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McMillan IA, Norris MH, Heacock-Kang Y, Zarzycki-Siek J, Sun Z, Hartney BA, Filipowska LK, Islam MN, Crick DC, Borlee BR, Hoang TT. TetR-like regulator BP1026B_II1561 controls aromatic amino acid biosynthesis and intracellular pathogenesis in Burkholderia pseudomallei. Front Microbiol 2024; 15:1441330. [PMID: 39211319 PMCID: PMC11358695 DOI: 10.3389/fmicb.2024.1441330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 07/29/2024] [Indexed: 09/04/2024] Open
Abstract
Burkholderia pseudomallei (Bp) causes the tropical disease melioidosis that afflicts an estimated 165,000 people each year. Bp is a facultative intracellular pathogen that transits through distinct intracellular stages including attachment to host cells, invasion through the endocytic pathway, escape from the endosome, replication in the cytoplasm, generation of protrusions towards neighboring cells, and host cell fusion allowing Bp infection to spread without exiting the intracellular environment. We have identified a TetR-like transcriptional regulator, BP1026B_II1561, that is up-regulated during the late stages of infection as Bp protrudes toward neighboring cells. We have characterized BP1026B_II1561 and determined that it has a role in pathogenesis. A deletional mutant of BP1026B_II1561 is attenuated in RAW264.7 macrophage and BALB/c mouse models of infection. Using RNA-seq, we found that BP1026B_II1561 controls secondary metabolite biosynthesis, fatty acid degradation, and propanoate metabolism. In addition, we identified that BP1026B_II1561 directly controls expression of an outer membrane porin and genes in the shikimate biosynthetic pathway using ChIP-seq. Transposon mutants of genes within the BP1026B_II1561 regulon show defects during intracellular replication in RAW264.7 cells confirming the role of this transcriptional regulator and the pathways it controls in pathogenesis. BP1026B_II1561 also up-regulates the majority of the enzymes in shikimate and tryptophan biosynthetic pathways, suggesting their importance for Bp physiology. To investigate this, we tested fluorinated analogs of anthranilate and tryptophan, intermediates and products of the shikimate and tryptophan biosynthetic pathways, respectively, and showed inhibition of Bp growth at nanomolar concentrations. The expression of these pathways by BP1026b_II1561 and during intracellular infection combined with the inhibition of Bp growth by fluorotryptophan/anthranilate highlights these pathways as potential targets for therapeutic intervention against melioidosis. In the present study, we have identified BP1026B_II1561 as a critical transcriptional regulator for Bp pathogenesis and partially characterized its role during host cell infection.
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Affiliation(s)
- Ian A. McMillan
- School of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI, United States
| | - Michael H. Norris
- Pathogen Analysis and Translational Health Group, School of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI, United States
| | - Yun Heacock-Kang
- School of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI, United States
| | - Jan Zarzycki-Siek
- School of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI, United States
| | - Zhenxin Sun
- School of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI, United States
| | - Brooke A. Hartney
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Liliana K. Filipowska
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - M. Nurul Islam
- Department of Chemistry, Biochemistry, and Physics, South Dakota State University, Brookings, SD, United States
| | - Dean C. Crick
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Bradley R. Borlee
- Department of Microbiology, Immunology, and Pathology, Colorado State University, Fort Collins, CO, United States
| | - Tung T. Hoang
- School of Life Sciences, University of Hawaiʻi at Mānoa, Honolulu, HI, United States
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2
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Zhou L, Höfte M, Hennessy RC. Does regulation hold the key to optimizing lipopeptide production in Pseudomonas for biotechnology? Front Bioeng Biotechnol 2024; 12:1363183. [PMID: 38476965 PMCID: PMC10928948 DOI: 10.3389/fbioe.2024.1363183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 02/12/2024] [Indexed: 03/14/2024] Open
Abstract
Lipopeptides (LPs) produced by Pseudomonas spp. are specialized metabolites with diverse structures and functions, including powerful biosurfactant and antimicrobial properties. Despite their enormous potential in environmental and industrial biotechnology, low yield and high production cost limit their practical use. While genome mining and functional genomics have identified a multitude of LP biosynthetic gene clusters, the regulatory mechanisms underlying their biosynthesis remain poorly understood. We propose that regulation holds the key to unlocking LP production in Pseudomonas for biotechnology. In this review, we summarize the structure and function of Pseudomonas-derived LPs and describe the molecular basis for their biosynthesis and regulation. We examine the global and specific regulator-driven mechanisms controlling LP synthesis including the influence of environmental signals. Understanding LP regulation is key to modulating production of these valuable compounds, both quantitatively and qualitatively, for industrial and environmental biotechnology.
