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Kai-shu Ling - One of the best experts on this subject based on the ideXlab platform.
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A single base pair in the right terminal domain of tomato planta macho Viroid is a virulence determinant factor on tomato.
Virology, 2016Co-Authors: Chellappan Padmanabhan, Kai-shu LingAbstract:Tomato planta macho Viroid (TPMVd), including isolates previously designated as Mexican Papita Viroid (MPVd), causes serious disease on tomatoes in North America. Two predominant variants, sharing 93.8% sequence identity, incited distinct severe (MPVd-S) or mild (MPVd-M) symptoms on tomato. To identify virulence determinant factor, a series of chimeric infectious clones were generated using synthetic DNA approach to progressively replace each structural domain between the two variants. In bioassays on tomato 'Rutgers', three chimeras containing Terminal Left and Pathogenicity (MPVd-H1), Central (MPVd-H2), or Variable (MPVd-H3) of MPVd-S, incited mild to intermediate symptoms. However, a chimera containing Terminal Right (TR) of MPVd-S (MPVd-H4) incited severe symptoms. Only one base-pair mutation in the TR domain between MPVd-M (176U:A185) and MPVd-S (174G:C183) was identified. A reciprocal mutant (MPVd-H5) rendered the chimeric Viroid mild on tomato. This single base-pair in the TR domain was determined as the virulence determinant factor for TPMVd.
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First Report of Potato spindle tuber Viroid Naturally Infecting Field Tomatoes in the Dominican Republic.
Plant disease, 2014Co-Authors: Kai-shu Ling, D. Groth-helms, F. M. Assis-filhoAbstract:In recent years, Viroid disease outbreaks have resulted in serious economic losses to a number of tomato growers in North America (1,2,3). At least three pospiViroids have been identified as the causal agents of tomato disease, including Potato spindle tuber Viroid (PSTVd), Tomato chlorotic dwarf Viroid (TCDVd), and Mexican Papita Viroid (MPVd). In the spring of 2013, a severe disease outbreak with virus-like symptoms (chlorosis and plant stunting) was observed in a tomato field located in the Dominican Republic, whose tomato production is generally exported to the United States in the winter months. The transplants were produced in house. The disease has reached an epidemic level with many diseased plants pulled and disposed of accordingly. Three samples collected in May of 2013 were screened by ELISA against 16 common tomato viruses (Alfalfa mosaic virus, Cucumber mosaic virus, Impatiens necrotic spot virus, Pepino mosaic virus, Potato virus X, Potato virus Y, Tobacco etch virus, Tobacco mosaic virus, T...
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First Report of 'Candidatus Liberibacter solanacearum' Naturally Infecting Tomatoes in the State of Mexico, Mexico.
Plant disease, 2011Co-Authors: Kai-shu Ling, W. Zhang, Hong Lin, M. L. Lewis Ivey, Sally A. MillerAbstract:In January 2011, tomato (Solanum lycopersicum) plants exhibiting stunting, yellow mosaic, short, chlorotic leaves, aborted flowers, and reduced-size fruits, symptoms similar to those exhibited by plants infected by ‘Candidatus Liberibacter solanacearum’ (2), were observed in approximately 5% of tomato plants in greenhouses in Jocotitlan in the State of Mexico, Mexico. Occasional plant recovery was also observed. Tomato plants in this facility were previously shown to be infected by Mexican Papita Viroid (MPVd), Pepino mosaic virus (PepMV), and aster yellows phytoplasma. Eight symptomatic leaf samples (designated MX11-01 to MX11-08) were collected and screened against selected tomato viruses and pospiViroids by reverse transcription (RT)-PCR using purified plant RNA or for ‘Ca. L. solanacearum’ by PCR using purified plant DNA. As expected, both PepMV and MPVd were detected in these samples. However, two ‘Ca. L. solanacearum’-specific PCR products (1,168 and 669 bp) were also amplified in two samples (MX11-...
