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Fabian B, Foster C, Asher A, Hassan K, Paulsen I, Tetu S. Identifying the suite of genes central to swimming in the biocontrol bacterium Pseudomonas protegens Pf-5. Microb Genom 2024; 10:001212. [PMID: 38546328 PMCID: PMC11004494 DOI: 10.1099/mgen.0.001212] [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: 01/01/2024] [Accepted: 02/20/2024] [Indexed: 04/12/2024] Open
Abstract
Swimming motility is a key bacterial trait, important to success in many niches. Biocontrol bacteria, such as Pseudomonas protegens Pf-5, are increasingly used in agriculture to control crop diseases, where motility is important for colonization of the plant rhizosphere. Swimming motility typically involves a suite of flagella and chemotaxis genes, but the specific gene set employed for both regulation and biogenesis can differ substantially between organisms. Here we used transposon-directed insertion site sequencing (TraDIS), a genome-wide approach, to identify 249 genes involved in P. protegens Pf-5 swimming motility. In addition to the expected flagella and chemotaxis, we also identified a suite of additional genes important for swimming, including genes related to peptidoglycan turnover, O-antigen biosynthesis, cell division, signal transduction, c-di-GMP turnover and phosphate transport, and 27 conserved hypothetical proteins. Gene knockout mutants and TraDIS data suggest that defects in the Pst phosphate transport system lead to enhanced swimming motility. Overall, this study expands our knowledge of pseudomonad motility and highlights the utility of a TraDIS-based approach for analysing the functions of thousands of genes. This work sets a foundation for understanding how swimming motility may be related to the inconsistency in biocontrol bacteria performance in the field.
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Affiliation(s)
- B.K. Fabian
- School of Natural Sciences, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
| | - C. Foster
- School of Natural Sciences, Macquarie University, Sydney, Australia
| | - A. Asher
- School of Natural Sciences, Macquarie University, Sydney, Australia
| | - K.A. Hassan
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
- School of Environmental and Life Sciences, University of Newcastle, Newcastle, Australia
| | - I.T. Paulsen
- School of Natural Sciences, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
| | - S.G. Tetu
- School of Natural Sciences, Macquarie University, Sydney, Australia
- ARC Centre of Excellence in Synthetic Biology, Macquarie University, Sydney, Australia
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2
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Verbeelen T, Fernandez CA, Nguyen TH, Gupta S, Aarts R, Tabury K, Leroy B, Wattiez R, Vlaeminck SE, Leys N, Ganigué R, Mastroleo F. Whole transcriptome analysis highlights nutrient limitation of nitrogen cycle bacteria in simulated microgravity. NPJ Microgravity 2024; 10:3. [PMID: 38200027 PMCID: PMC10781756 DOI: 10.1038/s41526-024-00345-z] [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: 09/20/2023] [Accepted: 01/01/2024] [Indexed: 01/12/2024] Open
Abstract
Regenerative life support systems (RLSS) will play a vital role in achieving self-sufficiency during long-distance space travel. Urine conversion into a liquid nitrate-based fertilizer is a key process in most RLSS. This study describes the effects of simulated microgravity (SMG) on Comamonas testosteroni, Nitrosomonas europaea, Nitrobacter winogradskyi and a tripartite culture of the three, in the context of nitrogen recovery for the Micro-Ecological Life Support System Alternative (MELiSSA). Rotary cell culture systems (RCCS) and random positioning machines (RPM) were used as SMG analogues. The transcriptional responses of the cultures were elucidated. For CO2-producing C. testosteroni and the tripartite culture, a PermaLifeTM PL-70 cell culture bag mounted on an in-house 3D-printed holder was applied to eliminate air bubble formation during SMG cultivation. Gene expression changes indicated that the fluid dynamics in SMG caused nutrient and O2 limitation. Genes involved in urea hydrolysis and nitrification were minimally affected, while denitrification-related gene expression was increased. The findings highlight potential challenges for nitrogen recovery in space.
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Affiliation(s)
- Tom Verbeelen
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Celia Alvarez Fernandez
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium
| | - Thanh Huy Nguyen
- Department of Proteomics and Microbiology, University of Mons, Av. Du Champs de Mars 6, 7000, Mons, Belgium
| | - Surya Gupta
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium
| | - Raf Aarts
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium
| | - Kevin Tabury
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium
| | - Baptiste Leroy
- Department of Proteomics and Microbiology, University of Mons, Av. Du Champs de Mars 6, 7000, Mons, Belgium
| | - Ruddy Wattiez
- Department of Proteomics and Microbiology, University of Mons, Av. Du Champs de Mars 6, 7000, Mons, Belgium
| | - Siegfried E Vlaeminck
- Research Group of Sustainable Energy, Air and Water Technology, Department of Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, 2020, Antwerp, Belgium
- Centre for Advanced Process Technology for Urban REsource Recovery (CAPTURE), Frieda Saeysstraat 1, 9052, Ghent, Belgium
| | - Natalie Leys
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium
| | - Ramon Ganigué
- Center for Microbial Ecology and Technology (CMET), Ghent University, Coupure Links 653, 9000, Ghent, Belgium
- Centre for Advanced Process Technology for Urban REsource Recovery (CAPTURE), Frieda Saeysstraat 1, 9052, Ghent, Belgium
| | - Felice Mastroleo
- Nuclear Medical Applications, Belgian Nuclear Research Centre (SCK CEN), Boeretang 200, 2400, Mol, Belgium.
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3
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Nie H, Nie L, Xiao Y, Song M, Zhou T, He J, Chen W, Huang Q. The phosphodiesterase DibA interacts with the c-di-GMP receptor LapD and specifically regulates biofilm in Pseudomonas putida. Mol Microbiol 2024; 121:1-17. [PMID: 37927230 DOI: 10.1111/mmi.15189] [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: 07/03/2023] [Revised: 09/30/2023] [Accepted: 10/17/2023] [Indexed: 11/07/2023]
Abstract
The ubiquitous bacterial second messenger c-di-GMP is synthesized by diguanylate cyclase and degraded by c-di-GMP-specific phosphodiesterase. The genome of Pseudomonas putida contains dozens of genes encoding diguanylate cyclase/phosphodiesterase, but the phenotypical-genotypical correlation and functional mechanism of these genes are largely unknown. Herein, we characterize the function and mechanism of a P. putida phosphodiesterase named DibA. DibA consists of a PAS domain, a GGDEF domain, and an EAL domain. The EAL domain is active and confers DibA phosphodiesterase activity. The GGDEF domain is inactive, but it promotes the phosphodiesterase activity of the EAL domain via binding GTP. Regarding phenotypic regulation, DibA modulates the cell surface adhesin LapA level in a c-di-GMP receptor LapD-dependent manner, thereby inhibiting biofilm formation. Moreover, DibA interacts and colocalizes with LapD in the cell membrane, and the interaction between DibA and LapD promotes the PDE activity of DibA. Besides, except for interacting with DibA and LapD itself, LapD is found to interact with 11 different potential diguanylate cyclases/phosphodiesterases in P. putida, including the conserved phosphodiesterase BifA. Overall, our findings demonstrate the functional mechanism by which DibA regulates biofilm formation and expand the understanding of the LapD-mediated c-di-GMP signaling network in P. putida.
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Affiliation(s)
- Hailing Nie
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Liang Nie
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Yujie Xiao
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Miaomiao Song
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Tiantian Zhou
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Jinzhi He
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Wenli Chen
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Qiaoyun Huang
- National Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
- Hubei Key Laboratory of Soil Environment and Pollution Remediation, College of Resources and Environment, Huazhong Agricultural University, Wuhan, China
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4
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Xu M, Lyu Y, Cheng K, Zhang B, Cai Z, Chen G, Zhou J. Interactions between quorum sensing/quorum quenching and virulence genes may affect coral health by regulating symbiotic bacterial community. ENVIRONMENTAL RESEARCH 2023; 238:117221. [PMID: 37775014 DOI: 10.1016/j.envres.2023.117221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 09/11/2023] [Accepted: 09/21/2023] [Indexed: 10/01/2023]
Abstract
Quorum sensing (QS) and quorum quenching (QQ) are two antagonistic processes that may regulate the composition, function and structure of bacterial community. In coral holobiont, autoinducers signaling mediate the communication pathways between interspecies and intraspecies bacteria, which regulate the expression of the virulence factors that can damage host health. However, under environmental stressors, the interaction between the QS/QQ gene and virulence factors and their role in the bacterial communities and coral bleaching is still not fully clear. To address this question, here, metagenomics method was used to examine the profile of QS/QQ and virulence genes from a deeply sequenced microbial database, obtained from three bleached and non-bleached corals species. The prediction of bacterial genes of bleached samples involved in functional metabolic pathways were remarkably decreased, and the bacterial community structure on bleached samples was significantly different compared to non-bleached samples. The distribution and significant difference in QS/QQ and virulence genes were also carried out. We found that Proteobacteria was dominant bacteria among all samples, and AI-1 system is widespread within this group of bacteria. The identified specific genes consistently exhibited a trend of increased pathogenicity in bleached corals relative to non-bleached corals. The abundance of pathogenicity-associated QS genes, including bapA, pfoA and dgcB genes, were significantly increased in bleached corals and can encode the protein of biofilm formation and the membrane damaging toxins promoting pathogenic adhesion and infection. Similarly, the virulence genes, such as superoxide dismutase (Mn-SOD gene), metalloproteinase (yme1, yydH and zmpB), glycosidases (malE, malF, malG, and malK) and LodAB (lodB) genes significantly increased. Conversely, QQ genes that inhibit QS activity and virulence factors to defense the pathogens, including blpA, lsrK, amiE, aprE and gmuG showed a significant decrease in bleached groups. Furthermore, the significant correlations were found among virulence, QS/QQ genes, and coral associated bacterial community, and the virulence genes interact with key QS/QQ genes, directly or indirectly influence symbiotic bacterial communities homeostasis, thereby impacting coral health. It suggested that the functional and structural divergence in the symbiont bacteria may be partially attribute to the interplay, involving interactions among the host, bacterial communication signal systems, and bacterial virulence factors. In conclusion, these data helped to reveal the characteristic behavior of coral symbiotic bacteria, and facilitated a better understanding of bleaching mechanism from a chemical ecological perspective.
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Affiliation(s)
- Meiting Xu
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai, 264209, Shandong Province, PR China
| | - Yihua Lyu
- Nansha Islands Coral Reef Ecosystem National Observation and Research Station, Guangzhou, 510300, PR China
| | - Keke Cheng
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China
| | - Boya Zhang
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China
| | - Zhonghua Cai
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China
| | - Guofu Chen
- School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China; School of Marine Science and Technology, Harbin Institute of Technology (Weihai), Weihai, 264209, Shandong Province, PR China.
| | - Jin Zhou
- Shenzhen Public Platform for Screening and Application of Marine Microbial Resources, Institute for Ocean Engineering, Shenzhen International Graduate School, Tsinghua University, Shenzhen, 518055, PR China.
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Blanco-Romero E, Durán D, Garrido-Sanz D, Redondo-Nieto M, Martín M, Rivilla R. Adaption of Pseudomonas ogarae F113 to the Rhizosphere Environment-The AmrZ-FleQ Hub. Microorganisms 2023; 11:microorganisms11041037. [PMID: 37110460 PMCID: PMC10146422 DOI: 10.3390/microorganisms11041037] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/10/2023] [Accepted: 04/13/2023] [Indexed: 04/29/2023] Open
Abstract
Motility and biofilm formation are two crucial traits in the process of rhizosphere colonization by pseudomonads. The regulation of both traits requires a complex signaling network that is coordinated by the AmrZ-FleQ hub. In this review, we describe the role of this hub in the adaption to the rhizosphere. The study of the direct regulon of AmrZ and the phenotypic analyses of an amrZ mutant in Pseudomonas ogarae F113 has shown that this protein plays a crucial role in the regulation of several cellular functions, including motility, biofilm formation, iron homeostasis, and bis-(3'-5')-cyclic dimeric guanosine monophosphate (c-di-GMP) turnover, controlling the synthesis of extracellular matrix components. On the other hand, FleQ is the master regulator of flagellar synthesis in P. ogarae F113 and other pseudomonads, but its implication in the regulation of multiple traits related with environmental adaption has been shown. Genomic scale studies (ChIP-Seq and RNA-Seq) have shown that in P. ogarae F113, AmrZ and FleQ are general transcription factors that regulate multiple traits. It has also been shown that there is a common regulon shared by the two transcription factors. Moreover, these studies have shown that AmrZ and FleQ form a regulatory hub that inversely regulate traits such as motility, extracellular matrix component production, and iron homeostasis. The messenger molecule c-di-GMP plays an essential role in this hub since its production is regulated by AmrZ and it is sensed by FleQ and required for its regulatory role. This regulatory hub is functional both in culture and in the rhizosphere, indicating that the AmrZ-FleQ hub is a main player of P. ogarae F113 adaption to the rhizosphere environment.
