1
|
Córdoba L, Ruiz-Padilla A, Rodríguez-Romero J, Ayllón MA. Construction and Characterization of a Botrytis Virus F Infectious Clone. J Fungi (Basel) 2022; 8:jof8050459. [PMID: 35628716 PMCID: PMC9146958 DOI: 10.3390/jof8050459] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 04/15/2022] [Accepted: 04/26/2022] [Indexed: 11/30/2022] Open
Abstract
Botrytis virus F (BVF) is a positive-sense, single-stranded RNA (+ssRNA) virus within the Gammaflexiviridae family of the plant-pathogenic fungus Botrytis cinerea. In this study, the complete sequence of a BVF strain isolated from B. cinerea collected from grapevine fields in Spain was analyzed. This virus, in this work BVF-V448, has a genome of 6827 nt in length, excluding the poly(A) tail, with two open reading frames encoding an RNA dependent RNA polymerase (RdRP) and a coat protein (CP). The 5′- and 3′-terminal regions of the genome were determined by rapid amplification of cDNA ends (RACE). Furthermore, a yet undetected subgenomic RNA species in BVF-V448 was identified, indicating that the CP is expressed via 3′ coterminal subgenomic RNAs (sgRNAs). We also report the successful construction of the first BVF full-length cDNA clone and synthesized in vitro RNA transcripts using the T7 polymerase, which could efficiently transfect two different strains of B. cinerea, B05.10 and Pi258.9. The levels of growth in culture and virulence on plants of BVF-V448 transfected strains were comparable to BVF-free strains. The infectious clones generated in this work provide a useful tool for the future development of an efficient BVF foreign gene expression vector and a virus-induced gene silencing (VIGS) vector as a biological agent for the control of B. cinerea.
Collapse
Affiliation(s)
- Laura Córdoba
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain; (L.C.); (A.R.-P.); (J.R.-R.)
| | - Ana Ruiz-Padilla
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain; (L.C.); (A.R.-P.); (J.R.-R.)
| | - Julio Rodríguez-Romero
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain; (L.C.); (A.R.-P.); (J.R.-R.)
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
| | - María A. Ayllón
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, Pozuelo de Alarcón, 28223 Madrid, Spain; (L.C.); (A.R.-P.); (J.R.-R.)
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid (UPM), 28040 Madrid, Spain
- Correspondence:
| |
Collapse
|
2
|
Niu E, Liu H, Zhou H, Luo L, Wu Y, Andika IB, Sun L. Autophagy Inhibits Intercellular Transport of Citrus Leaf Blotch Virus by Targeting Viral Movement Protein. Viruses 2021; 13:2189. [PMID: 34834995 PMCID: PMC8619118 DOI: 10.3390/v13112189] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Revised: 10/26/2021] [Accepted: 10/26/2021] [Indexed: 12/12/2022] Open
Abstract
Autophagy is an evolutionarily conserved cellular-degradation mechanism implicated in antiviral defense in plants. Studies have shown that autophagy suppresses virus accumulation in cells; however, it has not been reported to specifically inhibit viral spread in plants. This study demonstrated that infection with citrus leaf blotch virus (CLBV; genus Citrivirus, family Betaflexiviridae) activated autophagy in Nicotiana benthamiana plants as indicated by the increase of autophagosome formation. Impairment of autophagy through silencing of N. benthamiana autophagy-related gene 5 (NbATG5) and NbATG7 enhanced cell-to-cell and systemic movement of CLBV; however, it did not affect CLBV accumulation when the systemic infection had been fully established. Treatment using an autophagy inhibitor or silencing of NbATG5 and NbATG7 revealed that transiently expressed movement protein (MP), but not coat protein, of CLBV was targeted by selective autophagy for degradation. Moreover, we identified that CLBV MP directly interacted with NbATG8C1 and NbATG8i, the isoforms of autophagy-related protein 8 (ATG8), which are key factors that usually bind cargo receptors for selective autophagy. Our results present a novel example in which autophagy specifically targets a viral MP to limit the intercellular spread of the virus in plants.
