A metabolic model based on a pangenome core reveals putative conserved biochemical features of the phytopathogen Xylella fastidiosa.

Abstract

Xylella fastidiosa is a xylem-limited phytopathogenic bacterium responsible for severe diseases in many economically important crops. Despite its impact, its metabolism remains poorly characterized due to fastidious growth and the limited availability of defined culture media. Here, we reconstruct the first pangenome-based genome-scale metabolic model for X. fastidiosa, integrating conserved metabolic functions from 18 strains across five subspecies. The resulting consensus model, iXfcore, is manually curated and used to explore the species' metabolic capabilities. Model simulations predict minimal nutritional requirements that guide us in the formulation of defined media to assess biofilm formation in vitro, supporting the utility of the resulting predictions. Network analysis also identifies a previously undescribed model-predicted candidate pathway for acetate assimilation, consistent with genomic evidence but requiring further empirical validation. In addition, the model predicts the overproduction of polyamines, compounds linked to virulence in other phytopathogens. Experimental analyses confirm polyamine production in multiple X. fastidiosa strains in vitro, providing the first evidence of polyamine detection in culture supernatants of this phytopathogen. Overall, iXfcore provides a systems-level framework to investigate X. fastidiosa metabolism, generate testable hypotheses on its physiology and putative virulence-associated traits, and support future strain-specific models and studies of host-pathogen metabolic interactions.