Serological and Molecular Characterization of Cucurbit chlorotic yellows virus Affecting Cucumber Plants in Egypt

This study was aimed to identify the causal agent inducing virus-like symptoms on cucumber plants for the first report of Cucurbit chlorotic yellows virus (CCYV) in Egypt. A total of 45 symptomatic and asymptomatic cucumber samples were collected from five locations in El-Behira, government, Egypt during June, 2014. Out of 45 samples analyzed by DAS-ELISA, twenty two samples were found infected by CCYV only, two and four samples showed mixed infection with Cucurbit yellow stunting disorder virus+CCYV and Cucurbit aphid-borne yellows virus+CCYV, respectively, whereas the rest of the samples were negative to all three viruses. No RT-PCR products were obtained with all tested samples when the specific primer for Beet pseudo-yellows virus was used. Total RNA was extracted from ELISA positive samples for CCYV and a 353-bp DNA fragment of the HSP70 gene was amplified by RT-PCR using specific primer for CCYV. The synthesized cDNA probe for CCYV was used to confirm the detection of CCYV in singly and mixed infections using dot blot hybridization. The highest similarity (100%) was found with 22 isolates of CCYV isolated from melon, watermelon, cucumber and muskmelon in Japan, China, Taiwan, Lebanon and Sudan was found but the lowest similarity (94.3%) was found with two isolates from cucumber and melon in Iran. To our knowledge, this is the first report of CCYV on cucumber in Egypt.