Metabolic flux pattern of glucose utilization by Xanthomonas campestris pv. campestris: prevalent role of the Entner–Doudoroff pathway and minor fluxes through the pentose phosphate pathway and glycolysis†
The well-studied plant pathogenic bacterium Xanthomonas campestris pv. campestris (Xcc) synthesizes the biotechnologically important polysaccharide xanthan gum, which is also regarded as a virulence factor in plant interactions. In Xcc, sugars like glucose are utilized as a source to generate energy and biomass for growth and pathogenicity. In this study, we used [1-13C]glucose as a tracer to analyze the fluxes in the central metabolism of the bacterium growing in a minimal medium. 13C-Metabolic flux analysis based on gas chromatography-mass spectrometry (GC-MS) confirmed the prevalent catabolic role of the Entner–Doudoroff pathway. Comparative nuclear magnetic resonance (NMR)-based isotopologue profiling of a mutant deficient in glycolysis gave evidence for a moderate flux via glycolysis in the wild-type. In addition to reconfirming the Entner–Doudoroff pathway as a catabolic main route, this approach affirmed a numerically minor but important flux via the pentose phosphate pathway.