1
|
Fujihara H, Hirose J, Suenaga H. Evolution of genetic architecture and gene regulation in biphenyl/PCB-degrading bacteria. Front Microbiol 2023; 14:1168246. [PMID: 37350784 PMCID: PMC10282184 DOI: 10.3389/fmicb.2023.1168246] [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: 02/17/2023] [Accepted: 05/16/2023] [Indexed: 06/24/2023] Open
Abstract
A variety of bacteria in the environment can utilize xenobiotic compounds as a source of carbon and energy. The bacterial strains degrading xenobiotics are suitable models to investigate the adaptation and evolutionary processes of bacteria because they appear to have emerged relatively soon after the release of these compounds into the natural environment. Analyses of bacterial genome sequences indicate that horizontal gene transfer (HGT) is the most important contributor to the bacterial evolution of genetic architecture. Further, host bacteria that can use energy effectively by controlling the expression of organized gene clusters involved in xenobiotic degradation will have a survival advantage in harsh xenobiotic-rich environments. In this review, we summarize the current understanding of evolutionary mechanisms operative in bacteria, with a focus on biphenyl/PCB-degrading bacteria. We then discuss metagenomic approaches that are useful for such investigation.
Collapse
Affiliation(s)
- Hidehiko Fujihara
- Department of Food and Fermentation Sciences, Faculty of Food and Nutrition Sciences, Beppu University, Beppu, Japan
| | - Jun Hirose
- Department of Applied Chemistry, Faculty of Engineering, University of Miyazaki, Miyazaki, Japan
| | - Hikaru Suenaga
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Tokyo, Japan
| |
Collapse
|
2
|
Hirose J. Diversity and Evolution of Integrative and Conjugative Elements Involved in Bacterial Aromatic Compound Degradation and Their Utility in Environmental Remediation. Microorganisms 2023; 11:microorganisms11020438. [PMID: 36838403 PMCID: PMC9960961 DOI: 10.3390/microorganisms11020438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/12/2023] Open
Abstract
Integrative and conjugative elements (ICEs) are mobile DNA molecules that can be transferred through excision, conjugation, and integration into chromosomes. They contribute to the horizontal transfer of genomic islands across bacterial species. ICEs carrying genes encoding aromatic compound degradation pathways are of interest because of their contribution to environmental remediation. Recent advances in DNA sequencing technology have increased the number of newly discovered ICEs in bacterial genomes and have enabled comparative analysis of their evolution. The two different families of ICEs carry various aromatic compound degradation pathway genes. ICEclc and its related ICEs contain a number of members with diverse catabolic capabilities. In addition, the Tn4371 family, which includes ICEs that carry the chlorinated biphenyl catabolic pathway, has been identified. It is apparent that they underwent evolution through the acquisition, deletion, or exchange of modules to adapt to an environmental niche. ICEs have the property of both stability and mobility in the chromosome. Perspectives on the use of ICEs in environmental remediation are also discussed.
Collapse
Affiliation(s)
- Jun Hirose
- Department of Applied Chemistry, Faculty of Engineering, University of Miyazaki, Miyazaki 889-2192, Japan
| |
Collapse
|
3
|
Mohapatra B, Malhotra H, Phale PS. Life Within a Contaminated Niche: Comparative Genomic Analyses of an Integrative Conjugative Element ICE nahCSV86 and Two Genomic Islands From Pseudomonas bharatica CSV86 T Suggest Probable Role in Colonization and Adaptation. Front Microbiol 2022; 13:928848. [PMID: 35875527 PMCID: PMC9298801 DOI: 10.3389/fmicb.2022.928848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 06/08/2022] [Indexed: 11/26/2022] Open
Abstract
