New face in the row of bioactive compounds and toxin-antitoxin modules: Xenorhabdus nematophila

Mutualistic symbiosis exists in the natural world between the Enterobacteriaceae genus Xenorhabdus and the entomopathogenic nematode genus Steinernema. Despite the fact that the bulk of the relationships are species-specific, a single Xenorhabdus sp. may infect more than one Steinernema sp. During the complex and stressful life cycle inside the gut of insect as well as in soil, Xenorhabdus nematophila produces various bioactive com-pounds. These bioactive compounds are responsible for killing of infected insect larvae. It also ensures the reproduction and proliferation of the bacteria and nematodes. In this review, we have discussed various bioactive compounds produced by Xenorhabdus nematophila, proving it extremely critical for novel antibiotic discovery in the era of current antibiotic resistance crisis. The wide range of bioactive compounds produced by X. nematophila have antibacterial as well as antifungal properties. However, some of the bioactive compounds are effective against insects, nematodes, protozoa, and has anti-cancer potential too. Further, we have also discussed the increased production and gene regulation of several antimicrobial compounds. In the end, we have also discussed the presence of Toxin-Antitoxin (TA) systems and their involvement in adaptation to multiple adverse environments for the bacteria.