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Oscarsson J, Bao K, Shiratsuchi A, Grossmann J, Wolski W, Aung KM, Lindholm M, Johansson A, Mowsumi FR, Wai SN, Belibasakis GN, Bostanci N. Bacterial symbionts in oral niche use type VI secretion nanomachinery for fitness increase against pathobionts. iScience 2024; 27:109650. [PMID: 38650989 PMCID: PMC11033201 DOI: 10.1016/j.isci.2024.109650] [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: 12/18/2023] [Revised: 02/09/2024] [Accepted: 03/27/2024] [Indexed: 04/25/2024] Open
Abstract
Microbial ecosystems experience spatial and nutrient restrictions leading to the coevolution of cooperation and competition among cohabiting species. To increase their fitness for survival, bacteria exploit machinery to antagonizing rival species upon close contact. As such, the bacterial type VI secretion system (T6SS) nanomachinery, typically expressed by pathobionts, can transport proteins directly into eukaryotic or prokaryotic cells, consequently killing cohabiting competitors. Here, we demonstrate for the first time that oral symbiont Aggregatibacter aphrophilus possesses a T6SS and can eliminate its close relative oral pathobiont Aggregatibacter actinomycetemcomitans using its T6SS. These findings bring nearer the anti-bacterial prospects of symbionts against cohabiting pathobionts while introducing the presence of an active T6SS in the oral cavity.
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Affiliation(s)
- Jan Oscarsson
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
| | - Kai Bao
- Division of Oral Health and Periodontology, Department of Dental Medicine, Karolinska Institutet, Alfred Nobels Allé 8, 14104 Huddinge, Stockholm, Sweden
| | - Akiko Shiratsuchi
- Department of Liberal Arts and Sciences, Graduate School of Medicine, Sapporo Medical University, Sapporo, Hokkaido 060-8556, Japan
| | - Jonas Grossmann
- Functional Genomics Center Zurich, ETH Zürich and University of Zürich, Zürich, Switzerland
- Swiss Institute of Bioinformatics (SIB) Quartier Sorge-Batiment Amphipole, 1015 Lausanne, Switzerland
| | - Witold Wolski
- Functional Genomics Center Zurich, ETH Zürich and University of Zürich, Zürich, Switzerland
- Swiss Institute of Bioinformatics (SIB) Quartier Sorge-Batiment Amphipole, 1015 Lausanne, Switzerland
| | - Kyaw Min Aung
- Department of Molecular Biology and the Umeå Centre for Microbial Research (UCMR), and the Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 90187 Umeå, Sweden
| | - Mark Lindholm
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
- Division of Oral Health and Periodontology, Department of Dental Medicine, Karolinska Institutet, Alfred Nobels Allé 8, 14104 Huddinge, Stockholm, Sweden
| | - Anders Johansson
- Oral Microbiology, Department of Odontology, Umeå University, Umeå, Sweden
| | | | - Sun Nyunt Wai
- Department of Molecular Biology and the Umeå Centre for Microbial Research (UCMR), and the Laboratory for Molecular Infection Medicine Sweden (MIMS), Umeå University, 90187 Umeå, Sweden
| | - Georgios N. Belibasakis
- Division of Oral Health and Periodontology, Department of Dental Medicine, Karolinska Institutet, Alfred Nobels Allé 8, 14104 Huddinge, Stockholm, Sweden
| | - Nagihan Bostanci
- Division of Oral Health and Periodontology, Department of Dental Medicine, Karolinska Institutet, Alfred Nobels Allé 8, 14104 Huddinge, Stockholm, Sweden
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Ramamoorthy S, Pena M, Ghosh P, Liao YY, Paret M, Jones JB, Potnis N. Transcriptome profiling of type VI secretion system core gene tssM mutant of Xanthomonas perforans highlights regulators controlling diverse functions ranging from virulence to metabolism. Microbiol Spectr 2024; 12:e0285223. [PMID: 38018859 PMCID: PMC10782981 DOI: 10.1128/spectrum.02852-23] [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: 07/14/2023] [Accepted: 10/20/2023] [Indexed: 11/30/2023] Open
Abstract
IMPORTANCE T6SS has received attention due to its significance in mediating interorganismal competition through contact-dependent release of effector molecules into prokaryotic and eukaryotic cells. Reverse-genetic studies have indicated the role of T6SS in virulence in a variety of plant pathogenic bacteria, including the one studied here, Xanthomonas. However, it is not clear whether such effect on virulence is merely due to a shift in the microbiome-mediated protection or if T6SS is involved in a complex virulence regulatory network. In this study, we conducted in vitro transcriptome profiling in minimal medium to decipher the signaling pathways regulated by tssM-i3* in X. perforans AL65. We show that TssM-i3* regulates the expression of a suite of genes associated with virulence and metabolism either directly or indirectly by altering the transcription of several regulators. These findings further expand our knowledge on the intricate molecular circuits regulated by T6SS in phytopathogenic bacteria.
