Centre Wallon de Biologie Industrielle, Unité de Bioindustries, Gembloux University of Agricultural Sciences, B-5030 Gembloux, Belgium. Centre d'Ingénierie des Protéines, University of Liège, B-4000 Liège, Belgium.
Environ Microbiol Rep. 2009 Apr;1(2):124-30. doi: 10.1111/j.1758-2229.2009.00017.x. Epub 2009 Feb 19.
Cyclic lipopeptides and particularly surfactins produced by Bacillus species retain antibacterial, antiviral, biofilm-forming and plant resistance-inducing activities. In most cases, their role in biological control of plant diseases was evoked on the basis of in vitro assays or by using non-producing/overproducing mutants but there is a need for more direct evidence of an efficient lipopeptide biosynthesis in the rhizosphere. In this work, we coupled LC-MS quantification of the lipopeptides secreted by cells colonizing tomato plants with the use of psrfA-lacZ reporter system integrated within the BGS3 chromosome to study the expression of the surfactin operon in planta. Results showed that a higher level of psrfA induction was observed upon the establishment of a stable BGS3 population on roots and surfactins extracted from the rhizosphere were produced in biologically significant quantities. Our results also demonstrate that BGS3 efficiently utilizes the main substrates from plant exudates to produce surfactins. This synthesis is also efficient in cells forming colonies and the production may be favoured in bacteria developing slowly in the rhizosphere. This provides a first understanding of how environmental factors may influence lipopeptide production by beneficial Bacillus strains.
环状脂肽，特别是芽孢杆菌属产生的表面活性剂，具有抗菌、抗病毒、形成生物膜和诱导植物抗性的活性。在大多数情况下，它们在植物病害生物防治中的作用是基于体外测定或使用非产生/过量产生的突变体来推断的，但需要更多关于在根际有效合成脂肽的直接证据。在这项工作中，我们将细胞定殖番茄植物时分泌的脂肽的 LC-MS 定量与在 BGS3 染色体内整合的 psrfA-lacZ 报告系统的使用相结合，以研究表面活性剂操纵子在植物体内的表达。结果表明，在 BGS3 种群在根上稳定建立时，观察到 psrfA 的诱导水平更高，并且从根际提取的表面活性剂以具有生物学意义的量产生。我们的结果还表明，BGS3 能够有效地利用植物分泌物中的主要底物来生产表面活性剂。这种合成在形成菌落的细胞中也是有效的，并且在根际中生长缓慢的细菌中可能会促进这种生产。这提供了对环境因素如何影响有益芽孢杆菌菌株脂肽产生的初步理解。
