Mechanism of Antagonism of Oomycete Fungi by Bacillus cereu

这项工作的长期目标是阐明 拮抗作用的基础和调控 卵菌真菌和蜡状芽孢杆菌菌株。 一株B。 已经鉴定出蜡状芽孢杆菌可以防止幼苗感染 由多种卵菌纲真菌所控制 预防感染的能力 与一种低分子量的胞外肽有关。 的 拟议研究的目标是纯化 抗真菌肽，确定其结构，开始确定 它对真菌的作用方式，并确定基因 是其生物合成所必需的。 基因分析将涉及 缺乏抗真菌剂转座子突变体的鉴定 活性，并克隆野生型基因， 对变种人的影响 另一种确定 适当的基因序列将是猎枪克隆DNA从 菌株B. cereus转化为E. coli或B. 枯草杆菌，并通过筛选 抗真菌活性 参与的基因的鉴定 抗真菌剂的生产将为 阐明其生物合成的途径和调控。 这项研究的结果将提供重要的基础 有关生物化学机制的信息- 微生物相互作用 这些基本信息可以在 未来，在发展生态无害的方法， 保护植物免受真菌病原体的侵害。

The longterm goal of this work is to elucidate the mechanistic basis and regulation of an antagonistic interaction between Oomycete fungi and a strain of Bacillus cereus. A strain of B. cereus has been identified that prevents infection of seedlings by a variety of Oomycete fungi. The ability to prevent infection is associated with a low molecular weight, extracellular peptide. The objectives of the proposed research are to purify the antifungal peptide, determine its structure, begin to determine its mode of action on the fungus, and to identify the genes required for its biosynthesis. The genetic analysis will involve identification of transposon mutants that lack antifungal activity, and cloning of the wild-type genes that restore activity to the mutants. An alternative approach to identify the appropriate genetic sequence will be to shot-gun clone DNA from the antifungal strain of B. cereus into either E. coli or B. subtilis, and identify the desired recipients by screening for antifungal activity. Identification of the genes involved in production of the antifungal agent will provide the basis for elucidating the pathway and regulation of its biosynthesis. The results of this research will provide important basic information about biochemical mechanisms involved in plant- microbe interactions. This fundamental information may, in the future, be useful in developing ecologically sound methods for protection of plants from fungal pathogens.