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Affiliation(s)
- Esther Blanco-Romero
- Departamento de Biología, Facultad de Ciencias, Universidad Autónoma de Madrid, Darwin 2, 28049 Madrid, Spain
| | - David Durán
- 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
- 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
| | - Marta Martín
- 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
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6
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Patel JS, Selvaraj V, More P, Bahmani R, Borza T, Prithiviraj B. A Plant Biostimulant from Ascophyllum nodosum Potentiates Plant Growth Promotion and Stress Protection Activity of Pseudomonas protegens CHA0. PLANTS (BASEL, SWITZERLAND) 2023; 12:1208. [PMID: 36986897 PMCID: PMC10053968 DOI: 10.3390/plants12061208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/28/2023] [Accepted: 03/06/2023] [Indexed: 06/18/2023]
Abstract
Abiotic stresses, including salinity stress, affect numerous crops, causing yield reduction, and, as a result, important economic losses. Extracts from the brown alga Ascophyllum nodosum (ANE), and compounds secreted by the Pseudomonas protegens strain, CHA0, can mitigate these effects by inducing tolerance against salt stress. However, the influence of ANE on P. protegens CHA0 secretion, and the combined effects of these two biostimulants on plant growth, are not known. Fucoidan, alginate, and mannitol are abundant components of brown algae and of ANE. Reported here are the effects of a commercial formulation of ANE, fucoidan, alginate, and mannitol, on pea (Pisum sativum), and on the plant growth-promoting activity of P. protegens CHA0. In most situations, ANE and fucoidan increased indole-3-acetic acid (IAA) and siderophore production, phosphate solubilization, and hydrogen cyanide (HCN) production by P. protegens CHA0. Colonization of pea roots by P. protegens CHA0 was found to be increased mostly by ANE and fucoidan in normal conditions and under salt stress. Applications of P. protegens CHA0 combined with ANE, or with fucoidan, alginate, and mannitol, generally augmented root and shoot growth in normal and salinity stress conditions. Real-time quantitative PCR analyses of P. protegens revealed that, in many instances, ANE and fucoidan enhanced the expression of several genes involved in chemotaxis (cheW and WspR), pyoverdine production (pvdS), and HCN production (hcnA), but gene expression patterns overlapped only occasionally those of growth-promoting parameters. Overall, the increased colonization and the enhanced activities of P. protegens CHA0 in the presence of ANE and its components mitigated salinity stress in pea. Among treatments, ANE and fucoidan were found responsible for most of the increased activities of P. protegens CHA0 and the improved plant growth.
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7
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Wang X, Wu H, Wang L, Wang Y, Wang X, Wang H, Lu Z. Global transcriptional and translational regulation of Sphingomonas melonis TY in response to hyperosmotic stress. ENVIRONMENTAL RESEARCH 2023; 219:115014. [PMID: 36549482 DOI: 10.1016/j.envres.2022.115014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 11/10/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
Hyperosmotic stress is one of the most ubiquitous stress factors in microbial habitats and impairs the efficiency of bacteria performing vital biochemical tasks. Sphingomonas serves as a 'superstar' of plant defense and pollutant degradation, and is widely existed in the environment. However, it is still unclear that how Sphingomonas sp. survives under hyperosmotic stress conditions. In this study, multiomics profiling analysis was conducted with S. melonis TY under hyperosmotic conditions to investigate the intracellular hyperosmotic responses. The transcriptome and proteome revealed that sensing systems, including most membrane protein coding genes were upregulated, genes related to two-component systems were tiered adjusted to reset the whole system, other stress response regulators such as sigma-70 were also significantly tiered upregulated. In addition, transport systems together with compatible solute biosynthesis related genes were significantly upregulated to accumulate intracellular nutrients and compatible solutes. When treated with hyperosmotic stress, redox-stress response systems were triggered and mechanosensitive channels together with ion transporters were induced to maintain cellular ion homeostasis. In addition, cellular concentration of c-di-guanosine monophosphate synthetase (c-di-GMP) was reduced, followed by negative influences on genes involved in flagellar assembly and chemotaxis pathways, leading to severe damage to the athletic ability of S. melonis TY, and causing detachments of biofilms. Briefly, this research revealed a comprehensive response mechanism of S. melonis TY exposure to hyperosmotic stress, and emphasized that flagellar assembly and biofilm formation were vulnerable to hyperosmotic conditions. Importance. Sphingomonas, a genus with versatile functions survives extensively, lauded for its prominent role in plant protection and environmental remediation. Current evidence shows that hyperosmotic stress as a ubiquitous environmental factor, usually threatens the survival of microbes and thus impairs the efficiency of their environmental functions. Thus, it is essential to explore the cellular responses to hyperosmotic stress. Hence, this research will greatly enhance our understanding of the global transcriptional and translational regulation of S. melonis TY in response to hyperosmotic stress, leading to broader perspectives on the impacts of stressful environments.
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Affiliation(s)
- Xiaoyu Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China; Cancer Center, Zhejiang University, Hangzhou, 310058, China
| | - Hao Wu
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China; Cancer Center, Zhejiang University, Hangzhou, 310058, China
| | - Lvjing Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China; Cancer Center, Zhejiang University, Hangzhou, 310058, China
| | - Yihan Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China; Cancer Center, Zhejiang University, Hangzhou, 310058, China
| | - Xuejun Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China; Cancer Center, Zhejiang University, Hangzhou, 310058, China
| | - Haixia Wang
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
| | - Zhenmei Lu
- MOE Laboratory of Biosystem Homeostasis and Protection, College of Life Sciences, Zhejiang University, Hangzhou, 310058, China; Cancer Center, Zhejiang University, Hangzhou, 310058, China.
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8
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Yan H, Chen W. The Promise and Challenges of Cyclic Dinucleotides as Molecular Adjuvants for Vaccine Development. Vaccines (Basel) 2021; 9:917. [PMID: 34452042 PMCID: PMC8402453 DOI: 10.3390/vaccines9080917] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 08/05/2021] [Accepted: 08/10/2021] [Indexed: 12/14/2022] Open
Abstract
Cyclic dinucleotides (CDNs), originally discovered as bacterial second messengers, play critical roles in bacterial signal transduction, cellular processes, biofilm formation, and virulence. The finding that CDNs can trigger the innate immune response in eukaryotic cells through the stimulator of interferon genes (STING) signalling pathway has prompted the extensive research and development of CDNs as potential immunostimulators and novel molecular adjuvants for induction of systemic and mucosal innate and adaptive immune responses. In this review, we summarize the chemical structure, biosynthesis regulation, and the role of CDNs in enhancing the crosstalk between host innate and adaptive immune responses. We also discuss the strategies to improve the efficient delivery of CDNs and the recent advance and future challenges in the development of CDNs as potential adjuvants in prophylactic vaccines against infectious diseases and in therapeutic vaccines against cancers.
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Affiliation(s)
- Hongbin Yan
- Department of Chemistry, Brock University, St. Catharines, ON L2S 3A1, Canada
| | - Wangxue Chen
- Human Health and Therapeutics Research Centre, National Research Council Canada, Ottawa, ON K1A 0R6, Canada
- Department of Biological Sciences, Brock University, St. Catharines, ON L2S 3A1, Canada
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9
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Pecina A, Schwan M, Blagotinsek V, Rick T, Klüber P, Leonhard T, Bange G, Thormann KM. The Stand-Alone PilZ-Domain Protein MotL Specifically Regulates the Activity of the Secondary Lateral Flagellar System in Shewanella putrefaciens. Front Microbiol 2021; 12:668892. [PMID: 34140945 PMCID: PMC8203827 DOI: 10.3389/fmicb.2021.668892] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/19/2021] [Indexed: 11/13/2022] Open
Abstract
A number of bacterial species control the function of the flagellar motor in response to the levels of the secondary messenger c-di-GMP, which is often mediated by c-di-GMP-binding proteins that act as molecular brakes or clutches to slow the motor rotation. The gammaproteobacterium Shewanella putrefaciens possesses two distinct flagellar systems, the primary single polar flagellum and a secondary system with one to five lateral flagellar filaments. Here, we identified a protein, MotL, which specifically regulates the activity of the lateral, but not the polar, flagellar motors in response to the c-di-GMP levels. MotL only consists of a single PilZ domain binding c-di-GMP, which is crucial for its function. Deletion and overproduction analyses revealed that MotL slows down the lateral flagella at elevated levels of c-di-GMP, and may speed up the lateral flagellar-mediated movement at low c-di-GMP concentrations. In vitro interaction studies hint at an interaction of MotL with the C-ring of the lateral flagellar motors. This study shows a differential c-di-GMP-dependent regulation of the two flagellar systems in a single species, and implicates that PilZ domain-only proteins can also act as molecular regulators to control the flagella-mediated motility in bacteria.
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Affiliation(s)
- Anna Pecina
- Department of Microbiology and Molecular Biology, Justus-Liebig-Universität Gießen, Giessen, Germany
| | - Meike Schwan
- Department of Microbiology and Molecular Biology, Justus-Liebig-Universität Gießen, Giessen, Germany
| | - Vitan Blagotinsek
- Department of Chemistry, SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
| | - Tim Rick
- Department of Microbiology and Molecular Biology, Justus-Liebig-Universität Gießen, Giessen, Germany
| | - Patrick Klüber
- Department of Microbiology and Molecular Biology, Justus-Liebig-Universität Gießen, Giessen, Germany
| | - Tabea Leonhard
- Department of Microbiology and Molecular Biology, Justus-Liebig-Universität Gießen, Giessen, Germany
| | - Gert Bange
- Department of Chemistry, SYNMIKRO Research Center, Philipps-University Marburg, Marburg, Germany
| | - Kai M Thormann
- Department of Microbiology and Molecular Biology, Justus-Liebig-Universität Gießen, Giessen, Germany
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10
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De Smet J, Wagemans J, Hendrix H, Staes I, Visnapuu A, Horemans B, Aertsen A, Lavigne R. Bacteriophage-mediated interference of the c-di-GMP signalling pathway in Pseudomonas aeruginosa. Microb Biotechnol 2021; 14:967-978. [PMID: 33314648 PMCID: PMC8085984 DOI: 10.1111/1751-7915.13728] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Revised: 10/19/2020] [Accepted: 11/22/2020] [Indexed: 01/10/2023] Open
Abstract
C-di-GMP is a key signalling molecule which impacts bacterial motility and biofilm formation and is formed by the condensation of two GTP molecules by a diguanylate cyclase. We here describe the identification and characterization of a family of bacteriophage-encoded peptides that directly impact c-di-GMP signalling in Pseudomonas aeruginosa. These phage proteins target Pseudomonas diguanylate cyclase YfiN by direct protein interaction (termed YIPs, YfiN Interacting Peptides). YIPs induce an increase of c-di-GMP production in the host cell, resulting in a decrease in motility and an increase in biofilm mass in P. aeruginosa. A dynamic analysis of the biofilm morphology indicates a denser biofilm structure after induction of the phage protein. This intracellular signalling interference strategy by a lytic phage constitutes an unexplored phage-based mechanism of metabolic regulation and could potentially serve as inspiration for the development of molecules that interfere with biofilm formation in P. aeruginosa and other pathogens.
