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Zhang SN, Li HM, Liu Q, Li XZ, Yang WD, Zhou Y. Omics combined with network pharmacology reveal the neuroprotective mechanism of Sophora tonkinensis based on the biolabel research pattern: The treatment of Parkinson's disease against oxidative stress and neuroexcitatory toxicity. Biomed Chromatogr 2023; 37:e5557. [PMID: 36453605 DOI: 10.1002/bmc.5557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 11/19/2022] [Accepted: 11/26/2022] [Indexed: 12/04/2022]
Abstract
Based on the biolabel research pattern, omics and network pharmacology were used for exploring the neuroprotection of Sophora tonkinensis (ST) in the treatment of brain diseases. Multi-omics were applied to investigate biolabels for ST intervention in brain tissue. Based on biolabels, the therapeutic potential, mechanism and material basis of ST for treating brain diseases were topologically analyzed by network pharmacology. A Parkinson's disease (PD) mouse model was used to validate biolabel analysis results. Four proteins and three metabolites were involved in two key pathways (alanine, aspartate and glutamate metabolism and arginine biosynthesis) and considered as biolabels. Network pharmacology showed that ST has the potential to treat some brain diseases, especially PD. Eight compounds (including caffeic acid, gallic acid and cinnamic acid) may serve as the material basis of ST treating brain diseases via the mediation of three biolabels. In the PD model, ST and its active compounds (caffeic acid and gallic acid) may protect dopaminergic neurons (maximum recovery rate for dopamine, 49.5%) from oxidative stress (E3 ubiquitin-protein ligase parkin, reactive oxygen species, nitric oxide, etc.) and neuroexcitatory toxicity (glutamate dehydrogenase, glutamine, glutamic acid, etc.). These findings indicated that omics and network pharmacology may contribute to the achievement of the objectives of this study based on the biolabel research pattern.
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Affiliation(s)
- Shuai-Nan Zhang
- College of Pharmacy, Guizhou University of Traditional Chinese Medicine, China
| | - Hong-Mei Li
- College of Pharmacy, Guizhou University of Traditional Chinese Medicine, China
| | - Qi Liu
- The Research Institute of Medicine and Pharmacy, Qiqihar Medical University, Qiqihar, China
| | - Xu-Zhao Li
- College of Pharmacy, Guizhou University of Traditional Chinese Medicine, China
| | - Wu-de Yang
- College of Pharmacy, Guizhou University of Traditional Chinese Medicine, China
| | - Ying Zhou
- College of Pharmacy, Guizhou University of Traditional Chinese Medicine, China
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2
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Chen K, Xu X, Yang M, Liu T, Liu B, Zhu J, Wang B, Jiang J. Genetic redundancy of 4-hydroxybenzoate 3-hydroxylase genes ensures the catabolic safety of Pigmentiphaga sp. H8 in 3-bromo-4-hydroxybenzoate-contaminated habitats. Environ Microbiol 2022; 24:5123-5138. [PMID: 35876302 DOI: 10.1111/1462-2920.16141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 07/17/2022] [Accepted: 07/17/2022] [Indexed: 11/28/2022]
Abstract
Genetic redundancy is prevalent in organisms and plays important roles in the evolution of biodiversity and adaptation to environmental perturbation. However, selective advantages of genetic redundancy in overcoming metabolic disturbance due to structural analogues have received little attention. Here, functional divergence of the three 4-hydroxybenzoate 3-hydroxylase (PHBH) genes (phbh1~3) was found in Pigmentiphaga sp. strain H8. The genes phbh1/phbh2 were responsible for 3-bromo-4-hydroxybenzoate (3-Br-4-HB, an anthropogenic pollutant) catabolism, whereas phbh3 was primarily responsible for 4-hydroxybenzoate (4-HB, a natural intermediate of lignin) catabolism. 3-Br-4-HB inhibited 4-HB catabolism by competitively binding PHBH3, and was toxic to strain H8 cells especially at high concentrations. The existence of phbh1/phbh2 not only enabled strain H8 to utilize 3-Br-4-HB, but also ensured the catabolic safety of 4-HB. Molecular docking and site-directed mutagenesis analyses revealed that Val199 and Phe384 of PHBH1/PHBH2 were required for the hydroxylation activity towards 3-Br-4-HB. Phylogenetic analysis indicated that phbh1 and phbh2 originated from a common ancestor and evolved specifically in strain H8 to adapt to 3-Br-4-HB-contaminated habitats, whereas phbh3 evolved independently. This study deepens our understanding of selective advantages of genetic redundancy in prokaryote's metabolic robustness and reveals the factors driving the divergent evolution of redundant genes in adaptation to environmental perturbation. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Kai Chen
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Xihui Xu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Muji Yang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Tairong Liu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Bin Liu
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Jianchun Zhu
- Laboratory Centre of Life Sciences, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Baozhan Wang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
| | - Jiandong Jiang
- Department of Microbiology, College of Life Sciences, Nanjing Agricultural University, Key Laboratory of Agricultural and Environmental Microbiology, Ministry of Agriculture and Rural Affairs, Nanjing, China
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3
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Abstract
Naturally occurring plasmids come in different sizes. The smallest are less than a kilobase of DNA, while the largest can be over three orders of magnitude larger. Historically, research has tended to focus on smaller plasmids that are usually easier to isolate, manipulate and sequence, but with improved genome assemblies made possible by long-read sequencing, there is increased appreciation that very large plasmids—known as megaplasmids—are widespread, diverse, complex, and often encode key traits in the biology of their host microorganisms. Why are megaplasmids so big? What other features come with large plasmid size that could affect bacterial ecology and evolution? Are megaplasmids 'just' big plasmids, or do they have distinct characteristics? In this perspective, we reflect on the distribution, diversity, biology, and gene content of megaplasmids, providing an overview to these large, yet often overlooked, mobile genetic elements. This article is part of the theme issue ‘The secret lives of microbial mobile genetic elements’.
