エビネ類に発生する黄色斑紋モザイク病の病原，Orchid Fleck Virusについて

Orchid fleck virus(OFV) was isolated from Calanthe spp.(Cal. discolor,Cal. Bicolor,Cal. Hizen,Cal. triplicata,Cal longicalcarata,Cal Satusma) showing light-green and/or yellowish fleck mosaic on the leaves, which different from previously known viruses of Calanthe. OFV caused systemic infection in Calanthe, Chenopodium quinoa and Beta vulgasis var. cicla, and local infection in C.amaranticolor, C. murale, Spinacia oleracea, Tetragonia expansa, Nicotiana tabacum, N. clevelandii, N. glutinasa, N. rustica, Vigna unguiculata. C quinoa and T expansa are useful as indecator hosts and as a source of virus for inoculation, diagnosis and purification. Sap from C. quinoa was infective after dilution to 10-3 but not 10-4, after 10 min at 45 but not 50℃, and after 1 hr at 20℃ but not 2 hrs. For sap inoculation, it is best to use the homogenate of OFV-onfected leaves within about 7-8 min after homogenization in summer and within about 15 min in winter. The virus particles were bullet-shape or bacilliform, approximately 45-50×105-125 nm in a negatively stained praparations. In ultrathin sections, the viroplasms were observed in the nuclei, and the virus particles and the chracteristic spokewheel structures were found both in the nuclei and the cytoplasm. Antiserum (precipitin tiner:1/512) against the present virus reacted strongly with the isolates of OFV-Cy-50, similar to that of homologous virus. In agar gel diffusion tests, no spur formation occurred among Cal. 94-16 and OFV-Cy-50. In SDS-polyacrylamide gel electrophoresis, one major band of Mr 55,000, probably viral nucleocapsid-protein, and three minor proteins were detected, similar to those of OFV･So from Cymbidium.