Invasive Species Compendium

Detailed coverage of invasive species threatening livelihoods and the environment worldwide

Abstract

First report of Cucumber vein yellowing virus on cucumber in Lebanon.

Abstract

In a 2-year (2008-09) wide-scale survey of viruses infecting cucurbits, a limited number of greenhouse-grown cucumber plants showed vein-yellowing symptoms. Greenhouses were infested with whiteflies (Bemisia tabaci) and infection with Cucumber vein yellowing virus (CVYV) was suspected. Total RNA was extracted from seven plants with vein yellowing symptoms. RT-PCR tests using CVYV-specific primers targeting the coat protein of CVYV gave amplicons of the expected size from seven plants. The sequence of one representative isolate, CVYV-LB3 (GenBank Accession No. JF289167), showed 97, 95.6 and 95.2% pairwise nucleotide identity with isolates from Tunisia (EF538680), Israel (AF233429) and Jordan (JF460793), respectively. In 2012, symptoms resembling CVYV symptoms were not observed in greenhouses in the same areas. In the early spring 2013, a total of 16 leaf samples with vein-yellowing symptoms were collected from the northern coastal areas (Jbeil, Amshit, Tabarja) and 11 samples showing only yellowing on older leaves from the southern coast (Jiyeh). CVYV was detected in all samples from the northern coast and in four samples from the southern coast. Four isolates from the North and two from the South were sequenced (KC990497 to KC990502) and showed high sequence variation. The pairwise nucleotide and amino acid identities between these isolates ranged from 95.1 to 100%, and from 98.5 to 100%, respectively. Pairwise nucleotide and amino acid identities of the isolates with CVYV-LB3 showed variable homology (93.7-98.2% and 94.6-96.6%, respectively). Surveyed plants were also tested for Cucurbit chlorotic yellows virus (CCYV) and Cucurbit yellow stunting disorder virus (CYSDV). Double or triple infection of CCYV and CYSDV occurred in 18 of the 20 CVYV-infected plants. This is thought to be the first report of CVYV on cucurbits in Lebanon and its occurrence in co-infection with CCYV.