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Affiliation(s)
- James P J Hall
- Department of Evolution, Ecology and Behaviour, Institute of Infection, Veterinary and Ecological Sciences, University of Liverpool, Liverpool, UK
| | - João Botelho
- Antibiotic Resistance Evolution Group, Max Planck Institute for Evolutionary Biology, Plön, Germany.,Department of Evolutionary Ecology and Genetics, Zoological Institute, Christian Albrechts University, Kiel, Germany
| | - Adrian Cazares
- EMBL's European Bioinformatics Institute (EMBL-EBI), Wellcome Genome Campus, Cambridge, UK.,Wellcome Sanger Institute, Wellcome Genome Campus, Cambridge, UK
| | - David A Baltrus
- School of Plant Sciences, University of Arizona, Tucson, AZ, USA
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4
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Galán-Vásquez E, Perez-Rueda E. Identification of Modules With Similar Gene Regulation and Metabolic Functions Based on Co-expression Data. Front Mol Biosci 2019; 6:139. [PMID: 31921888 PMCID: PMC6929668 DOI: 10.3389/fmolb.2019.00139] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Accepted: 11/18/2019] [Indexed: 12/16/2022] Open
Abstract
Biological systems respond to environmental perturbations and to a large diversity of compounds through gene interactions, and these genetic factors comprise complex networks. In particular, a wide variety of gene co-expression networks have been constructed in recent years thanks to the dramatic increase of experimental information obtained with techniques, such as microarrays and RNA sequencing. These networks allow the identification of groups of co-expressed genes that can function in the same process and, in turn, these networks may be related to biological functions of industrial, medical and academic interest. In this study, gene co-expression networks for 17 bacterial organisms from the COLOMBOS database were analyzed via weighted gene co-expression network analysis and clustered into modules of genes with similar expression patterns for each species. These networks were analyzed to determine relevant modules through a hypergeometric approach based on a set of transcription factors and enzymes for each genome. The richest modules were characterized using PFAM families and KEGG metabolic maps. Additionally, we conducted a Gene Ontology analysis for enrichment of biological functions. Finally, we identified modules that shared similarity through all the studied organisms by using comparative genomics.
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Affiliation(s)
- Edgardo Galán-Vásquez
- Departamento de Ingeniería de Sistemas Computacionales y Automatización, Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Ciudad Universitaria, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Ernesto Perez-Rueda
- Instituto de Investigaciones en Matemáticas Aplicadas y en Sistemas, Universidad Nacional Autónoma de México, Unidad Académica Yucatán, Mérida, Mexico.,Centro de Genómica y Bioinformática, Facultad de Ciencias, Universidad Mayor, Santiago, Chile
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5
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Zoledowska S, Presta L, Fondi M, Decorosi F, Giovannetti L, Mengoni A, Lojkowska E. Metabolic Modeling of Pectobacterium parmentieri SCC3193 Provides Insights into Metabolic Pathways of Plant Pathogenic Bacteria. Microorganisms 2019; 7:E101. [PMID: 30959803 PMCID: PMC6518042 DOI: 10.3390/microorganisms7040101] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Revised: 03/26/2019] [Accepted: 04/02/2019] [Indexed: 12/17/2022] Open
Abstract
Understanding plant⁻microbe interactions is crucial for improving plants' productivity and protection. Constraint-based metabolic modeling is one of the possible ways to investigate the bacterial adaptation to different ecological niches and may give insights into the metabolic versatility of plant pathogenic bacteria. We reconstructed a raw metabolic model of the emerging plant pathogenic bacterium Pectobacterium parmentieri SCC3193 with the use of KBase. The model was curated by using inParanoind and phenotypic data generated with the use of the OmniLog system. Metabolic modeling was performed through COBRApy Toolbox v. 0.10.1. The curated metabolic model of P. parmentieri SCC3193 is highly reliable, as in silico obtained results overlapped up to 91% with experimental data on carbon utilization phenotypes. By mean of flux balance analysis (FBA), we predicted the metabolic adaptation of P. parmentieri SCC3193 to two different ecological niches, relevant for the persistence and plant colonization by this bacterium: soil and the rhizosphere. We performed in silico gene deletions to predict the set of essential core genes for this bacterium to grow in such environments. We anticipate that our metabolic model will be a valuable element for defining a set of metabolic targets to control infection and spreading of this plant pathogen.
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Affiliation(s)
- Sabina Zoledowska
- Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, 58 Abrahama Street, 80-307 Gdansk, Poland.
| | - Luana Presta
- Department of Biology, University of Florence, via Madonna del Piano 6, Sesto Fiorentino, 50019 Florence, Italy.
| | - Marco Fondi
- Department of Biology, University of Florence, via Madonna del Piano 6, Sesto Fiorentino, 50019 Florence, Italy.
| | - Francesca Decorosi
- Department of Agri-food Production and Environmental Sciences, University of Florence, Piazzale delle Cascine 18, 50144 Florence, Italy.
| | - Luciana Giovannetti
- Department of Agri-food Production and Environmental Sciences, University of Florence, Piazzale delle Cascine 18, 50144 Florence, Italy.
| | - Alessio Mengoni
- Department of Biology, University of Florence, via Madonna del Piano 6, Sesto Fiorentino, 50019 Florence, Italy.
| | - Ewa Lojkowska
- Department of Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, 58 Abrahama Street, 80-307 Gdansk, Poland.
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6
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diCenzo GC, Mengoni A, Fondi M. Tn-Core: A Toolbox for Integrating Tn-seq Gene Essentiality Data and Constraint-Based Metabolic Modeling. ACS Synth Biol 2019; 8:158-169. [PMID: 30525460 DOI: 10.1021/acssynbio.8b00432] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The design of synthetic cells requires a detailed understanding of the relevance of genes and gene networks underlying complex cellular phenotypes. Transposon-sequencing (Tn-seq) and constraint-based metabolic modeling can be used to probe the core genetic and metabolic networks underlying a biological process. Integrating these highly complementary experimental and in silico approaches has the potential to yield a highly comprehensive understanding of the core networks of a cell. Specifically, it can facilitate the interpretation of Tn-seq data sets and identify gaps in the data that could hinder the engineering of the cellular system, while also providing refined models for the accurate predictions of cellular metabolism. Here, we present Tn-Core, the first easy-to-use computational pipeline specifically designed for integrating Tn-seq data with metabolic modeling, prepared for use by both experimental and computational biologists. Tn-Core is a MATLAB toolbox that contains several custom functions, and it is built upon existing functions within the COBRA Toolbox and the TIGER Toolbox. Tn-Core takes as input a genome-scale metabolic model, Tn-seq data, and optionally RNA-seq data, and returns: (i) a context-specific core metabolic model; (ii) an evaluation of redundancies within core metabolic pathways, and optionally (iii) a refined genome-scale metabolic model. A simple, user-friendly workflow, requiring limited knowledge of metabolic modeling, is provided that allows users to run the analyses and export the data as easy-to-explore files of value to both experimental and computational biologists. We demonstrate the utility of Tn-Core using Sinorhizobium meliloti, Pseudomonas aeruginosa, and Rhodobacter sphaeroides genome-scale metabolic reconstructions as case studies.
