Rosner, A., Department of Virology, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel
Maslenin, L., Department of Virology, Agricultural Research Organization, Volcani Center, Bet Dagan 50250, Israel

PVY(NTN) was distinguished from PVY(N) on the basis of differences in electrophoretic mobility of their corresponding RNA transcripts. Transcripts were copied from polymerase chain reaction products of two PVY strains to which the T7 promoter was added. Single-strand and double-strand transcript heteroduplexes of the NTN and N strains exhibited different rate of migration in gel which enabled strain differentiation. This procedure obviates the need for prior information on sequence divergence (e.g. restriction sites, etc.) among the virus isolates.