辣椒炭疽病菌毒素

辣椒炭疽病菌(辣椒刺盘孢Colletotrichum capsici)在25—28℃的Czapek-Dox培养液中振荡培养时分泌出毒素,这种毒素能引起辣椒叶片形成坏死斑,类似于病原菌侵染形成的症状。辣椒叶煎汁培养液和Czapek-Dox培养液适于C.capsici的生长和产毒,生长适宜温度和范围分别为25℃和pH6—7,在25—28℃,pH6—7的条件下培养滤液毒性最强;光线和通气条件可促进C.capsici的生长和产毒;培养14天的培养滤液毒性最强。培养滤液经丙酮沉淀及离子交换树脂柱和Sephadex G-50柱层析将毒素纯化。实验结果表明该毒素为多聚糖类物质。生物检测结果表明:培养滤液和C.capsici毒素溶液能抑制辣椒、绿豆、豌豆、豇豆种子胚根生长;并能使辣椒幼苗发生萎蔫,这一作用与辣椒品种抗性有关。

COLLETOTRICHUM CAPSICI TOXIN

When Colletotrichum capsici was cultured in Czapek-Dox liquid medium at 25—28℃ on shaker,the fungus secreted toxin.The toxin induces lesions on host leaves and the symptoms are similar to those caused by C.capsici in the field. Capsicum leaf broth and Czapek-Dox liquid medium are suitable for C.capsici growth and toxin production.The optimum temperature and pH for growth were 25℃ and pH6—7,respectively.The filtrates at 25—28℃ and pH6—7 were highly toxic.Light and aeration could stimulate growth and toxigenicity.The highest toxicity of culture filtrates occurred on the fourteen day after inoculation.Partially purified toxin was obtained from culture filtrates by precipitation with acetone and through ion-exchange resin and sephadex G-50 chromatography.The results indica- ted that the toxin contained polysaccharide.The results of bioassay showed that cu- lture filtrates and toxin solution inhibit the radicle growth of different capsicum varieties,mungbean,pea and cowpea,and also cause capsicum seedlings wilting.