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First Report of Mexican Papita Viroid Infecting Greenhouse Tomato in Canada
Plant disease, 2009Co-Authors: Kai-shu Ling, M. E. BledsoeAbstract:In the summer of 2008, tomato (Solanum lycopersicum) plants in a large greenhouse tomato facility located in Delta, British Columbia, Canada exhibited general stunting, chlorosis, and purple-leaf symptoms that were distinct from those of Pepino mosaic virus (PepMV) (1). Diseased plants were localized mainly in two rows in a section of the greenhouse and produced no fruits or only fruits with reduced size. Leaf samples were collected from four individuals among numerous diseased plants in this greenhouse. Screening samples by ELISA, PCR, or reverse transcription (RT)-PCR for PepMV, Tomato spotted wilt virus, Tomato yellow leaf curl virus, Tomato torrado virus, Tomato apex necrosis virus, and Begomovirus, Tobamovirus, and PospiViroid species showed that all four plants had a mixed infection of both PepMV and a pospiViroid. RT-PCR with the pospiViroid-specific primers Pospil-RE and Pospil-FW (3) amplified the expected 196-bp products from these four samples. Each amplicon was cloned into the pCR4-TOPO vector (Invitrogen, Carlsbad, CA) and one individual cDNA clone from each isolate was sequenced. BLASTN analyses of nucleotide sequences of these clones showed 97 to 99% identity to Mexican Papita Viroid (MPVd) isolates currently in the NCBI Genbank. These four newly identified MPVd isolates were not identical; seven nucleotide substitutions or indels were identified in this region. The full Viroid genome was obtained by RT-PCR in isolate VF2 with a new reverse primer MPVd-RE (5' GATCCCTGAAGCGCTCCT 3') in combination with the forward primer Pospil-FW (3). Using the same approach as stated above, this amplicon was cloned and sequenced. The nucleotide sequence of the 196-nt amplicon previously amplified and cloned from the isolate VF2 genome was identical to this region in the genomic clone. BLASTN analysis showed that the VF2 genome (GenBank Accession No. FJ824844) had >98% sequence identity to each of nine MPVd isolates (GenBank Accession Nos. L78454 and L78456-L78463), 94% identity to Tomato planta macho Viroid (TPMVd) (GenBank Accession No. K00817) and ~80% identity to Tomato chlorotic dwarf Viroid (GenBank Accession Nos. EF582392-EF582393). Prior to this find, MPVd had been identified only in Papita (Solanum cardiophyllum) in Mexico and is considered a possible ancestor of TPMVd, Potato spindle tuber Viroid (PSTVd), and possibly of other PSTVd-group Viroids now infecting crop plants (2). The origin of MPVd in this greenhouse facility in Delta, British Columbia is unknown. The infected plants were destroyed by the grower. The pathogenicity of MPVd isolates characterized in this study was not evaluated on tomato because of quarantine regulations governing this Viroid in the United States. The identification of MPVd infecting an important agricultural crop (tomato) outside its center of origin in Mexico indicates a potentially important major shift in the epidemiology of MPVd. To our knowledge this is the first report of MPVd from tomato in Canada. References: (1). K.-S. Ling et al. Plant Dis. 92:1683, 2008. (2) J. P. Martinez-Soriano et al. Proc. Natl. Acad. Sci. U.S.A. 93:9397, 1996. (3) J. Th. J. Verhoeven et al. Eur. J. Plant Pathol. 110:823, 2004.
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First Report of a Natural Infection by Mexican Papita Viroid and Tomato Chlorotic Dwarf Viroid on Greenhouse Tomatoes in Mexico.
