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Etiology

Purification and Properties of Hibiscus Chlorotic Ringspot Virus. H. E. Waterworth, Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Plant Introduction Station, Glenn Dale, MD 20769; R. H. Lawson(2), and R. L. Monroe(3). (2)Research Plant Pathologist, Agricultural Research Service, U.S. Department of Agriculture, Plant Introduction Station, BARC-West, Beltsville, MD 20705; (3)Biological Technician, APHIS, Glenn Dale, MD 20769. Phytopathology 66:570-575. Accepted for publication 15 December 1975. DOI: 10.1094/Phyto-66-570.

A serologically identical virus was isolated from 14 cultivars of Hibiscus rosa-sinensis, some of which showed mosaic or chlorotic rings, or spots of various sizes and intensity on most leaves. The virus was readily isolated when flower petals were triturated in buffer and the homogenate rubbed on Hibiscus cannabinus (kenaf) seedlings. The virus infected 12 of 13 species of the Malvaceae that were tested, but infected only 8 of 54 species representing 21 other families. The only nonmalvaceous genera with susceptible species were Chenopodium, Gomphrena, Phaseolus, Vigna, Antirrhinum, Digitalis, and Torenia. The best local lesion hosts were Chenopodium quinoa and C. amaranticolor, with distinct chlorotic lesions, and kenaf, which produced necrotic lesions. Yields of the single-component virus purified from kenaf averaged 0.35 mg/g of tissue. Virus particles, stained with 2% phosphotungstic acid adjusted to pH 6.8, measured 27-30 nm. An immunized rabbit produced an antiserum with a titer of 1:512. The virus was serologically unrelated to any of 43 other spherical viruses. Sap from diseased kenaf remained infectious for 30 days at 22 C, when heated to 72 C for 10 minutes, or when diluted 1 × 10^–8. Ratio of bases was A = 25.5, C = 26.4, G = 23.8, and U = 24.3. The virus probably is the same as the Hibiscus ringspot virus described in the literature.