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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, Jacobus Th J Verhoeven, Jaroslav Matousek, Robert A Owens, Teruo Sano, Vicente Pallás, John W. Randles, 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.
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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:TAXONOMY: 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. PHYSICAL PROPERTIES: 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. HOSTS AND SYMPTOMS: 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. TRANSMISSION: HSVd is transmitted mechanically and by seed.
Dongmei Jiang - One of the best experts on this subject based on the ideXlab platform.
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Microarray hybridization pseudo-color image of the infected citrus sample.
2013Co-Authors: Yongjiang Zhang, Dongmei Jiang, Jun Yin, Yanyan Xin, Fang Ding, Ziniu Deng, Guoping WangAbstract:Eight probes were designed for Hostuviroid and spotted on the microarray in triplicate. These probes are highlighted on the image. Seven out of the eight Hostuviroid probes were positive. Hop stunt viroid was predicted as the major pathogen of the infected citrus sample. No other viroid probe was positive on the microarray. HEX, positive control (PC) and negative control (NC) are marked on the image.
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Sensitivity test of HSVd.
2013Co-Authors: Yongjiang Zhang, Dongmei Jiang, Jun Yin, Yanyan Xin, Fang Ding, Ziniu Deng, Guoping WangAbstract:Microarray hybridization pseudo-color images were generated for RNA dilutions of (A) 100, (B) 101, (C) 102 and (D) 103 fold. Control probes and probes targeting Hostuviroid are highlighted with rectangles. (E) RT-PCR was performed for different RNA dilutions and a negative control. HEX was used as an internal control to monitor ligation efficiency. PC, positive control. NC, negative control.
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Simultaneous Detection of Three Viroid Species Infecting Hops in China by Multiplex RT-PCR
Journal of Phytopathology, 2012Co-Authors: Zhixiang Zhang, Shengxue Liu, Hongqing Wang, Dongmei JiangAbstract:We have developed a multiplex RT-PCR protocol for the simultaneous detection of three viroids in three different genera that infect hops: Hop latent viroid (HLVd; Cocadviroid), Hop stunt viroid (HSVd; Hostuviroid )a ndApple fruit crinkle viroid (AFCVd; Apscaviroid). The method was validated by testing 175 hop samples collected from the Xinjiang autonomous region of China. All samples were found to be positive for HLVd but negative for AFCVd, confirming the widespread or even ubiquitous infection of HLVd and the low incidence of AFCVd in hops in China. In addition, HSVd was detected in 22.86% of the samples tested. This rapid and reliable multiplex RT-PCR assay provides an effective method for detection of three important viroid species in large-scale surveys for disease management in hops.
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Molecular characterization of a member of a new species of grapevine viroid
Archives of virology, 2009Co-Authors: Dongmei Jiang, Rui Guo, Hongqing WangAbstract:Currently, viroids of five species are known to infect grapevine trees: Hop stunt viroid (HSVd-g) [1], Citrus exocortis viroid (CEVd-g) [2], Australian grapevine viroid (AGVd) [3], Grapevine yellow speckle viroid 1 (GYSVd-1) and Grapevine yellow speckle viroid 2 (GYSVd-2) [4–6]. These five grapevine viroid species have been divided into three genera based on sequence homologies of their central conserved regions (CCRs) [7]. GYSVd-1, GYSVd-2, and AGVd are classified in the genus Apscaviroid, whereas HSVd-g [8] and CEVd-g are classified in the genera Hostuviroid and Pospiviroid, respectively [9]. Mixed infections involving these viroids in cultivated grapevines are common, and in general, grapevine viroids produce very few, if any, disease symptoms. In the absence of manifested disease symptoms, these viroids are able to replicate in a host unnoticed. Of the five grapevine viroids identified, GYSVd-1 and GYSVd-2 are associated with disease symptoms such as yellow speckle, which was originally identified under hot greenhouse conditions in Australia [4, 5, 10]. Taylor and Woodham first described yellow speckle (YS) disease in Australia, and it is still the only grapevine disease known to be caused by viroids [10]. GYSVd-1, which is approximately 367 nucleotides (nts) in length, was first isolated from the grapevine cultivar ‘Cabernet Franc’, showing typical symptoms of YS disease. From this cultivar, a single circular RNA was isolated by two-dimensional electrophoresis [4]. GYSVd-2, which is approximately 363 nts in length, was first purified from the grapevine cultivar ‘Kyoto’, which was grafted onto the ‘Dogridge’ rootstock and also exhibited symptoms of YS disease [5]. So far, GYSVd-2 has only been reported in Australia and China [5, 6], and the molecular characterization of GYSVd-2 has been described [11]. Here, we report the characterization of a member of a species of grapevine viroid isolated from China. We call it Chinese grapevine viroid (CGVd) in this report and suggest tentatively naming it Grapevine yellow speckle viroid (GYSVd-3) based on the results of sequence, phylogenetic analysis and molecular characterization.
Hongqing Wang - One of the best experts on this subject based on the ideXlab platform.