Plant disease, 2009Co-Authors: Kai-shu Ling, W. ZhangAbstract:In early 2008, tomato plants (Solanum lycopersicum) grown in a large greenhouse facility located near Mexico City exhibited general stunting, leaf chlorosis at the top of the diseased plant that later turned bronze or purple, and reduced-sized fruits. Initially, diseased plants were confined to a 5-ha greenhouse, but the disease quickly spread to two additional 5-ha greenhouses in the summer of 2008. By the end of 2008, approximately 5% of tomato plants in 35-ha of greenhouse were infected. Sixteen diseased samples were collected, twelve in 2008 and four in 2009. Bioassays through mechanical inoculation with leaf extracts of diseased samples demonstrated the transmissibility of the causal agent to plants of tomato cvs. Horizon or Rutgers, which expressed symptoms that were similar to those on the source plants. Serological or PCR assays were negative for several commonly occurring greenhouse tomato viruses. However, an expected size product (~196 bp) was consistently detected by reverse transcription (RT)-PCR using pospiViroid-specific primers Pospil-RE and Pospil-FW (4) in all symptomatic samples or from the mechanically inoculated tomato plants. Preliminary analysis with sequences obtained from direct sequencing of amplicons revealed one dominant sequence with 94% identity to Mexican Papita Viroid (MPVd) (GenBank Accessions Nos. L78454 and L78456-L78463). However, further analysis of the cloned cDNAs indicated a mixed infection of two pospiViroids in two samples. Of 10 cDNA clones analyzed, 9 were MPVd-like sequences and one was sequence of Tomato chlorotic dwarf Viroid (TCDVd). Further analysis using full genomic sequences obtained by RT-PCR with previously designed primers (2) or a new set of primers (MTTVd-F: 5' GGG GAA ACC TGG AGC GAA CTG G, and MTTVd-R: 5' GGG GAT CCC TGA AGC GCT CCT) revealed genetic diversity in this population. Eight of thirteen cloned cDNAs represented by the 359-nt sequence of isolate Mex8 (GenBank Accession No. GQ131572) had 93 to 94% nucleotide sequence identity to other MPVd isolates (L78454 and L78456-L78463). Five other cDNA clones represented by the 361-nt sequence of isolate HM2 (GenBank Accession No. GQ131573) were 99% identical to a TCDVd isolate recently identified in Arizona (GenBank Accession No. FJ822878) and 96 to 97% identical to TCDVd isolates from other areas (GenBank Accession Nos. AF162131 and AB329668). These results are the first evidence of a mixed infection of two Viroids infecting tomatoes in Mexico. MPVd was first identified in Mexico on Papita (S. cardiophyllum) in 1996 (1). The origin of TCDVd in this greenhouse was not determined, but TCDVd potentially can be seed transmitted in tomato (3). The close relationship between the Mexican and the U.S. isolates suggests that TCDVd in these two countries may share a common origin, likely from seed. To our knowledge, this is the first report of a natural infection of MPVd and TCDVd on tomatoes in Mexico. References: (1) J. P. Martinez-Soriano et al. Proc. Natl. Acad. Sci. U.S.A. 93:9397, 1996. (2) A. M. Shamloul et al. Can. J. Plant Pathol. 19:89, 1997. (3) R. P. Singh and A. D. Dilworth. Eur. J. Plant Pathol. 123:111, 2009. (4) J. Th. J. Verhoeven et al. Eur. J. Plant Pathol. 110:823, 2004.
J W Roenhorst - One of the best experts on this subject based on the ideXlab platform.
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Development and validation of a real-time RT-PCR test for screening pepper and tomato seed lots for the presence of pospiViroids.
