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Sulieman S, Sheteiwy MS, Abdelrahman M, Tran LSP. γ-Aminobutyric acid (GABA) in N 2-fixing-legume symbiosis: Metabolic flux and carbon/nitrogen homeostasis in responses to abiotic constraints. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108362. [PMID: 38266561 DOI: 10.1016/j.plaphy.2024.108362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 12/07/2023] [Accepted: 01/10/2024] [Indexed: 01/26/2024]
Abstract
Nodule symbiosis is an energetic process that demands a tremendous carbon (C) cost, which massively increases in responses to environmental stresses. Notably, most common respiratory pathways (e.g., glycolysis and Krebs cycle) that sustain nitrogenase activity and subsequent nitrogen (N) assimilation (amino acid formation) display a noncyclic mode of C flux. In such circumstances, the nodule's energy charge could markedly decrease, leading to a lower symbiotic activity under stresses. The host plant then attempts to induce alternative robust metabolic pathways to minimize the C expenditure and compensate for the loss in respiratory substrates. GABA (γ-aminobutyric acid) shunt appears to be among the highly conserved metabolic bypass induced in responses to stresses. Thus, it can be suggested that GABA, via its primary biosynthetic pathway (GABA shunt), is simultaneously induced to circumvent stress-susceptible decarboxylating portion of the Krebs cycle and to replenish symbiosome with energy and C skeletons for enhancing nitrogenase activity and N assimilation besides the additional C costs expended in the metabolic stress acclimations (e.g., biosynthesis of secondary metabolites and excretion of anions). The GABA-mediated C/N balance is strongly associated with interrelated processes, including pH regulation, oxygen (O2) protection, osmoregulation, cellular redox control, and N storage. Furthermore, it has been anticipated that GABA could be implicated in other functions beyond its metabolic role (i.e., signaling and transport). GABA helps plants possess remarkable metabolic plasticity, which might thus assist nodules in attenuating stressful events.
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Affiliation(s)
- Saad Sulieman
- Department of Agronomy, Faculty of Agriculture, University of Khartoum, 13314, Shambat, Khartoum North, Sudan.
| | - Mohamed S Sheteiwy
- Department of Integrative Agriculture, College of Agriculture and Veterinary Medicine, United Arab Emirates University, P.O. Box 15551, Al Ain, Abu Dhabi, United Arab Emirates; Department of Agronomy, Faculty of Agriculture, Mansoura University, Mansoura, 35516, Egypt
| | - Mostafa Abdelrahman
- Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, TX, 79409, USA
| | - Lam-Son Phan Tran
- Institute of Genomics for Crop Abiotic Stress Tolerance, Department of Plant and Soil Science, Texas Tech University, TX, 79409, USA.
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Qian M, Han X, Liu J, Xu P, Tao F. Genomic Insights on the Carbon-Negative Workhorse: Systematical Comparative Genomic Analysis on 56 Synechococcus Strains. Bioengineering (Basel) 2023; 10:1329. [PMID: 38002453 PMCID: PMC10669429 DOI: 10.3390/bioengineering10111329] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/31/2023] [Accepted: 11/09/2023] [Indexed: 11/26/2023] Open
Abstract
Synechococcus, a type of ancient photosynthetic cyanobacteria, is crucial in modern carbon-negative synthetic biology due to its potential for producing bioenergy and high-value products. With its high biomass, fast growth rate, and established genetic manipulation tools, Synechococcus has become a research focus in recent years. Abundant germplasm resources have been accumulated from various habitats, including temperature and salinity conditions relevant to industrialization. In this study, a comprehensive analysis of complete genomes of the 56 Synechococcus strains currently available in public databases was performed, clarifying genetic relationships, the adaptability of Synechococcus to the environment, and its reflection at the genomic level. This was carried out via pan-genome analysis and a detailed comparison of the functional gene groups. The results revealed an open-genome pattern, with 275 core genes and variable genome sizes within these strains. The KEGG annotation and orthology composition comparisons unveiled that the cold and thermophile strains have 32 and 84 unique KO functional units in their shared core gene functional units, respectively. Each KO functional unit reflects unique gene families and pathways. In terms of salt tolerance and comparative genomics, there are 65 unique KO functional units in freshwater-adapted strains and 154 in strictly marine strains. By delving into these aspects, our understanding of the metabolic potential of Synechococcus was deepened, promoting the development and industrial application of cyanobacterial biotechnology.
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Affiliation(s)
| | | | | | | | - Fei Tao
- School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; (M.Q.); (X.H.); (J.L.); (P.X.)
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3
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Teoh CP, Lavin P, Yusof NA, González-Aravena M, Najimudin N, Cheah YK, Wong CMVL. Transcriptomics analysis provides insights into the heat adaptation strategies of an Antarctic bacterium, Cryobacterium sp. SO1. Polar Biol 2023. [DOI: 10.1007/s00300-023-03115-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
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A New Face of the Old Gene: Deletion of the PssA, Encoding Monotopic Inner Membrane Phosphoglycosyl Transferase in Rhizobium leguminosarum, Leads to Diverse Phenotypes That Could Be Attributable to Downstream Effects of the Lack of Exopolysaccharide. Int J Mol Sci 2023; 24:ijms24021035. [PMID: 36674551 PMCID: PMC9860679 DOI: 10.3390/ijms24021035] [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: 11/29/2022] [Revised: 01/02/2023] [Accepted: 01/03/2023] [Indexed: 01/06/2023] Open
Abstract
The biosynthesis of subunits of rhizobial exopolysaccharides is dependent on glycosyltransferases, which are usually encoded by large gene clusters. PssA is a member of a large family of phosphoglycosyl transferases catalyzing the transfer of a phosphosugar moiety to polyprenol phosphate; thus, it can be considered as priming glycosyltransferase commencing synthesis of the EPS repeating units in Rhizobium leguminosarum. The comprehensive analysis of PssA protein features performed in this work confirmed its specificity for UDP-glucose and provided evidence that PssA is a monotopic inner membrane protein with a reentrant membrane helix rather than a transmembrane segment. The bacterial two-hybrid system screening revealed interactions of PssA with some GTs involved in the EPS octasaccharide synthesis. The distribution of differentially expressed genes in the transcriptome of the ΔpssA mutant into various functional categories indicated complexity of cell response to the deletion, which can mostly be attributed to the lack of exopolysaccharide and downstream effects caused by such deficiency. The block in the EPS biosynthesis at the pssA step, potentially leading to an increased pool of UDP-glucose, is likely to be filtered through to other pathways, and thus the absence of EPS may indirectly affect the expression of proteins involved in these pathways.
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5
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Wekesa C, Asudi GO, Okoth P, Reichelt M, Muoma JO, Furch ACU, Oelmüller R. Rhizobia Contribute to Salinity Tolerance in Common Beans ( Phaseolus vulgaris L.). Cells 2022; 11:cells11223628. [PMID: 36429056 PMCID: PMC9688157 DOI: 10.3390/cells11223628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/10/2022] [Accepted: 11/14/2022] [Indexed: 11/18/2022] Open
Abstract
Rhizobia are soil bacteria that induce nodule formation on leguminous plants. In the nodules, they reduce dinitrogen to ammonium that can be utilized by plants. Besides nitrogen fixation, rhizobia have other symbiotic functions in plants including phosphorus and iron mobilization and protection of the plants against various abiotic stresses including salinity. Worldwide, about 20% of cultivable and 33% of irrigation land is saline, and it is estimated that around 50% of the arable land will be saline by 2050. Salinity inhibits plant growth and development, results in senescence, and ultimately plant death. The purpose of this study was to investigate how rhizobia, isolated from Kenyan soils, relieve common beans from salinity stress. The yield loss of common bean plants, which were either not inoculated or inoculated with the commercial R. tropici rhizobia CIAT899 was reduced by 73% when the plants were exposed to 300 mM NaCl, while only 60% yield loss was observed after inoculation with a novel indigenous isolate from Kenyan soil, named S3. Expression profiles showed that genes involved in the transport of mineral ions (such as K+, Ca2+, Fe3+, PO43-, and NO3-) to the host plant, and for the synthesis and transport of osmotolerance molecules (soluble carbohydrates, amino acids, and nucleotides) are highly expressed in S3 bacteroids during salt stress than in the controls. Furthermore, genes for the synthesis and transport of glutathione and γ-aminobutyric acid were upregulated in salt-stressed and S3-inocculated common bean plants. We conclude that microbial osmolytes, mineral ions, and antioxidant molecules from rhizobia enhance salt tolerance in common beans.
