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Dey R, Valle DO, Chakraborty A, Mayer KA, Uppala JK, Chakraborty A, Mirza S, Skwor T, Forst S, Dey M. Quorum sensing regulators and non-ribosomal peptide synthetases govern antibacterial secretions in Xenorhabdus szentirmaii. Front Microbiol 2025; 16:1560663. [PMID: 40143860 PMCID: PMC11936946 DOI: 10.3389/fmicb.2025.1560663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2025] [Accepted: 02/10/2025] [Indexed: 03/28/2025] Open
Abstract
The decades-long gap in antibiotic discovery has led to a significant health crisis due to antimicrobial resistance (AMR). The bacterial genus Xenorhabdus, which forms symbiotic relationships with the soil nematode Steinernema, are known to secrete a variety of antimicrobial compounds with potential effectiveness against AMR. These antimicrobial compounds are primarily bio-synthesized by non-ribosomal peptide synthetases (NRPS) and polyketide synthase (PKS) genes. In this study, we report that X. szentirmaii produces high levels of antibiotic activity during the stationary phase against diverse bacteria including known antibiotic resistant pathogens. It possesses 17 operons to encode predicted NRPS and PKS enzymes, designated as ste1 through ste17. The ste15-ste16 and ste17 operons are predicted to produce the known antibiotics Pax peptide and Fabclavine, respectively. Additionally, the newly identified operons ste3, ste4, ste5, ste8, ste9, and ste14 consist of single genes, each containing two or more NRPS genes. The ste13 operon harbors two NRPS genes, while the ste7 and ste12 operons contain three NRPS genes each. Further, RNA-seq analysis showed that lsrF that encodes a quorum sensing autoinducer-2 (AI-2) thiolase was expressed at high levels during stationary phase. These findings provide evidence that X. szentirmaii uses quorum sensing (QS) to synchronize the expression of multiple NRPS and PKS enzymes responsible for synthesizing various antimicrobial compounds. This study underscores the potential to leverage these regulatory insights for maximizing commercial applications of novel antibiotics combating AMR, as well as broader industrial uses.
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Affiliation(s)
- Ritisha Dey
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Domonique Olivia Valle
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Abhijit Chakraborty
- Center for Cancer Immunotherapy, La Jolla Institute for Immunology, La Jolla, CA, United States
| | - Kimberly A. Mayer
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Jagadeesh Kumar Uppala
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Anish Chakraborty
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Shama Mirza
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Troy Skwor
- Department of Biomedical Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Steven Forst
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
| | - Madhusudan Dey
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI, United States
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Zwyssig M, Spescha A, Patt T, Belosevic A, Machado RAR, Regaiolo A, Keel C, Maurhofer M. Entomopathogenic pseudomonads can share an insect host with entomopathogenic nematodes and their mutualistic bacteria. THE ISME JOURNAL 2024; 18:wrae028. [PMID: 38381653 PMCID: PMC10945363 DOI: 10.1093/ismejo/wrae028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 02/01/2024] [Accepted: 02/15/2024] [Indexed: 02/23/2024]
Abstract
A promising strategy to overcome limitations in biological control of insect pests is the combined application of entomopathogenic pseudomonads (EPPs) and nematodes (EPNs) associated with mutualistic bacteria (NABs). Yet, little is known about interspecies interactions such as competition, coexistence, or even cooperation between these entomopathogens when they infect the same insect host. We investigated the dynamics of bacteria-bacteria interactions between the EPP Pseudomonas protegens CHA0 and the NAB Xenorhabdus bovienii SM5 isolated from the EPN Steinernema feltiae RS5. Bacterial populations were assessed over time in experimental systems of increasing complexity. In vitro, SM5 was outcompeted when CHA0 reached a certain cell density, resulting in the collapse of the SM5 population. In contrast, both bacteria were able to coexist upon haemolymph-injection into Galleria mellonella larvae, as found for three further EPP-NAB combinations. Finally, both bacteria were administered by natural infection routes i.e. orally for CHA0 and nematode-vectored for SM5 resulting in the addition of RS5 to the system. This did not alter bacterial coexistence nor did the presence of the EPP affect nematode reproductive success or progeny virulence. CHA0 benefited from RS5, probably by exploiting access routes formed by the nematodes penetrating the larval gut epithelium. Our results indicate that EPPs are able to share an insect host with EPNs and their mutualistic bacteria without major negative effects on the reproduction of any of the three entomopathogens or the fitness of the nematodes. This suggests that their combination is a promising strategy for biological insect pest control.
