Abstract
A virus was isolated from large cupped narcissus showing symptoms of mild mosaic collected in Chiba in 1967. The virus was readily transmitted by juice inoculation, but not byMyzus persicae. Among the tested plants of 46 species in 15 families, 36 species of 13 families, namely, Chenopodiaceae, Amaranthaceae, Aizoaceae, Caryophyllaceae, Cruciferae, Leguminosae, Violaceae, Umbelliferae, Solanaceae, Pedaliaceae, Cucurbitaceae, Compositae, and Amaryllidaceae, were found susceptible to the virus. Of these plants,Chenopodium amaranticolor, bean, tobacco (Bright Yellow), petunia and cucumber were considered to be usefull as differential host plants for the virus. The virus was proved to be transmitted also through seeds of soybean at a very high rate.
An evidence of soil transmission was provided by a greenhouse test using soil which surrounded diseased narcissus and was infested with nematodes includingXiphinema americanum. Lots of 1 to 50X. americanum sieved from soil in which infected petunia had been grown for 2 to 3 weeks were placed near the roots of potted healthy petunia and cucumber plants. After 6 weeks the virus was detected, by juice inoculation and serological tests in 6 of 11 petunia plants, and in all of 4 cucumber plants. No infection occurred in control petunia and cucumber plants grown in soil free fromX. americanum.
The virusin vitro withstood heating at 55°C for 10 minutes, but not 65°C, dilution to 2×103, but not 2×104, and 7 days of storage at 20°C, but not 14 days. The virus particles were found to be spherical about 25-30mμ in diameter.
Antiserum prepared showed homologous precipitin tube titre of 1/64. By agar gel diffusion tests, the virus showed negative reaction to antisera to tomato black ring virus and arabis mosaic virus kindly sent from Dr. B.D. Harrison and to tobacco ringspot virus antiserum kindly sent from Dr. R. Stace-Smith. The tomato ringspot antiserum obtained from Dr. R. Stace-Smith only gave positive result. The virus and the antiserum were furthermore sent to Dr. B.D. Harrison, and the above result was confirmed, along with an additional negative result with antiserum to strawberry latent ringspot virus.
From these results, the virus was identified as tomato ringspot virus, which has not been reported before in Japan.
Symptoms caused by this virus in narcissus is not marked. Virus-free narcissus seedlings that were juice inoculated, remained symptomless carriers for 17 months.