Collapse
Affiliation(s)
- Erbo Niu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (E.N.); (H.Z.); (L.L.)
| | - Huan Liu
- School of Modern Agriculture and Biotechnology, Ankang University, Ankang 725000, China;
| | - Hongsheng Zhou
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (E.N.); (H.Z.); (L.L.)
| | - Lian Luo
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (E.N.); (H.Z.); (L.L.)
| | - Yunfeng Wu
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (E.N.); (H.Z.); (L.L.)
| | - Ida Bagus Andika
- College of Plant Health and Medicine, Qingdao Agricultural University, Qingdao 266109, China
| | - Liying Sun
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Plant Protection, Northwest A&F University, Xianyang 712100, China; (E.N.); (H.Z.); (L.L.)
| |
Collapse
|
3
|
Gómez‐Muñoz N, Velázquez K, Vives MC, Ruiz‐Ruiz S, Pina JA, Flores R, Moreno P, Guerri J. The resistance of sour orange to Citrus tristeza virus is mediated by both the salicylic acid and RNA silencing defence pathways. MOLECULAR PLANT PATHOLOGY 2017; 18:1253-1266. [PMID: 27588892 PMCID: PMC6638288 DOI: 10.1111/mpp.12488] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 08/26/2016] [Accepted: 08/30/2016] [Indexed: 05/08/2023]
Abstract
Citrus tristeza virus (CTV) induces in the field the decline and death of citrus varieties grafted on sour orange (SO) rootstock, which has forced the use of alternative decline-tolerant rootstocks in affected countries, despite the highly desirable agronomic features of the SO rootstock. Declining citrus plants display phloem necrosis below the bud union. In addition, SO is minimally susceptible to CTV compared with other citrus varieties, suggesting partial resistance of SO to CTV. Here, by silencing different citrus genes with a Citrus leaf blotch virus-based vector, we have examined the implication of the RNA silencing and salicylic acid (SA) defence pathways in the resistance of SO to CTV. Silencing of the genes RDR1, NPR1 and DCL2/DCL4, associated with these defence pathways, enhanced virus spread and accumulation in SO plants in comparison with non-silenced controls, whereas silencing of the genes NPR3/NPR4, associated with the hypersensitive response, produced a slight decrease in CTV accumulation and reduced stunting of SO grafted on CTV-infected rough lemon plants. We also found that the CTV RNA silencing suppressors p20 and p23 also suppress the SA signalling defence, with the suppressor activity being higher in the most virulent isolates.
Collapse
Affiliation(s)
- Neus Gómez‐Muñoz
- Instituto Valenciano de Investigaciones Agrarias (IVIA)Centro de Protección Vegetal y BiotecnologíaMoncada, Valencia46113Spain
| | - Karelia Velázquez
- Instituto Valenciano de Investigaciones Agrarias (IVIA)Centro de Protección Vegetal y BiotecnologíaMoncada, Valencia46113Spain
| | - María Carmen Vives
- Instituto Valenciano de Investigaciones Agrarias (IVIA)Centro de Protección Vegetal y BiotecnologíaMoncada, Valencia46113Spain
| | - Susana Ruiz‐Ruiz
- Instituto Valenciano de Investigaciones Agrarias (IVIA)Centro de Protección Vegetal y BiotecnologíaMoncada, Valencia46113Spain
| | - José Antonio Pina
- Instituto Valenciano de Investigaciones Agrarias (IVIA)Centro de Protección Vegetal y BiotecnologíaMoncada, Valencia46113Spain
| | - Ricardo Flores
- Instituto de Biología Molecular y Celular de Plantas (UPV‐CSIC), Universidad Politécnica de Valencia, Avenida de los NaranjosValencia46022Spain
| | - Pedro Moreno
- Instituto Valenciano de Investigaciones Agrarias (IVIA)Centro de Protección Vegetal y BiotecnologíaMoncada, Valencia46113Spain
| | - José Guerri
- Instituto Valenciano de Investigaciones Agrarias (IVIA)Centro de Protección Vegetal y BiotecnologíaMoncada, Valencia46113Spain
| |
Collapse
|
4
|
