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Yang Q, Dong X, Xie G, Fu S, Zou P, Sun J, Wang Y, Huang J. Comparative genomic analysis unravels the transmission pattern and intra-species divergence of acute hepatopancreatic necrosis disease (AHPND)-causing Vibrio parahaemolyticus strains. Mol Genet Genomics 2019; 294:1007-1022. [PMID: 30968246 DOI: 10.1007/s00438-019-01559-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Accepted: 04/01/2019] [Indexed: 12/19/2022]
Abstract
Acute hepatopancreatic necrosis disease (AHPND) is a recently discovered shrimp disease that has become a severe threat to global shrimp-farming industry. The causing agents of AHPND were identified as Vibrio parahaemolyticus and other vibrios harboring a plasmid encoding binary toxins PirAvp/PirBvp. However, the epidemiological involvement of environmental vibrios in AHPND is poorly understood. In this study, with an aim to reveal the possible transmission route of AHPND-causing V. parahaemolyticus, we sequenced and analyzed the genomes of four pairs of V. parahaemolyticus strains from four representative regions of shrimp farming in China, each including one strain isolated from diseased shrimp during an AHPND outbreak and one strain isolated from sediment before AHPND outbreaks. Our results showed that all the four shrimp-isolated and three of the sediment-isolated strains encode and secret PirAvp/PirBvp toxins and, therefore, are AHPND-causing strains. In silico multilocus sequence typing and high-resolution phylogenomic analysis based on single-nucleotide polymorphisms, as well as comparison of genomic loci in association with prophages and capsular polysaccharides (CPSs) consistently pointed to a close genetic relationship between the shrimp- and sediment-isolated strains obtained from the same region. In addition, our analyses revealed that the sequences associated with prophages, CPSs, and type VI secretion system-1 are highly divergent among strains from different regions, implying that these genes may play vital roles in environmental adaptation for AHPND-causing V. parahaemolyticus and thereby be potential targets for AHPND control. Summing up, this study provides the first direct evidence regarding the transmission route of AHPND-causing V. parahaemolyticus and underscores that V. parahaemolyticus in shrimp are most likely originated from local environment. The importance of environmental disinfection measures in shrimp farming was highlighted.
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Affiliation(s)
- Qian Yang
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Xuan Dong
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Guosi Xie
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Songzhe Fu
- College of Marine Technology and Environment, Dalian Ocean University, Dalian, China.
| | - Peizhuo Zou
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Jing Sun
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China
| | - Yi Wang
- College of Marine Technology and Environment, Dalian Ocean University, Dalian, China
| | - Jie Huang
- Laboratory for Marine Fisheries Science and Food Production Processes, Qingdao National Laboratory for Marine Science and Technology, Key Laboratory of Maricultural Organism Disease Control, Ministry of Agriculture and Rural Affairs, Qingdao Key Laboratory of Mariculture Epidemiology and Biosecurity, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, China.
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52
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Ben-Yaakov R, Salomon D. The regulatory network of Vibrio parahaemolyticus type VI secretion system 1. Environ Microbiol 2019; 21:2248-2260. [PMID: 30882997 PMCID: PMC6618117 DOI: 10.1111/1462-2920.14594] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 02/13/2019] [Accepted: 03/14/2019] [Indexed: 12/15/2022]
Abstract
Type VI secretion systems (T6SSs) are widespread, tightly regulated, protein delivery apparatuses used by Gram‐negative bacteria to outcompete their neighbours. The pathogen, Vibrio parahaemolyticus, encodes two T6SSs. These T6SSs are differentially regulated by external conditions. T6SS1, an antibacterial system predominantly found in pathogenic isolates, requires warm marine‐like conditions and surface sensing for activation. The regulatory network that governs this activation is not well understood. In this work, we devised a screening methodology that allows us to easily monitor the outcome of bacterial competitions and thus to identify mutants that are defective in T6SS1‐mediated bacterial killing. The methodology, termed Bacterial Competition Fluorescence (BaCoF), relies on detection of a fluorescent signal as an indicator of the survival and growth of a T6SS‐sensitive, GFP‐expressing prey that has been co‐cultured with mutants derived from a T6SS+ attacker of interest. Using BaCoF, we screened a random transposon insertion mutant library and identified genes required for V. parahaemolyticus T6SS1 activation, among them TfoY and Tmk. We used epistasis experiments to determine the relationships between the newly identified components and other regulators that were previously described. Thus, we present here a detailed biological understanding of the T6SS1 regulatory network.
