American Phytopathological Society
April 2004
Interpretive summary

Detection and Confirmation of Potato mop-top virus in Potatoes Produced in the United States and Canada
H. Xu, T.-L. DeHaan, and S. H. De Boer, Canadian Food Inspection Agency, Centre for Animal and Plant Health, 93 Mount Edward Road, Charlottetown, PEI, Canada, C1A 5T1. Plant Dis. D-2004-0120-01R, 2004 (online). Accepted for publication 21 November 2003.

Potato mop-top virus (PMTV, a pomovirus) is a highly destructive and harmful pathogen to potato because it can cause significant tuber quality damage by causing tuber necrosis. This virus was detected in commercial potatoes grown in the United States and Canada by a reverse transcription–polymerase chain reaction (RT-PCR) targeting the coat protein (CP) gene in RNA3. Out of 3,221 lots of seed and ware potatoes that were tested in a survey conducted in 2001 and 2002, 4.3% were positive for PMTV. The reliability of the survey results was confirmed by re-extraction of selected samples and additional RT-PCR tests using two primer sets targeting gene segments in RNA2 and RNA3. PCR products generated from RNA2 and RNA3 were identified by the analysis of fragment length polymorphisms. PMTV was further identified by enzyme-linked immunosorbent assay, bioassay on Nicotiana debneyi, and transmission electron microscopy. Sequence of a portion of the coat protein gene revealed near 100% identity among isolates from the United States and Canada and >97% homology of the North American isolates with European isolates.

Plant Disease is a leading international journal of applied plant pathology, published by The American Phytopathological Society. It publishes original research articles focusing on practical aspects of plant disease diagnosis and control. Each issue also includes a monthly feature article summarizing a significant topic in plant pathology. The Disease Notes section contains timely reports of new diseases, outbreaks, and other pertinent observations. For a full list of contents, visit http://www.apsnet.org/pd/current/.

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