Am. Chachulska et al., TOBACCO VENOUS NECROSIS DETERMINANTS ARE UNLIKELY TO BE LOCATED WITHIN THE 5'-TERMINAL AND 3'-TERMINAL SEQUENCES OF THE POTATO-VIRUS-Y GENOME, Archives of virology, 142(4), 1997, pp. 765-779
Three potato virus Y isolates, representatives of distinct PVY groups,
identified in potato fields in northern Poland were submitted to biol
ogical and molecular analysis. Phenotypically, two isolates, PVYN-Ny a
nd PVYN-Wi, belong to the necrotic strain and the third one (PVYO-LW)
to the common strain. PVYN-Wi, however, did not react with monoclonal
antibodies directed against the necrotic strain isolates which recogni
se PVYN-Ny. To characterise the isolates, coat protein genes were sequ
enced and compared with sequences from databases. The necrotic PVYN-Wi
isolate showed 99% amino acid homology with the common one-PVYO-LW an
d significantly differed from the second necrotic isolate (PVYN-Ny). S
equence based homology matrix and phylogenetic analysis lead to classi
fication of PVYN-Ny into group I, encompassing solely necrotic strain
isolates, whereas PVYN-Wi falls into a phenotypically heterogeneous gr
oup II. The sequence analysis allowed for identification of putative g
roup I-specific epitopes. 3'NTR (non-translated region) sequences were
identical for PVYN-Wi and PVYO-LW. The 5'NTR, P1 gene, coat protein g
ene and 3'NTR sequences of the common (PVYO-LW) and the necrotic (PVYN
-Wi) isolates are 99-100% homologous. This suggests that tobacco veina
l necrosis determinants are located outside the 3' and 5' terminal seq
uences of the PVY genome.