الملخص الإنجليزي
Cucurbits are an important vegetable crops and among them Cucumber (Cucumis sativus) used mainly as vegetables and salad. The cucumber crop was found to exhibit yellow mosaic symptoms grown in the natural field in Saudi Arabia. We collected naturally infected samples and detected the begomovirus infection by polymerase chain reaction and full length as well as betasatellites viral genome was cloned and sequenced. The sequences of the full length viral genome had 2784 and betasatellites had 1377 nucleotides respectively. In a multiple sequences analysis, highest homology was observed with Tomato yellow leaf curl virus previously reported from Jizan and Al-Qasim, Saudi Arabia. The betasatellites sequences were also analyzed but, interestingly the highest homology was observed with Tomato yellow leaf curl betasatellites reported from Jeddah and Oman. In a phylogenetic tree analysis, the closest cluster was formed with begomovirus isolates identified earlier from Jizan and Al-Qasim. Based on the results obtained in this study, it is concluded that a variant of Tomato yellow leaf curl virus associated with yellow mosaic disease of cucumber in Saudi Arabia. These findings provide valuable information about the natural infection and disease spread caused by begomovirus in new geographic regions on new host.