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Affiliation(s)
- Clabe Wekesa
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich-Schiller-University Jena, Dornburger Str. 159, 07743 Jena, Germany
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany
| | - George O. Asudi
- Department of Biochemistry, Microbiology and Biotechnology, Kenyatta University, P.O. Box 43844, Nairobi 00100, Kenya
| | - Patrick Okoth
- Department of Biological Sciences, Masinde Muliro University of Science and Technology, P.O. Box 190-50100, Kakamega 50100, Kenya
| | - Michael Reichelt
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, 07745 Jena, Germany
| | - John O. Muoma
- Department of Biological Sciences, Masinde Muliro University of Science and Technology, P.O. Box 190-50100, Kakamega 50100, Kenya
| | - Alexandra C. U. Furch
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich-Schiller-University Jena, Dornburger Str. 159, 07743 Jena, Germany
| | - Ralf Oelmüller
- Matthias Schleiden Institute of Genetics, Bioinformatics and Molecular Botany, Friedrich-Schiller-University Jena, Dornburger Str. 159, 07743 Jena, Germany
- Correspondence:
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Wang M, Zhang X, Huang H, Qin Z, Liu C, Chen Y. Amino Acid Configuration Affects Volatile Fatty Acid Production during Proteinaceous Waste Valorization: Chemotaxis, Quorum Sensing, and Metabolism. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:8702-8711. [PMID: 35549463 DOI: 10.1021/acs.est.1c07894] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
During proteinaceous waste valorization to produce volatile fatty acids (VFAs), protein needs to be hydrolyzed to amino acids (AAs), but the effects of the configuration of AAs on their biotransformation and VFA production have not been investigated. In this study, more residual d-AAs than their corresponding l-AAs were observed after VFAs were produced from kitchen waste in a pilot-scale bioreactor. For all AAs investigated, the VFA production from d-AAs was lower than that from corresponding l-AAs. The metagenomics and metaproteomics analyses revealed that the l-AA fermentation system exhibited greater bacterial chemotaxis and quorum sensing (QS) than d-AAs, which benefited the establishment of functional microorganisms (such as Clostridium, Sedimentibacter, and Peptoclostridium) and expression of functional proteins (e.g., substrate transportation cofactors, l-AA dehydrogenase, and acidogenic proteins). In addition, d-AAs need to be racemized to l-AAs before being metabolized, and the difference of VFA production between d-AAs and l-AAs decreased with the increase of racemization activity. The findings of the AA configuration affecting bacterial chemotaxis and QS, which altered microorganism communities and functional protein expression, provided a new insight into the reasons for higher l-AA metabolism than d-AAs and more d-AAs left during VFA production from proteinaceous wastes.
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Affiliation(s)
- Meng Wang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Xuemeng Zhang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Haining Huang
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Zhiyi Qin
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Chao Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
| | - Yinguang Chen
- State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China
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7
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Yurgel SN, Qu Y, Rice JT, Ajeethan N, Zink EM, Brown JM, Purvine S, Lipton MS, Kahn ML. Specialization in a Nitrogen-Fixing Symbiosis: Proteome Differences Between Sinorhizobium medicae Bacteria and Bacteroids. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:1409-1422. [PMID: 34402628 DOI: 10.1094/mpmi-07-21-0180-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Using tandem mass spectrometry (MS/MS), we analyzed the proteome of Sinorhizobium medicae WSM419 growing as free-living cells and in symbiosis with Medicago truncatula. In all, 3,215 proteins were identified, over half of the open reading frames predicted from the genomic sequence. The abundance of 1,361 proteins displayed strong lifestyle bias. In total, 1,131 proteins had similar levels in bacteroids and free-living cells, and the low levels of 723 proteins prevented statistically significant assignments. Nitrogenase subunits comprised approximately 12% of quantified bacteroid proteins. Other major bacteroid proteins included symbiosis-specific cytochromes and FixABCX, which transfer electrons to nitrogenase. Bacteroids had normal levels of proteins involved in amino acid biosynthesis, glycolysis or gluconeogenesis, and the pentose phosphate pathway; however, several amino acid degradation pathways were repressed. This suggests that bacteroids maintain a relatively independent anabolic metabolism. Tricarboxylic acid cycle proteins were highly expressed in bacteroids and no other catabolic pathway emerged as an obvious candidate to supply energy and reductant to nitrogen fixation. Bacterial stress response proteins were induced in bacteroids. Many WSM419 proteins that are not encoded in S. meliloti Rm1021 were detected, and understanding the functions of these proteins might clarify why S. medicae WSM419 forms a more effective symbiosis with M. truncatula than S. meliloti Rm1021.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Svetlana N Yurgel
- Department of Plant, Food and Environmental Sciences, Faculty of Agriculture, Dalhousie University, P.O. Box 550, Truro, Nova Scotia, B2N 5E3, Canada
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, U.S.A
| | - Yi Qu
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, U.S.A
| | - Jennifer T Rice
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, U.S.A
| | - Nivethika Ajeethan
- Department of Plant, Food and Environmental Sciences, Faculty of Agriculture, Dalhousie University, P.O. Box 550, Truro, Nova Scotia, B2N 5E3, Canada
- Faculty of Technology, University of Jaffna, Sri Lanka
| | - Erika M Zink
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, U.S.A
| | - Joseph M Brown
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, U.S.A
| | - Sam Purvine
- Environmental Molecular Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, U.S.A
| | - Mary S Lipton
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, U.S.A
| | - Michael L Kahn
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, U.S.A
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164-6340, U.S.A
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8
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Booth NJ, Smith PMC, Ramesh SA, Day DA. Malate Transport and Metabolism in Nitrogen-Fixing Legume Nodules. Molecules 2021; 26:6876. [PMID: 34833968 PMCID: PMC8618214 DOI: 10.3390/molecules26226876] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 11/22/2022] Open
Abstract
Legumes form a symbiosis with rhizobia, a soil bacterium that allows them to access atmospheric nitrogen and deliver it to the plant for growth. Biological nitrogen fixation occurs in specialized organs, termed nodules, that develop on the legume root system and house nitrogen-fixing rhizobial bacteroids in organelle-like structures termed symbiosomes. The process is highly energetic and there is a large demand for carbon by the bacteroids. This carbon is supplied to the nodule as sucrose, which is broken down in nodule cells to organic acids, principally malate, that can then be assimilated by bacteroids. Sucrose may move through apoplastic and/or symplastic routes to the uninfected cells of the nodule or be directly metabolised at the site of import within the vascular parenchyma cells. Malate must be transported to the infected cells and then across the symbiosome membrane, where it is taken up by bacteroids through a well-characterized dct system. The dicarboxylate transporters on the infected cell and symbiosome membranes have been functionally characterized but remain unidentified. Proteomic and transcriptomic studies have revealed numerous candidates, but more work is required to characterize their function and localise the proteins in planta. GABA, which is present at high concentrations in nodules, may play a regulatory role, but this remains to be explored.
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Affiliation(s)
- Nicholas J. Booth
- College of Science & Engineering, Flinders University, GPO Box 5100, Adelaide, SA 5001, Australia; (N.J.B.); (S.A.R.)
| | | | - Sunita A. Ramesh
- College of Science & Engineering, Flinders University, GPO Box 5100, Adelaide, SA 5001, Australia; (N.J.B.); (S.A.R.)
| | - David A. Day
- College of Science & Engineering, Flinders University, GPO Box 5100, Adelaide, SA 5001, Australia; (N.J.B.); (S.A.R.)
