Innate immune system of the insects plays vital role in safeguarding the host from various non-self molecules, particularly the bacteria. The Entomopathogenic nematodes are symbiotically associated with the bacteria of the family morganallaceae, together facilitate in the host mortality, though the production of toxins. The EPN species of the two genera share common immunosuppression strategies; however, there are dissimilarities in both the mechanism of evasion and interaction of the two nematodes with the insect host immune pathways. The toxins produced by the bacteria cause the host mortality via., cytotoxicity and disrupting the midgut epithelium. Additionally, these toxins also protect the plants from the biotic and abotic stresses. The genetic analysis has pinpointed crucial genes responsible for mediating and regulating the interaction between the nematode-bacterial complex and its various invertebrate hosts. Additionally, the study has revealed novel families of toxins and an inter-kingdom signalling molecule. Notably, phase variation plays a significant role in governing these diverse functions. Various researchers have suggested the cloning of toxinencoding genes from Photorhabdus and Xenorhabdus as a potential strategy for generating transgenic plants.