Comparative genomic and functional analyses revealed the presence of three genomic islands (GIs, >50 Kb size): ICEnahCSV86, Pseudomonas bharatica genomic island-1 (PBGI-1), and PBGI-2 in the preferentially aromatic-degrading soil bacterium, Pseudomonas bharatica CSV86T. Site-specific genomic integration at or near specific transfer RNAs (tRNAs), near-syntenic structural modules, and phylogenetic relatedness indicated their evolutionary lineage to the type-4 secretion system (T4SS) ICEclc family, thus predicting these elements to be integrative conjugative elements (ICEs). These GIs were found to be present as a single copy in the genome and the encoded phenotypic traits were found to be stable, even in the absence of selection pressure. ICEnahCSV86 harbors naphthalene catabolic (nah-sal) cluster, while PBGI-1 harbors Co-Zn-Cd (czc) efflux genes as cargo modules, whereas PBGI-2 was attributed to as a mixed-function element. The ICEnahCSV86 has been reported to be conjugatively transferred (frequency of 7 × 10–8/donor cell) to Stenotrophomonas maltophilia CSV89. Genome-wide comparative analyses of aromatic-degrading bacteria revealed nah-sal clusters from several Pseudomonas spp. as part of probable ICEs, syntenic to conjugatively transferable ICEnahCSV86 of strain CSV86T, suggesting it to be a prototypical element for naphthalene degradation. It was observed that the plasmids harboring nah-sal clusters were phylogenetically incongruent with predicted ICEs, suggesting genetic divergence of naphthalene metabolic clusters in the Pseudomonas population. Gene synteny, divergence estimates, and codon-based Z-test indicated that ICEnahCSV86 is probably derived from PBGI-2, while multiple recombination events masked the ancestral lineage of PBGI-1. Diversifying selection pressure (dN-dS = 2.27–4.31) imposed by aromatics and heavy metals implied the modular exchange-fusion of various cargo clusters through events like recombination, rearrangement, domain reshuffling, and active site optimization, thus allowing the strain to evolve, adapt, and maximize the metabolic efficiency in a contaminated niche. The promoters (Pnah and Psal) of naphthalene cargo modules (nah, sal) on ICEnahCSV86 were proved to be efficient for heterologous protein expression in Escherichia coli. GI-based genomic plasticity expands the metabolic spectrum and versatility of CSV86T, rendering efficient adaptation to the contaminated niche. Such isolate(s) are of utmost importance for their application in bioremediation and are the probable ideal host(s) for metabolic engineering.
Collapse
Affiliation(s)
- Balaram Mohapatra
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Harshit Malhotra
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Prashant S Phale
- Department of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Mumbai, India
| |
Collapse
|
4
|
A New ICE clc Subfamily Integrative and Conjugative Element Responsible for Horizontal Transfer of Biphenyl and Salicylic Acid Catabolic Pathway in the PCB-Degrading Strain Pseudomonas stutzeri KF716. Microorganisms 2021; 9:microorganisms9122462. [PMID: 34946064 PMCID: PMC8704644 DOI: 10.3390/microorganisms9122462] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 11/24/2021] [Accepted: 11/25/2021] [Indexed: 11/23/2022] Open
Abstract
Integrative and conjugative elements (ICEs) are chromosomally integrated self-transmissible mobile genetic elements. Although some ICEs are known to carry genes for the degradation of aromatic compounds, information on their genetic features is limited. We identified a new member of the ICEclc family carrying biphenyl catabolic bph genes and salicylic acid catabolic sal genes from the PCB-degrading strain Pseudomonas stutzeri KF716. The 117-kb ICEbph-salKF716 contains common core regions exhibiting homology with those of degradative ICEclc from P. knackmussii B13 and ICEXTD from Azoarcus sp. CIB. A comparison of the gene loci collected from the public database revealed that several putative ICEs from P. putida B6-2, P, alcaliphila JAB1, P. stutzeri AN10, and P. stutzeri 2A20 had highly conserved core regions with those of ICEbph-salKF716, along with the variable region that encodes the catabolic genes for biphenyl, naphthalene, toluene, or phenol. These data indicate that this type of ICE subfamily is ubiquitously distributed within aromatic compound-degrading bacteria. ICEbph-salKF716 was transferred from P. stutzeri KF716 to P. aeruginosa PAO1 via a circular extrachromosomal intermediate form. In this study, we describe the structure and genetic features of ICEbph-salKF716 compared to other catabolic ICEs.