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Affiliation(s)
- Lu Zhou
- Laboratory of Phytopathology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Monica Höfte
- Laboratory of Phytopathology, Department of Plants and Crops, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Rosanna C. Hennessy
- Department of Plant and Environmental Sciences, University of Copenhagen, Copenhagen, Denmark
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3
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Sani A, Qin WQ, Li JY, Liu YF, Zhou L, Yang SZ, Mu BZ. Structural diversity and applications of lipopeptide biosurfactants as biocontrol agents against phytopathogens: A review. Microbiol Res 2024; 278:127518. [PMID: 37897841 DOI: 10.1016/j.micres.2023.127518] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 10/10/2023] [Accepted: 10/10/2023] [Indexed: 10/30/2023]
Abstract
Amphipathic compounds known as biosurfactants are able to reduce surface and interfacial tensions. These substances produced by microbial organisms perform the same functions as chemical surfactants with several enhancements, the most significant of which is biocontrol activity. Lipopeptide is one of the five biosurfactants from natural resources and is identified as the best alternative for chemical surfactants and the major topic of interest for both scientific and industrial communities due to their increasingly growing potential applications in biological and commercial fields. These are the biological compounds with very less toxicity level that increase their importance in the pesticide industry. In this article we summarize the structural diversity of the microbial lipopeptide biosurfactants and focus on their applications as biocontrol agents in plants, covering (1) an intensive study of the structural diversity of lipopeptide biosurfactants originated primarily by the Bacillus, Pseudomonas, Cyanobacteria, and Actinomycetes species is presented, (2) the comparative study of advantages and disadvantages of characterization techniques and physicochemical properties which have a major role in biocontrol activity of microbial lipopeptides, and (3) their wide range biocontrol applications as systemic resistance inducers against different plant diseases, resistance against phytopathogens by alteration of wettability of plant surfaces and antimicrobial activities of important bioactive lipopeptides produced from Bacillus strains.
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Affiliation(s)
- Asma Sani
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; Engineering Research Center for Microbial Enhanced Oil Recovery, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China
| | - Wan-Qi Qin
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; Engineering Research Center for Microbial Enhanced Oil Recovery, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China
| | - Jia-Yi Li
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; Engineering Research Center for Microbial Enhanced Oil Recovery, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China
| | - Yi-Fan Liu
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai 200237, China; Engineering Research Center for Microbial Enhanced Oil Recovery, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China
| | - Lei Zhou
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai 200237, China; Engineering Research Center for Microbial Enhanced Oil Recovery, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China
| | - Shi-Zhong Yang
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai 200237, China; Engineering Research Center for Microbial Enhanced Oil Recovery, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China
| | - Bo-Zhong Mu
- State Key Laboratory of Bioreactor Engineering and School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai 200237, China; Shanghai Collaborative Innovation Center for Biomanufacturing Technology, East China University of Science and Technology, Shanghai 200237, China; Engineering Research Center for Microbial Enhanced Oil Recovery, Ministry of Education, East China University of Science and Technology, Shanghai 200237, China.
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4
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Calero P, Gurdo N, Nikel PI. Role of the CrcB transporter of Pseudomonas putida in the multi-level stress response elicited by mineral fluoride. Environ Microbiol 2022; 24:5082-5104. [PMID: 35726888 PMCID: PMC9796867 DOI: 10.1111/1462-2920.16110] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/16/2022] [Accepted: 06/19/2022] [Indexed: 01/07/2023]
Abstract
The presence of mineral fluoride (F- ) in the environment has both a geogenic and anthropogenic origin, and the halide has been described to be toxic in virtually all living organisms. While the evidence gathered in different microbial species supports this notion, a systematic exploration of the effects of F- salts on the metabolism and physiology of environmental bacteria remained underexplored thus far. In this work, we studied and characterized tolerance mechanisms deployed by the model soil bacterium Pseudomonas putida KT2440 against NaF. By adopting systems-level omic approaches, including functional genomics and metabolomics, we gauged the impact of this anion at different regulatory levels under conditions that impair bacterial growth. Several genes involved in halide tolerance were isolated in a genome-wide Tn-Seq screening-among which crcB, encoding an F- -specific exporter, was shown to play the predominant role in detoxification. High-resolution metabolomics, combined with the assessment of intracellular and extracellular pH values and quantitative physiology experiments, underscored the key nodes in central carbon metabolism affected by the presence of F- . Taken together, our results indicate that P. putida undergoes a general, multi-level stress response when challenged with NaF that significantly differs from that caused by other saline stressors. While microbial stress responses to saline and oxidative challenges have been extensively studied and described in the literature, very little is known about the impact of fluoride (F- ) on bacterial physiology and metabolism. This state of affairs contrasts with the fact that F- is more abundant than other halides in the Earth crust (e.g. in some soils, the F- concentration can reach up to 1 mg gsoil -1 ). Understanding the global effects of NaF treatment on bacterial physiology is not only relevant to unveil distinct mechanisms of detoxification but it could also guide microbial engineering approaches for the target incorporation of fluorine into value-added organofluorine molecules. In this regard, the soil bacterium P. putida constitutes an ideal model to explore such scenarios, since this species is particularly known for its high level of stress resistance against a variety of physicochemical perturbations.
