芝麻病毒病害研究——Ⅱ.芝麻黄花叶病病原鉴定

Studies on Sesame Virus Diseases Ⅱ.Identification of the Pathogen of Sesame Yellow Mosaic Disease

继对芝麻矮化坏死病源研究之后,又对普遍发生的芝麻黄花叶病害分离物(YMo—I)进行了系统鉴定。该分离物普遍存在于各芝麻主产区,普通年份发病率为1～5％。YMo—I侵染芝麻引起叶片褪绿及黄绿相间花叶。摩擦接种能够侵染4科12种(品种)植物。局部侵染苋色藜、昆诺藜;系统侵染大豆、花生、望江南、克氏烟等。该病毒能够由桃蚜、花生蚜、大豆蚜以非持久性方式进行传播。ELISA检测其病株种子带毒率为0.5％,但尚未发现种生病苗。病毒在组织汁液中存活期3天;钝化温度55～60℃,稀释限点4×10^(-3)。提纯病毒为弯曲线状粒体,大小约为13×730nm。并有极易凝聚的趋势。病组织中诱导大量典型PVY第一亚组的风轮形和卷筒状细胞质内含体和少数多边形结晶核内含体。血清学上该病毒与花生条纹病毒(PStV)、西瓜花叶病毒—2(MMV—2)密切相关,与花生斑驳病毒、大豆花叶病毒弱相关;与芜菁花叶病毒不相关。但它不侵染WMV—2的寄主—黄瓜,并且该病害田间的发生流行与芝麻、花生的间作方式以及PStV在花生田间的流行密切相关。根据上述结果,YMo—I分离株被鉴定为花生条纹病毒的一芝麻分离株。

Following the successful identification of sesame dwarf necrosis disease, this study focused on the identification of sesame yellow mosaic disease which widely spreaded all over the sesame-grown areas in China with general infecting rate of about 5%. The virus (YMo-I) infected sesame (Sesamum indicum) plant inducing symptoms of evenly chlorotic,yellowing mosaic or mottle of leaves with slight plant stunt. YMo-I could infect mechanically 12 plant species or cultivars of 4 families. Its local hosts were Chenopodium amaranticolor,C.quinoa; and its systematic hosts were peanut,soybean, Cassia occi- dentalis and Nicotiana clevelandii. It was transmitted by Myzus persicae, Aphis craccivora and A. glycine nonpersistantly from sesame or peanut to sesame. The longevity of the virus in vitro was 3 days, the dilution end point was 4×10^(-4) and the thermal inactivation point was 55～60℃. The puri- fied virus particles were flexuous filamentous and were 13×730nm in size. The isolate induced typical pinwheel and scroll cytoplasmic inclusions and crystal nuclear inclusions in diseased sesame tissues. YMo-I was closely related to Peanut Stripe Virus,Watermelon Mosaic Virus-2; weakly to Soybean Mo- saic Virus,Peanut Mottle Virus;and not to Turnip Mosaic Virus in serology. The occurrence of this dis- ease in field was correlated with both the cropping pattern between sesame and peanut crops and the epi- demic of PStV in peanut. According to all the results,YMo-I was identifed as a strain of peanut stripe virus. The transmission rate of the virus through seeds from diseased plant was 0.6% by ELISA test. But there were not any diseased seedslings to develop formthe seeds.