الفهرس 
Properties of the different Potyvirus proteins.Only 14 pages are availabe for public view
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Abstract
Potato virus Y (PVY) and potato virus X (PVX) represent part of the most
important viruses affecting cultivated potatoes in Egypt. Different potato plants
were collected from an experimental station in Giza Governorate, Egypt and
were tested using RT-PCR. PVY was amplified using primers represented
portion of the coat protein (CP) gene and 3’ untranslated regions (UTR).
Phylogenetic tree showed two main strain groups: Group I regroups PVYN and
PVYNTN stains, while Group II includes PVYO, PVYW and PVYN:O strains. The
Egyptian PVY isolate was clearly classified within group I, and was more
closely related to PVYNTN strains. Ten nucleotide substitutions resulted in 3
conserved amino acid substitutions (V1→I, G7→E, M or V and S8→G) and
were able to differentiate between both groups. The partial coat protein region
was more diverse than that of the 3’UTR (92.6-100% and (97.7-100% identity,
respectively). The 3’UTR of the Egyptian isolate showed RNA secondary
structures different from those of the 5 PVY strains. Regarding the sequence
analysis of PVX, The PVX PCR product of partial CP was not properly
sequenced; seventy sequences correspond to PVX partial CP were retrieved
from GenBank database. Alignment of the 2 GenBank Egyptian PVX sequences
resulted in 11 nucleotide changes; however, they did not result in amino acid
sequence changes. According to the phylogenetic analysis of the nucleotide
sequences, PVX isolates were clustered in 2 groups: Group 1 clustered most
Asian, Australian and North American (USA) isolates. Group 2 clustered the
Egyptian isolates, most European isolates, South American isolates (Canada and
Argentina). The Egyptian isolate (AF191105.1) was closely related to an isolate
from Jordan; however the second Egyptian isolate (AY763582.1) was clustered
with the European isolates. Epitopes prediction of PVY and PVX isolates
resulted in certain conserved epitopes; these epitopes could be synthesized and
used for the production of highly specific antibodies.
Key Words: PVX, PVY, RT-PCR, phylogeny, CP, 3´UTR, strain groups.