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Affiliation(s)
- Patricia Calero
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKongens LyngbyDenmark
| | - Nicolás Gurdo
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKongens LyngbyDenmark
| | - Pablo I. Nikel
- The Novo Nordisk Foundation Center for BiosustainabilityTechnical University of DenmarkKongens LyngbyDenmark
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5
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Ferreiro MD, Gallegos MT. Distinctive features of the Gac-Rsm pathway in plant-associated Pseudomonas. Environ Microbiol 2021; 23:5670-5689. [PMID: 33939255 DOI: 10.1111/1462-2920.15558] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/29/2021] [Accepted: 05/01/2021] [Indexed: 02/04/2023]
Abstract
Productive plant-bacteria interactions, either beneficial or pathogenic, require that bacteria successfully sense, integrate and respond to continuously changing environmental and plant stimuli. They use complex signal transduction systems that control a vast array of genes and functions. The Gac-Rsm global regulatory pathway plays a key role in controlling fundamental aspects of the apparently different lifestyles of plant beneficial and phytopathogenic Pseudomonas as it coordinates adaptation and survival while either promoting plant health (biocontrol strains) or causing disease (pathogenic strains). Plant-interacting Pseudomonas stand out for possessing multiple Rsm proteins and Rsm RNAs, but the physiological significance of this redundancy is not yet clear. Strikingly, the components of the Gac-Rsm pathway and the controlled genes/pathways are similar, but the outcome of its regulation may be opposite. Therefore, identifying the target mRNAs bound by the Rsm proteins and their mode of action (repression or activation) is essential to explain the resulting phenotype. Some technical considerations to approach the study of this system are also given. Overall, several important features of the Gac-Rsm cascade are now understood in molecular detail, particularly in Pseudomonas protegens CHA0, but further questions remain to be solved in other plant-interacting Pseudomonas.
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Affiliation(s)
- María-Dolores Ferreiro
- 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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6
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Fungal-Associated Molecules Induce Key Genes Involved in the Biosynthesis of the Antifungal Secondary Metabolites Nunamycin and Nunapeptin in the Biocontrol Strain Pseudomonas fluorescens In5. Appl Environ Microbiol 2020; 86:AEM.01284-20. [PMID: 32826219 DOI: 10.1128/aem.01284-20] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 08/12/2020] [Indexed: 11/20/2022] Open
Abstract
Pseudomonas fluorescens In5 synthesizes the antifungal cyclic lipopeptides (CLPs) nunamycin and nunapeptin, which are similar in structure and genetic organization to the pseudomonas-derived phytotoxins syringomycin and syringopeptin. Regulation of syringomycin and syringopeptin is dependent on the two-component global regulatory system GacS-GacA and the SalA, SyrF, and SyrG transcription factors, which activate syringomycin synthesis in response to plant signal molecules. Previously, we demonstrated that a specific transcription factor, NunF, positively regulates the synthesis of nunamycin and nunapeptin in P. fluorescens In5 and that the nunF gene is upregulated by fungal-associated molecules. This study focused on further unravelling the complex regulation governing CLP synthesis in P. fluorescens In5. Promoter fusions were used to show that the specific activator NunF is dependent on the global regulator of secondary metabolism GacA and is regulated by fungal-associated molecules and low temperatures. In contrast, GacA is stimulated by plant signal molecules leading to the hypothesis that P. fluorescens is a hyphosphere-associated bacterium carrying transcription factor genes that respond to signals indicating the presence of fungi and oomycetes. Based on these findings, we present a model for how synthesis of nunamycin and nunapeptin is regulated by fungal- and oomycete-associated molecules.IMPORTANCE Cyclic lipopeptide (CLP) synthesis gene clusters in pseudomonads display a high degree of synteny, and the structures of the peptides synthesized are very similar. Accordingly, the genomic island encoding the synthesis of syringomycin and syringopeptin in P. syringae pv. syringae closely resembles that of P. fluorescens In5, which contains genes coding for synthesis of the antifungal and anti-oomycete peptides nunamycin and nunapeptin, respectively. However, the regulation of syringomycin and syringopeptin synthesis is different from that of nunamycin and nunapeptin synthesis. While CLP synthesis in the plant pathogen P. syringae pv. syringae is induced by plant signal molecules, such compounds do not significantly influence synthesis of nunamycin and nunapeptin in P. fluorescens In5. Instead, fungal-associated molecules positively regulate antifungal peptide synthesis in P. fluorescens In5, while the synthesis of the global regulator GacA in P. fluorescens In5 is positively regulated by plant signal molecules but not fungal-associated molecules.
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7
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De Vleeschouwer M, Van Kersavond T, Verleysen Y, Sinnaeve D, Coenye T, Martins JC, Madder A. Identification of the Molecular Determinants Involved in Antimicrobial Activity of Pseudodesmin A, a Cyclic Lipopeptide From the Viscosin Group. Front Microbiol 2020; 11:646. [PMID: 32373092 PMCID: PMC7187754 DOI: 10.3389/fmicb.2020.00646] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Accepted: 03/20/2020] [Indexed: 12/24/2022] Open
Abstract
Cyclic lipo(depsi)peptides (CLiPs) from Pseudomonas constitute a class of natural products involved in a broad range of biological functions for their producers. They also display interesting antimicrobial potential including activity against Gram-positive bacteria. Literature has indicated that these compounds can induce membrane permeabilization, possibly through pore-formation, leading to the general view that the cellular membrane constitutes the primary target in their mode of action. In support of this view, we previously demonstrated that the enantiomer of pseudodesmin A, a member of the viscosin group of CLiPs, shows identical activity against a test panel of six Gram-positive bacterial strains. Here, a previously developed total organic synthesis route is used and partly adapted to generate 20 novel pseudodesmin A analogs in an effort to derive links between molecular constitution, structure and activity. From these, the importance of a macrocycle closed by an ester bond as well as a critical length of β-OH fatty acid chain capping the N-terminus is conclusively demonstrated, providing further evidence for the importance of peptide-membrane interactions in the mode of action. Moreover, an alanine scan is used to unearth the contribution of specific amino acid residues to biological activity. Subsequent interpretation in terms of a structural model describing the location and orientation of pseudodesmin A in a membrane environment, allows first insight in the peptide-membrane interactions involved. The biological screening also identified residue positions that appear less sensitive to conservative modifications, allowing the introduction of a non-perturbing tryptophan residue which will pave the way toward biophysical studies using fluorescence spectroscopy.