Velázquez K, Agüero J, Vives MC, Aleza P, Pina JA, Moreno P, Navarro L, Guerri J. Precocious flowering of juvenile citrus induced by a viral vector based on Citrus leaf blotch virus: a new tool for genetics and breeding. PLANT BIOTECHNOLOGY JOURNAL 2016; 14:1976-85. [PMID: 26920394 PMCID: PMC5043495 DOI: 10.1111/pbi.12555] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Revised: 02/04/2016] [Accepted: 02/19/2016] [Indexed: 05/17/2023]
Abstract
The long juvenile period of citrus trees (often more than 6 years) has hindered genetic improvement by traditional breeding methods and genetic studies. In this work, we have developed a biotechnology tool to promote transition from the vegetative to the reproductive phase in juvenile citrus plants by expression of the Arabidopsis thaliana or citrus FLOWERING LOCUS T (FT) genes using a Citrus leaf blotch virus-based vector (clbvINpr-AtFT and clbvINpr-CiFT, respectively). Citrus plants of different genotypes graft inoculated with either of these vectors started flowering within 4-6 months, with no alteration of the plant architecture, leaf, flower or fruit morphology in comparison with noninoculated adult plants. The vector did not integrate in or recombine with the plant genome nor was it pollen or vector transmissible, albeit seed transmission at low rate was detected. The clbvINpr-AtFT is very stable, and flowering was observed over a period of at least 5 years. Precocious flowering of juvenile citrus plants after vector infection provides a helpful and safe tool to dramatically speed up genetic studies and breeding programmes.
Collapse
Affiliation(s)
- Karelia Velázquez
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Valencia, Spain
| | - Jesús Agüero
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Valencia, Spain
| | - María C Vives
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Valencia, Spain
| | - Pablo Aleza
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Valencia, Spain
| | - José A Pina
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Valencia, Spain
| | - Pedro Moreno
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Valencia, Spain
| | - Luis Navarro
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Valencia, Spain
| | - José Guerri
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Moncada, Valencia, Spain.
| |
Collapse
|
5
|
Blanco-Pérez M, Hernández C. Evidence supporting a premature termination mechanism for subgenomic RNA transcription in Pelargonium line pattern virus: identification of a critical long-range RNA-RNA interaction and functional variants through mutagenesis. J Gen Virol 2016; 97:1469-1480. [PMID: 26990209 DOI: 10.1099/jgv.0.000459] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pelargonium line pattern virus (PLPV) is a plus-strand RNA virus that has been proposed as type species of a tentative new genus, Pelarspovirus, in the family Tombusviridae. One of the singular traits of members of this prospective genus is the production of a unique subgenomic (sg) mRNA that is structurally and functionally tricistronic. Here, we have aimed to get insights into the mechanism that governs PLPV sg mRNA transcription. A long-range RNA-RNA interaction that is critical for the process has been identified through RNA folding predictions and mutational analysis of the viral genome. Such interaction seems to occur in the plus-strand, likely acts in cis, and specifically mediates the synthesis of sg RNA-sized minus-strand. The accumulation of this RNA species is easily detectable in plants and its generation can be uncoupled from that of the plus-strand sg mRNA. All these data together with the observation that 5' ends of PLPV genomic and sg mRNAs have sequence resemblances (as expected if both act as promoters in the corresponding minus-strand), support that premature termination is the mechanism underlying PLPV sg mRNA formation.
