3种海藻的粗蛋白对植物病原真菌的抑制作用

以圆弧青霉(Penicillium cyclopium)、绿色木霉(Trichoderma viride)、红色链孢霉(Neurcsporacrassa)、玉米大斑病菌(Helminthosporium turcicum)、稻瘟病菌(Piricularia oryzae)和黄曲霉(Aspergillusflavus)等6种植物病原真菌为供试菌,检测了3种海藻(铁钉菜Ishige okamurae、羊栖菜Sargassum fusiforme、冈村凹顶藻Laurencia okamurai)的粗蛋白对它们的菌丝生长及孢子萌发的影响.实验表明,3种海藻的粗蛋白对6种真菌的菌丝生长及孢子萌发的作用效果不同,其中冈村凹顶藻粗蛋白对红色链孢霉菌丝的生长,羊栖菜粗蛋白对稻瘟病菌孢子的抑制作用最明显,而羊栖菜和铁钉菜粗蛋白对红色链孢霉的菌丝生长,冈村凹顶藻粗蛋白对绿色木霉及黄曲霉的孢子萌发均无抑制效果.3种海藻的粗蛋白能凝集兔血红细胞,表明它们当中含有凝集素.     

Alteichin: an unusual phytotoxin fromAlternaria eichorniae,a fungal pathogen of water hyacinth

Summary The phytopathogenic fungusAlternaria eichorniae attacks water hyacinth, an economically significant aquatic weed. The novel phytotoxin alteichin was isolated from liquid cultures of this fungus and its structure was deduced by X-ray crystallographic analysis. Altheichin is a doubly hydrated form of 4,9-dihydroxy perylene-3,10-quinone. A single step dehydration of alteichin to anhydroalteichin is catalyzed both by acid and by a crude enzyme preparation from water hyacinth.We thank Dr R. N. Strange for the protoplast assay. Funding was provided by BARD 1-31-79, NIH-CA 24487, Bristol Laboratories, the Montana Agricultural Expt. Station, and NSF.     

Release of active oxygen from phytopathogenic bacteria and their regulation

Some phytopathogenic bacteria including Xanthomonas oryzae pv. oryzae (a rice leaf bacterial blight pathogen) and its virulent gene mutant XooM3105, Xanthomonas campestris pv. campestris, Erwinia carotovora subsp. carotovora and so on, could release active oxygen such as O2 and H2O2 by themselves. Ca2+ , NADPH and O2 concentration regulated the response. The response is sensitive to heat and proteinase. These results show that the component releasing active oxygen in the bacterial plant pathogen may involve special protein and enzyme and be secreted to culture liquid. Various components of rice tissue can significantly induce the release of active oxygen in Xan-thomonas oryzae pv. oryzae.     

植物真菌致病基因的研究进展

通过标记突变技术，从真菌中找到79个致病基因。这些基因在侵染结构形成、细胞壁降解、克服和避免寄主的防卫反应、毒素产生、信号传递以及对寄主体内环境应答等方面发挥重要作用。随着技术的不断完善，陆续发现了一些具有其它功能的致病基因。本文介绍了近几年这方面的研究进展。