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Waterworth SC, Parker-Nance S, Kwan JC, Dorrington RA. Comparative Genomics Provides Insight into the Function of Broad-Host Range Sponge Symbionts. mBio 2021; 12:e0157721. [PMID: 34519538 PMCID: PMC8546597 DOI: 10.1128/mbio.01577-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/13/2021] [Indexed: 11/20/2022] Open
Abstract
The fossil record indicates that the earliest evidence of extant marine sponges (phylum Porifera) existed during the Cambrian explosion and that their symbiosis with microbes may have begun in their extinct ancestors during the Precambrian period. Many symbionts have adapted to their sponge host, where they perform specific, specialized functions. There are also widely distributed bacterial taxa such as Poribacteria, SAUL, and Tethybacterales that are found in a broad range of invertebrate hosts. Here, we added 11 new genomes to the Tethybacterales order, identified a novel family, and show that functional potential differs between the three Tethybacterales families. We compare the Tethybacterales with the well-characterized Entoporibacteria and show that these symbionts appear to preferentially associate with low-microbial abundance (LMA) and high-microbial abundance (HMA) sponges, respectively. Within these sponges, we show that these symbionts likely perform distinct functions and may have undergone multiple association events, rather than a single association event followed by coevolution. IMPORTANCE Marine sponges often form symbiotic relationships with bacteria that fulfil a specific need within the sponge holobiont, and these symbionts are often conserved within a narrow range of related taxa. To date, there exist only three known bacterial taxa (Entoporibacteria, SAUL, and Tethybacterales) that are globally distributed and found in a broad range of sponge hosts, and little is known about the latter two. We show that the functional potential of broad-host range symbionts is conserved at a family level and that these symbionts have been acquired several times over evolutionary history. Finally, it appears that the Entoporibacteria are associated primarily with high-microbial abundance sponges, while the Tethybacterales associate with low-microbial abundance sponges.
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Affiliation(s)
- Samantha C. Waterworth
- Division of Pharmaceutical Sciences, University of Wisconsin, Madison, Wisconsin, USA
- Department of Biochemistry and Microbiology, Rhodes University, Makhanda, South Africa
| | - Shirley Parker-Nance
- Department of Biochemistry and Microbiology, Rhodes University, Makhanda, South Africa
- South African Environmental Observation Network, Elwandle Coastal Node, Gqeberha (Port Elizabeth), South Africa
| | - Jason C. Kwan
- Division of Pharmaceutical Sciences, University of Wisconsin, Madison, Wisconsin, USA
| | - Rosemary A. Dorrington
- Department of Biochemistry and Microbiology, Rhodes University, Makhanda, South Africa
- South African Institute for Aquatic Biodiversity, Makhanda, South Africa
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10
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Bellabarba A, Bacci G, Decorosi F, Aun E, Azzarello E, Remm M, Giovannetti L, Viti C, Mengoni A, Pini F. Competitiveness for Nodule Colonization in Sinorhizobium meliloti: Combined In Vitro-Tagged Strain Competition and Genome-Wide Association Analysis. mSystems 2021. [PMID: 34313466 DOI: 10.1101/2020.09.15.298034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023] Open
Abstract
Associations between leguminous plants and symbiotic nitrogen-fixing rhizobia are a classic example of mutualism between a eukaryotic host and a specific group of prokaryotic microbes. Although this symbiosis is in part species specific, different rhizobial strains may colonize the same nodule. Some rhizobial strains are commonly known as better competitors than others, but detailed analyses that aim to predict rhizobial competitive abilities based on genomes are still scarce. Here, we performed a bacterial genome-wide association (GWAS) analysis to define the genomic determinants related to the competitive capabilities in the model rhizobial species Sinorhizobium meliloti. For this, 13 tester strains were green fluorescent protein (GFP) tagged and assayed versus 3 red fluorescent protein (RFP)-tagged reference competitor strains (Rm1021, AK83, and BL225C) in a Medicago sativa nodule occupancy test. Competition data and strain genomic sequences were employed to build a model for GWAS based on k-mers. Among the k-mers with the highest scores, 51 k-mers mapped on the genomes of four strains showing the highest competition phenotypes (>60% single strain nodule occupancy; GR4, KH35c, KH46, and SM11) versus BL225C. These k-mers were mainly located on the symbiosis-related megaplasmid pSymA, specifically on genes coding for transporters, proteins involved in the biosynthesis of cofactors, and proteins related to metabolism (e.g., fatty acids). The same analysis was performed considering the sum of single and mixed nodules obtained in the competition assays versus BL225C, retrieving k-mers mapped on the genes previously found and on vir genes. Therefore, the competition abilities seem to be linked to multiple genetic determinants and comprise several cellular components. IMPORTANCE Decoding the competitive pattern that occurs in the rhizosphere is challenging in the study of bacterial social interaction strategies. To date, the single-gene approach has mainly been used to uncover the bases of nodulation, but there is still a knowledge gap regarding the main features that a priori characterize rhizobial strains able to outcompete indigenous rhizobia. Therefore, tracking down which traits make different rhizobial strains able to win the competition for plant infection over other indigenous rhizobia will improve the strain selection process and, consequently, plant yield in sustainable agricultural production systems. We proved that a k-mer-based GWAS approach can efficiently identify the competition determinants of a panel of strains previously analyzed for their plant tissue occupancy using double fluorescent labeling. The reported strategy will be useful for detailed studies on the genomic aspects of the evolution of bacterial symbiosis and for an extensive evaluation of rhizobial inoculants.
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Affiliation(s)
- Agnese Bellabarba
- Department of Agronomy, Food, Environmental and Forestry (DAGRI), University of Florencegrid.8404.8, Sesto Fiorentino, Italy
- Genexpress Laboratory, Department of Agronomy, Food, Environmental and Forestry (DAGRI), University of Florencegrid.8404.8, Sesto Fiorentino, Italy
| | - Giovanni Bacci
- Department of Biology, University of Florencegrid.8404.8, Sesto Fiorentino, Italy
| | - Francesca Decorosi
- Department of Agronomy, Food, Environmental and Forestry (DAGRI), University of Florencegrid.8404.8, Sesto Fiorentino, Italy
- Genexpress Laboratory, Department of Agronomy, Food, Environmental and Forestry (DAGRI), University of Florencegrid.8404.8, Sesto Fiorentino, Italy
| | - Erki Aun
- Department of Bioinformatics, Institute of Molecular and Cell Biology, University of Tartugrid.10939.32, Tartu, Estonia
| | - Elisa Azzarello
- Department of Agronomy, Food, Environmental and Forestry (DAGRI), University of Florencegrid.8404.8, Sesto Fiorentino, Italy
| | - Maido Remm
- Department of Bioinformatics, Institute of Molecular and Cell Biology, University of Tartugrid.10939.32, Tartu, Estonia
| | - Luciana Giovannetti
- Department of Agronomy, Food, Environmental and Forestry (DAGRI), University of Florencegrid.8404.8, Sesto Fiorentino, Italy
- Genexpress Laboratory, Department of Agronomy, Food, Environmental and Forestry (DAGRI), University of Florencegrid.8404.8, Sesto Fiorentino, Italy
| | - Carlo Viti
- Department of Agronomy, Food, Environmental and Forestry (DAGRI), University of Florencegrid.8404.8, Sesto Fiorentino, Italy
- Genexpress Laboratory, Department of Agronomy, Food, Environmental and Forestry (DAGRI), University of Florencegrid.8404.8, Sesto Fiorentino, Italy
| | - Alessio Mengoni
- Department of Biology, University of Florencegrid.8404.8, Sesto Fiorentino, Italy
| | - Francesco Pini
- Department of Biology, University of Bari Aldo Morogrid.7644.1, Bari, Italy
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11
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Herruzo-Ruiz AM, Fuentes-Almagro CA, Jiménez-Pastor JM, Pérez-Rosa VM, Blasco J, Michán C, Alhama J. Meta-omic evaluation of bacterial microbial community structure and activity for the environmental assessment of soils: overcoming protein extraction pitfalls. Environ Microbiol 2021; 23:4706-4725. [PMID: 34258847 DOI: 10.1111/1462-2920.15673] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 07/08/2021] [Accepted: 07/11/2021] [Indexed: 11/27/2022]
Abstract
Microorganisms play unique, essential and integral roles in the biosphere. This work aims to assess the utility of soil's metaomics for environmental diagnosis. Doñana National Park (DNP) was selected as a natural lab since it contains a strictly protected core that is surrounded by numerous threats of pollution. Culture-independent high-throughput molecular tools were used to evaluate the alterations of the global structure and metabolic activities of the microbiome. 16S rRNA sequencing shows lower bacterial abundance and diversity in areas historically exposed to contamination that surround DNP. For metaproteomics, an innovative post-alkaline protein extraction protocol was developed. After NaOH treatment, successive washing with Tris-HCl buffer supplemented with glycerol was essential to eliminate interferences. Starting from soils with different physicochemical characteristics, the method renders proteins with a remarkable resolution on SDS-PAGE gels. The proteins extracted were analysed by using an in-house database constructed from the rRNA data. LC-MS/MS analysis identified 2182 non-redundant proteins with 135 showing significant differences in relative abundance in the soils around DNP. Relevant global biological processes were altered in response to the environmental changes, such as protective and antioxidant mechanisms, translation, folding and homeostasis of proteins, membrane transport and aerobic respiratory metabolism.
