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Ng JCK, Peng JHC, Chen AYS, Tian T, Zhou JS, Smith TJ. Plasticity of the lettuce infectious yellows virus minor coat protein (CPm) in mediating the foregut retention and transmission of a chimeric CPm mutant by whitefly vectors. J Gen Virol 2021; 102:001652. [PMID: 34494949 PMCID: PMC8567426 DOI: 10.1099/jgv.0.001652] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/16/2021] [Indexed: 01/04/2023] Open
Abstract
Transmission of the crinivirus, lettuce infectious yellows virus (LIYV), is determined by a minor coat protein (CPm)-mediated virion retention mechanism located in the foregut of its whitefly vector. To better understand the functions of LIYV CPm, chimeric CPm mutants engineered with different lengths of the LIYV CPm amino acid sequence and that of the crinivirus, lettuce chlorosis virus (LCV), were constructed based on bioinformatics and sequence alignment data. The 485 amino acid-long chimeric CPm of LIYV mutant, CPmP-1, contains 60 % (from position 3 to 294) of LCV CPm amino acids. The chimeric CPm of mutants CPmP-2, CPmP-3 and CPmP-4 contains 46 (position 3 to 208), 51 (position 3 to 238) and 41 % (position 261 to 442) of LCV CPm amino acids, respectively. All four mutants moved systemically, expressed the chimeric CPm and formed virus particles. However, following acquisition feeding of the virus preparations, only CPmP-1 was retained in the foreguts of a significant number of vectors and transmitted. In immuno-gold labelling transmission electron microscopy (IGL-TEM) analysis, CPmP-1 particles were distinctly labelled by antibodies directed against the LCV but not LIYV CPm. In contrast, CPmP-4 particles were not labelled by antibodies directed against the LCV or LIYV CPm, while CPmP-2 and -3 particles were weakly labelled by anti-LIYV CPm but not anti-LCV CPm antibodies. The unique antibody recognition and binding pattern of CPmP-1 was also displayed in the foreguts of whitefly vectors that fed on CPmP-1 virions. These results are consistent with the hypothesis that the chimeric CPm of CPmP-1 is incorporated into functional virions, with the LCV CPm region being potentially exposed on the surface and accessible to anti-LCV CPm antibodies.
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Affiliation(s)
- James C. K. Ng
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, USA
- Center for Infectious Disease and Vector Research, University of California, Riverside, CA 92521, USA
| | - James H. C. Peng
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, USA
| | - Angel Y. S. Chen
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, USA
| | - Tongyan Tian
- California Department of Food and Agriculture, Sacramento, CA 95832, USA
| | - Jaclyn S. Zhou
- Department of Microbiology and Plant Pathology, University of California, Riverside, CA 92521, USA
| | - Thomas J. Smith
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, TX, 77555, USA
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Yang H, Zu G, Liu Y, Xie D, Gan X, Song B. Tomato Chlorosis Virus Minor Coat Protein as a Novel Target To Screen Antiviral Drugs. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:3425-3433. [PMID: 32091891 DOI: 10.1021/acs.jafc.9b08215] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Minor coat protein (mCP), an important component of tomato chlorosis virus (ToCV), plays a significant role in the process of virus assembly and movement and is directly related to the virus-insect transmission. Therefore, ToCV mCP could be considered as a potent target for anti-ToCV drugs. In this study, ToCV mCP was first cloned, expressed, purified, and a novel target to screen the antiviral agents. The results showed that some antiviral compounds bound to ToCV mCP with strongly affinities in vitro, including quinazoline derivatives 4a and 4b, Ningnanmycin, and Ribavirin. Subsequently, three-dimensional-quantitative structure-activity relationship (3D-QSAR) analysis was performed based on the binding affinities, and the model indicated that 4a and 4b had indeed stronger binding effects on ToCV mCP than other quinazoline derivatives. Finally, the anti-ToCV activities of compounds 4a and 4b were evaluated by quantitative real-time polymerase chain reaction in vivo. Compounds 4a and 4b inhibited infection of ToCV in the host and as well as reduced the level of ToCV mCP gene expression. Thus, ToCV mCP can be used as a novel drug target for screening anti-ToCV agents, and the ligand-based 3D-QSAR analysis of quinazoline derivatives provided new insights into the design and optimization of novel anti-ToCV drug molecules based on ToCV mCP.
