Sequence Analysis of Plum pox virus Strain C Isolates from Russia Revealed Prevalence of the D96E Mutation in the Universal Epitope and Interstrain Recombination Events.

Anna Sheveleva,Tatiana Gasanova,Gennady Osipov,Sergei Chirkov,Peter Ivanov

doi:10.3390/v10090450

Abstract

The understanding of genetic diversity, geographic distribution, and antigenic properties of Plum pox virus (PPV) is a prerequisite to improve control of sharka, the most detrimental viral disease of stone fruit crops worldwide. Forty new PPV strain C isolates were detected in sour cherry (Prunus cerasus) from three geographically distant (700–1100 km) regions of European Russia. Analysis of their 3’-terminal genomic sequences showed that nineteen isolates (47.5%) bear the D96E mutation in the universal epitope of the coat protein. Almost all of them cannot be detected by the monoclonal antibody 5B in triple antibody sandwich enzyme-linked immunosorbent assay and Western blot analysis that may potentially compromise serological PPV detection in cherries. Full-length genomes of seven PPV-C isolates were determined employing next-generation sequencing. Using the Recombination Detection Program (RDP4), the recombination event covering the region from (Cter)P1 to the middle of the HcPro gene was predicted in all the available PPV-C complete genomes. The isolates Tat-4, belonging to the strain CV, and RU-17sc (PPV-CR) were inferred as major and minor parents, respectively, suggesting possible pathways of evolution of the cherry-adapted strains. Downy cherry (P. tomentosa) was identified as the natural PPV-C host for the first time.

Highlights

Plum pox virus (PPV, genus Potyvirus, family Potyviridae) is the causal agent of sharka, the most detrimental viral disease of stone fruit crops [1]
Using the Recombination Detection Program (RDP4), the recombination event covering the region from (Cter)P1 to the middle of the HcPro gene was predicted in all the available PPV-C complete genomes
All the isolates were readily detected by DAS-Enzyme-linked immunosorbent assay (ELISA) with the polyclonal antibodies to PPV (Table 2) and Reverse Transcription-Polymerase Chain Reaction (RT-PCR) using the primers P1/P2

Summary

Introduction

Plum pox virus (PPV, genus Potyvirus, family Potyviridae) is the causal agent of sharka, the most detrimental viral disease of stone fruit crops [1]. It has a single stranded positive sense RNA genome about 10 kb in length encoding a 355 kDa polyprotein. Based on differences in complete genome sequences and phylogenetic analysis, ten PPV strains (D, M, C, EA, Rec, W, T, An, CR, CV) are recognized to date [2,4,5]. PPV-C, Viruses 2018, 10, 450; doi:10.3390/v10090450 www.mdpi.com/journal/viruses

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