Isolates of citrus exocortis viroid recovered by host and tissue selection

Semancik, J. S.; Szychowski, J. A.; Rakowski, A. G.; Symons, Robert H.

doi:10.1099/0022-1317-74-11-2427

Cited by 69 publications

(54 citation statements)

References 20 publications

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“…The results presented here illustrate how a shift in the composition of the viroid population, owing to host selection, results in major changes in biological properties (infectivity and symptoms) as postulated by Semancik et al (1993).…”

Section: Discussionmentioning

confidence: 94%

“…Other changes identified in Table 2 imply that different hosts p r o d u c e d different selection pressures on the viroid p o p u l a t i o n from in the original b r o a d bean isolate. The sequence of the viroid from t o m a t o revealed a characteristic change in nucleotide 50, also identified in other sequences of C E V d from t o m a t o (Visvader & Symons, 1983Semancik et at., 1993), deletions in nucleotides 163, 217 and 265, and the insertion o f an A residue between residues 129-130. The sequences from chrysa n t h e m u m and c u c u m b e r also contained characteristic changes in nucleotides 6, 316 and 279 (chrysanthemum) and in 6, 147, 316 and 331 (cucumber).…”

Section: Properties Of the Cevd Variant Recovered From Broad Beanmentioning

confidence: 99%

“…2b) has only been found in two unusual isolates recovered from grapevine (Garcia-Arenal et al, 1987) and tomato (Mishra et al, 1991). Changes U~A , A + C and G-+ A at nucleotides 234, 263 and 303, respectively have been reported in several other variants (Visvader et at., 1982;Visvader & Symons, 1983Semancik et al, 1993).…”

Section: Identification Of a C E V D Variant In Broad Beanmentioning

confidence: 99%

“…Moreover, the characterization of most viroids, including CEVd, has been accomplished after their purification from alternative herbaceous hosts which provided high viroid titres (Semancik & Weathers, 1972;Gross et al, 1982;Visvader et al, 1982). Since the viroid population of a given isolate can be modified as a result of host and tissue selection its biological properties may also vary depending on the host chosen for its characterization (Semancik et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

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A citrus exocortis viroid variant from broad bean (Vicia faba L.): infectivity and pathogenesis

Fagoaga

Semancik

Duran-Vila

1995

Journal of General Virology

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A viroid present in very low titres was isolated from symptomless field broad bean plants. It was identified as a variant of citrus exocortis viroid in the T2, V and C domains. Infection of several hosts resulted in a change in the composition of the viroid population. Serial passage through tomato and back to the host of origin, broad bean, resulted in major changes in replication efficiency, host range and pathogenicity. The unique nucleotide sequence differences identified in the original broad bean variant were not conserved after passage through alternative hosts. The effects of these sequence variations on viroid secondary structure result in nonpathogenic viroid variants which can remain unnoticed in certain plant species but may act as reservoirs of viroid disease.

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Section: Discussionmentioning

confidence: 94%

Section: Properties Of the Cevd Variant Recovered From Broad Beanmentioning

confidence: 99%

Section: Identification Of a C E V D Variant In Broad Beanmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A citrus exocortis viroid variant from broad bean (Vicia faba L.): infectivity and pathogenesis

Fagoaga

Semancik

Duran-Vila

1995

Journal of General Virology

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“…The RNA 0001-2628 © 1994 SGM Short communication sequence obtained permitted the synthesis of oligonucleotide primers with sufficient homology or complementarity to synthesize a double-stranded (ds) DNA product from CVd-IIIb RNA with M-MLV reverse transcriptase (RT) and PCR by the method previously described by Semancik et al (1993). From this partial CVd-IIIb sequence, primer C-2 (5' ACTCTACCGTCT-TTACTCCA 3') complementary to the nucleotide 120 to 138 region in the final sequence (Fig.…”

mentioning

confidence: 99%

Nucleotide sequence and structural features of the Group III citrus viroids

Rakowski

Szychowski

Avena

et al. 1994

Journal of General Virology

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The nucleotide sequence and secondary structure of two representative variants from the Group III citrus viroids, CVd-IIIa (297 bases) and CVd-IIIb (294 bases) were determined. The variants are related to the apple scar skin viroid (ASSVd) family. Although smaller in size than any of the ASSVd-related viroids, the central conserved region as well as most of the terminal conserved region of ASSVd is retained. The rod-like structural configuration (characteristic of ASSVd) of the variants as predicted by minimum free energy analysis is presented.

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Viroids

Flores

Daròs

Hernández

et al. 2011

Encyclopedia of Life Sciences

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Viroids are infectious, nonprotein‐coding, highly structured small circular ribonucleic acids (RNAs) able to replicate autonomously and induce diseases in higher plants. Viroids and viruses differ in structure, function and evolutionary origin (with the former regarded as relics of a primitive RNA world). Viroids are classified into the families Pospiviroidae and Avsunviroidae , the members of which replicate in the nucleus and chloroplast, respectively, through an RNA‐based rolling circle mechanism with three steps catalysed by: (i) host deoxyribonucleic acid (DNA)‐dependent RNA polymerases redirected to accept RNA templates, (ii) processing enzymes or, in the family Avsunviroidae , hammerhead ribozymes and (iii) RNA ligases . When infecting a cell, the viroid RNA must travel to its replication organelle, with the resulting progeny moving cell‐to‐cell through plasmodesmata and reaching distal parts through the phloem. Pathogenesis could be triggered by the replicating viroid itself, or via RNA silencing. Viroids are detected by nucleic acid‐based approaches, some can be eliminated from infected plants by meristem tip culturing, and biotechnological approaches are being developed for their control. Key Concepts: Viroids are small nonprotein‐coding RNAs that infect, replicate and induce disease in higher plants. Viroids differ from viruses in fundamental aspects that include structure, function and evolutionary origin. Viroids are classified into the families Pospiviroidae (nuclear viroids) and Avsunviroidae (chloroplastic viroids). Viroid RNAs adopt compact secondary structures additionally stabilised by elements of tertiary structure. Viroids replicate through a rolling circle mechanism with only RNA intermediates and enzyme or ribozyme processing. Different viroids have distinct host ranges and closely related viroids display cross‐protection effects when co‐infecting a common host. Viroids move intracellularly, cell‐to‐cell through plasmodesmata, and long distance through the phloem. Viroids may infect their host plants latently or induce different pathogenic alterations including death. Viroids propagate in their hosts as a population of closely related variants (quasispecies). Viroids are considered molecular fossils of the RNA world postulated to have preceded our present world dominated by DNA and proteins.

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Isolates of citrus exocortis viroid recovered by host and tissue selection

Cited by 69 publications

References 20 publications

A citrus exocortis viroid variant from broad bean (Vicia faba L.): infectivity and pathogenesis

A citrus exocortis viroid variant from broad bean (Vicia faba L.): infectivity and pathogenesis

Nucleotide sequence and structural features of the Group III citrus viroids

Viroids

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