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Affiliation(s)
- Ana M Herruzo-Ruiz
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario CeiA3, Universidad de Córdoba, Campus de Rabanales, Edificio Severo Ochoa, Córdoba, E-14071, Spain
| | | | - José M Jiménez-Pastor
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario CeiA3, Universidad de Córdoba, Campus de Rabanales, Edificio Severo Ochoa, Córdoba, E-14071, Spain
| | - Víctor M Pérez-Rosa
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario CeiA3, Universidad de Córdoba, Campus de Rabanales, Edificio Severo Ochoa, Córdoba, E-14071, Spain
| | - Julián Blasco
- Department of Ecology and Coastal Management, ICMAN-CSIC, Campus Rio San Pedro, Puerto Real, E-11510, Spain
| | - Carmen Michán
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario CeiA3, Universidad de Córdoba, Campus de Rabanales, Edificio Severo Ochoa, Córdoba, E-14071, Spain
| | - José Alhama
- Departamento de Bioquímica y Biología Molecular, Campus de Excelencia Internacional Agroalimentario CeiA3, Universidad de Córdoba, Campus de Rabanales, Edificio Severo Ochoa, Córdoba, E-14071, Spain
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12
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Competitiveness for Nodule Colonization in Sinorhizobium meliloti: Combined In Vitro-Tagged Strain Competition and Genome-Wide Association Analysis. mSystems 2021; 6:e0055021. [PMID: 34313466 PMCID: PMC8407117 DOI: 10.1128/msystems.00550-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Associations between leguminous plants and symbiotic nitrogen-fixing rhizobia are a classic example of mutualism between a eukaryotic host and a specific group of prokaryotic microbes. Although this symbiosis is in part species specific, different rhizobial strains may colonize the same nodule. Some rhizobial strains are commonly known as better competitors than others, but detailed analyses that aim to predict rhizobial competitive abilities based on genomes are still scarce. Here, we performed a bacterial genome-wide association (GWAS) analysis to define the genomic determinants related to the competitive capabilities in the model rhizobial species Sinorhizobium meliloti. For this, 13 tester strains were green fluorescent protein (GFP) tagged and assayed versus 3 red fluorescent protein (RFP)-tagged reference competitor strains (Rm1021, AK83, and BL225C) in a Medicago sativa nodule occupancy test. Competition data and strain genomic sequences were employed to build a model for GWAS based on k-mers. Among the k-mers with the highest scores, 51 k-mers mapped on the genomes of four strains showing the highest competition phenotypes (>60% single strain nodule occupancy; GR4, KH35c, KH46, and SM11) versus BL225C. These k-mers were mainly located on the symbiosis-related megaplasmid pSymA, specifically on genes coding for transporters, proteins involved in the biosynthesis of cofactors, and proteins related to metabolism (e.g., fatty acids). The same analysis was performed considering the sum of single and mixed nodules obtained in the competition assays versus BL225C, retrieving k-mers mapped on the genes previously found and on vir genes. Therefore, the competition abilities seem to be linked to multiple genetic determinants and comprise several cellular components. IMPORTANCE Decoding the competitive pattern that occurs in the rhizosphere is challenging in the study of bacterial social interaction strategies. To date, the single-gene approach has mainly been used to uncover the bases of nodulation, but there is still a knowledge gap regarding the main features that a priori characterize rhizobial strains able to outcompete indigenous rhizobia. Therefore, tracking down which traits make different rhizobial strains able to win the competition for plant infection over other indigenous rhizobia will improve the strain selection process and, consequently, plant yield in sustainable agricultural production systems. We proved that a k-mer-based GWAS approach can efficiently identify the competition determinants of a panel of strains previously analyzed for their plant tissue occupancy using double fluorescent labeling. The reported strategy will be useful for detailed studies on the genomic aspects of the evolution of bacterial symbiosis and for an extensive evaluation of rhizobial inoculants.
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Schulte CCM, Borah K, Wheatley RM, Terpolilli JJ, Saalbach G, Crang N, de Groot DH, Ratcliffe RG, Kruger NJ, Papachristodoulou A, Poole PS. Metabolic control of nitrogen fixation in rhizobium-legume symbioses. SCIENCE ADVANCES 2021; 7:7/31/eabh2433. [PMID: 34330708 PMCID: PMC8324050 DOI: 10.1126/sciadv.abh2433] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 06/14/2021] [Indexed: 05/16/2023]
Abstract
Rhizobia induce nodule formation on legume roots and differentiate into bacteroids, which catabolize plant-derived dicarboxylates to reduce atmospheric N2 into ammonia. Despite the agricultural importance of this symbiosis, the mechanisms that govern carbon and nitrogen allocation in bacteroids and promote ammonia secretion to the plant are largely unknown. Using a metabolic model derived from genome-scale datasets, we show that carbon polymer synthesis and alanine secretion by bacteroids facilitate redox balance in microaerobic nodules. Catabolism of dicarboxylates induces not only a higher oxygen demand but also a higher NADH/NAD+ ratio than sugars. Modeling and 13C metabolic flux analysis indicate that oxygen limitation restricts the decarboxylating arm of the tricarboxylic acid cycle, which limits ammonia assimilation into glutamate. By tightly controlling oxygen supply and providing dicarboxylates as the energy and electron source donors for N2 fixation, legumes promote ammonia secretion by bacteroids. This is a defining feature of rhizobium-legume symbioses.
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Affiliation(s)
- Carolin C M Schulte
- Department of Plant Sciences, University of Oxford, Oxford, UK
- Department of Engineering Science, University of Oxford, Oxford, UK
| | - Khushboo Borah
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | | | | | | | - Nick Crang
- Department of Plant Sciences, University of Oxford, Oxford, UK
| | - Daan H de Groot
- Systems Biology Lab, AIMMS, Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | | | | | | | - Philip S Poole
- Department of Plant Sciences, University of Oxford, Oxford, UK.
- John Innes Centre, Norwich Research Park, Norwich, UK
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14
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Haber M, Burgsdorf I, Handley KM, Rubin-Blum M, Steindler L. Genomic Insights Into the Lifestyles of Thaumarchaeota Inside Sponges. Front Microbiol 2021; 11:622824. [PMID: 33537022 PMCID: PMC7848895 DOI: 10.3389/fmicb.2020.622824] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Accepted: 12/14/2020] [Indexed: 11/28/2022] Open
Abstract
Sponges are among the oldest metazoans and their success is partly due to their abundant and diverse microbial symbionts. They are one of the few animals that have Thaumarchaeota symbionts. Here we compare genomes of 11 Thaumarchaeota sponge symbionts, including three new genomes, to free-living ones. Like their free-living counterparts, sponge-associated Thaumarchaeota can oxidize ammonia, fix carbon, and produce several vitamins. Adaptions to life inside the sponge host include enrichment in transposases, toxin-antitoxin systems and restriction modifications systems, enrichments previously reported also from bacterial sponge symbionts. Most thaumarchaeal sponge symbionts lost the ability to synthesize rhamnose, which likely alters their cell surface and allows them to evade digestion by the host. All but one archaeal sponge symbiont encoded a high-affinity, branched-chain amino acid transporter system that was absent from the analyzed free-living thaumarchaeota suggesting a mixotrophic lifestyle for the sponge symbionts. Most of the other unique features found in sponge-associated Thaumarchaeota, were limited to only a few specific symbionts. These features included the presence of exopolyphosphatases and a glycine cleavage system found in the novel genomes. Thaumarchaeota have thus likely highly specific interactions with their sponge host, which is supported by the limited number of host sponge species to which each of these symbionts is restricted.
