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Lucas-Elío P, ElAlami T, Martínez A, Sanchez-Amat A. Marinomonas mediterranea synthesizes an R-type bacteriocin. Appl Environ Microbiol 2024; 90:e0127323. [PMID: 38169292 PMCID: PMC10870725 DOI: 10.1128/aem.01273-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 11/17/2023] [Indexed: 01/05/2024] Open
Abstract
Prophages integrated into bacterial genomes can become cryptic or defective prophages, which may evolve to provide various traits to bacterial cells. Previous research on Marinomonas mediterranea MMB-1 demonstrated the production of defective particles. In this study, an analysis of the genomes of three different strains (MMB-1, MMB-2, and MMB-3) revealed the presence of a region named MEDPRO1, spanning approximately 52 kb, coding for a defective prophage in strains MMB-1 and MMB-2. This prophage seems to have been lost in strain MMB-3, possibly due to the presence of spacers recognizing this region in an I-F CRISPR array in this strain. However, all three strains produce remarkably similar defective particles. Using strain MMB-1 as a model, mass spectrometry analyses indicated that the structural proteins of the defective particles are encoded by a second defective prophage situated within the MEDPRO2 region, spanning approximately 13 kb. This finding was further validated through the deletion of this second defective prophage. Genomic region analyses and the detection of antimicrobial activity of the defective prophage against other Marinomonas species suggest that it is an R-type bacteriocin. Marinomonas mediterranea synthesizes antimicrobial proteins with lysine oxidase activity, and the synthesis of an R-type bacteriocin constitutes an additional mechanism in microbial competition for the colonization of habitats such as the surface of marine plants.IMPORTANCEThe interactions between bacterial strains inhabiting the same environment determine the final composition of the microbiome. In this study, it is shown that some extracellular defective phage particles previously observed in Marinomonas mediterranea are in fact R-type bacteriocins showing antimicrobial activity against other Marinomonas strains. The operon coding for the R-type bacteriocin has been identified.
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Affiliation(s)
- Patricia Lucas-Elío
- Department of Genetics and Microbiology, University of Murcia, Murcia, Spain
| | - Tarik ElAlami
- Department of Genetics and Microbiology, University of Murcia, Murcia, Spain
| | - Alicia Martínez
- Department of Genetics and Microbiology, University of Murcia, Murcia, Spain
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2
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Ishii T, Tsuchida N, Hemelda NM, Saito K, Bao J, Watanabe M, Toyoda A, Matsubara T, Sato M, Toyooka K, Ishihama N, Shirasu K, Matsui H, Toyoda K, Ichinose Y, Hayashi T, Kawaguchi A, Noutoshi Y. Rhizoviticin is an alphaproteobacterial tailocin that mediates biocontrol of grapevine crown gall disease. THE ISME JOURNAL 2024; 18:wrad003. [PMID: 38365227 PMCID: PMC10811719 DOI: 10.1093/ismejo/wrad003] [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: 07/25/2023] [Revised: 10/27/2023] [Accepted: 11/06/2023] [Indexed: 02/18/2024]
Abstract
Tailocins are headless phage tail structures that mediate interbacterial antagonism. Although the prototypical tailocins, R- and F-pyocins, in Pseudomonas aeruginosa, and other predominantly R-type tailocins have been studied, their presence in Alphaproteobacteria remains unexplored. Here, we report the first alphaproteobacterial F-type tailocin, named rhizoviticin, as a determinant of the biocontrol activity of Allorhizobium vitis VAR03-1 against crown gall. Rhizoviticin is encoded by a chimeric prophage genome, one providing transcriptional regulators and the other contributing to tail formation and cell lysis, but lacking head formation genes. The rhizoviticin genome retains a nearly intact early phage region containing an integrase remnant and replication-related genes critical for downstream gene transcription, suggesting an ongoing transition of this locus from a prophage to a tailocin-coding region. Rhizoviticin is responsible for the most antagonistic activity in VAR03-1 culture supernatant against pathogenic A. vitis strain, and rhizoviticin deficiency resulted in a significant reduction in the antitumorigenic activity in planta. We identified the rhizoviticin-coding locus in eight additional A. vitis strains from diverse geographical locations, highlighting a unique survival strategy of certain Rhizobiales bacteria in the rhizosphere. These findings advance our understanding of the evolutionary dynamics of tailocins and provide a scientific foundation for employing rhizoviticin-producing strains in plant disease control.
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Affiliation(s)
- Tomoya Ishii
- Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Natsuki Tsuchida
- Faculty of Agriculture, Okayama University, Okayama 700-8530, Japan
- Present address: Division of Biological Science, Nara Institute of Science and Technology (NAIST), Ikoma, Nara 630-0192, Japan
| | - Niarsi Merry Hemelda
- Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
- Department of Biology, University of Indonesia, Depok 16424, Indonesia
| | - Kirara Saito
- Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
- Present address: Kyushu Okinawa Agricultural Research Center, National Agriculture and Food Research Organization, Miyakonojo, Miyazaki 885-0091, Japan
| | - Jiyuan Bao
- Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Megumi Watanabe
- Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
| | - Atsushi Toyoda
- Department of Genomics and Evolutionary Biology, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Takehiro Matsubara
- Okayama University Hospital Biobank, Okayama University Hospital, Okayama 700-8558, Japan
| | - Mayuko Sato
- Mass Spectrometry and Microscopy Unit, Technology Platform Division, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan
| | - Kiminori Toyooka
- Mass Spectrometry and Microscopy Unit, Technology Platform Division, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan
| | - Nobuaki Ishihama
- Plant Immunity Research Group, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan
| | - Ken Shirasu
- Plant Immunity Research Group, RIKEN Center for Sustainable Resource Science, Yokohama 230-0045, Japan
- Graduate School of Science, The University of Tokyo, Tokyo 113-8657, Japan
| | - Hidenori Matsui
- Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
- Faculty of Agriculture, Okayama University, Okayama 700-8530, Japan
| | - Kazuhiro Toyoda
- Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
- Faculty of Agriculture, Okayama University, Okayama 700-8530, Japan
| | - Yuki Ichinose
- Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
- Faculty of Agriculture, Okayama University, Okayama 700-8530, Japan
| | - Tetsuya Hayashi
- Department of Bacteriology, Graduate School of Medical Sciences, Kyushu University, Fukuoka 812-8582, Japan
| | - Akira Kawaguchi
- Western Region Agricultural Research Center (WARC), National Agricultural and Food Research Organization (NARO), Fukuyama, Hiroshima 721-8514, Japan
| | - Yoshiteru Noutoshi
- Graduate School of Environmental, Life, Natural Science and Technology, Okayama University, Okayama 700-8530, Japan
- Faculty of Agriculture, Okayama University, Okayama 700-8530, Japan
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3
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Stice SP, Jan HH, Chen HC, Nwosu L, Shin GY, Weaver S, Coutinho T, Kvitko BH, Baltrus DA. Pantailocins: phage-derived bacteriocins from Pantoea ananatis and Pantoea stewartii subsp. indologenes. Appl Environ Microbiol 2023; 89:e0092923. [PMID: 37982620 PMCID: PMC10870728 DOI: 10.1128/aem.00929-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 09/15/2023] [Indexed: 11/21/2023] Open
Abstract
IMPORTANCE Phage-derived bacteriocins (tailocins) are ribosomally synthesized structures produced by bacteria in order to provide advantages against competing strains under natural conditions. Tailocins are highly specific in their target range and have proven to be effective for the prevention and/or treatment of bacterial diseases under clinical and agricultural settings. We describe the discovery and characterization of a new tailocin locus encoded within genomes of Pantoea ananatis and Pantoea stewartii subsp. indologenes, which may enable the development of tailocins as preventative treatments against phytopathogenic infection by these species.
