Graz University of Technology, Institute of Environmental Biotechnology, Graz, Austria.
Appl Environ Microbiol. 2012 Jul;78(14):4933-41. doi: 10.1128/AEM.00772-12. Epub 2012 May 4.
Bananas are among the most widely consumed foods in the world. In Uganda, the country with the second largest banana production in the world, bananas are the most important staple food. The objective of this study was to analyze banana-associated microorganisms and to select efficient antagonists against fungal pathogens which are responsible for substantial yield losses. We studied the structure and function of microbial communities (endosphere, rhizosphere, and soil) obtained from three different traditional farms in Uganda by cultivation-independent (PCR-SSCP fingerprints of 16S rRNA/ITS genes, pyrosequencing of enterobacterial 16S rRNA gene fragments, quantitative PCR, fluorescence in situ hybridization coupled with confocal laser scanning microscopy, and PCR-based detection of broad-host-range plasmids and sulfonamide resistance genes) and cultivation-dependent methods. The results showed microhabitat-specific microbial communities that were significant across sites and treatments. Furthermore, all microhabitats contained a high number and broad spectrum of indigenous antagonists toward identified fungal pathogens. While bacterial antagonists were found to be enriched in banana plants, fungal antagonists were less abundant and mainly found in soil. The banana stem endosphere was the habitat with the highest bacterial counts (up to 10(9) gene copy numbers g(-1)). Here, enterics were found to be enhanced in abundance and diversity; they provided one-third of the bacteria and were identified by pyrosequencing with 14 genera, including not only potential human (Escherichia, Klebsiella, Salmonella, and Yersinia spp.) and plant (Pectobacterium spp.) pathogens but also disease-suppressive bacteria (Serratia spp.). The dominant role of enterics can be explained by the permanent nature and vegetative propagation of banana and the amendments of human, as well as animal, manure in these traditional cultivations.
香蕉是世界上消费最广泛的食物之一。在乌干达，这个世界上第二大的香蕉生产国，香蕉是最重要的主食。本研究的目的是分析与香蕉相关的微生物，并选择对真菌病原体有拮抗作用的有效物质，这些病原体是造成大量减产的原因。我们通过非培养方法（16S rRNA/ITS 基因的 PCR-SSCP 指纹图谱、肠杆菌 16S rRNA 基因片段的 pyrosequencing、定量 PCR、荧光原位杂交结合共聚焦激光扫描显微镜、以及广谱质粒和磺胺类抗性基因的 PCR 检测）和培养依赖的方法，研究了从乌干达三个不同传统农场获得的微生物群落（内球、根际和土壤）的结构和功能。结果表明，微生境特异性的微生物群落具有显著的跨站点和处理的特征。此外，所有的微生境都含有大量广谱的土著拮抗菌，针对鉴定出的真菌病原体。虽然细菌拮抗剂被发现富集在香蕉植物中，但真菌拮抗剂的丰度较低，主要存在于土壤中。香蕉茎内球是细菌数量最高的栖息地（高达 10(9)基因拷贝数 g(-1)）。在这里，肠杆菌属的丰度和多样性增加；它们提供了三分之一的细菌，通过 pyrosequencing 鉴定出 14 个属，包括不仅潜在的人类（大肠杆菌、克雷伯氏菌、沙门氏菌和耶尔森氏菌属）和植物（果胶杆菌属）病原体，还有具有疾病抑制作用的细菌（沙雷氏菌属）。肠杆菌属的主导作用可以用香蕉的永久性和营养繁殖以及这些传统种植中人类和动物粪便的添加来解释。