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Affiliation(s)
- Sivakumar Ramamoorthy
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Michelle Pena
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Palash Ghosh
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Ying-Yu Liao
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Mathews Paret
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
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Wu S, Tang J, Wang B, Cai J, Jian J. Roles of Hcp2, a Hallmark of T6SS2 in Motility, Adhesive Capacity, and Pathogenicity of Vibrio alginolyticus. Microorganisms 2023; 11:2893. [PMID: 38138037 PMCID: PMC10745990 DOI: 10.3390/microorganisms11122893] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Revised: 11/28/2023] [Accepted: 11/29/2023] [Indexed: 12/24/2023] Open
Abstract
The type VI secretion system (T6SS) is a large secretory device, widely found in Gram-negative bacteria, which plays important roles in virulence, bacterial competition, and environmental adaptation. Vibrio alginolyticus (V. alginolyticus) is an opportunistic pathogen that causes vibriosis in aquaculture animals. V. alginolyticus possesses two type VI secretion systems (named the T6SS1 and T6SS2), but their functions remain largely unclear. In this paper, the roles of the core component of the T6SS2 cluster of V. alginolyticus HY9901, hemolysin-coregulated protein2 coding gene hcp2, are reported. Deletion of hcp2 clearly impaired the swarming motility, adhesive capacity, and pathogenicity of V. alginolyticus against zebrafish. Furthermore, transmission electron microscopy (TEM) found that the abnormal morphology of flagellum filament in the hcp2 mutant strain could be partially restored by hcp2 complementarity. By proteomic and RT-qPCR analysis, we confirmed that the expression levels of flagellar flagellin and assembly-associated proteins were remarkably decreased in an hcp2 mutant strain, compared with the wild-type strain, and could be partially restored with a supply of hcp2. Accordingly, hcp2 had a positive influence on the transcription of flagellar regulons rpoN, rpoS, and fliA; this was verified by RT-qPCR. Taken together, these results suggested that hcp2 was involved in mediating the motility, adhesion, and pathogenicity of Vibrio alginolyticus through positively impacting its flagellar system.
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Affiliation(s)
- Shuilong Wu
- Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, College of Fishery, Guangdong Ocean University, Zhanjiang 524088, China
- Key Laboratory of Diseases Controlling for Aquatic Economic Animals of Guangdong Higher Education Institutions, College of Fishery, Guangdong Ocean University, Zhanjiang 524088, China
- Central People’s Hospital of Zhanjiang, Zhanjiang 524045, China
| | - Jufen Tang
- Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, College of Fishery, Guangdong Ocean University, Zhanjiang 524088, China
- Key Laboratory of Diseases Controlling for Aquatic Economic Animals of Guangdong Higher Education Institutions, College of Fishery, Guangdong Ocean University, Zhanjiang 524088, China
| | - Bei Wang
- Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, College of Fishery, Guangdong Ocean University, Zhanjiang 524088, China
- Key Laboratory of Diseases Controlling for Aquatic Economic Animals of Guangdong Higher Education Institutions, College of Fishery, Guangdong Ocean University, Zhanjiang 524088, China
| | - Jia Cai
- Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, College of Fishery, Guangdong Ocean University, Zhanjiang 524088, China
- Key Laboratory of Diseases Controlling for Aquatic Economic Animals of Guangdong Higher Education Institutions, College of Fishery, Guangdong Ocean University, Zhanjiang 524088, China
| | - Jichang Jian
- Guangdong Provincial Key Laboratory of Aquatic Animal Disease Control and Healthy Culture, College of Fishery, Guangdong Ocean University, Zhanjiang 524088, China
- Key Laboratory of Diseases Controlling for Aquatic Economic Animals of Guangdong Higher Education Institutions, College of Fishery, Guangdong Ocean University, Zhanjiang 524088, China
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Wang H, Guo Y, Liu Z, Chang Z. The Type VI Secretion System Contributes to the Invasiveness of Liver Abscess Caused by Klebsiella pneumoniae. J Infect Dis 2023; 228:1127-1136. [PMID: 37208895 DOI: 10.1093/infdis/jiad166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 04/25/2023] [Accepted: 05/17/2023] [Indexed: 05/21/2023] Open
Abstract
BACKGROUND Klebsiella pneumoniae liver abscess (KPLA) with extrahepatic migratory infections is defined as invasive KPLA (IKPLA). The type VI secretion system (T6SS) is involved in the pathogenesis of KPLA. We hypothesized that T6SS plays a role in IKPLA. METHODS 16S ribosomal RNA gene sequencing was performed on abscess samples. Polymerase chain reaction (PCR) and reverse-transcription PCR (RT-PCR) was used to validate the expression difference of T6SS hallmark genes. In vitro and in vivo experiments were performed to identify the pathogenic feature of T6SS. RESULTS PICRUSt2 predicted that the T6SS-related genes were notably enriched in the IKPLA group. PCR detection of T6SS hallmark genes (hcp, vgrG, and icmF) showed that 197 (81.1%) were T6SS-positive strains. The T6SS-positive strain detection rate in the IKPLA group was higher than in the KPLA group (97.1% vs 78.4%; P < .05). RT-PCR showed that the hcp expression level was markedly increased in IKPLA isolates (P < .05). The T6SS-positive isolates showed higher survival against serum and neutrophil killing (all P < .05). The T6SS-positive K pneumoniae-infected mice had a shorter survival time, higher mortality, and an increased interleukin 6 expression in the liver and lungs (all P < .05). CONCLUSIONS T6SS is an essential virulence factor for K pneumoniae and contributes to IKPLA.