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Affiliation(s)
- Huanyu Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Guangcheng Zu
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Yuewen Liu
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Dandan Xie
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Xiuhai Gan
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
| | - Baoan Song
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Guizhou University, Huaxi District, Guiyang 550025, China
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Kaur N, Chen W, Fei Z, Wintermantel WM. Differences in gene expression in whitefly associated with CYSDV-infected and virus-free melon, and comparison with expression in whiteflies fed on ToCV- and TYLCV-infected tomato. BMC Genomics 2019; 20:654. [PMID: 31416422 PMCID: PMC6694564 DOI: 10.1186/s12864-019-5999-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Accepted: 07/26/2019] [Indexed: 01/31/2023] Open
Abstract
Background Cucurbit yellow stunting disorder virus (CYSDV; genus Crinivirus, Closteroviridae) is transmitted in a semipersistent manner by the whitefly, Bemisia tabaci, and is efficiently transmitted by the widely prevalent B. tabaci cryptic species, MEAM1. In this study, we compared transcriptome profiles of B. tabaci MEAM1, after 24 h, 72 h and 7 days of acquisition feeding on melon plants infected with CYSDV (CYSDV-whiteflies) with those fed on virus-free melon, using RNA-Seq technology. We also compared transcriptome profiles with whiteflies fed on tomato plants separately infected with Tomato chlorosis virus (ToCV), a crinivirus closely related to CYSDV, and Tomato yellow leaf curl virus (TYLCV), a member of the genus Begomovirus, which has a distinctly different mode of transmission and their respective virus-free controls, to find common gene expression changes among viruliferous whiteflies feeding on different host plants infected with distinct (TYLCV) and related (CYSDV and ToCV) viruses. Results A total of 275 differentially expressed genes (DEGs) were identified in CYSDV-whiteflies, with 3 DEGs at 24 h, 221 DEGs at 72 h, and 51 DEGs at 7 days of virus acquisition. Changes in genes encoding orphan genes (54 genes), phosphatidylethanolamine-binding proteins (PEBP) (20 genes), and AAA-ATPase domain containing proteins (10 genes) were associated with the 72 h time point. Several more orphan genes (20 genes) were differentially expressed at 7 days. A total of 59 common DEGs were found between CYSDV-whiteflies and ToCV-whiteflies, which included 20 orphan genes and 6 lysosomal genes. A comparison of DEGs across the three different virus-host systems revealed 14 common DEGs, among which, eight showed similar and significant up-regulation in CYSDV-whiteflies at 72 h and TYLCV-whiteflies at 24 h, while down-regulation of the same genes was observed in ToCV-whiteflies at 72 h. Conclusions Dynamic gene expression changes occurred in CYSDV-whiteflies after 72 h feeding, with decreased gene expression changes associated with 7 days of CYSDV acquisition. Similarities in gene expression changes among CYSDV-whiteflies, ToCV-whiteflies and TYLCV-whiteflies suggest the possible involvement of common genes or pathways for virus acquisition and transmission by whiteflies, even for viruses with distinctly different modes of transmission. Electronic supplementary material The online version of this article (10.1186/s12864-019-5999-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Navneet Kaur
- USDA-ARS, Crop Improvement and Protection Research, 1636 East Alisal Street, Salinas, CA, 93905, USA.,Present Address: Driscoll's Inc., 151 Silliman Rd., Watsonville, CA, 95076, USA
| | - Wenbo Chen
- Boyce Thompson Institute, 533 Tower Road, Ithaca, New York, 14853-1801, USA
| | - Zhangjun Fei
- Boyce Thompson Institute, 533 Tower Road, Ithaca, New York, 14853-1801, USA.,USDA-ARS, Robert W. Holley Center for Agriculture and Health, 538 Tower Road, Ithaca, New York, 14853-2901, USA
| | - William M Wintermantel
- USDA-ARS, Crop Improvement and Protection Research, 1636 East Alisal Street, Salinas, CA, 93905, USA.
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Navarro JA, Sanchez-Navarro JA, Pallas V. Key checkpoints in the movement of plant viruses through the host. Adv Virus Res 2019; 104:1-64. [PMID: 31439146 DOI: 10.1016/bs.aivir.2019.05.001] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Plant viruses cannot exploit any of the membrane fusion-based routes of entry described for animal viruses. In addition, one of the distinctive structures of plant cells, the cell wall, acts as the first barrier against the invasion of pathogens. To overcome the rigidity of the cell wall, plant viruses normally take advantage of the way of life of different biological vectors. Alternatively, the physical damage caused by environmental stresses can facilitate virus entry. Once inside the cell and taking advantage of the characteristic symplastic continuity of plant cells, viruses need to remodel and/or modify the restricted pore size of the plasmodesmata (channels that connect plant cells). In a successful interaction for the virus, it can reach the vascular tissue to systematically invade the plant. The connections between the different cell types in this path are not designed to allow the passage of molecules with the complexity of viruses. During this process, viruses face different cell barriers that must be overcome to reach the distal parts of the plant. In this review, we highlight the current knowledge about how plant RNA viruses enter plant cells, move between them to reach vascular cells and overcome the different physical and cellular barriers that the phloem imposes. Finally, we update the current research on cellular organelles as key regulator checkpoints in the long-distance movement of plant viruses.
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Affiliation(s)
- Jose A Navarro
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Jesus A Sanchez-Navarro
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain
| | - Vicente Pallas
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Universidad Politécnica de Valencia-Consejo Superior de Investigaciones Científicas, Valencia, Spain.
