Metabolomic “Dark Matter” Dependent on Peroxisomal β‑Oxidation in <i>Caenorhabditis elegans</i>

Peroxisomal β-oxidation (pβo) is a highly conserved fat metabolism pathway involved in the biosynthesis of diverse signaling molecules in animals and plants. In <i>Caenorhabditis elegans</i>, pβo is required for the biosynthesis of the ascarosides, signaling molecules that control development, lifespan, and behavior in this model organism. Via comparative mass spectrometric analysis of pβo mutants and wildtype, we show that pβo in <i>C. elegans</i> and the satellite model <i>P. pacificus</i> contributes to life stage-specific biosynthesis of several hundred previously unknown metabolites. The pβo-dependent portion of the metabolome is unexpectedly diverse, e.g., intersecting with nucleoside and neurotransmitter metabolism. Cell type-specific restoration of pβo in pβo-defective mutants further revealed that pβo-dependent submetabolomes differ between tissues. These results suggest that interactions of fat, nucleoside, and other primary metabolism pathways can generate structural diversity reminiscent of that arising from combinatorial strategies in microbial natural product biosynthesis