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Affiliation(s)
- Maria Zwyssig
- Plant Pathology, Institute of Integrative Biology, Swiss Federal Institute of Technology (ETH) Zurich, CH-8092 Zurich, Switzerland
| | - Anna Spescha
- Plant Pathology, Institute of Integrative Biology, Swiss Federal Institute of Technology (ETH) Zurich, CH-8092 Zurich, Switzerland
| | - Tabea Patt
- Plant Pathology, Institute of Integrative Biology, Swiss Federal Institute of Technology (ETH) Zurich, CH-8092 Zurich, Switzerland
| | - Adrian Belosevic
- Plant Pathology, Institute of Integrative Biology, Swiss Federal Institute of Technology (ETH) Zurich, CH-8092 Zurich, Switzerland
| | - Ricardo A R Machado
- Experimental Biology Research Group, Institute of Biology, University of Neuchatel, CH-2000 Neuchatel, Switzerland
| | - Alice Regaiolo
- Johannes-Gutenberg-University Mainz, Institute of Molecular Physiology, Microbiology and Biotechnology, 55128 Mainz, Germany
| | - Christoph Keel
- Department of Fundamental Microbiology, University of Lausanne, CH-1015 Lausanne, Switzerland
| | - Monika Maurhofer
- Plant Pathology, Institute of Integrative Biology, Swiss Federal Institute of Technology (ETH) Zurich, CH-8092 Zurich, Switzerland
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Mollah MMI, Kim Y. Virulent secondary metabolites of entomopathogenic bacteria genera, Xenorhabdus and Photorhabdus, inhibit phospholipase A 2 to suppress host insect immunity. BMC Microbiol 2020; 20:359. [PMID: 33228536 PMCID: PMC7684946 DOI: 10.1186/s12866-020-02042-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Accepted: 11/10/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Xenorhabdus and Photorhabdus are entomopathogenic bacteria that cause septicemia and toxemia in insects. They produce secondary metabolites to induce host immunosuppression. Their metabolite compositions vary among bacterial species. Little is known about the relationship between metabolite compositions and the bacterial pathogenicity. The objective of this study was to compare pathogenicity and production of secondary metabolites of 14 bacterial isolates (species or strains) of Xenorhabdus and Photorhabdus. RESULTS All bacterial isolates exhibited insecticidal activities after hemocoelic injection to Spodoptera exigua (a lepidopteran insect) larvae, with median lethal doses ranging from 168.8 to 641.3 CFU per larva. Bacterial infection also led to immunosuppression by inhibiting eicosanoid biosynthesis. Bacterial culture broth was fractionated into four different organic extracts. All four organic extracts of each bacterial species exhibited insecticidal activities and resulted in immunosuppression. These organic extracts were subjected to GC-MS analysis which predicted 182 compounds, showing differential compositions for 14 bacteria isolates. There were positive correlations between total number of secondary metabolites produced by each bacterial culture broth and its bacterial pathogenicity based on immunosuppression and insecticidal activity. From these correlation results, 70 virulent compounds were selected from secondary metabolites of high virulent bacterial isolates by deducting those of low virulent bacterial isolates. These selected virulent compounds exhibited significant immunosuppressive activities by inhibiting eicosanoid biosynthesis. They also exhibited relatively high insecticidal activities. CONCLUSION Virulence variation between Xenorhabdus and Photorhabdus is determined by their different compositions of secondary metabolites, of which PLA2 inhibitors play a crucial role.
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Affiliation(s)
- Md Mahi Imam Mollah
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, 36729, South Korea
| | - Yonggyun Kim
- Department of Plant Medicals, College of Life Sciences, Andong National University, Andong, 36729, South Korea.
