CIFA “La Mojonera,” 04700 El Ejido, Almeria, Spain
In the autumn of 2000, an outbreak of a disease caused considerable losses in greenhouse cucumber crops in Almeria (Spain). Infected plants showed vein clearing followed by chlorosis in leaves and yellow/green chlorotic spots on fruits. These symptoms as well as the presence of Bemisia tabaci in the crops suggested the possible involvement of Cucumber vein yellowing virus (CVYV), a proposed member of the Potiviridae family, which was first described in 1960 in Cucumis spp. from Israel (1). B. tabaci populations and leaves from cucumber plants were collected from the greenhouses and analyzed by RT-PCR using specific primers (CV(+): 5′-AGCTAGCGCGTATGGGGTGAC-3′; CV(-): 5′-GCGCCGCAAGTGCAA-ATAAAT-3′) that we designed based on the partial sequence published for CVYV (2). Total nucleic acid extracts from both B. tabaci individuals and the collected plants yielded amplification products of the expected size (449 bp), which were cloned and sequenced (Genebank accession number AJ301640). The sequence was 95.6% identical to that previously reported for CVYV. Nonviruliferous B. tabaci whiteflies were given a 24-h acquisition period on symptomatic leaves and then placed in groups of 15 insects on each of 10 healthy cucumber plants at the 4 leaf-stage for a 24-h inoculation period. Inoculated and control plants were analyzed 1 week later and the infection with CVYV was confirmed (10/10) by RT-PCR. Doublestranded RNA extractions from field-collected samples and from plants inoculated under controlled conditions suggested that no dsRNA formation was associated with the infection. This is the first report of CVYV in Spain.
References: (1) S. Cohen and F. E. Nitzany. Phytopathol. Medit. 1:44, 1960. (2) H. Lecoq et al. J. Gen. Virol. 81:2289, 2000.