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Affiliation(s)
- Rotem Ben-Yaakov
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Dor Salomon
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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53
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Li L, Meng H, Gu D, Li Y, Jia M. Molecular mechanisms of Vibrio parahaemolyticus pathogenesis. Microbiol Res 2019; 222:43-51. [PMID: 30928029 DOI: 10.1016/j.micres.2019.03.003] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/27/2019] [Accepted: 03/07/2019] [Indexed: 12/12/2022]
Abstract
Vibrio parahaemolyticus is a Gram-negative halophilic bacterium that is mainly distributed in the seafood such as fish, shrimps and shellfish throughout the world. V. parahaemolyticus can cause diseases in marine aquaculture, leading to huge economic losses to the aquaculture industry. More importantly, it is also the leading cause of seafood-borne diarrheal disease in humans worldwide. With the development of animal model, next-generation sequencing as well as biochemical and cell biological technologies, deeper understanding of the virulence factors and pathogenic mechanisms of V. parahaemolyticus has been gained. As a globally transmitted pathogen, the pathogenicity of V. parahaemolyticus is closely related to a variety of virulence factors. This article comprehensively reviewed the molecular mechanisms of eight types of virulence factors: hemolysin, type III secretion system, type VI secretion system, adhesion factor, iron uptake system, lipopolysaccharide, protease and outer membrane proteins. This review comprehensively summarized our current understanding of the virulence factors in V. parahaemolyticus, which are potentially new targets for the development of therapeutic and preventive strategies.
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Affiliation(s)
- Lingzhi Li
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Hongmei Meng
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Dan Gu
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China.
| | - Yang Li
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
| | - Mengdie Jia
- Jiangsu Key Laboratory of Zoonosis/Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, 225009, China; Joint International Research Laboratory of Agriculture and Agri-Product Safety/Key Laboratory of Prevention and Control of Biological Hazard Factors (Animal Origin) for Agrifood Safety and Quality, The Ministry of Education of China, Yangzhou University, Yangzhou, 225009, China
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54
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Dar Y, Salomon D, Bosis E. The Antibacterial and Anti-Eukaryotic Type VI Secretion System MIX-Effector Repertoire in Vibrionaceae. Mar Drugs 2018; 16:md16110433. [PMID: 30400344 PMCID: PMC6267618 DOI: 10.3390/md16110433] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 10/31/2018] [Accepted: 11/01/2018] [Indexed: 12/12/2022] Open
Abstract
Vibrionaceae is a widespread family of aquatic bacteria that includes emerging pathogens and symbionts. Many Vibrionaceae harbor a type VI secretion system (T6SS), which is a secretion apparatus used to deliver toxins, termed effectors, into neighboring cells. T6SSs mediate both antibacterial and anti-eukaryotic activities. Notably, antibacterial effectors are encoded together with a gene that encodes a cognate immunity protein so as to antagonize the toxicity of the effector. The MIX (Marker for type sIX effectors) domain has been previously defined as a marker of T6SS effectors carrying polymorphic C-terminal toxins. Here, we set out to identify the Vibrionaceae MIX-effector repertoire and to analyze the various toxin domains they carry. We used a computational approach to search for the MIX-effectors in the Vibrionaceae genomes, and grouped them into clusters based on the C-terminal toxin domains. We classified MIX-effectors as either antibacterial or anti-eukaryotic, based on the presence or absence of adjacent putative immunity genes, respectively. Antibacterial MIX-effectors carrying pore-forming, phospholipase, nuclease, peptidoglycan hydrolase, and protease activities were found. Furthermore, we uncovered novel virulence MIX-effectors. These are encoded by “professional MIXologist” strains that employ a cocktail of antibacterial and anti-eukaryotic MIX-effectors. Our findings suggest that certain Vibrionaceae adapted their antibacterial T6SS to mediate interactions with eukaryotic hosts or predators.
