Project: Ecological roles of cyclic lipopeptides from plant-beneficial rhizobacteria: a chemical-biology approach to decipher primary functions of secondary metabolites.

2018-01-01 – 2021-12-31

Abstract

Plant roots often carry Bacillus and Pseudomonas bacteria that protect the plant against
pathogens. This beneficial effect (biocontrol) results from secretion of bacterial metabolites.
Those are either antimicrobial or trigger the plant's own defense responses. These
metabolites include cyclic lipopeptides (CLPs), which are biosurfactants composed of a fatty
acid tail linked to a cyclized oligopeptide. CLPs show amazing structural diversity and are
involved in biocontrol thanks to their multifunctionality. However, it remains unclear which
CLPs are produced in planta and how they are involved in bacterial motility, biofilm formation
on roots, pathogen inhibition and host immunity elicitation. In this project, we will use
innovative chemical and biological tools to study in detail the ecological role of these
fascinating molecules. For this purpose, we bring together a multidisciplinary team composed
of chemists and biologists all sharing a common interest in CLPs. The objective is to answer
the following key questions: which CLPs are readily formed on plant roots; how is their
production modulated by pathogenic fungi and other CLP producers; are these CLPs essential
for root colonization; how do plants respond to their perception; why do some CLPs have
antifungal activity and how do CLPs interact with each other. We are also interested in the
evolutionary origin of CLP diversity and we will propose a novel classification based on their
chemical and biological properties.