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Simultaneous Detection of Three Viroid Species Infecting Hops in China by Multiplex RT-PCR
Journal of Phytopathology, 2012Co-Authors: Zhixiang Zhang, Shengxue Liu, Hongqing Wang, Dongmei JiangAbstract:We have developed a multiplex RT-PCR protocol for the simultaneous detection of three viroids in three different genera that infect hops: Hop latent viroid (HLVd; Cocadviroid), Hop stunt viroid (HSVd; Hostuviroid )a ndApple fruit crinkle viroid (AFCVd; Apscaviroid). The method was validated by testing 175 hop samples collected from the Xinjiang autonomous region of China. All samples were found to be positive for HLVd but negative for AFCVd, confirming the widespread or even ubiquitous infection of HLVd and the low incidence of AFCVd in hops in China. In addition, HSVd was detected in 22.86% of the samples tested. This rapid and reliable multiplex RT-PCR assay provides an effective method for detection of three important viroid species in large-scale surveys for disease management in hops.
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Molecular characterization of a member of a new species of grapevine viroid
Archives of virology, 2009Co-Authors: Dongmei Jiang, Rui Guo, Hongqing WangAbstract:Currently, viroids of five species are known to infect grapevine trees: Hop stunt viroid (HSVd-g) [1], Citrus exocortis viroid (CEVd-g) [2], Australian grapevine viroid (AGVd) [3], Grapevine yellow speckle viroid 1 (GYSVd-1) and Grapevine yellow speckle viroid 2 (GYSVd-2) [4–6]. These five grapevine viroid species have been divided into three genera based on sequence homologies of their central conserved regions (CCRs) [7]. GYSVd-1, GYSVd-2, and AGVd are classified in the genus Apscaviroid, whereas HSVd-g [8] and CEVd-g are classified in the genera Hostuviroid and Pospiviroid, respectively [9]. Mixed infections involving these viroids in cultivated grapevines are common, and in general, grapevine viroids produce very few, if any, disease symptoms. In the absence of manifested disease symptoms, these viroids are able to replicate in a host unnoticed. Of the five grapevine viroids identified, GYSVd-1 and GYSVd-2 are associated with disease symptoms such as yellow speckle, which was originally identified under hot greenhouse conditions in Australia [4, 5, 10]. Taylor and Woodham first described yellow speckle (YS) disease in Australia, and it is still the only grapevine disease known to be caused by viroids [10]. GYSVd-1, which is approximately 367 nucleotides (nts) in length, was first isolated from the grapevine cultivar ‘Cabernet Franc’, showing typical symptoms of YS disease. From this cultivar, a single circular RNA was isolated by two-dimensional electrophoresis [4]. GYSVd-2, which is approximately 363 nts in length, was first purified from the grapevine cultivar ‘Kyoto’, which was grafted onto the ‘Dogridge’ rootstock and also exhibited symptoms of YS disease [5]. So far, GYSVd-2 has only been reported in Australia and China [5, 6], and the molecular characterization of GYSVd-2 has been described [11]. Here, we report the characterization of a member of a species of grapevine viroid isolated from China. We call it Chinese grapevine viroid (CGVd) in this report and suggest tentatively naming it Grapevine yellow speckle viroid (GYSVd-3) based on the results of sequence, phylogenetic analysis and molecular characterization.
J W Roenhorst - One of the best experts on this subject based on the ideXlab platform.
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Dahlia Latent Viroid
Viroids and Satellites, 2017Co-Authors: Jacobus Th J Verhoeven, J W Roenhorst, E. T. M. Meekes, Ricardo Flores, P SerraAbstract:Abstract Dahlia latent viroid (DLVd) displays features characteristic of members of the family Pospiviroidae; i.e., a predicted rod-like conformation with a central conserved region and a terminal conserved region. Allocation to a genus is more complicated since the central conserved region is identical to that of hop stunt viroid (HSVd), genus Hostuviroid, whereas the terminal conserved region is typical of members of the genus Pospiviroid. Phylogenetic analysis does not help either because DLVd is most closely related to two species of each genus; i.e., HSVd and pepper chat fruit viroid (genus Pospiviroid). DLVd has been allocated to the genus Hostuviroid because of a common central conserved region with the type species of this genus. Dahlia is the only known host of the viroid. Infected plants are symptomless. Consequently, the economic impact is low.
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dahlia latent viroid a recombinant new species of the family pospiviroidae posing intriguing questions about its origin and classification
Journal of General Virology, 2013Co-Authors: Jacobus Th J Verhoeven, J W Roenhorst, E. T. M. Meekes, Ricardo Flores, P SerraAbstract:A viroid-like RNA has been detected in two asymptomatic dahlia accessions by return and double PAGE. It appeared smaller than Chrysanthemum stunt viroid and Potato spindle tuber viroid, the two members of the genus Pospiviroid, family Pospiviroidae, reported in this ornamental previously. RT-PCR with primers designed for amplifying all pospiviroids produced no amplicons, but RT-PCR with random primers revealed a 342 nt RNA. The sequence of this RNA was confirmed with specific primers, which additionally revealed its presence in many dahlia cultivars. The RNA was named Dahlia latent viroid (DLVd) because it replicates autonomously, but symptomlessly, in dahlia and shares maximum sequence identity with other viroids of less than 56 %. Furthermore, DLVd displays characteristic features of the family Pospiviroidae: a predicted rod-like secondary structure of minimum free energy with a central conserved region (CCR), and the ability to form the metastable structures hairpins I and II. Its CCR is identical to that of Hop stunt viroid (HSVd, genus Hostuviroid). However, DLVd: (i) has the terminal conserved region present in members of the genus Pospiviroid, but absent in HSVd, and (ii) lacks the terminal conserved hairpin present in HSVd. Phylogenetic reconstructions indicate that HSVd and Pepper chat fruit viroid (genus Pospiviroid) are the closest relatives of DLVd, but DLVd differs from these viroids in its host range, restricted to dahlia so far. Therefore, while DLVd fulfils the criteria to be a novel species of the family Pospiviroidae, its recombinant origin makes assignment to the genera Pospiviroid or Hostuviroid problematic.
