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Kumari K, Dey J, Mahapatra SR, Ma Y, Sharma PK, Misra N, Singh RP. Protein profiling and immunoinformatic analysis of the secretome of a metal-resistant environmental isolate Pseudomonas aeruginosa S-8. Folia Microbiol (Praha) 2024:10.1007/s12223-024-01152-5. [PMID: 38457114 DOI: 10.1007/s12223-024-01152-5] [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: 06/14/2023] [Accepted: 02/03/2024] [Indexed: 03/09/2024]
Abstract
The bacterial secretome represents a comprehensive catalog of proteins released extracellularly that have multiple important roles in virulence and intercellular communication. This study aimed to characterize the secretome of an environmental isolate Pseudomonas aeruginosa S-8 by analyzing trypsin-digested culture supernatant proteins using nano-LC-MS/MS tool. Using a combined approach of bioinformatics and mass spectrometry, 1088 proteins in the secretome were analyzed by PREDLIPO, SecretomeP 2.0, SignalP 4.1, and PSORTb tool for their subcellular localization and further categorization of secretome proteins according to signal peptides. Using the gene ontology tool, secretome proteins were categorized into different functional categories. KEGG pathway analysis identified the secreted proteins into different metabolic functional pathways. Moreover, our LC-MS/MS data revealed the secretion of various CAZymes into the extracellular milieu, which suggests its strong biotechnological applications to breakdown complex carbohydrate polymers. The identified immunodominant epitopes from the secretome of P. aeruginosa showed the characteristic of being non-allergenic, highly antigenic, nontoxic, and having a low risk of triggering autoimmune responses, which highlights their potential as successful vaccine targets. Overall, the identification of secreted proteins of P. aeruginosa could be important for both diagnostic purposes and the development of an effective candidate vaccine.
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Affiliation(s)
- Kiran Kumari
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Ranchi, 835215, India
| | - Jyotirmayee Dey
- School of Biotechnology, Deemed to Be University, Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, 751024, India
| | - Soumya Ranjan Mahapatra
- School of Biotechnology, Deemed to Be University, Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, 751024, India
| | - Ying Ma
- College of Resources and Environment, Southwest University, Chongqing, China
| | - Parva Kumar Sharma
- Department of Plant Sciences and Landscape Architecture, University of Maryland, College Park, MD, 20742, USA
| | - Namrata Misra
- School of Biotechnology, Deemed to Be University, Kalinga Institute of Industrial Technology (KIIT), Bhubaneswar, 751024, India
| | - Rajnish Prakash Singh
- Department of Biotechnology, Jaypee Institute of Information Technology, Noida, 201309, India.
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2
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Zhao X, Gao L, Ali Q, Yu C, Yuan B, Huang H, Long J, Gu Q, Wu H, Gao X. A type VI secretion system effector TseG of Pantoea ananatis is involved in virulence and antibacterial activity. MOLECULAR PLANT PATHOLOGY 2024; 25:e13442. [PMID: 38476100 DOI: 10.1111/mpp.13442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 01/14/2024] [Accepted: 02/16/2024] [Indexed: 03/14/2024]
Abstract
The type VI secretion system (T6SS) of many gram-negative bacteria injects toxic effectors into adjacent cells to manipulate host cells during pathogenesis or to kill competing bacteria. However, the identification and function of the T6SS effectors remains only partly known. Pantoea ananatis, a gram-negative bacterium, is commonly found in various plants and natural environments, including water and soil. In the current study, genomic analysis of P. ananatis DZ-12 causing brown stalk rot on maize demonstrated that it carries three T6SS gene clusters, namely, T6SS-1, T6SS-2, and T6SS-3. Interestingly, only T6SS-1 secretion systems are involved in pathogenicity and bacterial competition. The study also investigated the T6SS-1 system in detail and identified an unknown T6SS-1-secreted effector TseG by using the upstream T6SS effector chaperone TecG containing a conserved domain of DUF2169. TseG can directly interact with the chaperone TecG for delivery and with a downstream immunity protein TsiG for protection from its toxicity. TseG, highly conserved in the Pantoea genus, is involved in virulence in maize, potato, and onion. Additionally, P. ananatis uses TseG to target Escherichia coli, gaining a competitive advantage. This study provides the first report on the T6SS-1-secreted effector from P. ananatis, thereby enriching our understanding of the various types and functions of type VI effector proteins.
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Affiliation(s)
- Xiaozhen Zhao
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Lu Gao
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Qurban Ali
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Chenjie Yu
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Bingqin Yuan
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Hai Huang
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Juying Long
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Qin Gu
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Huijun Wu
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Xuewen Gao
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
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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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Durán D, Vazquez-Arias D, Blanco-Romero E, Garrido-Sanz D, Redondo-Nieto M, Rivilla R, Martín M. An Orphan VrgG Auxiliary Module Related to the Type VI Secretion Systems from Pseudomonas ogarae F113 Mediates Bacterial Killing. Genes (Basel) 2023; 14:1979. [PMID: 38002922 PMCID: PMC10671463 DOI: 10.3390/genes14111979] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 10/17/2023] [Accepted: 10/20/2023] [Indexed: 11/26/2023] Open
Abstract
The model rhizobacterium Pseudomonas ogarae F113, a relevant plant growth-promoting bacterium, encodes three different Type VI secretion systems (T6SS) in its genome. In silico analysis of its genome revealed the presence of a genetic auxiliary module containing a gene encoding an orphan VgrG protein (VgrG5a) that is not genetically linked to any T6SS structural cluster, but is associated with genes encoding putative T6SS-related proteins: a possible adaptor Tap protein, followed by a putative effector, Tfe8, and its putative cognate immunity protein, Tfi8. The bioinformatic analysis of the VgrG5a auxiliary module has revealed that this cluster is only present in several subgroups of the P. fluorescens complex of species. An analysis of the mutants affecting the vgrG5a and tfe8 genes has shown that the module is involved in bacterial killing. To test whether Tfe8/Tfi8 constitute an effector-immunity pair, the genes encoding Tfe8 and Tfi8 were cloned and expressed in E. coli, showing that the ectopic expression of tfe8 affected growth. The growth defect was suppressed by tfi8 ectopic expression. These results indicate that Tfe8 is a bacterial killing effector, while Tfi8 is its cognate immunity protein. The Tfe8 protein sequence presents homology to the proteins of the MATE family involved in drug extrusion. The Tfe8 effector is a membrane protein with 10 to 12 transmembrane domains that could destabilize the membranes of target cells by the formation of pores, revealing the importance of these effectors for bacterial interaction. Tfe8 represents a novel type of a T6SS effector present in pseudomonads.
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Affiliation(s)
- David Durán
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049 Madrid, Spain; (D.D.); (D.V.-A.); (E.B.-R.); (D.G.-S.); (M.R.-N.); (R.R.)
| | - David Vazquez-Arias
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049 Madrid, Spain; (D.D.); (D.V.-A.); (E.B.-R.); (D.G.-S.); (M.R.-N.); (R.R.)
| | - Esther Blanco-Romero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049 Madrid, Spain; (D.D.); (D.V.-A.); (E.B.-R.); (D.G.-S.); (M.R.-N.); (R.R.)
| | - Daniel Garrido-Sanz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049 Madrid, Spain; (D.D.); (D.V.-A.); (E.B.-R.); (D.G.-S.); (M.R.-N.); (R.R.)
- Department of Fundamental Microbiology, University of Lausanne, 1015 Lausanne, Switzerland
| | - Miguel Redondo-Nieto
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049 Madrid, Spain; (D.D.); (D.V.-A.); (E.B.-R.); (D.G.-S.); (M.R.-N.); (R.R.)
| | - Rafael Rivilla
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049 Madrid, Spain; (D.D.); (D.V.-A.); (E.B.-R.); (D.G.-S.); (M.R.-N.); (R.R.)
| | - Marta Martín
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049 Madrid, Spain; (D.D.); (D.V.-A.); (E.B.-R.); (D.G.-S.); (M.R.-N.); (R.R.)
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5
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Weisberg AJ, Wu Y, Chang JH, Lai EM, Kuo CH. Virulence and Ecology of Agrobacteria in the Context of Evolutionary Genomics. ANNUAL REVIEW OF PHYTOPATHOLOGY 2023; 61:1-23. [PMID: 37164023 DOI: 10.1146/annurev-phyto-021622-125009] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Among plant-associated bacteria, agrobacteria occupy a special place. These bacteria are feared in the field as agricultural pathogens. They cause abnormal growth deformations and significant economic damage to a broad range of plant species. However, these bacteria are revered in the laboratory as models and tools. They are studied to discover and understand basic biological phenomena and used in fundamental plant research and biotechnology. Agrobacterial pathogenicity and capability for transformation are one and the same and rely on functions encoded largely on their oncogenic plasmids. Here, we synthesize a substantial body of elegant work that elucidated agrobacterial virulence mechanisms and described their ecology. We review findings in the context of the natural diversity that has been recently unveiled for agrobacteria and emphasize their genomics and plasmids. We also identify areas of research that can capitalize on recent findings to further transform our understanding of agrobacterial virulence and ecology.
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Affiliation(s)
- Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA;
| | - Yu Wu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan;
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA;
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan;
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan;
- Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan
- Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
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6
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Brown PJB, Chang JH, Fuqua C. Agrobacterium tumefaciens: a Transformative Agent for Fundamental Insights into Host-Microbe Interactions, Genome Biology, Chemical Signaling, and Cell Biology. J Bacteriol 2023; 205:e0000523. [PMID: 36892285 PMCID: PMC10127608 DOI: 10.1128/jb.00005-23] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/10/2023] Open
Abstract
Agrobacterium tumefaciens incites the formation of readily visible macroscopic structures known as crown galls on plant tissues that it infects. Records from biologists as early as the 17th century noted these unusual plant growths and began examining the basis for their formation. These studies eventually led to isolation of the infectious agent, A. tumefaciens, and decades of study revealed the remarkable mechanisms by which A. tumefaciens causes crown gall through stable horizontal genetic transfer to plants. This fundamental discovery generated a barrage of applications in the genetic manipulation of plants that is still under way. As a consequence of the intense study of A. tumefaciens and its role in plant disease, this pathogen was developed as a model for the study of critical processes that are shared by many bacteria, including host perception during pathogenesis, DNA transfer and toxin secretion, bacterial cell-cell communication, plasmid biology, and more recently, asymmetric cell biology and composite genome coordination and evolution. As such, studies of A. tumefaciens have had an outsized impact on diverse areas within microbiology and plant biology that extend far beyond its remarkable agricultural applications. In this review, we attempt to highlight the colorful history of A. tumefaciens as a study system, as well as current areas that are actively demonstrating its value and utility as a model microorganism.
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Affiliation(s)
- Pamela J. B. Brown
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
| | - Jeff H. Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Clay Fuqua
- Department of Biology, Indiana University, Bloomington, Indiana, USA
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7
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Soil Inoculation and Blocker-Mediated Sequencing Show Effects of the Antibacterial T6SS on Agrobacterial Tumorigenesis and Gallobiome. mBio 2023; 14:e0017723. [PMID: 36877054 PMCID: PMC10128044 DOI: 10.1128/mbio.00177-23] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023] Open
Abstract
The type VI secretion system (T6SS) is deployed by many proteobacteria to secrete effector proteins into bacterial competitors for competition or eukaryotic cells for pathogenesis. Agrobacteria, a group of soilborne phytopathogens causing crown gall disease on various plant species, deploy the T6SS to attack closely and distantly related bacterial species in vitro and in planta. Current evidence suggests that the T6SS is not essential for pathogenesis under direct inoculation, but it remains unknown whether the T6SS influences natural disease incidence or the microbial community within crown galls (i.e., the gallobiome). To address these two key questions, we established a soil inoculation method on wounded tomato seedlings that mimics natural infections and developed a bacterial 16S rRNA gene amplicon enrichment sequencing platform. By comparing the Agrobacterium wild-type strain C58 with two T6SS mutants, we demonstrate that the T6SS influences both disease occurrence and gallobiome composition. Based on multiple inoculation trials across seasons, all three strains induced tumors, but the mutants had significantly lower disease incidences. The season of inoculation played a more important role than the T6SS in shaping the gallobiome. The influence of the T6SS was evident in summer, during which two Sphingomonadaceae species and the family Burkholderiaceae were enriched in the gallobiome induced by the mutants. Further in vitro competition and colonization assays demonstrated the T6SS-mediated antagonism to a Sphingomonas sp. R1 strain isolated from tomato rhizosphere in this study. In conclusion, this work demonstrates that the Agrobacterium T6SS promotes tumorigenesis in infection processes and provides competitive advantages in gall-associated microbiota. IMPORTANCE The T6SS is widespread among proteobacteria and used for interbacterial competition by agrobacteria, which are soil inhabitants and opportunistic bacterial pathogens causing crown gall disease in a wide range of plants. Current evidence indicates that the T6SS is not required for gall formation when agrobacteria are inoculated directly on plant wounding sites. However, in natural settings, agrobacteria may need to compete with other bacteria in bulk soil to gain access to plant wounds and influence the microbial community inside crown galls. The role of the T6SS in these critical aspects of disease ecology have remained largely unknown. In this study, we successfully developed a soil inoculation method coupled with blocker-mediated enrichment of bacterial 16S rRNA gene amplicon sequencing, named SI-BBacSeq, to address these two important questions. We provided evidence that the T6SS promotes disease occurrence and influences crown gall microbiota composition by interbacterial competition.