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Affiliation(s)
- Matthias De Vleeschouwer
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium.,NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Tim Van Kersavond
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium.,NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Yentl Verleysen
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium.,NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Davy Sinnaeve
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Tom Coenye
- Laboratory of Pharmaceutical Microbiology, Department of Pharmaceutical Analysis, Ghent University, Ghent, Belgium
| | - José C Martins
- NMR and Structure Analysis Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
| | - Annemieke Madder
- Organic and Biomimetic Chemistry Research Group, Department of Organic and Macromolecular Chemistry, Ghent University, Ghent, Belgium
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8
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Götze S, Stallforth P. Structure, properties, and biological functions of nonribosomal lipopeptides from pseudomonads. Nat Prod Rep 2020; 37:29-54. [DOI: 10.1039/c9np00022d] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Bacteria of the genusPseudomonasdisplay a fascinating metabolic diversity. In this review, we focus our attention on the natural product class of nonribosomal lipopeptides, which help pseudomonads to colonize a wide range of ecological niches.
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Affiliation(s)
- Sebastian Götze
- Faculty 7: Natural and Environmental Sciences
- Institute for Environmental Sciences
- University Koblenz Landau
- 76829 Landau
- Germany
| | - Pierre Stallforth
- Junior Research Group Chemistry of Microbial Communication
- Leibniz Institute for Natural Product Research and Infection Biology Hans Knöll Institute (HKI)
- 07745 Jena
- Germany
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9
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Geudens N, Kovács B, Sinnaeve D, Oni FE, Höfte M, Martins JC. Conformation and Dynamics of the Cyclic Lipopeptide Viscosinamide at the Water-Lipid Interface. Molecules 2019; 24:E2257. [PMID: 31213011 PMCID: PMC6630293 DOI: 10.3390/molecules24122257] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 06/11/2019] [Accepted: 06/13/2019] [Indexed: 12/19/2022] Open
Abstract
Cyclic lipodepsipeptides or CLiPs from Pseudomonas are secondary metabolites that mediate a wide range of biological functions for their producers, and display antimicrobial and anticancer activities. Direct interaction of CLiPs with the cellular membranes is presumed to be essential in causing these. To understand the processes involved at the molecular level, knowledge of the conformation and dynamics of CLiPs at the water-lipid interface is required to guide the interpretation of biophysical investigations in model membrane systems. We used NMR and molecular dynamics to study the conformation, location and orientation of the Pseudomonas CLiP viscosinamide in a water/dodecylphosphocholine solution. In the process, we demonstrate the strong added value of combining uniform, isotope-enriched viscosinamide and protein NMR methods. In particular, the use of techniques to determine backbone dihedral angles and detect and identify long-lived hydrogen bonds, establishes that the solution conformation previously determined in acetonitrile is maintained in water/dodecylphosphocholine solution. Paramagnetic relaxation enhancements pinpoint viscosinamide near the water-lipid interface, with its orientation dictated by the amphipathic distribution of hydrophobic and hydrophilic residues. Finally, the experimental observations are supported by molecular dynamics simulations. Thus a firm structural basis is now available for interpreting biophysical and bioactivity data relating to this class of compounds.
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Affiliation(s)
- Niels Geudens
- NMR and Structural Analysis Unit, Department of Organic and Macromolecular Chemistry, GhentUniversity, Campus Sterre, S4, Krijgslaan 281, B-9000 Gent, Belgium.
| | - Benjámin Kovács
- NMR and Structural Analysis Unit, Department of Organic and Macromolecular Chemistry, GhentUniversity, Campus Sterre, S4, Krijgslaan 281, B-9000 Gent, Belgium.
| | - Davy Sinnaeve
- NMR and Structural Analysis Unit, Department of Organic and Macromolecular Chemistry, GhentUniversity, Campus Sterre, S4, Krijgslaan 281, B-9000 Gent, Belgium.
| | - Feyisara Eyiwumi Oni
- Laboratory of Phytopathology, Department of Plants and Crops, Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
| | - Monica Höfte
- Laboratory of Phytopathology, Department of Plants and Crops, Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
| | - José C Martins
- NMR and Structural Analysis Unit, Department of Organic and Macromolecular Chemistry, GhentUniversity, Campus Sterre, S4, Krijgslaan 281, B-9000 Gent, Belgium.
