Differentiation and molecular detection of Canadian necrotic strains of Potato virus Y

Abstract

Isolates of Potato virus Y (PVY) from potatoes grown in Canada were identified as tuber necrotic strains on the basis of biological, serological, and molecular characteristics. Only one isolate, however, caused symptoms of potato tuber necrotic ringspot disease (PTNRD) in progeny tubers of inoculated potato plants Solanum tuberosum 'Nadine' under greenhouse conditions. None of the isolates caused symptoms of PTNRD in potato plants 'Russet Burbank' or 'Saco'. A primer set based on the NIb gene for detection of PVY^O by RT-PCR was modified to include detection of the Canadian necrotic isolates of PVY. Restriction analysis of amplicons generated from suspected PVY^NTN isolates with primers based on the P1 protein gene differentiated two sets of isolates. Subsequent comparison of the P1 gene sequence of the Canadian isolates with published sequences confirmed that the isolates corresponded to North American and European types of PVY^NTN. A new primer pair, based on the NIb gene sequence amplified by RT-PCR, allowed the amplification by RT-PCR of a gene fragment from all PVY^N and PVY^NTN isolates but not from PVY^O strains. These primers proved to be useful for detecting the virus in composite samples of potato leaves, sprouts, and tubers.

Keywords:

• Potato virus Y
• necrotic stains
• molecular detection
• differentiation