The Experts below are selected from a list of 42 Experts worldwide ranked by ideXlab platform
Georgios Vidalakis - One of the best experts on this subject based on the ideXlab platform.
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ICTV Virus Taxonomy Profile: Pospiviroidae.
The Journal of general virology, 2021Co-Authors: Francesco Di Serio, Georgios Vidalakis, Jaroslav Matousek, Vicente Pallás, Robert A. Owens, John W. Randles, Teruo Sano, Jacobus Th. J. Verhoeven, Ricardo FloresAbstract:Members of the family Pospiviroidae have single-stranded circular RNA genomes that adopt a rod-like or a quasi-rod-like conformation. These genomes contain a central conserved region that is involved in replication in the nucleus through an asymmetric RNA-RNA rolling-circle mechanism. Members of the family Pospiviroidae lack the hammerhead ribozymes that are typical of viroids classified in the family Avsunviroidae. The family Pospiviroidae includes the genera Apscaviroid, Cocadviroid, Coleviroid, Hostuviroid and Pospiviroid, with >25 species. This is a summary of the ICTV Report on the family Pospiviroidae, which is available at ictv.global/report/pospiviroidae.
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one step multiplex rt qpcr detects three citrus viroids from different genera in a wide range of hosts
Journal of Virological Methods, 2017Co-Authors: Fatima Osman, Tyler Dang, Sohrab Bodaghi, Georgios VidalakisAbstract:A one-step multiplex reverse transcription real-time quantitative polymerase chain reaction (RT-qPCR) based on species-specific minor groove binding (MGB) probes, was developed for the simultaneous detection, identification, and quantification of three citrus viroids belonging to different genera. Citrus exocortis viroid (Pospiviroid), Hop stunt viroid (Hostuviroid), and Citrus bark cracking viroid (Cocadviroid) cause a variety of maladies in agriculturally significant crops. Therefore, reliable assays for their detection are essential tools for various government and industry organizations implementing disease management programs. Singleplex qPCR primers and MGB probes were designed individually for the detection of the three targeted viroids, and subsequently combined in a one-step multiplex RT-qPCR reaction. A wide host range of woody plants, including citrus, grapevines, apricots, plums and herbaceous plants such as tomato, cucumber, eggplant and chrysanthemum different world regions were used to validate the assay. Single, double and triple viroid infections were identified in the tested samples. The developed multiplex RT-qPCR assay was compared with a previously reported SYBR Green I RT-qPCR for the universal detection of citrus viroids. Both assays accurately identified all citrus viroid infected samples. The multiplex assay complemented the SYBR Green I universal detection assay by differentiating among citrus viroid species in the positive samples. The developed multiplex RT-qPCR assay has the potential to simultaneously detect each targeted viroid and could be used in high throughput screenings for citrus viroids in field surveys, germplasm banks, nurseries and other viroid disease management programs.
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Chapter 26 – Other Cocadviroids
Viroids and Satellites, 2017Co-Authors: Irene Lavagi, Jaroslav Matousek, Georgios VidalakisAbstract:Citrus bark cracking viroid (CBCVd) and the hop latent viroid (HLVd) are members of the genus Cocadviroid of the family Pospiviroidae. Both viroids are globally distributed. CBCVd does not induce any significant disease of citrus but incites bark cracking of sensitive citrus rootstock species and has been associated with a severe disease of hops. HLVd does not induce any acute hop symptoms but causes physiological changes with negative yield and quality effects. Both viroids are readily transmitted by mechanical means, detected by molecular assays, and eliminated from the germplasm using meristematic tissue culture. Comprehensive programs that include the use of viroid-tested propagative materials and sanitary measures are required for the management of CBCVd and HLVd.
Vicente Pallás - One of the best experts on this subject based on the ideXlab platform.
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ICTV Virus Taxonomy Profile: Pospiviroidae.
The Journal of general virology, 2021Co-Authors: Francesco Di Serio, Georgios Vidalakis, Jaroslav Matousek, Vicente Pallás, Robert A. Owens, John W. Randles, Teruo Sano, Jacobus Th. J. Verhoeven, Ricardo FloresAbstract:Members of the family Pospiviroidae have single-stranded circular RNA genomes that adopt a rod-like or a quasi-rod-like conformation. These genomes contain a central conserved region that is involved in replication in the nucleus through an asymmetric RNA-RNA rolling-circle mechanism. Members of the family Pospiviroidae lack the hammerhead ribozymes that are typical of viroids classified in the family Avsunviroidae. The family Pospiviroidae includes the genera Apscaviroid, Cocadviroid, Coleviroid, Hostuviroid and Pospiviroid, with >25 species. This is a summary of the ICTV Report on the family Pospiviroidae, which is available at ictv.global/report/pospiviroidae.
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Hop stunt viroid: A polyphagous pathogenic RNA that has shed light on viroid-host interactions.
Molecular plant pathology, 2020Co-Authors: Joan Marquez-molins, Gustavo Gómez, Vicente PallásAbstract:Hop stunt viroid (HSVd) is the type species of the genus Hostuviroid (family Pospiviroidae). The other species of this genus is Dahlia latent viroid, which presents an identical central conserved region (CCR) but lacks other structural hallmarks present in Hop stunt viroid. HSVd replication occurs in the nucleus through an asymmetric rolling-circle model as in the other members of the family Pospiviroidae, which also includes the genera Pospiviroid, Cocadviroid, Apscaviroid, and Coleoviroid. Hop stunt viroid consists of a single-stranded, circular RNA of 295-303 nucleotides depending on isolates and sequence variants. The most stable secondary structure is a rod-like or quasi-rod-like conformation with two characteristic domains: a CCR and a terminal conserved hairpin similar to that of Cocadviroids. HSVd lacks a terminal conserved region. HSVd infects a very broad range of natural hosts and has been reported to be the causal agent of five different diseases (citrus cachexia, cucumber pale fruit, peach and plum apple apricot distortion, and hop stunt). It is distributed worldwide. HSVd is transmitted mechanically and by seed. © 2020 The Authors. Molecular Plant Pathology published by British Society for Plant Pathology and John Wiley & Sons Ltd.
