First Report of Petunia vein clearing virus in Israel.

Abstract

Petunia vein clearing virus (PVCV), a possible member of the cauli-movirus group, was detected in several cultivars of vegetatively propagated petunias grown in commercial nurseries in Israel. Symptoms associated with PVCV infection in petunia cv. Chaplin consisted of stunted young shoots, leaf yellowing, and severe vein clearing. Virus incidence within this cultivar was 40 to 60%. Symptoms were most frequently expressed when plants were subjected to temperatures above 20°C and nutrient deficiencies. The virus was transmitted to petunia only by grafting, however, not by aphids or mechanical inoculation. Leaf dip preparations and thin sections of leaf tissue were analyzed by transmission electron microscopy. Spherical virus particles (45 to 50 nm diameter) were observed in samples from symptomatic petunia plants. In immunoelectron microscopy, the virus particles produced a distinct pattern with the specific antiserum against PVCV provided by D. Lesemann (Biologische Bundesanstalt, Braunschweig, Germany). Infection with PVCV also was confirmed by polymerase chain reaction with total nucleic acid extract preparations. Two primer pairs-5'-GAGGTCAGAGCAAGTCAGAGG-3' (nucleotides 4339 to 4359) and 5'-GTAATGATTTGACTTGTTGAG-3' (nucleotides 5055 to 5075)-were designed to flank a 736-bp sequence in the RNA-dependent RNA polymerase gene of the PVCV genome (GenBank Accession no. U95208). A DNA fragment of the predicted size was visualized in agarose gels. Authenticity of the amplified DNA fragment was confirmed by restriction analysis. The virus has been detected in the past in Germany (1) and recently in the United States (2). This is the first report of PVCV in commercial nurseries in Israel.