Comparative sequence studies of variants of avocado sunblotch viroid

Rakowski, A. G.; Symons, Robert H.

doi:10.1016/0042-6822(89)90256-0

Cited by 34 publications

(36 citation statements)

References 11 publications

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“…t Exchanges previously reported by Rakowski & Symons (1989). Exchange is shared by two or more clones.…”

Section: The Progression Of Symptom Development After Inoculation Witmentioning

confidence: 99%

“…ASBVd-specific synthetic oligonucleotide primers complementary to residues 161 to 179 or homologous to residues t80 to 198 of ASBVd SB-1 (Symons, 1981) were used. This primer pair covers an ASBVd site which had shown no sequence heterogeneity in the 51 eDNA clones analysed by Rakowski & Symons (1989).…”

Section: Methodsmentioning

confidence: 99%

“…The primers used to generate full-length cDNA clones of the three ASBVd variants were made using the sequences of regions complementary (residues 161 to 179) and homologous (residues 180 to 198) to ASBVd SB-1 (Symons, 1981) in which no nucleotide exchanges have previously been reported (Pallas et al, 1988;Rakowski & Symons, 1989). The three full-length cDNA clones of each ASBVd variant were found to have lengths of between 247 and 250 nucleotides.…”

Section: Nucleotide Sequence Of Asbvd Variantsmentioning

confidence: 99%

“…The existence of ASBVd variants has been inferred from differences in the nucleotide sequence and molecular size estimates of ASBVd isolates (Palukaitis et al, 1981;Spiegel et al, 1984;Pallas et al, 1988;Rakowski & Symons, 1989). However these proposed strains have never been positively characterized as distinct variants by differences in their biological properties.…”

Section: Introductionmentioning

confidence: 99%

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Avocado sunblotch disease: a persistent viroid infection in which variants are associated with differential symptoms

Semancik

Szychowski

1994

Journal of General Virology

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“…t Exchanges previously reported by Rakowski & Symons (1989). Exchange is shared by two or more clones.…”

Section: The Progression Of Symptom Development After Inoculation Witmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Nucleotide Sequence Of Asbvd Variantsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Avocado sunblotch disease: a persistent viroid infection in which variants are associated with differential symptoms

Semancik

Szychowski

1994

Journal of General Virology

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“…This polymorphic population structure arises as a result of (i) the high mutation rates inherent to the cellular DNA-dependent RNA polymerases involved in viroid replication subverted to replicate an RNA template and (ii) the diverse and fluctuating selective pressures imposed by the different host species. Surveys of diversity have been performed for different viroid species, including pospiviroidae such as citrus exocortis viroid (CEVd) (Visvader & Symons, 1985;Gandía et al, 2005Gandía et al, , 2007, citrus dwarfing viroid (formerly citrus viroid III) (Owens et al, 2000), citrus bent leaf viroid (Foissac & Duran-Vila, 2000;Gandía & Duran-Vila, 2004), potato spindle tuber viroid (PSTVd) (Gó ra et al, 1994;Gruner et al, 1995;Gó ra-Sochacka et al, 1997), hop stunt viroid (HSVd) (Kofalvi et al, 1997;Palacio-Bielsa et al, 2004) and grapevine yellow speckle viroid 1 (Rigden & Rezaian, 1993;Polivka et al, 1996), as well as avsunviroidae such as chrysanthemum chlorotic mottle viroid (Navarro & Flores, 1997;Codoñer et al, 2006), peach latent mosaic viroid (Hernández & Flores, 1992;Ambró s et al, 1998Ambró s et al, , 1999 and avocado sunblotch viroid (Rakowski & Symons, 1989).…”

Section: Introductionmentioning

confidence: 99%

Effect of citrus hosts on the generation, maintenance and evolutionary fate of genetic variability of citrus exocortis viroid