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Affiliation(s)
- Yasmin Dar
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.
| | - Dor Salomon
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv 6997801, Israel.
| | - Eran Bosis
- Department of Biotechnology Engineering, ORT Braude College of Engineering, Karmiel 2161002, Israel.
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55
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Kumar V, Baruah K, Nguyen DV, Smagghe G, Vossen E, Bossier P. Phloroglucinol-Mediated Hsp70 Production in Crustaceans: Protection against Vibrio parahaemolyticus in Artemia franciscana and Macrobrachium rosenbergii. Front Immunol 2018; 9:1091. [PMID: 29872432 PMCID: PMC5972194 DOI: 10.3389/fimmu.2018.01091] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 05/01/2018] [Indexed: 02/03/2023] Open
Abstract
The halophilic aquatic bacterium, Vibrio parahaemolyticus, is an important aquatic pathogen, also capable of causing acute hepatopancreatic necrosis disease (AHPND) in shrimp resulting in significant economic losses. Therefore, there is an urgent need to develop anti-infective strategies to control AHPND. The gnotobiotic Artemia model is used to establish whether a phenolic compound phloroglucinol is effective against the AHPND strain V. parahaemolyticus MO904. We found that pretreatment with phloroglucinol, at an optimum concentration (30 µM), protects axenic brine shrimp larvae against V. parahaemolyticus infection and induced heat shock protein 70 (Hsp70) production (twofolds or more) as compared with the control. We further demonstrated that the Vibrio-protective effect of phloroglucinol was caused by its prooxidant effect and is linked to the induction of Hsp70. In addition, RNA interference confirms that phloroglucinol-induced Hsp70 mediates the survival of brine shrimp larvae against V. parahaemolyticus infection. The study was validated in xenic Artemia model and in a Macrobrachium rosenbergii system. Pretreatment of xenic brine shrimp larvae (30 µM) and Macrobrachium larvae (5 µM) with phloroglucinol increases the survival of xenic brine shrimp and Macrobrachium larvae against subsequent V. parahaemolyticus challenge. Taken together, our study provides substantial evidence that the prooxidant activity of phloroglucinol induces Hsp70 production protecting brine shrimp, A. franciscana, and freshwater shrimp, M. rosenbergii, against the AHPND V. parahaemolyticus strain MO904. Probably, phloroglucinol treatment might become part of a holistic strategy to control AHPND in shrimp.
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Affiliation(s)
- Vikash Kumar
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium.,ICAR-Central Inland Fisheries Research Institute (CIFRI), Barrackpore, India
| | - Kartik Baruah
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Dung Viet Nguyen
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Guy Smagghe
- Department of Crop Protection, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Els Vossen
- Laboratory of Animal Nutrition and Animal Product Quality, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Peter Bossier
- Laboratory of Aquaculture & Artemia Reference Center, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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56
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Ng TH, Lu CW, Lin SS, Chang CC, Tran LH, Chang WC, Lo CF, Wang HC. The Rho signalling pathway mediates the pathogenicity of AHPND-causing V. parahaemolyticus in shrimp. Cell Microbiol 2018; 20:e12849. [PMID: 29624825 DOI: 10.1111/cmi.12849] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Revised: 03/16/2018] [Accepted: 03/28/2018] [Indexed: 01/14/2023]
Abstract
An emerging bacterial disease, acute hepatopancreatic necrosis disease (AHPND), is caused by strains of Vibrio parahaemolyticus with an additional AHPND-associated plasmid pVA1 encoding a virulent toxin (Pirvp ) that damages the shrimp's hepatopancreas. Like other species of Vibrio, these virulent strains initially colonise the shrimp's stomach, but it is not yet understood how the bacteria or toxins are subsequently able to cross the epithelial barrier and reach the hepatopancreas. Here, by using transcriptomics and system biology methods, we investigate AHPND-induced changes in the stomach of AHPND-causing V. parahaemolyticus (5HP)-infected shrimp and identify host molecular mechanisms that might explain how the integrity of the stomach barrier is compromised. We found that the expression of 376 unique genes was differentially regulated by AHPND infection. Gene ontology, protein interaction, and gene-to-gene correlation expression interaction analyses indicated that in addition to the immune system, a number of these genes were involved in cytoskeleton regulation by Rho GTPase. The involvement of Rho pathway regulation during AHPND pathogenesis was further supported by experiments showing that while Rho inhibitor pretreatment delayed the infection, pretreatment with Rho activator enhanced the pathogenicity of 5HP, and both the bacteria and toxin were detected sooner in the hepatopancreas. Further, disruption of the stomach epithelial structure was found in both Rho preactivated shrimp and in 5HP-infected shrimp. Taken together, we interpret our results to mean that Rho signalling helps to mediate AHPND pathogenesis in shrimp.
