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Li CX, Zhu JZ, Gao BD, Zhu HJ, Zhou Q, Zhong J. Characterization of a Novel Ourmia-Like Mycovirus Infecting Magnaporthe oryzae and Implications for Viral Diversity and Evolution. Viruses 2019; 11:v11030223. [PMID: 30841545 PMCID: PMC6465991 DOI: 10.3390/v11030223] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 02/26/2019] [Accepted: 03/01/2019] [Indexed: 01/06/2023] Open
Abstract
Here, the molecular characterization of a novel mycovirus that was isolated from a phytopathogenic fungus Magnaporthe oryzae and designed as Magnaporthe oryzae ourmia-like virus 4 (MOLV4) is reported. MOLV4 has a genome that is 2497 bp long and possesses a single open reading frame (ORF), which encodes the product RNA-dependent RNA polymerase (RdRp). Sequence similarities were found between the MOLV4 encoded RdRp and the counterparts of a few previously reported ourmia-like mycoviruses. Virus-curing and biological comparison indicate that the virus has no or mild effects on the morphology and mycelium growth rate of the host fungus. Phylogenetic analysis using the RdRp aa sequences was performed. The results show that MOLV4 is clustered with the ourmia-like mycoviruses, forming a clade closely related to ourmiaviruses but distinct from narnaviruses. In addition, database searches revealed that several MOLV4-related sequences are present in the transcriptome shotgun assembly (TSA) library, expressed sequence tag database (ESTdb), whole-genome shotgun (WGS) library, and genomic survey sequences (GSS) libraries of a few other species of eukaryote organisms. Our results show that MOLV4, together with other similar ourmia-like mycoviruses, might represent a virus clade that links the plant ourmiaviruses and fungal narnaviruses and has a wide range of hosts.
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Affiliation(s)
- Chang Xin Li
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
| | - Jun Zi Zhu
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
| | - Bi Da Gao
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
| | - Hong Jian Zhu
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
| | - Qian Zhou
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
| | - Jie Zhong
- Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Nongda Road 1, Furong District, Changsha 410128, China.
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Ferriol INMACULADA, Vallino MARTA, Ciuffo MARINA, Nigg JAREDC, Zamora‐Macorra ERIKAJ, Falk BRYCEW, Turina M. The Torradovirus-specific RNA2-ORF1 protein is necessary for plant systemic infection. MOLECULAR PLANT PATHOLOGY 2018; 19:1319-1331. [PMID: 28940803 PMCID: PMC6638011 DOI: 10.1111/mpp.12615] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 09/13/2017] [Accepted: 09/18/2017] [Indexed: 06/07/2023]
Abstract
Tomato apex necrosis virus (ToANV, species Tomato marchitez virus, genus Torradovirus, family Secoviridae) causes a severe tomato disease in Mexico. One distinctive feature of torradoviruses compared with other members of the family Secoviridae is the presence of an additional open reading frame (ORF) in genomic RNA2 (denominated RNA2-ORF1), located upstream of ORF2. RNA2-ORF2 encodes a polyprotein that is processed into a putative movement protein and three capsid proteins (CPs). The RNA2-ORF1 protein has homologues only amongst other torradoviruses and, so far, no function has been associated with it. We used recombinant and mutant ToANV clones to investigate the role of the RNA2-ORF1 protein in various aspects of the virus infection cycle. The lack of a functional RNA2-ORF1 resulted in an inability to systemically infect Nicotiana benthamiana and tomato plants, but both positive- and negative-strand RNA1 and RNA2 accumulated locally in agroinfiltrated areas in N. benthamiana plants, indicating that the RNA2-ORF1 mutants were replication competent. Furthermore, a mutant with a deletion in RNA2-ORF1 was competent for virion formation and cell-to-cell movement in the cells immediately surrounding the initial infection site. However, immunological detection of the ToANV CPs in the agroinfiltrated areas showed that this mutant was not detected in the sieve elements even if the surrounding parenchymatic cells were ToANV positive, suggesting a role for the RNA2-ORF1 protein in processes occurring prior to phloem uploading, including efficient spread in inoculated leaves.