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Affiliation(s)
- Markus Haber
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
- Department of Aquatic Microbial Ecology, Institute of Hydrobiology, Biology Centre CAS, České Budějovice, Czechia
| | - Ilia Burgsdorf
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
| | - Kim M. Handley
- School of Biological Sciences, The University of Auckland, Auckland, New Zealand
| | - Maxim Rubin-Blum
- Israel Oceanographic and Limnological Research Institute, Haifa, Israel
| | - Laura Steindler
- Department of Marine Biology, Leon H. Charney School of Marine Sciences, University of Haifa, Haifa, Israel
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15
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Ecophysiological Study of Paraburkholderia sp. Strain 1N under Soil Solution Conditions: Dynamic Substrate Preferences and Characterization of Carbon Use Efficiency. Appl Environ Microbiol 2020; 86:AEM.01851-20. [PMID: 33008817 PMCID: PMC7688210 DOI: 10.1128/aem.01851-20] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/24/2020] [Indexed: 11/20/2022] Open
Abstract
We used time-resolved metabolic footprinting, an important technical approach used to monitor changes in extracellular compound concentrations during microbial growth, to study the order of substrate utilization (i.e., substrate preferences) and kinetics of a fast-growing soil isolate, Paraburkholderia sp. strain 1N. The growth of Paraburkholderia sp. 1N was monitored under aerobic conditions in a soil-extracted solubilized organic matter medium, representing a realistic diversity of available substrates and gradient of initial concentrations. We combined multiple analytical approaches to track over 150 compounds in the medium and complemented this with bulk carbon and nitrogen measurements, allowing estimates of carbon use efficiency throughout the growth curve. Targeted methods allowed the quantification of common low-molecular-weight substrates: glucose, 20 amino acids, and 9 organic acids. All targeted compounds were depleted from the medium, and depletion followed a sigmoidal curve where sufficient data were available. Substrates were utilized in at least three distinct temporal clusters as Paraburkholderia sp. 1N produced biomass at a cumulative carbon use efficiency of 0.43. The two substrates with highest initial concentrations, glucose and valine, exhibited longer usage windows, at higher biomass-normalized rates, and later in the growth curve. Contrary to hypotheses based on previous studies, we found no clear relationship between substrate nominal oxidation state of carbon (NOSC) or maximal growth rate and the order of substrate depletion. Under soil solution conditions, the growth of Paraburkholderia sp. 1N induced multiauxic substrate depletion patterns that could not be explained by the traditional paradigm of catabolite repression.IMPORTANCE Exometabolomic footprinting methods have the capability to provide time-resolved observations of the uptake and release of hundreds of compounds during microbial growth. Of particular interest is microbial phenotyping under environmentally relevant soil conditions, consisting of relatively low concentrations and modeling pulse input events. Here, we show that growth of a bacterial soil isolate, Paraburkholderia sp. 1N, on a dilute soil extract resulted in a multiauxic metabolic response, characterized by discrete temporal clusters of substrate depletion and metabolite production. Our data did not support the hypothesis that compounds with lower energy content are used preferentially, as each cluster contained compounds with a range of nominal oxidation states of carbon. These new findings with Paraburkholderia sp. 1N, which belongs to a metabolically diverse genus, provide insights on ecological strategies employed by aerobic heterotrophs competing for low-molecular-weight substrates in soil solution.
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Abstract
By analyzing successive lifestyle stages of a model Rhizobium-legume symbiosis using mariner-based transposon insertion sequencing (INSeq), we have defined the genes required for rhizosphere growth, root colonization, bacterial infection, N2-fixing bacteroids, and release from legume (pea) nodules. While only 27 genes are annotated as nif and fix in Rhizobium leguminosarum, we show 603 genetic regions (593 genes, 5 transfer RNAs, and 5 RNA features) are required for the competitive ability to nodulate pea and fix N2 Of these, 146 are common to rhizosphere growth through to bacteroids. This large number of genes, defined as rhizosphere-progressive, highlights how critical successful competition in the rhizosphere is to subsequent infection and nodulation. As expected, there is also a large group (211) specific for nodule bacteria and bacteroid function. Nodule infection and bacteroid formation require genes for motility, cell envelope restructuring, nodulation signaling, N2 fixation, and metabolic adaptation. Metabolic adaptation includes urea, erythritol and aldehyde metabolism, glycogen synthesis, dicarboxylate metabolism, and glutamine synthesis (GlnII). There are 17 separate lifestyle adaptations specific to rhizosphere growth and 23 to root colonization, distinct from infection and nodule formation. These results dramatically highlight the importance of competition at multiple stages of a Rhizobium-legume symbiosis.
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17
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Diauxie and co-utilization of carbon sources can coexist during bacterial growth in nutritionally complex environments. Nat Commun 2020; 11:3135. [PMID: 32561713 PMCID: PMC7305145 DOI: 10.1038/s41467-020-16872-8] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 05/26/2020] [Indexed: 12/14/2022] Open
Abstract
It is commonly thought that when multiple carbon sources are available, bacteria metabolize them either sequentially (diauxic growth) or simultaneously (co-utilization). However, this view is mainly based on analyses in relatively simple laboratory settings. Here we show that a heterotrophic marine bacterium, Pseudoalteromonas haloplanktis, can use both strategies simultaneously when multiple possible nutrients are provided in the same growth experiment. The order of nutrient uptake is partially determined by the biomass yield that can be achieved when the same compounds are provided as single carbon sources. Using transcriptomics and time-resolved intracellular 1H-13C NMR, we reveal specific pathways for utilization of various amino acids. Finally, theoretical modelling indicates that this metabolic phenotype, combining diauxie and co-utilization of substrates, is compatible with a tight regulation that allows the modulation of assimilatory pathways. It is thought that when multiple carbon sources are available, bacteria metabolize them either sequentially or simultaneously. Here, the authors show that a marine bacterium can use a mixed strategy when multiple possible nutrients are provided, and analyse the metabolic pathways involved.
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18
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Abreu I, Mihelj P, Raimunda D. Transition metal transporters in rhizobia: tuning the inorganic micronutrient requirements to different living styles. Metallomics 2020; 11:735-755. [PMID: 30734808 DOI: 10.1039/c8mt00372f] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A group of bacteria known as rhizobia are key players in symbiotic nitrogen fixation (SNF) in partnership with legumes. After a molecular exchange, the bacteria end surrounded by a plant membrane forming symbiosomes, organelle-like structures, where they differentiate to bacteroids and fix nitrogen. This symbiotic process is highly dependent on dynamic nutrient exchanges between the partners. Among these are transition metals (TM) participating as inorganic and organic cofactors of fundamental enzymes. While the understanding of how plant transporters facilitate TMs to the very near environment of the bacteroid is expanding, our knowledge on how bacteroid transporters integrate to TM homeostasis mechanisms in the plant host is still limited. This is significantly relevant considering the low solubility and scarcity of TMs in soils, and the in crescendo gradient of TM bioavailability rhizobia faces during the infection and bacteroid differentiation processes. In the present work, we review the main metal transporter families found in rhizobia, their role in free-living conditions and, when known, in symbiosis. We focus on discussing those transporters which could play a significant role in TM-dependent biochemical and physiological processes in the bacteroid, thus paving the way towards an optimized SNF.
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Affiliation(s)
- Isidro Abreu
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
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19
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Global control of bacterial nitrogen and carbon metabolism by a PTS Ntr-regulated switch. Proc Natl Acad Sci U S A 2020; 117:10234-10245. [PMID: 32341157 DOI: 10.1073/pnas.1917471117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The nitrogen-related phosphotransferase system (PTSNtr) of Rhizobium leguminosarum bv. viciae 3841 transfers phosphate from PEP via PtsP and NPr to two output regulators, ManX and PtsN. ManX controls central carbon metabolism via the tricarboxylic acid (TCA) cycle, while PtsN controls nitrogen uptake, exopolysaccharide production, and potassium homeostasis, each of which is critical for cellular adaptation and survival. Cellular nitrogen status modulates phosphorylation when glutamine, an abundant amino acid when nitrogen is available, binds to the GAF sensory domain of PtsP, preventing PtsP phosphorylation and subsequent modification of ManX and PtsN. Under nitrogen-rich, carbon-limiting conditions, unphosphorylated ManX stimulates the TCA cycle and carbon oxidation, while unphosphorylated PtsN stimulates potassium uptake. The effects are reversed with the phosphorylation of ManX and PtsN, occurring under nitrogen-limiting, carbon-rich conditions; phosphorylated PtsN triggers uptake and nitrogen metabolism, the TCA cycle and carbon oxidation are decreased, while carbon-storage polymers such as surface polysaccharide are increased. Deleting the GAF domain from PtsP makes cells "blind" to the cellular nitrogen status. PTSNtr constitutes a switch through which carbon and nitrogen metabolism are rapidly, and reversibly, regulated by protein:protein interactions. PTSNtr is widely conserved in proteobacteria, highlighting its global importance.
