芸薹链格孢致病毒素分析Ⅰ.腐败菌素B的分离提纯和结构鉴定

ANALYSIS OF PATHOGENIC TOXIN FROM ALTERNARIA BRASSICAE Ⅰ.PURIFICATION AND CHEMICAL STRUCTURE IDENTIFICATION OF DESTRUXIN B

芸薹链格孢（Alternariabrassicae）在PD液体培养基中黑暗培养20d，过滤获得培养滤液，经乙酸乙酯萃取、45℃减压浓缩得AB-粗毒素。AB-粗毒素经HPLC分析，在λ＝206nm波长下具有Ⅰ、Ⅱ、Ⅲ和Ⅳ4个明显的吸收峰。组分Ⅲ的红外吸收光谱、FAB／MASS和1H-NMR与已报道的腐败菌素B基本一致，由此确定组分Ⅲ为腐败菌素B。试验发现，芸薹链格孢的培养滤液、AB-粗毒素和毒素组分Ⅲ均能造成白菜叶片黄化、萎蔫和坏死。

Alternaria brassicae was inoculated and cultured in PD liquld medium at 20℃ and in darkcondition for 20d. Crude AB-toxin could be obtained by filtration, ethyl acetate extraction and 45℃ evaporation under vacuum. There were Ⅰ,Ⅰ，Ⅲ and Ⅳ four apparent absorption peaks at λ = 206nm by HPLC analysis. Infra-red absorption spectrum， FAB / MASS and 1H-NMR of AB-toxin Ⅲ were idenhcal to those of Destruxin B. The experimental results also showed that culture filtrate of A. brassicae、 crude AB-toxin and punfied AB-toxin Ⅲ all could induced chlorisis, wilt and necrosis symptom on Chinese cabbage leaves.