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natural infections of tomato by citrus exocortis viroid columnea latent viroid potato spindle tuber viroid and tomato chlorotic dwarf viroid
European Journal of Plant Pathology, 2004Co-Authors: Th J J Verhoeven, C C C Jansen, T M Willemen, Robert A Owens, J W RoenhorstAbstract:Since 1988, viroids have been occasionally detected in samples of tomato (Lycopersicon esculentum) originating both in the Netherlands and other countries. Infected plants showed chlorosis, bronzing, leaf distortion and growth reduction. Initial diagnosis of these viroids was by return-polyacrylamide gel electrophoresis, which did not allow a further identification. This paper reports the identification of these viroids by reverse transcription-polymerase chain reaction and sequence analysis. Three known viroids of tomato, i.e. Citrus exocortis viroid, Potato spindle tuber viroid and Tomato chlorotic dwarf viroid were identified. In addition, six isolates were identified as Columnea latent viroid, a viroid so far only detected in some ornamental species. Like the isolates previously isolated from ornamental species, the isolates from tomato share genetic characteristics of both the genera Hostuviroid and Pospiviroid. The biological characteristics of all four viroids, especially their potential effects on both potato (Solanum tuberosum) and tomato, stress the need for reconsideration of their phytosanitary risks.
Jacobus Th J Verhoeven - 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, Jacobus Th J Verhoeven, Jaroslav Matousek, Robert A Owens, Teruo Sano, Vicente Pallás, John W. Randles, 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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Dahlia Latent Viroid
Viroids and Satellites, 2017Co-Authors: Jacobus Th J Verhoeven, J W Roenhorst, E. T. M. Meekes, Ricardo Flores, P SerraAbstract:Abstract Dahlia latent viroid (DLVd) displays features characteristic of members of the family Pospiviroidae; i.e., a predicted rod-like conformation with a central conserved region and a terminal conserved region. Allocation to a genus is more complicated since the central conserved region is identical to that of hop stunt viroid (HSVd), genus Hostuviroid, whereas the terminal conserved region is typical of members of the genus Pospiviroid. Phylogenetic analysis does not help either because DLVd is most closely related to two species of each genus; i.e., HSVd and pepper chat fruit viroid (genus Pospiviroid). DLVd has been allocated to the genus Hostuviroid because of a common central conserved region with the type species of this genus. Dahlia is the only known host of the viroid. Infected plants are symptomless. Consequently, the economic impact is low.
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dahlia latent viroid a recombinant new species of the family pospiviroidae posing intriguing questions about its origin and classification
Journal of General Virology, 2013Co-Authors: Jacobus Th J Verhoeven, J W Roenhorst, E. T. M. Meekes, Ricardo Flores, P SerraAbstract:A viroid-like RNA has been detected in two asymptomatic dahlia accessions by return and double PAGE. It appeared smaller than Chrysanthemum stunt viroid and Potato spindle tuber viroid, the two members of the genus Pospiviroid, family Pospiviroidae, reported in this ornamental previously. RT-PCR with primers designed for amplifying all pospiviroids produced no amplicons, but RT-PCR with random primers revealed a 342 nt RNA. The sequence of this RNA was confirmed with specific primers, which additionally revealed its presence in many dahlia cultivars. The RNA was named Dahlia latent viroid (DLVd) because it replicates autonomously, but symptomlessly, in dahlia and shares maximum sequence identity with other viroids of less than 56 %. Furthermore, DLVd displays characteristic features of the family Pospiviroidae: a predicted rod-like secondary structure of minimum free energy with a central conserved region (CCR), and the ability to form the metastable structures hairpins I and II. Its CCR is identical to that of Hop stunt viroid (HSVd, genus Hostuviroid). However, DLVd: (i) has the terminal conserved region present in members of the genus Pospiviroid, but absent in HSVd, and (ii) lacks the terminal conserved hairpin present in HSVd. Phylogenetic reconstructions indicate that HSVd and Pepper chat fruit viroid (genus Pospiviroid) are the closest relatives of DLVd, but DLVd differs from these viroids in its host range, restricted to dahlia so far. Therefore, while DLVd fulfils the criteria to be a novel species of the family Pospiviroidae, its recombinant origin makes assignment to the genera Pospiviroid or Hostuviroid problematic.