PloS one, 2020Co-Authors: Marleen Botermans, J W Roenhorst, Jacobus Th J Verhoeven, M. Hooftman, Eveline Metz, Esther J. Van Veen, Bart P. J. Geraats, Mark Kemper, Debora C. M. Beugelsdijk, Harrie KoenraadtAbstract:Potato spindle tuber Viroid and other pospiViroids can cause serious diseases in potato and tomato crops. Consequently, pospiViroids are regulated in several countries. Since seed transmission is considered as a pathway for the introduction and spread of pospiViroids, some countries demand for the testing of seed lots of solanaceous crops for the presence of pospiViroids. A real-time RT-PCR test, named PospiSense, was developed for testing pepper (Capsicum annuum) and tomato (Solanum lycopersicum) seeds for seven pospiViroid species known to occur naturally in these crops. The test consists of two multiplex reactions running in parallel, PospiSense 1 and PospiSense 2, that target Citrus exocortis Viroid (CEVd), Columnea latent Viroid (CLVd), pepper chat fruit Viroid (PCFVd), potato spindle tuber Viroid (PSTVd), tomato apical stunt Viroid (TASVd), tomato chlorotic dwarf Viroid (TCDVd) and tomato planta macho Viroid (TPMVd, including the former Mexican Papita Viroid). Dahlia latent Viroid (DLVd) is used as an internal isolation control. Validation of the test showed that for both pepper and tomato seeds the current requirements of a routine screening test are fulfilled, i.e. the ability to detect one infested seed in a sample of c.1000 seeds for each of these seven pospiViroids. Additionally, the PospiSense test performed well in an inter-laboratory comparison, which included two routine seed-testing laboratories, and as such provides a relatively easy alternative to the currently used tests.
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Mexican Papita Viroid and tomato planta macho Viroid belong to a single species in the genus PospiViroid
Archives of Virology, 2011Co-Authors: J.th.j. Verhoeven, J W Roenhorst, Robert A OwensAbstract:Tomato planta macho Viroid (TPMVd) and Mexican Papita Viroid (MPVd) are two closely related (>90% sequence identity) members of the genus PospiViroid. Their current status as members of separate species is based upon the reported ability of TPMVd to replicate in Gomphrena globosa and the inability of this Viroid to evoke flower break in N. glutinosa. Characterization of a Viroid recently isolated from diseased tomato plants grown in Mexico (identical to GenBank accession GQ131573) casts doubt on this earlier report and indicates that these Viroids should be classified as members of a single species. Giving priority to the older name, we propose including both of these Viroids in the current species Tomato planta macho Viroid.
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First Report of Potato spindle tuber Viroid in Cape Gooseberry (Physalis peruviana) from Turkey and Germany
Plant disease, 2009Co-Authors: J.th.j. Verhoeven, J W Roenhorst, M. Botermans, J. Westerhof, E. T. M. MeekesAbstract:Since the recent identification of Potato spindle tuber Viroid (PSTVd) in vegetatively propagated ornamental plant species (4), many growers have asked to have their mother plants tested for this Viroid. In December of 2007, a grower from Turkey submitted cuttings of cape gooseberry (Physalis peruviana) to be tested for PSTVd. Initial testing by real-time reverse transcription (RT)-PCR according to Boonham et al. (1) indicated the presence of either Mexican Papita Viroid, PSTVd, or Tomato chlorotic dwarf Viroid in four samples. To identify the Viroid(s) present, isolated RNA from these samples was used for RT-PCR (2), and products of the expected full genome size for the three Viroids were amplified from each sample. One of the PCR products was sequenced (GenBank Accession No. EU862230) and analysis of the 357 nt sequence indicated it was most related to PSTVd sequences belonging to the so-called ‘Oceanian’ strain of the Viroid (3), with 99.7% identity to GenBank Accession No. AY962324. Therefore, the vir...
J.th.j. Verhoeven - One of the best experts on this subject based on the ideXlab platform.
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Mexican Papita Viroid and tomato planta macho Viroid belong to a single species in the genus PospiViroid
Archives of Virology, 2011Co-Authors: J.th.j. Verhoeven, J W Roenhorst, Robert A OwensAbstract:Tomato planta macho Viroid (TPMVd) and Mexican Papita Viroid (MPVd) are two closely related (>90% sequence identity) members of the genus PospiViroid. Their current status as members of separate species is based upon the reported ability of TPMVd to replicate in Gomphrena globosa and the inability of this Viroid to evoke flower break in N. glutinosa. Characterization of a Viroid recently isolated from diseased tomato plants grown in Mexico (identical to GenBank accession GQ131573) casts doubt on this earlier report and indicates that these Viroids should be classified as members of a single species. Giving priority to the older name, we propose including both of these Viroids in the current species Tomato planta macho Viroid.