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Affiliation(s)
- Jeroen De Smet
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenHeverlee3001Belgium
- Present address:
Lab4FoodDepartment of Microbial and Molecular Systems (M2S)KU Leuven Campus GeelGeel2440Belgium
| | - Jeroen Wagemans
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenHeverlee3001Belgium
| | - Hanne Hendrix
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenHeverlee3001Belgium
| | - Ines Staes
- Laboratory of Food MicrobiologyDepartment of Microbial and Molecular SystemsKU LeuvenHeverlee3001Belgium
| | - Annegrete Visnapuu
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenHeverlee3001Belgium
| | - Benjamin Horemans
- Department of Earth and Environmental SciencesKU LeuvenHeverlee3001Belgium
| | - Abram Aertsen
- Laboratory of Food MicrobiologyDepartment of Microbial and Molecular SystemsKU LeuvenHeverlee3001Belgium
| | - Rob Lavigne
- Laboratory of Gene TechnologyDepartment of BiosystemsKU LeuvenHeverlee3001Belgium
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11
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Bouteiller M, Dupont C, Bourigault Y, Latour X, Barbey C, Konto-Ghiorghi Y, Merieau A. Pseudomonas Flagella: Generalities and Specificities. Int J Mol Sci 2021; 22:ijms22073337. [PMID: 33805191 PMCID: PMC8036289 DOI: 10.3390/ijms22073337] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 03/22/2021] [Accepted: 03/22/2021] [Indexed: 12/21/2022] Open
Abstract
Flagella-driven motility is an important trait for bacterial colonization and virulence. Flagella rotate and propel bacteria in liquid or semi-liquid media to ensure such bacterial fitness. Bacterial flagella are composed of three parts: a membrane complex, a flexible-hook, and a flagellin filament. The most widely studied models in terms of the flagellar apparatus are E. coli and Salmonella. However, there are many differences between these enteric bacteria and the bacteria of the Pseudomonas genus. Enteric bacteria possess peritrichous flagella, in contrast to Pseudomonads, which possess polar flagella. In addition, flagellar gene expression in Pseudomonas is under a four-tiered regulatory circuit, whereas enteric bacteria express flagellar genes in a three-step manner. Here, we use knowledge of E. coli and Salmonella flagella to describe the general properties of flagella and then focus on the specificities of Pseudomonas flagella. After a description of flagellar structure, which is highly conserved among Gram-negative bacteria, we focus on the steps of flagellar assembly that differ between enteric and polar-flagellated bacteria. In addition, we summarize generalities concerning the fuel used for the production and rotation of the flagellar macromolecular complex. The last part summarizes known regulatory pathways and potential links with the type-six secretion system (T6SS).
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Affiliation(s)
- Mathilde Bouteiller
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (C.D.); (Y.B.); (X.L.); (C.B.); (Y.K.-G.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, 76821 Mont-Saint-Aignan, France
| | - Charly Dupont
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (C.D.); (Y.B.); (X.L.); (C.B.); (Y.K.-G.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, 76821 Mont-Saint-Aignan, France
| | - Yvann Bourigault
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (C.D.); (Y.B.); (X.L.); (C.B.); (Y.K.-G.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, 76821 Mont-Saint-Aignan, France
| | - Xavier Latour
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (C.D.); (Y.B.); (X.L.); (C.B.); (Y.K.-G.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, 76821 Mont-Saint-Aignan, France
| | - Corinne Barbey
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (C.D.); (Y.B.); (X.L.); (C.B.); (Y.K.-G.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, 76821 Mont-Saint-Aignan, France
| | - Yoan Konto-Ghiorghi
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (C.D.); (Y.B.); (X.L.); (C.B.); (Y.K.-G.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, 76821 Mont-Saint-Aignan, France
| | - Annabelle Merieau
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (C.D.); (Y.B.); (X.L.); (C.B.); (Y.K.-G.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, 76821 Mont-Saint-Aignan, France
- Correspondence:
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12
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Collins AJ, Smith TJ, Sondermann H, O'Toole GA. From Input to Output: The Lap/c-di-GMP Biofilm Regulatory Circuit. Annu Rev Microbiol 2020; 74:607-631. [PMID: 32689917 DOI: 10.1146/annurev-micro-011520-094214] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Biofilms are the dominant bacterial lifestyle. The regulation of the formation and dispersal of bacterial biofilms has been the subject of study in many organisms. Over the last two decades, the mechanisms of Pseudomonas fluorescens biofilm formation and regulation have emerged as among the best understood of any bacterial biofilm system. Biofilm formation by P. fluorescens occurs through the localization of an adhesin, LapA, to the outer membrane via a variant of the classical type I secretion system. The decision between biofilm formation and dispersal is mediated by LapD, a c-di-GMP receptor, and LapG, a periplasmic protease, which together control whether LapA is retained or released from the cell surface. LapA localization is also controlled by a complex network of c-di-GMP-metabolizing enzymes. This review describes the current understanding of LapA-mediated biofilm formation by P. fluorescens and discusses several emerging models for the regulation and function of this adhesin.
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Affiliation(s)
- Alan J Collins
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.,Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA;
| | - T Jarrod Smith
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA; .,Institute of Molecular Biology, University of Oregon, Eugene, Oregon 97403, USA
| | | | - George A O'Toole
- Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755, USA;
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13
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Hueso-Gil Á, Calles B, de Lorenzo V. The Wsp intermembrane complex mediates metabolic control of the swim-attach decision of Pseudomonas putida. Environ Microbiol 2020; 22:3535-3547. [PMID: 32519402 DOI: 10.1111/1462-2920.15126] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 06/07/2020] [Accepted: 06/08/2020] [Indexed: 11/29/2022]
Abstract
Pseudomonas putida is a microorganism of biotechnological interest that-similar to many other environmental bacteria-adheres to surfaces and forms biofilms. Although various mechanisms contributing to the swim-attach decision have been studied in this species, the role of a 7-gene operon homologous to the wsp cluster of Pseudomonas aeruginosa-which regulates cyclic di-GMP (cdGMP) levels upon surface contact-remained to be investigated. In this work, the function of the wsp operon of P. putida KT2440 has been characterized through inspection of single and multiple wsp deletion variants, complementation with Pseudomonas aeruginosa's homologues, combined with mutations of regulatory genes fleQ and fleN and removal of the flagellar regulator fglZ. The ability of the resulting strains to form biofilms at 6 and 24 h under three different carbon regimes (citrate, glucose and fructose) revealed that the Wsp complex delivers a similar function to both Pseudomonas species. In P. putida, the key components include WspR, a protein that harbours the domain for producing cdGMP, and WspF, which controls its activity. These results not only contribute to a deeper understanding of the network that regulates the sessile-planktonic decision of P. putida but also suggest strategies to exogenously control such a lifestyle switch.
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Affiliation(s)
- Ángeles Hueso-Gil
- Systems Biology Department, Centro Nacional de Biotecnología-CSIC, Campus de Cantoblanco, Madrid, 28049, Spain
| | - Belén Calles
- Systems Biology Department, Centro Nacional de Biotecnología-CSIC, Campus de Cantoblanco, Madrid, 28049, Spain
| | - Víctor de Lorenzo
- Systems Biology Department, Centro Nacional de Biotecnología-CSIC, Campus de Cantoblanco, Madrid, 28049, Spain
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14
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Grenga L, Little RH, Chandra G, Woodcock SD, Saalbach G, Morris RJ, Malone JG. Control of mRNA translation by dynamic ribosome modification. PLoS Genet 2020; 16:e1008837. [PMID: 32584816 PMCID: PMC7343187 DOI: 10.1371/journal.pgen.1008837] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/08/2020] [Accepted: 05/07/2020] [Indexed: 01/28/2023] Open
Abstract
Control of mRNA translation is a crucial regulatory mechanism used by bacteria to respond to their environment. In the soil bacterium Pseudomonas fluorescens, RimK modifies the C-terminus of ribosomal protein RpsF to influence important aspects of rhizosphere colonisation through proteome remodelling. In this study, we show that RimK activity is itself under complex, multifactorial control by the co-transcribed phosphodiesterase trigger enzyme (RimA) and a polyglutamate-specific protease (RimB). Furthermore, biochemical experimentation and mathematical modelling reveal a role for the nucleotide second messenger cyclic-di-GMP in coordinating these activities. Active ribosome regulation by RimK occurs by two main routes: indirectly, through changes in the abundance of the global translational regulator Hfq and directly, with translation of surface attachment factors, amino acid transporters and key secreted molecules linked specifically to RpsF modification. Our findings show that post-translational ribosomal modification functions as a rapid-response mechanism that tunes global gene translation in response to environmental signals.
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Affiliation(s)
- Lucia Grenga
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom
| | | | - Govind Chandra
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
| | | | - Gerhard Saalbach
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
| | - Richard James Morris
- Computational and Systems Biology, John Innes Centre, Norwich, Norfolk, United Kingdom
| | - Jacob George Malone
- Molecular Microbiology, John Innes Centre, Norwich, Norfolk, United Kingdom
- School of Biological Sciences, University of East Anglia, Norwich, Norfolk, United Kingdom
- * E-mail:
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15
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Ma GL, Chandra H, Liang ZX. Taming the flagellar motor of pseudomonads with a nucleotide messenger. Environ Microbiol 2020; 22:2496-2513. [PMID: 32329141 DOI: 10.1111/1462-2920.15036] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/20/2020] [Accepted: 04/21/2020] [Indexed: 01/11/2023]
Abstract
Pseudomonads rely on the flagellar motor to rotate a polar flagellum for swimming and swarming, and to sense surfaces for initiating the motile-to-sessile transition to adopt a surface-dwelling lifestyle. Deciphering the function and regulation of the flagellar motor is of paramount importance for understanding the behaviours of environmental and pathogenic pseudomonads. Recent studies disclosed the preeminent role played by the messenger c-di-GMP in controlling the real-time performance of the flagellar motor in pseudomonads. The studies revealed that c-di-GMP controls the dynamic exchange of flagellar stator units to regulate motor torque/speed and modulates the frequency of flagellar motor switching via the chemosensory signalling pathways. Apart from being a rotary motor, the flagellar motor is emerging as a mechanosensor that transduces surface-induced mechanical signals into an increase of cellular c-di-GMP concentration to initiate the cellular programs required for long-term colonization. Collectively, the studies generate long-awaited mechanistic insights into how c-di-GMP regulates bacterial motility and the motile-to-sessile transition. The new findings also raise the fundamental questions of how cellular c-di-GMP concentrations are dynamically coupled to flagellar output and the proton-motive force, and how c-di-GMP signalling is coordinated spatiotemporally to fine-tune flagellar response and the behaviour of pseudomonads in solutions and on surfaces.
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Affiliation(s)
- Guang-Lei Ma
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
| | - Hartono Chandra
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
| | - Zhao-Xun Liang
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore.,Singapore Centre for Environmental Life Sciences Engineering (SCELSE), Nanyang Technological University, 60 Nanyang Drive, S637551, Singapore
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16
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Bouteiller M, Gallique M, Bourigault Y, Kosta A, Hardouin J, Massier S, Konto-Ghiorghi Y, Barbey C, Latour X, Chane A, Feuilloley M, Merieau A. Crosstalk between the Type VI Secretion System and the Expression of Class IV Flagellar Genes in the Pseudomonas fluorescens MFE01 Strain. Microorganisms 2020; 8:microorganisms8050622. [PMID: 32344878 PMCID: PMC7286023 DOI: 10.3390/microorganisms8050622] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Revised: 04/16/2020] [Accepted: 04/23/2020] [Indexed: 11/16/2022] Open
Abstract
Type VI secretion systems (T6SSs) are contractile bacterial multiprotein nanomachines that enable the injection of toxic effectors into prey cells. The Pseudomonas fluorescens MFE01 strain has T6SS antibacterial activity and can immobilise competitive bacteria through the T6SS. Hcp1 (hemolysin co-regulated protein 1), a constituent of the T6SS inner tube, is involved in such prey cell inhibition of motility. Paradoxically, disruption of the hcp1 or T6SS contractile tail tssC genes results in the loss of the mucoid and motile phenotypes in MFE01. Here, we focused on the relationship between T6SS and flagella-associated motility. Electron microscopy revealed the absence of flagellar filaments for MFE01Δhcp1 and MFE01ΔtssC mutants. Transcriptomic analysis showed a reduction in the transcription of class IV flagellar genes in these T6SS mutants. However, transcription of fliA, the gene encoding the class IV flagellar sigma factor, was unaffected. Over-expression of fliA restored the motile and mucoid phenotypes in both MFE01Δhcp1+fliA, and MFE01ΔtssC+fliA and a fliA mutant displayed the same phenotypes as MFE01Δhcp1 and MFE01ΔtssC. Moreover, the FliA anti-sigma factor FlgM was not secreted in the T6SS mutants, and flgM over-expression reduced both motility and mucoidy. This study provides arguments to unravel the crosstalk between T6SS and motility.
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Affiliation(s)
- Mathilde Bouteiller
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (M.G.); (Y.B.); (Y.K.-G.); (C.B.); (X.L.); (A.C.); (M.F.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, F-76821 Mont-Saint-Aignan, France
| | - Mathias Gallique
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (M.G.); (Y.B.); (Y.K.-G.); (C.B.); (X.L.); (A.C.); (M.F.)
