Whole Genome Characterization of Prunus Necrotic Ringspot Virus and Prune Dwarf Virus Infecting Stone Fruits in Russia

Abstract

We conducted a survey of the phytosanitary status of the Prunus germplasm collection in the Nikita Botanical Gardens, Yalta, Russia. The virome of plants displaying virus-like symptoms was studied using Illumina MiSeq high-throughput sequencing. Reads related to prunus necrotic ringspot virus (PNRSV), prune dwarf virus (PDV), and ourmia-like virus 1 (OuLV1) were generated in a number of samples. Near complete genomes of two divergent PNRSV isolates, PDV isolate, and a contig partly covered OuLV1 genome were assembled de novo using the metaSPAdes program. The structure of the genomic RNA1, RNA2, and RNA3 of the new ilarvirus isolates was shown to be typical of PNRSV and PDV. This is the first report and characterization of the PNRSV and PDV full-length genomes from Russia, expanding the information on their geographical distribution and genetic diversity. An open reading frames (ORF)-based phylogeny of all full-length PNRSV and PDV genomes available in GenBank divided each ORF into two or three main clusters. A number of isolates migrated from one cluster to another cluster, depending on the analyzed genome segment. The different branching order may indicate reassortment in the evolutionary history of some PDV and PNRSV isolates.