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Affiliation(s)
- George C. diCenzo
- Department of Biology, University of Florence, Sesto Fiorentino, Florence, 50019, Italy
| | - Alessio Mengoni
- Department of Biology, University of Florence, Sesto Fiorentino, Florence, 50019, Italy
| | - Marco Fondi
- Department of Biology, University of Florence, Sesto Fiorentino, Florence, 50019, Italy
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7
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Yang ZK, Luo H, Zhang Y, Wang B, Gao F. Pan-genomic analysis provides novel insights into the association of E.coli with human host and its minimal genome. Bioinformatics 2018; 35:1987-1991. [DOI: 10.1093/bioinformatics/bty938] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Revised: 11/06/2018] [Accepted: 11/08/2018] [Indexed: 11/13/2022] Open
Affiliation(s)
- Zhi-Kai Yang
- Department of Physics, School of Science
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
- SinoGenoMax Co., Ltd./Chinese National Human Genome Center, Beijing, China
| | - Hao Luo
- Department of Physics, School of Science
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
| | - Yanming Zhang
- SinoGenoMax Co., Ltd./Chinese National Human Genome Center, Beijing, China
| | - Baijing Wang
- SinoGenoMax Co., Ltd./Chinese National Human Genome Center, Beijing, China
| | - Feng Gao
- Department of Physics, School of Science
- Key Laboratory of Systems Bioengineering (Ministry of Education), Tianjin University, Tianjin, China
- SynBio Research Platform, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Tianjin, China
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8
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Checcucci A, diCenzo GC, Ghini V, Bazzicalupo M, Becker A, Decorosi F, Döhlemann J, Fagorzi C, Finan TM, Fondi M, Luchinat C, Turano P, Vignolini T, Viti C, Mengoni A. Creation and Characterization of a Genomically Hybrid Strain in the Nitrogen-Fixing Symbiotic Bacterium Sinorhizobium meliloti. ACS Synth Biol 2018; 7:2365-2378. [PMID: 30223644 DOI: 10.1021/acssynbio.8b00158] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Many bacteria, often associated with eukaryotic hosts and of relevance for biotechnological applications, harbor a multipartite genome composed of more than one replicon. Biotechnologically relevant phenotypes are often encoded by genes residing on the secondary replicons. A synthetic biology approach to developing enhanced strains for biotechnological purposes could therefore involve merging pieces or entire replicons from multiple strains into a single genome. Here we report the creation of a genomic hybrid strain in a model multipartite genome species, the plant-symbiotic bacterium Sinorhizobium meliloti. We term this strain as cis-hybrid, since it is produced by genomic material coming from the same species' pangenome. In particular, we moved the secondary replicon pSymA (accounting for nearly 20% of total genome content) from a donor S. meliloti strain to an acceptor strain. The cis-hybrid strain was screened for a panel of complex phenotypes (carbon/nitrogen utilization phenotypes, intra- and extracellular metabolomes, symbiosis, and various microbiological tests). Additionally, metabolic network reconstruction and constraint-based modeling were employed for in silico prediction of metabolic flux reorganization. Phenotypes of the cis-hybrid strain were in good agreement with those of both parental strains. Interestingly, the symbiotic phenotype showed a marked cultivar-specific improvement with the cis-hybrid strains compared to both parental strains. These results provide a proof-of-principle for the feasibility of genome-wide replicon-based remodelling of bacterial strains for improved biotechnological applications in precision agriculture.
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Affiliation(s)
- Alice Checcucci
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - George C. diCenzo
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Veronica Ghini
- CERM & CIRMMP, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Marco Bazzicalupo
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Anke Becker
- LOEWE − Center for Synthetic Microbiology, 35043 Marburg, Germany
| | - Francesca Decorosi
- Department of Agri-food Production and Environmental Science, University of Florence, 50019 Florence, Italy
| | | | - Camilla Fagorzi
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Turlough M. Finan
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Marco Fondi
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Claudio Luchinat
- CERM & CIRMMP, University of Florence, 50019 Sesto Fiorentino, Italy
- CERM and Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Paola Turano
- CERM & CIRMMP, University of Florence, 50019 Sesto Fiorentino, Italy
- CERM and Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Tiziano Vignolini
- European Laboratory for Non-Linear Spectroscopy, LENS, 50019 Sesto Fiorentino, Italy
| | - Carlo Viti
- Department of Agri-food Production and Environmental Science, University of Florence, 50019 Florence, Italy
| | - Alessio Mengoni
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
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9
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Fournes F, Val ME, Skovgaard O, Mazel D. Replicate Once Per Cell Cycle: Replication Control of Secondary Chromosomes. Front Microbiol 2018; 9:1833. [PMID: 30131796 PMCID: PMC6090056 DOI: 10.3389/fmicb.2018.01833] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2018] [Accepted: 07/23/2018] [Indexed: 12/13/2022] Open
Abstract
Faithful vertical transmission of genetic information, especially of essential core genes, is a prerequisite for bacterial survival. Hence, replication of all the replicons is tightly controlled to ensure that all daughter cells get the same genome copy as their mother cell. Essential core genes are very often carried by the main chromosome. However they can occasionally be found on secondary chromosomes, recently renamed chromids. Chromids have evolved from non-essential megaplasmids, and further acquired essential core genes and a genomic signature closed to that of the main chromosome. All chromids carry a plasmidic replication origin, belonging so far to either the iterons or repABC type. Based on these differences, two categories of chromids have been distinguished. In this review, we focus on the replication initiation controls of these two types of chromids. We show that the sophisticated mechanisms controlling their replication evolved from their plasmid counterparts to allow a timely controlled replication, occurring once per cell cycle.
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Affiliation(s)
- Florian Fournes
- Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Institut Pasteur, Paris, France.,UMR3525, Centre National de la Recherche Scientifique, Paris, France
| | - Marie-Eve Val
- Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Institut Pasteur, Paris, France.,UMR3525, Centre National de la Recherche Scientifique, Paris, France
| | - Ole Skovgaard
- Department of Science and Environment, Roskilde University, Roskilde, Denmark
| | - Didier Mazel
- Unité Plasticité du Génome Bactérien, Département Génomes et Génétique, Institut Pasteur, Paris, France.,UMR3525, Centre National de la Recherche Scientifique, Paris, France
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10
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Brambilla S, Frare R, Soto G, Jozefkowicz C, Ayub N. Absence of the Nitrous Oxide Reductase Gene Cluster in Commercial Alfalfa Inoculants Is Probably Due to the Extensive Loss of Genes During Rhizobial Domestication. MICROBIAL ECOLOGY 2018; 76:299-302. [PMID: 29330647 DOI: 10.1007/s00248-018-1145-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 01/02/2018] [Indexed: 06/07/2023]
Abstract
As other legume crops, alfalfa cultivation increases the emission of the greenhouse gas nitrous oxide (N2O). Since legume-symbiotic nitrogen-fixing bacteria play a crucial role in this emission, it is important to understand the possible impacts of rhizobial domestication on the evolution of denitrification genes. In comparison with the genomes of non-commercial strains, those of commercial alfalfa inoculants exhibit low total genome size, low number of ORFs and high numbers of both frameshifted genes and pseudogenes, suggesting a dramatic loss of genes during bacterial domestication. Genomic analysis focused on denitrification genes revealed that commercial strains have perfectly conserved the nitrate (NAP), nitrite (NIR) and nitric (NOR) reductase clusters related to the production of N2O from nitrate but completely lost the nitrous oxide (NOS) reductase cluster (nosRZDFYLX genes) associated with the reduction of N2O to gas nitrogen. Based on these results, we propose future screenings for alfalfa-nodulating isolates containing both nitrogen fixation and N2O reductase genes for environmental sustainability of alfalfa production.