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Affiliation(s)
| | - MARTA Vallino
- Institute for Sustainable Plant Protection, CNRTurin10135Italy
| | - MARINA Ciuffo
- Institute for Sustainable Plant Protection, CNRTurin10135Italy
| | - JARED C. Nigg
- Department of Plant PathologyUC‐DavisDavisCA 95616USA
| | | | - BRYCE W. Falk
- Department of Plant PathologyUC‐DavisDavisCA 95616USA
| | - Massimo Turina
- Institute for Sustainable Plant Protection, CNRTurin10135Italy
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Alam SB, Reade R, Theilmann J, Rochon D. Evidence for the role of basic amino acids in the coat protein arm region of Cucumber necrosis virus in particle assembly and selective encapsidation of viral RNA. Virology 2017; 512:83-94. [PMID: 28946005 DOI: 10.1016/j.virol.2017.09.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 08/31/2017] [Accepted: 09/02/2017] [Indexed: 01/21/2023]
Abstract
Cucumber necrosis virus (CNV) is a T = 3 icosahedral virus with a (+)ssRNA genome. The N-terminal CNV coat protein arm contains a conserved, highly basic sequence ("KGRKPR"), which we postulate is involved in RNA encapsidation during virion assembly. Seven mutants were constructed by altering the CNV "KGRKPR" sequence; the four basic residues were mutated to alanine individually, in pairs, or in total. Virion accumulation and vRNA encapsidation were significantly reduced in mutants containing two or four substitutions and virion morphology was also affected, where both T = 1 and intermediate-sized particles were produced. Mutants with two or four substitutions encapsidated significantly greater levels of truncated RNA than that of WT, suggesting that basic residues in the "KGRKPR" sequence are important for encapsidation of full-length CNV RNA. Interestingly, "KGRKPR" mutants also encapsidated relatively higher levels of host RNA, suggesting that the "KGRKPR" sequence also contributes to selective encapsidation of CNV RNA.
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Affiliation(s)
- Syed Benazir Alam
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, B.C., Canada
| | - Ron Reade
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, B.C., Canada
| | - Jane Theilmann
- Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, B.C., Canada
| | - D'Ann Rochon
- Faculty of Land and Food Systems, University of British Columbia, Vancouver, B.C., Canada; Summerland Research and Development Centre, Agriculture and Agri-Food Canada, Summerland, B.C., Canada.
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Nerva L, Silvestri A, Ciuffo M, Palmano S, Varese GC, Turina M. Transmission of Penicillium aurantiogriseum partiti-like virus 1 to a new fungal host (Cryphonectria parasitica) confers higher resistance to salinity and reveals adaptive genomic changes. Environ Microbiol 2017; 19:4480-4492. [PMID: 28836717 DOI: 10.1111/1462-2920.13894] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 08/12/2017] [Indexed: 11/27/2022]
Abstract
We attempted to transfect six recently characterized virus species to protoplasts of Penicillium janczewskii and Chryphonectria parasitica. None of the recovered P. janczewskii colonies was positive for the transfected viruses, but Penicillium aurantiogriseum partiti-like virus 1 (PaPLV1) was detected in three distinct regenerated C. parasitica colonies. We screened the phenotype of the infected strains in up to 45 different conditions combining different media, salinity and temperatures: our results show that the infected strains grow slower than the virus- free in most of the tested conditions with the exception of halophilic stress in a specific nutrient combination media. We proceeded to characterize molecularly the population of distinct isolates of PaPLV1 infected C. parasitica through RNAseq: comparison to the viral population present in the original host - P. auratiogriseum - showed that two isolates accumulated non-synonymous mutations suggesting adaptation to the new host. RNAseq analyses identified a second genomic RNA segment and northern blot of RNA extracted from purified virus suspensions allowed establishing that PaPLV1 is at least bipartite in nature and that it forms isometric virions of circa 36-38 nm in diameter. In light of these new acquisitions, we discuss the taxonomic placement of PaPLV1 inside the Partitiviridae.
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Affiliation(s)
- Luca Nerva
- Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, Torino 10135, Italy.,Department of Life Sciences and Systems Biology, University of Turin, Mycotheca Universitatis Taurinensis (MUT), Viale Mattioli 25, Torino 10125, Italy
| | - Alessandro Silvestri
- Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, Torino 10135, Italy.,Department of Life Sciences and Systems Biology, University of Turin, Mycotheca Universitatis Taurinensis (MUT), Viale Mattioli 25, Torino 10125, Italy
| | - Marina Ciuffo
- Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, Torino 10135, Italy
| | - Sabrina Palmano
- Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, Torino 10135, Italy
| | - Givanna Cristina Varese
- Department of Life Sciences and Systems Biology, University of Turin, Mycotheca Universitatis Taurinensis (MUT), Viale Mattioli 25, Torino 10125, Italy
| | - Massimo Turina
- Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, Torino 10135, Italy
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Turina M, Hillman BI, Izadpanah K, Rastgou M, Rosa C, Ictv Report Consortium. ICTV Virus Taxonomy Profile: Ourmiavirus. J Gen Virol 2017; 98:129-130. [PMID: 28284246 PMCID: PMC5802297 DOI: 10.1099/jgv.0.000725] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Members of the plant virus genus Ourmiavirus are characterized by having non-enveloped bacilliform virions with a series of discrete lengths from 30 to 62 nm composed of a single coat protein (CP). The genome consists of three positive-sense single-stranded RNAs, each encoding a single protein. The RNA-dependent RNA polymerase (RdRp) has closest similarity to that of viruses from the family Narnaviridae; the movement protein (MP) is similar to the MPs of tombusviruses; the CP shows limited similarity to the CPs of several plant and animal viruses. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the taxonomy of the genus Ourmiavirus, which is available at www.ictv.global/report/ourmiavirus.