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Affiliation(s)
- Hairui Wang
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Yawen Guo
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Zhaoyu Liu
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
| | - Zhihui Chang
- Department of Radiology, Shengjing Hospital of China Medical University, Shenyang, China
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Lin Y, Zhao D, Huang N, Liu S, Zheng J, Cao J, Zeng W, Zheng X, Wang L, Zhou T, Sun Y. Clinical impact of the type VI secretion system on clinical characteristics, virulence and prognosis of Acinetobacter baumannii during bloodstream infection. Microb Pathog 2023; 182:106252. [PMID: 37454943 DOI: 10.1016/j.micpath.2023.106252] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 07/11/2023] [Accepted: 07/13/2023] [Indexed: 07/18/2023]
Abstract
The type VI secretion system (T6SS) has been regarded as a late-model virulence factor widely distributed in Acinetobacter baumannii (A. baumannii). This study aimed to elucidate the clinical manifestations, the genetic background and microbiological characteristics of A. baumannii isolates causing bloodstream infection (BSI), and assessed the impact of T6SS carrying state on the clinical course. In this study, Clinical samples of A. baumannii causing BSI were collected from a teaching hospital in China from 2016 to 2020 and a retrospective cohort was conducted. Experimental strains were categorized into T6SS positive and negative groups through PCR targeting on hcp gene. The antimicrobials sensitivity test, virulence genes, biofilm formation ability, serum resistance of A. baumannii strains and Galleria mellonella infection model were investigated. Independent risk factors for T6SS+ A. baumannii BSI and Kaplan-Meier curve through follow-up survey were analyzed. A total of 182 A. baumannii strains were isolated from patients with BSI during 5 years and the medical records of all patients were retrospectively reviewed. The proportion of T6SS+ isolates was 62.64% (114/182), which exhibited significantly higher resistance rates of commonly used antibacterial drugs compared to T6SS- group. We found that T6SS+ A. baumannii strains had significantly weaker biofilm formation ability compared to T6SS- A. baumannii. Despite no difference in the positivity rate of tested virulence genes in two groups, T6SS+ strains exhibited higher resistance to the serum and increased virulence in vivo compared to T6SS- strains, indicating that T6SS is likely to enhance the survival and invasive capabilities of A. baumannii in vivo. Indwelling catheter, respiratory diseases, ICU history, white blood cell count and percentage of neutrophils increasing were independent risk factors for T6SS+ A. baumannii BSI. At last, the Kaplan-Meier curve confirmed a higher mortality rate associated with T6SS+ A. baumannii BSI, suggesting that the presence of T6SS may serve as a prognostic factor for mortality. In conclusion, our study revealed that T6SS+ A. baumannii exhibited distinct clinical features, characterized by high antimicrobial resistance and enhanced virulence, providing valuable insights for clinical treatment considerations.
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Affiliation(s)
- Yishuai Lin
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, People's Republic of China; Department of Blood Transfusion, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Deyi Zhao
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Na Huang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, People's Republic of China
| | - Shixing Liu
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, People's Republic of China
| | - Junyuan Zheng
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, People's Republic of China
| | - Jianming Cao
- Department of Medical Lab Science, School of Laboratory Medicine and Life Science, Wenzhou Medical University, Wenzhou, Zhejiang Province, People's Republic of China
| | - Weiliang Zeng
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, People's Republic of China
| | - Xiangkuo Zheng
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, People's Republic of China
| | - Lingbo Wang
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, People's Republic of China
| | - Tieli Zhou
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, People's Republic of China.
| | - Yao Sun
- Department of Clinical Laboratory, The First Affiliated Hospital of Wenzhou Medical University, Key Laboratory of Clinical Laboratory Diagnosis and Translational Research of Zhejiang Province, Wenzhou, Zhejiang Province, People's Republic of China.