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8
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Singh RP, Kumari K. Bacterial type VI secretion system (T6SS): an evolved molecular weapon with diverse functionality. Biotechnol Lett 2023; 45:309-331. [PMID: 36683130 DOI: 10.1007/s10529-023-03354-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 12/14/2022] [Accepted: 01/05/2023] [Indexed: 01/24/2023]
Abstract
Bacterial secretion systems are nanomolecular complexes that release a diverse set of virulence factors/or proteins into its surrounding or translocate to their target host cells. Among these systems, type VI secretion system 'T6SS' is a recently discovered molecular secretion system which is widely distributed in Gram-negative (-ve) bacteria, and shares structural similarity with the puncturing device of bacteriophages. The presence of T6SS is an advantage to many bacteria as it delivers toxins to its neighbour pathogens for competitive survival, and also translocates protein effectors to the host cells, leading to disruption of lipid membranes, cell walls, and cytoskeletons etc. Recent studies have characterized both anti-prokaryotic and anti-eukaryotic effectors, where T6SS is involved in diverse cellular functions including favouring colonization, enhancing the survival, adhesive modifications, internalization, and evasion of the immune system. With the evolution of advanced genomics and proteomics tools, there has been an increase in the number of characterized T6SS effector arsenals and also more clear information about the adaptive significance of this complex system. The functions of T6SS are generally regulated at the transcription, post-transcription and post-translational levels through diverse mechanisms. In the present review, we aimed to provide information about the distribution of T6SS in diverse bacteria, any structural similarity/or dissimilarity, effectors proteins, functional significance, and regulatory mechanisms. We also tried to provide information about the diverse roles played by T6SS in its natural environments and hosts, and further any changes in the microbiome.
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Affiliation(s)
- Rajnish Prakash Singh
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India.
| | - Kiran Kumari
- Department of Bioengineering and Biotechnology, Birla Institute of Technology, Mesra, Ranchi, Jharkhand, 835215, India
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9
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Heterologous Assembly of the Type VI Secretion System Empowers Laboratory Escherichia coli with Antimicrobial and Cell Penetration Capabilities. Appl Environ Microbiol 2022; 88:e0130522. [PMID: 36154120 DOI: 10.1128/aem.01305-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The synthetic biology toolbox has amassed a vast number of diverse functional modules, but protein translocation modules for cell penetration and cytosol-to-cytosol delivery remain relatively scarce. The type VI secretion system (T6SS), commonly found in many Gram-negative pathogens, functions as a contractile device to translocate protein toxins to prokaryotic and eukaryotic cells. Here, we have assembled the T6SS of Aeromonas dhakensis, an opportunistic waterborne pathogen, in the common laboratory strain Escherichia coli BL21(DE3). We constructed a series of plasmids (pT6S) carrying the T6SS structural and effector genes under native or tetracycline-inducible promoters, the latter for controlled expression. Using fluorescence microscopy and biochemical analyses, we demonstrate a functional T6SS in E. coli capable of secreting proteins directly into the cytosol of neighboring bacteria and outcompeting a number of drug-resistant pathogens. The heterologous assembly of T6SS not only confers the lab workhorse E. coli with the cytosol-to-cytosol protein delivery capability but also demonstrates the potential for harnessing the T6SS of various pathogens for general protein delivery and antibacterial applications. IMPORTANCE The T6SS is a powerful and versatile protein delivery system. However, the complexity of its macromolecular structure and gene regulation makes it not a trivial task to reconstitute the T6SSs of pathogens in a nonpathogenic host. In this study, we have assembled an inducible T6SS in E. coli BL21(DE3) and demonstrated its functions in protein delivery and antimicrobial activities. The engineered T6SS empowers E. coli to deliver protein cargos into a wide range of prokaryotic and eukaryotic cells.
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10
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Suria AM, Smith S, Speare L, Chen Y, Chien I, Clark EG, Krueger M, Warwick AM, Wilkins H, Septer AN. Prevalence and diversity of type VI secretion systems in a model beneficial symbiosis. Front Microbiol 2022; 13:988044. [PMID: 36187973 PMCID: PMC9515649 DOI: 10.3389/fmicb.2022.988044] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Abstract
The type VI secretion system (T6SS) is widely distributed in diverse bacterial species and habitats where it is required for interbacterial competition and interactions with eukaryotic cells. Previous work described the role of a T6SS in the beneficial symbiont, Vibrio fischeri, during colonization of the light organ of Euprymna scolopes squid. However, the prevalence and diversity of T6SSs found within the distinct symbiotic structures of this model host have not yet been determined. Here, we analyzed 73 genomes of isolates from squid light organs and accessory nidamental glands (ANGs) and 178 reference genomes. We found that the majority of these bacterial symbionts encode diverse T6SSs from four distinct classes, and most share homology with T6SSs from more distantly related species, including pathogens of animals and humans. These findings indicate that T6SSs with shared evolutionary histories can be integrated into the cellular systems of host-associated bacteria with different effects on host health. Furthermore, we found that one T6SS in V. fischeri is located within a genomic island with high genomic plasticity. Five distinct genomic island genotypes were identified, suggesting this region encodes diverse functional potential that natural selection can act on. Finally, analysis of newly described T6SSs in roseobacter clade ANG isolates revealed a novel predicted protein that appears to be a fusion of the TssB-TssC sheath components. This work underscores the importance of studying T6SSs in diverse organisms and natural habitats to better understand how T6SSs promote the propagation of bacterial populations and impact host health.
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Affiliation(s)
- Andrea M. Suria
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Stephanie Smith
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Lauren Speare
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States,Department of Microbiology, Oregon State University, Corvallis, OR, United States
| | - Yuzhou Chen
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Iris Chien
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Emily Grace Clark
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Madelyn Krueger
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Alexander M. Warwick
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Hannah Wilkins
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States
| | - Alecia N. Septer
- Department of Earth, Marine and Environmental Sciences, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States,*Correspondence: Alecia N. Septer,
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11
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Jung H, Kim HS, Han G, Park J, Seo YS. Comparative Analyses of Four Complete Genomes in Pseudomonas amygdali Revealed Differential Adaptation to Hostile Environments and Secretion Systems. THE PLANT PATHOLOGY JOURNAL 2022; 38:167-174. [PMID: 35385921 PMCID: PMC9343901 DOI: 10.5423/ppj.nt.11.2021.0175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 03/03/2022] [Accepted: 03/10/2022] [Indexed: 06/14/2023]
Abstract
Pseudomonas amygdali is a hemibiotrophic phytopathogen that causes disease in woody and herbaceous plants. Complete genomes of four P. amygdali pathovars were comparatively analyzed to decipher the impact of genomic diversity on host colonization. The pan-genome indicated that 3,928 core genes are conserved among pathovars, while 504-1,009 are unique to specific pathovars. The unique genome contained many mobile elements and exhibited a functional distribution different from the core genome. Genes involved in O-antigen biosynthesis and antimicrobial peptide resistance were significantly enriched for adaptation to hostile environments. While the type III secretion system was distributed in the core genome, unique genomes revealed a different organization of secretion systems as follows: type I in pv. tabaci, type II in pv. japonicus, type IV in pv. morsprunorum, and type VI in pv. lachrymans. These findings provide genetic insight into the dynamic interactions of the bacteria with plant hosts.
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Affiliation(s)
- Hyejung Jung
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea
| | - Hong-Seop Kim
- Korea Seed & Variety Service, Pyeongchang 25343, Korea
| | - Gil Han
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea
| | - Jungwook Park
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea
- Environmental Microbiology Research Team, Nakdonggang National Institute of Biological Resources (NNIBR), Sangju 37242, Korea
| | - Young-Su Seo
- Department of Integrated Biological Science, Pusan National University, Busan 46241, Korea
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12
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Liyanapathiranage P, Jones JB, Potnis N. Mutation of a Single Core Gene, tssM, of Type VI Secretion System of Xanthomonas perforans Influences Virulence, Epiphytic Survival, and Transmission During Pathogenesis on Tomato. PHYTOPATHOLOGY 2022; 112:752-764. [PMID: 34543058 DOI: 10.1094/phyto-02-21-0069-r] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Xanthomonas perforans is a seedborne hemibiotrophic pathogen that successfully establishes infection in the phyllosphere of tomato. While most studies investigating mechanistic basis of pathogenesis have focused on successful apoplastic growth, factors important during asymptomatic colonization in the early stages of disease development are not well understood. In this study, we show that tssM gene of the type VI secretion system cluster i3* (T6SS-i3*) plays a significant role during initial asymptomatic epiphytic colonization at different stages during the life cycle of the pathogen. Mutation in a core gene, tssM of T6SS-i3*, imparted higher aggressiveness to the pathogen, as indicated by higher overall disease severity, higher in planta growth, and shorter latent infection period compared with the wild-type upon dip inoculation of 4- to 5-week-old tomato plants. Contribution of tssM toward aggressiveness was evident during vertical transmission from seed to seedling, with wild-type showing reduced disease severity as well as lower in planta populations on seedlings compared with the mutant. Presence of functional TssM offered higher epiphytic fitness as well as higher dissemination potential to the pathogen when tested in an experimental setup mimicking transplant house high-humidity conditions. We showed higher osmotolerance being one mechanism by which TssM offers higher epiphytic fitness. Taken together, these data reveal that functional TssM plays a larger role in offering ecological advantage to the pathogen. TssM prolongs the association of hemibiotrophic pathogen with the host, minimizing overall disease severity yet facilitating successful dissemination.
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Affiliation(s)
| | - Jeffrey B Jones
- Department of Plant Pathology, University of Florida, Gainesville, FL 32611
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, AL 36849
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13
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Chou L, Lin YC, Haryono M, Santos MNM, Cho ST, Weisberg AJ, Wu CF, Chang JH, Lai EM, Kuo CH. Modular evolution of secretion systems and virulence plasmids in a bacterial species complex. BMC Biol 2022; 20:16. [PMID: 35022048 PMCID: PMC8756689 DOI: 10.1186/s12915-021-01221-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 12/23/2021] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Many named species as defined in current bacterial taxonomy correspond to species complexes. Uncertainties regarding the organization of their genetic diversity challenge research efforts. We utilized the Agrobacterium tumefaciens species complex (a.k.a. Agrobacterium biovar 1), a taxon known for its phytopathogenicity and applications in transformation, as a study system and devised strategies for investigating genome diversity and evolution of species complexes. RESULTS We utilized 35 genome assemblies, including 14 newly generated ones, to achieve a phylogenetically balanced sampling of A. tumefaciens. Our genomic analysis suggested that the 10 genomospecies described previously are distinct biological species and supported a quantitative guideline for species delineation. Furthermore, our inference of gene content and core-genome phylogeny allowed for investigations of genes critical in fitness and ecology. For the type VI secretion system (T6SS) involved in interbacterial competition and thought to be conserved, we detected multiple losses and one horizontal gene transfer. For the tumor-inducing plasmids (pTi) and pTi-encoded type IV secretion system (T4SS) that are essential for agrobacterial phytopathogenicity, we uncovered novel diversity and hypothesized their involvement in shaping this species complex. Intriguingly, for both T6SS and T4SS, genes encoding structural components are highly conserved, whereas extensive diversity exists for genes encoding effectors and other proteins. CONCLUSIONS We demonstrate that the combination of a phylogeny-guided sampling scheme and an emphasis on high-quality assemblies provides a cost-effective approach for robust analysis in evolutionary genomics. We show that the T6SS VgrG proteins involved in specific effector binding and delivery can be classified into distinct types based on domain organization. The co-occurrence patterns of VgrG-associated domains and the neighboring genes that encode different chaperones/effectors can be used to infer possible interacting partners. Similarly, the associations between plant host preference and the pTi type among these strains can be used to infer phenotype-genotype correspondence. Our strategies for multi-level investigations at scales that range from whole genomes to intragenic domains and phylogenetic depths from between- to within-species are applicable to other bacteria. Furthermore, modularity observed in the molecular evolution of genes and domains is useful for inferring functional constraints and informing experimental works.
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Affiliation(s)
- Lin Chou
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Yu-Chen Lin
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Mindia Haryono
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Mary Nia M Santos
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan.,Graduate Institute of Biotechnology, National Chung Hsing University, Taichung, Taiwan
| | - Shu-Ting Cho
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Alexandra J Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Chih-Feng Wu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan.,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan.,Biotechnology Center, National Chung Hsing University, Taichung, Taiwan
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan. .,Molecular and Biological Agricultural Sciences Program, Taiwan International Graduate Program, National Chung Hsing University and Academia Sinica, Taipei, Taiwan. .,Biotechnology Center, National Chung Hsing University, Taichung, Taiwan.
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14
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Czolkoss S, Safronov X, Rexroth S, Knoke LR, Aktas M, Narberhaus F. Agrobacterium tumefaciens Type IV and Type VI Secretion Systems Reside in Detergent-Resistant Membranes. Front Microbiol 2021; 12:754486. [PMID: 34899640 PMCID: PMC8656257 DOI: 10.3389/fmicb.2021.754486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/25/2021] [Indexed: 11/17/2022] Open
Abstract
Cell membranes are not homogenous but compartmentalized into lateral microdomains, which are considered as biochemical reaction centers for various physiological processes in eukaryotes and prokaryotes. Due to their special lipid and protein composition, some of these microdomains are resistant to treatment with non-ionic detergents and can be purified as detergent-resistant membranes (DRMs). Here we report the proteome of DRMs from the Gram-negative phytopathogen Agrobacterium tumefaciens. Using label-free liquid chromatography-tandem mass spectrometry, we identified proteins enriched in DRMs isolated under normal and virulence-mimicking growth conditions. Prominent microdomain marker proteins such as the SPFH (stomatin/prohibitin/flotillin/HflKC) proteins HflK, HflC and Atu3772, along with the protease FtsH were highly enriched in DRMs isolated under any given condition. Moreover, proteins involved in cell envelope biogenesis, transport and secretion, as well as motility- and chemotaxis-associated proteins were overrepresented in DRMs. Most strikingly, we found virulence-associated proteins such as the VirA/VirG two-component system, and the membrane-spanning type IV and type VI secretion systems enriched in DRMs. Fluorescence microscopy of the cellular localization of both secretion systems and of marker proteins was in agreement with the results from the proteomics approach. These findings suggest that virulence traits are micro-compartmentalized into functional microdomains in A. tumefaciens.
