Studies on a Newly Discovered Mosaic Diseaseof Bush Basil (Ocimum basilicum L.) in Taiwan

• Main Author: NerieT.Sanz
• Other Authors: Tsang-Hai Chen
• Format: Others
• Language: en_US
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/34767904055796092599

碩士 === 國立屏東科技大學 === 熱帶農業研究所 === 89 === Abstract An unusual disease occurred in bush basil (Ocimum basilicum L.) fields mainly in Pingtung County and to a lesser extent in Kaohsiung County in southern Taiwan. Foliar symptoms of affected plants included mosaic and leaf distortion. A virus isolate was obtained from the symptomatic basil and subsequently tested for its infectivity on 21 plant species from 5 families by mechanical inoculation. Three species in Chenopodiaceae and one of the plants from Solanaceae were infected. Inoculation of the isolated virus on basil seedling induced symptoms similar to those observed from the fields. Two aphid species, Aphis gossypii Glover and Myzus persicae Sulzer, were found to transmit the virus in a non-persistent manner to healthy basil seedlings. The virus was partially purified. By electron microscopy, isometric virus particles, approximately 30 nm in diameter, were visible. The thermal inactivation point of the virus isolate was 60-70C, dilution end-point was 10-3 to 10-4 and the longevity in vitro of infected sap was 8 days at 24C and more than 10 weeks at -70C. Two protein species with molecular weights of about 42 and 26 kDa were detected after partially purified virus was denatured with sodium dodecyl sulfate (SDS) and analyzed by polyacrylamide gel electrophoresis. The partially purified virus and crude sap from infected Chenopodium quinoa leaves reacted specifically with Broad bean wilt virus (BBWV) antiserum in SDS-agar immunodiffusion test but not with Cucumber mosaic virus (CMV) antiserum. In indirect enzyme linked immunosorbent assay (ELISA), CMV polyclonal antibody did not show correlation with partially purified preparations. The virus was identified as Broad bean wilt virus a member of the Fabavirus genus belonging to the family Comoviridae on the basis of its particle morphology and size, manner of aphid transmission, serology and capsid protein. This was the first report on the natural occurrence of a plant virus of the genus Fabavirus to cause a disease on bush basil in Taiwan.