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Affiliation(s)
- Massimo Turina
- Institute for Sustainable Plant Protection-CNR, Strada delle Cacce 73, Torino 10135, Italy
| | - Brad I Hillman
- Department of Plant Biology and Pathology, Rutgers University, New Brunswick, NJ 08901, USA
| | - Keramat Izadpanah
- Plant Virology Research Center, College of Agriculture, Shiraz University, Shiraz 71441 65186, Iran
| | - Mina Rastgou
- Department of Plant Protection, College of Agriculture, Urmia University, Urmia 57561 51818, Iran
| | - Cristina Rosa
- Department of Plant Pathology and Environmental Microbiology, College of Agricultural Sciences, The Pennsylvania State University, University Park, PA 16802, USA
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Bertran A, Ciuffo M, Margaria P, Rosa C, Oliveira Resende R, Turina M. Host-specific accumulation and temperature effects on the generation of dimeric viral RNA species derived from the S-RNA of members of the Tospovirus genus. J Gen Virol 2016; 97:3051-3062. [PMID: 27600541 DOI: 10.1099/jgv.0.000598] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Polygonum ringspot virus (PolRSV) is a recently characterized Tospovirus reported in Italy. Northern blot analyses of PolRSV infections in Nicotiana benthamiana and tomato plants showed that a viral RNA species with nearly twice the length of the Small genomic RNA (S-RNA) accumulated abundantly in the former host, but was not detected in the latter. Additional assays confirmed that biogenesis of this novel RNA species was common to all PolRSV isolates tested and also to an isolate of Tomato spotted wilt virus (TSWV). Given its size, we hypothesized that the novel RNA species was a dimer molecule and we confirmed this hypothesis by RNA sequencing (RNAseq) analysis and reverse transcription (RT)-PCR of putative predicted dimer junction sites in RNA extracts of N. benthamiana challenged with PolRSV isolates Plg6 and Plg13/2. We also confirmed that these molecules are derived from head-to-tail dimers and often contain deletions at their junction sites. We named these novel molecules imperfect dimer RNAs (IMPD-RNAs). PolRSV IMPD-RNAs systemic accumulation in a range of host plants was restricted to N. benthamiana and Nicotiana occidentalis. Notably, IMPD-RNAs accumulation was modulated by temperature and their generation was restricted to late stages of systemic infection (12 days post-inoculation) in N. benthamiana. Differently from all other PolRSV isolates used in this study, Plg13/2 generated more IMPD-RNAs coupled with low amounts of genomic S-RNA and maintained them even at 18 °C, besides having lost the ability to infect tomato plants. This is the first characterization of S-RNA dimers for Tospovirus, and of occurrence of dimers of genomic segments at the whole organism level for Bunyaviridae.
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Affiliation(s)
- André Bertran
- Institute for Sustainable Plant Protection, CNR, Turin, Piemonte, Italy
- Plant Virology Laboratory, Institute of Biological Sciences, University of Brasília, Brazil
| | - Marina Ciuffo
- Institute for Sustainable Plant Protection, CNR, Turin, Piemonte, Italy
| | - Paolo Margaria
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, USA
| | - Cristina Rosa
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, USA
| | - Renato Oliveira Resende
- Institute for Sustainable Plant Protection, CNR, Turin, Piemonte, Italy
- Plant Virology Laboratory, Institute of Biological Sciences, University of Brasília, Brazil
| | - Massimo Turina
- Institute for Sustainable Plant Protection, CNR, Turin, Piemonte, Italy
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Margaria P, Anderson CT, Turina M, Rosa C. Identification of Ourmiavirus 30K movement protein amino acid residues involved in symptomatology, viral movement, subcellular localization and tubule formation. MOLECULAR PLANT PATHOLOGY 2016; 17:1063-79. [PMID: 26637973 PMCID: PMC6638536 DOI: 10.1111/mpp.12348] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 11/26/2015] [Indexed: 05/03/2023]
Abstract
Several plant viruses encode movement proteins (MPs) classified in the 30K superfamily. Despite a great functional diversity, alignment analysis of MP sequences belonging to the 30K superfamily revealed the presence of a central core region, including amino acids potentially critical for MP structure and functionality. We performed alanine-scanning mutagenesis of the Ourmia melon virus (OuMV) MP, and studied the effects of amino acid substitutions on MP properties and virus infection. We identified five OuMV mutants that were impaired in systemic infection in Nicotiana benthamiana and Arabidopsis thaliana, and two mutants showing necrosis and pronounced mosaic symptoms, respectively, in N. benthamiana. Green fluorescent protein fusion constructs (GFP:MP) of movement-defective MP alleles failed to localize in distinct foci at the cell wall, whereas a GFP fusion with wild-type MP (GFP:MPwt) mainly co-localized with plasmodesmata and accumulated at the periphery of epidermal cells. The movement-defective mutants also failed to produce tubular protrusions in protoplasts isolated from infected leaves, suggesting a link between tubule formation and the ability of OuMV to move. In addition to providing data to support the importance of specific amino acids for OuMV MP functionality, we predict that these conserved residues might be critical for the correct folding and/or function of the MP of other viral species in the 30K superfamily.