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Affiliation(s)
- Simon Czolkoss
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Xenia Safronov
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Sascha Rexroth
- Department of Plant Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Lisa R Knoke
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Meriyem Aktas
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
| | - Franz Narberhaus
- Department of Microbial Biology, Ruhr University Bochum, Bochum, Germany
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15
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Gallegos-Monterrosa R, Coulthurst SJ. The ecological impact of a bacterial weapon: microbial interactions and the Type VI secretion system. FEMS Microbiol Rev 2021; 45:fuab033. [PMID: 34156081 PMCID: PMC8632748 DOI: 10.1093/femsre/fuab033] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 06/20/2021] [Indexed: 12/13/2022] Open
Abstract
Bacteria inhabit all known ecological niches and establish interactions with organisms from all kingdoms of life. These interactions are mediated by a wide variety of mechanisms and very often involve the secretion of diverse molecules from the bacterial cells. The Type VI secretion system (T6SS) is a bacterial protein secretion system that uses a bacteriophage-like machinery to secrete a diverse array of effectors, usually translocating them directly into neighbouring cells. These effectors display toxic activity in the recipient cell, making the T6SS an effective weapon during inter-bacterial competition and interactions with eukaryotic cells. Over the last two decades, microbiology research has experienced a shift towards using systems-based approaches to study the interactions between diverse organisms and their communities in an ecological context. Here, we focus on this aspect of the T6SS. We consider how our perspective of the T6SS has developed and examine what is currently known about the impact that bacteria deploying the T6SS can have in diverse environments, including niches associated with plants, insects and mammals. We consider how T6SS-mediated interactions can affect host organisms by shaping their microbiota, as well as the diverse interactions that can be established between different microorganisms through the deployment of this versatile secretion system.
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Affiliation(s)
| | - Sarah J Coulthurst
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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16
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Wu CF, Weisberg AJ, Davis EW, Chou L, Khan S, Lai EM, Kuo CH, Chang JH. Diversification of the Type VI Secretion System in Agrobacteria. mBio 2021; 12:e0192721. [PMID: 34517758 PMCID: PMC8546570 DOI: 10.1128/mbio.01927-21] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 08/16/2021] [Indexed: 12/13/2022] Open
Abstract
The type VI secretion system (T6SS) is used by many Gram-negative bacteria to deploy toxic effectors for interbacterial competition. This system provides a competitive advantage in planta to agrobacteria, a diverse group with phytopathogenic members capable of genetically transforming plants. To inform on the ecology and evolution of agrobacteria, we revealed processes that diversify their effector gene collections. From genome sequences of diverse strains, we identified T6SS loci, functionally validated associated effector genes for toxicity, and predicted genes homologous to those that encode proteins known to interact with effectors. The gene loci were analyzed in a phylogenetic framework, and results show that strains of some species-level groups have different patterns of T6SS expression and are enriched in specific sets of T6SS loci. Findings also demonstrate that the modularity of T6SS loci and their associated genes engenders dynamicity, promoting reshuffling of entire loci, fragments therein, and domains to swap toxic effector genes across species. However, diversification is constrained by the need to maintain specific combinations of gene subtypes, congruent with observations that certain genes function together to regulate T6SS loading and activation. Data are consistent with a scenario where species can acquire unique T6SS loci that are then reshuffled across the genus in a restricted manner to generate new combinations of effector genes. IMPORTANCE The T6SS is used by several taxa of Gram-negative bacteria to secrete toxic effector proteins to attack others. Diversification of effector collections shapes bacterial interactions and impacts the health of hosts and ecosystems in which bacteria reside. We uncovered the diversity of T6SS loci across a genus of plant-associated bacteria and show that diversification is driven by the acquisition of new loci and reshuffling among species. However, linkages between specific subtypes of genes need to be maintained to ensure that proteins whose interactions are necessary to activate the T6SS remain together. Results reveal how organization of gene loci and domain structure of genes provides flexibility to diversify under the constraints imposed by the system. Findings inform on the evolution of a mechanism that influences bacterial communities.
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Affiliation(s)
- Chih-Feng Wu
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Alexandra J. Weisberg
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Edward W. Davis
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
- Molecular and Cellular Biology Program, Oregon State University, Corvallis, Oregon, USA
| | - Lin Chou
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Surtaz Khan
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Chih-Horng Kuo
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan
| | - Jeff H. Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, Oregon, USA
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17
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Activation of the type VI secretion system in the squid symbiont Vibrio fischeri requires the transcriptional regulator TasR and the structural proteins TssM and TssA. J Bacteriol 2021; 203:e0039921. [PMID: 34370559 PMCID: PMC8508121 DOI: 10.1128/jb.00399-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Bacteria have evolved diverse strategies to compete for a niche, including the type VI secretion system (T6SS), a contact-dependent killing mechanism. T6SSs are common in bacterial pathogens, commensals, and beneficial symbionts, where they affect the diversity and spatial structure of host-associated microbial communities. Although T6SS gene clusters are often located on genomic islands (GIs), which may be transferred as a unit, the regulatory strategies that promote gene expression once the T6SS genes are transferred into a new cell are not known. We used the squid symbiont, Vibrio fischeri, to identify essential regulatory factors that control expression of a strain-specific T6SS encoded on a GI. We found that a transcriptional reporter for this T6SS is active only in strains that contain the T6SS-encoding GI, suggesting the GI encodes at least one essential regulator. A transposon screen identified seven mutants that could not activate the reporter. These mutations mapped exclusively to three genes on the T6SS-containing GI that encode two essential structural proteins (a TssA-like protein and TssM) and a transcriptional regulator (TasR). Using T6SS reporters, RT-PCR, competition assays, and differential proteomics, we found that all three genes are required for expression of many T6SS components, except for the TssA-like protein and TssM, which are constitutively expressed. Based on these findings, we propose a model whereby T6SS expression requires conserved structural proteins, in addition to the essential regulator TasR, and this ability to self-regulate may be a strategy to activate T6SS expression upon transfer of T6SS-encoding elements into a new bacterial host. Importance Interbacterial weapons like the T6SS are often located on mobile genetic elements and their expression is highly regulated. We found that two conserved structural proteins are required for T6SS expression in Vibrio fischeri. These structural proteins also contain predicted GTPase and GTP binding domains, suggesting their role in promoting T6SS expression may involve sensing the energetic state of the cell. Such a mechanism would provide a direct link between T6SS activation and cellular energy levels, providing a "checkpoint" to ensure the cell has sufficient energy to build such a costly weapon. Because these regulatory factors are encoded within the T6SS gene cluster, they are predicted to move with the genetic element to activate T6SS expression in a new host cell.
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18
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Durán D, Bernal P, Vazquez-Arias D, Blanco-Romero E, Garrido-Sanz D, Redondo-Nieto M, Rivilla R, Martín M. Pseudomonas fluorescens F113 type VI secretion systems mediate bacterial killing and adaption to the rhizosphere microbiome. Sci Rep 2021; 11:5772. [PMID: 33707614 PMCID: PMC7970981 DOI: 10.1038/s41598-021-85218-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 02/26/2021] [Indexed: 02/06/2023] Open
Abstract
The genome of Pseudomonas fluorescens F113, a model rhizobacterium and a plant growth-promoting agent, encodes three putative type VI secretion systems (T6SSs); F1-, F2- and F3-T6SS. Bioinformatic analysis of the F113 T6SSs has revealed that they belong to group 3, group 1.1, and group 4a, respectively, similar to those previously described in Pseudomonas aeruginosa. In addition, in silico analyses allowed us to identify genes encoding a total of five orphan VgrG proteins and eight putative effectors (Tfe), some with their cognate immunity protein (Tfi) pairs. Genes encoding Tfe and Tfi are found in the proximity of P. fluorescens F113 vgrG, hcp, eagR and tap genes. RNA-Seq analyses in liquid culture and rhizosphere have revealed that F1- and F3-T6SS are expressed under all conditions, indicating that they are active systems, while F2-T6SS did not show any relevant expression under the tested conditions. The analysis of structural mutants in the three T6SSs has shown that the active F1- and F3-T6SSs are involved in interbacterial killing while F2 is not active in these conditions and its role is still unknown.. A rhizosphere colonization analysis of the double mutant affected in the F1- and F3-T6SS clusters showed that the double mutant was severely impaired in persistence in the rhizosphere microbiome, revealing the importance of these two systems for rhizosphere adaption.
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Affiliation(s)
- David Durán
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Patricia Bernal
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain.,Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Avenida de la Reina Mercedes, 6, 41012, Sevilla, Spain
| | - David Vazquez-Arias
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Esther Blanco-Romero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Daniel Garrido-Sanz
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Miguel Redondo-Nieto
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Rafael Rivilla
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin, 2, 28049, Madrid, Spain.
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19
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Montenegro Benavides NA, Alvarez B A, Arrieta-Ortiz ML, Rodriguez-R LM, Botero D, Tabima JF, Castiblanco L, Trujillo C, Restrepo S, Bernal A. The type VI secretion system of Xanthomonas phaseoli pv. manihotis is involved in virulence and in vitro motility. BMC Microbiol 2021; 21:14. [PMID: 33407123 PMCID: PMC7788950 DOI: 10.1186/s12866-020-02066-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Accepted: 12/08/2020] [Indexed: 12/12/2022] Open
Abstract
Background The type VI protein secretion system (T6SS) is important in diverse cellular processes in Gram-negative bacteria, including interactions with other bacteria and with eukaryotic hosts. In this study we analyze the evolution of the T6SS in the genus Xanthomonas and evaluate its importance of the T6SS for virulence and in vitro motility in Xanthomonas phaseoli pv. manihotis (Xpm), the causal agent of bacterial blight in cassava (Manihot esculenta). We delineate the organization of the T6SS gene clusters in Xanthomonas and then characterize proteins of this secretion system in Xpm strain CIO151. Results We describe the presence of three different clusters in the genus Xanthomonas that vary in their organization and degree of synteny between species. Using a gene knockout strategy, we also found that vgrG and hcp are required for maximal aggressiveness of Xpm on cassava plants while clpV is important for both motility and maximal aggressiveness. Conclusion We characterized the T6SS in 15 different strains in Xanthomonas and our phylogenetic analyses suggest that the T6SS might have been acquired by a very ancient event of horizontal gene transfer and maintained through evolution, hinting at their importance for the adaptation of Xanthomonas to their hosts. Finally, we demonstrated that the T6SS of Xpm is functional, and significantly contributes to virulence and motility. This is the first experimental study that demonstrates the role of the T6SS in the Xpm-cassava interaction and the T6SS organization in the genus Xanthomonas. Supplementary Information The online version contains supplementary material available at 10.1186/s12866-020-02066-1.
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Affiliation(s)
| | - Alejandro Alvarez B
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | | | - Luis Miguel Rodriguez-R
- Department of Microbiology and Digital Science Center (DiSC), University of Innsbruck, Innsbruck, Tyrol, Austria
| | - David Botero
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Javier Felipe Tabima
- Botany and Plant Pathology Department, Oregon State University, Corvallis, OR, USA
| | - Luisa Castiblanco
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Cesar Trujillo
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Silvia Restrepo
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia
| | - Adriana Bernal
- Department of Biological Sciences, Universidad de los Andes, Bogotá, Colombia.
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20
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Salinero-Lanzarote A, Pacheco-Moreno A, Domingo-Serrano L, Durán D, Ormeño-Orrillo E, Martínez-Romero E, Albareda M, Palacios JM, Rey L. The Type VI secretion system of Rhizobium etli Mim1 has a positive effect in symbiosis. FEMS Microbiol Ecol 2020; 95:5449006. [PMID: 30977796 DOI: 10.1093/femsec/fiz054] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 04/11/2019] [Indexed: 12/18/2022] Open
Abstract
The Type VI secretion systems (T6SSs) allow bacteria to translocate effector proteins to other bacteria or to eukaryotic cells. However, little is known about the role of T6SS in endosymbiotic bacteria. In this work we describe the T6SS of Rhizobium etli Mim1, a bacteria able to effectively nodulate common beans. Structural genes and those encoding possible effectors have been identified in a 28-gene DNA region of R. etli Mim1 pRetMIM1f plasmid. Immunodetection of Hcp protein, a conserved key structural component of T6SS systems, indicates that this secretion system is active at high cell densities, in the presence of root exudates, and in bean nodules. Rhizobium etli mutants affected in T6SS structural genes produced plants with lower dry weight and smaller nodules than the wild-type strain, indicating for the first time that the T6SS plays a positive role in Rhizobium-legume symbiosis.
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Affiliation(s)
- Alvaro Salinero-Lanzarote
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, 28223 Madrid, Spain.,Departamento de Biotecnología y Biología Vegetal, ETSI Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | - Alba Pacheco-Moreno
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, 28223 Madrid, Spain.,Departamento de Biotecnología y Biología Vegetal, ETSI Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | - Lucía Domingo-Serrano
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, 28223 Madrid, Spain.,Departamento de Biotecnología y Biología Vegetal, ETSI Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | - David Durán
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, 28223 Madrid, Spain.,Departamento de Biotecnología y Biología Vegetal, ETSI Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | | | | | - Marta Albareda
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, 28223 Madrid, Spain.,Departamento de Biotecnología y Biología Vegetal, ETSI Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | - José Manuel Palacios
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, 28223 Madrid, Spain.,Departamento de Biotecnología y Biología Vegetal, ETSI Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28040 Madrid, Spain
| | - Luis Rey
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM)-Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus de Montegancedo, 28223 Madrid, Spain.,Departamento de Biotecnología y Biología Vegetal, ETSI Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, 28040 Madrid, Spain
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21
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Zhang Z, Li D, Shi X, Zhai Y, Guo Y, Zheng Y, Zhao L, He Y, Chen Y, Wang Z, Su J, Kang Y, Gao Z. Genomic characterization of an emerging Enterobacteriaceae species: the first case of co-infection with a typical pathogen in a human patient. BMC Genomics 2020; 21:297. [PMID: 32293254 PMCID: PMC7156906 DOI: 10.1186/s12864-020-6720-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 04/05/2020] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Opportunistic pathogens are important for clinical practice as they often cause antibiotic-resistant infections. However, little is documented for many emerging opportunistic pathogens and their biological characteristics. Here, we isolated a strain of extended-spectrum β-lactamase-producing Enterobacteriaceae from a patient with a biliary tract infection. We explored the biological and genomic characteristics of this strain to provide new evidence and detailed information for opportunistic pathogens about the co-infection they may cause. RESULTS The isolate grew very slowly but conferred strong protection for the co-infected cephalosporin-sensitive Klebsiella pneumoniae. As the initial laboratory testing failed to identify the taxonomy of the strain, great perplexity was caused in the etiological diagnosis and anti-infection treatment for the patient. Rigorous sequencing efforts achieved the complete genome sequence of the isolate which we designated as AF18. AF18 is phylogenetically close to a few strains isolated from soil, clinical sewage, and patients, forming a novel species together, while the taxonomic nomenclature of which is still under discussion. And this is the first report of human infection of this novel species. Like its relatives, AF18 harbors many genes related to cell mobility, various genes adaptive to both the natural environment and animal host, over 30 mobile genetic elements, and a plasmid bearing blaCTX-M-3 gene, indicating its ability to disseminate antimicrobial-resistant genes from the natural environment to patients. Transcriptome sequencing identified two sRNAs that critically regulate the growth rate of AF18, which could serve as targets for novel antimicrobial strategies. CONCLUSIONS Our findings imply that AF18 and its species are not only infection-relevant but also potential disseminators of antibiotic resistance genes, which highlights the need for continuous monitoring for this novel species and efforts to develop treatment strategies.