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Affiliation(s)
- Silvina Brambilla
- Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, C25(1712), Castelar, Buenos Aires, Argentina
| | - Romina Frare
- Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, C25(1712), Castelar, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina
| | - Gabriela Soto
- Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, C25(1712), Castelar, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina
| | - Cintia Jozefkowicz
- Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, C25(1712), Castelar, Buenos Aires, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina
| | - Nicolás Ayub
- Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, C25(1712), Castelar, Buenos Aires, Argentina.
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina.
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11
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Inter-replicon Gene Flow Contributes to Transcriptional Integration in the Sinorhizobium meliloti Multipartite Genome. G3-GENES GENOMES GENETICS 2018; 8:1711-1720. [PMID: 29563186 PMCID: PMC5940162 DOI: 10.1534/g3.117.300405] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Integration of newly acquired genes into existing regulatory networks is necessary for successful horizontal gene transfer (HGT). Ten percent of bacterial species contain at least two DNA replicons over 300 kilobases in size, with the secondary replicons derived predominately through HGT. The Sinorhizobium meliloti genome is split between a 3.7 Mb chromosome, a 1.7 Mb chromid consisting largely of genes acquired through ancient HGT, and a 1.4 Mb megaplasmid consisting primarily of recently acquired genes. Here, RNA-sequencing is used to examine the transcriptional consequences of massive, synthetic genome reduction produced through the removal of the megaplasmid and/or the chromid. Removal of the pSymA megaplasmid influenced the transcription of only six genes. In contrast, removal of the chromid influenced expression of ∼8% of chromosomal genes and ∼4% of megaplasmid genes. This was mediated in part by the loss of the ETR DNA region whose presence on pSymB is due to a translocation from the chromosome. No obvious functional bias among the up-regulated genes was detected, although genes with putative homologs on the chromid were enriched. Down-regulated genes were enriched in motility and sensory transduction pathways. Four transcripts were examined further, and in each case the transcriptional change could be traced to loss of specific pSymB regions. In particularly, a chromosomal transporter was induced due to deletion of bdhA likely mediated through 3-hydroxybutyrate accumulation. These data provide new insights into the evolution of the multipartite bacterial genome, and more generally into the integration of horizontally acquired genes into the transcriptome.
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12
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diCenzo GC, Benedict AB, Fondi M, Walker GC, Finan TM, Mengoni A, Griffitts JS. Robustness encoded across essential and accessory replicons of the ecologically versatile bacterium Sinorhizobium meliloti. PLoS Genet 2018; 14:e1007357. [PMID: 29672509 PMCID: PMC5929573 DOI: 10.1371/journal.pgen.1007357] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2018] [Revised: 05/01/2018] [Accepted: 04/10/2018] [Indexed: 11/19/2022] Open
Abstract
Bacterial genome evolution is characterized by gains, losses, and rearrangements of functional genetic segments. The extent to which large-scale genomic alterations influence genotype-phenotype relationships has not been investigated in a high-throughput manner. In the symbiotic soil bacterium Sinorhizobium meliloti, the genome is composed of a chromosome and two large extrachromosomal replicons (pSymA and pSymB, which together constitute 45% of the genome). Massively parallel transposon insertion sequencing (Tn-seq) was employed to evaluate the contributions of chromosomal genes to growth fitness in both the presence and absence of these extrachromosomal replicons. Ten percent of chromosomal genes from diverse functional categories are shown to genetically interact with pSymA and pSymB. These results demonstrate the pervasive robustness provided by the extrachromosomal replicons, which is further supported by constraint-based metabolic modeling. A comprehensive picture of core S. meliloti metabolism was generated through a Tn-seq-guided in silico metabolic network reconstruction, producing a core network encompassing 726 genes. This integrated approach facilitated functional assignments for previously uncharacterized genes, while also revealing that Tn-seq alone missed over a quarter of wild-type metabolism. This work highlights the many functional dependencies and epistatic relationships that may arise between bacterial replicons and across a genome, while also demonstrating how Tn-seq and metabolic modeling can be used together to yield insights not obtainable by either method alone. S. meliloti, which has traditionally facilitated ground-breaking insights into symbiotic communication, is also emerging as an excellent model for studying the evolution of functional relationships between bacterial chromosomes and anciently acquired accessory replicons. Multi-replicon genome architecture is present in ~ 10% of presently sequenced bacterial genomes. The S. meliloti genome is composed of three circular replicons, two of which are dispensable even though they encompass nearly half of the protein-coding genes in this organism. The construction of strains lacking these replicons has enabled a straightforward, genome-wide analysis of interactions between the chromosome and the non-essential replicons, revealing extensive functional cooperation between these genomic components. This analysis enabled a substantial refinement of a metabolic network model for S. meliloti. The integration of massively parallel genotype-phenotype screening with in silico metabolic reconstruction has enhanced our understanding of metabolic network structure as it relates to genome evolution in S. meliloti, and exemplifies an approach that may be productively applied to other taxa. The combined experimental and computational approach employed here further provides unique insights into the pervasive genetic interactions that may exist within large bacterial genomes.
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Affiliation(s)
- George C. diCenzo
- Department of Biology, University of Florence, Sesto Fiorentino, FI, Italy
- * E-mail:
| | - Alex B. Benedict
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, United States of America
| | - Marco Fondi
- Department of Biology, University of Florence, Sesto Fiorentino, FI, Italy
| | - Graham C. Walker
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
| | | | - Alessio Mengoni
- Department of Biology, University of Florence, Sesto Fiorentino, FI, Italy
| | - Joel S. Griffitts
- Department of Microbiology and Molecular Biology, Brigham Young University, Provo, UT, United States of America
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13
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diCenzo GC, Finan TM. Techniques for Large-Scale Bacterial Genome Manipulation and Characterization of the Mutants with Respect to In Silico Metabolic Reconstructions. Methods Mol Biol 2018; 1716:291-314. [PMID: 29222759 DOI: 10.1007/978-1-4939-7528-0_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The rate at which all genes within a bacterial genome can be identified far exceeds the ability to characterize these genes. To assist in associating genes with cellular functions, a large-scale bacterial genome deletion approach can be employed to rapidly screen tens to thousands of genes for desired phenotypes. Here, we provide a detailed protocol for the generation of deletions of large segments of bacterial genomes that relies on the activity of a site-specific recombinase. In this procedure, two recombinase recognition target sequences are introduced into known positions of a bacterial genome through single cross-over plasmid integration. Subsequent expression of the site-specific recombinase mediates recombination between the two target sequences, resulting in the excision of the intervening region and its loss from the genome. We further illustrate how this deletion system can be readily adapted to function as a large-scale in vivo cloning procedure, in which the region excised from the genome is captured as a replicative plasmid. We next provide a procedure for the metabolic analysis of bacterial large-scale genome deletion mutants using the Biolog Phenotype MicroArray™ system. Finally, a pipeline is described, and a sample Matlab script is provided, for the integration of the obtained data with a draft metabolic reconstruction for the refinement of the reactions and gene-protein-reaction relationships in a metabolic reconstruction.