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Zhou JS, Chen AYS, Drucker M, Lopez NH, Carpenter A, Ng JCK. Whitefly feeding behavior and retention of a foregut-borne crinivirus exposed to artificial diets with different pH values. INSECT SCIENCE 2017; 24:1079-1092. [PMID: 28677320 DOI: 10.1111/1744-7917.12503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 06/08/2017] [Accepted: 06/21/2017] [Indexed: 06/07/2023]
Abstract
Transmission of plant viruses by phytophagous hemipteran insects encompasses complex interactions underlying a continuum of processes involved in virus acquisition, retention and inoculation combined with vector feeding behavior. Here, we investigated the effects of dietary pH on whitefly (Bemisia tabaci) feeding behavior and release of Lettuce infectious yellows virus (LIYV) virions retained in the vector's foregut. Electrical penetration graph analysis revealed that variables associated with whitefly probing and ingestion did not differ significantly in pH (4, 7.4, and 9) adjusted artificial diets. To investigate virus retention and release, whiteflies allowed to acquire LIYV virions in a pH 7.4 artificial diet were fed pH 4, 7.4, or 9 virion-free artificial (clearing) diets. Immunofluorescent localization analyses indicated that virions remained bound to the foreguts of approximately 20%-24% of vectors after they fed on each of the 3 pH-adjusted clearing diets. When RNA preparations from the clearing diets were analyzed by reverse transcription (RT) nested-PCR and, in some cases, real-time qPCR, successful amplification of LIYV-specific sequence was infrequent but consistently repeatable for the pH 7.4 diet but never observed for the pH 4 and 9 diets, suggesting a weak pH-dependent effect for virion release. Viruliferous vectors that fed on each of the 3 pH-adjusted clearing diets transmitted LIYV to virus-free plants. These results suggest that changes in pH values alone in artificial diet do not result in observable changes in whitefly feeding behaviors, an observation that marks a first in the feeding of artificial diet by whitefly vectors; and that there is a potential causal and contingent relationship between the pH in artificial diet and the release/inoculation of foregut bound virions.
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Affiliation(s)
- Jaclyn S Zhou
- Department of Plant Pathology and Microbiology, and Center for Disease Vector Research, University of California, Riverside, California, USA
| | - Angel Y S Chen
- Department of Plant Pathology and Microbiology, and Center for Disease Vector Research, University of California, Riverside, California, USA
| | - Martin Drucker
- INRA, UMR BGPI Plant Pathogen Interactions, Montpellier Cedex 5, France
| | | | | | - James C K Ng
- Department of Plant Pathology and Microbiology, and Center for Disease Vector Research, University of California, Riverside, California, USA
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Kaur N, Chen W, Zheng Y, Hasegawa DK, Ling KS, Fei Z, Wintermantel WM. Transcriptome analysis of the whitefly, Bemisia tabaci MEAM1 during feeding on tomato infected with the crinivirus, Tomato chlorosis virus, identifies a temporal shift in gene expression and differential regulation of novel orphan genes. BMC Genomics 2017; 18:370. [PMID: 28494755 PMCID: PMC5426028 DOI: 10.1186/s12864-017-3751-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 05/02/2017] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Whiteflies threaten agricultural crop production worldwide, are polyphagous in nature, and transmit hundreds of plant viruses. Little is known how whitefly gene expression is altered due to feeding on plants infected with a semipersistently transmitted virus. Tomato chlorosis virus (ToCV; genus Crinivirus, family Closteroviridae) is transmitted by the whitefly (Bemisia tabaci) in a semipersistent manner and infects several globally important agricultural and ornamental crops, including tomato. RESULTS To determine changes in global gene regulation in whiteflies after feeding on tomato plants infected with a crinivirus (ToCV), comparative transcriptomic analysis was performed using RNA-Seq on whitefly (Bemisia tabaci MEAM1) populations after 24, 48, and 72 h acquisition access periods on either ToCV-infected or uninfected tomatoes. Significant differences in gene expression were detected between whiteflies fed on ToCV-infected tomato and those fed on uninfected tomato among the three feeding time periods: 447 up-regulated and 542 down-regulated at 24 h, 4 up-regulated and 7 down-regulated at 48 h, and 50 up-regulated and 160 down-regulated at 72 h. Analysis revealed differential regulation of genes associated with metabolic pathways, signal transduction, transport and catabolism, receptors, glucose transporters, α-glucosidases, and the uric acid pathway in whiteflies fed on ToCV-infected tomatoes, as well as an abundance of differentially regulated novel orphan genes. Results demonstrate for the first time, a specific and temporally regulated response by the whitefly to feeding on a host plant infected with a semipersistently transmitted virus, and advance the understanding of the whitefly vector-virus interactions that facilitate virus transmission. CONCLUSION Whitefly transmission of semipersistent viruses is believed to require specific interactions between the virus and its vector that allow binding of virus particles to factors within whitefly mouthparts. Results provide a broader understanding of the potential mechanism of crinivirus transmission by whitefly, aid in discerning genes or loci in whitefly that influence virus interactions or transmission, and subsequently facilitate development of novel, genetics-based control methods against whitefly and whitefly-transmitted viruses.