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Thappeta KRV, Ciezki K, Morales-Soto N, Wesener S, Goodrich-Blair H, Stock SP, Forst S. R-type bacteriocins of Xenorhabdus bovienii determine the outcome of interspecies competition in a natural host environment. MICROBIOLOGY-SGM 2020; 166:1074-1087. [PMID: 33064635 DOI: 10.1099/mic.0.000981] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Xenorhabdus species are bacterial symbionts of Steinernema nematodes and pathogens of susceptible insects. Different species of Steinernema nematodes carrying specific species of Xenorhabdus can invade the same insect, thereby setting up competition for nutrients within the insect environment. While Xenorhabdus species produce both diverse antibiotic compounds and prophage-derived R-type bacteriocins (xenorhabdicins), the functions of these molecules during competition in a host are not well understood. Xenorhabdus bovienii (Xb-Sj), the symbiont of Steinernema jollieti, possesses a remnant P2-like phage tail cluster, xbp1, that encodes genes for xenorhabdicin production. We show that inactivation of either tail sheath (xbpS1) or tail fibre (xbpH1) genes eliminated xenorhabdicin production. Preparations of Xb-Sj xenorhabdicin displayed a narrow spectrum of activity towards other Xenorhabdus and Photorhabdus species. One species, Xenorhabdus szentirmaii (Xsz-Sr), was highly sensitive to Xb-Sj xenorhabdicin but did not produce xenorhabdicin that was active against Xb-Sj. Instead, Xsz-Sr produced high-level antibiotic activity against Xb-Sj when grown in complex medium and lower levels when grown in defined medium (Grace's medium). Conversely, Xb-Sj did not produce detectable levels of antibiotic activity against Xsz-Sr. To study the relative contributions of Xb-Sj xenorhabdicin and Xsz-Sr antibiotics in interspecies competition in which the respective Xenorhabdus species produce antagonistic activities against each other, we co-inoculated cultures with both Xenorhabdus species. In both types of media Xsz-Sr outcompeted Xb-Sj, suggesting that antibiotics produced by Xsz-Sr determined the outcome of the competition. In contrast, Xb-Sj outcompeted Xsz-Sr in competitions performed by co-injection in the insect Manduca sexta, while in competition with the xenorhabdicin-deficient strain (Xb-Sj:S1), Xsz-Sr was dominant. Thus, xenorhabdicin was required for Xb-Sj to outcompete Xsz-Sr in a natural host environment. These results highlight the importance of studying the role of antagonistic compounds under natural biological conditions.
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Affiliation(s)
- Kishore Reddy Venkata Thappeta
- University of Wisconsin, Milwaukee, WI, USA.,Singapore Institute of Food and Biotechnology Innovation (SIFBI), A*STAR, Singapore
| | - Kristin Ciezki
- Aurora Health Care, Milwaukee, WI, USA.,University of Wisconsin, Milwaukee, WI, USA
| | - Nydia Morales-Soto
- Eck Institute for Global Health, University of Notre Dame, IN, USA.,University of Wisconsin, Milwaukee, WI, USA
| | | | - Heidi Goodrich-Blair
- University of Tennessee, Knoxville, TN, USA.,University of Wisconsin, Madison, WI, USA
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5
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Cambon MC, Lafont P, Frayssinet M, Lanois A, Ogier JC, Pagès S, Parthuisot N, Ferdy JB, Gaudriault S. Bacterial community profile after the lethal infection of Steinernema-Xenorhabdus pairs into soil-reared Tenebrio molitor larvae. FEMS Microbiol Ecol 2020; 96:5704397. [PMID: 31942980 DOI: 10.1093/femsec/fiaa009] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 01/13/2020] [Indexed: 01/01/2023] Open
Abstract
The host microbiota may have an impact on pathogens. This is often studied in laboratory-reared hosts but rarely in individuals whose microbiota looks like that of wild animals. In this study, we modified the gut microbiota of the insect Tenebrio molitor by rearing larvae in soil sampled from the field. We showed by high throughput sequencing methods that this treatment modifies the gut microbiota so that it is more diversified than that of laboratory-reared insects, and closely resembled the one of soil-dwelling insects. To describe what the entomopathogenic bacterial symbiont Xenorhabdus (Enterobacteriaceae), vectored by the soil-dwelling nematode Steinernema, might experience in natural conditions, we studied the infestation of the soil-reared T. molitor larvae with three Steinernema-Xenorhabdus pairs. We performed the infestation at 18°C, which delays the emergence of new infective juveniles (IJs), the soil-dwelling nematode forms, but which is a temperature compatible with natural infestation. We analyzed by high throughput sequencing methods the composition of the bacterial community within the insect cadavers before the first emergences of IJs. These bacterial communities were generally characterized by one or two non-symbiont taxa. Even for highly lethal Steinernema-Xenorhabdus pairs, the symbiont does not dominate the bacterial community within the insect cadaver.
