Does the Future of Antibiotics Lie in Secondary Metabolites Produced by Xenorhabdus spp.? A Review

Beyond Soil-Dwelling Actinobacteria: Fantastic Antibiotics and Where to Find Them

“…These nematodes, while carrying the bacteria in their gut, infect soil-dwelling insect larvae and once inside release the bacteria into their haemocoel, where they start producing multiple proteins and secondary metabolites that inhibit the insect immune response, supress competitor microorganism growth and allow both bacterial and nematode multiplication, leading to larval death. Just within the genus Xenorhabdus more than 23 secondary metabolite families [ 118 ] have been identified so far and a recent analysis of the BGC distribution in a panel of dozens of strains from the Photorhabdus / Xenorhabdus clade showed that each of them contains between 21 and 41 BCGs, many of them still uncharacterized, highlighting their enormous biosynthetic potential [ 119 ]. For comprehensive overviews of the secondary metabolites produced by these two genera and their bioactivities, please refer to genomic studies and reviews focused on these organisms [ 118 , 119 , 120 , 121 ].…”

“…Just within the genus Xenorhabdus more than 23 secondary metabolite families [ 118 ] have been identified so far and a recent analysis of the BGC distribution in a panel of dozens of strains from the Photorhabdus / Xenorhabdus clade showed that each of them contains between 21 and 41 BCGs, many of them still uncharacterized, highlighting their enormous biosynthetic potential [ 119 ]. For comprehensive overviews of the secondary metabolites produced by these two genera and their bioactivities, please refer to genomic studies and reviews focused on these organisms [ 118 , 119 , 120 , 121 ]. The majority of the BGCs identified so far in these organisms encode NRPS or hybrid NRPS-PKS as well as some RiPPs, so in consequence most of the natural products isolated from these bacteria are peptide or peptide-derived in nature [ 118 , 119 , 120 ].…”

“…For comprehensive overviews of the secondary metabolites produced by these two genera and their bioactivities, please refer to genomic studies and reviews focused on these organisms [ 118 , 119 , 120 , 121 ]. The majority of the BGCs identified so far in these organisms encode NRPS or hybrid NRPS-PKS as well as some RiPPs, so in consequence most of the natural products isolated from these bacteria are peptide or peptide-derived in nature [ 118 , 119 , 120 ]. ( Figure 5 ).…”

Profiling the Production of Antimicrobial Secondary Metabolites by Xenorhabdus khoisanae J194 Under Different Culturing Conditions

“…A few antimicrobial compounds are also insecticidal and antiparasitic (Ji et al, 2004;Crawford et al, 2011;Crawford et al, 2012;Grundmann et al, 2013;Zhou et al, 2013;Fuchs et al, 2014;Kronenwerth et al, 2014;Proschak et al, 2014;Reimer et al, 2014;Zhao et al, 2018;Hacker et al, 2018). Also refer to review by Booysen and Dicks (2020) that focusses on the potential of Xenorhabdus for antibiotic production.…”

“…Xenocin (Singh and Banerjee, 2008) and xenorhabdicin (Thaler et al, 1995) are the only two RPS peptides described to date. For a more extensive review on antimicrobial compound synthesis by Xenorhabdus spp., the reader is referred to Booysen and Dicks (2020). Xenorhabdus peptides are usually synthesized by the non-ribosomal synthetases, hybrid non-ribosomal/polyketide synthetases or ribosomes and can include fatty acid or polyketide chains (Gualtieri et al, 2009;Reimer et al, 2011;Zhou et al, 2013), while non-peptide compounds like benyzlideacetone does not contain any amino groups (Dreyer et al, 2018).…”