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Hespanhol JT, Nóbrega-Silva L, Bayer-Santos E. Regulation of type VI secretion systems at the transcriptional, posttranscriptional and posttranslational level. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001376. [PMID: 37552221 PMCID: PMC10482370 DOI: 10.1099/mic.0.001376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/25/2023] [Indexed: 08/09/2023]
Abstract
Bacteria live in complex polymicrobial communities and are constantly competing for resources. The type VI secretion system (T6SS) is a widespread antagonistic mechanism used by Gram-negative bacteria to gain an advantage over competitors. T6SSs translocate toxic effector proteins inside target prokaryotic cells in a contact-dependent manner. In addition, some T6SS effectors can be secreted extracellularly and contribute to the scavenging scarce metal ions. Bacteria deploy their T6SSs in different situations, categorizing these systems into offensive, defensive and exploitative. The great variety of bacterial species and environments occupied by such species reflect the complexity of regulatory signals and networks that control the expression and activation of the T6SSs. Such regulation is tightly controlled at the transcriptional, posttranscriptional and posttranslational level by abiotic (e.g. pH, iron) or biotic (e.g. quorum-sensing) cues. In this review, we provide an update on the current knowledge about the regulatory networks that modulate the expression and activity of T6SSs across several species, focusing on systems used for interbacterial competition.
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Affiliation(s)
- Julia Takuno Hespanhol
- Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo 05508-900, Brazil
| | - Luize Nóbrega-Silva
- Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo 05508-900, Brazil
| | - Ethel Bayer-Santos
- Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo 05508-900, Brazil
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Lin YL, Smith SN, Kanso E, Septer AN, Rycroft CH. A subcellular biochemical model for T6SS dynamics reveals winning competitive strategies. PNAS NEXUS 2023; 2:pgad195. [PMID: 37441614 PMCID: PMC10335733 DOI: 10.1093/pnasnexus/pgad195] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/30/2023] [Accepted: 06/01/2023] [Indexed: 07/15/2023]
Abstract
The type VI secretion system (T6SS) is a broadly distributed interbacterial weapon that can be used to eliminate competing bacterial populations. Although unarmed target populations are typically used to study T6SS function in vitro, bacteria most likely encounter other T6SS-armed competitors in nature. However, the connection between subcellular details of the T6SS and the outcomes of such mutually lethal battles is not well understood. Here, we incorporate biological data derived from natural competitors of Vibrio fischeri light organ symbionts to build a biochemical model for T6SS at the single-cell level, which we then integrate into an agent-based model (ABM). Using the ABM, we isolate and experiment with strain-specific physiological differences between competitors in ways not possible with biological samples to identify winning strategies for T6SS-armed populations. Through in vitro experiments, we discover that strain-specific differences exist in T6SS activation speed. ABM simulations corroborate that faster activation is dominant in determining survival during competition. Once competitors are fully activated, the energy required for T6SS creates a tipping point where increased weapon building and firing becomes too costly to be advantageous. Through ABM simulations, we identify the threshold where this transition occurs in the T6SS parameter space. We also find that competitive outcomes depend on the geometry of the battlefield: unarmed target cells survive at the edges of a range expansion where unlimited territory can be claimed. Alternatively, competitions within a confined space, much like the light organ crypts where natural V. fischeri compete, result in the rapid elimination of the unarmed population.
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Affiliation(s)
| | | | - Eva Kanso
- Department of Aerospace and Mechanical Engineering, University of Southern California, 3650 McClintock Ave, Los Angeles, CA 90089, USA
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Proutière A, Drebes Dörr NC, Bader L, Stutzmann S, Metzger LC, Isaac S, Chiaruttini N, Blokesch M. Sporadic type VI secretion in seventh pandemic Vibrio cholerae. MICROBIOLOGY (READING, ENGLAND) 2023; 169. [PMID: 37134007 DOI: 10.1099/mic.0.001329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Vibrio cholerae is a pathogen that causes disease in millions of people every year by colonizing the small intestine and then secreting the potent cholera toxin. How the pathogen overcomes the colonization barrier created by the host's natural microbiota is, however, still not well understood. In this context, the type VI secretion system (T6SS) has gained considerable attention given its ability to mediate interbacterial killing. Interestingly, and in contrast to non-pandemic or environmental V. cholerae isolates, strains that are causing the ongoing cholera pandemic (7PET clade) are considered T6SS-silent under laboratory conditions. Since this idea was recently challenged, we performed a comparative in vitro study on T6SS activity using diverse strains or regulatory mutants. We show that modest T6SS activity is detectable in most of the tested strains under interbacterial competition conditions. The system's activity was also observed through immunodetection of the T6SS tube protein Hcp in culture supernatants, a phenotype that can be masked by the strains' haemagglutinin/protease. We further investigated the low T6SS activity within the bacterial populations by imaging 7PET V. cholerae at the single-cell level. The micrographs showed the production of the machinery in only a small fraction of cells within the population. This sporadic T6SS production was higher at 30 °C than at 37 °C and occurred independently of the known regulators TfoX and TfoY but was dependent on the VxrAB two-component system. Overall, our work provides new insight into the heterogeneity of T6SS production in populations of 7PET V. cholerae strains in vitro and provides a possible explanation of the system's low activity in bulk measurements.
