The PVY isolate-infected pepper plants confirmed by DAS-ELISA and isolated on
Chenopodium amaranticolor L. where gave chlorotic local lesions. Eleven potato cultivars
(Solanum tuberosum) mechanically inoculated with PVY isolate under greenhouse condition
were divided to three categories, resistant (Diamond, Execusa, Hermes and Valor), tolerant
(Sisi, Lady Balfor, Nikola, Ditta and Lady Rosetta), susceptible (Anabel and Spunta) based on
different external symptoms, the severity infection and virus concentration. Expressed protein
was differed in leaves of potato cultivars. Since PVY infection unexpectedly increased in
(Anabel, Sisi, Lady Balfor, Nicola and Execusa) or decrease of total protein in (Hermes and
Spunta). The potato cultivars (healthy and infected) varied in number and density of protein
bands. As well as specific bands with 72% polymorphism, commonly bands were percentage
24%. On the other hand, the unique band appeared only in infected plants of Valor cv. with MW
85 KDa. Total phenols and proline were increased in tolerant and resistant potato cultivars
compared to susceptible cultivars and healthy ones. Scavenging enzymes (SOD, CAT, POX and
PPO) were increased mostly in tolerant and resistant cultivars compared with susceptible
cultivars and healthy ones. The total number of phenol oxidizing isozymes (POX and PPO)
bands in infected plants of eleven cultivars was varied considerably by increasing, decreasing or
no changes comparing with healthy plants. The presence of Ryadg gene has been observed in
Anabel, Diamond, Nicolas, Dita, Execusa, Hermes and Lady Rosetta. The nucleotide sequence
of Ryadg of cultivars Dita, Execusa and Lady Rosetta was aligned with other recommended PVY
strains registered in GenBank. A phylogenetic tree of Ryadg gene based on nucleotide sequence
revealed 93% a moderate degree of similarity to Potato gene Y-1 isolated from Solanum
tuberosum subsp. andigenum