Isolation and characterization of tobacco necrosis virus detected on some vegetable species

Abstract

A virus disease agent was isolated from greenhouse-grown cucumber (Cucumis sativus L.), field-grown common bean (Phaseolus vulgaris L.) and white cabbage (Brassica oleracea var. capitata (L.) Alef) crops in Lithuania. The diseased vegetable plants expressed various spotting or mottling symptoms on leaves or fruits and necrotic symptoms on older leaves. The objective of this study was to identify the causal agent of the virus-like disease of these plant species. For the identification of the causal virus, the infection from cucumber, common bean and white cabbage leaves or fruits was transmitted to main test plant species which reacted by only local lesions. In electron microscopic preparations from infected plants, only icosahedral virus particles about 26 nm in diameter were detected. According to particle morphology, host range and symptoms, the causal virus was identified as tobacco necrosis virus (TNV). This finding was supported by the reverse transcription–polymerase chain reaction (RT–PCR) technique which confirmed that the virus isolates from the Lithuanian cucumber, common bean and white cabbage crops were identical with the TNV strain A “Nebraska” isolate. Keywords: cabbage, cucumber, bean, tobacco necrosis virus, identification, EM, RT-PCR