Identification of a novel robigovirus and a Prunus -infecting tepovirus in Pyrus communis and their transmissibility on Malu s spp.

High-throughput sequencing (HTS) of three pear trees ( Pyrus communis ) resulted in the identification of two isolates of a Tepovirus species and one isolate of a Robigovirus species, both genera from the family Betaflexiviridae and never reported in pears. Their complete genomes were fully characterized, revealing genomes of about 6.8 kb ( Tepovirus ) and 8.4 kb ( Robigovirus ). According to the species demarcation criteria in the family Betaflexiviridae , the tepovirus isolates reported here are divergent isolates of Prunus Virus T (PrVT). The robigovirus isolate had enough difference in pairwise comparison with its closer related species, cherry virus Turkey (CVTR) and it should be considered a new species of this genus, tentatively named as pomes virus Greece (PVGR). A survey was conducted using specific primers designed for each of the viruses and one additional pear accession tested positive to PrVT. Furthermore, both viruses were successfully graft-transmissible to Malus domestica or Malus micromalus, suggesting their potential to be transmitted to Malus species. This study expands the list of viruses infecting pome fruit trees and augments our knowledge on the molecular diversity and host range evolution of betaflexiviruses.