Collapse
|
5
|
Liu Z, Liang Z, Zhou Z, Li L, Meng D, Li X, Tao J, Jiang Z, Gu Y, Huang Y, Liu X, Yang Z, Drewniak L, Liu T, Liu Y, Liu S, Wang J, Jiang C, Yin H. Mobile genetic elements mediate the mixotrophic evolution of novel Alicyclobacillus species for acid mine drainage adaptation. Environ Microbiol 2021; 23:3896-3912. [PMID: 33913568 DOI: 10.1111/1462-2920.15543] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 04/12/2021] [Accepted: 04/24/2021] [Indexed: 12/25/2022]
Abstract
Alicyclobacillus species inhabit diverse environments and have adapted to broad ranges of pH and temperature. However, their adaptive evolutions remain elusive, especially regarding the role of mobile genetic elements (MGEs). Here, we characterized the distributions and functions of MGEs in Alicyclobacillus species across five environments, including acid mine drainage (AMD), beverages, hot springs, sediments, and soils. Nine Alicyclobacillus strains were isolated from AMD and possessed larger genome sizes and more genes than those from other environments. Four AMD strains evolved to be mixotrophic and fell into distinctive clusters in phylogenetic tree. Four types of MGEs including genomic island (GI), insertion sequence (IS), prophage, and integrative and conjugative element (ICE) were widely distributed in Alicyclobacillus species. Further, AMD strains did not possess CRISPR-Cas systems, but had more GI, IS, and ICE, as well as more MGE-associated genes involved in the oxidation of iron and sulfide and the resistance of heavy metal and low temperature. These findings highlight the differences in phenotypes and genotypes between strains isolated from AMD and other environments and the important role of MGEs in rapid environment niche expansions.
Collapse
Affiliation(s)
- Zhenghua Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410006, China.,Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, 410006, China.,State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Zonglin Liang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhicheng Zhou
- College of Plant Protection, Hunan Agricultural University, Changsha, 410010, China
| | - Liangzhi Li
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410006, China.,Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, 410006, China
| | - Delong Meng
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410006, China.,Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, 410006, China
| | - Xiutong Li
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jiemeng Tao
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410006, China.,Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, 410006, China
| | - Zhen Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yabing Gu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410006, China.,Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, 410006, China
| | - Ye Huang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xueduan Liu
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410006, China.,Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, 410006, China
| | - Zhendong Yang
- Department of Environmental Microbiology and Biotechnology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, 02-096, Poland
| | - Lukasz Drewniak
- Department of Environmental Microbiology and Biotechnology, Institute of Microbiology, Faculty of Biology, University of Warsaw, Warsaw, 02-096, Poland
| | - Tianbo Liu
- Hunan Tobacco Science Institute, Changsha, 410010, China
| | - Yongjun Liu
- Hunan Tobacco Science Institute, Changsha, 410010, China
| | - Shuangjiang Liu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100101, China
| | - Jianjun Wang
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Chengying Jiang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China.,University of Chinese Academy of Sciences, Beijing, 100049, China.,Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing, 100101, China
| | - Huaqun Yin
- School of Minerals Processing and Bioengineering, Central South University, Changsha, 410006, China.,Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha, 410006, China
| |
Collapse
|
6
|
Carraro N, Richard X, Sulser S, Delavat F, Mazza C, van der Meer JR. An analog to digital converter controls bistable transfer competence development of a widespread bacterial integrative and conjugative element. eLife 2020; 9:57915. [PMID: 32720896 PMCID: PMC7423338 DOI: 10.7554/elife.57915] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 07/24/2020] [Indexed: 01/08/2023] Open
Abstract