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Affiliation(s)
- Alexis Proutière
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Natália C Drebes Dörr
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Loriane Bader
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sandrine Stutzmann
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Lisa C Metzger
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Sandrine Isaac
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Nicolas Chiaruttini
- Bioimaging and Optics Platform (PT-BIOP), School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Melanie Blokesch
- Laboratory of Molecular Microbiology, Global Health Institute, School of Life Sciences, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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Sun J, Su H, Zhang W, Luo X, Li R, Liu M. Comparative genomics revealed that Vibrio furnissii and Vibrio fluvialis have mutations in genes related to T6SS1 and T6SS2. Arch Microbiol 2023; 205:207. [PMID: 37101014 DOI: 10.1007/s00203-023-03557-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/13/2023] [Accepted: 04/17/2023] [Indexed: 04/28/2023]
Abstract
The type VI secretion system (T6SS) is important for interbacterial competition and virulence in Vibrio species. It is generally agreed that T6SS provides a fitness advantage to Vibrios. Some Vibrio species possess one, while others possess two T6SSs. Even within the same Vibrio species, different strains can harbor a variable number of T6SSs. Such is the case in V. fluvialis, an opportunistic human pathogen, that some V. fluvialis strains do not harbor T6SS1. This study found that Amphritea, Marinomonas, Marinobacterium, Vibrio, Photobacterium, and Oceanospirillum species have genes encoding V. fluvialis T6SS1 homologs. The cladogram of T6SS1 genes suggested that these genes appeared to be horizontally acquired by V. fluvialis, V. furnissii, and some other Vibrio species, when compared with the species tree. Codon insertions, codon deletions, nonsense mutations, and the insertion sequence are found in many genes, such as clpV1, tssL1, and tssF1, which encode structure components of T6SS1 in V. furnissii and V. fluvialis. Codon deletion events are more common than codon insertion, insertion sequence disruption, and nonsense mutation events in genes that encode components of T6SS1. Similarly, codon insertions and codon deletions are found in genes relevant to T6SS2, including tssM2, vgrG2 and vasH, in V. furnissii and V. fluvialis. These mutations are likely to disable the functions of T6SSs. Our findings indicate that T6SS may have a fitness disadvantage in V. furnissii and V. fluvialis, and the loss of function in T6SS may help these Vibrio species to survive under certain conditions.
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Affiliation(s)
- Jiakai Sun
- College of Oceanography, Hohai University, Nanjing, China
| | - Haochen Su
- College of Oceanography, Hohai University, Nanjing, China
| | - Wenhui Zhang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu Province, China
| | - Xuesong Luo
- State Key Laboratory of Agricultural Microbiology, College of Resources of Environment, Huazhong Agricultural University, Wuhan, China
| | - Ruichao Li
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China.
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu Province, China.
| | - Ming Liu
- Department of Clinical Laboratory, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, 518055, Guangdong Province, P. R. China.
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Septer AN, Sharpe G, Shook EA. The Vibrio fischeri type VI secretion system incurs a fitness cost under host-like conditions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.07.529561. [PMID: 36945377 PMCID: PMC10028907 DOI: 10.1101/2023.03.07.529561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
The type VI secretion system (T6SS) is an interbacterial weapon composed of thousands of protein subunits and predicted to require significant cellular energy to deploy, yet a fitness cost from T6SS use is rarely observed. Here, we identify host-like conditions where the T6SS incurs a fitness cost using the beneficial symbiont, Vibrio fischeri, which uses its T6SS to eliminate competitors in the natural squid host. We hypothesized that a fitness cost for the T6SS could be dependent on the cellular energetic state and used theoretical ATP cost estimates to predict when a T6SS-dependent fitness cost may be apparent. Theoretical energetic cost estimates predicted a minor relative cost for T6SS use in fast-growing populations (0.4-0.45% of total ATP used cell-1), and a higher relative cost (3.1-13.6%) for stationary phase cells. Consistent with these predictions, we observed no significant T6SS-dependent fitness cost for fast-growing populations typically used for competition assays. However, the stationary phase cell density was significantly lower in the wild-type strain, compared to a regulator mutant that does not express the T6SS, and this T6SS-dependent fitness cost was between 11 and 23%. Such a fitness cost could influence the prevalence and biogeography of T6SSs in animal-associated bacteria. While the T6SS may be required in kill or be killed scenarios, once the competitor is eliminated there is no longer selective pressure to maintain the weapon. Our findings indicate an evolved genotype lacking the T6SS would have a growth advantage over its parent, resulting in the eventual dominance of the unarmed population.