G. Vidalakis - One of the best experts on this subject based on the ideXlab platform.
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The question of Citrus viroid IV as a Cocadviroid
Archives of Virology, 2005Co-Authors: J. S. Semancik, G. VidalakisAbstract:It has been suggested that Citrus viroid IV (CVd-IV) be classified as a species within the genus Cocadviroid . This relationship was based on the presence of a terminal conserved hairpin (TCH) and absence of a terminal conserved region (TCR) as specific structural motifs in common with isolates of Coconut cadang-cadang viroid (CCCVd) as well as phylogenetic relationships with members of the genus Cocadviroid . Evidence is presented for a “vestigial” TCR in CVd-IV as well as the introduction of the terminal repeat region (TRR) motif and an alternative sequence analysis that suggests a closer phylogenetic relationship of CVd-IV to isolates of Citrus exocortis viroid (CEVd), a species within the genus Pospiviroid than to CCCVd. This position is further supported by the striking similarity of biological properties between CVd-IV and CEVd with the suggestion offered that biological evidence be considered for specific adjustments to any overall classification scheme for viroids.
Deborah A. Golino - One of the best experts on this subject based on the ideXlab platform.
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Discovery of Viruses and Virus-Like Pathogens in Pistachio using High-Throughput Sequencing.
Plant disease, 2018Co-Authors: Maher Al Rwahnih, Adib Rowhani, Nathaniel M. Westrick, Kristian Stevens, Alfredo Diaz-lara, Florent P. Trouillas, John E. Preece, Craig E. Kallsen, Kristen D. Farrar, Deborah A. GolinoAbstract:Pistachio (Pistacia vera L.) trees from the National Clonal Germplasm Repository (NCGR) and orchards in California were surveyed for viruses and virus-like agents by high-throughput sequencing (HTS). Analyses of sequence information from 60 trees identified a novel virus, provisionally named "Pistachio ampelovirus A" (PAVA), in the NCGR that showed low amino acid sequence identity (approximately 42%) compared with members of the genus Ampelovirus (family Closteroviridae). A putative viroid, provisionally named "Citrus bark cracking viroid-pistachio" (CBCVd-pis), was also found in the NCGR and showed approximately 87% similarity to Citrus bark cracking viroid (CBCVd, genus Cocadviroid, family Pospiviroidae). Both PAVA and CBCVd-pis were graft transmissible to healthy UCB-1 hybrid rootstock seedlings (P. atlantica × P. integerrima). A field survey of 123 trees from commercial orchards found no incidence of PAVA but five (4%) samples were infected with CBCVd-pis. Of 675 NCGR trees, 16 (2.3%) were positive for PAVA and 172 (25.4%) were positive for CBCVd-pis by reverse-transcription polymerase chain reaction. Additionally, several contigs across multiple samples exhibited significant sequence similarity to a number of other plant virus species in different families. These findings require further study and confirmation. This study establishes the occurrence of viral and viroid populations infecting pistachio trees.
Jaroslav Matousek - One of the best experts on this subject based on the ideXlab platform.
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ICTV Virus Taxonomy Profile: Pospiviroidae.
The Journal of general virology, 2021Co-Authors: Francesco Di Serio, Georgios Vidalakis, Jaroslav Matousek, Vicente Pallás, Robert A. Owens, John W. Randles, Teruo Sano, Jacobus Th. J. Verhoeven, Ricardo FloresAbstract:Members of the family Pospiviroidae have single-stranded circular RNA genomes that adopt a rod-like or a quasi-rod-like conformation. These genomes contain a central conserved region that is involved in replication in the nucleus through an asymmetric RNA-RNA rolling-circle mechanism. Members of the family Pospiviroidae lack the hammerhead ribozymes that are typical of viroids classified in the family Avsunviroidae. The family Pospiviroidae includes the genera Apscaviroid, Cocadviroid, Coleviroid, Hostuviroid and Pospiviroid, with >25 species. This is a summary of the ICTV Report on the family Pospiviroidae, which is available at ictv.global/report/pospiviroidae.
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Chapter 26 – Other Cocadviroids
Viroids and Satellites, 2017Co-Authors: Irene Lavagi, Jaroslav Matousek, Georgios VidalakisAbstract:Citrus bark cracking viroid (CBCVd) and the hop latent viroid (HLVd) are members of the genus Cocadviroid of the family Pospiviroidae. Both viroids are globally distributed. CBCVd does not induce any significant disease of citrus but incites bark cracking of sensitive citrus rootstock species and has been associated with a severe disease of hops. HLVd does not induce any acute hop symptoms but causes physiological changes with negative yield and quality effects. Both viroids are readily transmitted by mechanical means, detected by molecular assays, and eliminated from the germplasm using meristematic tissue culture. Comprehensive programs that include the use of viroid-tested propagative materials and sanitary measures are required for the management of CBCVd and HLVd.