Association of three begomoviruses and a betasatellite with leaf curl disease of basil in Oman

Basil (Ocimum basilicum) is an important medicinal and aromatic plant native to Asia and Africa. Among 30 different species of Ocimum, common basil is the most widely cultivated species in Oman. During a survey in A'Seeb, a wilayat of Muscat, Oman in 2014, disease symptoms such as severe leaf curling, yellowing, and crinkling were observed on basil plants. To confirm the potential association of begomovirus with this disease, symptomatic leaves were collected, nucleic acid was extracted, and rolling circle amplification (RCA) using Phi 29 DNA polymerase was performed. Restriction analysis of the amplified product was conducted and full-length clones of a putative begomovirus and betasatellite were isolated and characterized. Sequence analyses of several clones showed that the basil plants were infected with Tomato yellow leaf curl virus-Oman (TYLCV-OM), Chili leaf curl virus-Oman (ChLCV-OM), and Tomato leaf curl Albatinah virus (ToLCABV). Infected basil plants also harboured Tomato leaf curl betasatellite-Oman (ToLCB-OM), a satellite associated with leaf curl disease of tomato in Oman. All efforts to clone alphasatellites were unsuccessful, indicating that an alphasatellite was not associated with this infection. This is the first report of the association of multiple begomoviruses along with a betasatellite in the leaf curl disease of basil.