employed small interfering RNA (siRNA)-mediated gene silencing approach, other variants like artificial miRNA (amiRNA), miRNA mimics, and artificial transacting siRNAs (tasiRNAs) are being explored and successfully deployed in developing non-coding RNA-based genetically modified plants. The ncRNA-based gene manipulations are typified with mobile nature of silencing signals, interference from viral genome-derived suppressor proteins, and an obligation for meticulous computational analysis to prevaricate any inadvertent effects. In a broad sense, risk assessment inquiries for genetically modified plants based on the expression of ncRNAs are competently addressed by the environmental risk assessment (ERA) models, currently in vogue, designed for the first generation transgenic plants which are based on the expression of heterologous proteins. Nevertheless, transgenic plants functioning on the foundation of ncRNAs warrant due attention with respect to their unique attributes like off-target or non-target gene silencing effects, small RNAs (sRNAs) persistence, food and feed safety assessments, problems in detection and tracking of sRNAs in food, impact of ncRNAs in plant protection measures, effect of mutations etc. The role of recent developments in sequencing techniques like next generation sequencing (NGS) and the ERA paradigm of the different countries in vogue are also discussed in the context of ncRNA-based gene manipulations.
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Abstract
The number of virus species infecting pepper (Capsicum spp.) crops and their incidences has increased considerably over the past 30 years, particularly in tropical and subtropical pepper production systems. This is probably due to a combination of factors, including the expansion and intensification of pepper cultivation in these regions, the increased volume and speed of global trade of fresh produce (including peppers) carrying viruses and vectors to new locations, and perhaps climate change expanding the geographic range suitable for the viruses and vectors. With the increased incidences of diverse virus species comes increased incidences of coinfection with two or more virus species in the same plant. There is then greater chance of synergistic interactions between virus species, increasing symptom severity and weakening host resistance, as well as the opportunity for genetic recombination and component exchange and a possible increase in aggressiveness, virulence, and transmissibility. The main virus groups infecting peppers are transmitted by aphids, whiteflies, or thrips, and a feature of many populations of these vector groups is that they can develop resistance to some of the commonly used insecticides relatively quickly. This, coupled with the increasing concern over the impact of over- or misuse of insecticides on the environment, growers, and consumers, means that there should be less reliance on insecticides to control the vectors of viruses infecting pepper crops. To improve the durability of pepper crop protection measures, there should be a shift away from the broadscale use of insecticides and the use of single, major gene resistance to viruses. Instead, integrated and pragmatic virus control measures should be sought that combine (1) cultural practices that reduce sources of virus inoculum and decrease the rate of spread of viruliferous vectors into the pepper crop, (2) synthetic insecticides, which should be used judiciously and only when the plants are young and most susceptible to infection, (3) appropriate natural products and biocontrol agents to induce resistance in the plants, affect the behavior of the vector insects, or augment the local populations of parasites or predators of the virus vectors, and (4) polygenic resistances against viruses and vector insects with pyramided single-gene virus resistances to improve resistance durability.
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