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Affiliation(s)
- Navneet Kaur
- USDA-ARS, Crop Improvement and Protection Research, 1636 East Alisal Street, Salinas, CA 93905 USA
| | - Wenbo Chen
- Boyce Thompson Institute, 533 Tower Road, Ithaca, NY 14853-1801 USA
| | - Yi Zheng
- Boyce Thompson Institute, 533 Tower Road, Ithaca, NY 14853-1801 USA
| | - Daniel K. Hasegawa
- USDA-ARS, U.S. Vegetable Laboratory, Charleston, 2700 Savannah Highway, Charleston, SC 29414 USA
| | - Kai-Shu Ling
- USDA-ARS, U.S. Vegetable Laboratory, Charleston, 2700 Savannah Highway, Charleston, SC 29414 USA
| | - Zhangjun Fei
- Boyce Thompson Institute, 533 Tower Road, Ithaca, NY 14853-1801 USA
| | - William M. Wintermantel
- USDA-ARS, Crop Improvement and Protection Research, 1636 East Alisal Street, Salinas, CA 93905 USA
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Kiss ZA, Medina V, Falk BW. Crinivirus replication and host interactions. Front Microbiol 2013; 4:99. [PMID: 23730299 PMCID: PMC3657685 DOI: 10.3389/fmicb.2013.00099] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2013] [Accepted: 04/06/2013] [Indexed: 01/01/2023] Open
Abstract
Criniviruses comprise one of the genera within the family Closteroviridae. Members in this family are restricted to the phloem and rely on whitefly vectors of the genera Bemisia and/or Trialeurodes for plant-to-plant transmission. All criniviruses have bipartite, positive-sense single-stranded RNA genomes, although there is an unconfirmed report of one having a tripartite genome. Lettuce infectious yellows virus (LIYV) is the type species of the genus, the best studied so far of the criniviruses and the first for which a reverse genetics system was developed. LIYV RNA 1 encodes for proteins predicted to be involved in replication, and alone is competent for replication in protoplasts. Replication results in accumulation of cytoplasmic vesiculated membranous structures which are characteristic of most studied members of the Closteroviridae. These membranous structures, often referred to as Beet yellows virus (BYV)-type vesicles, are likely sites of RNA replication. LIYV RNA 2 is replicated in trans when co-infecting cells with RNA 1, but is temporally delayed relative to RNA 1. Efficient RNA 2 replication also is dependent on the RNA 1-encoded RNA-binding protein, P34. No LIYV RNA 2-encoded proteins have been shown to affect RNA replication, but at least four, CP (major coat protein), CPm (minor coat protein), Hsp70h, and P59 are virion structural components and CPm is a determinant of whitefly transmissibility. Roles of other LIYV RNA 2-encoded proteins are largely as yet unknown, but P26 is a non-virion protein that accumulates in cells as characteristic plasmalemma deposits which in plants are localized within phloem parenchyma and companion cells over plasmodesmata connections to sieve elements. The two remaining crinivirus-conserved RNA 2-encoded proteins are P5 and P9. P5 is 39 amino acid protein and is encoded at the 5' end of RNA 2 as ORF 1 and is part of the hallmark closterovirus gene array. The orthologous gene in BYV has been shown to play a role in cell-to-cell movement and indicated to be localized to the endoplasmic reticulum as a Type III integral membrane protein. The other small protein, P9, is encoded by ORF 4 overlaps with ORF 3 that encodes the structural protein, P59. P9 seems to be unique to viruses in the genus Crinivirus, as no similar protein has been detected in viruses of the other two genera of the Closteroviridae.
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Affiliation(s)
- Zsofia A. Kiss
- Department of Plant Pathology, University of CaliforniaDavis, CA, USA
| | - Vicente Medina
- Department of Crop and Forest Sciences, University of LleidaLleida, Spain
| | - Bryce W. Falk
- Department of Plant Pathology, University of CaliforniaDavis, CA, USA
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Ng JCK. A Quantum Dot-Immunofluorescent Labeling Method to Investigate the Interactions between a Crinivirus and Its Whitefly Vector. Front Microbiol 2013; 4:77. [PMID: 23577009 PMCID: PMC3616251 DOI: 10.3389/fmicb.2013.00077] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 03/15/2013] [Indexed: 11/18/2022] Open
Abstract
Successful vector-mediated plant virus transmission entails an intricate but poorly understood interplay of interactions among virus, vector, and plant. The complexity of interactions requires continually improving/evaluating tools and methods for investigating the determinants that are central to mediating virus transmission. A recent study using an organic fluorophore (Alexa Fluor)-based immunofluorescent localization assay demonstrated that specific retention of Lettuce infectious yellows virus (LIYV) virions in the anterior foregut or cibarium of its whitefly vector is required for virus transmission. Continuous exposure of organic fluorophore to high excitation light intensity can result in diminished or loss of signals, potentially confounding the identification of important interactions associated with virus transmission. This limitation can be circumvented by incorporation of photostable fluorescent nanocrystals, such as quantum dots (QDs), into the assay. We have developed and evaluated a QD-immunofluorescent labeling method for the in vitro and in situ localization of LIYV virions based on the recognition specificity of streptavidin-conjugated QD605 (S-QD605) for biotin-conjugated anti-LIYV IgG (B-αIgG). IgG biotinylation was verified in a blot overlay assay by probing SDS-PAGE separated B-αIgG with S-QD605. Immunoblot analyses of LIYV using B-αIgG and S-QD605 resulted in a virus detection limit comparable to that of DAS-ELISA. In membrane feeding experiments, QD signals were observed in the anterior foregut or cibarium of virion-fed whitefly vectors but absent in those of virion-fed whitefly non-vectors. Specific virion retention in whitefly vectors corresponded with successful virus transmission. A fluorescence photobleaching assay of viruliferous whiteflies fed B-αIgG and S-QD605 vs. those fed anti-LIYV IgG and Alexa Fluor 488-conjugated IgG revealed that QD signal was stable and deteriorated approx. seven- to eight-fold slower than that of Alexa Fluor.
