From the Abstract: We generated a genome-scale reconstruction of the metabolic network of R. solanacearum, together with a macromolecule network module accounting for the production and secretion of hundreds of virulence determinants. By a combination of constraint-based modeling and metabolic flux analyses, we quantified the metabolic cost for production of virulence factors. We demonstrated that a trade-off between virulence factor production and bacterial proliferation is controlled by the quorum-sensing-dependent regulatory protein PhcA. A phcA mutant is avirulent but has a better growth rate than the wild-type strain. Moreover, a phcA mutant has an expanded metabolic versatility, being able to metabolize 17 substrates more than the wild-type. Model predictions indicate that metabolic pathways are optimally oriented towards proliferation in a phcA mutant and we show that this enhanced metabolic versatility in phcA mutants is to a large extent a consequence of not paying the cost for virulence. This analysis allowed identifying candidate metabolic substrates having a substantial impact on bacterial growth during infection. These findings provide an explanatory basis to the emergence of avirulent variants in R. solanacearum populations in planta or in stressful environments.
** Lab member paper**: “A Resource Allocation Trade-Off between Virulence and Proliferation Drives Metabolic Versatility in the Plant Pathogen Ralstonia solanacearum” is published in Plos Pathogens by Remi Peyraud et al. This is a part of Remi’s work while he was a post-doc in Stephane Genin’s lab that he finished up while in our group.