引起北京豇豆系统坏死和花叶的一个分离物——Ⅰ.寄主范围、提纯和超薄切片

 1981年夏,在京郊大面积受害的豇豆上分离到一株毒原一豇豆分离物。其症状是顶叶系统花叶,褐色坏死和畸形。生物学测定证明其寄主范围广泛,在所测试的6个科19种植物中,能侵染5个科的十余种植物。苋色藜、奎宁藜、千日红、曼陀罗、蚕豆、豇豆为其易感寄主。但不能侵染白菜、油菜、芜菁、黄瓜、菜豆、豌豆、普通烟和心叶烟等植物。该分离物虽在蚕豆上病状与蚕豆萎蔫病毒Stubbs典型株相似,但从其不侵染普通烟和心叶烟似乎又不完全相同。稀释限点:10^-3~10^-4;热灭活点50~55℃;体外保毒期(室温)4天以上。桃蚜或豆蚜传。提纯病毒颗粒呈直径25mm,六角形,其三种组分之沉降常数分别为50S (T),67S (M)和118S (B)。提纯的病毒制品其颗粒极易聚集特别是盐类存在时。电镜观察奎宁藜局部退绿斑的超薄切片发现为蚕豆萎蔫病毒所具有的特征性的横截面由7~9个病毒颗粒所组成的管状结晶物以及由非病毒颗粒所组成的大型晶体内含体。根据上述寄主范围、病状、病毒颗粒形态和组分以及内含体的特征,豇豆分离物是蚕豆萎蔫病毒,很可能是与已知的四种毒株不同的豇豆株。

AN ISOLATE CAUSING SYSTEMIC NECROSIS MOSAIC ON COWPEA IN PEKING SUBURB——Ⅰ.Host range,purification and electron microscopy

We got an cowpea isolate from the cowpea crops naturally severely diseased in large area in Beijing suburb.Infected plants exhibit systemic mosaic and brownish necrosis together with some malformation and distortion of the youngest leaves.The host range of this isolate is quite wide.It infected more than 10 species in 5 families out of 19 species in 6 families tested.Chenopodium amaranticolor,C.quinoa,Gomphrena globosa,Datura stramonium,Viola faba,and Vigna sinensis are rather susceptible while Brassica chinensis,B.rapa,B.oleracea,Cucumber,French bean,Nicotiana tabacum,N.glutinosa are lack of visible symptoms.Although the symptoms of the cowpea isolate on broad bean is very similar to the Stubbs' type Strain of broad bean wilt virus,it seems likely to be a different strain in view of the fact that it can not affect the N.tabacum and N.glutinosa,both of which are very susceptible to the type strain.