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Affiliation(s)
- James C. K. Ng
- Department of Plant Pathology and Microbiology, Center for Disease Vector Research, University of CaliforniaRiverside, CA, USA
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9
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Chen AYS, Pavitrin A, Ng JCK. Agroinoculation of the cloned infectious cDNAs of Lettuce chlorosis virus results in systemic plant infection and production of whitefly transmissible virions. Virus Res 2012; 169:310-5. [PMID: 22926259 DOI: 10.1016/j.virusres.2012.08.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 08/04/2012] [Accepted: 08/09/2012] [Indexed: 11/26/2022]
Abstract
Lettuce chlorosis virus (LCV) is a single stranded, positive strand RNA virus that is solely transmitted by specific whitefly vectors (Bemisia tabaci biotypes A and B) but not by mechanical leaf-rub inoculation. The roles of viral encoded proteins involved in the infection cycle of LCV have not yet been characterized due to the lack of reverse genetic tools. We present here a report of the successful development of an Agrobacterium-mediated inoculation system for the cloned cDNA constructs of LCV. The cDNAs of both LCV RNAs 1 and 2 were engineered into binary vectors in which the expression of LCV RNAs was regulated under a Cauliflower mosaic virus (CaMV) 35S promoter. In addition, by engineering the sequence elements of the Hepatitis delta virus ribozyme and the nopaline synthase 3' untranslated region immediately downstream of the last nucleotide of LCV RNAs 1 and 2 in the binary vector constructs, the in planta produced LCV transcripts were expected to bear authentic 3' termini. Both constructs were transformed into Agrobacterium tumefaciens cells and infiltrated in Nicotiana benthamiana plants. Three to four weeks post-agroinoculation, the N. benthamiana plants developed typical interveinal chlorosis and LCV infection was detected in the systemic leaves by reverse transcription-PCR. Virions purified from the LCV-infected N. benthamiana plants were flexuous rod-shaped and were transmissible by both B. tabaci biotypes A and B following membrane feeding. These results support the conclusion that Agrobacterium-mediated inoculation of LCV binary vectors in N. benthamiana plants results in LCV infection and the production of biologically active, whitefly transmissible virions. This system represents an important tool for use with reverse genetics designed for the study of LCV gene functions.
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Affiliation(s)
- Angel Y S Chen
- Department of Plant Pathology and Microbiology, University of California, Riverside, CA 92521, United States
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Mongkolsiriwattana C, Chen AYS, Ng JCK. Replication of Lettuce chlorosis virus (LCV), a crinivirus in the family Closteroviridae, is accompanied by the production of LCV RNA 1-derived novel RNAs. Virology 2011; 420:89-97. [PMID: 21945036 DOI: 10.1016/j.virol.2011.08.017] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 07/31/2011] [Accepted: 08/25/2011] [Indexed: 11/18/2022]
Abstract
Cloned infectious complementary DNAs of the bipartite genomic RNAs of Lettuce chlorosis virus (LCV) were constructed. Inoculation of tobacco protoplasts with the in vitro produced RNAs 1 and 2 transcripts, or with RNA 1 transcript alone, resulted in viral replication accompanied by the production of novel LCV RNA 1-derived RNAs. They included the abundantly accumulating LM-LCVR1-1 (~0.38 kb) and LM-LCVR1-2 (~0.3 kb), and the lowly accumulating HM-LCVR1-1 (~8.0 kb) and HM-LCVR1-2 (~6.6 kb), all of which reacted with riboprobes specific to the 5' end of RNA 1 in Northern blot analysis. LM-LCVR1-1 and HM-LCVR1-2 accumulated as positive-stranded RNAs that lacked complementary negative strands, while HM-LCVR1-1 and LM-LCVR1-2 accumulated in both polarities. Additional Northern blot, reverse transcription-polymerase chain reaction, cloning, and sequence analyses revealed LM-LCVR1-2 to be an authentic RNA 1-derived defective (D)RNA, suggesting that its synthesis and maintenance are supported in trans by an RNA 1 encoded replication machinery.