Bernad

Duran-Vila

Elena

2009

Journal of General Virology

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Citrus exocortis viroid (CEVd) populations are composed of closely related haplotypes whose frequencies in the population result from the equilibrium between mutation, selection and genetic drift. The genetic diversity of CEVd populations infecting different citrus hosts was studied by comparing populations recovered from infected trifoliate orange and sour orange seedling trees after 10 years of evolution, with the ancestral population maintained for the same period in the original host, Etrog citron. Furthermore, populations isolated from these trifoliate orange and sour orange trees were transmitted back to Etrog citron plants and the evolution of their mutant spectra was studied. The results indicate that (i) the amount and composition of the within-plant genetic diversity generated varies between these two hosts and is markedly different from that which is characteristic of the original Etrog citron host and (ii) the genetic diversity found after transmitting back to Etrog citron is indistinguishable from that which is characteristic of the ancestral Etrog citron population, regardless of the citrus plant from which the evolved populations were isolated. The relationship between the CEVd populations from Etrog citron and trifoliate orange, both sensitive hosts, and those from sour orange, which is a tolerant host, is discussed. INTRODUCTIONViroids are small plant pathogens consisting of a naked single-stranded circular RNA molecule of 246-475 nt, that do not encode any proteins but are endowed with autonomous replication in their host plants. It is very likely that viroids have been co-evolving with their hosts since their origin, although many of them show a wide host range. The identification of viroids in wild and cultivated plants, as symptomless carriers, suggests that certain hosts may act as natural viroid reservoirs (Diener, 1995).Viroids are taxonomically classified into two families, Pospiviroidae and Avsunviroidae (Elena et al., 1991). These families mainly differ in three characteristics. First, all pospiviroidae present a central conserved region (CCR) in their rod-like secondary structure, whereas the avsunviroidae lack such a region. Second, the pospiviroidae rely on cellular factors to process their multimeric replication intermediates into unit-length molecules, while the avsunviroidae present hammerhead ribozyme structures that are able to self-cleave the multimeric forms. Third, the pospiviroidae replicate in the nucleus whereas the avsunviroidae replicate in the chloroplast (reviewed by Flores et al., 2005).Like most RNA and some DNA viruses, viroids replicate within their hosts as polymorphic populations composed of closely related sequence variants generally distributed around a predominant one. This polymorphic population structure arises as a result of (i) the high mutation rates inherent to the cellular DNA-dependent RNA polymerases involved in viroid replication subverted to replicate an RNA template and (ii) the diverse and fluctuating selective pressures imposed by the different ...

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Detection of avocado sunblotch viroid variants using fluorescent single-strand conformation polymorphism analysis

Schnell¹,

Olano²,

Kuhn

2001

Electrophoresis

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A specific reverse transcription-polymerase chain reaction (RT-PCR) protocol has been developed for routine detection of avocado sunblotch viroid (ASBVd). Modifications in this diagnostic technique were made to enable fluorescent detection and variant identification using automated capillary electrophoresis (CE) and fluorescent single-strand conformation polymorphism (SSCP) analysis. Sixteen sequence variants characterized in a previous study were analyzed using CE-SSCP on two ABI 310 Genetic Analyzers. Significant differences were detected between data obtained from the two ABI 310 Genetic Analyzers indicating that an internal control must be run concurrently with the samples. The 16 variants could be classified into 11 groups based on the SSCP patterns. The statistical analysis of the migration rate data provided support for the visual differences in SSCP patterns. The use of SSCP in the ASBVd assay is easily accomplished and gives an estimate of the number of variants in crude samples extracted from infected avocado plants.

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Comparative sequence studies of variants of avocado sunblotch viroid

Cited by 34 publications

References 11 publications

Avocado sunblotch disease: a persistent viroid infection in which variants are associated with differential symptoms

Avocado sunblotch disease: a persistent viroid infection in which variants are associated with differential symptoms

Effect of citrus hosts on the generation, maintenance and evolutionary fate of genetic variability of citrus exocortis viroid

Detection of avocado sunblotch viroid variants using fluorescent single-strand conformation polymorphism analysis

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