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Affiliation(s)
- Zhao Zhang
- Department of Respiratory & Critical Care Medicine, Peking University People's Hospital, Beijing, Beijing, China.,Department of Respiratory & Critical Care Medicine, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Daixi Li
- Department of Respiratory & Critical Care Medicine, Peking University People's Hospital, Beijing, Beijing, China.,Department of Respiratory and Critical Care Medicine, Zhongshan Hospital Xiamen University, Xiamen, 361004, Fujian, China
| | - Xing Shi
- Department of Respiratory & Critical Care Medicine, Peking University People's Hospital, Beijing, Beijing, China.,Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, Beijing, China
| | - Yao Zhai
- University of Technology Sydney, Ultimo, NSW, Australia
| | - Yatao Guo
- Department of Respiratory & Critical Care Medicine, Peking University People's Hospital, Beijing, Beijing, China.,Department of Respiratory & Critical Care Medicine, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Yali Zheng
- Department of Respiratory & Critical Care Medicine, Peking University People's Hospital, Beijing, Beijing, China.,Department of Respiratory, Critical Care and Sleep Medicine, Xiamen University Xiang'an Hospital, Xiamen, Fujian, China
| | - Lili Zhao
- Department of Respiratory & Critical Care Medicine, Peking University People's Hospital, Beijing, Beijing, China
| | - Yukun He
- Department of Respiratory & Critical Care Medicine, Peking University People's Hospital, Beijing, Beijing, China
| | - Yusheng Chen
- Department of Respiratory & Critical Care Medicine, Fujian Provincial Hospital, Fuzhou, Fujian, China
| | - Zhanwei Wang
- Laboratory Medicine, Peking University People's Hospital, Beijing, China
| | - Jianrong Su
- Department of Clinical Laboratory Center, Beijing Friendship Hospital, Beijing, Beijing, China
| | - Yu Kang
- Beijing Institute of Genomics, Chinese Academy of Sciences, Beijing, Beijing, China.
| | - Zhancheng Gao
- Department of Respiratory & Critical Care Medicine, Peking University People's Hospital, Beijing, Beijing, China.
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22
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Horizontally Acquired Quorum-Sensing Regulators Recruited by the PhoP Regulatory Network Expand the Host Adaptation Repertoire in the Phytopathogen Pectobacterium brasiliense. mSystems 2020; 5:5/1/e00650-19. [PMID: 31992632 PMCID: PMC6989131 DOI: 10.1128/msystems.00650-19] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In this study, we examine the impact of transcriptional network rearrangements driven by horizontal gene acquisition in PhoP and SlyA regulons using as a case study a phytopathosystem comprised of potato tubers and the soft-rot pathogen Pectobacterium brasiliense 1692 (Pb1692). Genome simulations and statistical analyses uncovered the tendency of PhoP and SlyA networks to mobilize lineage-specific traits predicted as horizontal gene transfer at late infection, highlighting the prominence of regulatory network rearrangements in this stage of infection. The evidence further supports the circumscription of two horizontally acquired quorum-sensing regulators (carR and expR1) by the PhoP network. By recruiting carR and expR1, the PhoP network also impacts certain host adaptation- and bacterial competition-related systems, seemingly in a quorum sensing-dependent manner, such as the type VI secretion system, carbapenem biosynthesis, and plant cell wall-degrading enzymes (PCWDE) like cellulases and pectate lyases. Conversely, polygalacturonases and the type III secretion system (T3SS) exhibit a transcriptional pattern that suggests quorum-sensing-independent regulation by the PhoP network. This includes an uncharacterized novel phage-related gene family within the T3SS gene cluster that has been recently acquired by two Pectobacterium species. The evidence further suggests a PhoP-dependent regulation of carbapenem- and PCWDE-encoding genes based on the synthesized products' optimum pH. The PhoP network also controls slyA expression in planta, which seems to impact carbohydrate metabolism regulation, especially at early infection, when 76.2% of the SlyA-regulated genes from that category also require PhoP to achieve normal expression levels.IMPORTANCE Exchanging genetic material through horizontal transfer is a critical mechanism that drives bacteria to efficiently adapt to host defenses. In this report, we demonstrate that a specific plant-pathogenic species (from the Pectobacterium genus) successfully integrated a population density-based behavior system (quorum sensing) acquired through horizontal transfer into a resident stress-response gene regulatory network controlled by the PhoP protein. Evidence found here underscores that subsets of bacterial weaponry critical for colonization, typically known to respond to quorum sensing, are also controlled by PhoP. Some of these traits include different types of enzymes that can efficiently break down plant cell walls depending on the environmental acidity level. Thus, we hypothesize that PhoP's ability to elicit regulatory responses based on acidity and nutrient availability fluctuations has strongly impacted the fixation of its regulatory connection with quorum sensing. In addition, another global gene regulator, known as SlyA, was found under the PhoP regulatory network. The SlyA regulator controls a series of carbohydrate metabolism-related traits, which also seem to be regulated by PhoP. By centralizing quorum sensing and slyA under PhoP scrutiny, Pectobacterium cells added an advantageous layer of control over those two networks that potentially enhances colonization efficiency.
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23
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Wu C, Lien Y, Bondage D, Lin J, Pilhofer M, Shih Y, Chang JH, Lai E. Effector loading onto the VgrG carrier activates type VI secretion system assembly. EMBO Rep 2020; 21:e47961. [PMID: 31808291 PMCID: PMC6945064 DOI: 10.15252/embr.201947961] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 11/12/2019] [Accepted: 11/15/2019] [Indexed: 01/08/2023] Open
Abstract
The type VI secretion system (T6SS) is used by many bacteria to engage in social behavior and can affect the health of its host plant or animal. Because activities associated with T6SSs are often costly, T6SSs must be tightly regulated. However, our knowledge regarding how T6SS assembly and contraction are regulated remains limited. Using the plant pathogen Agrobacterium tumefaciens, we show that effectors are not just passengers but also impact on T6SS assembly. The A. tumefaciens strain C58 encodes one T6SS and two Tde DNase toxin effectors used as major weapons for interbacterial competition. Here, we demonstrate that loading of Tde effectors onto their cognate carriers, the VgrG spikes, is required for active T6SS secretion. The assembly of the TssBC contractile sheath occurs only in the presence of Tde effectors. The requirement of effector loading for efficient T6SS secretion was also validated in other A. tumefaciens strains. We propose that such a mechanism is used by bacteria as a strategy for efficacious T6SS firing and to ensure that effectors are loaded onto the T6SS prior to completing its assembly.
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Affiliation(s)
- Chih‐Feng Wu
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan
- Department of Botany and Plant PathologyOregon State UniversityCorvallisORUSA
| | - Yun‐Wei Lien
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan
- Department of Plant Pathology and MicrobiologyNational Taiwan UniversityTaipeiTaiwan
- Institute of Molecular Biology & BiophysicsEidgenössische Technische Hochschule ZürichZürichSwitzerland
| | - Devanand Bondage
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan
- Present address:
Division of Molecular and Cellular BiologyEunice Kennedy Shriver National Institute of Child Health and Human DevelopmentNational Institutes of HealthBethesdaMDUSA
| | - Jer‐Sheng Lin
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan
- Present address:
Department of Organismic InteractionsMax Planck Institute for Terrestrial MicrobiologyMarburgGermany
| | - Martin Pilhofer
- Institute of Molecular Biology & BiophysicsEidgenössische Technische Hochschule ZürichZürichSwitzerland
| | - Yu‐Ling Shih
- Institute of Biological ChemistryAcademia SinicaTaipeiTaiwan
| | - Jeff H Chang
- Department of Botany and Plant PathologyOregon State UniversityCorvallisORUSA
- Center for Genome Research and BiocomputingOregon State UniversityCorvallisORUSA
| | - Erh‐Min Lai
- Institute of Plant and Microbial BiologyAcademia SinicaTaipeiTaiwan
- Department of Plant Pathology and MicrobiologyNational Taiwan UniversityTaipeiTaiwan
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24
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Hu YY, Liu CX, Liu P, Wu ZY, Zhang YD, Xiong XS, Li XY. Regulation of gene expression of hcp, a core gene of the type VI secretion system in Acinetobacter baumannii causing respiratory tract infection. J Med Microbiol 2019; 67:945-951. [PMID: 29771233 DOI: 10.1099/jmm.0.000753] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Purpose. The objective of the current study was to investigate whether hcp plays a role in the process of Acinetobacter baumannii infection and to examine clinically relevant factors that may affect hcp expression.Methodology. Seventy-seven A. baumannii isolates from patients with a respiratory infection at the Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University (Wenzhou, China) were included in this study. PCR was performed to screen for the presence of hcp. Quantitative real time polymerase chain reaction (qRT-PCR) was carried out to examine the expression of hcp.Results. A total of 77.9 % (60 of 77) of the A. baumannii clinical isolates possessed the hcp gene. Expression of hcp was found to be strain-specific and associated with the infection status. Higher gene expression of hcp was found for invasive A. baumannii isolates causing an infection relative to the colonization group, and for the same strain at a post-infection status compared with that prior to infection. Acid environment was also found to be a trigger of hcp gene expression.Conclusion. The type VI secretion system and hcp predominate in A. baumannii causing respiratory infections. Expression of hcp is regulated by the infection status and acid environment, and might play a role in the process of triggering infection by the colonizer.
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Affiliation(s)
- Yin-Yin Hu
- Department of Clinical Laboratory, Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University, Wenzhou, PR China
| | - Cai-Xia Liu
- Department of Clinical Laboratory, Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University, Wenzhou, PR China
| | - Peng Liu
- Department of Clinical Laboratory, Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University, Wenzhou, PR China
| | - Zhuo-Ying Wu
- Department of Clinical Laboratory, Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University, Wenzhou, PR China
| | - Ya-Dong Zhang
- Department of Hepatobiliary Surgery, Affiliated Qingdao Municipal Hospital of Qingdao University, Qingdao, PR China
| | - Xiao-Shun Xiong
- Department of Clinical Laboratory, Second Affiliated Hospital of Nanchang University, Nanchang, PR China
| | - Xiang-Yang Li
- Department of Clinical Laboratory, Second Affiliated Hospital and Yuying Childrens Hospital of Wenzhou Medical University, Wenzhou, PR China
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25
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Navarro-Garcia F, Ruiz-Perez F, Cataldi Á, Larzábal M. Type VI Secretion System in Pathogenic Escherichia coli: Structure, Role in Virulence, and Acquisition. Front Microbiol 2019; 10:1965. [PMID: 31543869 PMCID: PMC6730261 DOI: 10.3389/fmicb.2019.01965] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 08/09/2019] [Indexed: 12/18/2022] Open
Abstract
Bacterial pathogens utilize a myriad of mechanisms to invade mammalian hosts, damage tissue sites, and evade the immune system. One essential strategy of Gram-negative bacteria is the secretion of virulence factors through both inner and outer membranes to reach a potential target. Most secretion systems are harbored in mobile elements including transposons, plasmids, pathogenicity islands, and phages, and Escherichia coli is one of the more versatile bacteria adopting this genetic information by horizontal gene transfer. Additionally, E. coli is a bacterial species with members of the commensal intestinal microbiota and pathogens associated with numerous types of infections such as intestinal, urinary, and systemic in humans and other animals. T6SS cluster plasticity suggests evolutionarily divergent systems were acquired horizontally. T6SS is a secretion nanomachine that is extended through the bacterial double membrane; from this apparatus, substrates are conveyed straight from the cytoplasm of the bacterium into a target cell or to the extracellular space. This nanomachine consists of three main complexes: proteins in the inner membrane that are T4SS component-like, the baseplate complex, and the tail complex, which are formed by components evolutionarily related to contractile bacteriophage tails. Advances in the T6SS understanding include the functional and structural characterization of at least 13 subunits (so-called core components), which are thought to comprise the minimal apparatus. So far, the main role of T6SS is on bacterial competition by using it to kill neighboring non-immune bacteria for which antibacterial proteins are secreted directly into the periplasm of the bacterial target after cell-cell contact. Interestingly, a few T6SSs have been associated directly to pathogenesis, e.g., roles in biofilm formation and macrophage survival. Here, we focus on the advances on T6SS from the perspective of E. coli pathotypes with emphasis in the secretion apparatus architecture, the mechanisms of pathogenicity of effector proteins, and the events of lateral gene transfer that led to its spread.
