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Okra (Hibiscus esculentus)—A New Host of Turnip mosaic virus in Israel

In July 1999, Hibiscus esculentus plants, grown in garden plots in Galilee, Israel, exhibited chlorosis, vein clearing accompanied by necrosis, and growth reduction. All samples (n = 10) tested positive for Turnip mosaic virus (TuMV) in enzyme-linked immunosorbent assay (ELISA), using a polyclonal antibody produced in our laboratory against purified virus. Virus in crude sap extracted from symptomatic tissue was mechanically transmitted to Chenopodium quinoa, C. amaranticolor, Nicotiana tabacum Xanthi nc and White Burley, N. clevelandii, N. benthamiana, N. sylvestris, and N. rustica, all of which developed symptoms characteristic of TuMV infection (1). ELISA testing of leaf sap extracted from mechanically inoculated indicator plants gave a strong positive reaction to TuMV. Leaf dip preparations of H. esculentus were analyzed by transmission electron microscopy. Filamentous virus particles typical of a potyvirus were observed in samples from symptomatic leaves. General primer pairs, which cover the complete 3′-end of the potyvirus genome were used in a reverse transcription-polymerase chain reaction assay (RT-PCR), gave an expected amplification product of approximately 300 bp. The nucleotide sequence of the PCR product was 97% identical to the CP sequence of other TuMV, thus verifying TuMV infection of H. esculentus. This is the first report of H. esculentus infection by TuMV.

Reference: (1) A. Gera et al. J. Phytopathol. 145:289-293, 1997.