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Affiliation(s)
- Shaun P. Stice
- Department of Plant Pathology, University of Georgia, Athens, Georgia, USA
| | - Hsiao-Hsuan Jan
- Department of Plant Pathology, University of Georgia, Athens, Georgia, USA
| | - Hsiao-Chun Chen
- Department of Plant Pathology, University of Georgia, Athens, Georgia, USA
| | - Linda Nwosu
- Department of Plant Pathology, University of Georgia, Athens, Georgia, USA
| | - Gi Yoon Shin
- Department of Plant Pathology, University of Georgia, Athens, Georgia, USA
| | - Savannah Weaver
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
| | - Teresa Coutinho
- The Plant Center, University of Georgia, Athens, Georgia, USA
| | - Brian H. Kvitko
- Department of Plant Pathology, University of Georgia, Athens, Georgia, USA
- Department of Biochemistry, Genetics, and Microbiology, University of Pretoria, Pretoria, South Africa
| | - David A. Baltrus
- School of Animal and Comparative Biomedical Sciences, University of Arizona, Tucson, Arizona, USA
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
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4
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Heiman CM, Vacheron J, Keel C. Evolutionary and ecological role of extracellular contractile injection systems: from threat to weapon. Front Microbiol 2023; 14:1264877. [PMID: 37886057 PMCID: PMC10598620 DOI: 10.3389/fmicb.2023.1264877] [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: 07/21/2023] [Accepted: 09/26/2023] [Indexed: 10/28/2023] Open
Abstract
Contractile injection systems (CISs) are phage tail-related structures that are encoded in many bacterial genomes. These devices encompass the cell-based type VI secretion systems (T6SSs) as well as extracellular CISs (eCISs). The eCISs comprise the R-tailocins produced by various bacterial species as well as related phage tail-like structures such as the antifeeding prophages (Afps) of Serratia entomophila, the Photorhabdus virulence cassettes (PVCs), and the metamorphosis-associated contractile structures (MACs) of Pseudoalteromonas luteoviolacea. These contractile structures are released into the extracellular environment upon suicidal lysis of the producer cell and play important roles in bacterial ecology and evolution. In this review, we specifically portray the eCISs with a focus on the R-tailocins, sketch the history of their discovery and provide insights into their evolution within the bacterial host, their structures and how they are assembled and released. We then highlight ecological and evolutionary roles of eCISs and conceptualize how they can influence and shape bacterial communities. Finally, we point to their potential for biotechnological applications in medicine and agriculture.
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Affiliation(s)
- Clara Margot Heiman
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
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Heiman CM, Maurhofer M, Calderon S, Dupasquier M, Marquis J, Keel C, Vacheron J. Pivotal role of O-antigenic polysaccharide display in the sensitivity against phage tail-like particles in environmental Pseudomonas kin competition. THE ISME JOURNAL 2022; 16:1683-1693. [PMID: 35273372 PMCID: PMC9213528 DOI: 10.1038/s41396-022-01217-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 02/16/2022] [Accepted: 02/18/2022] [Indexed: 11/09/2022]
Abstract
AbstractEnvironmental pseudomonads colonize various niches including insect and plant environments. When invading these environments, bacteria are confronted with the resident microbiota. To oppose with closely related strains, they rely on narrow-spectrum weaponry such as tailocins, i.e., phage tail-like particles. Little is known about the receptors for these tailocins especially among phylogenetically closely related species. Here, we studied the interaction between an R-tailocin from Pseudomonas protegens CHA0 and a targeted kin, Pseudomonas protegens Pf-5. Using genome-wide transposon insertion sequencing, we identified that lipopolysaccharides are involved in the sensitivity of Pf-5 towards the tailocin of CHA0. By generating Pf-5 lipopolysaccharide mutants and exposing them to extracted tailocin, we specified the two O-antigenic polysaccharides (O-PS) targeted by the tailocin. We affirmed the role of these O-PS through competition assays in vitro as well as in insects. Further, we demonstrate that O-PS are double-edge swords that are responsible for the sensitivity of P. protegens towards tailocins and phages produced by their kin, but shield bacteria from the immune system of the insect. Our results shed light on the trade-off that bacteria are confronted with, where specific O-PS decorations can both be of benefit or disadvantage depending on the host environment and its bacterial inhabitants.
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6
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Sun W, Liang X, Zhu C, Xu Y, Ding Y, Huang YP. Regulation of maltocin synthesis in Stenotrophomonas maltophilia by positive and negative regulators. Res Microbiol 2022; 173:103956. [DOI: 10.1016/j.resmic.2022.103956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 04/25/2022] [Accepted: 05/05/2022] [Indexed: 11/30/2022]
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Snopková K, Dufková K, Chamrád I, Lenobel R, Čejková D, Kosina M, Hrala M, Holá V, Sedláček I, Šmajs D. Pyocin-mediated antagonistic interactions in Pseudomonas spp. isolated in James Ross Island, Antarctica. Environ Microbiol 2021; 24:1294-1307. [PMID: 34735036 DOI: 10.1111/1462-2920.15809] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 09/15/2021] [Accepted: 10/05/2021] [Indexed: 11/30/2022]
Abstract
Interactions within bacterial communities are frequently mediated by the production of antimicrobial agents. Despite the increasing interest in research of new antimicrobials, studies describing antagonistic interactions among cold-adapted microorganisms are still rare. Our study assessed the antimicrobial interactions of 36 Antarctic Pseudomonas spp. and described the genetic background of these interactions in selected strains. The overall bacteriocinogeny was greater compared to mesophilic Pseudomonas non-aeruginosa species. R-type tailocins were detected on transmission electron micrographs in 16 strains (44.4%); phylogenetic analysis of the corresponding gene clusters revealed that the P. prosekii CCM 8878 tailocin was related to the Rp3 group, whereas the tailocin in Pseudomonas sp. CCM 8880 to the Rp4 group. Soluble antimicrobials were produced by eight strains (22.-2%); gene mining found pyocin L homologues in the genomes of P. prosekii CCM 8881 and CCM 8879 and pyocin S9-like homologues in P. prosekii CCM 8881 and Pseudomonas sp. CCM 8880. Analysis of secretomes confirmed the production of all S- and L-type pyocin genes. Our results suggest that bacteriocin-based inhibition plays an important role in interactions among Antarctic soil bacteria, and these native, cold-adapted microorganisms could be a promising source of new antimicrobials.
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Affiliation(s)
- Kateřina Snopková
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - Kristýna Dufková
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - Ivo Chamrád
- Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany of the Czech Academy of Sciences, Šlechtitelů 241/27, Olomouc-Holice, 779 00, Czech Republic
| | - René Lenobel
- Laboratory of Growth Regulators, Faculty of Science, Palacký University and Institute of Experimental Botany of the Czech Academy of Sciences, Šlechtitelů 241/27, Olomouc-Holice, 779 00, Czech Republic
| | - Darina Čejková
- Veterinary Research Institute, Hudcova 296/70, Brno, 621 00, Czech Republic
| | - Marcel Kosina
- Department of Experimental Biology, Czech Collection of Microorganisms, Faculty of Science, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - Matěj Hrala
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - Veronika Holá
- Faculty of Medicine, Institute for Microbiology, Masaryk University and St. Anne's University Hospital Brno, Pekařská 664/53, Brno, 656 91, Czech Republic
| | - Ivo Sedláček
- Department of Experimental Biology, Czech Collection of Microorganisms, Faculty of Science, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
| | - David Šmajs
- Department of Biology, Faculty of Medicine, Masaryk University, Kamenice 753/5, Brno, 625 00, Czech Republic
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8
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Investigating the process of sheath maturation in Anti-feeding prophage- a phage tail-like protein translocation structure. J Bacteriol 2021; 203:e0010421. [PMID: 34370558 DOI: 10.1128/jb.00104-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The Anti-feeding prophage (Afp) produced by the bacterium Serratia entomophila is the archetype, external contractile injection system (eCIS). Afp and its orthologues are characterized by three sheath proteins while contractile bacteriophages and pyocins encode only one. Using targeted mutagenesis, transmission electron microscopy (TEM) and pull-down studies, we interrogated the roles of the three sheath proteins (Afp2, Afp3 and Afp4) in Afp assembly, in particular, the interaction between the two sequence-related helical-sheath forming proteins Afp2 and Afp3 and their cross-talks with the tail termination sheath capping protein (Trp) Afp16 in the sheath maturation process. The expressed assemblies for afp2- mutant were mostly a mixture of isolated tail fibres, detached baseplates without tail fibres and sheath-less, inner tube baseplate complexes (TBC) of length similar to that in mature Afp, which were surrounded in many cases by fibrillar polymerized material. In the afp3- mutant, variable length TBC with similar but shorter length fibrillar polymerized material, largely bereft of tail-fibres, were observed; while, only detached baseplate assemblies were seen for the afp4- mutant. Further, we found that a) only trans complementation of afp2 with its mutated counterpart restored mature Afp particles with full biological activity, b) purified Afp3 pulled down Afp2 by forming a SDS-resistant complex but not vice versa, c) Afp16 had a greater affinity for binding Afp2 or Afp3 than Afp4 and d) Afp4 is required for the association of the polymerized sheath on the baseplate via Afp2. A proposed model for sheath maturation and assembly in Afp is presented. Importance Members of the contractile bacteriophage related but evolutionarily divergent, eCIS contain not one but three sheath proteins - two of which, namely Afp2 and Afp3 in the Afp, arranged as alternate hexameric stacks constitute the helical sheath. We revealed that Afp2 and Afp3 even though they are highly similar, possess markedly distinct, crucial roles in Afp assembly. We find that Afp3, by virtue of its interaction with the tail terminating protein Afp16, regulates tube and sheath length while Afp2 is critical to proper sheath polymerisation and assembly of the baseplate. The resulting model for the Afp assembly will further guide in the manipulation of Afp and its related eCISs as nano delivery vehicles for pest control and phage therapy.
