Two Isolates of Potato Virus Y (PVY) and the Response of Different Potato Cultivars Against the Viral Infection

Potato virus Y (PVY), of the genus Potyvirus, family Potyviridae, is highly pathogenic virus, causing enormous economic losses in solanaceous crops. Based on the ELISA test for the screened areas, the virus incidence ranged from 15- 30%. Mild mosaic and/ or mottling associated with leaf deformation were observed after 21 days on N. tabacum cv (white barley and galtinosa), mechanically inoculated with PVY- Kafer El-Zayat isolate. However, only mild mosaic was observed on same plants following PVY-Komhamada challenge. Molecular analysis measures including, coat protein amplicons, RFLP, sequence and phylogenetic analysis of the viral CP genes (~900 bp), confirmed that the two PVY isolates are existed in Egypt (Borg El Arab and Kafer El Zayat isolates). These two isolates were in close relation to France (KC005883) and Germany (AJ890342) isolates with identity 95% and 90%, respectively. Our results showed that the potato cultivar Spunta was more resistant to the infection by the PVY and the viral coat protein gene exhibited a low level of expression compared to the other two cultivars, Cara and Diamont. Collectively, our study here demonstrates that the two PVY isolates were commonly distributed in the Egyptian potato fields and their origin are European and Spunta potato cultivar is the recommended cultivar for cultivation in all the examined areas