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First Report of Potato spindle tuber Viroid in Cape Gooseberry (Physalis peruviana) from Turkey and Germany
Plant disease, 2009Co-Authors: J.th.j. Verhoeven, J W Roenhorst, M. Botermans, J. Westerhof, E. T. M. MeekesAbstract:Since the recent identification of Potato spindle tuber Viroid (PSTVd) in vegetatively propagated ornamental plant species (4), many growers have asked to have their mother plants tested for this Viroid. In December of 2007, a grower from Turkey submitted cuttings of cape gooseberry (Physalis peruviana) to be tested for PSTVd. Initial testing by real-time reverse transcription (RT)-PCR according to Boonham et al. (1) indicated the presence of either Mexican Papita Viroid, PSTVd, or Tomato chlorotic dwarf Viroid in four samples. To identify the Viroid(s) present, isolated RNA from these samples was used for RT-PCR (2), and products of the expected full genome size for the three Viroids were amplified from each sample. One of the PCR products was sequenced (GenBank Accession No. EU862230) and analysis of the 357 nt sequence indicated it was most related to PSTVd sequences belonging to the so-called ‘Oceanian’ strain of the Viroid (3), with 99.7% identity to GenBank Accession No. AY962324. Therefore, the vir...
F. M. Assis-filho - One of the best experts on this subject based on the ideXlab platform.
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First Report of Potato spindle tuber Viroid Naturally Infecting Field Tomatoes in the Dominican Republic.
Plant disease, 2014Co-Authors: Kai-shu Ling, D. Groth-helms, F. M. Assis-filhoAbstract:In recent years, Viroid disease outbreaks have resulted in serious economic losses to a number of tomato growers in North America (1,2,3). At least three pospiViroids have been identified as the causal agents of tomato disease, including Potato spindle tuber Viroid (PSTVd), Tomato chlorotic dwarf Viroid (TCDVd), and Mexican Papita Viroid (MPVd). In the spring of 2013, a severe disease outbreak with virus-like symptoms (chlorosis and plant stunting) was observed in a tomato field located in the Dominican Republic, whose tomato production is generally exported to the United States in the winter months. The transplants were produced in house. The disease has reached an epidemic level with many diseased plants pulled and disposed of accordingly. Three samples collected in May of 2013 were screened by ELISA against 16 common tomato viruses (Alfalfa mosaic virus, Cucumber mosaic virus, Impatiens necrotic spot virus, Pepino mosaic virus, Potato virus X, Potato virus Y, Tobacco etch virus, Tobacco mosaic virus, T...
W. Zhang - One of the best experts on this subject based on the ideXlab platform.
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First Report of 'Candidatus Liberibacter solanacearum' Naturally Infecting Tomatoes in the State of Mexico, Mexico.
Plant disease, 2011Co-Authors: Kai-shu Ling, W. Zhang, Hong Lin, M. L. Lewis Ivey, Sally A. MillerAbstract:In January 2011, tomato (Solanum lycopersicum) plants exhibiting stunting, yellow mosaic, short, chlorotic leaves, aborted flowers, and reduced-size fruits, symptoms similar to those exhibited by plants infected by ‘Candidatus Liberibacter solanacearum’ (2), were observed in approximately 5% of tomato plants in greenhouses in Jocotitlan in the State of Mexico, Mexico. Occasional plant recovery was also observed. Tomato plants in this facility were previously shown to be infected by Mexican Papita Viroid (MPVd), Pepino mosaic virus (PepMV), and aster yellows phytoplasma. Eight symptomatic leaf samples (designated MX11-01 to MX11-08) were collected and screened against selected tomato viruses and pospiViroids by reverse transcription (RT)-PCR using purified plant RNA or for ‘Ca. L. solanacearum’ by PCR using purified plant DNA. As expected, both PepMV and MPVd were detected in these samples. However, two ‘Ca. L. solanacearum’-specific PCR products (1,168 and 669 bp) were also amplified in two samples (MX11-...