Conjugative transfer of the integrative and conjugative element ICEclc in Pseudomonas requires development of a transfer competence state in stationary phase, which arises only in 3–5% of individual cells. The mechanisms controlling this bistable switch between non-active and transfer competent cells have long remained enigmatic. Using a variety of genetic tools and epistasis experiments in P. putida, we uncovered an ‘upstream’ cascade of three consecutive transcription factor-nodes, which controls transfer competence initiation. One of the uncovered transcription factors (named BisR) is representative for a new regulator family. Initiation activates a feedback loop, controlled by a second hitherto unrecognized heteromeric transcription factor named BisDC. Stochastic modelling and experimental data demonstrated the feedback loop to act as a scalable converter of unimodal (population-wide or ‘analog’) input to bistable (subpopulation-specific or ‘digital’) output. The feedback loop further enables prolonged production of BisDC, which ensures expression of the ‘downstream’ functions mediating ICE transfer competence in activated cells. Phylogenetic analyses showed that the ICEclc regulatory constellation with BisR and BisDC is widespread among Gamma- and Beta-proteobacteria, including various pathogenic strains, highlighting its evolutionary conservation and prime importance to control the behaviour of this wide family of conjugative elements. Mobile DNA elements are pieces of genetic material that can jump from one bacterium to another, and even across species. They are often useful to their host, for example carrying genes that allow bacteria to resist antibiotics. One example of bacterial mobile DNA is the ICEclc element. Usually, ICEclc sits passively within the bacterium’s own DNA, but in a small number of cells, it takes over, hijacking its host to multiply and to get transferred to other bacteria. Cells that can pass on the elements cannot divide, and so this ability is ultimately harmful to individual bacteria. Carrying ICEclc can therefore be positive for a bacterium but passing it on is not in the cell’s best interest. On the other hand, mobile DNAs like ICEclc have evolved to be disseminated as efficiently as possible. To shed more light on this tense relationship, Carraro et al. set out to identify the molecular mechanisms ICEclc deploys to control its host. Experiments using mutant bacteria revealed that for ICEclc to successfully take over the cell, a number of proteins needed to be produced in the correct order. In particular, a protein called BisDC triggers a mechanism to make more of itself, creating a self-reinforcing ‘feedback loop’. Mathematical simulations of the feedback loop showed that it could result in two potential outcomes for the cell. In most of the ‘virtual cells’, ICEclc ultimately remained passive; however, in a few, ICEclc managed to take over its hosts. In this case, the feedback loop ensured that there was always enough BisDC to maintain ICEclc’s control over the cell. Further analyses suggested that this feedback mechanism is also common in many other mobile DNA elements, including some that help bacteria to resist drugs. These results are an important contribution to understand how mobile DNAs manipulate their bacterial host in order to propagate and disperse. In the future, this knowledge could help develop new strategies to combat the spread of antibiotic resistance.
Collapse
Affiliation(s)
- Nicolas Carraro
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - Xavier Richard
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.,Department of Mathematics, University of Fribourg, Fribourg, Switzerland
| | - Sandra Sulser
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland
| | - François Delavat
- Department of Fundamental Microbiology, University of Lausanne, Lausanne, Switzerland.,UMR CNRS 6286 UFIP, University of Nantes, Nantes, France
| | - Christian Mazza
- Department of Mathematics, University of Fribourg, Fribourg, Switzerland
| | | |
Collapse
|
7
|
Phale PS, Shah BA, Malhotra H. Variability in Assembly of Degradation Operons for Naphthalene and its derivative, Carbaryl, Suggests Mobilization through Horizontal Gene Transfer. Genes (Basel) 2019; 10:genes10080569. [PMID: 31357661 PMCID: PMC6723655 DOI: 10.3390/genes10080569] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 07/11/2019] [Accepted: 07/11/2019] [Indexed: 01/14/2023] Open
Abstract
In the biosphere, the largest biological laboratory, increased anthropogenic activities have led microbes to evolve and adapt to the changes occurring in the environment. Compounds, specifically xenobiotics, released due to such activities persist in nature and undergo bio-magnification in the food web. Some of these compounds act as potent endocrine disrupters, mutagens or carcinogens, and therefore their removal from the environment is essential. Due to their persistence, microbial communities have evolved to metabolize them partially or completely. Diverse biochemical pathways have evolved or been assembled by exchange of genetic material (horizontal gene transfer) through various mobile genetic elements like conjugative and non-conjugative plasmids, transposons, phages and prophages, genomic islands and integrative conjugative elements. These elements provide an unlimited opportunity for genetic material to be exchanged across various genera, thus accelerating the evolution of a new xenobiotic degrading phenotype. In this article, we illustrate examples of the assembly of metabolic pathways involved in the degradation of naphthalene and its derivative, Carbaryl, which are speculated to have evolved or adapted through the above-mentioned processes.
