Detection and Determination of Biological and Phylogenetic Characteristics of Potato Virus Y (PVY) Isolate of Lorestan Province

Viral diseases are among the factors limiting potato production in the world. Potato virus Y (PVY; genus Potyvirus, family Potyviridae) is one of the most important viruses infecting potato production. In order to detect the virus, plants with viral symptoms (135 samples) such as: mosaic, dwarf, wavy leaf margin, chlorotic spots and leaf malformation were collected from potato fields of different regions of Lorestan province. Infected plants extract was mechanically inoculated on indicator plants: Nicotiana glutinosa, N. occidentalis and N. debneyi. Ten days after inoculation, symptoms including local yellowing, vein clearing, mottling and mosaic on N. occidentalis, mottling and local necrotic on N. glutinosa were observed. Total RNA was extracted from positive indicator plants and cDNA synthesized with specific primers related to CP and NIb gene using RT-PCR. DNA fragments with the expected size of 1115 bp were obtained and PVY contamination was confirmed. Phylogenetic analysis showed that the studied isolate in this research had 98.74 to 99.48% genetic similarity with other recorded sequences in NCBI. The nucleotide sequence of PVY Lorestan isolate was aligned and compared with the related 17 isolates from NCBI. Results of phylogenetic analyses showed that PVY isolates were grouped in two clusters where the PVY Lorestan isolate was placed in cluster ΙI with isolates from Germany which had belonged to Wilga strain. The determined nucleotide sequence in this study was implemented in NCBI with Accession No. MT655949. This is the first report of PVY contamination of potato fields in Lorestan province using the molecular tests.