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A virus capsid component mediates virion retention and transmission by its insect vector. Proc Natl Acad Sci U S A 2011; 108:16777-82. [PMID: 21930903 DOI: 10.1073/pnas.1109384108] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Numerous pathogens of humans, animals, and plants are transmitted by specific arthropod vectors. However, understanding the mechanisms governing these pathogen-vector interactions is hampered, in part, by the lack of easy-to-use analytical tools. We investigated whitefly transmission of Lettuce infectious yellows virus (LIYV) by using a unique immunofluorescent localization approach in which we fed virions or recombinant virus capsid components to whiteflies, followed by feeding them antibodies to the virions or capsid components, respectively. Fluorescent signals, indicating the retention of virions, were localized in the anterior foregut or cibarium of a whitefly vector biotype but not within those of a whitefly nonvector biotype. Retention of virions in these locations strongly corresponded with the whitefly vector transmission of LIYV. When four recombinant LIYV capsid components were individually fed to whitefly vectors, significantly more whiteflies retained the recombinant minor coat protein (CPm). As demonstrated previously and in the present study, whitefly vectors failed to transmit virions preincubated with anti-CPm antibodies but transmitted virions preincubated with antibodies recognizing the major coat protein (CP). Correspondingly, the number of insects that specifically retained virions preincubated with anti-CPm antibodies were significantly reduced compared with those that specifically retained virions preincubated with anti-CP antibodies. Notably, a transmission-defective CPm mutant was deficient in specific virion retention, whereas the CPm-restored virus showed WT levels of specific virion retention and transmission. These data provide strong evidence that transmission of LIYV is determined by a CPm-mediated virion retention mechanism in the anterior foregut or cibarium of whitefly vectors.
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Ng JCK, Chen AYS. Acquisition of Lettuce infectious yellows virus by Bemisia tabaci perturbs the transmission of Lettuce chlorosis virus. Virus Res 2011; 156:64-71. [PMID: 21211541 DOI: 10.1016/j.virusres.2010.12.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2010] [Revised: 12/24/2010] [Accepted: 12/24/2010] [Indexed: 11/23/2022]
Abstract
Viruses in the genus Crinivirus infect diverse plant species and are transmitted by specific whitefly vectors, but the basis for vector specific transmission remains poorly understood. Here, we demonstrated that purified virion preparations of Lettuce chlorosis virus (LCV) contained filamentous particles that were consistently transmitted to plants by whiteflies (Bemisia tabaci biotypes A and B) following membrane feeding, suggesting that the preparations contained biologically active virions with all the components essential for specific vector transmission. We also demonstrated in sequential membrane feeding experiments that B. tabaci biotype A pre-fed with high concentrations of Lettuce infectious yellows virus (LIYV) virions followed by decreasing concentrations of LCV virions either abolished or interfered with the transmission of the latter. However, in the reverse treatment, an abolishment/interference in transmission of LIYV was not observed. These results suggest that both viruses share a common transmission pathway in B. tabaci biotype A, and factors other than virion quality and quantity may additionally influence their transmission. To begin investigating the viral determinants that are involved in mediating the whitefly transmission of LCV, virions were analyzed by Western immunoblotting. Our results showed that virions were positively identified by antisera produced against three E. coli expressed recombinant LCV capsid proteins--the major coat protein [CP], minor CP [CPm], and P60.
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Affiliation(s)
- James C K Ng
- Dept. Plant Pathology and Microbiology, University of California, Riverside, CA 92521, United States.
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Stewart LR, Medina V, Tian T, Turina M, Falk BW, Ng JCK. A mutation in the Lettuce infectious yellows virus minor coat protein disrupts whitefly transmission but not in planta systemic movement. J Virol 2010; 84:12165-73. [PMID: 20861267 PMCID: PMC2976407 DOI: 10.1128/jvi.01192-10] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Accepted: 09/09/2010] [Indexed: 11/20/2022] Open
Abstract
The Lettuce infectious yellows virus (LIYV) RNA 2 mutant p1-5b was previously isolated from Bemisia tabaci-transmitted virus maintained in Chenopodium murale plants. p1-5b RNA 2 contains a single-nucleotide deletion in the minor coat protein (CPm) open reading frame (ORF) that is predicted to result in a frameshift and premature termination of the protein. Using the recently developed agroinoculation system for LIYV, we tested RNA 2 containing the p1-5b CPm mutant genotype (agro-pR6-5b) in Nicotiana benthamiana plants. We showed that plant infection triggered by agro-pR6-5b spread systemically and resulted in the formation of virions similar to those produced in p1-5b-inoculated protoplasts. However, virions derived from these mutant CPm genotypes were not transmitted by whiteflies, even though virion concentrations were above the typical transmission thresholds. In contrast, and as demonstrated for the first time, an engineered restoration mutant (agro-pR6-5bM1) was capable of both systemic movement in plants and whitefly transmission. These results provide strong molecular evidence that the full-length LIYV-encoded CPm is dispensable for systemic plant movement but is required for whitefly transmission.