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9
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Carim S, Azadeh AL, Kazakov AE, Price MN, Walian PJ, Lui LM, Nielsen TN, Chakraborty R, Deutschbauer AM, Mutalik VK, Arkin AP. Systematic discovery of pseudomonad genetic factors involved in sensitivity to tailocins. THE ISME JOURNAL 2021; 15:2289-2305. [PMID: 33649553 PMCID: PMC8319346 DOI: 10.1038/s41396-021-00921-1] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 01/14/2021] [Accepted: 02/01/2021] [Indexed: 12/13/2022]
Abstract
Tailocins are bactericidal protein complexes produced by a wide variety of bacteria that kill closely related strains and may play a role in microbial community structure. Thanks to their high specificity, tailocins have been proposed as precision antibacterial agents for therapeutic applications. Compared to tailed phages, with whom they share an evolutionary and morphological relationship, bacterially produced tailocins kill their host upon production but producing strains display resistance to self-intoxication. Though lipopolysaccharide (LPS) has been shown to act as a receptor for tailocins, the breadth of factors involved in tailocin sensitivity, and the mechanisms behind resistance to self-intoxication, remain unclear. Here, we employed genome-wide screens in four non-model pseudomonads to identify mutants with altered fitness in the presence of tailocins produced by closely related pseudomonads. Our mutant screens identified O-antigen composition and display as most important in defining sensitivity to our tailocins. In addition, the screens suggest LPS thinning as a mechanism by which resistant strains can become more sensitive to tailocins. We validate many of these novel findings, and extend these observations of tailocin sensitivity to 130 genome-sequenced pseudomonads. This work offers insights into tailocin-bacteria interactions, informing the potential use of tailocins in microbiome manipulation and antibacterial therapy.
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Affiliation(s)
- Sean Carim
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Ashley L Azadeh
- Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Alexey E Kazakov
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Morgan N Price
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Peter J Walian
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Lauren M Lui
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Torben N Nielsen
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Romy Chakraborty
- Climate and Ecosystem Sciences, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Adam M Deutschbauer
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Vivek K Mutalik
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
| | - Adam P Arkin
- Innovative Genomics Institute, University of California, Berkeley, CA, USA.
- Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
- Department of Bioengineering, University of California, Berkeley, CA, USA.
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10
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Vacheron J, Heiman CM, Keel C. Live cell dynamics of production, explosive release and killing activity of phage tail-like weapons for Pseudomonas kin exclusion. Commun Biol 2021; 4:87. [PMID: 33469108 PMCID: PMC7815802 DOI: 10.1038/s42003-020-01581-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 12/07/2020] [Indexed: 01/29/2023] Open
Abstract
Interference competition among bacteria requires a highly specialized, narrow-spectrum weaponry when targeting closely-related competitors while sparing individuals from the same clonal population. Here we investigated mechanisms by which environmentally important Pseudomonas bacteria with plant-beneficial activity perform kin interference competition. We show that killing between phylogenetically closely-related strains involves contractile phage tail-like devices called R-tailocins that puncture target cell membranes. Using live-cell imaging, we evidence that R-tailocins are produced at the cell center, transported to the cell poles and ejected by explosive cell lysis. This enables their dispersal over several tens of micrometers to reach targeted cells. We visualize R-tailocin-mediated competition dynamics between closely-related Pseudomonas strains at the single-cell level, both in non-induced condition and upon artificial induction. We document the fatal impact of cellular self-sacrifice coupled to deployment of phage tail-like weaponry in the microenvironment of kin bacterial competitors, emphasizing the necessity for microscale assessment of microbial competitions.
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Affiliation(s)
- Jordan Vacheron
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland.
| | - Clara Margot Heiman
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland
| | - Christoph Keel
- Department of Fundamental Microbiology, University of Lausanne, CH-1015, Lausanne, Switzerland.
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11
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Vachher M, Sen A, Kapila R, Nigam A. Microbial therapeutic enzymes: A promising area of biopharmaceuticals. CURRENT RESEARCH IN BIOTECHNOLOGY 2021. [DOI: 10.1016/j.crbiot.2021.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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12
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Zboralski A, Filion M. Genetic factors involved in rhizosphere colonization by phytobeneficial Pseudomonas spp. Comput Struct Biotechnol J 2020; 18:3539-3554. [PMID: 33304453 PMCID: PMC7711191 DOI: 10.1016/j.csbj.2020.11.025] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 11/10/2020] [Accepted: 11/12/2020] [Indexed: 12/13/2022] Open
Abstract
Plant growth-promoting rhizobacteria (PGPR) actively colonize the soil portion under the influence of plant roots, called the rhizosphere. Many plant-beneficial Pseudomonas spp. have been characterized as PGPR. They are ubiquitous rod-shaped motile Gram-negative bacteria displaying a high metabolic versatility. Their capacity to protect plants from pathogens and improve plant growth closely depends on their rhizosphere colonization abilities. Various molecular and cellular mechanisms are involved in this complex process, such as chemotaxis, biofilm formation, secondary metabolites biosynthesis, metabolic versatility, and evasion of plant immunity. The burst in Pseudomonas spp. genome sequencing in recent years has been crucial to better understand how they colonize the rhizosphere. In this review, we discuss the recent advances regarding these mechanisms and the underlying bacterial genetic factors required for successful rhizosphere colonization.
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Affiliation(s)
- Antoine Zboralski
- Department of Biology, Université de Moncton, Moncton, NB E1A 3E9, Canada
| | - Martin Filion
- Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Jean-sur-Richelieu, QC J3B 3E6, Canada
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13
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crAssphage genomes identified in fecal samples of an adult and infants with evidence of positive genomic selective pressure within tail protein genes. Virus Res 2020; 292:198219. [PMID: 33137401 DOI: 10.1016/j.virusres.2020.198219] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 10/06/2020] [Accepted: 10/26/2020] [Indexed: 01/21/2023]
Abstract
crAssphages are a broad group of diverse bacteriophages in the order Caudovirales that have been found to be highly abundant in the human gastrointestinal tract. Despite their high prevalence, we have an incomplete understanding of how crAssphages shape and respond to ecological and evolutionary dynamics in the gut. Here, we report genomes of crAssphages from feces of one South African woman and three infants. Across the complete genome sequences of the South African crAssphages described here, we identify particularly elevated positive selection in RNA polymerase and phage tail protein encoding genes, contrasted against purifying selection, genome-wide. We further validate these findings against a crAssphage genome from previous studies. Together, our results suggest hotspots of selection within crAssphage RNA polymerase and phage tail protein encoding genes are potentially mediated by interactions between crAssphages and their bacterial partners.