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Affiliation(s)
- George C diCenzo
- Department of Biology, McMaster University, Hamilton, ON, Canada
| | - Turlough M Finan
- Department of Biology, McMaster University, Hamilton, ON, Canada.
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14
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Checcucci A, DiCenzo GC, Bazzicalupo M, Mengoni A. Trade, Diplomacy, and Warfare: The Quest for Elite Rhizobia Inoculant Strains. Front Microbiol 2017; 8:2207. [PMID: 29170661 PMCID: PMC5684177 DOI: 10.3389/fmicb.2017.02207] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/26/2017] [Indexed: 01/12/2023] Open
Abstract
Rhizobia form symbiotic nitrogen-fixing nodules on leguminous plants, which provides an important source of fixed nitrogen input into the soil ecosystem. The improvement of symbiotic nitrogen fixation is one of the main challenges facing agriculture research. Doing so will reduce the usage of chemical nitrogen fertilizer, contributing to the development of sustainable agriculture practices to deal with the increasing global human population. Sociomicrobiological studies of rhizobia have become a model for the study of the evolution of mutualistic interactions. The exploitation of the wide range of social interactions rhizobia establish among themselves, with the soil and root microbiota, and with the host plant, could constitute a great advantage in the development of a new generation of highly effective rhizobia inoculants. Here, we provide a brief overview of the current knowledge on three main aspects of rhizobia interaction: trade of fixed nitrogen with the plant; diplomacy in terms of communication and possible synergistic effects; and warfare, as antagonism and plant control over symbiosis. Then, we propose new areas of investigation and the selection of strains based on the combination of the genetic determinants for the relevant rhizobia symbiotic behavioral phenotypes.
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Affiliation(s)
- Alice Checcucci
- Department of Biology, University of Florence, Florence, Italy
| | | | | | - Alessio Mengoni
- Department of Biology, University of Florence, Florence, Italy
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15
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Jozefkowicz C, Brambilla S, Frare R, Stritzler M, Piccinetti C, Puente M, Berini CA, Pérez PR, Soto G, Ayub N. Stable symbiotic nitrogen fixation under water-deficit field conditions by a stress-tolerant alfalfa microsymbiont and its complete genome sequence. J Biotechnol 2017; 263:52-54. [PMID: 29050878 DOI: 10.1016/j.jbiotec.2017.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Revised: 09/19/2017] [Accepted: 10/11/2017] [Indexed: 11/25/2022]
Abstract
We here characterized the stress-tolerant alfalfa microsymbiont Sinorhizobium meliloti B401. B401-treated plants showed high nitrogen fixation rates under humid and semiarid environments. The production of glycine betaine in isolated bacteroids positively correlated with low precipitation levels, suggesting that this compound acts as a critical osmoprotectant under field conditions. Genome analysis revealed that strain B401 contains alternative pathways for the biosynthesis and uptake of glycine betaine and its precursors. Such genomic information will offer substantial insight into the environmental physiology of this biotechnologically valuable nitrogen-fixing bacterium.
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Affiliation(s)
- Cintia Jozefkowicz
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina; Instituto de Genética Ewald A. Favret (INTA), Buenos Aires, Argentina
| | - Silvina Brambilla
- Instituto de Genética Ewald A. Favret (INTA), Buenos Aires, Argentina
| | - Romina Frare
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina; Instituto de Genética Ewald A. Favret (INTA), Buenos Aires, Argentina
| | - Margarita Stritzler
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina; Instituto de Genética Ewald A. Favret (INTA), Buenos Aires, Argentina
| | - Carlos Piccinetti
- Instituto de Microbiología y Zoología Agrícola (INTA), Buenos Aires, Argentina
| | - Mariana Puente
- Instituto de Microbiología y Zoología Agrícola (INTA), Buenos Aires, Argentina
| | | | - Pedro Reyes Pérez
- Instituto de Genética Ewald A. Favret (INTA), Buenos Aires, Argentina
| | - Gabriela Soto
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina; Instituto de Genética Ewald A. Favret (INTA), Buenos Aires, Argentina
| | - Nicolás Ayub
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Argentina; Instituto de Genética Ewald A. Favret (INTA), Buenos Aires, Argentina.
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16
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Friedrich M. Ancient genetic redundancy of eyeless and twin of eyeless in the arthropod ocular segment. Dev Biol 2017; 432:192-200. [PMID: 28993201 DOI: 10.1016/j.ydbio.2017.10.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2017] [Revised: 10/02/2017] [Accepted: 10/03/2017] [Indexed: 01/28/2023]
Abstract
Pax6 transcription factors are essential upstream regulators in the developing anterior brain and peripheral visual system of most bilaterian animals. While a single homolog is in charge of these functions in vertebrates, two Pax6 genes are in Drosophila: eyeless (ey) and twin of eyeless (toy). At first glance, their co-existence seems sufficiently explained by their differential involvement in the specification of two types of insect visual organs: the lateral compound eyes (ey) and the dorsal ocelli (toy). Less straightforward to understand, however, is their genetic redundancy in promoting defined early and late growth phases of the precursor tissue to these organs: the eye-antennal imaginal disc. Drawing on comparative sequence, expression, and gene function evidence, I here conclude that this gene regulatory network module dates back to the dawn of arthropod evolution, securing the embryonic development of the ocular head segment. Thus, ey and toy constitute a paradigm to explore the organization and functional significance of longterm conserved genetic redundancy of duplicated genes. Indeed, as first steps in this direction, recent studies uncovered the shared use of binding sites in shared enhancers of target genes that are under redundant (string) and, strikingly, even subfunctionalized control by ey and toy (atonal). Equally significant, the evolutionarily recent and paralog-specific function of ey to repress the transcription of the antenna fate regulator Distal-less offers a functionally and phylogenetically well-defined opportunity to study the reconciliation of shared, partitioned, and newly acquired functions in a duplicated developmental gene pair.
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Affiliation(s)
- Markus Friedrich
- Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Detroit, MI 48202, USA; Department of Anatomy and Cell Biology, Wayne State University, School of Medicine, 540 East Canfield Avenue, Detroit, MI 48201,USA.
