Centre of Microbial and Plant Genetics, Katholieke Universiteit Leuven, 3001 Heverlee, Belgium.
Microb Ecol. 2011 Nov;62(4):941-7. doi: 10.1007/s00248-011-9885-9. Epub 2011 Jun 7.
Bacterial lipopeptides (LPs) are a diverse group of secondary metabolites synthesized through one or more non-ribosomal peptide synthetases (NRPSs). In certain genera, such as Pseudomonas and Bacillus, these enzyme systems are often involved in synthesizing biosurfactants or antimicrobial compounds. Several different types of LPs have been reported for non-pathogenic plant-associated Pseudomonas. Focusing on this group of bacteria, we devised and validated a PCR method to detect novel LP-synthesizing NRPS genes by targeting their lipoinitiation and tandem thioesterase domains, thus avoiding amplification of genes for non-LP metabolites, such as the pyoverdine siderophores present in all fluorescent Pseudomonas. This approach enabled detection of as yet unknown NRPS genes in strains producing viscosin, viscosinamide, WLIP, or lokisin. Furthermore, it proved valuable to identify novel candidate LP producers among Pseudomonas rhizosphere isolates. By phylogenetic analysis of these amplicons, several of the corresponding NRPS genes can be tentatively assigned to the viscosin, amphisin, or entolysin biosynthetic groups, while some others may represent novel NRPS systems.
细菌脂肽（LPs）是通过一个或多个非核糖体肽合成酶（NRPSs）合成的一类多样化的次级代谢产物。在某些属中，如假单胞菌和芽孢杆菌，这些酶系统通常参与合成生物表面活性剂或抗菌化合物。已报道了几种不同类型的非致病性植物相关假单胞菌的 LP。我们专注于这群细菌，设计并验证了一种 PCR 方法，通过靶向它们的脂酰化和串联硫酯酶结构域来检测新型 LP 合成 NRPS 基因，从而避免了非 LP 代谢产物基因的扩增，例如所有荧光假单胞菌中存在的铁载体绿脓菌素。这种方法能够检测到产生粘菌素、粘菌素酰胺、WLIP 或 lokisin 的菌株中尚未知的 NRPS 基因。此外，它在鉴定假单胞菌根际分离株中的新型 LP 生产候选物方面也很有价值。通过对这些扩增子的系统发育分析，可以将相应的 NRPS 基因初步分配到粘菌素、amphisin 或 entolysin 生物合成群中，而其他一些可能代表新型 NRPS 系统。