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Rooney WM, Chai R, Milner JJ, Walker D. Bacteriocins Targeting Gram-Negative Phytopathogenic Bacteria: Plantibiotics of the Future. Front Microbiol 2020; 11:575981. [PMID: 33042091 PMCID: PMC7530242 DOI: 10.3389/fmicb.2020.575981] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 08/25/2020] [Indexed: 12/12/2022] Open
Abstract
Gram-negative phytopathogenic bacteria are a significant threat to food crops. These microbial invaders are responsible for a plethora of plant diseases and can be responsible for devastating losses in crops such as tomatoes, peppers, potatoes, olives, and rice. Current disease management strategies to mitigate yield losses involve the application of chemicals which are often harmful to both human health and the environment. Bacteriocins are small proteinaceous antibiotics produced by bacteria to kill closely related bacteria and thereby establish dominance within a niche. They potentially represent a safer alternative to chemicals when used in the field. Bacteriocins typically show a high degree of selectivity toward their targets with no off-target effects. This review outlines the current state of research on bacteriocins active against Gram-negative phytopathogenic bacteria. Furthermore, we will examine the feasibility of weaponizing bacteriocins for use as a treatment for bacterial plant diseases.
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Affiliation(s)
- William M. Rooney
- Plant Science Group, School of Life Sciences, Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, United Kingdom
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Ray Chai
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
| | - Joel J. Milner
- Plant Science Group, School of Life Sciences, Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, United Kingdom
| | - Daniel Walker
- College of Medical, Veterinary and Life Sciences, Institute of Infection, Immunity and Inflammation, University of Glasgow, Glasgow, United Kingdom
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15
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Kandel PP, Baltrus DA, Hockett KL. Pseudomonas Can Survive Tailocin Killing via Persistence-Like and Heterogenous Resistance Mechanisms. J Bacteriol 2020; 202:e00142-20. [PMID: 32312747 PMCID: PMC7283598 DOI: 10.1128/jb.00142-20] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 04/16/2020] [Indexed: 12/14/2022] Open
Abstract
Phage tail-like bacteriocins (tailocins) are bacterially produced protein toxins that mediate competitive interactions between cocolonizing bacteria. Both theoretical and experimental research has shown there are intransitive interactions between bacteriocin-producing, bacteriocin-sensitive, and bacteriocin-resistant populations, whereby producers outcompete sensitive cells, sensitive cells outcompete resistant cells, and resistant cells outcompete producers. These so-called rock-paper-scissors dynamics explain how all three populations occupy the same environment, without one driving the others extinct. Using Pseudomonas syringae as a model, we demonstrate that otherwise sensitive cells survive bacteriocin exposure through a physiological mechanism. This mechanism allows cells to survive bacteriocin killing without acquiring resistance. We show that a significant fraction of the target cells that survive a lethal dose of tailocin did not exhibit any detectable increase in survival during a subsequent exposure. Tailocin persister cells were more prevalent in stationary- rather than log-phase cultures. Of the fraction of cells that gained detectable resistance, there was a range from complete (insensitive) to incomplete (partially sensitive) resistance. By using genomic sequencing and genetic engineering, we showed that a mutation in a hypothetical gene containing 8 to 10 transmembrane domains causes tailocin high persistence and that genes of various glycosyltransferases cause incomplete and complete tailocin resistance. Importantly, of the several classes of mutations, only those causing complete tailocin resistance compromised host fitness. This result indicates that bacteria likely utilize persistence to survive bacteriocin-mediated killing without suffering the costs associated with resistance. This research provides important insight into how bacteria can escape the trap of fitness trade-offs associated with gaining de novo tailocin resistance.IMPORTANCE Bacteriocins are bacterially produced protein toxins that are proposed as antibiotic alternatives. However, a deeper understanding of the responses of target bacteria to bacteriocin exposure is lacking. Here, we show that target cells of Pseudomonas syringae survive lethal bacteriocin exposure through both physiological persistence and genetic resistance mechanisms. Cells that are not growing rapidly rely primarily on persistence, whereas those growing rapidly are more likely to survive via resistance. We identified various mutations in lipopolysaccharide biogenesis-related regions involved in tailocin persistence and resistance. By assessing host fitness of various classes of mutants, we showed that persistence and subtle resistance are mechanisms P. syringae uses to survive competition and preserve host fitness. These results have important implications for developing bacteriocins as alternative therapeutic agents.
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Affiliation(s)
- Prem P Kandel
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, Pennsylvania, USA
| | - David A Baltrus
- School of Plant Sciences, University of Arizona, Tucson, Arizona, USA
| | - Kevin L Hockett
- Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, Pennsylvania, USA
- The Huck Institutes of the Life Sciences, The Pennsylvania State University, University Park, Pennsylvania, USA
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16
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De Vrieze M, Varadarajan AR, Schneeberger K, Bailly A, Rohr RP, Ahrens CH, Weisskopf L. Linking Comparative Genomics of Nine Potato-Associated Pseudomonas Isolates With Their Differing Biocontrol Potential Against Late Blight. Front Microbiol 2020; 11:857. [PMID: 32425922 PMCID: PMC7204214 DOI: 10.3389/fmicb.2020.00857] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Accepted: 04/09/2020] [Indexed: 01/22/2023] Open
Abstract
For plants, the advantages of associating with beneficial bacteria include plant growth promotion, reduction of abiotic and biotic stresses and enhanced protection against various pests and diseases. Beneficial bacteria rightly equipped for successful plant colonization and showing antagonistic activity toward plant pathogens seem to be actively recruited by plants. To gain more insights into the genetic determinants responsible for plant colonization and antagonistic activities, we first sequenced and de novo assembled the complete genomes of nine Pseudomonas strains that had exhibited varying antagonistic potential against the notorious oomycete Phytophthora infestans, placed them into the phylogenomic context of known Pseudomonas biocontrol strains and carried out a comparative genomic analysis to define core, accessory (i.e., genes found in two or more, but not all strains) and unique genes. Next, we assessed the colonizing abilities of these strains and used bioassays to characterize their inhibitory effects against different stages of P. infestans' lifecycle. The phenotype data were then correlated with genotype information, assessing over three hundred genes encoding known factors for plant colonization and antimicrobial activity as well as secondary metabolite biosynthesis clusters predicted by antiSMASH. All strains harbored genes required for successful plant colonization but also distinct arsenals of antimicrobial compounds. We identified genes coding for phenazine, hydrogen cyanide, 2-hexyl, 5-propyl resorcinol and pyrrolnitrin synthesis, as well as various siderophores, pyocins and type VI secretion systems. Additionally, the comparative genomic analysis revealed about a hundred accessory genes putatively involved in anti-Phytophthora activity, including a type II secretion system (T2SS), several peptidases and a toxin. Transcriptomic studies and mutagenesis are needed to further investigate the putative involvement of the novel candidate genes and to identify the various mechanisms involved in the inhibition of P. infestans by different Pseudomonas strains.
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Affiliation(s)
- Mout De Vrieze
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Adithi R. Varadarajan
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics & SIB Swiss Institute of Bioinformatics, Wädenswil, Switzerland
| | - Kerstin Schneeberger
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics & SIB Swiss Institute of Bioinformatics, Wädenswil, Switzerland
| | - Aurélien Bailly
- Department of Plant and Microbial Biology, University of Zurich, Zurich, Switzerland
| | - Rudolf P. Rohr
- Department of Biology, University of Fribourg, Fribourg, Switzerland
| | - Christian H. Ahrens
- Agroscope, Research Group Molecular Diagnostics, Genomics and Bioinformatics & SIB Swiss Institute of Bioinformatics, Wädenswil, Switzerland
| | - Laure Weisskopf
- Department of Biology, University of Fribourg, Fribourg, Switzerland
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17
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Siranosian BA, Tamburini FB, Sherlock G, Bhatt AS. Acquisition, transmission and strain diversity of human gut-colonizing crAss-like phages. Nat Commun 2020; 11:280. [PMID: 31941900 PMCID: PMC6962324 DOI: 10.1038/s41467-019-14103-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 12/04/2019] [Indexed: 12/28/2022] Open
Abstract
CrAss-like phages are double-stranded DNA viruses that are prevalent in human gut microbiomes. Here, we analyze gut metagenomic data from mother-infant pairs and patients undergoing fecal microbiota transplantation to evaluate the patterns of acquisition, transmission and strain diversity of crAss-like phages. We find that crAss-like phages are rarely detected at birth but are increasingly prevalent in the infant microbiome after one month of life. We observe nearly identical genomes in 50% of cases where the same crAss-like clade is detected in both the mother and the infant, suggesting vertical transmission. In cases of putative transmission of prototypical crAssphage (p-crAssphage), we find that a subset of strains present in the mother are detected in the infant, and that strain diversity in infants increases with time. Putative tail fiber proteins are enriched for nonsynonymous strain variation compared to other genes, suggesting a potential evolutionary benefit to maintaining strain diversity in specific genes. Finally, we show that p-crAssphage can be acquired through fecal microbiota transplantation.