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Affiliation(s)
- Paolo Margaria
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Charles T Anderson
- Department of Biology, Pennsylvania State University, University Park, PA, 16802, USA
| | - Massimo Turina
- Istituto per la Protezione Sostenibile delle Piante, CNR, 10135, Torino, Italy
| | - Cristina Rosa
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, 16802, USA
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Identification of Diverse Mycoviruses through Metatranscriptomics Characterization of the Viromes of Five Major Fungal Plant Pathogens. J Virol 2016; 90:6846-6863. [PMID: 27194764 DOI: 10.1128/jvi.00357-16] [Citation(s) in RCA: 179] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 05/11/2016] [Indexed: 01/01/2023] Open
Abstract
UNLABELLED Mycoviruses can have a marked effect on natural fungal communities and influence plant health and productivity. However, a comprehensive picture of mycoviral diversity is still lacking. To characterize the viromes of five widely dispersed plant-pathogenic fungi, Colletotrichum truncatum, Macrophomina phaseolina, Diaporthe longicolla, Rhizoctonia solani, and Sclerotinia sclerotiorum, a high-throughput sequencing-based metatranscriptomic approach was used to detect viral sequences. Total RNA and double-stranded RNA (dsRNA) from mycelia and RNA from samples enriched for virus particles were sequenced. Sequence data were assembled de novo, and contigs with predicted amino acid sequence similarities to viruses in the nonredundant protein database were selected. The analysis identified 72 partial or complete genome segments representing 66 previously undescribed mycoviruses. Using primers specific for each viral contig, at least one fungal isolate was identified that contained each virus. The novel mycoviruses showed affinity with 15 distinct lineages: Barnaviridae, Benyviridae, Chrysoviridae, Endornaviridae, Fusariviridae, Hypoviridae, Mononegavirales, Narnaviridae, Ophioviridae, Ourmiavirus, Partitiviridae, Tombusviridae, Totiviridae, Tymoviridae, and Virgaviridae More than half of the viral sequences were predicted to be members of the Mitovirus genus in the family Narnaviridae, which replicate within mitochondria. Five viral sequences showed strong affinity with three families (Benyviridae, Ophioviridae, and Virgaviridae) that previously contained no mycovirus species. The genomic information provides insight into the diversity and taxonomy of mycoviruses and coevolution of mycoviruses and their fungal hosts. IMPORTANCE Plant-pathogenic fungi reduce crop yields, which affects food security worldwide. Plant host resistance is considered a sustainable disease management option but may often be incomplete or lacking for some crops to certain fungal pathogens or strains. In addition, the rising issues of fungicide resistance demand alternative strategies to reduce the negative impacts of fungal pathogens. Those fungus-infecting viruses (mycoviruses) that attenuate fungal virulence may be welcome additions for mitigation of plant diseases. By high-throughput sequencing of the RNAs from 275 isolates of five fungal plant pathogens, 66 previously undescribed mycoviruses were identified. In addition to identifying new potential biological control agents, these results expand the grand view of the diversity of mycoviruses and provide possible insights into the importance of intracellular and extracellular transmission in fungus-virus coevolution.
