First report of Tomato chlorotic dwarf viroid on Petunia in the United Kingdom
Following the recent findings of Potato spindle tuber viroid (Pospiviroid, PSTVd – EPPO A2 List) in ornamental Solanaceae in Europe, emergency measures were adopted by the European Union (Commission Decision 2007/410/EC*), and EU member states were required to carry out surveys on PSTVd. As part of this survey, 166 samples (asymptomatic) of Petunia were collected from 5 nurseries in Scotland (GB) in 2007. The first screening tests used a general PSTVd probe which also hybridises to other pospiviroid. As a result 13 Petunia varieties tested positive for the presence of a pospiviroid. Further analysis (PCR, sequencing) confirmed the presence of Tomato chlorotic dwarf viroid (Pospiviroid, TCDVd). This was the first time that TCDVd has been detected in the United Kingdom. All infected lots of Petunia were destroyed. Interestingly, in November 2005, 13 accessions of Petunia hybrids from the USA entered the post-entry quarantine station of the Dutch Plant Protection Service. The plants were inspected and tested for quarantine pests. No virus or viroid symptoms were observed but when tested for pospiviroids, the presence of TCDVd was found. This was the first time that TCDVd has been detected on Petunia plants originating from the USA.
Note: TCDVd was first observed in Canada in glasshouse tomatoes (Lycopersicon esculentum cv. ‘Trust’) in Manitoba in 1996. Affected plants showed symptoms resembling those of PSTVd (stunting, distortion, leaf chlorosis). Infected tomato plants had been grown from seeds imported from the Netherlands via the USA. TCDVd was successfully eradicated and not reported since then in Canada. However, TCDVd was recently found in the USA, in 2 tomato glasshouses in Arizona.
* Commission Decision (2007/410/EC) of 12 June 2007 on measures to prevent the introduction into and the spread within the Community of Potato spindle tuber viroid. Official Journal of the European Union L 155, 71-73. http://www.eppo.org/ABOUT_EPPO/EPPO_MEMBERS/phytoreg/eu_texts/2007-410-EC-e.pdf
James T, Mulholland V, Jeffries C, Chard J (2007) First report of Tomato chlorotic dwarf viroid infecting commercial Petunia stocks in the United Kingdom. New Disease Reports Volume 15 (February – July). http://www.bspp.org.uk/ndr/july2007/2007-48.asp
Singh RP, Xianzhou N, Singh M (1999) Tomato chlorotic dwarf viroid: an evolutionary link in the origin of pospiviroids. Journal of General Virology 80(11), 2823-2828 (abst.).
Verhoeven JTJ, Jansen CCC, Werkman AW, Roenhorst JW (2007) First report of Tomato chlorotic dwarf viroid in Petunia hybrida from the United States of America. Plant Disease 91(3), p 324.
INTERNET (last retrieved in 2008-01)
Website of the Ministry of Agriculture and Lands, British Columbia, Canada. Tomato chlorotic dwarf viroid (TCDVd): An overview. http://www.agf.gov.bc.ca/cropprot/tcdvd.htm