大白菜芜菁花叶病毒的研究

Studies on the Turnip Mosaic Virus of Chinese Cabbage

大白菜花叶病在东北菜区每年都有不同程度的发生,特以秋季干旱年份病害发生加重。经过试验确定大白菜花叶病的主要毒原系芜菁花(?)病毒(TuMV),本文总结1983～1988年的研究结果。经病毒采样纯化和系统的生物学测定。从149个样本中鉴定出136个分离物样本,反应一致,认为大白菜上主要毒原为芜菁花叶病毒(TuMV),约占总样本的91.23％。尚有少数样本分离出为其他毒原(TMV及CMV),将TuMV分离物摩擦接种于普通烟(黄苗榆及白贝菜叶)产生局部枯斑;接种油青菜叶初生明脉后生黄斑块的系统花叶症;接种桂竹香产生碎色花。接种瓜类、马铃薯、番茄、龙葵无症。病毒汁液失毒温度55～60℃;稀释限点1:3000～3500;体外存活期1～4天(亦有(?)天)。病毒粒子线状长度多分布于730nm,病叶经超薄切片电镜观察,在细胞质内有风轮状、环状及带状内含体。提纯病毒A200/280=1.24,与抗TuMV—IgG呈阳性反应。

This research was carried out in Liaoning Province from 1983 up to 1988. About 136 isolates out of 149 specimens with same symptoms have been identified. A representative isolate has been selected and propagated on Brassica pekinensis (Fu San Bao Toa) and identified as Turnip Mosaic Virus (TuMV), which was the main isolate in the whole surveyed speci- mens (91.28%).. Besides, a very small amount of isolates has been iden- tified as CMV and TMV. The isolatc TuMV infected most Nicotiana tabacum plants and showed chlorotic local spots first, enlarged up to 4--5min in diameter, then became brown-rimmed necrotic ring and surrounded by a chlorotic halo,not systemic. The initial symptoms on Chinese cabbage (Brassica pekinensis) were chlorotic mottling and vein-clearing; as systemic infection, after 14--125 days showed mosaic and leaf distortion, and the severe diseased seedlings were stunting. Later on, on the back of the main vein and some branch vein appeared brown necrotic stripes with rough surface. No or veryslight symptom occurs on Nicotiana glutinosa. The stability of virus in cabbage sap was such, that the thermal inactivation point was 55--60,℃, the dilution end Toint: 1: 3000-3500,the infectivity retain at room temperature (20--22℃) for 1--4 or 5 days. The virus particles are filamentous in form, (730nm×13nm). In the ultra-thin sections of the diseased leaves, there are very obvious pin- wheel, belt and ring like bodies in the cytoplasm. The A260/280 from purified virus sap was 1.24. This isolate was really reacted with anti TuMV-IgG. Owing to those properties, it was ensured that this isolate is TuMV, which has moderate pathogenicity,. We suggest that there must be a few different strains in this area, we now call it TuMV In-1. (Another isolate we have got showed local necrotic lesions on Nicotiana glutinosa).