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Affiliation(s)
- Marine C Cambon
- Laboratoire Evolution et Diversité Biologique, CNRS-IRD-Université Paul Sabatier, 118 route de Narbonne, 31077 Toulouse, France.,Laboratoire Diversité, Génome et Interactions Microorganismes Insectes, INRA-Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France
| | - Pierre Lafont
- Laboratoire Evolution et Diversité Biologique, CNRS-IRD-Université Paul Sabatier, 118 route de Narbonne, 31077 Toulouse, France
| | - Marie Frayssinet
- Laboratoire Diversité, Génome et Interactions Microorganismes Insectes, INRA-Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France
| | - Anne Lanois
- Laboratoire Diversité, Génome et Interactions Microorganismes Insectes, INRA-Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France
| | - Jean-Claude Ogier
- Laboratoire Diversité, Génome et Interactions Microorganismes Insectes, INRA-Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France
| | - Sylvie Pagès
- Laboratoire Diversité, Génome et Interactions Microorganismes Insectes, INRA-Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France
| | - Nathalie Parthuisot
- Laboratoire Evolution et Diversité Biologique, CNRS-IRD-Université Paul Sabatier, 118 route de Narbonne, 31077 Toulouse, France
| | - Jean-Baptiste Ferdy
- Laboratoire Evolution et Diversité Biologique, CNRS-IRD-Université Paul Sabatier, 118 route de Narbonne, 31077 Toulouse, France
| | - Sophie Gaudriault
- Laboratoire Diversité, Génome et Interactions Microorganismes Insectes, INRA-Université de Montpellier, Place Eugène Bataillon, 34095 Montpellier, France
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Heryanto C, Eleftherianos I. Nematode endosymbiont competition: Fortune favors the fittest. Mol Biochem Parasitol 2020; 238:111298. [PMID: 32621939 DOI: 10.1016/j.molbiopara.2020.111298] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/27/2020] [Accepted: 06/29/2020] [Indexed: 01/20/2023]
Abstract
Endosymbiotic bacteria that obligately associate with entomopathogenic nematodes as a complex are a unique model system to study competition. These nematodes seek an insect host and provide entry for their endosymbionts. Through their natural products, the endosymbionts nurture their nematodes by eliminating secondary infection, providing nutrients through bioconversion of the insect cadaver, and facilitating reproduction. On one hand, they cooperatively colonize the insect host and neutralize other opportunistic biotic threats. On the other hand, inside the insect cadaver as a fighting pit, they fiercely compete for the fittest partnership that will grant them the reproductive dominance. Here, we review the protective and nurturing nature of endosymbiotic bacteria for their nematodes and how their selective preference shapes the superior nematode-endosymbiont pairs as we know today.
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Affiliation(s)
- Christa Heryanto
- Infection and Innate Immunity Lab, Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Science and Engineering Hall, 800 22nd Street NW, Washington, D.C. 20052, USA
| | - Ioannis Eleftherianos
- Infection and Innate Immunity Lab, Department of Biological Sciences, Institute for Biomedical Sciences, The George Washington University, Science and Engineering Hall, 800 22nd Street NW, Washington, D.C. 20052, USA.