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Affiliation(s)
- Fernando Navarro-Garcia
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del IPN (CINVESTAV-IPN), Mexico City, Mexico
| | - Fernando Ruiz-Perez
- Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, VA, United States
| | - Ángel Cataldi
- Laboratorio de Escherichia coli, Instituto de Agrobiotecnología y Biología Molecular (IABIMO) INTA-CONICET, Buenos Aires, Argentina
| | - Mariano Larzábal
- Laboratorio de Escherichia coli, Instituto de Agrobiotecnología y Biología Molecular (IABIMO) INTA-CONICET, Buenos Aires, Argentina
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26
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Soni N, Swain SK, Kant R, Singh A, Ravichandran R, Verma SK, Panda PK, Suar M. Landscape of ROD9 Island: Functional annotations and biological network of hypothetical proteins in Salmonella enterica. Comput Biol Chem 2019; 83:107110. [PMID: 31445418 DOI: 10.1016/j.compbiolchem.2019.107110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 07/16/2019] [Accepted: 08/13/2019] [Indexed: 01/01/2023]
Abstract
Salmonella, an Enterobacteria is a therapeutically important pathogen for the host. The advancement of genome sequencing of S. enterica serovar Enteritidis have identified a distinct ROD9 pathogenic island, imparting virulence. The occurrence of 17 ROD9 hypothetical proteins, necessitates subsequent bioinformatics approach for structural and functional aspects of protein-protein relations or networks in different pathogenic phenotypes express. A collective analysis using predictive bioinformatics tools that includes NCBI-BLASTp and BLAST2GO annotated the motif patterns and functional significance. The VFDB identified 10 virulence proteins at both genomic and metagenomic level. Phylogenetic analysis revealed a divergent and convergent relationship between 17 ROD9 and 41 SP-1 proteins. Here, combining a comprehensive approach from sequence based, motif recognitions, domain identification, virulence ability to structural modelling provides a precise function to ROD9 proteins biological network, for which no experimental information is available.
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Affiliation(s)
- Nikita Soni
- School of Biotechnology and Bioinformatics, D. Y. Patil (Deemed to be University), Navi Mumbai, India
| | | | - Ravi Kant
- University of Delhi, New Delhi, India
| | - Aditya Singh
- School of Biotechnology and Bioinformatics, D. Y. Patil (Deemed to be University), Navi Mumbai, India
| | - Rahul Ravichandran
- School of Chemical and Biotechnology, SASTRA University, Tamil Nadu, India
| | - Suresh K Verma
- Institute of Environmental Medicine (IMM), C6, Molecular Toxicology, Karolinska Institutet, Sweden
| | - Pritam Kumar Panda
- Division of Pediatric Hematology and Oncology, University Medical Center, University of Freiburg, Germany.
| | - Mrutyunjay Suar
- School of Biotechnology, KIIT University, Bhubaneswar, India.
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27
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Wu CF, Santos MNM, Cho ST, Chang HH, Tsai YM, Smith DA, Kuo CH, Chang JH, Lai EM. Plant-Pathogenic Agrobacterium tumefaciens Strains Have Diverse Type VI Effector-Immunity Pairs and Vary in In-Planta Competitiveness. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:961-971. [PMID: 30830835 DOI: 10.1094/mpmi-01-19-0021-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The type VI secretion system (T6SS) is used by gram-negative bacteria to translocate effectors that can antagonize other bacterial cells. Models predict the variation in collections of effector and cognate immunity genes determine competitiveness and can affect the dynamics of populations and communities of bacteria. However, the outcomes of competition cannot be entirely explained by compatibility of effector-immunity (EI) pairs. Here, we characterized the diversity of T6SS loci of plant-pathogenic Agrobacterium tumefaciens and showed that factors other than EI pairs can impact interbacterial competition. All examined strains encode T6SS active in secretion and antagonism against Escherichia coli. The spectra of EI pairs as well as compositions of gene neighborhoods are diverse. Almost 30 in-planta competitions were tested between different genotypes of A. tumefaciens. Fifteen competitions between members of different species-level groups resulted in T6SS-dependent suppression in in-planta growth of prey genotypes. In contrast, ten competitions between members within species-level groups resulted in no significant effect on the growth of prey genotypes. One strain was an exceptional case and, despite encoding a functional T6SS and toxic effector protein, could not compromise the growth of the four tested prey genotypes. The data suggest T6SS-associated EI pairs can influence the competitiveness of strains of A. tumefaciens, but genetic features have a significant role on the efficacy of interbacterial antagonism.
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Affiliation(s)
- Chih-Feng Wu
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
- 2Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, U.S.A
| | - Mary Nia M Santos
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Shu-Ting Cho
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Hsing-Hua Chang
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Yi-Ming Tsai
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Delaney A Smith
- 2Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, U.S.A
| | - Chih-Horng Kuo
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
| | - Jeff H Chang
- 2Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, U.S.A
- 3Center for Genome Research and Biocomputing, Oregon State University
| | - Erh-Min Lai
- 1Institute of Plant and Microbial Biology, Academia Sinica, Taipei 11529, Taiwan
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28
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McCarthy RR, Yu M, Eilers K, Wang Y, Lai E, Filloux A. Cyclic di-GMP inactivates T6SS and T4SS activity in Agrobacterium tumefaciens. Mol Microbiol 2019; 112:632-648. [PMID: 31102484 PMCID: PMC6771610 DOI: 10.1111/mmi.14279] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/15/2019] [Indexed: 01/17/2023]
Abstract
The Type VI secretion system (T6SS) is a bacterial nanomachine that delivers effector proteins into prokaryotic and eukaryotic preys. This secretion system has emerged as a key player in regulating the microbial diversity in a population. In the plant pathogen Agrobacterium tumefaciens, the signalling cascades regulating the activity of this secretion system are poorly understood. Here, we outline how the universal eubacterial second messenger cyclic di-GMP impacts the production of T6SS toxins and T6SS structural components. We demonstrate that this has a significant impact on the ability of the phytopathogen to compete with other bacterial species in vitro and in planta. Our results suggest that, as opposed to other bacteria, c-di-GMP turns down the T6SS in A. tumefaciens thus impacting its ability to compete with other bacterial species within the rhizosphere. We also demonstrate that elevated levels of c-di-GMP within the cell decrease the activity of the Type IV secretion system (T4SS) and subsequently the capacity of A. tumefaciens to transform plant cells. We propose that such peculiar control reflects on c-di-GMP being a key second messenger that silences energy-costing systems during early colonization phase and biofilm formation, while low c-di-GMP levels unleash T6SS and T4SS to advance plant colonization.
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Affiliation(s)
- Ronan R. McCarthy
- MRC Centre for Molecular Bacteriology and Infection, Department of Life SciencesImperial College LondonLondonSW7 2AZUK
- Division of Biosciences, Department of Life SciencesCollege of Health and Life Sciences, Brunel University LondonUxbridgeUB8 3PHUK
| | - Manda Yu
- Institute of Plant and Microbial BiologyAcademia SinicaTaipei11529Taiwan
| | - Kira Eilers
- MRC Centre for Molecular Bacteriology and Infection, Department of Life SciencesImperial College LondonLondonSW7 2AZUK
| | - Yi‐Chieh Wang
- Institute of Plant and Microbial BiologyAcademia SinicaTaipei11529Taiwan
| | - Erh‐Min Lai
- Institute of Plant and Microbial BiologyAcademia SinicaTaipei11529Taiwan
| | - Alain Filloux
- MRC Centre for Molecular Bacteriology and Infection, Department of Life SciencesImperial College LondonLondonSW7 2AZUK
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29
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Li Y, Cao S, Zhang L, Yuan J, Zhao Q, Wen Y, Wu R, Huang X, Yan Q, Huang Y, Ma X, Han X, Miao C, Wen X. A requirement of TolC1 for effective survival, colonization and pathogenicity of Actinobacillus pleuropneumoniae. Microb Pathog 2019; 134:103596. [PMID: 31212036 DOI: 10.1016/j.micpath.2019.103596] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Revised: 06/11/2019] [Accepted: 06/11/2019] [Indexed: 01/18/2023]
Abstract
To establish infection in the host, pathogens have evolved sophisticated systems to cope with environmental conditions and to protect cells against host immunity. TolC is the outer membrane channel component of type 1 secretion systems and multidrug efflux pumps that plays critical roles during the infection process in many pathogens. However, little is known about the exact roles of TolC1 in the pathogenicity of A. pleuropneumoniae, an etiological agent of the porcine contagious pleuropneumoniae that causes severe respiratory disease. In this study, deletion of tolC1 causes apparent ultrastructural defects in A. pleuropneumoniae cell examined by transmission electron microscopy. The tolC1 mutant is hypersensitivity to oxidative, osmotic and acid challenges by in vitro stress assays. Analysis on secreted proteins shows that the excretion of ApxIIA and an ApxIVA-like protein, ApxIVA-S, is abolished in the absence of TolC1. This result confirms the essential role of TolC1 in the secretion of Apx toxins and this is the first identification of an ApxIVA-like protein in in vitro culture of A. pleuropneumoniae. Besides, disruption of TolC1 leads to a significant attenuation of virulence in mice by an intraperitoneal route of A. pleuropneumoniae. The basis for the attenuation is further investigated using a mouse intranasal infection model, which reveals an impaired ability to colonize and induce lesions in the lungs for the loss of TolC1 of A. pleuropneumoniae. In conclusion, our findings demonstrate significant roles of TolC1 in facilitating bacterial survival in hostile conditions, maximum colonization as well as pathogenicity during the infection of A. pleuropneumoniae.
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Affiliation(s)
- Ying Li
- Department of Immunology, School of Basic Medical Science, Southwest Medical University, No. 319 Zhongshan Road, Luzhou, Sichuan, China; Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Sanjie Cao
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China.
| | - Luhua Zhang
- Department of Pathogenic Biology, School of Basic Medical Science, Southwest Medical University, No. 319 Zhongshan Road, Luzhou, Sichuan, China
| | - Jianlin Yuan
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Qin Zhao
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Yiping Wen
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Rui Wu
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Xiaobo Huang
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Qigui Yan
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Yong Huang
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Xiaoping Ma
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Xinfeng Han
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Chang Miao
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China
| | - Xintian Wen
- Research Center of Swine Diseases, College of Veterinary Medicine, Sichuan Agricultural University, No. 211 Huimin Road, Chengdu, Sichuan, China.
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30
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Immunogenicity and protective efficacy of mucosal delivery of recombinant hcp of Campylobacter jejuni Type VI secretion system (T6SS) in chickens. Mol Immunol 2019; 111:182-197. [PMID: 31078054 DOI: 10.1016/j.molimm.2019.04.016] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Revised: 02/05/2019] [Accepted: 04/23/2019] [Indexed: 12/30/2022]
Abstract
The type VI secretion system (T6SS) has recently emerged as a new pattern of protein secretions in Campylobacter jejuni (C. jejuni). Within the T6SS cluster, hemolysin co-regulated protein (hcp) is considered as a hallmark of functional T6SS and holds key role in bacterial virulence. As poultry is the primary reservoir of C. jejuni and the major sources for human infection, we evaluated the capacity of recombinant hcp (rhcp) immunization in blocking C. jejuni colonization in chickens with an aim to control bacterial transmission to humans via poultry food chain. Considering the mucosal route is the primary portal for C. jejuni entry and gut mucosa offers the apposite site for C. jejuni adherence, we investigated the immune-protective potential of intra-gastric administration of rhcp using chitosan-based nanoparticles. To achieve this goal, full length coding sequence of hcp gene from C. jejuni was cloned and expressed in E. coli. Purified rhcp was entrapped in chitosan-Sodium tripolyphosphate nanoparticles (CS-TPP NPs) and orally gavaged in chickens. Our results suggest that intra-gastric immunization of CS-TPP-rhcp induces consistent and steady increase in intestinal (sIgA) and systemic antibody (IgY) response against rhcp with significant reduction in cecal load of C. jejuni. The protection afforded by rhcp associated cellular responses with Th1 and Th17 profile in terms of increased expression of NFkB, IL-1β, IL-8, IL-6, IFN-γ and IL-17 A genes. Though systemic immunization of rhcp with IFA resulting in a robust systemic (IgY) and local (sIgA) antibody response, mucosal administration of rhcp loaded CS-TPP NPs was found to be superior in terms of bacterial clearance. Altogether, present study suggests that chitosan based intra-gastric delivery of rhcp have several advantages over the injectable composition and could be a promising vaccine approach to effectively control C. jejuni colonization in chickens.
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Masum MMI, Siddiqa MM, Ali KA, Zhang Y, Abdallah Y, Ibrahim E, Qiu W, Yan C, Li B. Biogenic Synthesis of Silver Nanoparticles Using Phyllanthus emblica Fruit Extract and Its Inhibitory Action Against the Pathogen Acidovorax oryzae Strain RS-2 of Rice Bacterial Brown Stripe. Front Microbiol 2019; 10:820. [PMID: 31110495 PMCID: PMC6501729 DOI: 10.3389/fmicb.2019.00820] [Citation(s) in RCA: 119] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2019] [Accepted: 04/01/2019] [Indexed: 12/05/2022] Open
Abstract
Biogenic synthesis of silver nanoparticles (AgNPs) using plants has become a promising substitute to the conventional chemical synthesis method. In this study, we report low-cost, green synthesis of AgNPs using fresh fruit extract of Phyllanthus emblica. The biosynthesized AgNPs was confirmed and characterized by analysis of spectroscopy profile of the UV-visible and Energy dispersive spectrophotometer, Fourier transform infrared, X-ray diffraction pattern, and electron microscopy images examination. UV-visible spectra showed a surface resonance peak of 430 nm corresponding to the formation of AgNPs, and FTIR spectra confirmed the involvement of biological molecules in AgNPs synthesis. In spherical AgNPs, the particle size ranged from 19.8 to 92.8 nm and the average diameter was 39 nm. Synthesized nanoparticles at 20 μg/ml showed remarkable antimicrobial activity in vitro against the pathogen Acidovorax oryzae strain RS-2 of rice bacterial brown stripe, while 62.41% reduction in OD600 value was observed compared to the control. Moreover, the inhibitory efficiency of AgNPs increased with the increase of incubation time. Furthermore, AgNPs not only disturbed biofilm formation and swarming ability but also increased the secretion of effector Hcp in strain RS-2, resulting from damage to the cell membrane, which was substantiated by TEM images and live/dead cell staining result. Overall, this study suggested that AgNPs can be an attractive and eco-friendly candidate to control rice bacterial disease.