- Meakins-Christie laboratories, Research Institute of the McGill University Health Centre, Montreal, QC H4A 3J1, Canada
- Department of Chemical Engineering, McGill University, Montreal, QC H3A 0C5, Canada
| | - Yvann Bourigault
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (M.G.); (Y.B.); (Y.K.-G.); (C.B.); (X.L.); (A.C.); (M.F.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, F-76821 Mont-Saint-Aignan, France
| | - Artemis Kosta
- Plateforme de Microscopie de l’Institut de Microbiologie de la Méditerranée, IMM, Institut de Microbiologie, FR3479, Campus CNRS, 13402 Marseille cedex 20, France;
| | - Julie Hardouin
- Polymers, Biopolymers, Surface Laboratory, UMR 6270 CNRS, University of Rouen, F-76821 Mont-Saint-Aignan cedex, France; (J.H.); (S.M.)
- PISSARO Proteomics Facility, Université de Rouen, F-76821 Mont-Saint-Aignan, France
| | - Sebastien Massier
- Polymers, Biopolymers, Surface Laboratory, UMR 6270 CNRS, University of Rouen, F-76821 Mont-Saint-Aignan cedex, France; (J.H.); (S.M.)
- PISSARO Proteomics Facility, Université de Rouen, F-76821 Mont-Saint-Aignan, France
| | - Yoan Konto-Ghiorghi
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (M.G.); (Y.B.); (Y.K.-G.); (C.B.); (X.L.); (A.C.); (M.F.)
| | - Corinne Barbey
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (M.G.); (Y.B.); (Y.K.-G.); (C.B.); (X.L.); (A.C.); (M.F.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, F-76821 Mont-Saint-Aignan, France
| | - Xavier Latour
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (M.G.); (Y.B.); (Y.K.-G.); (C.B.); (X.L.); (A.C.); (M.F.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, F-76821 Mont-Saint-Aignan, France
| | - Andréa Chane
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (M.G.); (Y.B.); (Y.K.-G.); (C.B.); (X.L.); (A.C.); (M.F.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, F-76821 Mont-Saint-Aignan, France
| | - Marc Feuilloley
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (M.G.); (Y.B.); (Y.K.-G.); (C.B.); (X.L.); (A.C.); (M.F.)
| | - Annabelle Merieau
- LMSM, Laboratoire de Microbiologie Signaux et Microenvironnement, EA 4312, Normandy University, Université de Rouen, 27000 Evreux, France; (M.B.); (M.G.); (Y.B.); (Y.K.-G.); (C.B.); (X.L.); (A.C.); (M.F.)
- SFR NORVEGE, Structure Fédérative de Recherche Normandie Végétale, FED 4277, F-76821 Mont-Saint-Aignan, France
- Correspondence:
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17
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Ethanol Decreases Pseudomonas aeruginosa Flagellar Motility through the Regulation of Flagellar Stators. J Bacteriol 2019; 201:JB.00285-19. [PMID: 31109994 DOI: 10.1128/jb.00285-19] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2019] [Accepted: 05/17/2019] [Indexed: 12/16/2022] Open
Abstract
Pseudomonas aeruginosa frequently encounters microbes that produce ethanol. Low concentrations of ethanol reduced P. aeruginosa swim zone area by up to 45% in soft agar. The reduction of swimming by ethanol required the flagellar motor proteins MotAB and two PilZ domain proteins (FlgZ and PilZ). PilY1 and the type 4 pilus alignment complex (comprising PilMNOP) were previously implicated in MotAB regulation in surface-associated cells and were required for ethanol-dependent motility repression. As FlgZ requires the second messenger bis-(3'-5')-cyclic dimeric GMP (c-di-GMP) to represses motility, we screened mutants lacking genes involved in c-di-GMP metabolism and found that mutants lacking diguanylate cyclases SadC and GcbA were less responsive to ethanol. The double mutant was resistant to its effects. As published previously, ethanol also represses swarming motility, and the same genes required for ethanol effects on swimming motility were required for its regulation of swarming. Microscopic analysis of single cells in soft agar revealed that ethanol effects on swim zone area correlated with ethanol effects on the portion of cells that paused or stopped during the time interval analyzed. Ethanol increased c-di-GMP in planktonic wild-type cells but not in ΔmotAB or ΔsadC ΔgcbA mutants, suggesting c-di-GMP plays a role in the response to ethanol in planktonic cells. We propose that ethanol produced by other microbes induces a regulated decrease in P. aeruginosa motility, thereby promoting P. aeruginosa colocalization with ethanol-producing microbes. Furthermore, some of the same factors involved in the response to surface contact are involved in the response to ethanol.IMPORTANCE Ethanol is an important biologically active molecule produced by many bacteria and fungi. It has also been identified as a potential marker for disease state in cystic fibrosis. In line with previous data showing that ethanol promotes biofilm formation by Pseudomonas aeruginosa, here we report that ethanol reduces swimming motility using some of the same proteins involved in surface sensing. We propose that these data may provide insight into how microbes, via their metabolic byproducts, can influence P. aeruginosa colocalization in the context of infection and in other polymicrobial settings.
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18
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López-Baena FJ, Vinardell JM, Medina C. Regulation of Protein Secretion Systems Mediated by Cyclic Diguanylate in Plant-Interacting Bacteria. Front Microbiol 2019; 10:1289. [PMID: 31263457 PMCID: PMC6584795 DOI: 10.3389/fmicb.2019.01289] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 05/23/2019] [Indexed: 11/13/2022] Open
Abstract
The ubiquitous second messenger cyclic diguanylate (c-di-GMP) is involved in the regulation of different processes in bacteria. In phytopathogens, intracellular fluctuations in the concentration of this molecule contribute to the lifestyle switching from a motile and virulent stage to a sessile and biofilm-forming phase. Among the virulence mechanisms used by bacterial pathogens, different specific type secretion systems (TSSs) and the effector proteins that they translocate are included. Some of these TSS are conceived to suppress host immune responses during bacterial colonization. The modulation of the expression of secretion systems components and/or effector proteins can be influenced by c-di-GMP levels at transcriptional, translational, or post-translational levels and can take place directly by binding to specific or global regulators, or via transducer proteins. Different genera of plant-interacting bacteria have been analyzed to shed some light in the implications of c-di-GMP in the regulation of host plant colonization through protein secretion systems. Expression of (1) adhesins secreted by Type 1 secretion systems to bind the host plant in Pectobacterium (formerly Erwinia) and some beneficial Pseudomonas strains; (2) catalytic exoproteins delivered by Type 2 secretion systems to break plant cell wall in Dickeya; (3) effectors secreted by Type 3 secretion systems to suppress plant immunity in Xanthomonas; or (4) the activity of Type 6 secretion systems to export an ATPase in Pseudomonas, are finely tuned by c-di-GMP levels. In this minireview, we summarize the knowledge available about the implications of c-di-GMP in the regulation of protein secretion in different plant-interacting bacteria. Topic: Secretion systems and effector proteins of phytopathogenic and beneficial bacteria regulated by NSM.
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Affiliation(s)
| | - Jose María Vinardell
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
| | - Carlos Medina
- Departamento de Microbiología, Facultad de Biología, Universidad de Sevilla, Sevilla, Spain
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19
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Muriel C, Blanco-Romero E, Trampari E, Arrebola E, Durán D, Redondo-Nieto M, Malone JG, Martín M, Rivilla R. The diguanylate cyclase AdrA regulates flagellar biosynthesis in Pseudomonas fluorescens F113 through SadB. Sci Rep 2019; 9:8096. [PMID: 31147571 PMCID: PMC6543031 DOI: 10.1038/s41598-019-44554-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 05/14/2019] [Indexed: 11/23/2022] Open
Abstract
Flagellum mediated motility is an essential trait for rhizosphere colonization by pseudomonads. Flagella synthesis is a complex and energetically expensive process that is tightly regulated. In Pseudomonas fluorescens, the regulatory cascade starts with the master regulatory protein FleQ that is in turn regulated by environmental signals through the Gac/Rsm and SadB pathways, which converge in the sigma factor AlgU. AlgU is required for the expression of amrZ, encoding a FleQ repressor. AmrZ itself has been shown to modulate c-di-GMP levels through the control of many genes encoding enzymes implicated in c-di-GMP turnover. This cyclic nucleotide regulates flagellar function and besides, the master regulator of the flagellar synthesis signaling pathway, FleQ, has been shown to bind c-di-GMP. Here we show that AdrA, a diguanylate cyclase regulated by AmrZ participates in this signaling pathway. Epistasis analysis has shown that AdrA acts upstream of SadB, linking SadB with environmental signaling. We also show that SadB binds c-di-GMP with higher affinity than FleQ and propose that c-di-GMP produced by AdrA modulates flagella synthesis through SadB.
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Affiliation(s)
- Candela Muriel
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Esther Blanco-Romero
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Eleftheria Trampari
- Department of Molecular Microbiology, John Innes Centre. Colney Lane, Norwich, UK.,Quadram Institute, Norwich, UK
| | - Eva Arrebola
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain.,Department of Microbiology, University of Málaga, Málaga, Spain
| | - David Durán
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Miguel Redondo-Nieto
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Jacob G Malone
- Department of Molecular Microbiology, John Innes Centre. Colney Lane, Norwich, UK
| | - Marta Martín
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid, Campus de Cantoblanco, 28049, Madrid, Spain.
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20
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Abstract
Bacteria move by a variety of mechanisms, but the best understood types of motility are powered by flagella (72). Flagella are complex machines embedded in the cell envelope that rotate a long extracellular helical filament like a propeller to push cells through the environment. The flagellum is one of relatively few biological machines that experience continuous 360° rotation, and it is driven by one of the most powerful motors, relative to its size, on earth. The rotational force (torque) generated at the base of the flagellum is essential for motility, niche colonization, and pathogenesis. This review describes regulatory proteins that control motility at the level of torque generation.
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Affiliation(s)
- Sundharraman Subramanian
- Department of Chemistry, Indiana University, Bloomington, Indiana 47405, USA.,Biochemistry Graduate Program, Indiana University, Bloomington, Indiana 47405, USA
| | - Daniel B Kearns
- Department of Biology, Indiana University, Bloomington, Indiana 47405, USA;
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21
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Sun Y, Xie Z, Sui F, Liu X, Cheng W. Identification of Cbp1, a c-di-GMP Binding Chemoreceptor in Azorhizobium caulinodans ORS571 Involved in Chemotaxis and Nodulation of the Host Plant. Front Microbiol 2019; 10:638. [PMID: 31001223 PMCID: PMC6454048 DOI: 10.3389/fmicb.2019.00638] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 03/13/2019] [Indexed: 01/10/2023] Open
Abstract
Cbp1, a chemoreceptor containing a PilZ domain was identified in Azorhizobium caulinodans ORS571, a nitrogen-fixing free-living soil bacterium that induces nodule formation in both the roots and stems of the host legume Sesbania rostrata. Chemoreceptors are responsible for sensing signals in the chemotaxis pathway, which guides motile bacteria to beneficial niches and plays an important role in the establishment of rhizobia-legume symbiosis. PilZ domain proteins are known to bind the second messenger c-di-GMP, an important regulator of motility, biofilm formation and virulence. Cbp1 was shown to bind c-di-GMP through the conserved RxxxR motif of its PilZ domain. A mutant strain carrying a cbp1 deletion was impaired in chemotaxis, a feature that could be restored by genetic complementation. Compared with the wild type strain, the Δcbp1 mutant displayed enhanced aggregation and biofilm formation. The Δcbp1 mutant induced functional nodules when inoculated individually. However, the Δcbp1 mutant was less competitive than the wild type in competitive root colonization and nodulation. These data are in agreement with the hypothesis that the c-di-GMP binding chemoreceptor Cbp1 in A. caulinodans is involved in chemotaxis and nodulation.