Collapse
Affiliation(s)
- Marta Blanco-Pérez
- Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia), Ciudad Politécnica e la Innovación, Ed. 8E. Camino de Vera s/n, 46022, Valencia, Spain
| | - Carmen Hernández
- Instituto de Biología Molecular y Celular de Plantas (Consejo Superior de Investigaciones Científicas-Universidad Politécnica de Valencia), Ciudad Politécnica e la Innovación, Ed. 8E. Camino de Vera s/n, 46022, Valencia, Spain
| |
Collapse
|
6
|
Agüero J, Vives MDC, Velázquez K, Pina JA, Navarro L, Moreno P, Guerri J. Effectiveness of gene silencing induced by viral vectors based on Citrus leaf blotch virus is different in Nicotiana benthamiana and citrus plants. Virology 2014; 460-461:154-64. [PMID: 25010281 DOI: 10.1016/j.virol.2014.04.017] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 02/12/2014] [Accepted: 04/12/2014] [Indexed: 11/23/2022]
Abstract
Virus induced gene silencing (VIGS) is an effective technology for gene function analysis in plants. We assessed the VIGS effectiveness in Nicotiana benthamiana and citrus plants of different Citrus leaf blotch virus (CLBV)-based vectors, using insets of the phytoene desaturase (pds) gene. While in N. benthamiana the silencing phenotype was induced only by the construct carrying a 58-nt pds hairpin, in citrus plants all the constructs induced the silencing phenotype. Differences in the generation of secondary small interfering RNAs in both species are believed to be responsible for differential host-species effects. The ability of CLBV-based vectors to silence different endogenous citrus genes was further confirmed. Since CLBV-based vectors are known to be stable and induce VIGS in successive flushes for several months, these vectors provide an important genomic tool and it is expected that they will be useful to analyze gene function by reverse genetics in the long-lived citrus plants.
Collapse
Affiliation(s)
- Jesus Agüero
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera Km. 4.5, Moncada, 46113 Valencia, Spain
| | - María del Carmen Vives
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera Km. 4.5, Moncada, 46113 Valencia, Spain
| | - Karelia Velázquez
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera Km. 4.5, Moncada, 46113 Valencia, Spain
| | - José Antonio Pina
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera Km. 4.5, Moncada, 46113 Valencia, Spain
| | - Luis Navarro
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera Km. 4.5, Moncada, 46113 Valencia, Spain
| | - Pedro Moreno
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera Km. 4.5, Moncada, 46113 Valencia, Spain
| | - Jose Guerri
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias (IVIA), Ctra. Moncada-Náquera Km. 4.5, Moncada, 46113 Valencia, Spain.
| |
Collapse
|
7
|
Agüero J, Vives MC, Velázquez K, Ruiz-Ruiz S, Juárez J, Navarro L, Moreno P, Guerri J. Citrus leaf blotch virus invades meristematic regions in Nicotiana benthamiana and citrus. MOLECULAR PLANT PATHOLOGY 2013; 14:610-6. [PMID: 23560714 PMCID: PMC6638833 DOI: 10.1111/mpp.12031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
To invade systemically host plants, viruses need to replicate in the infected cells, spread to neighbouring cells through plasmodesmata and move to distal parts of the plant via sieve tubes to start new infection foci. To monitor the infection of Nicotiana benthamiana plants by Citrus leaf blotch virus (CLBV), leaves were agroinoculated with an infectious cDNA clone of the CLBV genomic RNA expressing green fluorescent protein (GFP) under the transcriptional control of a duplicate promoter of the coat protein subgenomic RNA. Fluorescent spots first appeared in agroinfiltrated leaves 11-12 days after infiltration, indicating CLBV replication. Then, after entering the phloem vascular system, CLBV was unloaded in the upper parts of the plant and invaded all tissues, including flower organs and meristems. GFP fluorescence was not visible in citrus plants infected with CLBV-GFP. Therefore, to detect CLBV in meristematic regions, Mexican lime (Citrus aurantifolia) plants were graft inoculated with CLBV, with Citrus tristeza virus (CTV), a virus readily eliminated by shoot-tip grafting in vitro, or with both simultaneously. Although CLBV was detected by hybridization and real-time reverse transcription-polymerase chain reaction (RT-PCR) in 0.2-mm shoot tips in all CLBV-inoculated plants, CTV was not detected. These results explain the difficulty in eliminating CLBV by shoot-tip grafting in vitro.