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Affiliation(s)
- Alecia N. Septer
- Department of Earth, Marine & Environmental Sciences, University of North Carolina, Chapel Hill, NC 27599
| | - Garrett Sharpe
- Department of Earth, Marine & Environmental Sciences, University of North Carolina, Chapel Hill, NC 27599
- Environment, Ecology & Energy Program, University of North Carolina, Chapel Hill, NC 27599
| | - Erika A. Shook
- Department of Earth, Marine & Environmental Sciences, University of North Carolina, Chapel Hill, NC 27599
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Type VI Secretion Systems: Environmental and Intra-host Competition of Vibrio cholerae. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1404:41-63. [PMID: 36792870 DOI: 10.1007/978-3-031-22997-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The Vibrio Type VI Secretion System (T6SS) is a harpoon-like nanomachine that serves as a defense system and is encoded by approximately 25% of all gram-negative bacteria. In this chapter, we describe the structure of the T6SS in different Vibrio species and outline how the use of different T6SS effector and immunity proteins control kin selection. We summarize the genetic loci that encode the structural elements that make up the Vibrio T6SSs and how these gene clusters are regulated. Finally, we provide insights into T6SS-based competitive dynamics, the role of T6SS genetic exchange in those competitive dynamics, and roles for the Vibrio T6SS in virulence.
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Environmental Reservoirs of Pathogenic Vibrio spp. and Their Role in Disease: The List Keeps Expanding. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1404:99-126. [PMID: 36792873 DOI: 10.1007/978-3-031-22997-8_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
Vibrio species are natural inhabitants of aquatic environments and have complex interactions with the environment that drive the evolution of traits contributing to their survival. These traits may also contribute to their ability to invade or colonize animal and human hosts. In this review, we attempt to summarize the relationships of Vibrio spp. with other organisms in the aquatic environment and discuss how these interactions could potentially impact colonization of animal and human hosts.
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Guckes KR, Miyashiro TI. The type-VI secretion system of the beneficial symbiont Vibrio fischeri. MICROBIOLOGY (READING, ENGLAND) 2023; 169:10.1099/mic.0.001302. [PMID: 36809081 PMCID: PMC9972734 DOI: 10.1099/mic.0.001302] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/23/2023]
Abstract
The mutualistic symbiosis between the Hawaiian bobtail squid Euprymna scolopes and the marine bacterium Vibrio fischeri is a powerful experimental system for determining how intercellular interactions impact animal-bacterial associations. In nature, this symbiosis features multiple strains of V. fischeri within each adult animal, which indicates that different strains initially colonize each squid. Various studies have demonstrated that certain strains of V. fischeri possess a type-VI secretion system (T6SS), which can inhibit other strains from establishing symbiosis within the same host habitat. The T6SS is a bacterial melee weapon that enables a cell to kill adjacent cells by translocating toxic effectors via a lancet-like apparatus. This review describes the progress that has been made in understanding the factors that govern the structure and expression of the T6SS in V. fischeri and its effect on the symbiosis.
