|David, N -|
|Mallik, I -|
|Gudmestad, N -|
Submitted to: Plant Disease
Publication Type: Research Notes
Publication Acceptance Date: August 5, 2010
Publication Date: October 15, 2010
Citation: David, N., Mallik, I., Crosslin, J., Gudmestad, N.C. 2010. First report of potato mop top virus on potatoes in North Dakota. Plant Disease. 94:1506. Technical Abstract: Potato mop-top virus (PMTV) is the type member of genus Pomovirus. PMTV is an important pathogen of potato, causing serious economic losses in Northern Europe, North and South America, and Asia. PMTV in the United States was first reported in Maine (2). PMTV is vectored by plasmodiophoromycete Spongospora subterranea cv. subterrranea causing powdery scab in potatoes (1). S. subterranea and PMTV are usually associated with cool and humid environments. In spring of 2010, several potato tubers of cv. Russet Burbank were received from Grand Forks County in North Dakota. The tubers had internal multiple concentric necrotic arcs and circles. The presence of PMTV in the necrotic lesions was verified by a positive enzyme-linked immunosorbent assay (DAS-ELISA; Agden Ltd., Scotland Total RNA was extracted from six different tuber lesions that had tested positive with ELISA using a Total RNA isolation kit (Promega Corp. Madison, WI). These extracts were tested for PMTV by reverse transcription (RT)-PCR using two different sets of primers. The primer set C189/H360 ampifies a portion of the capsid protein of PMTV and is expected to yield an amplicon of about 460 bp upon RT-PCR (3). The amplicons generated from the necrotic lesions were cloned (TOPO Cloning; Invitrogen, Carlsbad, CA) and sequenced. Another set of primers, pmtF4/pmtR4 designed to amplify a region in RNA 2 of PMTV, yielded a 417 bp amplicon which also was cloned and sequenced (3). The sequences from all the six tuber lesions were identical to each other for the respective primer sets. A consensus sequence for each primer pair was submitted to GenBank (submitted). The sequences obtained from C189/H360 and pmtF4/pmtR4 amplicons were found to be 99-100% identical to the corresponding regions of the PMTV isolates from Northern Europe (eg. GenBank accessions AJ277556, AM503629 and AY187010). Freeze dried necrotic tuber tissue was sent to an USDA laboratory in WA. The cloning and sequencing at this laboratory confirmed the presence of PMTV infection in the symptomatic tubers. None of the symptomatic tubers tested positive for Tobacco rattle virus, Tomato spot wilted virus, Alfalfa mosaic virus, Potato leaf roll virus, or the necrotic strains of Potato virus Y by RT-PCR. To our knowledge this is the first report of PMTV in North Dakota.