Koumoutsi Alexandra, Chen Xiao-Hua, Vater Joachim, Borriss Rainer
Institut für Biologie/Bakteriengenetik, Humboldt Universität Berlin, Chausseestrasse 117, D-10115 Berlin, Germany.
Appl Environ Microbiol. 2007 Nov;73(21):6953-64. doi: 10.1128/AEM.00565-07. Epub 2007 Sep 7.
Environmental strain Bacillus amyloliquefaciens FZB42 differs from the domesticated model organism of the same genus, Bacillus subtilis 168, in its ability to promote plant growth and suppress plant-pathogenic organisms present in the rhizosphere. This behavior is exerted mainly through the production of several nonribosomal cyclic lipopeptides and polyketides, which exhibit a broad range of action against phytopathogenic bacteria, fungi, and nematodes. Here, we provide evidence that the synthesis of the main antifungal agent of B. amyloliquefaciens FZB42, bacillomycin D, is regulated in multiple layers. Expression of the bacillomycin D operon (bmy) is dependent on a single sigma(A)-dependent promoter, P(bmy) and is favored in its natural host by the small regulatory protein DegQ. The global regulators DegU and ComA are required for the full transcriptional activation of bmy. DegU retains a key role since it binds directly to two sites located upstream of the bacillomycin D promoter. Moreover, both DegU and a transmembrane protein of unknown function, YczE, act on a later level of gene expression, exerting their posttranscriptional effects in a hitherto-unknown manner.
环境菌株解淀粉芽孢杆菌FZB42与同一属的驯化模式生物枯草芽孢杆菌168不同，它具有促进植物生长和抑制根际存在的植物病原生物的能力。这种行为主要通过产生几种非核糖体环脂肽和聚酮化合物来实现，这些化合物对植物病原菌、真菌和线虫具有广泛的作用。在此，我们提供证据表明，解淀粉芽孢杆菌FZB42的主要抗真菌剂杆菌霉素D的合成受到多层调控。杆菌霉素D操纵子（bmy）的表达依赖于单个依赖于σ（A）的启动子P（bmy），并且在其天然宿主中受到小调节蛋白DegQ的促进。全局调节因子DegU和ComA是bmy完全转录激活所必需的。DegU起着关键作用，因为它直接结合到杆菌霉素D启动子上游的两个位点。此外，DegU和一种功能未知的跨膜蛋白YczE都在基因表达的后期发挥作用，以一种迄今未知的方式发挥其转录后效应。