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10
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Olorunleke FE, Kieu NP, De Waele E, Timmerman M, Ongena M, Höfte M. Coregulation of the cyclic lipopeptides orfamide and sessilin in the biocontrol strain Pseudomonas sp. CMR12a. Microbiologyopen 2017. [PMID: 28621084 PMCID: PMC5635164 DOI: 10.1002/mbo3.499] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Cyclic lipopeptides (CLPs) are synthesized by nonribosomal peptide synthetases (NRPS), which are often flanked by LuxR‐type transcriptional regulators. Pseudomonas sp. CMR12a, an effective biocontrol strain, produces two different classes of CLPs namely sessilins and orfamides. The orfamide biosynthesis gene cluster is flanked up‐ and downstream by LuxR‐type regulatory genes designated ofaR1 and ofaR2, respectively, whereas the sessilin biosynthesis gene cluster has one LuxR‐type regulatory gene which is situated upstream of the cluster and is designated sesR. Our study investigated the role of these three regulators in the biosynthesis of orfamides and sessilins. Phylogenetic analyses positioned OfaR1 and OfaR2 with LuxR regulatory proteins of similar orfamide‐producing Pseudomonas strains and the SesR with that of the tolaasin producer, Pseudomonas tolaasii. LC‐ESI‐MS analyses revealed that sessilins and orfamides are coproduced and that production starts in the late exponential phase. However, sessilins are secreted earlier and in large amounts, while orfamides are predominantly retained in the cell. Deletion mutants in ofaR1 and ofaR2 lost the capacity to produce both orfamides and sessilins, whereas the sesR mutant showed no clear phenotype. Additionally, RT‐PCR analysis showed that in the sessilin cluster, a mutation in either ofaR1 or ofaR2 led to weaker transcripts of the biosynthesis genes, sesABC, and putative transporter genes, macA1B1. In the orfamide cluster, mainly the biosynthesis genes ofaBC were affected, while the first biosynthesis gene ofaA and putative macA2B2 transport genes were still transcribed. A mutation in either ofaR1, ofaR2, or sesR genes did not abolish the transcription of any of the other two.
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Affiliation(s)
- Feyisara E Olorunleke
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Nam P Kieu
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Evelien De Waele
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Marc Timmerman
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Marc Ongena
- Gembloux Agro-Bio Tech, University of Liège, Gembloux, Belgium
| | - Monica Höfte
- Laboratory of Phytopathology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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11
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Shinde S, Cumming JR, Collart FR, Noirot PH, Larsen PE. Pseudomonas fluorescens Transportome Is Linked to Strain-Specific Plant Growth Promotion in Aspen Seedlings under Nutrient Stress. FRONTIERS IN PLANT SCIENCE 2017; 8:348. [PMID: 28377780 PMCID: PMC5359307 DOI: 10.3389/fpls.2017.00348] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 02/28/2017] [Indexed: 05/21/2023]
Abstract
Diverse communities of bacteria colonize plant roots and the rhizosphere. Many of these rhizobacteria are symbionts and provide plant growth promotion (PGP) services, protecting the plant from biotic and abiotic stresses and increasing plant productivity by providing access to nutrients that would otherwise be unavailable to roots. In return, these symbiotic bacteria receive photosynthetically-derived carbon (C), in the form of sugars and organic acids, from plant root exudates. PGP activities have been characterized for a variety of forest tree species and are important in C cycling and sequestration in terrestrial ecosystems. The molecular mechanisms of these PGP activities, however, are less well-known. In a previous analysis of Pseudomonas genomes, we found that the bacterial transportome, the aggregate activity of a bacteria's transmembrane transporters, was most predictive for the ecological niche of Pseudomonads in the rhizosphere. Here, we used Populus tremuloides Michx. (trembling aspen) seedlings inoculated with one of three Pseudomonas fluorescens strains (Pf0-1, SBW25, and WH6) and one Pseudomonas protegens (Pf-5) as a laboratory model to further investigate the relationships between the predicted transportomic capacity of a bacterial strain and its observed PGP effects in laboratory cultures. Conditions of low nitrogen (N) or low phosphorus (P) availability and the corresponding replete media conditions were investigated. We measured phenotypic and biochemical parameters of P. tremuloides seedlings and correlated P. fluorescens strain-specific transportomic capacities with P. tremuloides seedling phenotype to predict the strain and nutrient environment-specific transporter functions that lead to experimentally observed, strain, and media-specific PGP activities and the capacity to protect plants against nutrient stress. These predicted transportomic functions fall in three groups: (i) transport of compounds that modulate aspen seedling root architecture, (ii) transport of compounds that help to mobilize nutrients for aspen roots, and (iii) transporters that enable bacterial acquisition of C sources from seedling root exudates. These predictions point to specific molecular mechanisms of PGP activities that can be directly tested through future, hypothesis-driven biological experiments.
