Detection and genetic diversity of Prunus necrotic ringspot virus in the Niagara Fruit Belt, Canada

Abstract

Prunus necrotic ringspot virus (PNRSV) occurs worldwide with stone fruits and roses as its major hosts. To study PNRSV in Canada, a total of 69 samples including 32 from cherry and 37 from peach, were randomly collected from three separate plots in a research farm in the Niagara Fruit Belt, Ontario. Enzyme-linked immunosorbent assay (ELISA) showed that 18 out of 32 cherry trees and 13 out of 37 peach samples were infected by PNRSV with an average incidence of 44.9%. The presence of PNRSV in ELISA-positive samples was confirmed by reverse transcription-polymerase chain reaction (RT-PCR). The near full-length genomic RNA3 segment encoding the 5′-proximal movement protein (MP) and the 3′-proximal coat protein (CP) of the 31 samples was cloned and sequenced. Phylogenetic analysis of MP and CP genes suggest these 31 isolates belong to two groups, PV96 and PV32, with the former as the predominant group. Throughout the 2011 growing season, no obvious phenotypic differences were observed between PNRSV-positive and negative trees. To our best knowledge, this study represents the first characterization of PNRSV in Canada.