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Affiliation(s)
- Yu Sun
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Zhihong Xie
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, China
| | - Fu Sui
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaolin Liu
- Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China.,College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China
| | - Wuzeng Cheng
- Shandong Huibang Bohai Agriculture Development Limited Company, Dongying, China
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22
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Bense S, Bruchmann S, Steffen A, Stradal TEB, Häussler S, Düvel J. Spatiotemporal control of FlgZ activity impacts Pseudomonas aeruginosa flagellar motility. Mol Microbiol 2019; 111:1544-1557. [PMID: 30864240 DOI: 10.1111/mmi.14236] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/07/2019] [Indexed: 12/25/2022]
Abstract
The c-di-GMP-binding effector protein FlgZ has been demonstrated to control motility in the opportunistic pathogen Pseudomonas aeruginosa and it was suggested that c-di-GMP-bound FlgZ impedes motility via its interaction with the MotCD stator. To further understand how motility is downregulated in P. aeruginosa and to elucidate the general control mechanisms operating during bacterial growth, we examined the spatiotemporal activity of FlgZ. We re-annotated the P. aeruginosaflgZ open reading frame and demonstrated that FlgZ-mediated downregulation of motility is fine-tuned via three independent mechanisms. First, we found that flgZ gene is transcribed independently from flgMN in stationary growth phase to increase FlgZ protein levels in the cell. Second, FlgZ localizes to the cell pole upon c-di-GMP binding and third, we describe that FimV, a cell pole anchor protein, is involved in increasing the polar localized c-di-GMP bound FlgZ to inhibit both, swimming and swarming motility. Our results shed light on the complex dynamics and spatiotemporal control of c-di-GMP-dependent bacterial motility phenotypes and on how the polar anchor protein FimV, the motor brake FlgZ and the stator proteins function to repress flagella-driven swimming and swarming motility.
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Affiliation(s)
- Sarina Bense
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, Inhoffenstr. 7, Braunschweig, 38124, Germany
| | - Sebastian Bruchmann
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, Inhoffenstr. 7, Braunschweig, 38124, Germany
| | - Anika Steffen
- Department of Cell Biology, Helmholtz Center for Infection Research, Inhoffenstr. 7, Braunschweig, 38124, Germany
| | - Theresia E B Stradal
- Department of Cell Biology, Helmholtz Center for Infection Research, Inhoffenstr. 7, Braunschweig, 38124, Germany
| | - Susanne Häussler
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, Inhoffenstr. 7, Braunschweig, 38124, Germany
| | - Juliane Düvel
- Department of Molecular Bacteriology, Helmholtz Center for Infection Research, Inhoffenstr. 7, Braunschweig, 38124, Germany
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23
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The GGDEF Domain of the Phosphodiesterase PdeB in Shewanella putrefaciens Mediates Recruitment by the Polar Landmark Protein HubP. J Bacteriol 2019; 201:JB.00534-18. [PMID: 30670544 DOI: 10.1128/jb.00534-18] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Accepted: 12/21/2018] [Indexed: 12/13/2022] Open
Abstract
Bacteria commonly exhibit a high degree of cellular organization and polarity which affect many vital processes such as replication, cell division, and motility. In Shewanella and other bacteria, HubP is a polar marker protein which is involved in proper chromosome segregation, placement of the chemotaxis system, and various aspects of pilus- and flagellum-mediated motility. Here, we show that HubP also recruits a transmembrane multidomain protein, PdeB, to the flagellated cell pole. PdeB is an active phosphodiesterase and degrades the second messenger c-di-GMP. In Shewanella putrefaciens, PdeB affects both the polar and the lateral flagellar systems at the level of function and/or transcription in response to environmental medium conditions. Mutant analysis on fluorescently labeled PdeB indicated that a diguanylate cyclase (GGDEF) domain in PdeB is strictly required for HubP-dependent localization. Bacterial two-hybrid and in vitro interaction studies on purified proteins strongly indicate that this GGDEF domain of PdeB directly interacts with the C-terminal FimV domain of HubP. Polar localization of PdeB occurs late during the cell cycle after cell division and separation and is not dependent on medium conditions. In vitro activity measurements did not reveal a difference in PdeB phosphodiesterase activities in the presence or absence of the HubP FimV domain. We hypothesize that recruitment of PdeB to the flagellated pole by HubP may create an asymmetry of c-di-GMP levels between mother and daughter cells and may assist in organization of c-di-GMP-dependent regulation within the cell.IMPORTANCE c-di-GMP-dependent signaling affects a range of processes in many bacterial species. Most bacteria harbor a plethora of proteins with domains which are potentially involved in synthesis and breakdown of c-di-GMP. A potential mechanism to elicit an appropriate c-di-GMP-dependent response is to organize the corresponding proteins in a spatiotemporal fashion. Here, we show that a major contributor to c-di-GMP levels and flagellum-mediated swimming in Shewanella, PdeB, is recruited to the flagellated cell pole by the polar marker protein HubP. Polar recruitment involves a direct interaction between HubP and a GGDEF domain in PdeB, demonstrating a novel mechanism of polar targeting by the widely conserved HubP/FimV polar marker.
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24
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Wang Y, Wang X, Ali F, Li Z, Fu Y, Yang X, Lin W, Lin X. Comparative Extracellular Proteomics of Aeromonas hydrophila Reveals Iron-Regulated Secreted Proteins as Potential Vaccine Candidates. Front Immunol 2019; 10:256. [PMID: 30833947 PMCID: PMC6387970 DOI: 10.3389/fimmu.2019.00256] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 01/29/2019] [Indexed: 01/07/2023] Open
Abstract
In our previous study, several iron-related outer membrane proteins in Aeromonas hydrophila, a serious pathogen of farmed fish, conferred high immunoprotectivity to fish, and were proposed as potential vaccine candidates. However, the protective efficacy of these extracellular proteins against A. hydrophila remains largely unknown. Here, we identified secreted proteins that were differentially expressed in A. hydrophila LP-2 in response to iron starvation using an iTRAQ-based quantitative proteomics method. We identified 341 proteins, of which 9 were upregulated in response to iron starvation and 24 were downregulated. Many of the differently expressed proteins were associated with protease activity. We confirmed our proteomics results with Western blotting and qPCR. We constructed three mutants by knocking out three genes encoding differentially expressed proteins (Δorf01830, Δorf01609, and Δorf03641). The physiological characteristics of these mutants were investigated. In all these mutant strains, protease activity decreased, and Δorf01609, and Δorf01830 were less virulent in zebrafish. This indicated that the proteins encoded by these genes may play important roles in bacterial infection. We next evaluated the immune response provoked by the six iron-related recombinant proteins (ORF01609, ORF01830, ORF01839, ORF02943, ORF03355, and ORF03641) in zebrafish as well as the immunization efficacy of these proteins. Immunization with these proteins significantly increased the zebrafish immune response. In addition, the relative percent survival (RPS) of the immunized zebrafish was 50-80% when challenged with three virulent A. hydrophila strains, respectively. Thus, these extracellular secreted proteins might be effective vaccine candidates against A. hydrophila infection in fish.
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Affiliation(s)
- Yuqian Wang
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaoyun Wang
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou, China
| | - Farman Ali
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou, China
| | - Zeqi Li
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou, China
| | - Yuying Fu
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou, China
| | - Xiaojun Yang
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou, China
| | - Wenxiong Lin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou, China
| | - Xiangmin Lin
- Fujian Provincial Key Laboratory of Agroecological Processing and Safety Monitoring, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, China.,Key Laboratory of Crop Ecology and Molecular Physiology, Fujian Agriculture and Forestry University, Fujian Province University, Fuzhou, China
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25
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Emerging paradigms for PilZ domain-mediated C-di-GMP signaling. Biochem Soc Trans 2019; 47:381-388. [PMID: 30710060 DOI: 10.1042/bst20180543] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Revised: 01/02/2019] [Accepted: 01/08/2019] [Indexed: 11/17/2022]
Abstract
PilZ domain-containing proteins constitute a large family of bacterial signaling proteins. As a widely distributed protein domain for the binding of the second messenger c-di-GMP, the canonical PilZ domain contains a set of motifs that define the binding site for c-di-GMP and an allosteric switch for propagating local conformational changes. Here, we summarize some new insights gathered from recent studies on the commonly occurring single-domain PilZ proteins, YcgR-like proteins and PilZ domain-containing cellulose synthases. The studies collectively illuminate how PilZ domains function as cis- or trans-regulatory domains that enable c-di-GMP to control the activity of its cellular targets. Overall, the review highlights the diverse protein structure, biological function and regulatory mechanism of PilZ domain-containing proteins, as well as the challenge of deciphering the function and mechanism of orphan PilZ proteins.
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26
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Ogunyemi SO, Fang Y, Qiu W, Li B, Chen J, Yang M, Hong X, Luo J, Wang Y, Sun G. Role of type IV secretion system genes in virulence of rice bacterial brown stripe pathogen Acidovorax oryzae strain RS-2. Microb Pathog 2018; 126:343-350. [PMID: 30468852 DOI: 10.1016/j.micpath.2018.11.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 11/12/2018] [Accepted: 11/12/2018] [Indexed: 10/27/2022]
Abstract
Type IV secretion system (T4SS) is a specialized nanomachine that is utilized for the pathogenicity of gram-negative bacteria. However, the role of T4SS genes in virulence of rice bacterial brown stripe pathogen Acidovorax oryzae (Ao) strain RS-2 is not clear, which contains T4SS gene cluster based on genome-wide analysis. Here we compared the virulence-related phenotypes between the wild-type strain RS-2 and nine T4SS mutants, which were constructed in this study. Results indicated that mutation of pilT, pilM, pilQ, or pilZ3 genes not only significantly reduced bacterial virulence, but also caused a reduction of 20.4-62.0% in biofilm formation and 37.7-47.7% reduction in motility, but had no effect on exopolysaccharide (EPS) production or extracellular enzymatic activities when compared to the wild type. The four T4SS genes had a differential effect on bacterial growth after 24 h post-incubation. The complemented strains of the four T4SS mutants restored similar virulence symptom as the wild type. In addition, no change was observed in bacterial virulence by mutation of the other five T4SS genes. Totally, these results demonstrated that T4SS played vital roles in bacterial virulence, motility and biofilm formation in plant pathogen Ao strain RS-2.
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Affiliation(s)
- Solabomi Olaitan Ogunyemi
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China; Department of Crop Protection, Federal University of Agriculture Abeokuta, Abeokuta, Nigeria
| | - 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, 310058, Hangzhou, 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, 310058, Hangzhou, 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, 310058, Hangzhou, 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, 310058, Hangzhou, China
| | - Min 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, 310058, Hangzhou, China
| | - Xianxian Hong
- State Key Laboratory of Rice Biology, Ministry of Agriculture Key Lab of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology, Zhejiang University, 310058, Hangzhou, China
| | - Jinyan Luo
- Department of Plant Quarantine, Shanghai Extension and Service Center of Agriculture Technology, Shanghai 201103, China
| | - Yangli Wang
- State Key Laboratory Breeding Base for Zhejiang Sustainable Pest and Disease Control, Institute of Plant Protection and Microbiology, Zhejiang Academy of Agricultural Sciences, 310021, Hangzhou, 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, 310021, Hangzhou, China
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27
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Blanco-Romero E, Redondo-Nieto M, Martínez-Granero F, Garrido-Sanz D, Ramos-González MI, Martín M, Rivilla R. Genome-wide analysis of the FleQ direct regulon in Pseudomonas fluorescens F113 and Pseudomonas putida KT2440. Sci Rep 2018; 8:13145. [PMID: 30177764 PMCID: PMC6120874 DOI: 10.1038/s41598-018-31371-z] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/08/2018] [Indexed: 12/20/2022] Open
Abstract
Bacterial motility plays a crucial role in competitiveness and colonization in the rhizosphere. In this work, Chromatin ImmunoPrecipitation Sequencing (ChIP-seq) analysis has been used to identify genes putatively regulated by the transcriptional regulatory protein FleQ in Pseudomonas fluorescens F113 and Pseudomonas putida KT2440. This protein was previously identified as a master regulator of flagella and biofilm formation in both strains. This work has demonstrated that FleQ from both bacteria are conserved and functionally equivalent for motility regulation. Furthermore, the ChIP-seq analysis has shown that FleQ is a global regulator with the identification of 121 and 103 FleQ putative binding sites in P. fluorescens F113 and P. putida KT2440 respectively. Putative genes regulated by FleQ included, as expected, flagellar and motility-related genes and others involved in adhesion and exopolysaccharide production. Surprisingly, the ChIP-seq analysis also identified iron homeostasis-related genes for which positive regulation was shown by RT-qPCR. The results also showed that FleQ from P. fluorescens F113 shares an important part of its direct regulon with AmrZ, a global regulator also implicated in environmental adaption. Although AmrZ also regulates motility and iron uptake, the overlap occurred mostly with the iron-related genes, since both regulators control a different set of motility-related genes.