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Affiliation(s)
- Md. Mahidul Islam Masum
- State Key Laboratory of Rice Biology and Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
- Department of Plant Pathology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur, Bangladesh
| | | | - Khattak Arif Ali
- State Key Laboratory of Rice Biology and Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yang Zhang
- State Key Laboratory of Rice Biology and Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Yasmine Abdallah
- State Key Laboratory of Rice Biology and Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Ezzeldin Ibrahim
- State Key Laboratory of Rice Biology and Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Wen Qiu
- State Key Laboratory of Rice Biology and Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
| | - Chenqi Yan
- Institute of Biotechnology, Ningbo Academy of Agricultural Sciences, Ningbo, China
| | - Bin Li
- State Key Laboratory of Rice Biology and Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou, China
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Zong B, Zhang Y, Wang X, Liu M, Zhang T, Zhu Y, Zheng Y, Hu L, Li P, Chen H, Tan C. Characterization of multiple type-VI secretion system (T6SS) VgrG proteins in the pathogenicity and antibacterial activity of porcine extra-intestinal pathogenic Escherichia coli. Virulence 2019; 10:118-132. [PMID: 30676217 PMCID: PMC6363058 DOI: 10.1080/21505594.2019.1573491] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Porcine extra-intestinal pathogenic Escherichia coli (ExPEC) causes great economic losses to the pig industry and poses a serious threat to public health worldwide. Some secreted virulence factors have been reported to be involved in the pathogenicity of the infection caused by ExPEC. Type-VI secretion system (T6SS) is discovered in many Gram-negative bacteria and contributes to the virulence of pathogenic bacteria. Valine-glycine repeat protein G (VgrG) has been reported as an important component of the functional T6SS. In our previous studies, a functional T6SS was identified in porcine ExPEC strain PCN033. Further analysis of the PCN033 genome identified two putative vgrGs genes (vgrG1 and 0248) located inside T6SS cluster and another two (vgrG2 and 1588) outside it. This study determined the function of the four putative VgrG proteins by constructing a series of mutants and complemented strains. In vitro, the VgrG1 protein was observed to be involved in the antibacterial ability and the interactions with cells. The animal model experiment showed that the deletion of vgrG1 significantly led to the decrease in the multiplication capacity of PCN033. However, the deletion of 0248 and/or the deletion of vgrG2 and 1588 had no effect on the pathogenicity of PCN033. The study of four putative VgrGs in PCN033 indicated that only VgrG1 plays an important role in the interaction between PCN033 and other bacteria or host cells. This study can provide a novel perspective to the pathogenesis of PCN033 and lay the foundation for discovering potential T6SS effectors.
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Affiliation(s)
- Bingbing Zong
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , Hubei , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , Hubei , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , Hubei , China.,d International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China , Wuhan , Hubei , China
| | - Yanyan Zhang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , Hubei , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , Hubei , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , Hubei , China.,d International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China , Wuhan , Hubei , China
| | - Xiangru Wang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , Hubei , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , Hubei , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , Hubei , China.,d International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China , Wuhan , Hubei , China
| | - Manli Liu
- e Hubei Biopesticide Engineering Research Centre , Hubei Academy of Agricultural Sciences , Wuhan Hubei , China
| | - Tongchao Zhang
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , Hubei , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , Hubei , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , Hubei , China.,d International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China , Wuhan , Hubei , China
| | - Yongwei Zhu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , Hubei , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , Hubei , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , Hubei , China.,d International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China , Wuhan , Hubei , China
| | - Yucheng Zheng
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , Hubei , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , Hubei , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , Hubei , China.,d International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China , Wuhan , Hubei , China
| | - Linlin Hu
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , Hubei , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , Hubei , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , Hubei , China.,d International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China , Wuhan , Hubei , China
| | - Pei Li
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , Hubei , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , Hubei , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , Hubei , China.,d International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China , Wuhan , Hubei , China
| | - Huanchun Chen
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , Hubei , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , Hubei , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , Hubei , China.,d International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China , Wuhan , Hubei , China
| | - Chen Tan
- a State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine , Huazhong Agricultural University , Wuhan , Hubei , China.,b Key Laboratory of Preventive Veterinary Medicine in Hubei Province , The Cooperative Innovation Center for Sustainable Pig Production , Wuhan , Hubei , China.,c Key Laboratory of Development of Veterinary Diagnostic Products , Ministry of Agriculture of the People's Republic of China , Wuhan , Hubei , China.,d International Research Center for Animal Disease, Ministry of Science and Technology of the People's Republic of China , Wuhan , Hubei , China
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Ma L, Zhou L, Lin J, Ji J, Wang Y, Jiang H, Shen X, Lu Z. Manipulation of the silkworm immune system by a metalloprotease from the pathogenic bacterium Pseudomonas aeruginosa. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 90:176-185. [PMID: 30261235 PMCID: PMC6204220 DOI: 10.1016/j.dci.2018.09.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Revised: 09/22/2018] [Accepted: 09/23/2018] [Indexed: 05/15/2023]
Abstract
Antimicrobial peptide (AMP) production and melanization are two key humoral immune responses in insects. Induced synthesis of AMPs results from Toll and IMD signal transduction whereas melanization depends on prophenoloxidase (PPO) activation system. During invasion, pathogens produce toxins and other virulent factors to counteract host immune responses. Here we show that the pathways leading to PPO activation and AMP synthesis in the silkworm Bombyx mori are affected by a metalloprotease, named elastase B, secreted by Pseudomonas aeruginosa (PAO1). The metalloprotease gene (lasB) was expressed shortly after PAO1 cells had been injected into the larval silkworm hemocoel, leading to an increase of elastase activity. Injection of the purified PAO1 elastase B into silkworm hemolymph compromised PPO activation. In contrast, the protease caused a level increase of gloverin, an AMP in the hemolymph. To verify our results obtained using the purified elastase B, we infected B. mori with PAO1 ΔlasB mutant and found that PO activity in hemolymph of the PAO1 ΔlasB-infected larvae was significantly higher than that in the wild type-infected. The mutant-inhabited hemolymph had lower levels of gloverin and antimicrobial activity. PAO1 ΔlasB showed a decreased viability in the silkworm hemolymph whereas the host had a lower mortality. In addition, the effects caused by the ΔlasB mutant were restored by a complementary strain. These data collectively indicated that the elastase B produced by PAO1 is an important virulent factor that manipulates the silkworm immune system during infection.
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Affiliation(s)
- Li Ma
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Lizhen Zhou
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jinshui Lin
- Department of Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Jiuyuan Ji
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Yang Wang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Haobo Jiang
- Department of Entomology and Plant Pathology, Oklahoma State University, Stillwater, OK, 74078, USA
| | - Xihui Shen
- Department of Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Zhiqiang Lu
- Department of Entomology, College of Plant Protection, Northwest A&F University, Yangling, Shaanxi 712100, China.
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34
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Groenewold MK, Hebecker S, Fritz C, Czolkoss S, Wiesselmann M, Heinz DW, Jahn D, Narberhaus F, Aktas M, Moser J. Virulence of Agrobacterium tumefaciens requires lipid homeostasis mediated by the lysyl-phosphatidylglycerol hydrolase AcvB. Mol Microbiol 2018; 111:269-286. [PMID: 30353924 DOI: 10.1111/mmi.14154] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2018] [Indexed: 12/24/2022]
Abstract
Agrobacterium tumefaciens transfers oncogenic T-DNA via the type IV secretion system (T4SS) into plants causing tumor formation. The acvB gene encodes a virulence factor of unknown function required for plant transformation. Here we specify AcvB as a periplasmic lysyl-phosphatidylglycerol (L-PG) hydrolase, which modulates L-PG homeostasis. Through functional characterization of recombinant AcvB variants, we showed that the C-terminal domain of AcvB (residues 232-456) is sufficient for full enzymatic activity and defined key residues for catalysis. Absence of the hydrolase resulted in ~10-fold increase in L-PG in Agrobacterium membranes and abolished T-DNA transfer and tumor formation. Overproduction of the L-PG synthase gene (lpiA) in wild-type A. tumefaciens resulted in a similar increase in the L-PG content (~7-fold) and a virulence defect even in the presence of intact AcvB. These results suggest that elevated L-PG amounts (either by overproduction of the synthase or absence of the hydrolase) are responsible for the virulence phenotype. Gradually increasing the L-PG content by complementation with different acvB variants revealed that cellular L-PG levels above 3% of total phospholipids interfere with T-DNA transfer. Cumulatively, this study identified AcvB as a novel virulence factor required for membrane lipid homeostasis and T-DNA transfer.
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Affiliation(s)
- Maike K Groenewold
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany
| | - Stefanie Hebecker
- Institute for Microbiology, Technische Universität Braunschweig, 38106, Braunschweig, Germany
| | - Christiane Fritz
- Lehrstuhl für Biologie der Mikroorganismen, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Simon Czolkoss
- Lehrstuhl für Biologie der Mikroorganismen, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Milan Wiesselmann
- Institute for Microbiology, Technische Universität Braunschweig, 38106, Braunschweig, Germany
| | - Dirk W Heinz
- Structure and Function of Proteins, Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany
| | - Dieter Jahn
- Institute for Microbiology, Technische Universität Braunschweig, 38106, Braunschweig, Germany
| | - Franz Narberhaus
- Lehrstuhl für Biologie der Mikroorganismen, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Meriyem Aktas
- Lehrstuhl für Biologie der Mikroorganismen, Ruhr-Universität Bochum, 44780, Bochum, Germany
| | - Jürgen Moser
- Institute for Microbiology, Technische Universität Braunschweig, 38106, Braunschweig, Germany
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Ding X, Zhang Q, Wang H, Quan G, Zhang D, Ren W, Liao Y, Xia P, Zhu G. The different roles of hcp 1 and hcp 2 of the type VI secretion system in Escherichia coli strain CE129. J Basic Microbiol 2018; 58:938-946. [PMID: 30247772 DOI: 10.1002/jobm.201800156] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 07/28/2018] [Accepted: 07/31/2018] [Indexed: 01/15/2023]
Abstract
Type VI secretion system (T6SS) is a secretory system found in Gram-negative bacteria. One of the main structures for T6SS is Hcp (hemolysin co-regulation protein) pipeline. To investigate the role of Hcp major sub-unit genes hcp1 and hcp2 , we deleted hcp1 and hcp2 genes for constructing the in-frame gene deletion mutants. The properties of biofilm formation and the adhesion to chicken embryo fibroblasts cells (DF1 cells) were reduced in the hcp2 mutant. The knockout of hcp1 and hcp2 genes reduced the ability of the avian pathogenic Escherichia coli (APEC) strain CE129 to infect developing chicken embryos. The expression of quorum sensing (QS)-associated genes luxS, lsrR, and pfs were down-regulated in the hcp1 mutant, and the expression of type 1 fimbriae gene fimA and the adhesion-related genes fimC and papC were decreased in the hcp2 mutant, as well as the expression of anti-serum survival factor genes ompA and iss were inhibited in both hcp1 and hcp2 mutants. These results described above from this study help to further elaborate the role of HCP in APEC.
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Affiliation(s)
- Xueyan Ding
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Qi Zhang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Heng Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China
| | - Guomei Quan
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Dong Zhang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Wenkai Ren
- Guangdong Provincial Key Laboratory of Animal Nutrition Control, Institute of Subtropical Animal Nutrition and Feed, College of Animal Science, South China Agricultural University, Guangzhou, China
| | - Yuexia Liao
- Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Pengpeng Xia
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
| | - Guoqiang Zhu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, China.,Jiangsu Co-Innovation Center for Important Animal Infectious Diseases and Zoonoses, Yangzhou, China.,Joint International Research Laboratory of Agriculture and Agri-Product Safety of Ministry of Education of China, Yangzhou University, Yangzhou, China
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Lin HH, Huang HM, Yu M, Lai EM, Chien HL, Liu CT. Functional Exploration of the Bacterial Type VI Secretion System in Mutualism: Azorhizobium caulinodans ORS571-Sesbania rostrata as a Research Model. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2018. [PMID: 29516754 DOI: 10.1094/mpmi-01-18-0026-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The bacterial type VI secretion system (T6SS) has been considered the armed force of bacteria because it can deliver toxin effectors to prokaryotic or eukaryotic cells for survival and fitness. Although many legume symbiotic rhizobacteria encode T6SS in their genome, the biological function of T6SS in these bacteria is still unclear. To elucidate this issue, we used Azorhizobium caulinodans ORS571 and its symbiotic host Sesbania rostrata as our research model. By using T6SS gene deletion mutants, we found that T6SS provides A. caulinodans with better symbiotic competitiveness when coinfected with a T6SS-lacking strain, as demonstrated by two independent T6SS-deficient mutants. Meanwhile, the symbiotic effectiveness was not affected by T6SS because the nodule phenotype, nodule size, and nodule nitrogen-fixation ability did not differ between the T6SS mutants and the wild type when infected alone. Our data also suggest that under several lab culture conditions tested, A. caulinodans showed no T6SS-dependent interbacterial competition activity. Therefore, instead of being an antihost or antibacterial weapon of the bacterium, the T6SS in A. caulinodans ORS571 seems to participate specifically in symbiosis by increasing its symbiotic competitiveness.
