Occurrence of apple rubbery wood virus 1 and apple rubbery wood virus 2 in pear and apple in Campania (southern Italy) and development of degenerate primers for the rapid detection of rubodviruses

Apple rubbery wood virus 1 (ARWV-1) and apple rubbery wood virus 2 (ARWV-2) are two negative-stranded RNA viruses first reported in apple trees and classified as two different species of the genus Rubodvirus. The geographic distribution of these viruses is mostly unknown. In 2021, during a field survey for viruses infecting pome fruit trees in Campania region (southern Italy) ARWV-1 and ARWV-2 were detected in single and double infections in pear and apple trees by RT-PCR and confirmed by sequencing of the amplicons. A degenerated primer pair, targeting a conserved domain in the RNA-dependent RNA polymerase of known rubodviruses, was designed to develop a RT-PCR assay able to diagnose these viruses at genus level. Preliminary results showed that the assay allowed the detection of ARWV-1 and ARWV-2 in single and mixed infection. Here, we report for the first time the natural occurrence of ARWV-1 in pear and the detection of ARWV-1 in apple and ARWV-2 in apple and pear in Italy, respectively.