Kang Y, Carlson R, Tharpe W, Schell M A
Department of Microbiology, University of Georgia, Athens, Georgia 30602, USA.
Appl Environ Microbiol. 1998 Oct;64(10):3939-47. doi: 10.1128/AEM.64.10.3939-3947.1998.
Genetic manipulation of fluorescent pseudomonads has provided major insight into their production of antifungal molecules and their role in biological control of plant disease. Burkholderia cepacia also produces antifungal activities, but its biological control activity is much less well characterized, in part due to difficulties in applying genetic tools. Here we report genetic and biochemical characterization of a soil isolate of B. cepacia relating to its production of an unusual antibiotic that is very active against a variety of soil fungi. Purification and preliminary structural analyses suggest that this antibiotic (called AFC-BC11) is a novel lipopeptide associated largely with the cell membrane. Analysis of conditions for optimal production of AFC-BC11 indicated stringent environmental regulation of its synthesis. Furthermore, we show that production of AFC-BC11 is largely responsible for the ability of B. cepacia BC11 to effectively control the damping-off of cotton caused by the fungal pathogen Rhizoctonia solani in a gnotobiotic system. Using Tn5 mutagenesis, we identified, cloned, and characterized a region of the genome of strain BC11 that is required for production of this antifungal metabolite. DNA sequence analysis suggested that this region encodes proteins directly involved in the production of a nonribosomally synthesized lipopeptide.
对荧光假单胞菌的基因操作，为深入了解其抗真菌分子的产生及其在植物病害生物防治中的作用提供了重要线索。洋葱伯克霍尔德菌也具有抗真菌活性，但其生物防治活性的特征描述却少得多，部分原因是应用基因工具存在困难。在此，我们报告了一株洋葱伯克霍尔德菌土壤分离株的遗传和生化特征，该菌株产生一种对多种土壤真菌具有高活性的特殊抗生素。纯化和初步结构分析表明，这种抗生素（称为AFC-BC11）是一种主要与细胞膜相关的新型脂肽。对AFC-BC11最佳产生条件的分析表明，其合成受到严格的环境调控。此外，我们发现AFC-BC11的产生在很大程度上决定了洋葱伯克霍尔德菌BC11在悉生生物系统中有效控制由真菌病原菌立枯丝核菌引起的棉花猝倒病的能力。利用Tn5诱变，我们鉴定、克隆并表征了BC11菌株基因组中产生这种抗真菌代谢物所需的区域。DNA序列分析表明，该区域编码直接参与非核糖体合成脂肽产生的蛋白质。