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Affiliation(s)
- Hsiao-Han Lin
- 1 Institute of Biotechnology, National Taiwan University, No. 81, Chang-Xing St., Taipei 10617, Taiwan
- 2 Institute of Plant and Microbial Biology, Academia Sinica, No. 128 Section 2, Academia Rd., Nankang, Taipei 11529, Taiwan; and
| | - Hsin-Mei Huang
- 1 Institute of Biotechnology, National Taiwan University, No. 81, Chang-Xing St., Taipei 10617, Taiwan
| | - Manda Yu
- 2 Institute of Plant and Microbial Biology, Academia Sinica, No. 128 Section 2, Academia Rd., Nankang, Taipei 11529, Taiwan; and
| | - Erh-Min Lai
- 2 Institute of Plant and Microbial Biology, Academia Sinica, No. 128 Section 2, Academia Rd., Nankang, Taipei 11529, Taiwan; and
| | - Hsiao-Lin Chien
- 1 Institute of Biotechnology, National Taiwan University, No. 81, Chang-Xing St., Taipei 10617, Taiwan
| | - Chi-Te Liu
- 1 Institute of Biotechnology, National Taiwan University, No. 81, Chang-Xing St., Taipei 10617, Taiwan
- 3 Agricultural Biotechnology Research Center, Academia Sinica
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Ma J, Sun M, Pan Z, Song W, Lu C, Yao H. Three Hcp homologs with divergent extended loop regions exhibit different functions in avian pathogenic Escherichia coli. Emerg Microbes Infect 2018; 7:49. [PMID: 29593238 PMCID: PMC5874247 DOI: 10.1038/s41426-018-0042-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2017] [Revised: 01/22/2018] [Accepted: 01/23/2018] [Indexed: 11/17/2022]
Abstract
Type VI secretion systems (T6SSs) contribute to the pathogenicity of avian pathogenic Escherichia coli (APEC), one of the leading causative agents of sepsis and meningitis in poultry. The Hcp protein is a core component of the T6SS tail tube and acts as an exported receptor and a chaperone of effectors. In this study, four distinct Hcp types (Ia, Ib, IIa, and IIb) were designated in Gram-negative bacteria, three of which were widely distributed in APEC. We detected divergence in transcription levels among three hcp clusters in 50% duck serum and demonstrated that hcp1 was upregulated by relieving Fur repression. Further analyses revealed that the host serum could activate the hcp2B operon by H-NS derepression to transcribe the downstream xmtU/xmtV pair for inter-bacterial antagonism. Notably, in a structural analysis based on the genetic classification, Hcp proteins exhibited significant differences in the extended loop regions, suggesting that these regions were related to their functional properties. Indeed, the variant region Vs2 (Loop L2, 3) in Hcp1 and Hcp2B was essential for the delivery of antibacterial effectors and the inhibition of macrophage phagocytosis. Further analyses using a duck model indicated that these Hcps play different roles in the pathogenic processes of APEC and immunoprotection. These results indicated that the functional differentiation of Hcp homologs was driven by differences in transcriptional regulation, extended loop regions, and effector delivery.
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Affiliation(s)
- Jiale Ma
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China
| | - Min Sun
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China
| | - Zihao Pan
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China
| | - Wenchao Song
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China
| | - Chengping Lu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China.,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China
| | - Huochun Yao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, 210095, China. .,Key Lab of Animal Bacteriology, Ministry of Agriculture, Nanjing, 210095, China.
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Lin JS, Pissaridou P, Wu HH, Tsai MD, Filloux A, Lai EM. TagF-mediated repression of bacterial type VI secretion systems involves a direct interaction with the cytoplasmic protein Fha. J Biol Chem 2018; 293:8829-8842. [PMID: 29599293 PMCID: PMC5995506 DOI: 10.1074/jbc.ra117.001618] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 03/09/2018] [Indexed: 01/09/2023] Open
Abstract
The bacterial type VI secretion system (T6SS) delivers effectors into eukaryotic host cells or toxins into bacterial competitor for survival and fitness. The T6SS is positively regulated by the threonine phosphorylation pathway (TPP) and negatively by the T6SS-accessory protein TagF. Here, we studied the mechanisms underlying TagF-mediated T6SS repression in two distinct bacterial pathogens, Agrobacterium tumefaciens and Pseudomonas aeruginosa. We found that in A. tumefaciens, T6SS toxin secretion and T6SS-dependent antibacterial activity are suppressed by a two-domain chimeric protein consisting of TagF and PppA, a putative phosphatase. Remarkably, this TagF domain is sufficient to post-translationally repress the T6SS, and this inhibition is independent of TPP. This repression requires interaction with a cytoplasmic protein, Fha, critical for activating T6SS assembly. In P. aeruginosa, PppA and TagF are two distinct proteins that repress T6SS in TPP-dependent and -independent pathways, respectively. P. aeruginosa TagF interacts with Fha1, suggesting that formation of this complex represents a conserved TagF-mediated regulatory mechanism. Using TagF variants with substitutions of conserved amino acid residues at predicted protein–protein interaction interfaces, we uncovered evidence that the TagF–Fha interaction is critical for TagF-mediated T6SS repression in both bacteria. TagF inhibits T6SS without affecting T6SS protein abundance in A. tumefaciens, but TagF overexpression reduces the protein levels of all analyzed T6SS components in P. aeruginosa. Our results indicate that TagF interacts with Fha, which in turn could impact different stages of T6SS assembly in different bacteria, possibly reflecting an evolutionary divergence in T6SS control.
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Affiliation(s)
- Jer-Sheng Lin
- From the Institute of Plant and Microbial Biology and
| | - Panayiota Pissaridou
- the Medical Research Council Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Hsin-Hui Wu
- the Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan and
| | - Ming-Daw Tsai
- the Institute of Biological Chemistry, Academia Sinica, Taipei 11529, Taiwan and
| | - Alain Filloux
- the Medical Research Council Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Imperial College London, London SW7 2AZ, United Kingdom
| | - Erh-Min Lai
- From the Institute of Plant and Microbial Biology and
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Niche Construction and Exploitation by Agrobacterium: How to Survive and Face Competition in Soil and Plant Habitats. Curr Top Microbiol Immunol 2018; 418:55-86. [PMID: 29556826 DOI: 10.1007/82_2018_83] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Agrobacterium populations live in different habitats (bare soil, rhizosphere, host plants), and hence face different environmental constraints. They have evolved the capacity to exploit diverse resources and to escape plant defense and competition from other microbiota. By modifying the genome of their host, Agrobacterium populations exhibit the remarkable ability to construct and exploit the ecological niche of the plant tumors that they incite. This niche is characterized by the accumulation of specific, low molecular weight compounds termed opines that play a critical role in Agrobacterium 's lifestyle. We present and discuss the functions, advantages, and costs associated with this niche construction and exploitation.
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Wu CF, Smith DA, Lai EM, Chang JH. The Agrobacterium Type VI Secretion System: A Contractile Nanomachine for Interbacterial Competition. Curr Top Microbiol Immunol 2018; 418:215-231. [PMID: 29992360 DOI: 10.1007/82_2018_99] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The bacterial type VI secretion system (T6SS) is a contractile nanomachine dedicated to delivering molecules out of bacterial cells. T6SS-encoding loci are in the genome sequences of many Gram-negative bacteria, and T6SS has been implicated in a plethora of roles. In the majority of cases, the T6SSs deliver effector proteins in a contact-dependent manner to antagonize other bacteria. Current models suggest that the effectors are deployed to influence social interactions in microbial communities. In this chapter, we describe the structure, function, and regulation of the T6SS and its effectors. We provide focus on the T6SS of Agrobacterium tumefaciens, the causative agent of crown gall disease, and relate the role of the T6SS to the ecology of A. tumefaciens.
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Affiliation(s)
- Chih-Feng Wu
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - Delaney A Smith
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, 11529, Taiwan
| | - Jeff H Chang
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR, USA.
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR, USA.
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Bernal P, Llamas MA, Filloux A. Type VI secretion systems in plant-associated bacteria. Environ Microbiol 2017; 20:1-15. [PMID: 29027348 PMCID: PMC5813230 DOI: 10.1111/1462-2920.13956] [Citation(s) in RCA: 126] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Revised: 10/02/2017] [Accepted: 10/05/2017] [Indexed: 11/28/2022]
Abstract
The type VI secretion system (T6SS) is a bacterial nanomachine used to inject effectors into prokaryotic or eukaryotic cells and is thus involved in both host manipulation and interbacterial competition. The T6SS is widespread among Gram‐negative bacteria, mostly within the Proteobacterium Phylum. This secretion system is commonly found in commensal and pathogenic plant‐associated bacteria. Phylogenetic analysis of phytobacterial T6SS clusters shows that they are distributed in the five main clades previously described (group 1–5). The even distribution of the system among commensal and pathogenic phytobacteria suggests that the T6SS provides fitness and colonization advantages in planta and that the role of the T6SS is not restricted to virulence. This manuscript reviews the phylogeny and biological roles of the T6SS in plant‐associated bacteria, highlighting a remarkable diversity both in terms of mechanism and function.
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Affiliation(s)
- Patricia Bernal
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Flowers Building, 1st floor South Kensington Campus, Imperial College London, London SW7 2AZ, UK
| | - María A Llamas
- Department of Environmental Protection, Estación Experimental del Zaidín-Consejo Superior de Investigaciones Científicas, 18008 Granada, Spain
| | - Alain Filloux
- Department of Life Sciences, MRC Centre for Molecular Bacteriology and Infection, Flowers Building, 1st floor South Kensington Campus, Imperial College London, London SW7 2AZ, UK
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Hwang HH, Yu M, Lai EM. Agrobacterium-mediated plant transformation: biology and applications. THE ARABIDOPSIS BOOK 2017; 15:e0186. [PMID: 31068763 PMCID: PMC6501860 DOI: 10.1199/tab.0186] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Plant genetic transformation heavily relies on the bacterial pathogen Agrobacterium tumefaciens as a powerful tool to deliver genes of interest into a host plant. Inside the plant nucleus, the transferred DNA is capable of integrating into the plant genome for inheritance to the next generation (i.e. stable transformation). Alternatively, the foreign DNA can transiently remain in the nucleus without integrating into the genome but still be transcribed to produce desirable gene products (i.e. transient transformation). From the discovery of A. tumefaciens to its wide application in plant biotechnology, numerous aspects of the interaction between A. tumefaciens and plants have been elucidated. This article aims to provide a comprehensive review of the biology and the applications of Agrobacterium-mediated plant transformation, which may be useful for both microbiologists and plant biologists who desire a better understanding of plant transformation, protein expression in plants, and plant-microbe interaction.
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Affiliation(s)
- Hau-Hsuan Hwang
- Department of Life Sciences, National Chung Hsing University, Taichung, Taiwan, 402
| | - Manda Yu
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, 115
| | - Erh-Min Lai
- Institute of Plant and Microbial Biology, Academia Sinica, Taipei, Taiwan, 115
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Masum MMI, Yang Y, Li B, Olaitan OS, Chen J, Zhang Y, Fang Y, Qiu W, Wang Y, Sun G. Role of the Genes of Type VI Secretion System in Virulence of Rice Bacterial Brown Stripe Pathogen Acidovorax avenae subsp. avenae Strain RS-2. Int J Mol Sci 2017; 18:ijms18102024. [PMID: 28934168 PMCID: PMC5666706 DOI: 10.3390/ijms18102024] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 09/09/2017] [Accepted: 09/19/2017] [Indexed: 12/17/2022] Open
Abstract
The Type VI secretion system (T6SS) is a class of macromolecular machine that is required for the virulence of gram-negative bacteria. However, it is still not clear what the role of T6SS in the virulence of rice bacterial brown stripe pathogen Acidovorax avenae subsp. avenae (Aaa) is. The aim of the current study was to investigate the contribution of T6SS in Aaa strain RS2 virulence using insertional deletion mutation and complementation approaches. This strain produced weak virulence but contains a complete T6SS gene cluster based on a genome-wide analysis. Here we compared the virulence-related phenotypes between the wild-type (RS-2) and 25 T6SS mutants, which were constructed using homologous recombination methods. The mutation of 15 T6SS genes significantly reduced bacterial virulence and the secretion of Hcp protein. Additionally, the complemented 7 mutations ΔpppA, ΔclpB, Δhcp, ΔdotU, ΔicmF, ΔimpJ, and ΔimpM caused similar virulence characteristics as RS-2. Moreover, the mutant ΔpppA, ΔclpB, ΔicmF, ΔimpJ and ΔimpM genes caused by a 38.3~56.4% reduction in biofilm formation while the mutants ΔpppA, ΔclpB, ΔicmF and Δhcp resulted in a 37.5~44.6% reduction in motility. All together, these results demonstrate that T6SS play vital roles in the virulence of strain RS-2, which may be partially attributed to the reductions in Hcp secretion, biofilm formation and motility. However, differences in virulence between strain RS-1 and RS-2 suggest that other factors may also be involved in the virulence of Aaa.
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Affiliation(s)
- Md Mahidul Islam Masum
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
- Department of Plant Pathology, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh.
| | - Yingzi Yang
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Bin Li
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Ogunyemi Solabomi Olaitan
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Jie Chen
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Yang Zhang
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Yushi Fang
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Wen Qiu
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, Hangzhou 310058, China.
| | - Yanli Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
| | - Guochang Sun
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, Hangzhou 310021, China.