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7
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Fodor A, Abate BA, Deák P, Fodor L, Gyenge E, Klein MG, Koncz Z, Muvevi J, Ötvös L, Székely G, Vozik D, Makrai L. Multidrug Resistance (MDR) and Collateral Sensitivity in Bacteria, with Special Attention to Genetic and Evolutionary Aspects and to the Perspectives of Antimicrobial Peptides-A Review. Pathogens 2020; 9:pathogens9070522. [PMID: 32610480 PMCID: PMC7399985 DOI: 10.3390/pathogens9070522] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 06/23/2020] [Accepted: 06/23/2020] [Indexed: 12/18/2022] Open
Abstract
Antibiotic poly-resistance (multidrug-, extreme-, and pan-drug resistance) is controlled by adaptive evolution. Darwinian and Lamarckian interpretations of resistance evolution are discussed. Arguments for, and against, pessimistic forecasts on a fatal “post-antibiotic era” are evaluated. In commensal niches, the appearance of a new antibiotic resistance often reduces fitness, but compensatory mutations may counteract this tendency. The appearance of new antibiotic resistance is frequently accompanied by a collateral sensitivity to other resistances. Organisms with an expanding open pan-genome, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae, can withstand an increased number of resistances by exploiting their evolutionary plasticity and disseminating clonally or poly-clonally. Multidrug-resistant pathogen clones can become predominant under antibiotic stress conditions but, under the influence of negative frequency-dependent selection, are prevented from rising to dominance in a population in a commensal niche. Antimicrobial peptides have a great potential to combat multidrug resistance, since antibiotic-resistant bacteria have shown a high frequency of collateral sensitivity to antimicrobial peptides. In addition, the mobility patterns of antibiotic resistance, and antimicrobial peptide resistance, genes are completely different. The integron trade in commensal niches is fortunately limited by the species-specificity of resistance genes. Hence, we theorize that the suggested post-antibiotic era has not yet come, and indeed might never come.
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Affiliation(s)
- András Fodor
- Department of Genetics, University of Szeged, H-6726 Szeged, Hungary;
- Correspondence: or (A.F.); (L.M.); Tel.: +36-(30)-490-9294 (A.F.); +36-(30)-271-2513 (L.M.)
| | - Birhan Addisie Abate
- Ethiopian Biotechnology Institute, Agricultural Biotechnology Directorate, Addis Ababa 5954, Ethiopia;
| | - Péter Deák
- Department of Genetics, University of Szeged, H-6726 Szeged, Hungary;
- Institute of Biochemistry, Biological Research Centre, H-6726 Szeged, Hungary
| | - László Fodor
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, P.O. Box 22, H-1581 Budapest, Hungary;
| | - Ervin Gyenge
- Hungarian Department of Biology and Ecology, Faculty of Biology and Geology, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania; (E.G.); (G.S.)
- Institute for Research-Development-Innovation in Applied Natural Sciences, Babeș-Bolyai University, 30 Fântânele St., 400294 Cluj-Napoca, Romania
| | - Michael G. Klein
- Department of Entomology, The Ohio State University, 1680 Madison Ave., Wooster, OH 44691, USA;
| | - Zsuzsanna Koncz
- Max-Planck Institut für Pflanzenzüchtungsforschung, Carl-von-Linné-Weg 10, D-50829 Köln, Germany;
| | | | - László Ötvös
- OLPE, LLC, Audubon, PA 19403-1965, USA;
- Institute of Medical Microbiology, Semmelweis University, H-1085 Budapest, Hungary
- Arrevus, Inc., Raleigh, NC 27612, USA
| | - Gyöngyi Székely
- Hungarian Department of Biology and Ecology, Faculty of Biology and Geology, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania; (E.G.); (G.S.)
- Institute for Research-Development-Innovation in Applied Natural Sciences, Babeș-Bolyai University, 30 Fântânele St., 400294 Cluj-Napoca, Romania
- Centre for Systems Biology, Biodiversity and Bioresources, Babeș-Bolyai University, 5-7 Clinicilor St., 400006 Cluj-Napoca, Romania
| | - Dávid Vozik
- Research Institute on Bioengineering, Membrane Technology and Energetics, Faculty of Engineering, University of Veszprem, H-8200 Veszprém, Hungary; or or
| | - László Makrai
- Department of Microbiology and Infectious Diseases, University of Veterinary Medicine, P.O. Box 22, H-1581 Budapest, Hungary;
- Correspondence: or (A.F.); (L.M.); Tel.: +36-(30)-490-9294 (A.F.); +36-(30)-271-2513 (L.M.)
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