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Zhang Y, Huang Y, Ding H, Ma J, Tong X, Zhang Y, Tao Z, Wang Q. A σE-mediated temperature gauge orchestrates type VI secretion system, biofilm formation and cell invasion in pathogen Pseudomonas plecoglossicida. Microbiol Res 2023; 266:127220. [DOI: 10.1016/j.micres.2022.127220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 09/30/2022] [Accepted: 10/03/2022] [Indexed: 11/07/2022]
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Cai H, Yu J, Qiao Y, Ma Y, Zheng J, Lin M, Yan Q, Huang L. Effect of the Type VI Secretion System Secreted Protein Hcp on the Virulence of Aeromonas salmonicida. Microorganisms 2022; 10:microorganisms10122307. [PMID: 36557560 PMCID: PMC9784854 DOI: 10.3390/microorganisms10122307] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 11/16/2022] [Accepted: 11/19/2022] [Indexed: 11/23/2022] Open
Abstract
Aeromonas salmonicida, a psychrophilic bacterial pathogen, is widely distributed in marine freshwater, causing serious economic losses to major salmon farming areas in the world. At present, it is still one of the most important pathogens threatening salmon farming. Hcp (haemolysin-coregulated protein) is an effector protein in the type-VI secretion system (T6SS), which is secreted by T6SS and functions as its structural component. The results of our previous genomic sequencing showed that hcp existed in the mesophilic A. salmonicida SRW-OG1 isolated from naturally infected Epinephelus coioides. To further explore the role of Hcp in A. salmonicida SRW-OG1, we constructed an hcp-RNAi strain and verified its effect on the virulence of A. salmonicida. The results showed that compared with the wild strain, the hcp-RNAi strain suffered from different degrees of decreased adhesion, growth, biofilm formation, extracellular product secretion, and virulence. It was suggested that hcp may be an important virulence gene of A. salmonicida SRW-OG1.
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Affiliation(s)
- Hongyan Cai
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
| | - Jiaying Yu
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
| | - Ying Qiao
- Fourth Institute of Oceanography, Ministry of Natural Resources, No. 26, New Century Avenue, Beihai 536000, China
| | - Ying Ma
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
| | - Jiang Zheng
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
| | - Mao Lin
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
| | - Qingpi Yan
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
- Correspondence: (Q.Y.); (L.H.)
| | - Lixing Huang
- Key Laboratory of Healthy Mariculture for the East China Sea, Fisheries College, Ministry of Agriculture, Jimei University, Xiamen 361021, China
- Correspondence: (Q.Y.); (L.H.)
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Ng SL, Kammann S, Steinbach G, Hoffmann T, Yunker PJ, Hammer BK. Evolution of a cis-Acting SNP That Controls Type VI Secretion in Vibrio cholerae. mBio 2022; 13:e0042222. [PMID: 35604123 PMCID: PMC9239110 DOI: 10.1128/mbio.00422-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Accepted: 04/29/2022] [Indexed: 11/20/2022] Open
Abstract
Mutations in regulatory mechanisms that control gene expression contribute to phenotypic diversity and thus facilitate the adaptation of microbes and other organisms to new niches. Comparative genomics can be used to infer rewiring of regulatory architecture based on large effect mutations like loss or acquisition of transcription factors but may be insufficient to identify small changes in noncoding, intergenic DNA sequence of regulatory elements that drive phenotypic divergence. In human-derived Vibrio cholerae, the response to distinct chemical cues triggers production of multiple transcription factors that can regulate the type VI secretion system (T6), a broadly distributed weapon for interbacterial competition. However, to date, the signaling network remains poorly understood because no regulatory element has been identified for the major T6 locus. Here we identify a conserved cis-acting single nucleotide polymorphism (SNP) controlling T6 transcription and activity. Sequence alignment of the T6 regulatory region from diverse V. cholerae strains revealed conservation of the SNP that we rewired to interconvert V. cholerae T6 activity between chitin-inducible and constitutive states. This study supports a model of pathogen evolution through a noncoding cis-regulatory mutation and preexisting, active transcription factors that confers a different fitness advantage to tightly regulated strains inside a human host and unfettered strains adapted to environmental niches. IMPORTANCE Organisms sense external cues with regulatory circuits that trigger the production of transcription factors, which bind specific DNA sequences at promoters ("cis" regulatory elements) to activate target genes. Mutations of transcription factors or their regulatory elements create phenotypic diversity, allowing exploitation of new niches. Waterborne pathogen Vibrio cholerae encodes the type VI secretion system "nanoweapon" to kill competitor cells when activated. Despite identification of several transcription factors, no regulatory element has been identified in the promoter of the major type VI locus, to date. Combining phenotypic, genetic, and genomic analysis of diverse V. cholerae strains, we discovered a single nucleotide polymorphism in the type VI promoter that switches its killing activity between a constitutive state beneficial outside hosts and an inducible state for constraint in a host. Our results support a role for noncoding DNA in adaptation of this pathogen.