Collapse
Affiliation(s)
- Prashant S Phale
- Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Powai, Mumbai-400 076, India.
| | - Bhavik A Shah
- Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Powai, Mumbai-400 076, India
| | - Harshit Malhotra
- Department of Biosciences and Bioengineering, Indian Institute of Technology-Bombay, Powai, Mumbai-400 076, India
| |
Collapse
|
8
|
A Novel Redox-Sensing Histidine Kinase That Controls Carbon Catabolite Repression in Azoarcus sp. CIB. mBio 2019; 10:mBio.00059-19. [PMID: 30967457 PMCID: PMC6456745 DOI: 10.1128/mbio.00059-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have identified and characterized the AccS multidomain sensor kinase that mediates the activation of the AccR master regulator involved in carbon catabolite repression (CCR) of the anaerobic catabolism of aromatic compounds in Azoarcus sp. CIB. A truncated AccS protein that contains only the soluble C-terminal autokinase module (AccS') accounts for the succinate-dependent CCR control. In vitro assays with purified AccS' revealed its autophosphorylation, phosphotransfer from AccS'∼P to the Asp60 residue of AccR, and the phosphatase activity toward its phosphorylated response regulator, indicating that the equilibrium between the kinase and phosphatase activities of AccS' may control the phosphorylation state of the AccR transcriptional regulator. Oxidized quinones, e.g., ubiquinone 0 and menadione, switched the AccS' autokinase activity off, and three conserved Cys residues, which are not essential for catalysis, are involved in such inhibition. Thiol oxidation by quinones caused a change in the oligomeric state of the AccS' dimer resulting in the formation of an inactive monomer. This thiol-based redox switch is tuned by the cellular energy state, which can change depending on the carbon source that the cells are using. This work expands the functional diversity of redox-sensitive sensor kinases, showing that they can control new bacterial processes such as CCR of the anaerobic catabolism of aromatic compounds. The AccSR two-component system is conserved in the genomes of some betaproteobacteria, where it might play a more general role in controlling the global metabolic state according to carbon availability.IMPORTANCE Two-component signal transduction systems comprise a sensor histidine kinase and its cognate response regulator, and some have evolved to sense and convert redox signals into regulatory outputs that allow bacteria to adapt to the altered redox environment. The work presented here expands knowledge of the functional diversity of redox-sensing kinases to control carbon catabolite repression (CCR), a phenomenon that allows the selective assimilation of a preferred compound among a mixture of several carbon sources. The newly characterized AccS sensor kinase is responsible for the phosphorylation and activation of the AccR master regulator involved in CCR of the anaerobic degradation of aromatic compounds in the betaproteobacterium Azoarcus sp. CIB. AccS seems to have a thiol-based redox switch that is modulated by the redox state of the quinone pool. The AccSR system is conserved in several betaproteobacteria, where it might play a more general role controlling their global metabolic state.
Collapse
|
9
|
Suvorova IA, Gelfand MS. Comparative Genomic Analysis of the Regulation of Aromatic Metabolism in Betaproteobacteria. Front Microbiol 2019; 10:642. [PMID: 30984152 PMCID: PMC6449761 DOI: 10.3389/fmicb.2019.00642] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 03/14/2019] [Indexed: 01/23/2023] Open
Abstract
Aromatic compounds are a common carbon and energy source for many microorganisms, some of which can even degrade toxic chloroaromatic xenobiotics. This comparative study of aromatic metabolism in 32 Betaproteobacteria species describes the links between several transcription factors (TFs) that control benzoate (BenR, BenM, BoxR, BzdR), catechol (CatR, CatM, BenM), chlorocatechol (ClcR), methylcatechol (MmlR), 2,4-dichlorophenoxyacetate (TfdR, TfdS), phenol (AphS, AphR, AphT), biphenyl (BphS), and toluene (TbuT) metabolism. We characterize the complexity and variability in the organization of aromatic metabolism operons and the structure of regulatory networks that may differ even between closely related species. Generally, the upper parts of pathways, rare pathway variants, and degradative pathways of exotic and complex, in particular, xenobiotic compounds are often controlled by a single TF, while the regulation of more common and/or central parts of the aromatic metabolism may vary widely and often involves several TFs with shared and/or dual, or cascade regulation. The most frequent and at the same time variable connections exist between AphS, AphR, AphT, and BenR. We have identified a novel LysR-family TF that regulates the metabolism of catechol (or some catechol derivative) and either substitutes CatR(M)/BenM, or shares functions with it. We have also predicted several new members of aromatic metabolism regulons, in particular, some COGs regulated by several different TFs.