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20
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Speck JJ, James EK, Sugawara M, Sadowsky MJ, Gyaneshwar P. An Alkane Sulfonate Monooxygenase Is Required for Symbiotic Nitrogen Fixation by Bradyrhizobium diazoefficiens (syn. Bradyrhizobium japonicum) USDA110 T. Appl Environ Microbiol 2019; 85:e01552-19. [PMID: 31562172 PMCID: PMC6881790 DOI: 10.1128/aem.01552-19] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2019] [Accepted: 09/25/2019] [Indexed: 01/18/2023] Open
Abstract
Sulfur (S)-containing molecules play an important role in symbiotic nitrogen fixation and are critical components of nitrogenase and other iron-S proteins. S deficiency inhibits symbiotic nitrogen fixation by rhizobia. However, despite its importance, little is known about the sources of S that rhizobia utilize during symbiosis. We previously showed that Bradyrhizobium diazoefficiens USDA110T can assimilate both inorganic and organic S and that genes involved in organic S utilization are expressed during symbiosis. Here, we show that a B. diazoefficiens USDA110T mutant with a sulfonate monooxygenase (ssuD) insertion is defective in nitrogen fixation. Microscopy analyses revealed that the ΔssuD mutant was defective in root hair infection and that ΔssuD mutant bacteroids showed degradation compared to the wild-type strain. Moreover, the ΔssuD mutant was significantly more sensitive to hydrogen peroxide-mediated oxidative stress than the wild-type strain. Taken together, these results show that the ability of rhizobia to utilize organic S plays an important role in symbiotic nitrogen fixation. Since nodules have been reported to be an important source of reduced S used during symbiosis and nitrogen fixation, further research will be needed to determine the mechanisms involved in the regulation of S assimilation by rhizobia.IMPORTANCE Rhizobia form symbiotic associations with legumes that lead to the formation of nitrogen-fixing nodules. Sulfur-containing molecules play a crucial role in nitrogen fixation; thus, the rhizobia inside nodules require large amounts of sulfur. Rhizobia can assimilate both inorganic (sulfate) and organic (sulfonates) sources of sulfur. However, very little is known about rhizobial sulfur metabolism during symbiosis. In this report, we show that sulfonate utilization by Bradyrhizobium diazoefficiens is important for symbiotic nitrogen fixation in both soybean and cowpea. The symbiotic defect is probably due to increased sensitivity to oxidative stress from sulfur deficiency in the mutant strain defective for sulfonate utilization. The results of this study can be extended to other rhizobium-legume symbioses, as sulfonate utilization genes are widespread in these bacteria.
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Affiliation(s)
- Justin J Speck
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
| | | | - Masayuki Sugawara
- Biotechnology Institute, Department of Soil, Water & Climate, University of Minnesota, Saint Paul, Minnesota, USA
- Graduate School of Life Sciences, Tohoku University, Sendai, Japan
- Biotechnology Institute, Department of Plant & Microbial Biology, University of Minnesota, Saint Paul, Minnesota, USA
| | - Michael J Sadowsky
- Biotechnology Institute, Department of Soil, Water & Climate, University of Minnesota, Saint Paul, Minnesota, USA
- Biotechnology Institute, Department of Plant & Microbial Biology, University of Minnesota, Saint Paul, Minnesota, USA
| | - Prasad Gyaneshwar
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, Wisconsin, USA
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21
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Moeller FU, Webster NS, Herbold CW, Behnam F, Domman D, Albertsen M, Mooshammer M, Markert S, Turaev D, Becher D, Rattei T, Schweder T, Richter A, Watzka M, Nielsen PH, Wagner M. Characterization of a thaumarchaeal symbiont that drives incomplete nitrification in the tropical sponge Ianthella basta. Environ Microbiol 2019; 21:3831-3854. [PMID: 31271506 PMCID: PMC6790972 DOI: 10.1111/1462-2920.14732] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 06/14/2019] [Accepted: 06/17/2019] [Indexed: 12/25/2022]
Abstract
Marine sponges represent one of the few eukaryotic groups that frequently harbour symbiotic members of the Thaumarchaeota, which are important chemoautotrophic ammonia-oxidizers in many environments. However, in most studies, direct demonstration of ammonia-oxidation by these archaea within sponges is lacking, and little is known about sponge-specific adaptations of ammonia-oxidizing archaea (AOA). Here, we characterized the thaumarchaeal symbiont of the marine sponge Ianthella basta using metaproteogenomics, fluorescence in situ hybridization, qPCR and isotope-based functional assays. 'Candidatus Nitrosospongia ianthellae' is only distantly related to cultured AOA. It is an abundant symbiont that is solely responsible for nitrite formation from ammonia in I. basta that surprisingly does not harbour nitrite-oxidizing microbes. Furthermore, this AOA is equipped with an expanded set of extracellular subtilisin-like proteases, a metalloprotease unique among archaea, as well as a putative branched-chain amino acid ABC transporter. This repertoire is strongly indicative of a mixotrophic lifestyle and is (with slight variations) also found in other sponge-associated, but not in free-living AOA. We predict that this feature as well as an expanded and unique set of secreted serpins (protease inhibitors), a unique array of eukaryotic-like proteins, and a DNA-phosporothioation system, represent important adaptations of AOA to life within these ancient filter-feeding animals.
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Affiliation(s)
- Florian U. Moeller
- Centre for Microbiology and Environmental Systems Science, Division of Microbial EcologyUniversity of ViennaAustria
| | - Nicole S. Webster
- Australian Institute of Marine ScienceTownsvilleQueenslandAustralia
- Australian Centre for Ecogenomics, School of Chemistry and Molecular BiosciencesUniversity of QueenslandSt LuciaQueenslandAustralia
| | - Craig W. Herbold
- Centre for Microbiology and Environmental Systems Science, Division of Microbial EcologyUniversity of ViennaAustria
| | - Faris Behnam
- Centre for Microbiology and Environmental Systems Science, Division of Microbial EcologyUniversity of ViennaAustria
| | - Daryl Domman
- Centre for Microbiology and Environmental Systems Science, Division of Microbial EcologyUniversity of ViennaAustria
| | - Mads Albertsen
- Center for Microbial Communities, Department of Chemistry and BioscienceAalborg University9220AalborgDenmark
| | - Maria Mooshammer
- Centre for Microbiology and Environmental Systems Science, Division of Microbial EcologyUniversity of ViennaAustria
| | - Stephanie Markert
- Institute of Marine Biotechnology e.VGreifswaldGermany
- Institute of Pharmacy, Pharmaceutical BiotechnologyUniversity of GreifswaldGreifswaldGermany
| | - Dmitrij Turaev
- Centre for Microbiology and Environmental Systems Science, Division of Computational Systems BiologyUniversity of ViennaAustria
| | - Dörte Becher
- Institute of Microbiology, Microbial ProteomicsUniversity of GreifswaldGreifswaldGermany
| | - Thomas Rattei
- Centre for Microbiology and Environmental Systems Science, Division of Computational Systems BiologyUniversity of ViennaAustria
| | - Thomas Schweder
- Institute of Marine Biotechnology e.VGreifswaldGermany
- Institute of Pharmacy, Pharmaceutical BiotechnologyUniversity of GreifswaldGreifswaldGermany
| | - Andreas Richter
- Centre for Microbiology and Environmental Systems Science, Division of Terrestrial Ecosystem ResearchUniversity of ViennaAustria
| | - Margarete Watzka
- Centre for Microbiology and Environmental Systems Science, Division of Terrestrial Ecosystem ResearchUniversity of ViennaAustria
| | - Per Halkjaer Nielsen
- Center for Microbial Communities, Department of Chemistry and BioscienceAalborg University9220AalborgDenmark
| | - Michael Wagner
- Centre for Microbiology and Environmental Systems Science, Division of Microbial EcologyUniversity of ViennaAustria
- Center for Microbial Communities, Department of Chemistry and BioscienceAalborg University9220AalborgDenmark
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22
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Farci D, Sanna C, Medda R, Pintus F, Kalaji HM, Kirkpatrick J, Piano D. Shedding light on the presymbiontic phase of C. arietinum. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 143:224-231. [PMID: 31521050 DOI: 10.1016/j.plaphy.2019.09.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/08/2019] [Accepted: 09/08/2019] [Indexed: 06/10/2023]
Abstract
A complex network of symbiotic events between plants and bacteria allows the biosphere to exploit the atmospheric reservoir of molecular nitrogen. In seeds, a series of presymbiotic steps are already identified during imbibition, while interactions between the host and its symbiont begin in the early stages of germination. In the present study, a detailed analysis of the substances' complex delivered by Cicer arietinum seeds during imbibition showed a relevant presence of proteins and amino acids, which, except for cysteine, occurred with the whole proteinogenic pool. The imbibing solution was found to provide essential probiotic properties able to sustain the growth of the specific chickpea symbiont Mesorhizobium ciceri. Moreover, the imbibing solution, behaving as a complete medium, was found to be critically important for the symbiont's attraction, a fact this that is strictly related to the presence of the amino acids glycine, serine, and threonine. Here, the presence of these amino acids is constantly supported by the presence of the enzymes serine hydroxymethyltransferase and formyltetrahydrofolate deformylase, which are both involved in their biosynthesis. The reported findings are discussed in the light of the pivotal role played by the imbibing solution in attracting and sustaining symbiosis between the host and its symbiont.
