PSTV infection in tobacco (Nicotiana tabacum L.) transformed with PSTV cDNA

Matoušek, J.; Rakouský, S.; Trněná, Ludmila; Riesner, D.

doi:10.1007/bf02921137

Cited by 3 publications

(2 citation statements)

References 8 publications

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“…Thus, minus-strand viroid RNA is apparently more accessible to transgenic antisense or hammerhead ribozyme RNA. Faustmann et al (38) and Matousek et al (39) identified differences in the accumulation of plus-and minus-strand PSTVd. Specifically, there are lower levels of minus-strand intermediates in infected plant cells than circular plus-strand viroid progeny perhaps because (Ϫ) strand intermediaries are either synthesized at lower rate or are degraded much faster than the plus strand monomers.…”

Section: Discussionmentioning

confidence: 99%

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Ribozyme-mediated high resistance against potato spindle tuber viroid in transgenic potatoes

Xicai

Yin

Zhang

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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A hammerhead ribozyme [R(-)] targeting the minus strand RNA of potato spindle tuber viroid (PSTVd) and a mutated nonfunctional ribozyme [mR(-)] were designed, cloned, and transcribed. As predicted, both monomer and dimer transcripts of the active R(-) ribozyme gene could cleave the PSTVd minus strand dimer RNA into three fragments of 77, 338, and 359 bases in vitro at 25 and 50؇C. The tandem dimer genes of R(-) and mR(-) were subcloned separately into the plant expression vector pROK2. Transgenic potato plants (cultivar Desirée) were generated by Agrobacterium tumefaciens-mediated transformation. Twenty-three of 34 independent transgenic plant lines expressing the active ribozyme R(-) resulted in having high levels of resistance to PSTVd, being free of PSTVd accumulation after challenge inoculation with PSTVd, but the remaining lines showed weaker levels of resistance to PSTVd with low levels of PSTVd accumulation. In contrast, 59 of 60 independent transgenic lines expressing the mutated ribozyme mR(-) were susceptible to PSTVd inoculation and had levels of PSTVd accumulation similar to that of the control plants transformed with the empty vector. The resistance against PSTVd replication was stably inherited to the vegetative progenies.

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Section: Discussionmentioning

confidence: 99%

“…This situation may permit the establishment of a more effective ratio of transgenic RNA-to-target (Ϫ) strand intermediates. In addition, the minus-strand RNA may be more accessible to the transgenic RNA transcripts (39).…”

Section: Discussionmentioning

confidence: 99%

Ribozyme-mediated high resistance against potato spindle tuber viroid in transgenic potatoes

Xicai

Yin

Zhang

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

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Instability of potato spindle tuber viroid (PSTVd) cDNA inAgrobacterium tumefaciens

Matoušek¹,

Trněná²,

Rakouský³

et al. 1994

Biol. plant.

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Potato spindle tuber viroid (PSTVd, severe strain) was isolated from tobacco plants transformed with a dimeric infectious expression construct which was maintained for a long time in Agrobacterium tumefaciens. After in vitro hybridization of PSTVd to complete minus transcripts of PSTVd (lethal), the resulting heteroduplexes were analyzed by. electrophoresis under native conditions. Electrophoretic analysis revealed an appearence of electrophoretieally distinguishable heteroduplexes, suggesting an accumulation of mutated sequence variants of PSTVd had occurred in the plant transformants. TGGE analysis of PSTVd eDNA, re-cloned from the original expression vector pCB 1413 to plasmid pUC18 confmned the accumulation of mutations in the eDNA and the instability of this sequence in A. tumefaciens maintained at 4 ~ for 2.5 years. One of these point mutations was identified by sequencing the PSTVd cDNAs isolated from the individual E. coli colonies. This transition (GC-->AT) was localized at the position of 81 in the PSTVd genome, causing the change of C to U in PSTVd plus RNA. Transformation of tobacco with the freshly prepared expression vector containing the dimeric sequence of PSTVd lethal KF440-2 lead to the propagation of PSTVd electrophoretically identical to that derived from the original sequence and maintained in the tomato by a conventional infection.

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Scientific Opinion on the assessment of the risk of solanaceous pospiviroids for the EU territory and the identification and evaluation of risk management options

2011

EFSA Journal

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Following a request from the EU Commission, the EFSA PLH Panel conducted a risk assessment for the EU territory of pospiviroids affecting solanaceous crops, identified and evaluated risk reduction options and evaluated the EU provisional emergency measures targeting Potato spindle tuber viroid (PSTVd). The risk assessment included PSTVd, Citrus exocortis viroid, Columnea latent viroid, Mexican papita viroid, Tomato apical stunt viroid, Tomato chlorotic dwarf viroid, Tomato planta macho viroid, Chrysanthemum stunt viroid and Pepper chat fruit viroid. Four entry pathways were identified, three involving plant propagation material, with moderate probability of entry, and one involving plant products for human consumption, with low probability of entry. The probability of establishment was considered very high. Spread was considered likely within a crop and moderately likely between crop species, with exception of spread to potato, rated as unlikely. The probability of long distance spread within vegetatively propagated crops was estimated as likely/very likely. The direct consequences were expected to be major in potato and tomato, moderate in pepper, minimal/minor in other vegetables and minimal in ornamentals. Main risk assessment uncertainties derive from limited knowledge on pospiviroids other than PSTVd, although all pospiviroids are expected to have similar biological properties. Management options to reduce risk of entry, spread and consequences were identified and evaluated. No management options can prevent establishment. Examples of successful PSTVd eradication are linked to timely and strict implementation of measures. Uncertainty exists on the effectiveness of risk reduction strategies targeting only one pathway. The EU provisional emergency measures appeared to have significantly reduced PSTVd incidence in Solanum jasminoides and Brugmansia sp., even though eradication from the EU is so far incomplete. The low PSTVd incidence in food crops did not permit to conclude whether the reduction in PSTVd prevalence in ornamentals led to a reduction in outbreaks in food crops.

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PSTV infection in tobacco (Nicotiana tabacum L.) transformed with PSTV cDNA

Cited by 3 publications

References 8 publications

Ribozyme-mediated high resistance against potato spindle tuber viroid in transgenic potatoes

Ribozyme-mediated high resistance against potato spindle tuber viroid in transgenic potatoes

Instability of potato spindle tuber viroid (PSTVd) cDNA inAgrobacterium tumefaciens

Scientific Opinion on the assessment of the risk of solanaceous pospiviroids for the EU territory and the identification and evaluation of risk management options

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