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First Report of a Natural Infection by Mexican Papita Viroid and Tomato Chlorotic Dwarf Viroid on Greenhouse Tomatoes in Mexico.
Plant disease, 2009Co-Authors: Kai-shu Ling, W. ZhangAbstract:In early 2008, tomato plants (Solanum lycopersicum) grown in a large greenhouse facility located near Mexico City exhibited general stunting, leaf chlorosis at the top of the diseased plant that later turned bronze or purple, and reduced-sized fruits. Initially, diseased plants were confined to a 5-ha greenhouse, but the disease quickly spread to two additional 5-ha greenhouses in the summer of 2008. By the end of 2008, approximately 5% of tomato plants in 35-ha of greenhouse were infected. Sixteen diseased samples were collected, twelve in 2008 and four in 2009. Bioassays through mechanical inoculation with leaf extracts of diseased samples demonstrated the transmissibility of the causal agent to plants of tomato cvs. Horizon or Rutgers, which expressed symptoms that were similar to those on the source plants. Serological or PCR assays were negative for several commonly occurring greenhouse tomato viruses. However, an expected size product (~196 bp) was consistently detected by reverse transcription (RT)-PCR using pospiViroid-specific primers Pospil-RE and Pospil-FW (4) in all symptomatic samples or from the mechanically inoculated tomato plants. Preliminary analysis with sequences obtained from direct sequencing of amplicons revealed one dominant sequence with 94% identity to Mexican Papita Viroid (MPVd) (GenBank Accessions Nos. L78454 and L78456-L78463). However, further analysis of the cloned cDNAs indicated a mixed infection of two pospiViroids in two samples. Of 10 cDNA clones analyzed, 9 were MPVd-like sequences and one was sequence of Tomato chlorotic dwarf Viroid (TCDVd). Further analysis using full genomic sequences obtained by RT-PCR with previously designed primers (2) or a new set of primers (MTTVd-F: 5' GGG GAA ACC TGG AGC GAA CTG G, and MTTVd-R: 5' GGG GAT CCC TGA AGC GCT CCT) revealed genetic diversity in this population. Eight of thirteen cloned cDNAs represented by the 359-nt sequence of isolate Mex8 (GenBank Accession No. GQ131572) had 93 to 94% nucleotide sequence identity to other MPVd isolates (L78454 and L78456-L78463). Five other cDNA clones represented by the 361-nt sequence of isolate HM2 (GenBank Accession No. GQ131573) were 99% identical to a TCDVd isolate recently identified in Arizona (GenBank Accession No. FJ822878) and 96 to 97% identical to TCDVd isolates from other areas (GenBank Accession Nos. AF162131 and AB329668). These results are the first evidence of a mixed infection of two Viroids infecting tomatoes in Mexico. MPVd was first identified in Mexico on Papita (S. cardiophyllum) in 1996 (1). The origin of TCDVd in this greenhouse was not determined, but TCDVd potentially can be seed transmitted in tomato (3). The close relationship between the Mexican and the U.S. isolates suggests that TCDVd in these two countries may share a common origin, likely from seed. To our knowledge, this is the first report of a natural infection of MPVd and TCDVd on tomatoes in Mexico. References: (1) J. P. Martinez-Soriano et al. Proc. Natl. Acad. Sci. U.S.A. 93:9397, 1996. (2) A. M. Shamloul et al. Can. J. Plant Pathol. 19:89, 1997. (3) R. P. Singh and A. D. Dilworth. Eur. J. Plant Pathol. 123:111, 2009. (4) J. Th. J. Verhoeven et al. Eur. J. Plant Pathol. 110:823, 2004.