IDENTIFICATION AND CHARACTERIZATION OF AN AMERICAN PLUM LINE PATTERN VIRUS ISOLATE FROM PALESTINE
N. Alayasa, M. Al Rwahnih, A. Myrta, M.C. Herranz, A. Minafra, D. Boscia, M.A. Castellano, V. Pallás
In a recent survey of the sanitary status of stone fruits in Palestine, a virus (isolate PL27) was transmitted to Nicotiana occidentalis by mechanical inoculation from Japanese plum. Purified virus consisted of quasi-spherical particles 26-35 nm in diameter which sedimented as 3-4 components in density gradient centrifugation. Virus coat protein had an estimated molecular mass of ca. 25 kDa, while four encapsidated RNA bands were visible in electrophoregrams of purified nucleic acid. The nucleotide sequence of a 385 bp PCR-generated amplicon from RNA-3 was determined showing 99% identity at the nucleic acid level and 98.9% similarity at the aminoacid sequence level with a previously characterized RNA-3 region of American plum line pattern virus (APLPV). A digoxigenin-labelled probe was synthesized which specifically recognized virus isolates in extracts from herbaceous and woody samples but did not cross-hybridize with Prunus necrotic ringspot virus (PNRSV), Apple mosaic virus (ApMV), and Prune dwarf virus (PDV). An antiserum to PL27 was raised, which recognized homologous antigens but not PDV and PNRSV. An ELISA kit prepared with this antiserum was successfully used for the detection of PL27 in infected Prunus species. Based on particle morphology, biological, serological, and molecular properties, PL27 was identified as an isolate of APLPV.