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17
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diCenzo GC, Finan TM. The Divided Bacterial Genome: Structure, Function, and Evolution. Microbiol Mol Biol Rev 2017; 81:e00019-17. [PMID: 28794225 PMCID: PMC5584315 DOI: 10.1128/mmbr.00019-17] [Citation(s) in RCA: 135] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Approximately 10% of bacterial genomes are split between two or more large DNA fragments, a genome architecture referred to as a multipartite genome. This multipartite organization is found in many important organisms, including plant symbionts, such as the nitrogen-fixing rhizobia, and plant, animal, and human pathogens, including the genera Brucella, Vibrio, and Burkholderia. The availability of many complete bacterial genome sequences means that we can now examine on a broad scale the characteristics of the different types of DNA molecules in a genome. Recent work has begun to shed light on the unique properties of each class of replicon, the unique functional role of chromosomal and nonchromosomal DNA molecules, and how the exploitation of novel niches may have driven the evolution of the multipartite genome. The aims of this review are to (i) outline the literature regarding bacterial genomes that are divided into multiple fragments, (ii) provide a meta-analysis of completed bacterial genomes from 1,708 species as a way of reviewing the abundant information present in these genome sequences, and (iii) provide an encompassing model to explain the evolution and function of the multipartite genome structure. This review covers, among other topics, salient genome terminology; mechanisms of multipartite genome formation; the phylogenetic distribution of multipartite genomes; how each part of a genome differs with respect to genomic signatures, genetic variability, and gene functional annotation; how each DNA molecule may interact; as well as the costs and benefits of this genome structure.
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Affiliation(s)
- George C diCenzo
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
| | - Turlough M Finan
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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18
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PhoU Allows Rapid Adaptation to High Phosphate Concentrations by Modulating PstSCAB Transport Rate in Sinorhizobium meliloti. J Bacteriol 2017; 199:JB.00143-17. [PMID: 28416708 DOI: 10.1128/jb.00143-17] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 04/11/2017] [Indexed: 01/14/2023] Open
Abstract
Maintenance of cellular phosphate homeostasis is essential for cellular life. The PhoU protein has emerged as a key regulator of this process in bacteria, and it is suggested to modulate phosphate import by PstSCAB and control activation of the phosphate limitation response by the PhoR-PhoB two-component system. However, a proper understanding of PhoU has remained elusive due to numerous complications of mutating phoU, including loss of viability and the genetic instability of the mutants. Here, we developed two sets of strains of Sinorhizobium meliloti that overcame these limitations and allowed a more detailed and comprehensive analysis of the biological and molecular activities of PhoU. The data showed that phoU cannot be deleted in the presence of phosphate unless PstSCAB is inactivated also. However, phoU deletions were readily recovered in phosphate-free media, and characterization of these mutants revealed that addition of phosphate to the environment resulted in toxic levels of PstSCAB-mediated phosphate accumulation. Phosphate uptake experiments indicated that PhoU significantly decreased the PstSCAB transport rate specifically in phosphate-replete cells but not in phosphate-starved cells and that PhoU could rapidly respond to elevated environmental phosphate concentrations and decrease the PstSCAB transport rate. Site-directed mutagenesis results suggested that the ability of PhoU to respond to phosphate levels was independent of the conformation of the PstSCAB transporter. Additionally, PhoU-PhoU and PhoU-PhoR interactions were detected using a bacterial two-hybrid screen. We propose that PhoU modulates PstSCAB and PhoR-PhoB in response to local, internal fluctuations in phosphate concentrations resulting from PstSCAB-mediated phosphate import.IMPORTANCE Correct maintenance of cellular phosphate homeostasis is critical in all kingdoms of life and in bacteria involves the PhoU protein. This work provides novel insights into the role of the Sinorhizobium meliloti PhoU protein, which plays a key role in rapid adaptation to elevated phosphate concentrations. It is shown that PhoU rapidly responds to elevated phosphate levels by significantly decreasing the phosphate transport of PstSCAB, thereby preventing phosphate toxicity and cell death. Additionally, a new model for phosphate sensing in bacterial species which involves the PhoR-PhoB two-component system is presented. This work provides new insights into the bacterial response to changing environmental conditions and into regulation of the phosphate limitation response that influences numerous bacterial processes, including antibiotic production and virulence.
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19
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Jozefkowicz C, Brambilla S, Frare R, Stritzler M, Puente M, Piccinetti C, Soto G, Ayub N. Microevolution Rather than Large Genome Divergence Determines the Effectiveness of Legume-Rhizobia Symbiotic Interaction Under Field Conditions. J Mol Evol 2017; 85:79-83. [PMID: 28828631 DOI: 10.1007/s00239-017-9808-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2017] [Accepted: 08/12/2017] [Indexed: 11/24/2022]
Abstract
Despite the vast screening for natural nitrogen-fixing isolates by public and private consortia, no significant progresses in the production of improved nitrogen-fixing inoculants for alfalfa production have been made in the last years. Here, we present a comprehensive characterization of the nitrogen-fixing strain Ensifer meliloti B399 (originally named Rhizobium meliloti 102F34), probably the inoculant most widely used in alfalfa production since the 1960s. Complete nucleotide sequence and genome analysis of strain B399 showed that the three replicons present in this commercial strain and the model bacterium Ensifer meliloti 1021 are extremely similar to each other in terms of nucleotide identity and synteny conservation. In contrast to that observed in B399-treated plants, inoculation of plants with strain 1021 did not improve nitrogen content in different alfalfa cultivars under field conditions, suggesting that a small genomic divergence can drastically impact on the symbiotic phenotype. Therefore, in addition to the traditional screening of natural nitrogen-fixing isolates, the genome engineering of model strains could be an attractive strategy to improve nitrogen fixation in legume crops.
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Affiliation(s)
- Cintia Jozefkowicz
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, Castelar C25(1712), Buenos Aires, Argentina
| | - Silvina Brambilla
- Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, Castelar C25(1712), Buenos Aires, Argentina
| | - Romina Frare
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, Castelar C25(1712), Buenos Aires, Argentina
| | - Margarita Stritzler
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, Castelar C25(1712), Buenos Aires, Argentina
| | - Mariana Puente
- Instituto de Microbiología y Zoología Agrícola (INTA), Buenos Aires, Argentina
| | - Carlos Piccinetti
- Instituto de Microbiología y Zoología Agrícola (INTA), Buenos Aires, Argentina
| | - Gabriela Soto
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Buenos Aires, Argentina.,Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, Castelar C25(1712), Buenos Aires, Argentina
| | - Nicolás Ayub
- Consejo Nacional de Investigaciones Científicas y Técnicas, CABA, Buenos Aires, Argentina. .,Instituto de Genética Ewald A. Favret (INTA), De los Reseros S/N, Castelar C25(1712), Buenos Aires, Argentina.
