Background: The purpose of our main researches has been to obtain genetic and functional characterization of WLIP lip peptide and the interesting phenomenon of defensive white-line formation in Pseudomonads. This unique strategy of Pseudomonas could be useful in controlling clinical pathogens.
Methods: A mutagenesis approach combined with draft genomic sequencing (next generation sequencing) as well as in silico analyses was employed. In parallel, WLIP was extracted, purified and subjected to MS and NMR analyses for structural elucidation and confirmation.
Results: Although the structure of WLIP has been known for more than 2 decades, genetic analysis of its biosynthesis was not yet reported. We have characterized the WLIP-synthesizing NRPS system of P. putida RW10S2 and P. fluorescens LMG 5329. Both systems have several features in common, including three NRPSs genes located in two remote genomic regions, an export system and a LuxR-type regulator. In both species, similar phenotypes are associated with WLIP production: antagonism of some other bacteria, solid-surface motility, and biofilm formation. Remarkably, the P. fluorescens system (Wip) shows homology to viscosingroup NRPS systems, while the P. putida system (Wlp) is more related to systems that produce LPs belonging to other groups with structurally quite different CLPs, namely putisolvin and entolysin. This is an interesting case of convergent evolution. Conclusion: We have characterized the WLR in P. putida and P. fluorescence for the first time. This is a remarkable defensive approach used by Pseudomonas species to battle their pathogenic target. Very recent published reports indicated that such reaction could be widespread than it was expected before.