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Affiliation(s)
- Esther Blanco-Romero
- 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
| | - Francisco Martínez-Granero
- 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
| | - Maria Isabel Ramos-González
- Departamento de Protección Ambiental. Grupo de Microbiología Ambiental y Biodegradación, Estación Experimental del Zaidín, CSIC, Profesor Albareda, 1, 18008, Granada, Spain
| | - Marta Martín
- 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.
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28
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PP4397/FlgZ provides the link between PP2258 c-di-GMP signalling and altered motility in Pseudomonas putida. Sci Rep 2018; 8:12205. [PMID: 30111852 PMCID: PMC6093933 DOI: 10.1038/s41598-018-29785-w] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 07/18/2018] [Indexed: 01/01/2023] Open
Abstract
Bacteria swim and swarm using rotating flagella that are driven by a membrane-spanning motor complex. Performance of the flagella motility apparatus is modulated by the chemosensory signal transduction system to allow navigation through physico-chemical gradients - a process that can be fine-tuned by the bacterial second messenger c-di-GMP. We have previously analysed the Pseudomonas putida signalling protein PP2258 that has the capacity to both synthesize and degrade c-di-GMP. A PP2258 null mutant displays reduced motility, implicating the c-di-GMP signal originating from this protein in control of P. putida motility. In Escherichia coli and Salmonella, the PilZ-domain protein YcgR mediates c-di-GMP responsive control of motility through interaction with the flagellar motors. Here we provide genetic evidence that the P. putida protein PP4397 (also known as FlgZ), despite low sequence homology and a different genomic context to YcgR, functions as a c-di-GMP responsive link between the signal arising from PP2258 and alterations in swimming and swarming motility in P. putida.
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29
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Muriel C, Arrebola E, Redondo-Nieto M, Martínez-Granero F, Jalvo B, Pfeilmeier S, Blanco-Romero E, Baena I, Malone JG, Rivilla R, Martín M. AmrZ is a major determinant of c-di-GMP levels in Pseudomonas fluorescens F113. Sci Rep 2018; 8:1979. [PMID: 29386661 PMCID: PMC5792552 DOI: 10.1038/s41598-018-20419-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Accepted: 01/18/2018] [Indexed: 01/17/2023] Open
Abstract
The transcriptional regulator AmrZ is a global regulatory protein conserved within the pseudomonads. AmrZ can act both as a positive and a negative regulator of gene expression, controlling many genes implicated in environmental adaption. Regulated traits include motility, iron homeostasis, exopolysaccharides production and the ability to form biofilms. In Pseudomonas fluorescens F113, an amrZ mutant presents a pleiotropic phenotype, showing increased swimming motility, decreased biofilm formation and very limited ability for competitive colonization of rhizosphere, its natural habitat. It also shows different colony morphology and binding of the dye Congo Red. The amrZ mutant presents severely reduced levels of the messenger molecule cyclic-di-GMP (c-di-GMP), which is consistent with the motility and biofilm formation phenotypes. Most of the genes encoding proteins with diguanylate cyclase (DGCs) or phosphodiesterase (PDEs) domains, implicated in c-di-GMP turnover in this bacterium, appear to be regulated by AmrZ. Phenotypic analysis of eight mutants in genes shown to be directly regulated by AmrZ and encoding c-di-GMP related enzymes, showed that seven of them were altered in motility and/or biofilm formation. The results presented here show that in P. fluorescens, AmrZ determines c-di-GMP levels through the regulation of a complex network of genes encoding DGCs and PDEs.
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Affiliation(s)
- Candela Muriel
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Eva Arrebola
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Miguel Redondo-Nieto
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | | | - Blanca Jalvo
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Sebastian Pfeilmeier
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, NR47UH, Norwich, UK
| | - Esther Blanco-Romero
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Irene Baena
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Jacob G Malone
- Department of Molecular Microbiology, John Innes Centre, Colney Lane, NR47UH, Norwich, UK
| | - Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Universidad Autónoma de Madrid, Darwin, 2, 28034, Madrid, Spain.
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30
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Castiblanco LF, Sundin GW. Cellulose production, activated by cyclic di-GMP through BcsA and BcsZ, is a virulence factor and an essential determinant of the three-dimensional architectures of biofilms formed by Erwinia amylovora Ea1189. MOLECULAR PLANT PATHOLOGY 2018; 19:90-103. [PMID: 27753193 PMCID: PMC6638026 DOI: 10.1111/mpp.12501] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Revised: 10/10/2016] [Accepted: 10/13/2016] [Indexed: 05/04/2023]
Abstract
Bacterial biofilms are multicellular aggregates encased in an extracellular matrix mainly composed of exopolysaccharides (EPSs), protein and nucleic acids, which determines the architecture of the biofilm. Erwinia amylovora Ea1189 forms a biofilm inside the xylem of its host, which results in vessel plugging and water transport impairment. The production of the EPSs amylovoran and levan is critical for the formation of a mature biofilm. In addition, cyclic dimeric GMP (c-di-GMP) has been reported to positively regulate amylovoran biosynthesis and biofilm formation in E. amylovora Ea1189. In this study, we demonstrate that cellulose is synthesized by E. amylovora Ea1189 and is a major modulator of the three-dimensional characteristics of biofilms formed by this bacterium, and also contributes to virulence during systemic host invasion. In addition, we demonstrate that the activation of cellulose biosynthesis in E. amylovora is a c-di-GMP-dependent process, through allosteric binding to the cellulose catalytic subunit BcsA. We also report that the endoglucanase BcsZ is a key player in c-di-GMP activation of cellulose biosynthesis. Our results provide evidence of the complex composition of the extracellular matrix produced by E. amylovora and the implications of cellulose biosynthesis in shaping the architecture of the biofilm and in the expression of one of the main virulence phenotypes of this pathogen.
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Affiliation(s)
- Luisa F. Castiblanco
- Department of Plant, Soil and Microbial Sciences and Center for Microbial PathogenesisMichigan State UniversityEast LansingMI48824USA
| | - George W. Sundin
- Department of Plant, Soil and Microbial Sciences and Center for Microbial PathogenesisMichigan State UniversityEast LansingMI48824USA
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31
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Abstract
Cyclic diguanylate (c-di-GMP) is a near universal signaling molecule produced by diguanylate cyclases that can direct a variety of bacterial behaviors. A major area of research over the last several years has been aimed at understanding how a cell with dozens of diguanylate cyclases can deploy a given subset of them to produce a desired phenotypic outcome without undesired cross talk between c-di-GMP-dependent systems. Several models have been put forward to address this question, including specificity of cyclase activation, tuned binding constants of effector proteins, and physical interaction between cyclases and effectors. Additionally, recent evidence has suggested that there may be a link between the catalytic state of a cyclase and its physical contact with an effector. This review highlights several key studies, examines the proposed global and local models of c-di-GMP signaling specificity in bacteria, and attempts to identify the most fruitful steps that can be taken to better understand how dynamic networks of sibling cyclases and effector proteins result in sensible outputs that govern cellular behavior.
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Affiliation(s)
- Kurt M Dahlstrom
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755;
| | - George A O'Toole
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755;
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Sadiq FA, Flint S, Li Y, Liu T, Lei Y, Sakandar HA, He G. New mechanistic insights into the motile-to-sessile switch in various bacteria with particular emphasis on Bacillus subtilis and Pseudomonas aeruginosa: a review. BIOFOULING 2017; 33:306-326. [PMID: 28347177 DOI: 10.1080/08927014.2017.1304541] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Accepted: 03/04/2017] [Indexed: 06/06/2023]
Abstract
A biofilm is a complex assemblage of microbial communities adhered to a biotic or an abiotic surface which is embedded within a self-produced matrix of extracellular polymeric substances. Many transcriptional regulators play a role in triggering a motile-sessile switch and in consequently producing the biofilm matrix. This review is aimed at highlighting the role of two nucleotide signaling molecules (c-di-GMP and c-di-AMP), toxin antitoxin modules and a novel transcriptional regulator BolA in biofilm formation in various bacteria. In addition, it highlights the common themes that have appeared in recent research regarding the key regulatory components and signal transduction pathways that help Bacillus subtilis and Pseudomonas aeruginosa to acquire the biofilm mode of life.
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Affiliation(s)
- Faizan A Sadiq
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | - Steve Flint
- b School of Food and Nutrition , Massey University , Palmerston North , New Zealand
| | - Yun Li
- c School of Life Sciences and Food Technology , Hanshan Normal University , Chaozhou , PR China
| | - TongJie Liu
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | - Yuan Lei
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
| | | | - GuoQing He
- a College of Biosystems Engineering and Food Science , Zhejiang University , Hangzhou , PR China
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Abstract
Cyclic dinucleotides (CDNs) are highly versatile signalling molecules that control various important biological processes in bacteria. The best-studied example is cyclic di-GMP (c-di-GMP). Known since the late 1980s, it is now recognized as a near-ubiquitous second messenger that coordinates diverse aspects of bacterial growth and behaviour, including motility, virulence, biofilm formation and cell cycle progression. In this Review, we discuss important new insights that have been gained into the molecular principles of c-di-GMP synthesis and degradation, which are mediated by diguanylate cyclases and c-di-GMP-specific phosphodiesterases, respectively, and the cellular functions that are exerted by c-di-GMP-binding effectors and their diverse targets. Finally, we provide a short overview of the signalling versatility of other CDNs, including c-di-AMP and cGMP-AMP (cGAMP).
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The Diguanylate Cyclase HsbD Intersects with the HptB Regulatory Cascade to Control Pseudomonas aeruginosa Biofilm and Motility. PLoS Genet 2016; 12:e1006354. [PMID: 27792789 PMCID: PMC5085249 DOI: 10.1371/journal.pgen.1006354] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2016] [Accepted: 09/09/2016] [Indexed: 11/19/2022] Open
Abstract
The molecular basis of second messenger signaling relies on an array of proteins that synthesize, degrade or bind the molecule to produce coherent functional outputs. Cyclic di-GMP (c-di-GMP) has emerged as a eubacterial nucleotide second messenger regulating a plethora of key behaviors, like the transition from planktonic cells to biofilm communities. The striking multiplicity of c-di-GMP control modules and regulated cellular functions raised the question of signaling specificity. Are c-di-GMP signaling routes exclusively dependent on a central hub or can they be locally administrated? In this study, we show an example of how c-di-GMP signaling gains output specificity in Pseudomonas aeruginosa. We observed the occurrence in P. aeruginosa of a c-di-GMP synthase gene, hsbD, in the proximity of the hptB and flagellar genes cluster. We show that the HptB pathway controls biofilm formation and motility by involving both HsbD and the anti-anti-sigma factor HsbA. The rewiring of c-di-GMP signaling into the HptB cascade relies on the original interaction between HsbD and HsbA and on the control of HsbD dynamic localization at the cell poles.
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Xiao Y, Liu H, Nie H, Xie S, Luo X, Chen W, Huang Q. Expression of the phosphodiesterase BifA facilitating swimming motility is partly controlled by FliA in Pseudomonas putida KT2440. Microbiologyopen 2016; 6. [PMID: 27663176 PMCID: PMC5300878 DOI: 10.1002/mbo3.402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2016] [Revised: 08/12/2016] [Accepted: 08/19/2016] [Indexed: 12/30/2022] Open
Abstract
Flagella‐mediated motility is an important capability of many bacteria to survive in nutrient‐depleted and harsh environments. Decreasing the intracellular cyclic di‐GMP (c‐di‐GMP) level by overexpression of phosphodiesterase BifA promotes flagellar‐mediated motility and induces planktonic lifestyle in Pseudomonas. The mechanism that regulates expression of bifA gene was poorly studied. Here we showed that expression of BifA was partly controlled by flagellar sigma factor FliA (σ28) in Pseudomonas putidaKT2440. FliA deletion led to an approximately twofold decrease in transcription of bifA. 5′ race assay revealed two transcription start points in bifA promoter region, with the putative σ70 and σ28 promoter sequences upstream, respectively. Point mutation in σ28 promoter region reduced transcriptional activity of the promoter in wild‐type KT2440, but showed no influence on that in fliA deletion mutant. FliA overexpression decreased the intracellular c‐di‐GMP level in a BifA‐dependent way, suggesting that FliA was able to modulate the intracellular c‐di‐GMP level and BifA function was required for the modulation. Besides, FliA overexpression enhanced swimming ability of wild‐type strain, while made no difference to the bifA mutant. Our results suggest that FliA acts as a negative regulator to modulate the c‐di‐GMP level via controlling transcription of bifA to facilitate swimming motility.
