LYZ and infection: In our study, several genes associated with cell death/apoptosis, autophagy and lysozymes (for example: ced-1, ced-3, ced-4, atg16.2, lgg-2, ilys-2 and ilys-3) were detected exclusively in symbiont-associated nematodes, suggesting these genes could be important in regulating the levels of symbiont population and reduce the deleterious effects of infections on host fitness as seen in other studies [24, 59–63].