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Affiliation(s)
| | | | - Gavin Sherlock
- Department of Genetics, Stanford University, Stanford, CA, USA
| | - Ami S Bhatt
- Department of Genetics, Stanford University, Stanford, CA, USA.
- Department of Medicine, Division of Hematology, Stanford University, Stanford, CA, USA.
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18
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Characterization of the bacteriocins and the PrtR regulator in a plant-associated Pseudomonas strain. J Biotechnol 2020; 307:182-192. [DOI: 10.1016/j.jbiotec.2019.11.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 09/16/2019] [Accepted: 11/03/2019] [Indexed: 11/20/2022]
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19
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Koonin EV, Makarova KS, Wolf YI, Krupovic M. Evolutionary entanglement of mobile genetic elements and host defence systems: guns for hire. Nat Rev Genet 2019; 21:119-131. [PMID: 31611667 DOI: 10.1038/s41576-019-0172-9] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2019] [Indexed: 12/12/2022]
Abstract
All cellular life forms are afflicted by diverse genetic parasites, including viruses and other types of mobile genetic elements (MGEs), and have evolved multiple, diverse defence systems that protect them from MGE assault via different mechanisms. Here, we provide our perspectives on how recent evidence points to tight evolutionary connections between MGEs and defence systems that reach far beyond the proverbial arms race. Defence systems incur a fitness cost for the hosts; therefore, at least in prokaryotes, horizontal mobility of defence systems, mediated primarily by MGEs, is essential for their persistence. Moreover, defence systems themselves possess certain features of selfish elements. Common components of MGEs, such as site-specific nucleases, are 'guns for hire' that can also function as parts of defence mechanisms and are often shuttled between MGEs and defence systems. Thus, evolutionary and molecular factors converge to mould the multifaceted, inextricable connection between MGEs and anti-MGE defence systems.
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Affiliation(s)
- Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, USA.
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, USA
| | - Yuri I Wolf
- National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD, USA
| | - Mart Krupovic
- Department of Microbiology, Institut Pasteur, Paris, France.
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20
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Ghequire MGK, De Mot R. LlpB represents a second subclass of lectin-like bacteriocins. Microb Biotechnol 2019; 12:567-573. [PMID: 30702207 PMCID: PMC6465234 DOI: 10.1111/1751-7915.13373] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 01/14/2019] [Accepted: 01/15/2019] [Indexed: 12/11/2022] Open
Abstract
Bacteriocins are secreted bacterial proteins that selectively kill related strains. Lectin-like bacteriocins are atypical bacteriocins not requiring a cognate immunity factor and have been primarily studied in Pseudomonas. These so-called LlpAs are composed of a tandem of B-lectin domains. One domain interacts with d-rhamnose residues in the common polysaccharide antigen of Pseudomonas lipopolysaccharide (LPS). The other lectin domain is crucial for interference with the outer membrane protein assembly machinery by interacting with surface-exposed loops of its central component BamA. Via genome mining, we identified a second subclass of Pseudomonas lectin-like proteins, termed LlpB, consisting of a single B-lectin domain. We show that these proteins also display bactericidal activity. Among LlpB-resistant transposon mutants of an LlpB-susceptible Pseudomonas strain, a major subset was hit in an acyltransferase gene, predicted to be involved in LPS core modification, hereby suggesting that LlpBs equally attach to LPS for surface anchoring. This indicates that LPS binding and target strain specificity are condensed in a single B-lectin domain. The identification of this second subclass of lectin-like bacteriocins further expands the toolbox of antibacterial warfare deployed by bacteria and holds potential for their integration in biotechnological applications.
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Affiliation(s)
- Maarten G. K. Ghequire
- Centre of Microbial and Plant GeneticsKU LeuvenKasteelpark Arenberg 20 bus 24603001HeverleeBelgium
| | - René De Mot
- Centre of Microbial and Plant GeneticsKU LeuvenKasteelpark Arenberg 20 bus 24603001HeverleeBelgium
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21
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Engineering of receptor-binding proteins in bacteriophages and phage tail-like bacteriocins. Biochem Soc Trans 2019; 47:449-460. [PMID: 30783013 DOI: 10.1042/bst20180172] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 01/21/2019] [Accepted: 01/28/2019] [Indexed: 12/23/2022]
Abstract
Bacteriophages and phage tail-like bacteriocins (PTLBs) rely on receptor-binding proteins (RBPs) located in tail fibers or spikes for an initial and specific interaction with susceptible bacteria. Bacteriophages kill bacteria through a lytic, replicative cycle, whereas PTLBs kill the target through membrane depolarization in a single hit mechanism. Extensive efforts in the engineering of RBPs of both phages and PTLBs have been undertaken to obtain a greater understanding of the structural organization of RBPs. In addition, a major goal of engineering RBPs of phages and PTLBs is the production of antibacterials with a customized spectrum. Swapping of the RBP of phages and PTLBs results in a shift in activity spectrum in accordance with the spectrum of the new RBP. The engineering of strictly virulent phages with new RBPs required significant technical advances in the past decades, whereas the engineering of RBPs of PTLBs relied on the traditional molecular techniques used for the manipulation of bacteria and was thus relatively straightforward. While phages and PTLBs share their potential for specificity tuning, specific features of phages such as their lytic killing mechanism, their self-replicative nature and thus different pharmacokinetics and their potential to co-evolve are clear differentiators compared with PTLBs in terms of their antibacterial use.
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22
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Salazar AJ, Sherekar M, Tsai J, Sacchettini JC. R pyocin tail fiber structure reveals a receptor-binding domain with a lectin fold. PLoS One 2019; 14:e0211432. [PMID: 30721244 PMCID: PMC6363177 DOI: 10.1371/journal.pone.0211432] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/14/2019] [Indexed: 01/07/2023] Open
Abstract
R pyocins are ɸCTX-like myophage tailocins of Pseudomonas sp. Adsorption of R pyocins to target strains occurs by the interaction of tail fiber proteins with core lipopolysaccharide (LPS). Here, we demonstrate that N-terminally truncated R pyocin tail fibers corresponding to a region of variation between R-subtypes are sufficient to bind target strains according to R-subtype. We also report the crystal structures of these tail fiber proteins and show that they form an elongated helical trimer composed of three domains arranged linearly from N- to C-terminus: a baseplate proximal head, medial shaft, and distal foot. The head and shaft domains contain novel structural motifs. The foot domain, however, is composed of a conserved jellyroll fold and shares high structural similarity to the tail fiber of myophage AP22, podophage tailspike C-terminal domains (LKA-1 and ɸ297), and several eukaryotic adhesins (discoidin I/II, agglutinin, and octocoral lectin). Many of these proteins bind polysaccharides by means of their distal loop network, a series of highly variable loops at one end of the conserved jellyroll fold backbone. Our structures reveal that the majority of R-subtype specific polymorphisms cluster in patches covering a cleft formed at the oligomeric interface of the head domain and in a large patch covering much of the foot domain, including the distal loop network. Based on the structural variation in distal loops within the foot region, we propose that the foot is the primary sugar-binding domain of R pyocins and R-subtype specific structural differences in the foot domain distal loop network are responsible for binding target strains in an R-subtype dependent manner.
