Sayed Sartaj Sohrab, Muhammad Yasir and Sherif Al-Kafrawy
King Fahd Medical Research Center, King Abdulaziz University, Jeddah, Saudi Arabia
Cucumber (Cucumis sativus) is an important vegetable crop and widely cultivated crop around the world. Yellow mosaic and leaf curl disease significantly limits the production of cucumber. Yellow mosaic disease of cucumber is caused by Tomato yellow leaf curl virus belonging to the genus begomovirus of the family Geminiviridae. In this stu dy, naturally infected cucumber leaf samples were randomly collected during field survey and causal virus was transmitted by whiteflies to healthy cucumber seedlings and identified by PCR using begomovirus specific primers. The full-length viral genome was amplified by rolling circle amplification and associated betasatellites were PCR amplified using universal betasatellites primers. The full-length viral genome (~2.7kb) and betasatellites (~1.4kb) were cloned and sequenced bi-directionally. The complete viral genome sequences had 2784 nucleotides and showed highest (99.6%) similarity with Tomato Yellow leaf curl virus-Jeddah isolate followed by 99.4-93.0% similarity with an isolate of Tomato Yellow leaf curl virus identified from Jizan and Al-Qasim, Saudi Arabia. The newly identified virus from cucumber formed the closest cluster with Tomato yellow leaf curl virus isolates from Jeddah, Jizan and Al Qasim, Saudi Arabia. Currently, there is no any published report available describing begomovirus associated disease of cucumber in Saudi Arabia. On the basis of results obtained from field survey, PCR detection, sequence identity matrix and phylogenetic relationship it is concluded that the virus causing yellow mosaic disease could be a variant of tomato yellow leaf curl virus isolate circulating in the Kingdom. This is the first report about the association of begomovirus causing yellow mosaic disease of cucumber in Saudi Arabia.