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Affiliation(s)
- Lucy R. Stewart
- Plant Pathology Department, University of California, Davis, One Shields Ave., Davis, California 95616, Department de Producció Vegetal Ciència Forestal, Universitat de Lleida (UdL), Avda. A. Rovira Roure 177, 25198 Lleida, Spain, California Department of Food and Agriculture, Sacramento, California 95832, Instituto di Virologia Vegetale, CNR, Strada delle Cacce 73, 10135 Torino, Italy, Department of Plant Pathology and Microbiology, University of California, Riverside, 900 University Ave., Riverside, California 92521
| | - Vicente Medina
- Plant Pathology Department, University of California, Davis, One Shields Ave., Davis, California 95616, Department de Producció Vegetal Ciència Forestal, Universitat de Lleida (UdL), Avda. A. Rovira Roure 177, 25198 Lleida, Spain, California Department of Food and Agriculture, Sacramento, California 95832, Instituto di Virologia Vegetale, CNR, Strada delle Cacce 73, 10135 Torino, Italy, Department of Plant Pathology and Microbiology, University of California, Riverside, 900 University Ave., Riverside, California 92521
| | - Tongyan Tian
- Plant Pathology Department, University of California, Davis, One Shields Ave., Davis, California 95616, Department de Producció Vegetal Ciència Forestal, Universitat de Lleida (UdL), Avda. A. Rovira Roure 177, 25198 Lleida, Spain, California Department of Food and Agriculture, Sacramento, California 95832, Instituto di Virologia Vegetale, CNR, Strada delle Cacce 73, 10135 Torino, Italy, Department of Plant Pathology and Microbiology, University of California, Riverside, 900 University Ave., Riverside, California 92521
| | - Massimo Turina
- Plant Pathology Department, University of California, Davis, One Shields Ave., Davis, California 95616, Department de Producció Vegetal Ciència Forestal, Universitat de Lleida (UdL), Avda. A. Rovira Roure 177, 25198 Lleida, Spain, California Department of Food and Agriculture, Sacramento, California 95832, Instituto di Virologia Vegetale, CNR, Strada delle Cacce 73, 10135 Torino, Italy, Department of Plant Pathology and Microbiology, University of California, Riverside, 900 University Ave., Riverside, California 92521
| | - Bryce W. Falk
- Plant Pathology Department, University of California, Davis, One Shields Ave., Davis, California 95616, Department de Producció Vegetal Ciència Forestal, Universitat de Lleida (UdL), Avda. A. Rovira Roure 177, 25198 Lleida, Spain, California Department of Food and Agriculture, Sacramento, California 95832, Instituto di Virologia Vegetale, CNR, Strada delle Cacce 73, 10135 Torino, Italy, Department of Plant Pathology and Microbiology, University of California, Riverside, 900 University Ave., Riverside, California 92521
| | - James C. K. Ng
- Plant Pathology Department, University of California, Davis, One Shields Ave., Davis, California 95616, Department de Producció Vegetal Ciència Forestal, Universitat de Lleida (UdL), Avda. A. Rovira Roure 177, 25198 Lleida, Spain, California Department of Food and Agriculture, Sacramento, California 95832, Instituto di Virologia Vegetale, CNR, Strada delle Cacce 73, 10135 Torino, Italy, Department of Plant Pathology and Microbiology, University of California, Riverside, 900 University Ave., Riverside, California 92521
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Wang J, Turina M, Stewart LR, Lindbo JA, Falk BW. Agroinoculation of the Crinivirus, Lettuce infectious yellows virus, for systemic plant infection. Virology 2009; 392:131-6. [PMID: 19632699 DOI: 10.1016/j.virol.2009.06.034] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Revised: 06/09/2009] [Accepted: 06/19/2009] [Indexed: 11/15/2022]
Abstract
Lettuce infectious yellows virus (LIYV) is phloem-limited, non-mechanically transmissible, and is transmitted to plants only by Bemisia tabaci. Here, we developed agroinoculation to deliver LIYV to plants thereby obviating the need for B. tabaci. Agroinfiltration of RNA 1 containing a green fluorescent protein gene into Nicotiana benthamiana leaves resulted in subliminal infections, as judged by green fluorescence. Agroinfiltration of LIYV wild-type RNA 1 and 2 constructs resulted in systemic infections in N. benthamiana plants and typical LIYV symptoms. In addition, partially purified LIYV virions from agroinoculated N. benthamiana plants were successfully acquired via membrane-feeding and transmitted to lettuce plants by B. tabaci. Agroinoculation coupled with targeted mutagenesis technologies will greatly enhance LIYV reverse genetics studies to characterize LIYV gene functions in planta for processes such as virus replication, recombination, trafficking, symptom elicitation and virus-vector interactions.
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Affiliation(s)
- Jinbo Wang
- Department of Plant Pathology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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Wang J, Turina M, Medina V, Falk BW. Synergistic interaction between the Potyvirus, Turnip mosaic virus and the Crinivirus, Lettuce infectious yellows virus in plants and protoplasts. Virus Res 2009; 144:163-70. [PMID: 19409943 DOI: 10.1016/j.virusres.2009.04.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2009] [Revised: 04/10/2009] [Accepted: 04/24/2009] [Indexed: 11/24/2022]
Abstract
Lettuce infectious yellows virus (LIYV), the type member of the genus Crinivirus in the family Closteroviridae, is specifically transmitted by the sweet potato whitefly (Bemisia tabaci) in a semipersistent manner. LIYV infections result in a low virus titer in plants and protoplasts, impeding reverse genetic efforts to analyze LIYV gene/protein functions. We found that synergistic interactions occurred in mixed infections of LIYV and Turnip mosaic virus (TuMV) in Nicotiana benthamiana plants, and these resulted in enhanced accumulation of LIYV. Furthermore, we examined the ability of transgenic plants and protoplasts expressing only the TuMV P1/HC-Pro sequence to enhance the accumulation of LIYV. LIYV RNA and protein titers increased by as much as 8-fold in these plants and protoplasts relative to control plants. LIYV infections remained phloem-limited in P1/HC-Pro transgenic plants, suggesting that enhanced accumulation of LIYV in these plants was due primarily to increased replication efficiency, not to greater spread.
