First Report and High Prevalence in Noncherry Host of Cherry virus A in Italy.

Cherry virus A (CVA) has been reported to naturally infect sweet and sour cherry, apricot, peach, and plum but has not been associated with any symptoms. In the spring and summer of 2005, samples were collected in Prunus spp. germplasm collections in Campania (Italy) and analyzed by a polyvalent reverse transcription-polymerase chain reaction (RT-PCR) assay (1). Amplicons were sequenced, revealing CVA infection in seven apricot cultivars (Prunus armeniaca L.), one plum (Prunus domestica L.), and one cherry (Prunus avium L.). CVA sequences (GenBank Accession Nos. DQ445275 to DQ445292) compared among themselves and with databank sequences showed pairwise nucleotide sequence identity levels of 80.3 to 99.6% (86.8 to 100% for amino acid sequences), significantly extending the known variability range of CVA. The presence of CVA was confirmed by hybridization with a CVA-specific probe (P39) (2), targeting region different from that amplified in the polymerase chain reaction assay. All samples containing CVA were found to be in mixed infections with Apple chlorotic leaf spot virus (ACLSV) and Apricot pseudo-chlorotic leaf spot virus (plum, apricot), or ACLSV plus Cherry green ring mottle virus (cherry) so that CVA symptomatology could not be evaluated. To our knowledge, these results constitute the first report of the occurrence of CVA in Italy. They confirm the ability of CVA to naturally infect noncherry Prunus spp. hosts with surprisingly high prevalence levels (6 of 14 and 1 of 6 tested apricot and plum cultivars, respectively). References: (1) X. Foissac et al. Phytopathology 95:617, 2005. (2) W. Jelkmann J. Gen. Virol. 76:2015, 1995.