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20
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diCenzo GC, Zamani M, Ludwig HN, Finan TM. Heterologous Complementation Reveals a Specialized Activity for BacA in the Medicago-Sinorhizobium meliloti Symbiosis. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2017; 30:312-324. [PMID: 28398123 DOI: 10.1094/mpmi-02-17-0030-r] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The bacterium Sinorhizobium meliloti Rm2011 forms N2-fixing root nodules on alfalfa and other leguminous plants. The pSymB chromid contains a 110-kb region (the ETR region) showing high synteny to a chromosomally located region in Sinorhizobium fredii NGR234 and related rhizobia. We recently introduced the ETR region from S. fredii NGR234 into the S. meliloti chromosome. Here, we report that, unexpectedly, the S. fredii NGR234 ETR region did not complement deletion of the S. meliloti ETR region in symbiosis with Medicago sativa. This phenotype was due to the bacA gene of NGR234 not being functionally interchangeable with the S. meliloti bacA gene during M. sativa symbiosis. Further analysis revealed that, whereas bacA genes from S. fredii or Rhizobium leguminosarum bv. viciae 3841 failed to complement the Fix- phenotype of a S. meliloti bacA mutant with M. sativa, they allowed for further developmental progression prior to a loss of viability. In contrast, with Melilotus alba, bacA from S. fredii and R. leguminosarum supported N2 fixation by a S. meliloti bacA mutant. Additionally, the S. meliloti bacA gene can support N2 fixation of a R. leguminosarum bacA mutant during symbiosis with Pisum sativum. A phylogeny of BacA proteins illustrated that S. meliloti BacA has rapidly diverged from most rhizobia and has converged toward the sequence of pathogenic genera Brucella and Escherichia. These data suggest that the S. meliloti BacA has evolved toward a specific interaction with Medicago and highlights the limitations of using a single model system for the study of complex biological topics.
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Affiliation(s)
- George C diCenzo
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4K1, Canada
| | - Maryam Zamani
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4K1, Canada
| | - Hannah N Ludwig
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4K1, Canada
| | - Turlough M Finan
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4K1, Canada
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21
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Zamani M, diCenzo GC, Milunovic B, Finan TM. A putative 3-hydroxyisobutyryl-CoA hydrolase is required for efficient symbiotic nitrogen fixation in Sinorhizobium meliloti and Sinorhizobium fredii NGR234. Environ Microbiol 2016; 19:218-236. [PMID: 27727485 DOI: 10.1111/1462-2920.13570] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 10/06/2016] [Indexed: 12/12/2022]
Abstract
We report that the smb20752 gene of the alfalfa symbiont Sinorhizobium meliloti is a novel symbiotic gene required for full N2 -fixation. Deletion of smb20752 resulted in lower nitrogenase activity and smaller nodules without impacting overall nodule morphology. Orthologs of smb20752 were present in all alpha and beta rhizobia, including the ngr_b20860 gene of Sinorhizobium fredii NGR234. A ngr_b20860 mutant formed Fix- determinate nodules that developed normally to a late stage of the symbiosis on the host plants Macroptilium atropurpureum and Vigna unguiculata. However an early symbiotic defect was evident during symbiosis with Leucaena leucocephala, producing Fix- indeterminate nodules. The smb20752 and ngr_b20860 genes encode putative 3-hydroxyisobutyryl-CoA (HIB-CoA) hydrolases. HIB-CoA hydrolases are required for l-valine catabolism and appear to prevent the accumulation of toxic metabolic intermediates, particularly methacrylyl-CoA. Evidence presented here and elsewhere (Curson et al., , PLoS ONE 9:e97660) demonstrated that Smb20752 and NGR_b20860 can also prevent metabolic toxicity, are required for l-valine metabolism, and play an undefined role in 3-hydroxybutyrate catabolism. We present evidence that the symbiotic defect of the HIB-CoA hydrolase mutants is independent of the inability to catabolize l-valine and suggest it relates to the toxicity resulting from metabolism of other compounds possibly related to 3-hydroxybutyric acid.
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Affiliation(s)
- Maryam Zamani
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario, Canada, L8S 4K1
| | - George C diCenzo
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario, Canada, L8S 4K1
| | - Branislava Milunovic
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario, Canada, L8S 4K1
| | - Turlough M Finan
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario, Canada, L8S 4K1
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22
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diCenzo GC, Checcucci A, Bazzicalupo M, Mengoni A, Viti C, Dziewit L, Finan TM, Galardini M, Fondi M. Metabolic modelling reveals the specialization of secondary replicons for niche adaptation in Sinorhizobium meliloti. Nat Commun 2016; 7:12219. [PMID: 27447951 PMCID: PMC4961836 DOI: 10.1038/ncomms12219] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 06/10/2016] [Indexed: 12/14/2022] Open
Abstract
The genome of about 10% of bacterial species is divided among two or more large chromosome-sized replicons. The contribution of each replicon to the microbial life cycle (for example, environmental adaptations and/or niche switching) remains unclear. Here we report a genome-scale metabolic model of the legume symbiont Sinorhizobium meliloti that is integrated with carbon utilization data for 1,500 genes with 192 carbon substrates. Growth of S. meliloti is modelled in three ecological niches (bulk soil, rhizosphere and nodule) with a focus on the role of each of its three replicons. We observe clear metabolic differences during growth in the tested ecological niches and an overall reprogramming following niche switching. In silico examination of the inferred fitness of gene deletion mutants suggests that secondary replicons evolved to fulfil a specialized function, particularly host-associated niche adaptation. Thus, genes on secondary replicons might potentially be manipulated to promote or suppress host interactions for biotechnological purposes. The genome of some bacteria consists of two or more chromosomes or replicons. Here, diCenzo et al. integrate genome-scale metabolic modelling and growth data from a collection of mutants of the plant symbiont Sinorhizobium meliloti to estimate the fitness contribution of each replicon in three environments.
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Affiliation(s)
- George C diCenzo
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 1A1
| | - Alice Checcucci
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Marco Bazzicalupo
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Alessio Mengoni
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Carlo Viti
- Department of Agri-food Production and Environmental Sciences, University of Florence, 50144 Sesto Fiorentino, Italy
| | - Lukasz Dziewit
- Department of Bacterial Genetics, Institute of Microbiology, Faculty of Biology, University of Warsaw, 02-096 Warsaw, Poland
| | - Turlough M Finan
- Department of Biology, McMaster University, Hamilton, Ontario, Canada L8S 1A1
| | - Marco Galardini
- EMBL-EBI, Wellcome Trust Genome Campus, Cambridge CB10 1SD, UK
| | - Marco Fondi
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
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23
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diCenzo GC, Zamani M, Milunovic B, Finan TM. Genomic resources for identification of the minimal N2 -fixing symbiotic genome. Environ Microbiol 2016; 18:2534-47. [PMID: 26768651 DOI: 10.1111/1462-2920.13221] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 12/17/2015] [Accepted: 01/09/2016] [Indexed: 12/11/2022]
Abstract
The lack of an appropriate genomic platform has precluded the use of gain-of-function approaches to study the rhizobium-legume symbiosis, preventing the establishment of the genes necessary and sufficient for symbiotic nitrogen fixation (SNF) and potentially hindering synthetic biology approaches aimed at engineering this process. Here, we describe the development of an appropriate system by reverse engineering Sinorhizobium meliloti. Using a novel in vivo cloning procedure, the engA-tRNA-rmlC (ETR) region, essential for cell viability and symbiosis, was transferred from Sinorhizobium fredii to the ancestral location on the S. meliloti chromosome, rendering the ETR region on pSymB redundant. A derivative of this strain lacking both the large symbiotic replicons (pSymA and pSymB) was constructed. Transfer of pSymA and pSymB back into this strain restored symbiotic capabilities with alfalfa. To delineate the location of the single-copy genes essential for SNF on these replicons, we screened a S. meliloti deletion library, representing > 95% of the 2900 genes of the symbiotic replicons, for their phenotypes with alfalfa. Only four loci, accounting for < 12% of pSymA and pSymB, were essential for SNF. These regions will serve as our preliminary target of the minimal set of horizontally acquired genes necessary and sufficient for SNF.
