SEROLOGICAL, MOLECULAR AND ULTRASTRUCTURAL STUDIES ON TOBACCO RATTLE VIRUS-INFECTED POTATO PLANTS IN EGYPT

The aims of the present study were to survey, isolate and identify Tobacco rattle virus (TRV) affecting potato plants under the Egyptian conditions. TRV was isolated from naturally infected potato during two successive seasons (2012-2013 and 2013-2014) in five Egyptian governorates. Symptomatic plants were tested by indirect enzyme linked immune sorbent assay (ELISA). The identity of the virus as TRV was confirmed by host range, modes of transmission, serological diagnosis and morphology of virus particles. RT-PCR was used for the molecular detection of TRV using specific primers. Cytopathological effects of TRV on potato plants were studied. The percentages of tuber transmission ranged from 35 to 55% and transmission by the nematode (Paratrichodorus spp.) reached 17.83%. The obtained results indicated that dot-blotting immune binding assay (DBIA) and tissue-blotting immune binding assay (TBIA) tests were useful to confirm the identification of the virus. Examination of dip preparation by electron microscopy (EM) revealed rod-shaped particles with average length 48-114 nm and 180-197 nm, and 22 nm width. EM analysis showed changes in nucleus, phloem tissue, mitochondria, cell wall, and chloroplast. According to the available data, this is the first isolation of TRV from potato plants in Egypt.