SP1 - Pathogénie microbienne

Plant pathogens and environmental constraints

Recent data show that the regulation of virulence factor production and metabolism are interconnected, and that when infecting animal and plant hosts, pathogenic bacteria tend to use similar factors and mechanisms to control their expression. Furthermore, changing environmental conditions impose adaptation constraints on these pathogens, meaning they must evolve in order to survive. The invited talk will focus on Ralstonia solanacearum, the bacterium that causes a lethal bacterial wilt disease with a very wide host range. The exceptional adaptability of this pathogen is demonstrated by the frequent emergence of strains with enhanced pathogenic properties in agricultural fields, which puts pressure on production. Various studies using evolutionary experiments, functional genomics and transcriptomics demonstrate that master regulators are prime targets for mutations or epimutations during adaptation, inducing global rewiring of virulence and metabolism regulatory pathways. These genomic or epigenomic modifications can induce phenotypic heterogeneity in populations, a crucial adaptive strategy in pathogens to cope with the spatially heterogeneous environments of their host. Integrating the various processes involved in pathogen adaptation is essential for developing rational plant protection strategies. This is a prerequisite for reconciling environmental constraints with food production.