The Entner-Doudoroff and Nonoxidative Pentose Phosphate Pathways Bypass Glycolysis and the Oxidative Pentose Phosphate Pathway in Ralstonia solanacearum.

In , a devastating phytopathogen whose metabolism is poorly understood, we observed that the Entner-Doudoroff (ED) pathway and nonoxidative pentose phosphate pathway (non-OxPPP) bypass glycolysis and OxPPP under glucose oxidation. Evidence derived from C stable isotope feeding and genome annotation-based comparative metabolic network analysis supported the observations. Comparative metabolic network analysis derived from the currently available 53 annotated strains, including a recently reported strain (F1C1), representing the four phylotypes, confirmed the lack of key genes coding for phosphofructokinase () and phosphogluconate dehydrogenase () enzymes that are relevant for glycolysis and OxPPP, respectively. F1C1 cells fed with [C]glucose (99% [1-C]glucose or 99% [1,2-C]glucose or 40% [C]glucose) followed by gas chromatography-mass spectrometry (GC-MS)-based labeling analysis of fragments from amino acids, glycerol, and ribose provided clear evidence that rather than glycolysis and the OxPPP, the ED pathway and non-OxPPP are the main routes sustaining metabolism in The C incorporation in the mass ions of alanine ( 260 and 232), valine ( 288 and 260), glycine ( 218), serine ( 390 and 362), histidine ( 440 and 412), tyrosine ( 466 and 438), phenylalanine ( 336 and 308), glycerol ( 377), and ribose ( 160) mapped the pathways supporting the observations. The outcomes help better define the central carbon metabolic network of that can be integrated with C metabolic flux analysis as well as flux balance analysis studies for defining the metabolic phenotypes. Understanding the metabolic versatility of is important, as it regulates the trade-off between virulence and metabolism (1, 2) in a wide range of plant hosts. Due to a lack of clear evidence until this work, several published research papers reported on the potential roles of glycolysis and the oxidative pentose phosphate pathway (OxPPP) in (3, 4). This work provided evidence from C stable isotope feeding and genome annotation-based comparative metabolic network analysis that the Entner-Doudoroff pathway and non-OxPPP bypass glycolysis and OxPPP during the oxidation of glucose, a component of the host xylem pool that serves as a potential carbon source (5). The outcomes help better define the central carbon metabolic network of that can be integrated with C metabolic flux analysis as well as flux balance analysis studies for defining the metabolic phenotypes. The study highlights the need to critically examine phytopathogens whose metabolism is poorly understood.