Characterzation of a potexvirus associated with vein-banding

• Main Authors: Huang, Zheng-yu, 黃琤于
• Other Authors: Lu Yao-Tzun
• Format: Others
• Language: zh-TW
• Published: 1997
• Online Access: http://ndltd.ncl.edu.tw/handle/50978529267096556193

碩士 === 國立中興大學 === 植物病理學系 === 85 === Viral-like symptoms were observed on lily plants from imported bulbs. Although inconspicuous, diseased symptoms include vein-banding mosaic on leaves. Mechanical inoculation with extracts prepared from lily leaves bearing vein- banding mosaic induced yellow local lesions on inolculated leaves on Chenopodium quinoa and C. amaranticolor. Mechanical inoculation of the causal agent also induced local lesions on C. murale, Tetragonia expansa,and Nicotiana glutinosa. A systemic invasion inducing mottling and mosaic was observed on N. benthamiana when plants were inoculated with the causal agent. d mosaic was observed on N. benthamiana when plants were inoculated with the causal agent. The causal agent had a thermal-inactivation point between 60。and 70℃ and a dilution endpoint of 10-7. A differential centrifugation followed by gel filtration was employed for purification of the causal agent from infected C. quinoa. Purified preparation revealed presence of viral particles measured 480 to 520 nm. SDS-PAGE analysis of purified particles revealed the presence of a single protein band with est imated relative molecular mass of 19×103 Da. RNA analysis of purified viruses showed a single RNA band of 6.4 kb. Based on the information on host ranges, physical properties, particle morphology, relative molecular masses of viral protein and RNA, the causal agent was tentatively indentified as lily vein- banding mosaic potexvirus. Antisera with ring precipitin titers of about 1/2048 were produced in rabbits when immunized with the purified virus. immunoglobulins were purified from the antisera by precipitation in 12% sodium sulfate. Alkaline phosphatase (AP) and urease were used to prepare enzyme-antibody conjugates. When ELISA plates were coated with 1 ug/ml or 0.5 ug/ml antibody concentrations, the AP-conjugate prepared by two step method was about twice as sensitive as those prepared by one step method ; the former could be used at 8,000 to 16,000 dilution , whereas the latter at 4,000 to 8,000 dilution . At 0.1 ug/ml or 0.05 ug/ml coating antibody concentrations both conjugates could be used at only 1: 2,000 dilutions. At 1 ug/ml coating antibody concentration , ELISA tests showed that the urease-antibody conjugate prepared by one step method was about 16 times as sensitive as that prepared by two step method; the former could be diluted 16,000 times whereas the latter 1,000 times. When both AP-(by two step method) and urease-(by one step method) conjugates were used at 8,000 dilutions, ELISA tests showed a visible dilution endpoint of 10-5 viral titer in tissue extracts of infected leaves . Test of lily samples by using urease-antibody conjugate showed that 18.6% of Marco polo , 7.7% of Casa-blanca , 25% of Lereve , 20% of Pesaro and 38.9% of Dren land were infected with lily vein-banding mosaic virus.