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Affiliation(s)
- Adam J. Salazar
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States of America
| | - Mukul Sherekar
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States of America
| | - Jennifer Tsai
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States of America
| | - James C. Sacchettini
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX, United States of America
- * E-mail:
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23
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Ghequire MGK, Öztürk B, De Mot R. Lectin-Like Bacteriocins. Front Microbiol 2018; 9:2706. [PMID: 30483232 PMCID: PMC6240691 DOI: 10.3389/fmicb.2018.02706] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 10/23/2018] [Indexed: 12/22/2022] Open
Abstract
Bacteria produce a diverse array of antagonistic compounds to restrict growth of microbial rivals. Contributing to this warfare are bacteriocins: secreted antibacterial peptides, proteins and multi-protein complexes. These compounds typically eliminate competitors closely related to the producer. Lectin-like bacteriocins (LlpAs) constitute a distinct class of such proteins, produced by Pseudomonas as well as some other proteobacterial genera. LlpAs share a common architecture consisting of two B-lectin domains, followed by a short carboxy-terminal extension. Two surface-exposed moieties on susceptible Pseudomonas cells are targeted by the respective lectin modules. The carboxy-terminal domain binds D-rhamnose residues present in the lipopolysaccharide layer, whereas the amino-terminal domain interacts with a polymorphic external loop of the outer-membrane protein insertase BamA, hence determining selectivity. The absence of a toxin-immunity module as found in modular bacteriocins and other polymorphic toxin systems, hints toward a novel mode of killing initiated at the cellular surface, not requiring bacteriocin import. Despite significant progress in understanding the function of LlpAs, outstanding questions include the secretion machinery recruited by lectin-like bacteriocins for their release, as well as a better understanding of the environmental signals initiating their expression.
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Affiliation(s)
| | - Başak Öztürk
- Leibniz-Institut DSMZ-Deutsche Sammlung von Mikroorganismen und Zellkulturen, Braunschweig, Germany
| | - René De Mot
- Centre of Microbial and Plant Genetics, KU Leuven, Leuven, Belgium
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Pseudomonas chlororaphis Produces Multiple R-Tailocin Particles That Broaden the Killing Spectrum and Contribute to Persistence in Rhizosphere Communities. Appl Environ Microbiol 2018; 84:AEM.01230-18. [PMID: 30030224 DOI: 10.1128/aem.01230-18] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 07/10/2018] [Indexed: 12/18/2022] Open
Abstract
R-tailocins are high-molecular-weight bacteriocins resembling bacteriophage tails. Pseudomonas chlororaphis 30-84 is a plant growth-promoting rhizobacterial (PGPR) strain that produces two distinct R-tailocin particles with different killing spectra. The two R-tailocins have different evolutionary histories but are released by the same lysis cassette. A previous study showed that both tailocins are important for pairwise competition with susceptible rhizosphere-colonizing strains; however, the broader role of tailocins in competition with the native rhizosphere microbiome was not tested. Genomic analysis of the P. chlororaphis 30-84 R-tailocin gene cluster uncovered the presence of three tail fiber genes in the tailocin 2 genetic module that could potentially result in tailocin 2 particles having different tail fibers and thus a wider killing spectrum. In this study, the tail fibers were found to incorporate onto different tailocin 2 particles, each with a distinct killing spectrum. A loss of production of one or both tailocins resulted in decreased P. chlororaphis 30-84 persistence within the wheat rhizosphere when in competition with the native microflora but not bulk soil. The capacity to produce three different versions of a single tailocin, each having one of three different types of tail fibers, is a previously unreported mechanism that leads to a broader R-tailocin killing spectrum. This study also provides evidence for the function of R-tailocins in competition with rhizosphere microbiome communities but not in bulk soil.IMPORTANCE Although R-tailocin gene clusters typically encode one tail fiber protein, three tail fiber-resembling genes were identified in association with one of the two sets of R-tailocin genes within the tailocin cluster of P. chlororaphis 30-84 and other sequenced P. chlororaphis strain genomes. This study confirmed that P. chlororaphis 30-84 not only produces two distinct tailocins, but that one of them is produced with three different types of tail fibers. This is a previously unreported strategy to increase the breadth of strains targeted by an R-tailocin. Our finding that R-tailocins produced by a PGPR Pseudomonas strain enhanced its persistence within the wheat rhizosphere microbiome confirms that R-tailocin production contributes to the population dynamics of rhizobacterial communities.
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Príncipe A, Fernandez M, Torasso M, Godino A, Fischer S. Effectiveness of tailocins produced by Pseudomonas fluorescens SF4c in controlling the bacterial-spot disease in tomatoes caused by Xanthomonas vesicatoria. Microbiol Res 2018; 212-213:94-102. [DOI: 10.1016/j.micres.2018.05.010] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 04/13/2018] [Accepted: 05/12/2018] [Indexed: 01/24/2023]
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Abstract
Bacteria host an arsenal of antagonism-mediating molecules to combat for ecologic space. Bacteriocins represent a pivotal group of secreted antibacterial peptides and proteins assisting in this fight, mainly eliminating relatives. Colicin M, a model for peptidoglycan-interfering bacteriocins in Gram-negative bacteria, appears to be part of a set of polymorphic toxins equipped with such a catalytic domain (ColM) targeting lipid II. Diversifying recombination has enabled parasitism of different receptors and has also given rise to hybrid bacteriocins in which ColM is associated with another toxin module. Remarkably, ColM toxins have recruited a diverse array of immunity partners, comprising cytoplasmic membrane-associated proteins with different topologies. Together, these findings suggest that different immunity mechanisms have evolved for ColM, in contrast to bacteriocins with nuclease activities.
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27
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Affiliation(s)
- Dean Scholl
- AvidBiotics Corp., South San Francisco, California 94080;,
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28
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Brackmann M, Nazarov S, Wang J, Basler M. Using Force to Punch Holes: Mechanics of Contractile Nanomachines. Trends Cell Biol 2017; 27:623-632. [DOI: 10.1016/j.tcb.2017.05.003] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 05/10/2017] [Accepted: 05/12/2017] [Indexed: 12/25/2022]
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29
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A widespread family of polymorphic toxins encoded by temperate phages. BMC Biol 2017; 15:75. [PMID: 28851366 PMCID: PMC5576092 DOI: 10.1186/s12915-017-0415-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 08/07/2017] [Indexed: 12/21/2022] Open
Abstract
Background Polymorphic toxins (PTs) are multi-domain bacterial exotoxins belonging to distinct families that share common features in terms of domain organization. PTs are found in all major bacterial clades, including many toxic effectors of type V and type VI secretion systems. PTs modulate the dynamics of microbial communities by killing or inhibiting the growth of bacterial competitors lacking protective immunity proteins. Results In this work, we identified a novel widespread family of PTs, named MuF toxins, which were exclusively encoded within temperate phages and their prophages. By analyzing the predicted proteomes of 1845 bacteriophages and 2464 bacterial genomes, we found that MuF-containing proteins were frequently part of the DNA packaging module of tailed phages. Interestingly, MuF toxins were abundant in the human gut microbiome. Conclusions Our results uncovered the presence of the MuF toxin family in the temperate phages of Firmicutes. The MuF toxin family is likely to play an important role in the ecology of the human microbiota where pathogens and commensal species belonging to the Firmicutes are abundant. We propose that MuF toxins could be delivered by phages into host bacteria and either influence the lysogeny decision or serve as bacterial weapons by inhibiting the growth of competing bacteria. Electronic supplementary material The online version of this article (doi:10.1186/s12915-017-0415-1) contains supplementary material, which is available to authorized users.