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Affiliation(s)
- Siu Lung Ng
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Diseases and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Sophia Kammann
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Diseases and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Gabi Steinbach
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Diseases and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Tobias Hoffmann
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Peter J. Yunker
- School of Physics, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Diseases and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
| | - Brian K. Hammer
- School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA
- Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, Atlanta, Georgia, USA
- Center for Microbial Diseases and Infection, Georgia Institute of Technology, Atlanta, Georgia, USA
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Zhang Y, Xu Y, Huang Y. Virulence Genotype and Correlation of Clinical Severeness with Presence of the Type VI Secretion System in Klebsiella pneumoniae Isolates Causing Bloodstream Infections. Infect Drug Resist 2022; 15:1487-1497. [PMID: 35411154 PMCID: PMC8994602 DOI: 10.2147/idr.s353858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Accepted: 03/26/2022] [Indexed: 11/23/2022] Open
Abstract
Background Klebsiella pneumoniae (K. pneumoniae) causes bloodstream infection (BSI), which is responsible for a high rate of morbidity and mortality among different populations. In mainland China, data on the correlation and features of the type VI secretion system (T6SS) gene cluster in K. pneumoniae is currently scarce. As a result, we conducted a prospective investigation to determine the involvement of the T6SS in K. pneumoniae pathogenicity and antibiotic resistance. Methods In this prospective analysis, we enrolled 119 individuals who had been diagnosed with K. pneumoniae bloodstream infection between July 2019 and January 2021 and acquired demographic and clinical data from their medical records. The virulence genes rmpA, rmpA2, aerobactin, iroB, hcp, vgrG, and icmF were tested for K1 and K2, antimicrobial susceptibility. Five T6SS-positive and five T6SS-negative isolates were chosen for the competition, serum resistance, and biofilm formation experiments to further gain insights regarding the microbiological properties of T6SS-positive K. pneumoniae isolates. Results Among 119 isolates obtained from patients with BSIs, 20 (16.8%) were T6SS positive K. pneumoniae. T6SS positive strains had four virulence genes and a greater K1 capsular serotypes rate than T6SS negative bacteria. Among hvKP isolates, the T6SS positive rate was substantially greater than the T6SS negative rate (P = 0.001). T6SS-positive K. pneumoniae strains had a lower rate of antimicrobial resistance in comparison to T6SS-negative bacteria. T6SS-positive isolates may be more competitive with Escherichia coli than T6SS-negative isolates. T6SS-positive isolates, on the other hand, did not show stronger biofilm-forming activity or a higher survival rate in the presence of normal human serum in comparison to T6SS-negative isolates. Conclusion T6SS-positive K. pneumoniae was common in people who had BSIs. In T6SS‐containing K. pneumoniae, the system may play a major role in bacterial competition.
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Affiliation(s)
- Yin Zhang
- Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
| | - Yuanhong Xu
- Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
| | - Ying Huang
- Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China
- Correspondence: Ying Huang; Yuanhong Xu, Department of Clinical Laboratory, The First Affiliated Hospital of Anhui Medical University, Hefei, People’s Republic of China, Email ;
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Allsopp LP, Collins ACZ, Hawkins E, Wood TE, Filloux A. RpoN/Sfa2-dependent activation of the Pseudomonas aeruginosa H2-T6SS and its cognate arsenal of antibacterial toxins. Nucleic Acids Res 2021; 50:227-243. [PMID: 34928327 PMCID: PMC8855297 DOI: 10.1093/nar/gkab1254] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 11/26/2021] [Accepted: 12/16/2021] [Indexed: 12/13/2022] Open
Abstract
Pseudomonas aeruginosa uses three type six secretion systems
(H1-, H2- and H3-T6SS) to manipulate its environment, subvert host cells and for
microbial competition. These T6SS machines are loaded with a variety of
effectors/toxins, many being associated with a specific VgrG. How P.
aeruginosa transcriptionally coordinates the main T6SS clusters and
the multiple vgrG islands spread through the genome is unknown.
Here we show an unprecedented level of control with RsmA repressing most known
T6SS-related genes. Moreover, each of the H2- and H3-T6SS clusters encodes a
sigma factor activator (SFA) protein
called, Sfa2 and Sfa3, respectively. SFA proteins are enhancer binding proteins
necessary for the sigma factor RpoN. Using a combination of RNA-seq, ChIP-seq
and molecular biology approaches, we demonstrate that RpoN coordinates the T6SSs
of P. aeruginosa by activating the H2-T6SS but repressing the
H1- and H3-T6SS. Furthermore, RpoN and Sfa2 control the expression of the
H2-T6SS-linked VgrGs and their effector arsenal to enable very effective
interbacterial killing. Sfa2 is specific as Sfa3 from the H3-T6SS cannot
complement loss of Sfa2. Our study further delineates the regulatory mechanisms
that modulate the deployment of an arsenal of T6SS effectors likely enabling
P. aeruginosa to adapt to a range of environmental
conditions.
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Affiliation(s)
- Luke P Allsopp
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK.,National Heart and Lung Institute, Imperial College London, London, UK
| | - Alice C Z Collins
- National Heart and Lung Institute, Imperial College London, London, UK
| | - Eleanor Hawkins
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Thomas E Wood
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
| | - Alain Filloux
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Imperial College London, London, UK
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