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Affiliation(s)
- George C diCenzo
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario, Canada, L8S 4K1
| | - Maryam Zamani
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario, Canada, L8S 4K1
| | - Branislava Milunovic
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario, Canada, L8S 4K1
| | - Turlough M Finan
- Department of Biology, McMaster University, 1280 Main St. W., Hamilton, Ontario, Canada, L8S 4K1
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L-Hydroxyproline and d-Proline Catabolism in Sinorhizobium meliloti. J Bacteriol 2016; 198:1171-81. [PMID: 26833407 DOI: 10.1128/jb.00961-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 01/25/2016] [Indexed: 01/17/2023] Open
Abstract
UNLABELLED Sinorhizobium meliloti forms N2-fixing root nodules on alfalfa, and as a free-living bacterium, it can grow on a very broad range of substrates, including l-proline and several related compounds, such as proline betaine, trans-4-hydroxy-l-proline (trans-4-l-Hyp), and cis-4-hydroxy-d-proline (cis-4-d-Hyp). Fourteen hyp genes are induced upon growth of S. meliloti on trans-4-l-Hyp, and of those, hypMNPQ encodes an ABC-type trans-4-l-Hyp transporter and hypRE encodes an epimerase that converts trans-4-l-Hyp to cis-4-d-Hyp in the bacterial cytoplasm. Here, we present evidence that the HypO, HypD, and HypH proteins catalyze the remaining steps in which cis-4-d-Hyp is converted to α-ketoglutarate. The HypO protein functions as a d-amino acid dehydrogenase, converting cis-4-d-Hyp to Δ(1)-pyrroline-4-hydroxy-2-carboxylate, which is deaminated by HypD to α-ketoglutarate semialdehyde and then converted to α-ketoglutarate by HypH. The crystal structure of HypD revealed it to be a member of the N-acetylneuraminate lyase subfamily of the (α/β)8 protein family and is consistent with the known enzymatic mechanism for other members of the group. It was also shown that S. meliloti can catabolize d-proline as both a carbon and a nitrogen source, that d-proline can complement l-proline auxotrophy, and that the catabolism of d-proline is dependent on the hyp cluster. Transport of d-proline involves the HypMNPQ transporter, following which d-proline is converted to Δ(1)-pyrroline-2-carboxylate (P2C) largely via HypO. The P2C is converted to l-proline through the NADPH-dependent reduction of P2C by the previously uncharacterized HypS protein. Thus, overall, we have now completed detailed genetic and/or biochemical characterization of 9 of the 14 hyp genes. IMPORTANCE Hydroxyproline is abundant in proteins in animal and plant tissues and serves as a carbon and a nitrogen source for bacteria in diverse environments, including the rhizosphere, compost, and the mammalian gut. While the main biochemical features of bacterial hydroxyproline catabolism were elucidated in the 1960s, the genetic and molecular details have only recently been determined. Elucidating the genetics of hydroxyproline catabolism will aid in the annotation of these genes in other genomes and metagenomic libraries. This will facilitate an improved understanding of the importance of this pathway and may assist in determining the prevalence of hydroxyproline in a particular environment.
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diCenzo GC, Zamani M, Cowie A, Finan TM. Proline auxotrophy in Sinorhizobium meliloti results in a plant-specific symbiotic phenotype. MICROBIOLOGY-SGM 2015; 161:2341-51. [PMID: 26395514 DOI: 10.1099/mic.0.000182] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
In order to effectively manipulate rhizobium-legume symbioses for our benefit, it is crucial to first gain a complete understanding of the underlying genetics and metabolism. Studies with rhizobium auxotrophs have provided insight into the requirement for amino acid biosynthesis during the symbiosis; however, a paucity of available L-proline auxotrophs has limited our understanding of the role of L-proline biosynthesis. Here, we examined the symbiotic phenotypes of a recently described Sinorhizobium meliloti L-proline auxotroph. Proline auxotrophy was observed to result in a host-plant-specific phenotype. The S. meliloti auxotroph displayed reduced symbiotic capability with alfalfa (Medicago sativa) due to a decrease in nodule mass formed and therefore a reduction in nitrogen fixed per plant. However, the proline auxotroph formed nodules on white sweet clover (Melilotus alba) that failed to fix nitrogen. The rate of white sweet clover nodulation by the auxotroph was slightly delayed, but the final number of nodules per plant was not impacted. Examination of white sweet clover nodules by confocal microscopy and transmission electron microscopy revealed the presence of the S. meliloti proline auxotroph cells within the host legume cells, but few differentiated bacteroids were identified compared with the bacteroid-filled plant cells of WT nodules. Overall, these results indicated that L-proline biosynthesis is a general requirement for a fully effective nitrogen-fixing symbiosis, likely due to a transient requirement during bacteroid differentiation.
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Affiliation(s)
- George C diCenzo
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Maryam Zamani
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Alison Cowie
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
| | - Turlough M Finan
- Department of Biology, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
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Hernández VM, Girard L, Hernández-Lucas I, Vázquez A, Ortíz-Ortíz C, Díaz R, Dunn MF. Genetic and biochemical characterization of arginine biosynthesis in Sinorhizobium meliloti 1021. Microbiology (Reading) 2015; 161:1671-1682. [DOI: 10.1099/mic.0.000122] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Victor M. Hernández
- Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos C. P. 62210, Mexico
| | - Lourdes Girard
- Programa de Dinámica Genómica, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos C. P. 62210, Mexico
| | - Ismael Hernández-Lucas
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos C. P. 62210, Mexico
| | - Alejandra Vázquez
- Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Morelos C. P. 62210, Mexico
| | - Catalina Ortíz-Ortíz
- Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos C. P. 62210, Mexico
| | - Rafael Díaz
- Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos C. P. 62210, Mexico
| | - Michael F. Dunn
- Programa de Genómica Funcional de Procariotes, Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos C. P. 62210, Mexico
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