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Affiliation(s)
- Tze Hann Ng
- Department of Biotechnology and Bioindustry Sciences, College of Biosciences and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Chia-Wei Lu
- International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan 701, Taiwan
| | - Shih-Shun Lin
- Institute of Biotechnology, National Taiwan University, Taipei, Taiwan
| | - Che-Chih Chang
- Department of Biotechnology and Bioindustry Sciences, College of Biosciences and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Loc H Tran
- Department of Aquaculture Pathology, College of Fisheries, Nong Lam University, Ho Chi Minh City, Vietnam.,ShrimpVet Laboratory, Nong Lam University, Ho Chi Minh City, Vietnam
| | - Wen-Chi Chang
- Institute of Tropical Plant Sciences, College of Biosciences and Biotechnology, National Cheng Kung University, Tainan, Taiwan
| | - Chu-Fang Lo
- Department of Biotechnology and Bioindustry Sciences, College of Biosciences and Biotechnology, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan 701, Taiwan
| | - Han-Ching Wang
- Department of Biotechnology and Bioindustry Sciences, College of Biosciences and Biotechnology, National Cheng Kung University, Tainan, Taiwan.,International Center for the Scientific Development of Shrimp Aquaculture, National Cheng Kung University, Tainan 701, Taiwan
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57
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Castillo D, Pérez-Reytor D, Plaza N, Ramírez-Araya S, Blondel CJ, Corsini G, Bastías R, Loyola DE, Jaña V, Pavez L, García K. Exploring the Genomic Traits of Non-toxigenic Vibrio parahaemolyticus Strains Isolated in Southern Chile. Front Microbiol 2018; 9:161. [PMID: 29472910 PMCID: PMC5809470 DOI: 10.3389/fmicb.2018.00161] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 01/24/2018] [Indexed: 01/30/2023] Open
Abstract
Vibrio parahaemolyticus is the leading cause of seafood-borne gastroenteritis worldwide. As reported in other countries, after the rise and fall of the pandemic strain in Chile, other post-pandemic strains have been associated with clinical cases, including strains lacking the major toxins TDH and TRH. Since the presence or absence of tdh and trh genes has been used for diagnostic purposes and as a proxy of the virulence of V. parahaemolyticus isolates, the understanding of virulence in V. parahaemolyticus strains lacking toxins is essential to detect these strains present in water and marine products to avoid possible food-borne infection. In this study, we characterized the genome of four environmental and two clinical non-toxigenic strains (tdh-, trh-, and T3SS2-). Using whole-genome sequencing, phylogenetic, and comparative genome analysis, we identified the core and pan-genome of V. parahaemolyticus of strains of southern Chile. The phylogenetic tree based on the core genome showed low genetic diversity but the analysis of the pan-genome revealed that all strains harbored genomic islands carrying diverse virulence and fitness factors or prophage-like elements that encode toxins like Zot and RTX. Interestingly, the three strains carrying Zot-like toxin have a different sequence, although the alignment showed some conserved areas with the zot sequence found in V. cholerae. In addition, we identified an unexpected diversity in the genetic architecture of the T3SS1 gene cluster and the presence of the T3SS2 gene cluster in a non-pandemic environmental strain. Our study sheds light on the diversity of V. parahaemolyticus strains from the southern Pacific which increases our current knowledge regarding the global diversity of this organism.