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Affiliation(s)
- Shalaka Shinde
- Biosciences Division, Argonne National LaboratoryLemont, IL, USA
| | | | - Frank R. Collart
- Biosciences Division, Argonne National LaboratoryLemont, IL, USA
| | | | - Peter E. Larsen
- Biosciences Division, Argonne National LaboratoryLemont, IL, USA
- Department of Bioengineering, University of Illinois at ChicagoChicago, IL, USA
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12
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Geudens N, Nasir MN, Crowet JM, Raaijmakers JM, Fehér K, Coenye T, Martins JC, Lins L, Sinnaeve D, Deleu M. Membrane Interactions of Natural Cyclic Lipodepsipeptides of the Viscosin Group. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:331-339. [DOI: 10.1016/j.bbamem.2016.12.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 12/12/2016] [Accepted: 12/16/2016] [Indexed: 11/16/2022]
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13
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Liu Y, Rzeszutek E, van der Voort M, Wu CH, Thoen E, Skaar I, Bulone V, Dorrestein PC, Raaijmakers JM, de Bruijn I. Diversity of Aquatic Pseudomonas Species and Their Activity against the Fish Pathogenic Oomycete Saprolegnia. PLoS One 2015; 10:e0136241. [PMID: 26317985 PMCID: PMC4552890 DOI: 10.1371/journal.pone.0136241] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 07/30/2015] [Indexed: 12/20/2022] Open
Abstract
Emerging fungal and oomycete pathogens are increasingly threatening animals and plants globally. Amongst oomycetes, Saprolegnia species adversely affect wild and cultivated populations of amphibians and fish, leading to substantial reductions in biodiversity and food productivity. With the ban of several chemical control measures, new sustainable methods are needed to mitigate Saprolegnia infections in aquaculture. Here, PhyloChip-based community analyses showed that the Pseudomonadales, particularly Pseudomonas species, represent one of the largest bacterial orders associated with salmon eggs from a commercial hatchery. Among the Pseudomonas species isolated from salmon eggs, significantly more biosurfactant producers were retrieved from healthy salmon eggs than from Saprolegnia-infected eggs. Subsequent in vivo activity bioassays showed that Pseudomonas isolate H6 significantly reduced salmon egg mortality caused by Saprolegnia diclina. Live colony mass spectrometry showed that strain H6 produces a viscosin-like lipopeptide surfactant. This biosurfactant inhibited growth of Saprolegnia in vitro, but no significant protection of salmon eggs against Saprolegniosis was observed. These results indicate that live inocula of aquatic Pseudomonas strains, instead of their bioactive compound, can provide new (micro)biological and sustainable means to mitigate oomycete diseases in aquaculture.
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Affiliation(s)
- Yiying Liu
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
| | - Elzbieta Rzeszutek
- Division of Glycoscience, School of Biotechnology, Royal Institute of Technology, Stockholm, Sweden
| | - Menno van der Voort
- Laboratory of Phytopathology, Wageningen University, Wageningen, The Netherlands
| | - Cheng-Hsuan Wu
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, United States of America
- Department of Chemistry, Boston University, Boston, United States of America
| | - Even Thoen
- Norwegian Veterinary Institute, Oslo, Norway
- Norwegian University of Life Sciences, Oslo, Norway
| | - Ida Skaar
- Norwegian Veterinary Institute, Oslo, Norway
| | - Vincent Bulone
- Division of Glycoscience, School of Biotechnology, Royal Institute of Technology, Stockholm, Sweden
| | - Pieter C. Dorrestein
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, United States of America
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, United States of America
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California, United States of America
- Department of Pharmacology, University of California San Diego, La Jolla, California, United States of America
| | - Jos M. Raaijmakers
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
| | - Irene de Bruijn
- Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Wageningen, The Netherlands
- * E-mail:
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14
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Zachow C, Jahanshah G, de Bruijn I, Song C, Ianni F, Pataj Z, Gerhardt H, Pianet I, Lämmerhofer M, Berg G, Gross H, Raaijmakers JM. The Novel Lipopeptide Poaeamide of the Endophyte Pseudomonas poae RE*1-1-14 Is Involved in Pathogen Suppression and Root Colonization. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2015; 28:800-10. [PMID: 25761208 DOI: 10.1094/mpmi-12-14-0406-r] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Endophytic Pseudomonas poae strain RE*1-1-14 was originally isolated from internal root tissue of sugar beet plants and shown to suppress growth of the fungal pathogen Rhizoctonia solani both in vitro and in the field. To identify genes involved in its biocontrol activity, RE*1-1-14 random mutagenesis and sequencing led to the identification of a nonribosomal peptide synthetase (NRPS) gene cluster predicted to encode a lipopeptide (LP) with a 10-amino-acid peptide moiety. The two unlinked gene clusters consisted of three NRPS genes, designated poaA (cluster 1) and poaB and poaC (cluster 2), spanning approximately 33.7 kb. In silico analysis followed by chemical analyses revealed that the encoded LP, designated poaeamide, is a structurally new member of the orfamide family. Poaeamide inhibited mycelial growth of R. solani and different oomycetes, including Phytophthora capsici, P. infestans, and Pythium ultimum. The novel LP was shown to be essential for swarming motility of strain RE*1-1-14 and had an impact on root colonization of sugar beet seedlings The poaeamide-deficient mutant colonized the rhizosphere and upper plant cortex at higher densities and with more scattered colonization patterns than the wild type. Collectively, these results indicate that Pseudomonas poae RE*1-1-14 produces a structurally new LP that is relevant for its antagonistic activity against soilborne plant pathogens and for colonization of sugar beet roots.