Collapse
Affiliation(s)
- Jesús Agüero
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias-IVIA, Moncada, Valencia 46113, Spain
| | | | | | | | | | | | | | | |
Collapse
|
8
|
Agüero J, Ruiz-Ruiz S, Del Carmen Vives M, Velázquez K, Navarro L, Peña L, Moreno P, Guerri J. Development of viral vectors based on Citrus leaf blotch virus to express foreign proteins or analyze gene function in citrus plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:1326-37. [PMID: 22670755 DOI: 10.1094/mpmi-02-12-0048-r] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Viral vectors have been used to express foreign proteins in plants or to silence endogenous genes. This methodology could be appropriate for citrus plants that have long juvenile periods and adult plants that are difficult to transform. We developed viral vectors based on Citrus leaf blotch virus (CLBV) by duplicating a minimum promoter (92 bp) either at the 3' untranslated region (clbv3'pr vector) or at the intergenic region between the movement and coat protein (CP) genes (clbvINpr vector). The duplicated fragment (-42/+50) around the transcription start site of the CP subgenomic RNA (sgRNA) had the full promoter activity and induced synthesis of a new sgRNA in infected plants. Agroinoculation with these vectors resulted in systemic infection of Nicotiana benthamiana and the resulting virions systemically infected citrus plants. A clbvINpr vector carrying the green fluorescent protein (GFP) gene expressed GFP in citrus plants and triggered gfp silencing in gfp-transgenic citrus plants, and vectors carrying fragments of the phytoene desaturase or the magnesium chelatase genes incited a silencing phenotype in citrus plants. These silenced phenotypes persisted in successive flushes. Because CLBV infections are symptomless in most citrus species, the effective silencing induced by CLBV-derived vectors will be helpful to analyze citrus gene function.
Collapse
Affiliation(s)
- Jesús Agüero
- Instituto Valenciano de Investigaciones Agrarias, Valencia, Spain
| | | | | | | | | | | | | | | |
Collapse
|
9
|
Komatsu K, Hirata H, Fukagawa T, Yamaji Y, Okano Y, Ishikawa K, Adachi T, Maejima K, Hashimoto M, Namba S. Infection of capilloviruses requires subgenomic RNAs whose transcription is controlled by promoter-like sequences conserved among flexiviruses. Virus Res 2012; 167:8-15. [DOI: 10.1016/j.virusres.2012.02.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2011] [Revised: 02/18/2012] [Accepted: 02/20/2012] [Indexed: 11/16/2022]
|
10
|
Renovell Á, Vives MC, Ruiz-Ruiz S, Navarro L, Moreno P, Guerri J. The Citrus leaf blotch virus movement protein acts as silencing suppressor. Virus Genes 2012; 44:131-40. [PMID: 21948005 DOI: 10.1007/s11262-011-0674-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2011] [Accepted: 09/12/2011] [Indexed: 01/25/2023]
Abstract
To counteract plant antiviral defense based on RNA silencing, many viruses express proteins that inhibit this mechanism at different levels. The genome of Citrus leaf blotch virus (CLBV) encodes a 227-kDa protein involved in replication, a 40-kDa movement protein (MP), and a 41-kDa coat protein (CP). To determine if any of these proteins might have RNA silencing suppressor activities, we have used Agrobacterium-mediated transient assays in the green fluorescent protein (GFP)-expressing Nicotiana benthamiana line 16c. Only CLBV MP was able to suppress intracellular GFP silencing induced by expression of either single- or double-stranded (ds) GFP RNA, but not cell-to-cell or long distance spread of the silencing signal. The MP suppressor activity was weak compared to other characterized viral suppressor proteins. Overall our data indicate that MP acts as a suppressor of local silencing probably by interfering in the silencing pathway downstream of the steps of dsRNA and small RNAs generation.
Collapse
Affiliation(s)
- Águeda Renovell
- Centro de Protección Vegetal y Biotecnología, Instituto Valenciano de Investigaciones Agrarias, Ctra. Moncada-Náquera Km. 4.5, 46113 Moncada, Valencia, Spain
| | | | | | | | | | | |
Collapse
|