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Affiliation(s)
- Yujie Xiao
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Huizhong Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Hailing Nie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Shan Xie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Xuesong Luo
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, China
| | - Wenli Chen
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Qiaoyun Huang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China.,Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtze River), Ministry of Agriculture, College of Resources and Environment, Huazhong Agricultural University, Wuhan, China
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36
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Combating chronic bacterial infections by manipulating cyclic nucleotide-regulated biofilm formation. Future Med Chem 2016; 8:949-61. [PMID: 27304227 DOI: 10.4155/fmc-2015-0002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Many pathogenic bacteria can form biofilms in clinical settings with major consequences for the progression of infections. Bacterial biofilm communities are typically much more resistant to both antibiotic treatment and clearance by the immune system in comparison to free-living cells. Therefore, drugs that specifically target the formation or maintenance of biofilms would be very valuable additions to current clinical options. Cyclic nucleotide second messengers, in particular cyclic-diguanosine-GMP (c-di-GMP), are now known to play a major role in biofilm formation, and maintenance, in many bacterial species. In this special report, we will review recent progress toward the development of drugs that interfere with c-di-GMP signaling as a route to control biofilm infections. We will focus on the chronic infections associated with the notorious opportunistic pathogen Pseudomonas aeruginosa, although the principles outlined here are also relevant to most bacterial pathogens.
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PilZ Domain Protein FlgZ Mediates Cyclic Di-GMP-Dependent Swarming Motility Control in Pseudomonas aeruginosa. J Bacteriol 2016; 198:1837-46. [PMID: 27114465 DOI: 10.1128/jb.00196-16] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 04/21/2016] [Indexed: 01/29/2023] Open
Abstract
UNLABELLED The second messenger cyclic diguanylate (c-di-GMP) is an important regulator of motility in many bacterial species. In Pseudomonas aeruginosa, elevated levels of c-di-GMP promote biofilm formation and repress flagellum-driven swarming motility. The rotation of P. aeruginosa's polar flagellum is controlled by two distinct stator complexes, MotAB, which cannot support swarming motility, and MotCD, which promotes swarming motility. Here we show that when c-di-GMP levels are elevated, swarming motility is repressed by the PilZ domain-containing protein FlgZ and by Pel polysaccharide production. We demonstrate that FlgZ interacts specifically with the motility-promoting stator protein MotC in a c-di-GMP-dependent manner and that a functional green fluorescent protein (GFP)-FlgZ fusion protein shows significantly reduced polar localization in a strain lacking the MotCD stator. Our results establish FlgZ as a c-di-GMP receptor affecting swarming motility by P. aeruginosa and support a model wherein c-di-GMP-bound FlgZ impedes motility via its interaction with the MotCD stator. IMPORTANCE The regulation of surface-associated motility plays an important role in bacterial surface colonization and biofilm formation. c-di-GMP signaling is a widespread means of controlling bacterial motility, and yet the mechanism whereby this signal controls surface-associated motility in P. aeruginosa remains poorly understood. Here we identify a PilZ domain-containing c-di-GMP effector protein that contributes to c-di-GMP-mediated repression of swarming motility by P. aeruginosa We provide evidence that this effector, FlgZ, impacts swarming motility via its interactions with flagellar stator protein MotC. Thus, we propose a new mechanism for c-di-GMP-mediated regulation of motility for a bacterium with two flagellar stator sets, increasing our understanding of surface-associated behaviors, a key prerequisite to identifying ways to control the formation of biofilm communities.
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c-di-GMP and its Effects on Biofilm Formation and Dispersion: a Pseudomonas Aeruginosa Review. Microbiol Spectr 2016; 3:MB-0003-2014. [PMID: 26104694 DOI: 10.1128/microbiolspec.mb-0003-2014] [Citation(s) in RCA: 185] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Since its initial discovery as an allosteric factor regulating cellulose biosynthesis in Gluconacetobacter xylinus, the list of functional outputs regulated by c-di-GMP has grown. We have focused this article on one of these c-di-GMP-regulated processes, namely, biofilm formation in the organism Pseudomonas aeruginosa. The majority of diguanylate cyclases and phosphodiesterases encoded in the P. aeruginosa genome still remain uncharacterized; thus, there is still a great deal to be learned about the link between c-di-GMP and biofilm formation in this microbe. In particular, while a number of c-di-GMP metabolizing enzymes have been identified that participate in reversible and irreversible attachment and biofilm maturation, there is a still a significant knowledge gap regarding the c-di-GMP output systems in this organism. Even for the well-characterized Pel system, where c-di-GMP-mediated transcriptional regulation is now well documented, how binding of c-di-GMP by PelD stimulates Pel production is not understood in any detail. Similarly, c-di-GMP-mediated control of swimming, swarming and twitching also remains to be elucidated. Thus, despite terrific advances in our understanding of P. aeruginosa biofilm formation and the role of c-di-GMP in this process since the last version of this book (indeed there was no chapter on c-di-GMP!) there is still much to learn.
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Prada-Ramírez HA, Pérez-Mendoza D, Felipe A, Martínez-Granero F, Rivilla R, Sanjuán J, Gallegos MT. AmrZ regulates cellulose production in Pseudomonas syringae pv. tomato DC3000. Mol Microbiol 2015; 99:960-77. [PMID: 26564578 DOI: 10.1111/mmi.13278] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/11/2015] [Indexed: 11/27/2022]
Abstract
In Pseudomonas syringae pv. tomato DC3000, the second messenger c-di-GMP has been previously shown to stimulate pellicle formation and cellulose biosynthesis. A screen for genes involved in cellulose production under high c-di-GMP intracellular levels led to the identification of insertions in two genes, wssB and wssE, belonging to the Pto DC3000 cellulose biosynthesis operon wssABCDEFGHI. Interestingly, beside cellulose-deficient mutants, colonies with a rougher appearance than the wild type also arouse among the transposants. Those mutants carry insertions in amrZ, a gene encoding a transcriptional regulator in different Pseudomonas. Here, we provide evidence that AmrZ is involved in the regulation of bacterial cellulose production at transcriptional level by binding to the promoter region of the wssABCDEFGHI operon and repressing cellulose biosynthesis genes. Mutation of amrZ promotes wrinkly colony morphology, increased cellulose production and loss of motility in Pto DC3000. AmrZ regulon includes putative c-di-GMP metabolising proteins, like AdcA and MorA, which may also impact those phenotypes. Furthermore, an amrZ but not a cellulose-deficient mutant turned out to be impaired in pathogenesis, indicating that AmrZ is a key regulator of Pto DC3000 virulence probably by controlling bacterial processes other than cellulose production.
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Affiliation(s)
- Harold A Prada-Ramírez
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain
| | - Daniel Pérez-Mendoza
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain
| | - Antonia Felipe
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain
| | | | - Rafael Rivilla
- Department of Biology, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
| | - Juan Sanjuán
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain
| | - María-Trinidad Gallegos
- Department of Soil Microbiology and Symbiotic Systems, Estación Experimental del Zaidín (EEZ-CSIC), Granada, Spain
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40
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Cyclic Di-GMP Regulates Multiple Cellular Functions in the Symbiotic Alphaproteobacterium Sinorhizobium meliloti. J Bacteriol 2015; 198:521-35. [PMID: 26574513 DOI: 10.1128/jb.00795-15] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 11/09/2015] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Sinorhizobium meliloti undergoes major lifestyle changes between planktonic states, biofilm formation, and symbiosis with leguminous plant hosts. In many bacteria, the second messenger 3',5'-cyclic di-GMP (c-di-GMP, or cdG) promotes a sessile lifestyle by regulating a plethora of processes involved in biofilm formation, including motility and biosynthesis of exopolysaccharides (EPS). Here, we systematically investigated the role of cdG in S. meliloti Rm2011 encoding 22 proteins putatively associated with cdG synthesis, degradation, or binding. Single mutations in 21 of these genes did not cause evident changes in biofilm formation, motility, or EPS biosynthesis. In contrast, manipulation of cdG levels by overproducing endogenous or heterologous diguanylate cyclases (DGCs) or phosphodiesterases (PDEs) affected these processes and accumulation of N-Acyl-homoserine lactones in the culture supernatant. Specifically, individual overexpression of the S. meliloti genes pleD, SMb20523, SMb20447, SMc01464, and SMc03178 encoding putative DGCs and of SMb21517 encoding a single-domain PDE protein had an impact and resulted in increased levels of cdG. Compared to the wild type, an S. meliloti strain that did not produce detectable levels of cdG (cdG(0)) was more sensitive to acid stress. However, it was symbiotically potent, unaffected in motility, and only slightly reduced in biofilm formation. The SMc01790-SMc01796 locus, homologous to the Agrobacterium tumefaciens uppABCDEF cluster governing biosynthesis of a unipolarly localized polysaccharide, was found to be required for cdG-stimulated biofilm formation, while the single-domain PilZ protein McrA was identified as a cdG receptor protein involved in regulation of motility. IMPORTANCE We present the first systematic genome-wide investigation of the role of 3',5'-cyclic di-GMP (c-di-GMP, or cdG) in regulation of motility, biosynthesis of exopolysaccharides, biofilm formation, quorum sensing, and symbiosis in a symbiotic alpha-rhizobial species. Phenotypes of an S. meliloti strain unable to produce cdG (cdG(0)) demonstrated that this second messenger is not essential for root nodule symbiosis but may contribute to acid tolerance. Our data further suggest that enhanced levels of cdG promote sessility of S. meliloti and uncovered a single-domain PilZ protein as regulator of motility.
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41
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Schmutzler K, Kracht ON, Schmid A, Buehler K. Trophic regulation of autoaggregation in Pseudomonas taiwanensis VLB120. Appl Microbiol Biotechnol 2015; 100:347-60. [PMID: 26428239 DOI: 10.1007/s00253-015-7006-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2015] [Revised: 09/03/2015] [Accepted: 09/12/2015] [Indexed: 01/01/2023]
Abstract
Five mutants of Pseudomonas taiwanensis VLB120ΔCeGFP showed significant autoaggregation when growing on defined carbohydrates or gluconate, while they grew as suspended cells on complex medium and on organic acids like citrate and succinate. Surprisingly, the respective mutations affected very different genes, although all five strains exhibited the same behaviour of aggregate formation. To elucidate the mechanism of the aggregative behaviour, the microbial adhesion to hydrocarbons (MATH) assay and contact angle measurements were performed that pointed to an increased cell surface hydrophobicity. Moreover, investigations of the outer layer of the cell membrane revealed a reduced amount of O-specific polysaccharides in the lipopolysaccharide of the mutant cells. To determine the regulation of the aggregation, reverse transcription quantitative real-time PCR was performed and, irrespective of the mutation, the transcription of a gene encoding a putative phosphodiesterase, which is degrading the global second messenger cyclic diguanylate, was decreased or even deactivated in all mutants. In summary, it appears that the trophic autoaggregation was regulated via cyclic diguanylate and a link between the cellular cyclic diguanylate concentration and the lipopolysaccharide composition of P. taiwanensis VLB120ΔCeGFP is suggested.
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Affiliation(s)
- Karolin Schmutzler
- Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Strasse 66, 44227, Dortmund, Germany
- Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Octavia Natascha Kracht
- Laboratory of Chemical Biotechnology, Department of Biochemical and Chemical Engineering, TU Dortmund University, Emil-Figge-Strasse 66, 44227, Dortmund, Germany
| | - Andreas Schmid
- Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany
| | - Katja Buehler
- Department of Solar Materials, Helmholtz-Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318, Leipzig, Germany.
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Trampari E, Stevenson CEM, Little RH, Wilhelm T, Lawson DM, Malone JG. Bacterial rotary export ATPases are allosterically regulated by the nucleotide second messenger cyclic-di-GMP. J Biol Chem 2015; 290:24470-83. [PMID: 26265469 PMCID: PMC4591828 DOI: 10.1074/jbc.m115.661439] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Indexed: 01/03/2023] Open
Abstract
The widespread second messenger molecule cyclic di-GMP (cdG) regulates the transition from motile and virulent lifestyles to sessile, biofilm-forming ones in a wide range of bacteria. Many pathogenic and commensal bacterial-host interactions are known to be controlled by cdG signaling. Although the biochemistry of cyclic dinucleotide metabolism is well understood, much remains to be discovered about the downstream signaling pathways that induce bacterial responses upon cdG binding. As part of our ongoing research into the role of cdG signaling in plant-associated Pseudomonas species, we carried out an affinity capture screen for cdG binding proteins in the model organism Pseudomonas fluorescens SBW25. The flagella export AAA+ ATPase FliI was identified as a result of this screen and subsequently shown to bind specifically to the cdG molecule, with a KD in the low micromolar range. The interaction between FliI and cdG appears to be very widespread. In addition to FliI homologs from diverse bacterial species, high affinity binding was also observed for the type III secretion system homolog HrcN and the type VI ATPase ClpB2. The addition of cdG was shown to inhibit FliI and HrcN ATPase activity in vitro. Finally, a combination of site-specific mutagenesis, mass spectrometry, and in silico analysis was used to predict that cdG binds to FliI in a pocket of highly conserved residues at the interface between two FliI subunits. Our results suggest a novel, fundamental role for cdG in controlling the function of multiple important bacterial export pathways, through direct allosteric control of export ATPase proteins.