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Affiliation(s)
- Christin Zachow
- 1 Austrian Centre of Industrial Biotechnology (ACIB GmbH), 8010 Graz, Austria
| | - Ghazaleh Jahanshah
- 2 Pharmaceutical Institute, Department of Pharmaceutical Biology, University of Tübingen, 72076 Tübingen, Germany
| | - Irene de Bruijn
- 3 Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Chunxu Song
- 3 Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
| | - Federica Ianni
- 4 Pharmaceutical Institute, Department of Pharmaceutical Analysis and Bioanalysis, University of Tübingen
| | - Zoltán Pataj
- 4 Pharmaceutical Institute, Department of Pharmaceutical Analysis and Bioanalysis, University of Tübingen
| | - Heike Gerhardt
- 4 Pharmaceutical Institute, Department of Pharmaceutical Analysis and Bioanalysis, University of Tübingen
| | - Isabelle Pianet
- 5 CESAMO-ISM, UMR 5255, CNRS, Université Bordeaux I, 351 Cours de la Libération, F-33405 Talence, France
| | - Michael Lämmerhofer
- 4 Pharmaceutical Institute, Department of Pharmaceutical Analysis and Bioanalysis, University of Tübingen
| | - Gabriele Berg
- 6 Institute of Environmental Biotechnology, Graz University of Technology, 8010 Graz, Austria
| | - Harald Gross
- 2 Pharmaceutical Institute, Department of Pharmaceutical Biology, University of Tübingen, 72076 Tübingen, Germany
| | - Jos M Raaijmakers
- 3 Department of Microbial Ecology, Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, The Netherlands
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15
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Patel S, Ahmed S, Eswari JS. Therapeutic cyclic lipopeptides mining from microbes: latest strides and hurdles. World J Microbiol Biotechnol 2015; 31:1177-93. [PMID: 26041368 DOI: 10.1007/s11274-015-1880-8] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2015] [Accepted: 05/31/2015] [Indexed: 12/23/2022]
Abstract
Infectious diseases impose serious public health burdens and often have devastating consequences. The cyclic lipopeptides elaborated by bacteria Bacillus, Paenibacillus, Pseudomonas, Streptomyces, Serratia, Propionibacterium and fungus Fusarium are very crucial in restraining the pathogens. Composed of a peptide and a fatty acyl moiety these amphiphilic metabolites exhibit broad spectrum antimicrobial effects. Among the plethora of cyclic lipopeptides, only selective few have emerged as robust antibiotics. For their functional vigor, polymyxin, daptomycin, surfactin, iturin, fengysin, paenibacterin and pseudofactin have been integrated in mainstream healthcare. Daptomycin has been a significant part of antimicrobial arsenal since the past decade. As the magnitude of drug resistance rises in unprecedented manner, the urgency of prospecting novel cyclic lipopeptides is being perceived. Intense research has revealed the implication of these bioactive compounds stretching beyond antibacterial and antifungal. Anticancer, immunomodulatory, prosthetic parts disinfection and vaccine adjuvancy are some of the validated prospects. This review discusses the emerging applications, mechanisms governing the biological actions, role of genomics in refining structure and function, semi-synthetic analog discovery, novel strain isolation, setbacks etc. Though its beyond the scope of the current topic, for holistic purpose, the role of lipopeptides in bioremediation and crop biotechnology has been briefly outlined. This updated critique is expected to galvanize innovations and diversify therapeutic recruitment of microbial lipopeptides.
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Affiliation(s)
- Seema Patel
- Bioinformatics and Medical Informatics Research Center, San Diego State University, San Diego, CA, 92182, USA,
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16
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Rumbaugh KP. Genomic complexity and plasticity ensure Pseudomonas success. FEMS Microbiol Lett 2015; 356:141-3. [PMID: 25060810 DOI: 10.1111/1574-6968.12517] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Affiliation(s)
- Kendra P Rumbaugh
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, TX, USA.