Collapse
Affiliation(s)
- Inna A Suvorova
- Institute for Information Transmission Problems RAS (The Kharkevich Institute), Moscow, Russia
| | - Mikhail S Gelfand
- Institute for Information Transmission Problems RAS (The Kharkevich Institute), Moscow, Russia.,Faculty of Computer Science, Higher School of Economics, Moscow, Russia.,Center of Life Sciences, Skolkovo Institute of Science and Technology, Moscow, Russia
| |
Collapse
|
10
|
Obi CC, Vayla S, de Gannes V, Berres ME, Walker J, Pavelec D, Hyman J, Hickey WJ. The Integrative Conjugative Element clc (ICEclc) of Pseudomonas aeruginosa JB2. Front Microbiol 2018; 9:1532. [PMID: 30050515 PMCID: PMC6050381 DOI: 10.3389/fmicb.2018.01532] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Accepted: 06/20/2018] [Indexed: 12/13/2022] Open
Abstract
Integrative conjugative elements (ICE) are a diverse group of chromosomally integrated, self-transmissible mobile genetic elements (MGE) that are active in shaping the functions of bacteria and bacterial communities. Each type of ICE carries a characteristic set of core genes encoding functions essential for maintenance and self-transmission, and cargo genes that endow on hosts phenotypes beneficial for niche adaptation. An important area to which ICE can contribute beneficial functions is the biodegradation of xenobiotic compounds. In the biodegradation realm, the best-characterized ICE is ICEclc, which carries cargo genes encoding for ortho-cleavage of chlorocatechols (clc genes) and aminophenol metabolism (amn genes). The element was originally identified in the 3-chlorobenzoate-degrader Pseudomonas knackmussii B13, and the closest relative is a nearly identical element in Burkholderia xenovorans LB400 (designated ICEclc-B13 and ICEclc-LB400, respectively). In the present report, genome sequencing of the o-chlorobenzoate degrader Pseudomonas aeruginosa JB2 was used to identify a new member of the ICEclc family, ICEclc-JB2. The cargo of ICEclc-JB2 differs from that of ICEclc-B13 and ICEclc-LB400 in consisting of a unique combination of genes that encode for the utilization of o-halobenzoates and o-hydroxybenzoate as growth substrates (ohb genes and hyb genes, respectively) and which are duplicated in a tandem repeat. Also, ICEclc-JB2 lacks an operon of regulatory genes (tciR-marR-mfsR) that is present in the other two ICEclc, and which controls excision from the host. Thus, the mechanisms regulating intracellular behavior of ICEclc-JB2 may differ from that of its close relatives. The entire tandem repeat in ICEclc-JB2 can excise independently from the element in a process apparently involving transposases/insertion sequence associated with the repeats. Excision of the repeats removes important niche adaptation genes from ICEclc-JB2, rendering it less beneficial to the host. However, the reduced version of ICEclc-JB2 could now acquire new genes that might be beneficial to a future host and, consequently, to the survival of ICEclc-JB2. Collectively, the present identification and characterization of ICEclc-JB2 provides insights into roles of MGE in bacterial niche adaptation and the evolution of catabolic pathways for biodegradation of xenobiotic compounds.
Collapse
Affiliation(s)
- Chioma C Obi
- Department of Biological Sciences, Bells University of Technology, Ota, Nigeria
| | - Shivangi Vayla
- Department of Soil Science, University of Wisconsin-Madison, Madison, WI, United States
| | - Vidya de Gannes
- Department of Food Production, University of the West Indies, St. Augustine, Trinidad and Tobago
| | - Mark E Berres
- Biotechnology Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Jason Walker
- Biotechnology Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Derek Pavelec
- Biotechnology Center, University of Wisconsin-Madison, Madison, WI, United States
| | - Joshua Hyman
- Biotechnology Center, University of Wisconsin-Madison, Madison, WI, United States
| | - William J Hickey
- Department of Soil Science, University of Wisconsin-Madison, Madison, WI, United States
| |
Collapse
|
11
|
Blázquez B, Carmona M, Díaz E. Transcriptional Regulation of the Peripheral Pathway for the Anaerobic Catabolism of Toluene and m-Xylene in Azoarcus sp. CIB. Front Microbiol 2018; 9:506. [PMID: 29623071 PMCID: PMC5874301 DOI: 10.3389/fmicb.2018.00506] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 03/06/2018] [Indexed: 11/17/2022] Open
Abstract
