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

Fagoaga, Carmen; Semancik, J. S.; Duran-Vila, N.

doi:10.1099/0022-1317-76-9-2271

Cited by 26 publications

(23 citation statements)

References 28 publications

(33 reference statements)

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“…A CEVd variant found to be highly stable in both sweet orange and citron displayed a pattern of host selection when inoculated to gynura and tomato (Semancik et al, 1993) and other herbaceous hosts (Fagoaga et al, 1995). In contrast, the apparent stability of the parental CVd-II clones would suggest that some of the chimeric constructs as well as the site-mutated variants might introduce a less stable molecular conformation.…”

Section: Molecular Properties Of Hsvd-related Citrus Viroidsmentioning

confidence: 99%

Regulation of pathogenicity in hop stunt viroid-related group II citrus viroids.

Reanwarakorn

Semancik²

1998

Journal of General Virology

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Section: Molecular Properties Of Hsvd-related Citrus Viroidsmentioning

confidence: 99%

Regulation of pathogenicity in hop stunt viroid-related group II citrus viroids.

Reanwarakorn

Semancik²

1998

Journal of General Virology

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“…Viroid populations undergo bottlenecks upon transmission to different hosts. In a previous study, a heterogeneous CEVd population infecting a symptomless broad bean plant evolved to a more homogeneous CEVd population after being inoculated through tomato (Fagoaga et al, 1995;Gandía et al, 2007). In the hostviroid systems studied in this work, differences in the genetic diversity were observed between not only host species but also two different trees of the same species.…”

Section: Discussionmentioning

confidence: 98%

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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“…CEVd sequence variants have been reported to cause bunchytop or leaf chlorosis symptoms in tomato under field conditions (Mishra et al 1991;Verhoeven et al 2004) in India and the Netherlands, respectively. In contrast, in several other host plants in nature such as grapevines (García-Arenal et al 1987), vegetable crops such as broad bean (Fagoaga et al 1995), eggplant, turnip and carrot (Fagoaga and Duran-Vila 1996), CEVd has been shown to be carried symptomlessly. Considering that most of these vegetables are annual seed crops, the route of CEVd entry is currently unknown.…”

Section: Introductionmentioning

confidence: 85%

Citrus exocortis viroid transmission through commercially-distributed seeds of Impatiens and Verbena plants

Singh

Dilworth

et al. 2009

Eur J Plant Pathol

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Surveys of Impatiens and Verbena species in local nurseries in Fredericton, Canada and Verbena species in New Delhi, India showed widespread infection of Citrus exocortis viroid (CEVd) in vegetatively-propagated and seed-grown plants. To determine viroid seed transmission, samples of eight varieties of Impatiens and 11 varieties of Verbena were obtained from four commercial sources. All 19 samples collected contained viroid infection irrespective of variety. The presence of viroid in non-germinated seed was 21%, while the transmission rate in seedlings was 66% in Impatiens walleriana in 2006. Following 2 years of seed storage, the respective figures were 6% and 26%. Similarly, in Verbena x hybrida the presence of viroid in seed was 13% in 2006 with a seedtransmission rate in seedlings of 28%, while the respective figures after 2 years of storage were 5% and 45%.

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

Cited by 26 publications

References 28 publications

Regulation of pathogenicity in hop stunt viroid-related group II citrus viroids.

Regulation of pathogenicity in hop stunt viroid-related group II citrus viroids.

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

Citrus exocortis viroid transmission through commercially-distributed seeds of Impatiens and Verbena plants

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