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Turina M, Rossi M, Moretti M. Investigation on the partial resistance of Cpkk2 knock out strain of Cryphonectria parasitica to Cryphonectria hypovirus 1 infection in presence of Geneticin and Geneticin resistance gene. Virus Res 2016; 219:58-61. [PMID: 26643512 DOI: 10.1016/j.virusres.2015.11.022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Revised: 11/18/2015] [Accepted: 11/20/2015] [Indexed: 11/19/2022]
Abstract
We have recently characterized the central components of the three MAP kinase cascades present in Cryphonectria parasitica : the MEK genes cpkk1, cpkk2 and cpkk3. When we attempted to infect through anastomosis the three knock out strains with Cryphonectria hypovirus 1 (CHV1), only the deletion strain of Cpkk2, the yeast Ste7 homologue, involved in mating and filamentous growth, could not be infected. We then proceeded to attempt virus infection through transformation of Δcpkk2 protoplasts using an infectious cDNA clone able to establish virus infection through transformation. In this case, a very limited number of strains could be recovered as stable transformants compared to the efficiency of control transformations with plasmid carrying only the antibiotic marker. Furthermore, transformants carrying actively replicating virus could be isolated only if the selection marker Geneticin was used during the very initial selection process, and not maintained throughout the growth of the colonies. Moreover, Δcpkk2 isolates that maintained the virus lost Geneticin resistance. We therefore unveiled a specific negative interaction among virus infection, presence of Geneticin in the growth media, and lack of Cpkk2 MEK in the fungal host.
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Affiliation(s)
- Massimo Turina
- Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, 10135 Torino, Italy.
| | - Marika Rossi
- Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, 10135 Torino, Italy
| | - Marino Moretti
- Istituto per la Protezione Sostenibile delle Piante, CNR, Strada delle Cacce 73, 10135 Torino, Italy
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Ferriol I, Turina M, Zamora-Macorra EJ, Falk BW. RNA1-Independent Replication and GFP Expression from Tomato marchitez virus Isolate M Cloned cDNA. PHYTOPATHOLOGY 2016; 106:500-509. [PMID: 26756828 DOI: 10.1094/phyto-10-15-0267-r] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Tomato marchitez virus (ToMarV; synonymous with Tomato apex necrosis virus) is a positive-strand RNA virus in the genus Torradovirus within the family Secoviridae. ToMarV is an emergent whitefly-transmitted virus that causes important diseases in tomato (Solanum lycopersicum) in Mexico. Here, the genome sequence of the ToMarV isolate M (ToMarV-M) was determined. We engineered full-length cDNA clones of the ToMarV-M genomic RNA (RNA1 and RNA2), separately, into a binary vector. Coinfiltration of both triggered systemic infections in Nicotiana benthamiana, tomato, and tomatillo (Physalis philadelphica) plants and recapitulated the biological activity of the wild-type virus. The viral progeny generated from tomato and tomatillo plants were transmissible by the whitefly Bemisia tabaci biotype B. Also, we assessed whether these infectious clones could be used for screening tomato cultivars for resistance to ToMarV and our results allowed us to differentiate resistant and susceptible tomato lines. We demonstrated that RNA1 of ToMarV-M is required for the replication of RNA2, and it can replicate independently of RNA2. From this, ToMarV-M RNA2 was used to express the green fluorescent protein in N. benthamiana plants, which allowed us to track cell-to-cell movement. The construction of full-length infectious cDNA clones of ToMarV-M provides an excellent tool to investigate virus-host-vector interactions and elucidate the functions of torradovirus-encoded proteins or the mechanisms of replication of torradovirus genomic RNA.
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Affiliation(s)
- I Ferriol
- First and fourth authors: Plant Pathology Department, University of California Davis, 95616, Davis; second author: Istituto per la Protezione Sostenibile delle Piante, Sez. di Torino, CNR, Turin, Italy; and third author: Colegio de Postgraduados-Campus Montecillo, 56230, Texcoco, Mexico
| | - M Turina
- First and fourth authors: Plant Pathology Department, University of California Davis, 95616, Davis; second author: Istituto per la Protezione Sostenibile delle Piante, Sez. di Torino, CNR, Turin, Italy; and third author: Colegio de Postgraduados-Campus Montecillo, 56230, Texcoco, Mexico
| | - E J Zamora-Macorra
- First and fourth authors: Plant Pathology Department, University of California Davis, 95616, Davis; second author: Istituto per la Protezione Sostenibile delle Piante, Sez. di Torino, CNR, Turin, Italy; and third author: Colegio de Postgraduados-Campus Montecillo, 56230, Texcoco, Mexico
| | - B W Falk
- First and fourth authors: Plant Pathology Department, University of California Davis, 95616, Davis; second author: Istituto per la Protezione Sostenibile delle Piante, Sez. di Torino, CNR, Turin, Italy; and third author: Colegio de Postgraduados-Campus Montecillo, 56230, Texcoco, Mexico
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