Genome mining for screening and characterization of new lipopeptides with biocontrol applications
Résumé
Cyclic lipopeptides (CLiPs) are secondary metabolites produced by a variety of bacteria. They are nonribosomally synthesized thanks to huge enzymatic complexes working as assembly lines so-called NonRibosomal Peptide Synthetases (NRPS). The mode of synthesis leads to a structural biodiversity as they can contain nonproteinogenic aminoacids as well as D-isomers in the peptidyl moiety. On the other hand, some of them are produced as mixtures of isoforms displaying variable fatty acid chain lengths. For a few decades, CLiPs, especially those produced by PGPR (as Pseudomonas, Bacillus and Burkholderia) have been shown to play key roles in plant protection. Indeed, they can display direct antifungal activities or induce systemic resistance. In this way, CLiP producing microorganisms represent an untapped resource that can be mined for new biocontrol agents identification.
Regarding the modular organisation of the NRPS together with structural features of the CLiPs, specific bioinformatics tools were developed with the aim i) to predict putative production of such compounds from genomic sequencing data, ii) to help in structure characterization by mass spectrometry and iii) to allow dereplication. These tools were used in the framework of the Bioscreen project of INTERREG FWVL SmartBioControl portefolio. Some successful examples will be presented.