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30
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Effect of a Pseudomonas fluorescens tailocin against phytopathogenic Xanthomonas observed by atomic force microscopy. J Biotechnol 2017; 256:13-20. [DOI: 10.1016/j.jbiotec.2017.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 06/19/2017] [Accepted: 07/03/2017] [Indexed: 11/19/2022]
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31
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Pseudomonas chlororaphis Produces Two Distinct R-Tailocins That Contribute to Bacterial Competition in Biofilms and on Roots. Appl Environ Microbiol 2017; 83:AEM.00706-17. [PMID: 28526791 DOI: 10.1128/aem.00706-17] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2017] [Accepted: 05/13/2017] [Indexed: 12/13/2022] Open
Abstract
R-type tailocins are high-molecular-weight bacteriocins that resemble bacteriophage tails and are encoded within the genomes of many Pseudomonas species. In this study, analysis of the P. chlororaphis 30-84 R-tailocin gene cluster revealed that it contains the structural components to produce two R-tailocins of different ancestral origins. Two distinct R-tailocin populations differing in length were observed in UV-induced lysates of P. chlororaphis 30-84 via transmission electron microscopy. Mutants defective in the production of one or both R-tailocins demonstrated that the killing spectrum of each tailocin is limited to Pseudomonas species. The spectra of pseudomonads killed by the two R-tailocins differed, although a few Pseudomonas species were either killed by or insusceptible to both tailocins. Tailocin release was disrupted by deletion of the holin gene within the tailocin gene cluster, demonstrating that the lysis cassette is required for the release of both R-tailocins. The loss of functional tailocin production reduced the ability of P. chlororaphis 30-84 to compete with an R-tailocin-sensitive strain within biofilms and rhizosphere communities. Our study demonstrates that Pseudomonas species can produce more than one functional R-tailocin particle sharing the same lysis cassette but differing in their killing spectra. This study provides evidence for the role of R-tailocins as determinants of bacterial competition among plant-associated Pseudomonas in biofilms and the rhizosphere.IMPORTANCE Recent studies have identified R-tailocin gene clusters potentially encoding more than one R-tailocin within the genomes of plant-associated Pseudomonas but have not demonstrated that more than one particle is produced or the ecological significance of the production of multiple R-tailocins. This study demonstrates for the first time that Pseudomonas strains can produce two distinct R-tailocins with different killing spectra, both of which contribute to bacterial competition between rhizosphere-associated bacteria. These results provide new insight into the previously uncharacterized role of R-tailocin production by plant-associated Pseudomonas species in bacterial population dynamics within surface-attached biofilms and on roots.
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A Broad-Host-Range Tailocin from Burkholderia cenocepacia. Appl Environ Microbiol 2017; 83:AEM.03414-16. [PMID: 28258146 PMCID: PMC5411513 DOI: 10.1128/aem.03414-16] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 02/07/2017] [Indexed: 02/07/2023] Open
Abstract
The Burkholderia cepacia complex (Bcc) consists of 20 closely related Gram-negative bacterial species that are significant pathogens for persons with cystic fibrosis (CF). Some Bcc strains are highly transmissible and resistant to multiple antibiotics, making infection difficult to treat. A tailocin (phage tail-like bacteriocin), designated BceTMilo, with a broad host range against members of the Bcc, was identified in B. cenocepacia strain BC0425. Sixty-eight percent of Bcc representing 10 species and 90% of non-Bcc Burkholderia strains tested were sensitive to BceTMilo. BceTMilo also showed killing activity against Pseudomonas aeruginosa PAO1 and derivatives. Liquid chromatography-mass spectrometry analysis of the major BceTMilo proteins was used to identify a 23-kb tailocin locus in a draft BC0425 genome. The BceTMilo locus was syntenic and highly similar to a 24.6-kb region on chromosome 1 of B. cenocepacia J2315 (BCAL0081 to BCAL0107). A close relationship and synteny were observed between BceTMilo and Burkholderia phage KL3 and, by extension, with paradigm temperate myophage P2. Deletion mutants in the gene cluster encoding enzymes for biosynthesis of lipopolysaccharide (LPS) in the indicator strain B. cenocepacia K56-2 conferred resistance to BceTMilo. Analysis of the defined mutants in LPS biosynthetic genes indicated that an α-d-glucose residue in the core oligosaccharide is the receptor for BceTMilo.IMPORTANCE BceTMilo, presented in this study, is a broad-host-range tailocin active against Burkholderia spp. As such, BceTMilo and related or modified tailocins have potential as bactericidal therapeutic agents against plant- and human-pathogenic Burkholderia.
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Chen F, Chen G, Liu Y, Jin Y, Cheng Z, Liu Y, Yang L, Jin S, Wu W. Pseudomonas aeruginosa Oligoribonuclease Contributes to Tolerance to Ciprofloxacin by Regulating Pyocin Biosynthesis. Antimicrob Agents Chemother 2017; 61:e02256-16. [PMID: 28052848 PMCID: PMC5328516 DOI: 10.1128/aac.02256-16] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2016] [Accepted: 12/21/2016] [Indexed: 01/17/2023] Open
Abstract
Bacterial oligoribonuclease (Orn) is a conserved 3'-to-5' exonuclease. In Pseudomonas aeruginosa, it has been demonstrated that Orn plays a major role in the hydrolysis of pGpG, which is required for cyclic-di-GMP homeostasis. Meanwhile, Orn is involved in the degradation of nanoRNAs, which can alter global gene expression by serving as transcription initiation primers. Previously, we found that Orn is required for the type III secretion system and pathogenesis of P. aeruginosa, indicating a role of Orn in the bacterial response to environmental stimuli. Here we report that Orn is required for the tolerance of P. aeruginosa to ciprofloxacin. Transcriptome analysis of an orn mutant revealed the upregulation of pyocin biosynthesis genes. Mutation of genes involved in pyocin biosynthesis in the background of an orn mutant restored bacterial tolerance to ciprofloxacin. We further demonstrate that the upregulation of pyocin biosynthesis genes is due to RecA-mediated autoproteolysis of PrtR, which is the major negative regulator of pyocin biosynthesis genes. In addition, the SOS response genes were upregulated in the orn mutant, indicating a DNA damage stress. Therefore, our results revealed a novel role of Orn in bacterial tolerance to ciprofloxacin.
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Affiliation(s)
- Fei Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Gukui Chen
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yiwei Liu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yongxin Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Zhihui Cheng
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
| | - Yang Liu
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Division of Structural Biology and Biochemistry, Nanyang Technological University, Singapore, Singapore
| | - Liang Yang
- Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, Singapore, Singapore
- School of Biological Sciences, Division of Structural Biology and Biochemistry, Nanyang Technological University, Singapore, Singapore
| | - Shouguang Jin
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
- Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida, Gainesville, Florida, USA
| | - Weihui Wu
- State Key Laboratory of Medicinal Chemical Biology, Key Laboratory of Molecular Microbiology and Technology of the Ministry of Education, Department of Microbiology, College of Life Sciences, Nankai University, Tianjin, China
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Ghequire MGK, Kemland L, De Mot R. Novel Immunity Proteins Associated with Colicin M-like Bacteriocins Exhibit Promiscuous Protection in Pseudomonas. Front Microbiol 2017; 8:93. [PMID: 28194143 PMCID: PMC5277000 DOI: 10.3389/fmicb.2017.00093] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 01/13/2017] [Indexed: 01/08/2023] Open
Abstract
Bacteriocins related to colicin M, acting via cleavage of the cell wall precursor lipid II, have been characterized in γ- and β-proteobacteria. Depending on the species, immunity is provided by either an inner membrane-anchored periplasmic protein or by an integral membrane protein. In Pseudomonas however, the immunity partner of colicin M-like bacteriocins remains unknown. Based on an in silico analysis in pseudomonad genomes, we here identify a gene encoding a putative immunity partner that represents a novel type of integral membrane protein (PmiA, Pseudomonas colicin M-like immunity type A). By heterologous expression of pmiA genes in susceptible strains, we show that immunity to colicin M-like bacteriocins is indeed provided by the cognate PmiA. Sequence homology among PmiA proteins is essentially absent, except for a short motif with a conserved periplasm-exposed aspartate residue. However, PmiA's protective function is not abolished by changing this acidic residue to the uncharged alanine. Immunity by PmiAs appears promiscuous to the extent that PmiA homologs from a clade sharing <40% pairwise amino acid identity, equally provide protection against the bacteriocin linked to the original PmiA. This study shows that multiple immunity factors have evolved independently to silence lipid II-targeting enzymatic bacteriocins. Their relaxed bacteriocin immunization capacity contrasts to the strict specificity of immunity proteins shielding the enzymatic domain of nuclease bacteriocins. The nature of associated immune functions needs consideration when using such natural protein antibiotics or designing novel variants.
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Affiliation(s)
- Maarten G K Ghequire
- Centre of Microbial and Plant Genetics, KU LeuvenHeverlee, Belgium; National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of HealthBethesda, MD, USA
| | | | - René De Mot
- Centre of Microbial and Plant Genetics, KU Leuven Heverlee, Belgium
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Draft Genome Sequence of Pseudomonas putida BW11M1, a Banana Rhizosphere Isolate with a Diversified Antimicrobial Armamentarium. GENOME ANNOUNCEMENTS 2016; 4:4/2/e00251-16. [PMID: 27081131 PMCID: PMC4832159 DOI: 10.1128/genomea.00251-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In this study, we report the draft genome of Pseudomonas putida BW11M1, a banana rhizosphere isolate producing various antimicrobial compounds, including a lectin-like bacteriocin, an R-type tailocin, the cyclic lipopeptide xantholysin, and the fatty acid–derived pseudopyronine.