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Affiliation(s)
- Daniel Castillo
- Marine Biological Section, University of Copenhagen, Helsingør, Denmark
| | - Diliana Pérez-Reytor
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Nicolás Plaza
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Sebastián Ramírez-Araya
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile.,Departamento de Ciencias Básicas, Facultad de Ciencias, Universidad Santo Tomás, Santiago, Chile
| | - Carlos J Blondel
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Gino Corsini
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
| | - Roberto Bastías
- Laboratory of Microbiology, Institute of Biology, Pontificia Universidad Católica de Valparaíso, Valparaíso, Chile
| | | | - Víctor Jaña
- Facultad de Medicina Veterinaria y Agronomía, Universidad de Las Américas, Santiago, Chile
| | - Leonardo Pavez
- Facultad de Medicina Veterinaria y Agronomía, Universidad de Las Américas, Santiago, Chile.,Departamento de Ciencias Químicas y Biológicas, Universidad Bernardo O'Higgins, Santiago, Chile
| | - Katherine García
- Instituto de Ciencias Biomédicas, Facultad de Ciencias de la Salud, Universidad Autónoma de Chile, Santiago, Chile
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58
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Zhang Y, Gao H, Osei-Adjei G, Zhang Y, Yang W, Yang H, Yin Z, Huang X, Zhou D. Transcriptional Regulation of the Type VI Secretion System 1 Genes by Quorum Sensing and ToxR in Vibrio parahaemolyticus. Front Microbiol 2017; 8:2005. [PMID: 29085350 PMCID: PMC5650642 DOI: 10.3389/fmicb.2017.02005] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 09/29/2017] [Indexed: 12/26/2022] Open
Abstract
Vibrio parahaemolyticus, the leading cause of seafood-associated gastroenteritis, harbors two separate T6SSs on chromosomes 1 and 2, i.e., T6SS1 (VP1386-1420) and T6SS2 (VPA1025-1046). T6SS1 contains at least 7 putative operons: VP1386-1387, VP1388-1390, VP1392-1391, VP1393-1406, VP1400-1406, VP1409-1407, and VP1410-1420. V. parahaemolyticus AphA and OpaR are the two master regulators of quorum sensing (QS) system that are highly expressed at low cell density and high cell density, respectively. ToxR is a membrane-bound virulence regulatory protein conserved across the Vibrio family. In the present work, we show that ToxR coordinates with AphA and OpaR to repress T6SS1 expression in V. parahaemolyticus. OpaR binds to the promoters of VP1388-1390, VP1400-1406, and VP1409-1407 to repress their transcription, but it appears to negatively regulate VP1393-1406 transcription in an indirect manner. By contrast, AphA negatively regulated the above four T6SS1 operons in an indirect manner. In addition, ToxR binds to the promoters of VP1400-1406 and VP1409-1407 to inhibit their transcription, but it presents an indirect interaction with VP1388-1390 and VP1393-1406 promoters. Notably, the expression of ToxR also manifested in a QS-dependent manner and the highest expression occurred at LCD. Meanwhile, the highest expression of T6SS1 occurred at an OD600 value of 0.6 to 0.8 due to the tight regulation of ToxR and QS, suggesting T6SS1 functions only during the mid-logarithmic growth phase. These observations provide significant insight into the molecular mechanism of T6SS1 gene regulation by QS and ToxR in V. parahaemolyticus.
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Affiliation(s)
- Yiquan Zhang
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - He Gao
- State Key Laboratory for Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Centre for Disease Control and Prevention, Beijing, China
| | | | - Ying Zhang
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Wenhui Yang
- Department of Biosafety, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Huiying Yang
- Department of Biosafety, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Zhe Yin
- Department of Biosafety, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
| | - Xinxiang Huang
- School of Medicine, Jiangsu University, Zhenjiang, China
| | - Dongsheng Zhou
- Department of Biosafety, State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing, China
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