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Affiliation(s)
- Jinbo Wang
- Department of Plant Pathology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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Stewart LR, Hwang MS, Falk BW. Two Crinivirus-specific proteins of Lettuce infectious yellows virus (LIYV), P26 and P9, are self-interacting. Virus Res 2009; 145:293-9. [PMID: 19665507 DOI: 10.1016/j.virusres.2009.07.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2009] [Revised: 07/07/2009] [Accepted: 07/28/2009] [Indexed: 11/24/2022]
Abstract
Interactions of Lettuce infectious yellows virus (LIYV)-encoded proteins were tested by yeast-two-hybrid (Y2H) assays. LIYV-encoded P34, Hsp70h, P59, CP, CPm, and P26 were tested in all possible pairwise combinations. Interaction was detected only for the P26-P26 combination. P26 self-interaction domains were mapped using a series of N- and C-terminal truncations. Orthologous P26 proteins from the criniviruses Beet pseudoyellows virus (BPYV), Cucurbit yellow stunting disorder virus (CYSDV), and Lettuce chlorosis virus (LCV) were also tested, and each exhibited strong self-interaction but no interaction with orthologous proteins. Two small putative proteins encoded by LIYV RNA2, P5 and P9, were also tested for interactions with the six aforementioned LIYV proteins and each other. No interactions were detected for P5, but P9-P9 self-interaction was detected. P26- and P9-encoding genes are present in all described members of the genus Crinivirus, but are not present in other members of the family Closteroviridae. LIYV P26 has previously been demonstrated to induce a unique LIYV cytopathology, plasmalemma deposits (PLDs), but no role is yet known for P9.
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Affiliation(s)
- Lucy R Stewart
- Department of Plant Pathology, University of California, Davis, One Shields Ave., Davis, CA 95616, USA.
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Stewart LR, Medina V, Sudarshana MR, Falk BW. Lettuce infectious yellows virus-encoded P26 induces plasmalemma deposit cytopathology. Virology 2009; 388:212-20. [PMID: 19375143 DOI: 10.1016/j.virol.2009.03.016] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2009] [Revised: 02/28/2009] [Accepted: 03/17/2009] [Indexed: 11/19/2022]
Abstract
Lettuce infectious yellows virus (LIYV) encodes a 26 kDa protein (P26) previously shown to associate with plasmalemma deposits (PLDs), unique LIYV-induced cytopathologies located at the plasmalemma over plasmodesmata pit fields in companion cells and phloem parenchyma. To further characterize the relationship of P26 and PLDs, we assessed localization and cytopathology induction of P26 expressed from either LIYV or a heterologous Tobacco mosaic virus (TMV) vector using green fluorescent protein (GFP) fusions, immunofluorescence microscopy, biochemical fractionation, and transmission electron microscopy (TEM). TEM analyses demonstrated that P26 not only associated with, but induced formation of PLDs in the absence of other LIYV proteins. Interestingly, PLDs induced by P26-expressing TMV were no longer confined to phloem cells. Putative P26 orthologs from two other members of the genus Crinivirus which do not induce conspicuous PLDs exhibited fractionation properties similar to LIYV P26 but were not associated with any PLD-like cytopathology.
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Affiliation(s)
- Lucy R Stewart
- Department of Plant Pathology, University of California, Davis, CA 95616, USA
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18
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Wang J, Yeh HH, Falk BW. cis preferential replication of Lettuce infectious yellows virus (LIYV) RNA 1: the initial step in the asynchronous replication of the LIYV genomic RNAs. Virology 2009; 386:217-23. [PMID: 19181359 DOI: 10.1016/j.virol.2009.01.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2008] [Revised: 12/30/2008] [Accepted: 01/06/2009] [Indexed: 10/21/2022]
Abstract
A series of Lettuce infectious yellows virus (LIYV) RNA 1 mutants was created to evaluate their ability to replicate in tobacco protoplasts. Mutants DeltaEcoRI, DeltaE-LINK, and Delta1B, having deletions in open reading frames (ORFs) 1A and 1B, did not replicate when individually inoculated to protoplasts or when co-inoculated with wild-type RNA1 as a helper virus. A fragment of the green fluorescent protein (GFP) gene was inserted into the RNA 1 ORF 2 (P34) in order to provide a unique sequence tag. This mutant, P34-GFP TAG, was capable of independent replication in protoplasts. Mutants derived from P34-GFP TAG having frameshift mutations in the ORF 1A or 1B were unable to replicate in protoplasts alone or in trans when co-inoculated with wild-type RNA1 as a helper virus. Taken together, these data strongly suggest that LIYV RNA 1 replication is cis-preferential.
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Affiliation(s)
- Jinbo Wang
- Department of Plant Pathology, University of California, Davis, One Shields Avenue, Davis, CA 95616, USA
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