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Dingemans J, Ghequire MGK, Craggs M, De Mot R, Cornelis P. Identification and functional analysis of a bacteriocin, pyocin S6, with ribonuclease activity from a Pseudomonas aeruginosa cystic fibrosis clinical isolate. Microbiologyopen 2016; 5:413-23. [PMID: 26860427 PMCID: PMC4905994 DOI: 10.1002/mbo3.339] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Revised: 11/30/2015] [Accepted: 01/05/2016] [Indexed: 01/28/2023] Open
Abstract
S‐type pyocins are bacteriocins produced by Pseudomonas aeruginosa isolates to antagonize or kill other strains of the same species. They have a modular organization comprising a receptor‐binding domain recognizing a surface constituent of the target bacterium, a domain for translocation through the periplasm, and a killing or toxic domain with DNase, tRNase, or pore‐forming activity. Pyocins S2, S3, S4, and S5 recognize TonB‐dependent ferri‐siderophore receptors in the outer membrane. We here describe a new nuclease bacteriocin, pyocin S6, encoded in the genome of a P. aeruginosa cystic fibrosis (CF) clinical isolate, CF_PA39. Similarly to pyocins S1 and S2, the S6 toxin–immunity gene tandem was recruited to the genomic region encoding exotoxin A. The pyocin S6 receptor‐binding and translocation domains are identical to those of pyocin S1, whereas the killing domain is similar to the 16S ribonuclease domain of Escherichia coli colicin E3. The cytotoxic activity was abolished in pyocin S6 forms with a mutation in the colicin E3‐equivalent catalytic motif. The CF_PA39 S6 immunity gene displays a higher expression level than the gene encoding the killing protein, the latter being only detected when bacteria are grown under iron‐limiting conditions. In the S1‐pyocinogenic strain P. aeruginosa ATCC 25324 and pyocin S2 producer P. aeruginosa PAO1, a remnant of the pyocin S6 killing domain and an intact S6‐type immunity gene are located downstream of their respective pyocin operons. Strain PAO1 is insensitive for pyocin S6, and its S6‐type immunity gene provides protection against pyocin S6 activity. Purified pyocin S6 inhibits one‐fifth of 110 P. aeruginosa CF clinical isolates tested, showing clearer inhibition zones when the target cells are grown under iron limitation. In this panel, about half of the CF clinical isolates were found to host the S6 genes. The pyocin S6 locus is also present in the genome of some non‐CF clinical isolates.
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Affiliation(s)
- Jozef Dingemans
- Department of Bioengineering Sciences, Research group Microbiology and VIB Department of Structural Biology, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050, Belgium
| | - Maarten G K Ghequire
- Department Microbial and Molecular Systems, Centre of Microbial and Plant Genetics, KU Leuven Kasteelpark Arenberg 20 - bus 2460, Heverlee, B-3001, Belgium
| | - Michael Craggs
- Department of Bioengineering Sciences, Research group Microbiology and VIB Department of Structural Biology, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050, Belgium
| | - René De Mot
- Department Microbial and Molecular Systems, Centre of Microbial and Plant Genetics, KU Leuven Kasteelpark Arenberg 20 - bus 2460, Heverlee, B-3001, Belgium
| | - Pierre Cornelis
- Department of Bioengineering Sciences, Research group Microbiology and VIB Department of Structural Biology, Vrije Universiteit Brussel, Pleinlaan 2, Brussels, 1050, Belgium
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Distinct colicin M-like bacteriocin-immunity pairs in Burkholderia. Sci Rep 2015; 5:17368. [PMID: 26610609 PMCID: PMC4661593 DOI: 10.1038/srep17368] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 10/28/2015] [Indexed: 11/30/2022] Open
Abstract
The Escherichia coli bacteriocin colicin M (ColM) acts via degradation of the cell wall precursor lipid II in target cells. ColM producers avoid self-inhibition by a periplasmic immunity protein anchored in the inner membrane. In this study, we identified colM-like bacteriocin genes in genomes of several β-proteobacterial strains belonging to the Burkholderia cepacia complex (Bcc) and the Burkholderia pseudomallei group. Two selected Burkholderia ambifaria proteins, designated burkhocins M1 and M2, were produced recombinantly and showed antagonistic activity against Bcc strains. In their considerably sequence-diverged catalytic domain, a conserved aspartate residue equally proved pivotal for cytotoxicity. Immunity to M-type burkhocins is conferred upon susceptible strains by heterologous expression of a cognate gene located either upstream or downstream of the toxin gene. These genes lack homology with currently known ColM immunity genes and encode inner membrane-associated proteins of two distinct types, differing in predicted transmembrane topology and moiety exposed to the periplasm. The addition of burkhocins to the bacteriocin complement of Burkholderia reveals a wider phylogenetic distribution of ColM-like bacteriotoxins, beyond the γ-proteobacterial genera Escherichia, Pectobacterium and Pseudomonas, and illuminates the diversified nature of immunity-providing proteins.
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Bauer JS, Ghequire MGK, Nett M, Josten M, Sahl HG, De Mot R, Gross H. Biosynthetic Origin of the Antibiotic Pseudopyronines A and B in Pseudomonas putida BW11M1. Chembiochem 2015; 16:2491-7. [PMID: 26507104 DOI: 10.1002/cbic.201500413] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Indexed: 11/08/2022]
Abstract
Within the framework of our effort to discover new antibiotics from pseudomonads, pseudopyronines A and B were isolated from the plant-derived Pseudomonas putida BW11M1. Pseudopyronines are 3,6-dialkyl-4-hydroxy-2-pyrones and displayed high in vitro activities against several human pathogens, and in our hands also towards the plant pathogen Pseudomonas savastanoi. Here, the biosynthesis of pseudopyronine B was studied by a combination of feeding experiments with isotopically labeled precursors, genomic sequence analysis, and gene deletion experiments. The studies resulted in the deduction of all acetate units and revealed that the biosynthesis of these α-pyrones occurs with a single PpyS-homologous ketosynthase. It fuses, with some substrate flexibility, a 3-oxo-fatty acid and a further unbranched saturated fatty acid, both of medium chain-length and provided by primary metabolism.
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Affiliation(s)
- Judith S Bauer
- Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany.,German Centre for Infection Research (DZIF), Partner site Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany
| | - Maarten G K Ghequire
- Centre of Microbial and Plant Genetics, Department of Microbial and Molecular Systems, University of Leuven, Kasteelpark Arenberg 20, 3001, Heverlee-Leuven, Belgium
| | - Markus Nett
- Junior Research Group "Secondary Metabolism of Predatory Bacteria", Leibniz Institute for Natural Product Research and Infection Biology, Hans-Knöll-Institut, Beutenbergstrasse 11 A, 07745, Jena, Germany
| | - Michaele Josten
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), Pharmaceutical Microbiology Unit, University of Bonn, Meckenheimer Allee 168, 53115, Bonn, Germany.,German Centre for Infection Research (DZIF), Partner site Bonn-Cologne, Meckenheimer Allee 168, 53115, Bonn, Germany
| | - Hans-Georg Sahl
- Institute for Medical Microbiology, Immunology and Parasitology (IMMIP), Pharmaceutical Microbiology Unit, University of Bonn, Meckenheimer Allee 168, 53115, Bonn, Germany.,German Centre for Infection Research (DZIF), Partner site Bonn-Cologne, Meckenheimer Allee 168, 53115, Bonn, Germany
| | - René De Mot
- Centre of Microbial and Plant Genetics, Department of Microbial and Molecular Systems, University of Leuven, Kasteelpark Arenberg 20, 3001, Heverlee-Leuven, Belgium.
| | - Harald Gross
- Department of Pharmaceutical Biology, Pharmaceutical Institute, University of Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany. .,German Centre for Infection Research (DZIF), Partner site Tübingen, Auf der Morgenstelle 8, 72076, Tübingen, Germany.
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