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Affiliation(s)
- Domenica Farci
- Laboratory of Plant Physiology and Photobiology, Department of Life and Environmental Sciences, University of Cagliari, V.le S. Ignazio da Laconi 13, 09123, Cagliari, Italy; White Hill Company, Ciołkowskiego 161, 15-545, Białystok, Poland; Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Nowoursynowska Str. 159, 02776, Warsaw, Poland
| | - Cinzia Sanna
- Laboratory of Pharmaceutical Botany, Department of Life and Environmental Sciences, University of Cagliari, V.le S. Ignazio da Laconi 13, 09123, Cagliari, Italy
| | - Rosaria Medda
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria, 09042, Monserrato, Italy
| | - Francesca Pintus
- Department of Life and Environmental Sciences, University of Cagliari, Cittadella Universitaria, 09042, Monserrato, Italy
| | - Hazem M Kalaji
- White Hill Company, Ciołkowskiego 161, 15-545, Białystok, Poland; Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Nowoursynowska Str. 159, 02776, Warsaw, Poland
| | - Joanna Kirkpatrick
- Leibniz Institute on Aging - Fritz Lipmann Institute, Beutenbergstraβe 11, 07745, Jena, Germany
| | - Dario Piano
- Laboratory of Plant Physiology and Photobiology, Department of Life and Environmental Sciences, University of Cagliari, V.le S. Ignazio da Laconi 13, 09123, Cagliari, Italy; Department of Plant Physiology, Warsaw University of Life Sciences - SGGW, Nowoursynowska Str. 159, 02776, Warsaw, Poland.
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23
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Noell SE, Giovannoni SJ. SAR11 bacteria have a high affinity and multifunctional glycine betaine transporter. Environ Microbiol 2019; 21:2559-2575. [PMID: 31090982 DOI: 10.1111/1462-2920.14649] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 05/06/2019] [Indexed: 11/29/2022]
Abstract
Marine bacterioplankton face stiff competition for limited nutrient resources. SAR11, a ubiquitous clade of very small and highly abundant Alphaproteobacteria, are known to devote much of their energy to synthesizing ATP-binding cassette periplasmic proteins that bind substrates. We hypothesized that their small size and relatively large periplasmic space might enable them to outcompete other bacterioplankton for nutrients. Using uptake experiments with 14 C-glycine betaine, we discovered that two strains of SAR11, Candidatus Pelagibacter sp. HTCC7211 and Cand. P. ubique HTCC1062, have extraordinarily high affinity for glycine betaine (GBT), with half-saturation (K s ) values around 1 nM and specific affinity values between 8 and 14 L mg cell-1 h-1 . Competitive inhibition studies indicated that the GBT transporters in these strains are multifunctional, transporting multiple substrates in addition to GBT. Both strains could use most of the transported compounds for metabolism and ATP production. Our findings indicate that Pelagibacter cells are primarily responsible for the high affinity and multifunctional GBT uptake systems observed in seawater. Maximization of whole-cell affinities may enable these organisms to compete effectively for nutrients during periods when the gross transport capacity of the heterotrophic plankton community exceeds the supply, depressing ambient concentrations.
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Affiliation(s)
- Stephen E Noell
- Department of Microbiology, Oregon State University, Corvallis, OR, USA
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Wang H, Yang Y, Xu J, Kong D, Li Y. iTRAQ-based comparative proteomic analysis of differentially expressed proteins in Rhodococcus sp. BAP-1 induced by fluoranthene. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 169:282-291. [PMID: 30458394 DOI: 10.1016/j.ecoenv.2018.11.022] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 10/16/2018] [Accepted: 11/06/2018] [Indexed: 06/09/2023]
Abstract
To reveal the molecular mechanism at the level of regulation of proteins in Rhodococcus sp. BAP-1 induced by fluoranthene comparative proteomic analysis was performed on proteins extracted from fluoranthene-exposed cells on 1 d, 3 d, 6 d and 8 d compared with control cells using isobaric tags for relative and absolute quantization (iTRAQ) labeling and LC-MS/MS analysis to access differentially expressed proteins. As a result, we detected a total of 897 significantly differentially expressed proteins, including 30 shared proteins in four comparison clusters. We were able to short-list 190, 329, 101 and 90 proteins that were over-represented, and 394, 234, 65 and 49 under-represented proteins, in 1d/control, 3d/control, 6d/control and 8d/control comparisons, respectively. Functional analysis relied on Clusters of Orthologous Groups (COG), gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed that fluoranthene significantly altered the expression of proteins involved in metabolic and biosynthesis processes. Furthermore, BAP-1 up-regulates aldehyde dehydrogenase, cytochrome c oxidase, and oligopeptide transport ATP-binding protein, while down-regulates several other proteins in order to adapt to fluoranthene exposure. These findings provide important clues to reveal fluoranthene degradation mechanism in BAP-1 and promote its bioremediation applications.
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Affiliation(s)
- Hongqi Wang
- College of Water Sciences, Beijing Normal University, 100875 Beijing, China
| | - Yan Yang
- College of Water Sciences, Beijing Normal University, 100875 Beijing, China
| | - Jie Xu
- College of Water Sciences, Beijing Normal University, 100875 Beijing, China
| | - Dekang Kong
- College of Water Sciences, Beijing Normal University, 100875 Beijing, China
| | - Yi Li
- College of Environment and Resource, Guangxi Normal University, 541004 Guilin, Guangxi, China.
