From biosynthesis to scavenging: evolutionary rewiring of PUFA and oxylipin biosynthesis in parasitic nematodes.

Polyunsaturated fatty acids (PUFAs) and their oxygenated metabolites (oxylipins) are mediators in regulating membrane function, larval development, and host immune response. In this review, we present that free-living nematodes maintain a relatively complete repertoire of enzymes for PUFA and oxylipin biosynthesis, while parasitic lineages exhibit extensive gene loss and plant-parasitic nematodes show expansion in some enzymes. Meanwhile, parasitic nematodes compensate by scavenging lipids from hosts through the recruitment of various lipid transport proteins. Thus, parasites have lost some enzymes in this metabolic pathway, correlating with host dependence for portions of lipid acquisition, suggesting the plasticity of lipid biosynthesis and acquisition for nematode adaptation to diverse ecological niches.