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Affiliation(s)
| | - Clare E M Stevenson
- the Biological Chemistry Department, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | | | - Thomas Wilhelm
- the Institute of Food Research, Norwich Research Park, Norwich NR4 7UA, United Kingdom, and
| | - David M Lawson
- the Biological Chemistry Department, John Innes Centre, Norwich NR4 7UH, United Kingdom
| | - Jacob G Malone
- From the Molecular Microbiology Department and the School of Biological Sciences, University of East Anglia, Norwich NR4 7TJ, United Kingdom
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43
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Muriel C, Jalvo B, Redondo-Nieto M, Rivilla R, Martín M. Chemotactic Motility of Pseudomonas fluorescens F113 under Aerobic and Denitrification Conditions. PLoS One 2015; 10:e0132242. [PMID: 26161531 PMCID: PMC4498747 DOI: 10.1371/journal.pone.0132242] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Accepted: 06/11/2015] [Indexed: 01/01/2023] Open
Abstract
The sequence of the genome of Pseudomonas fluorescens F113 has shown the presence of multiple traits relevant for rhizosphere colonization and plant growth promotion. Among these traits are denitrification and chemotactic motility. Besides aerobic growth, F113 is able to grow anaerobically using nitrate and nitrite as final electron acceptors. F113 is able to perform swimming motility under aerobic conditions and under anaerobic conditions when nitrate is used as the electron acceptor. However, nitrite can not support swimming motility. Regulation of swimming motility is similar under aerobic and anaerobic conditions, since mutants that are hypermotile under aerobic conditions, such as gacS, sadB, kinB, algU and wspR, are also hypermotile under anaerobic conditions. However, chemotactic behavior is different under aerobic and denitrification conditions. Unlike most pseudomonads, the F113 genome encode three complete chemotaxis systems, Che1, Che2 and Che3. Mutations in each of the cheA genes of the three Che systems has shown that the three systems are functional and independent. Mutation of the cheA1 gene completely abolished swimming motility both under aerobic and denitrification conditions. Mutation of the cheA2 gene, showed only a decrease in swimming motility under both conditions, indicating that this system is not essential for chemotactic motility but is necessary for optimal motility. Mutation of the cheA3 gene abolished motility under denitrification conditions but only produced a decrease in motility under aerobic conditions. The three Che systems proved to be implicated in competitive rhizosphere colonization, being the cheA1 mutant the most affected.
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Affiliation(s)
- Candela Muriel
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | - Blanca Jalvo
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | | | - Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
| | - Marta Martín
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Spain
- * E-mail:
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The Xanthomonas oryzae pv. oryzae PilZ Domain Proteins Function Differentially in Cyclic di-GMP Binding and Regulation of Virulence and Motility. Appl Environ Microbiol 2015; 81:4358-67. [PMID: 25911481 DOI: 10.1128/aem.04044-14] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Accepted: 02/10/2015] [Indexed: 12/17/2022] Open
Abstract
The PilZ domain proteins have been demonstrated to be one of the major types of receptors mediating cyclic di-GMP (c-di-GMP) signaling pathways in several pathogenic bacteria. However, little is known about the function of PilZ domain proteins in c-di-GMP regulation of virulence in the bacterial blight pathogen of rice Xanthomonas oryzae pv. oryzae. Here, the roles of PilZ domain proteins PXO_00049 and PXO_02374 in c-di-GMP binding, regulation of virulence and motility, and subcellular localization were characterized in comparison with PXO_02715, identified previously as an interactor with the c-di-GMP receptor Filp to regulate virulence. The c-di-GMP binding motifs in the PilZ domains were conserved in PXO_00049 and PXO_02374 but were less well conserved in PXO_02715. PXO_00049 and PXO_02374 but not PXO_02715 proteins bound to c-di-GMP with high affinity in vitro, and the R(141) and R(10) residues in the PilZ domains of PXO_00049 and PXO_02374, respectively, were crucial for c-di-GMP binding. Gene deletion of PXO_00049 and PXO_02374 resulted in significant increases in virulence and hrp gene transcription, indicating their negative regulation of virulence via type III secretion system expression. All mutants showed significant changes in sliding motility but not exopolysaccharide production and biofilm formation. In trans expression of the full-length open reading frame (ORF) of each gene in the relevant mutants led to restoration of the phenotype to wild-type levels. Moreover, PXO_00049 and PXO_02374 displayed mainly multisite subcellular localizations, whereas PXO_02715 showed nonpolar distributions in the X. oryzae pv. oryzae cells. Therefore, this study demonstrated the different functions of the PilZ domain proteins in mediation of c-di-GMP regulation of virulence and motility in X. oryzae pv. oryzae.
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Cyclic di-GMP-mediated repression of swarming motility by Pseudomonas aeruginosa PA14 requires the MotAB stator. J Bacteriol 2014; 197:420-30. [PMID: 25349157 DOI: 10.1128/jb.02130-14] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The second messenger cyclic diguanylate (c-di-GMP) plays a critical role in the regulation of motility. In Pseudomonas aeruginosa PA14, c-di-GMP inversely controls biofilm formation and surface swarming motility, with high levels of this dinucleotide signal stimulating biofilm formation and repressing swarming. P. aeruginosa encodes two stator complexes, MotAB and MotCD, that participate in the function of its single polar flagellum. Here we show that the repression of swarming motility requires a functional MotAB stator complex. Mutating the motAB genes restores swarming motility to a strain with artificially elevated levels of c-di-GMP as well as stimulates swarming in the wild-type strain, while overexpression of MotA from a plasmid represses swarming motility. Using point mutations in MotA and the FliG rotor protein of the motor supports the conclusion that MotA-FliG interactions are critical for c-di-GMP-mediated swarming inhibition. Finally, we show that high c-di-GMP levels affect the localization of a green fluorescent protein (GFP)-MotD fusion, indicating a mechanism whereby this second messenger has an impact on MotCD function. We propose that when c-di-GMP level is high, the MotAB stator can displace MotCD from the motor, thereby affecting motor function. Our data suggest a newly identified means of c-di-GMP-mediated control of surface motility, perhaps conserved among Pseudomonas, Xanthomonas, and other organisms that encode two stator systems.
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46
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The Pseudomonas aeruginosa diguanylate cyclase GcbA, a homolog of P. fluorescens GcbA, promotes initial attachment to surfaces, but not biofilm formation, via regulation of motility. J Bacteriol 2014; 196:2827-41. [PMID: 24891445 DOI: 10.1128/jb.01628-14] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Cyclic di-GMP is a conserved signaling molecule regulating the transitions between motile and sessile modes of growth in a variety of bacterial species. Recent evidence suggests that Pseudomonas species harbor separate intracellular pools of c-di-GMP to control different phenotypic outputs associated with motility, attachment, and biofilm formation, with multiple diguanylate cyclases (DGCs) playing distinct roles in these processes, yet little is known about the potential conservation of functional DGCs across Pseudomonas species. In the present study, we demonstrate that the P. aeruginosa homolog of the P. fluorescens DGC GcbA involved in promoting biofilm formation via regulation of swimming motility likewise synthesizes c-di-GMP to regulate surface attachment via modulation of motility, however, without affecting subsequent biofilm formation. P. aeruginosa GcbA was found to regulate flagellum-driven motility by suppressing flagellar reversal rates in a manner independent of viscosity, surface hardness, and polysaccharide production. P. fluorescens GcbA was found to be functional in P. aeruginosa and was capable of restoring phenotypes associated with inactivation of gcbA in P. aeruginosa to wild-type levels. Motility and attachment of a gcbA mutant strain could be restored to wild-type levels via overexpression of the small regulatory RNA RsmZ. Furthermore, epistasis analysis revealed that while both contribute to the regulation of initial surface attachment and flagellum-driven motility, GcbA and the phosphodiesterase DipA act within different signaling networks to regulate these processes. Our findings expand the complexity of c-di-GMP signaling in the regulation of the motile-sessile switch by providing yet another potential link to the Gac/Rsm network and suggesting that distinct c-di-GMP-modulating signaling pathways can regulate a single phenotypic output.
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Martínez-Granero F, Redondo-Nieto M, Vesga P, Martín M, Rivilla R. AmrZ is a global transcriptional regulator implicated in iron uptake and environmental adaption in P. fluorescens F113. BMC Genomics 2014; 15:237. [PMID: 24670089 PMCID: PMC3986905 DOI: 10.1186/1471-2164-15-237] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 03/21/2014] [Indexed: 12/04/2022] Open
Abstract
Background AmrZ, a RHH transcriptional regulator, regulates motility and alginate production in pseudomonads. Expression of amrZ depends on the environmental stress sigma factor AlgU. amrZ and algU mutants have been shown to be impaired in environmental fitness in different pseudomonads with different lifestyles. Considering the importance of AmrZ for the ecological fitness of pseudomonads and taking advantage of the full sequencing and annotation of the Pseudomonas fluorescens F113 genome, we have carried out a ChIP-seq analysis from a pool of eight independent ChIP assays in order to determine the AmrZ binding sites and its implication in the regulation of genes involved in environmental adaption. Results 154 enriched regions (AmrZ binding sites) were detected in this analysis, being 76% of them located in putative promoter regions. 18 of these peaks were validated in an independent ChIP assay by qPCR. The 154 peaks were assigned to genes involved in several functional classes such as motility and chemotaxis, iron homeostasis, and signal transduction and transcriptional regulators, including genes encoding proteins implicated in the turn-over of c-diGMP. A putative AmrZ binding site was also observed by aligning the 154 regions with the MEME software. This motif was present in 75% of the peaks and was similar to that described in the amrZ and algD promoters in P. aeruginosa. We have analyzed the role of AmrZ in the regulation of iron uptake genes, to find that AmrZ represses their expression under iron limiting conditions. Conclusions The results presented here show that AmrZ is an important global transcriptional regulator involved in environmental sensing and adaption. It is also a new partner in the complex iron homeostasis regulation.
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Affiliation(s)
| | | | | | | | - Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid, C/Darwin, 2, 28049 Madrid Spain.
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Abstract
Aeromonas species are inhabitants of aquatic environments and are able to cause disease in humans and fish among other animals. In aquaculture, they are responsible for the economically important diseases of furunculosis and motile Aeromonas septicaemia (MAS). Whereas gastroenteritis and wound infections are the major human diseases associated with the genus. As they inhabit and survive in diverse environments, aeromonads possess a wide range of colonisation factors. The motile species are able to swim in liquid environments through the action of a single polar flagellum, the flagellin subunits of which are glycosylated; although essential for function the biological role of glycan addition is yet to be determined. Approximately 60% of aeromonads possess a second lateral flagella system that is expressed in viscous environments for swarming over surfaces; both flagellar systems have been shown to be important in the initial colonisation of surfaces. Subsequently, other non-flagellar colonisation factors are employed; these can be both filamentous and non-filamentous. The aeromonads possess a number of fimbrial systems with the bundle-forming MSHA type IV pilus system, having a major role in human cell adherence. Furthermore, a series of outer-membrane proteins have also been implicated in the aeromonad adhesion process. A number of strains are also capable of cell invasion and that maybe linked with the more invasive diseases of bacteraemia or wound infections. These strains employ cell surface factors that allow the colonisation of these niches that protect them from the host's immune system such as S-layers, capsules or particular lipopolysaccharides.
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Affiliation(s)
- Rebecca Lowry
- Department of Infection and Immunity, University of Sheffield, Sheffield, United Kingdom
| | - Sabela Balboa
- Department of Infection and Immunity, University of Sheffield, Sheffield, United Kingdom; Departamento de Microbiología y Parasitología, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
| | - Jennifer L Parker
- Department of Infection and Immunity, University of Sheffield, Sheffield, United Kingdom
| | - Jonathan G Shaw
- Department of Infection and Immunity, University of Sheffield, Sheffield, United Kingdom.
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