Alkylbenzenes, such as toluene and m-xylene, are an important class of contaminant hydrocarbons that are widespread and tend to accumulate in subsurface anoxic environments. The peripheral pathway for the anaerobic oxidation of toluene in bacteria consists of an initial activation catalyzed by a benzylsuccinate synthase (encoded by bss genes), and a subsequent modified β-oxidation of benzylsuccinate to benzoyl-CoA and succinyl-CoA (encoded by bbs genes). We have shown here that the bss and bbs genes, which are located within an integrative and conjugative element, are essential for anaerobic degradation of toluene but also for m-xylene oxidation in the denitrifying beta-proteobacterium Azoarcus sp. CIB. New insights into the transcriptional organization and regulation of a complete gene cluster for anaerobic catabolism of toluene/m-xylene in a single bacterial strain are presented. The bss and bbs genes are transcriptionally coupled into two large convergent catabolic operons driven by the PbssD and PbbsA promoters, respectively, whose expression is inducible when cells grow anaerobically in toluene or m-xylene. An adjacent tdiSR operon driven by the PtdiS promoter encodes a putative two-component regulatory system. TdiR behaves as a transcriptional activator of the PbssD, PbbsA, and PtdiS promoters, being benzylsuccinate/(3-methyl)benzylsuccinate, rather than toluene/m-xylene, the inducers that may trigger the TdiS-mediated activation of TdiR. In addition to the TdiSR-based specific control, the expression of the bss and bbs genes in Azoarcus sp. CIB is under an overimposed regulation that depends on certain environmental factors, such as the presence/absence of oxygen or the availability of preferred carbon sources (catabolite repression). This work paves the way for future strategies toward the reliable assessment of microbial activity in toluene/m-xylene contaminated environments.
Collapse
Affiliation(s)
- Blas Blázquez
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Manuel Carmona
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Madrid, Spain
| | - Eduardo Díaz
- Department of Microbial and Plant Biotechnology, Centro de Investigaciones Biológicas-Consejo Superior de Investigaciones Científicas, Madrid, Spain
| |
Collapse
|
12
|
Zamarro MT, Barragán MJL, Carmona M, García JL, Díaz E. Engineering a bzd cassette for the anaerobic bioconversion of aromatic compounds. Microb Biotechnol 2017; 10:1418-1425. [PMID: 28736925 PMCID: PMC5658619 DOI: 10.1111/1751-7915.12746] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 05/11/2017] [Accepted: 05/11/2017] [Indexed: 01/26/2023] Open
Abstract
Microorganisms able to degrade aromatic contaminants constitute potential valuable biocatalysts to deal with a significant reusable carbon fraction suitable for eco‐efficient valorization processes. Metabolic engineering of anaerobic pathways for degradation and recycling of aromatic compounds is an almost unexplored field. In this work, we present the construction of a functional bzd cassette encoding the benzoyl‐CoA central pathway for the anaerobic degradation of benzoate. The bzd cassette has been used to expand the ability of some denitrifying bacteria to use benzoate as sole carbon source under anaerobic conditions, and it paves the way for future pathway engineering of efficient anaerobic biodegraders of aromatic compounds whose degradation generates benzoyl‐CoA as central intermediate. Moreover, a recombinant Azoarcus sp. CIB strain harbouring the bzd cassette was shown to behave as a valuable biocatalyst for anaerobic toluene valorization towards the synthesis of poly‐3‐hydroxybutyrate (PHB), a biodegradable and biocompatible polyester of increasing biotechnological interest as a sustainable alternative to classical oil‐derived polymers.
Collapse
Affiliation(s)
- María Teresa Zamarro
- Centro de Investigaciones Biológicas, CSIC, C/Ramiro de Maeztu, 9, 28040, Madrid, Spain
| | - María J L Barragán
- Centro de Investigaciones Biológicas, CSIC, C/Ramiro de Maeztu, 9, 28040, Madrid, Spain
| | - Manuel Carmona
- Centro de Investigaciones Biológicas, CSIC, C/Ramiro de Maeztu, 9, 28040, Madrid, Spain
| | - José Luis García
- Centro de Investigaciones Biológicas, CSIC, C/Ramiro de Maeztu, 9, 28040, Madrid, Spain
| | - Eduardo Díaz
- Centro de Investigaciones Biológicas, CSIC, C/Ramiro de Maeztu, 9, 28040, Madrid, Spain
| |
Collapse
|