Detection of Strains of Potato Virus X and of a Broad Spectrum of Potato Virus Y Isolates by Nucleic Acid Spot Hybridization (NASH). D. C. Baulcombe, Molecular Biologist, Plant Breeding Institute, Maris Lane, Trumpington, Cambridge CB2 2LQ, United Kingdom. E. N. Fernandez-Northcote, Virologist, International Potato Center, Aptdo, 5969, Lima, Peru. Plant Dis. 72:307-309. Accepted for publication 7 September 1987. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0307.

Cloned complementary DNA (cDNA) hybridization probes for potato virus X (PVX) and potato virus Y (PVY) have been evaluated for the detection of PVX and PVY by nucleic acid spot hybridization (NASH). Results with four probes for PVX tested indicated a genomic difference among two Andean and two non-Andean strains. Three of the four PVX probes would be useful for detection of PVX strains. Results with two probes for PVY tested indicated specificity of the probes to the broad spectrum of 27 PVY isolates from the PVY^O, PVY^N, and PVY^C groups of strains obtained from different geographical areas. None of the PVY probes detected genomic differences among the PVY groups of strains. The PVY probes provided conclusive evidence that the other potyviruses tested, namely, potato virus A (PVA), potato virus V (PVV), Peru tomato virus (PTV), wild potato mosaic virus (WPMV), and tobacco etch virus (TEV), are viruses distinct from PVY. The two PVY probes would be useful for detection of PVY strains.