Identification of nepoviruses in tomato (Lycopersicon esculentum Mill.)

A few nepoviruses (Arabis mosaic nepovirus, Tobacco ringspot nepovirus and Tomato ringspot nepovirus) have already been detected and identified in ornamental plants in Lithuania. The current paper presents the data on identification of two nepoviruses - Tobacco ringspot nepovirus (TRSV) and Tomato black ring nepovirus (TBRV) in tomatoes. Infected tomato plants were assayed by double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA) tests. Extracts of plants that showed positive reaction in DAS-ELISA were inoculated to more than twenty different test-plants. Local lesions and systemic infection were observed in plants belonging to Amaranthus, Nicotiana, Chenopodium, Datura, Gomphrena and Tetragonia genera. Transmission electron microscopy (EM) of extracts from leaves of infected test-plants revealed presence of icosahedral virus particles of similar to 30 nm in diameter that are characteristic of nepoviruses. Presence of TRSV and TBRV in infected test-plants was also detected by reverse transcription-polymerase chain reaction (RT-PCR) using virus-specific primers. Thus, detection and identification of TRSV and TBRV in naturally infected tomatoes and test-plants was confirmed by DAS-ELISA. EM and RT-PCR.