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Kamber T, Pothier JF, Pelludat C, Rezzonico F, Duffy B, Smits THM. Role of the type VI secretion systems during disease interactions of Erwinia amylovora with its plant host. BMC Genomics 2017; 18:628. [PMID: 28818038 PMCID: PMC5561584 DOI: 10.1186/s12864-017-4010-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 08/02/2017] [Indexed: 12/13/2022] Open
Abstract
Background Type VI secretion systems (T6SS) are widespread among Gram-negative bacteria and have a potential role as essential virulence factors or to maintain symbiotic interactions. Three T6SS gene clusters were identified in the genome of E. amylovora CFBP 1430, of which T6SS-1 and T6SS-3 represent complete T6SS machineries, while T6SS-2 is reduced in its gene content. Results To assess the contribution of T6SSs to virulence and potential transcriptomic changes of E. amylovora CFBP 1430, single and double mutants in two structural genes were generated for T6SS-1 and T6SS-3. Plant assays showed that mutants in T6SS-3 were slightly more virulent in apple shoots while inducing less disease symptoms on apple flowers, indicating that T6SSs have only a minor effect on virulence of E. amylovora CFBP 1430. The mutations led under in vitro conditions to the differential expression of type III secretion systems, iron acquisition, chemotaxis, flagellar, and fimbrial genes. Comparison of the in planta and in vitro transcriptome data sets revealed a common differential expression of three processes and a set of chemotaxis and motility genes. Additional experiments proved that T6SS mutants are impaired in their motility. Conclusion These results suggest that the deletion of T6SSs alters metabolic and motility processes. Nevertheless, the difference in lesion development in apple shoots and flower necrosis of T6SS mutants was indicative that T6SSs influences the disease progression and the establishment of the pathogen on host plants. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-4010-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Tim Kamber
- Agroscope Changins-Wädenswil ACW, Plant Protection Division, 8820, Wädenswil, CH, Switzerland
| | - Joël F Pothier
- Agroscope Changins-Wädenswil ACW, Plant Protection Division, 8820, Wädenswil, CH, Switzerland.,Environmental Genomics and Systems Biology Research Group, Institute of Natural Resource Sciences, Zurich University of Applied Sciences (ZHAW), 8820, Wädenswil, CH, Switzerland
| | - Cosima Pelludat
- Agroscope Changins-Wädenswil ACW, Plant Protection Division, 8820, Wädenswil, CH, Switzerland
| | - Fabio Rezzonico
- Agroscope Changins-Wädenswil ACW, Plant Protection Division, 8820, Wädenswil, CH, Switzerland.,Environmental Genomics and Systems Biology Research Group, Institute of Natural Resource Sciences, Zurich University of Applied Sciences (ZHAW), 8820, Wädenswil, CH, Switzerland
| | - Brion Duffy
- Environmental Genomics and Systems Biology Research Group, Institute of Natural Resource Sciences, Zurich University of Applied Sciences (ZHAW), 8820, Wädenswil, CH, Switzerland
| | - Theo H M Smits
- Agroscope Changins-Wädenswil ACW, Plant Protection Division, 8820, Wädenswil, CH, Switzerland. .,Environmental Genomics and Systems Biology Research Group, Institute of Natural Resource Sciences, Zurich University of Applied Sciences (ZHAW), 8820, Wädenswil, CH, Switzerland.
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45
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Tian Y, Zhao Y, Shi L, Cui Z, Hu B, Zhao Y. Type VI Secretion Systems of Erwinia amylovora Contribute to Bacterial Competition, Virulence, and Exopolysaccharide Production. PHYTOPATHOLOGY 2017; 107:654-661. [PMID: 28421913 DOI: 10.1094/phyto-11-16-0393-r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The type VI secretion system (T6SS) plays a major role in mediating interbacterial competition and might contribute to virulence in plant pathogenic bacteria. However, the role of T6SS in Erwinia amylovora remains unknown. In this study, 33 deletion mutants within three T6SS clusters were generated in E. amylovora strain NCPPB1665. Our results showed that all 33 mutants displayed reduced antibacterial activities against Escherichia coli as compared with that of the wild-type (WT) strain, indicating that Erwinia amylovora T6SS are functional. Of the 33 mutants, 19 exhibited reduced virulence on immature pear fruit as compared with that of the WT strain. Among them, 6, 1, and 12 genes belonged to T6SS-1, T6SS-2, and T6SS-3 clusters, respectively. Interestingly, these 19 mutants also produced less amylovoran or levan or both. These findings suggest that E. amylovora T6SS play a role in bacterial competition and virulence possibly by influencing exopolysaccharide production.
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Affiliation(s)
- Yanli Tian
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
| | - Yuqiang Zhao
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
| | - Linye Shi
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
| | - Zhongli Cui
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
| | - Baishi Hu
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
| | - Youfu Zhao
- First, third, and fifth authors: College of Plant Protection and Key Laboratory of Integrated Management of Crop Diseases and Pests, Ministry of Education, Nanjing Agricultural University, Nanjing 210095, China; second author: Institute of Botany, Jiangsu Province and the Chinese Academy of Sciences (Nanjing Botanical Garden Mem. Sun Yat-Sen), Nanjing 210014, China; fourth author: College of Life Sciences and Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, Nanjing Agricultural University, Nanjing 210095, China; and sixth author: Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana
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Zhao M, Zhang L, Lv S, Zhang C, Wang L, Chen H, Zhou Y, Lou J. IQGAP1 Mediates Hcp1-Promoted Escherichia coli Meningitis by Stimulating the MAPK Pathway. Front Cell Infect Microbiol 2017; 7:132. [PMID: 28469997 PMCID: PMC5395654 DOI: 10.3389/fcimb.2017.00132] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 03/31/2017] [Indexed: 01/14/2023] Open
Abstract
Escherichia coli-induced meningitis remains a life-threatening disease despite recent advances in the field of antibiotics-based therapeutics, necessitating continued research on its pathogenesis. The current study aims to elucidate the mechanism through which hemolysin-coregulated protein 1 (Hcp1) induces the apoptosis of human brain microvascular endothelial cells (HBMEC). Co-immunoprecipitation coupled with mass spectrometric (MS) characterization led to the identification of IQ motif containing GTPase activating protein 1 (IQGAP1) as a downstream target of Hcp1. IQGAP1 was found to be up-regulated by Hcp1 treatment and mediate the stimulation of HBMEC apoptosis. It was shown that Hcp1 could compete against Smurf1 for binding to IQGAP1, thereby rescuing the latter from ubiquitin-dependent degradation. Subsequent study suggested that IQGAP1 could stimulate the MAPK signaling pathway by promoting the phosphorylation of ERK1/2, an effect that was blocked by U0126, an MAPK inhibitor. Furthermore, U0126 also demonstrated therapeutic potential against E. coli meningitis in a mouse model. Taken together, our results suggested the feasibility of targeting the MAPK pathway as a putative therapeutic strategy against bacterial meningitis.
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Affiliation(s)
- Mingna Zhao
- Department of Laboratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong UniversityShanghai, China
| | - Lingfei Zhang
- Center for RNA Research, State Key Laboratory of Molecular Biology-University of Chinese Academy of Sciences, Institute of Biochemistry and Cell Biology Shanghai Institutes for Biological Sciences Chinese Academy of SciencesShanghai, China.,Department of Anatomy, Histology and Embryology, Shanghai Medical College, Fudan UniversityShanghai, China
| | - Shaogang Lv
- Department of Laboratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong UniversityShanghai, China
| | - Chenzi Zhang
- Department of Laboratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong UniversityShanghai, China
| | - Lin Wang
- Department of Laboratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong UniversityShanghai, China
| | - Hong Chen
- Department of Anatomy, Histology and Embryology, Shanghai Medical College, Fudan UniversityShanghai, China
| | - Yan Zhou
- Department of Microbiology and Immunobiology, Harvard Medical SchoolBoston, MA, USA
| | - Jiatao Lou
- Department of Laboratory Medicine, Shanghai Chest Hospital, Shanghai Jiao Tong UniversityShanghai, China
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Qin T, Zhou H, Ren H, Liu W. Distribution of Secretion Systems in the Genus Legionella and Its Correlation with Pathogenicity. Front Microbiol 2017; 8:388. [PMID: 28352254 PMCID: PMC5348487 DOI: 10.3389/fmicb.2017.00388] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 02/24/2017] [Indexed: 12/27/2022] Open
Abstract
The genus Legionella comprises over 60 species, which are important human pathogens. Secretion systems in Legionella pneumophila have been studied extensively because of the essential role of protein secretion in bacterial infection. However, there are few reports describing the secretion systems in non-L. pneumophila species. In this study, we analyzed the distribution of secretion systems in L. pneumophila and 18 species of non-L. pneumophila based on whole genome sequences. A total of 74 whole genome sequences from 19 species of Legionella were analyzed. Type II and IVB secretion systems were detected in all Legionella strains, but the type I secretion systems was restricted to L. pneumophila. The type IVA secretion system was randomly distributed among different species. Furthermore, we found the type VI secretion system in three non-L. pneumophila strains (Legionella cherrii DSM 19213, Legionella dumoffii Tex-KL, and Legionella gormanii ATCC 33297). In population structure analysis, L. pneumophila formed a conservative cluster and was located at the terminal of the evolutionary tree. At the same time, L. pneumophila, especially eight clone groups (named MCGG1–MCGG8), showed higher intracellular growth ability than non-L. pneumophila species. These results suggest that L. pneumophila has acquired additional secretion systems during evolution, resulting in increased pathogenicity.
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Affiliation(s)
- Tian Qin
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious DiseasesHangzhou, China
| | - Haijian Zhou
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and PreventionBeijing, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious DiseasesHangzhou, China
| | - Hongyu Ren
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention Beijing, China
| | - Wenbin Liu
- Novogene Bioinformatics Technology Co. Ltd Beijing, China
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VgrG C terminus confers the type VI effector transport specificity and is required for binding with PAAR and adaptor-effector complex. Proc Natl Acad Sci U S A 2016; 113:E3931-40. [PMID: 27313214 DOI: 10.1073/pnas.1600428113] [Citation(s) in RCA: 115] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Type VI secretion system (T6SS) is a macromolecular machine used by many Gram-negative bacteria to inject effectors/toxins into eukaryotic hosts or prokaryotic competitors for survival and fitness. To date, our knowledge of the molecular determinants and mechanisms underlying the transport of these effectors remains limited. Here, we report that two T6SS encoded valine-glycine repeat protein G (VgrG) paralogs in Agrobacterium tumefaciens C58 specifically control the secretion and interbacterial competition activity of the type VI DNase toxins Tde1 and Tde2. Deletion and domain-swapping analysis identified that the C-terminal extension of VgrG1 specifically confers Tde1 secretion and Tde1-dependent interbacterial competition activity in planta, and the C-terminal variable region of VgrG2 governs this specificity for Tde2. Functional studies of VgrG1 and VgrG2 variants with stepwise deletion of the C terminus revealed that the C-terminal 31 aa (C31) of VgrG1 and 8 aa (C8) of VgrG2 are the molecular determinants specifically required for delivery of each cognate Tde toxin. Further in-depth studies on Tde toxin delivery mechanisms revealed that VgrG1 interacts with the adaptor/chaperone-effector complex (Tap-1-Tde1) in the absence of proline-alanine-alanine-arginine (PAAR) and the VgrG1-PAAR complex forms independent of Tap-1 and Tde1. Importantly, we identified the regions involved in these interactions. Although the entire C31 segment is required for binding with the Tap-1-Tde1 complex, only the first 15 aa of this region are necessary for PAAR binding. These results suggest that the VgrG1 C terminus interacts sequentially or simultaneously with the Tap-1-Tde1 complex and PAAR to govern Tde1 translocation across bacterial membranes and delivery into target cells for antibacterial activity.
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Yin S, Li M, Rao X, Yao X, Zhong Q, Wang M, Wang J, Peng Y, Tang J, Hu F, Zhao Y. Subtilisin-like protease-1 secreted through type IV secretion system contributes to high virulence of Streptococcus suis 2. Sci Rep 2016; 6:27369. [PMID: 27270879 PMCID: PMC4897608 DOI: 10.1038/srep27369] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2015] [Accepted: 05/18/2016] [Indexed: 11/24/2022] Open
Abstract
Streptococcus suis serotype 2 is an emerging zoonotic pathogen that triggered two outbreaks of streptococcal toxic shock syndrome (STSS) in China. Our previous research demonstrated that a type IV secretion system (T4SS) harbored in the 89K pathogenicity island contributes to the pathogenicity of S. suis 2. In the present study, a shotgun proteomics approach was employed to identify the effectors secreted by T4SS in S. suis 2, and surface-associated subtilisin-like protease-1 (SspA-1) was identified as a potential virulence effector. Western blot analysis and pull-down assay revealed that SspA-1 secretion depends on T4SS. Knockout mutations affecting sspA-1 attenuated S. suis 2 and impaired the pathogen’s ability to trigger inflammatory response in mice. And purified SspA-1 induced the secretion of IL-6, TNF-α, and IL-12p70 in THP-1 cells directly. SspA-1 is the first T4SS virulence effector reported in Gram-positive bacteria. Overall, these findings allow us to gain further insights into the pathogenesis of T4SS and STSS.
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Affiliation(s)
- Supeng Yin
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Ming Li
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Xiancai Rao
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Xinyue Yao
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Qiu Zhong
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Min Wang
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Jing Wang
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Yizhi Peng
- Institute of Burn Research, Southwest Hospital, Third Military Medical University, Chongqing, China
| | - Jiaqi Tang
- PLA Research Institute of Clinical Laboratory Medicine, Nanjing general hospital of Nanjing Military command, Nanjing 210002, China
| | - Fuquan Hu
- Department of Microbiology, Third Military Medical University, Chongqing, China
| | - Yan Zhao
- Department of Microbiology, Third Military Medical University, Chongqing, China
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Roles of Hcp family proteins in the pathogenesis of the porcine extraintestinal pathogenic Escherichia coli type VI secretion system. Sci Rep 2016; 6:26816. [PMID: 27229766 PMCID: PMC4882540 DOI: 10.1038/srep26816] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 05/09/2016] [Indexed: 12/21/2022] Open
Abstract
Hcp (hemolysin-coregulated protein) is considered a vital component of the functional T6SS (Type VI Secretion System), which is a newly discovered secretion system. Our laboratory has previously sequenced the whole genome of porcine extraintestinal pathogenic E. coli (ExPEC) strain PCN033, and identified an integrated T6SS encoding three different hcp family genes. In this study, we first identified a functional T6SS in porcine ExPEC strain PCN033, and demonstrated that the Hcp family proteins were involved in bacterial competition and the interactions with other cells. Interestingly, the three Hcp proteins had different functions. Hcp2 functioned predominantly in bacterial competition; all three proteins were involved in the colonization of mice; and Hcp1 and Hcp3 were predominantly contributed to bacterial-eukaryotic cell interactions. We showed an active T6SS in porcine ExPEC strain PCN033, and the Hcp family proteins had different functions in their interaction with other bacteria or host cells.
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