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17
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Song C, Sundqvist G, Malm E, de Bruijn I, Kumar A, van de Mortel J, Bulone V, Raaijmakers JM. Lipopeptide biosynthesis in Pseudomonas fluorescens is regulated by the protease complex ClpAP. BMC Microbiol 2015; 15:29. [PMID: 25885431 PMCID: PMC4332742 DOI: 10.1186/s12866-015-0367-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Accepted: 01/29/2015] [Indexed: 11/10/2022] Open
Abstract
Background Lipopeptides (LP) are structurally diverse compounds with potent surfactant and broad-spectrum antibiotic activities. In Pseudomonas and other bacterial genera, LP biosynthesis is governed by large multimodular nonribosomal peptide synthetases (NRPS). To date, relatively little is known about the regulatory genetic network of LP biosynthesis. Results This study provides evidence that the chaperone ClpA, together with the serine protease ClpP, regulates the biosynthesis of the LP massetolide in Pseudomonas fluorescens SS101. Whole-genome transcriptome analyses of clpA and clpP mutants showed their involvement in the transcription of the NRPS genes massABC and the transcriptional regulator massAR. In addition, transcription of genes associated with cell wall and membrane biogenesis, energy production and conversion, amino acid transport and metabolism, and pilus assembly were altered by mutations in clpA and clpP. Proteome analysis allowed the identification of additional cellular changes associated to clpA and clpP mutations. The expression of proteins of the citrate cycle and the heat shock proteins DnaK and DnaJ were particularly affected. Combined with previous findings, these results suggest that the ClpAP complex regulates massetolide biosynthesis via the pathway-specific, LuxR-type regulator MassAR, the heat shock proteins DnaK and DnaJ, and proteins of the TCA cycle. Conclusions Combining transcriptome and proteome analyses provided new insights into the regulation of LP biosynthesis in P. fluorescens and led to the identification of specific missing links in the regulatory pathways. Electronic supplementary material The online version of this article (doi:10.1186/s12866-015-0367-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chunxu Song
- Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, the Netherlands. .,Department of Microbial Ecology, Netherlands Institute of Ecology, Droevendaalsesteeg 10, 6708 PB, Wageningen, the Netherlands.
| | - Gustav Sundqvist
- Division of Glycoscience, Royal Institute of Technology (KTH), AlbaNova University Centre, SE-106 91, Stockholm, Sweden.
| | - Erik Malm
- Division of Glycoscience, Royal Institute of Technology (KTH), AlbaNova University Centre, SE-106 91, Stockholm, Sweden.
| | - Irene de Bruijn
- Department of Microbial Ecology, Netherlands Institute of Ecology, Droevendaalsesteeg 10, 6708 PB, Wageningen, the Netherlands.
| | - Aundy Kumar
- Division of Plant Pathology, Indian Agricultural Research Institute, New Delhi, 110012, India.
| | - Judith van de Mortel
- Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, the Netherlands. .,Current address: HAS University of Applied Sciences, 5911 KJ, Venlo, the Netherlands.
| | - Vincent Bulone
- Division of Glycoscience, Royal Institute of Technology (KTH), AlbaNova University Centre, SE-106 91, Stockholm, Sweden.
| | - Jos M Raaijmakers
- Laboratory of Phytopathology, Wageningen University, 6708 PB, Wageningen, the Netherlands. .,Department of Microbial Ecology, Netherlands Institute of Ecology, Droevendaalsesteeg 10, 6708 PB, Wageningen, the Netherlands.
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18
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Okrent RA, Halgren AB, Azevedo MD, Chang JH, Mills DI, Maselko M, Armstrong DJ, Banowetz GM, Trippe KM. Negative regulation of germination-arrest factor production in Pseudomonas fluorescens WH6 by a putative extracytoplasmic function sigma factor. Microbiology (Reading) 2014; 160:2432-2442. [DOI: 10.1099/mic.0.080317-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Pseudomonas fluorescens WH6 secretes a germination-arrest factor (GAF) that we have identified previously as 4-formylaminooxyvinylglycine. GAF irreversibly inhibits germination of the seeds of numerous grassy weeds and selectively inhibits growth of the bacterial plant pathogen Erwinia amylovora. WH6-3, a mutant that has lost the ability to produce GAF, contains a Tn5 insertion in prtR, a gene that has been described previously in some strains of P. fluorescens as encoding a transmembrane regulator. As in these other pseudomonads, in WH6, prtR occurs immediately downstream of prtI, which encodes a protein homologous to extracytoplasmic function (ECF) sigma factors. These two genes have been proposed to function as a dicistronic operon. In this study, we demonstrated that deletion of prtI in WT WH6 had no effect on GAF production. However, deletion of prtI in the WH6-3 mutant overcame the effects of the Tn5 insertion in prtR and restored GAF production in the resulting double mutant. Complementation of the double prtIR mutant with prtI suppressed GAF production. This overall pattern of prtIR regulation was also observed for the activity of an AprX protease. Furthermore, reverse transcription quantitative real-time PCR analysis demonstrated that alterations in GAF production were mirrored by changes in the transcription of two putative GAF biosynthetic genes. Thus, we concluded that PrtI exerted a negative regulatory effect on GAF production, although the mechanism has not yet been determined. In addition, evidence was obtained that the transcription of prtI and prtR in WH6 may be more complex than predicted by existing models.
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Affiliation(s)
- Rachel A. Okrent
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Anne B. Halgren
- USDA-ARS National Forage Seed Production Research Center, Corvallis, OR 97331, USA
| | - Mark D. Azevedo
- USDA-ARS National Forage Seed Production Research Center, Corvallis, OR 97331, USA
| | - Jeff H. Chang
- Center for Genome Research and Biocomputing, Oregon State University, Corvallis, OR 97331, USA
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Dallice I. Mills
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Maciej Maselko
- USDA-ARS National Forage Seed Production Research Center, Corvallis, OR 97331, USA
| | - Donald J. Armstrong
- Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA
| | - Gary M. Banowetz
- USDA-ARS National Forage Seed Production Research Center, Corvallis, OR 97331, USA
| | - Kristin M. Trippe
- USDA-ARS National Forage Seed Production Research Center, Corvallis, OR 97331, USA
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