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25
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Green RT, East AK, Karunakaran R, Downie JA, Poole PS. Transcriptomic analysis of Rhizobium leguminosarum bacteroids in determinate and indeterminate nodules. Microb Genom 2019; 5:e000254. [PMID: 30777812 PMCID: PMC6421345 DOI: 10.1099/mgen.0.000254] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 01/15/2019] [Indexed: 01/25/2023] Open
Abstract
Two common classes of nitrogen-fixing legume root nodules are those that have determinate or indeterminate meristems, as in Phaseolus bean and pea, respectively. In indeterminate nodules, rhizobia terminally differentiate into bacteroids with endoreduplicated genomes, whereas bacteroids from determinate nodules are less differentiated and can regrow. We used RNA sequencing to compare bacteroid gene expression in determinate and indeterminate nodules using two Rhizobium leguminosarum strains whose genomes differ due to replacement of the symbiosis (Sym) plasmid pRP2 (strain Rlp4292) with pRL1 (strain RlvA34), thereby switching symbiosis hosts from Phaseolus bean (determinate nodules) to pea (indeterminate nodules). Both bacteroid types have gene expression patterns typical of a stringent response, a stressful environment and catabolism of dicarboxylates, formate, amino acids and quaternary amines. Gene expression patterns were indicative that bean bacteroids were more limited for phosphate, sulphate and iron than pea bacteroids. Bean bacteroids had higher levels of expression of genes whose products are predicted to be associated with metabolite detoxification or export. Pea bacteroids had increased expression of genes associated with DNA replication, membrane synthesis and the TCA (tricarboxylic acid) cycle. Analysis of bacteroid-specific transporter genes was indicative of distinct differences in sugars and other compounds in the two nodule environments. Cell division genes were down-regulated in pea but not bean bacteroids, while DNA synthesis was increased in pea bacteroids. This is consistent with endoreduplication of pea bacteroids and their failure to regrow once nodules senesce.
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Affiliation(s)
- R. T. Green
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - A. K. East
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
| | - R. Karunakaran
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - J. A. Downie
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
| | - P. S. Poole
- John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK
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Liang J, Hoffrichter A, Brachmann A, Marín M. Complete genome of Rhizobium leguminosarum Norway, an ineffective Lotus micro-symbiont. Stand Genomic Sci 2018; 13:36. [PMID: 30534351 PMCID: PMC6280393 DOI: 10.1186/s40793-018-0336-9] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 11/10/2018] [Indexed: 11/10/2022] Open
Abstract
Rhizobia bacteria engage in nitrogen-fixing root nodule symbiosis, a mutualistic interaction with legume plants in which a bidirectional nutrient exchange takes place. Occasionally, this interaction is suboptimal resulting in the formation of ineffective nodules in which little or no atmospheric nitrogen fixation occurs. Rhizobium leguminosarum Norway induces ineffective nodules in a wide range of Lotus hosts. To investigate the basis of this phenotype, we sequenced the complete genome of Rl Norway and compared it to the genome of the closely related strain R. leguminosarum bv. viciae 3841. The genome comprises 7,788,085 bp, distributed on a circular chromosome containing 63% of the genomic information and five large circular plasmids. The functionally classified bacterial gene set is distributed evenly among all replicons. All symbiotic genes (nod, fix, nif) are located on the pRLN3 plasmid. Whole genome comparisons revealed differences in the metabolic repertoire and in protein secretion systems, but not in classical symbiotic genes.
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Affiliation(s)
- Juan Liang
- Institute of Genetics, Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Anne Hoffrichter
- Institute of Genetics, Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Andreas Brachmann
- Institute of Genetics, Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Macarena Marín
- Institute of Genetics, Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
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Morrison KR, Ngo V, Cardullo RA, Reznick DN. How fish eggs are preadapted for the evolution of matrotrophy. Proc Biol Sci 2018; 284:rspb.2017.1342. [PMID: 29167357 DOI: 10.1098/rspb.2017.1342] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 10/19/2017] [Indexed: 11/12/2022] Open
Abstract
Teleost fishes evolved livebearing via egg retention 14 times. Matrotrophy has evolved within 12 of those lineages. By contrast, squamate reptiles evolved livebearing over 115 times, but only two to four of those lineages are known to have evolved matrotrophy. Is the discrepancy between these organisms in the probability of this transition caused by differences in their eggs? We show that the eggs of oviparous species in the superorder Atherinomorpha can acquire small organic molecules from their surrounding environment against a concentration gradient via mechanisms of active transport. Uptake rates were inhibited by competing radiolabelled amino acids against unlabelled versions of themselves. Transport was non-specific as uptake rates were similar for l-leucine and its biologically uncommon enantiomer d-leucine. Eggs are also capable of transporting larger microspheres across the membrane, but transport is inhibited at temperatures below 4°C, suggesting active transport occurs via pinocytosis. Conflict theory predicts that the ability of the egg to acquire maternal resources will facilitate the embryo-parent arms race that leads to the evolution of matrotrophy following the transition to livebearing. The shelled eggs of amniotes lack such access to maternal resources when retained in the evolution of viviparity.
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Affiliation(s)
- Keenan R Morrison
- Department of Biology, University of California, Riverside, CA 92507, USA
| | - Vyvian Ngo
- Department of Biology, University of California, Riverside, CA 92507, USA
| | - Richard A Cardullo
- Department of Biology, University of California, Riverside, CA 92507, USA
| | - David N Reznick
- Department of Biology, University of California, Riverside, CA 92507, USA
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28
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Beinart RA, Beaudoin DJ, Bernhard JM, Edgcomb VP. Insights into the metabolic functioning of a multipartner ciliate symbiosis from oxygen-depleted sediments. Mol Ecol 2018; 27:1794-1807. [PMID: 29271011 DOI: 10.1111/mec.14465] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2017] [Revised: 11/21/2017] [Accepted: 11/24/2017] [Indexed: 12/13/2022]
Abstract
Symbioses between anaerobic or microaerophilic protists and prokaryotes are common in anoxic and oxygen-depleted habitats ranging from marine sediments to gastrointestinal tracts. Nevertheless, little is known about the mechanisms of metabolic interaction between partners. In these putatively syntrophic associations, consumption of fermentative end products (e.g., hydrogen) by the prokaryotic symbionts is thought to facilitate protistan anaerobic metabolism. Here, we employed metagenomic and metatranscriptomic sequencing of a microaerophilic or anaerobic karyorelictid ciliate and its prokaryotic symbionts from oxygen-depleted Santa Barbara Basin (CA, USA) sediments to assess metabolic coupling within this consortium. This sequencing confirmed the predominance of deltaproteobacterial symbionts from the Families Desulfobacteraceae and Desulfobulbaceae and suggested active symbiont reduction of host-provided sulphate, transfer of small organic molecules from host to symbionts and hydrogen cycling among the symbionts. In addition, patterns of gene expression indicated active cell division by the symbionts, their growth via autotrophic processes and nitrogen exchange with the ciliate host. Altogether, this research underscores the importance of symbiont metabolism to host fermentative metabolism and, thus, likely its success in anoxic and low-oxygen habitats, but also suggests ciliate-associated prokaryotes play a role in important biogeochemical processes.
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Affiliation(s)
- R A Beinart
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - D J Beaudoin
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - J M Bernhard
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
| | - V P Edgcomb
- Department of Geology and Geophysics, Woods Hole Oceanographic Institution, Woods Hole, MA, USA
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29
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Moitinho-Silva L, Díez-Vives C, Batani G, Esteves AIS, Jahn MT, Thomas T. Integrated metabolism in sponge-microbe symbiosis revealed by genome-centered metatranscriptomics. THE ISME JOURNAL 2017; 11:1651-1666. [PMID: 28338677 PMCID: PMC5520145 DOI: 10.1038/ismej.2017.25] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2016] [Revised: 01/10/2017] [Accepted: 01/19/2017] [Indexed: 12/21/2022]
Abstract
Despite an increased understanding of functions in sponge microbiomes, the interactions among the symbionts and between symbionts and host are not well characterized. Here we reconstructed the metabolic interactions within the sponge Cymbastela concentrica microbiome in the context of functional features of symbiotic diatoms and the host. Three genome bins (CcPhy, CcNi and CcThau) were recovered from metagenomic data of C. concentrica, belonging to the proteobacterial family Phyllobacteriaceae, the Nitrospira genus and the thaumarchaeal order Nitrosopumilales. Gene expression was estimated by mapping C. concentrica metatranscriptomic reads. Our analyses indicated that CcPhy is heterotrophic, while CcNi and CcThau are chemolithoautotrophs. CcPhy expressed many transporters for the acquisition of dissolved organic compounds, likely available through the sponge's filtration activity and symbiotic carbon fixation. Coupled nitrification by CcThau and CcNi was reconstructed, supported by the observed close proximity of the cells in fluorescence in situ hybridization. CcPhy facultative anaerobic respiration and assimilation by diatoms may consume the resulting nitrate. Transcriptional analysis of diatom and sponge functions indicated that these organisms are likely sources of organic compounds, for example, creatine/creatinine and dissolved organic carbon, for other members of the symbiosis. Our results suggest that organic nitrogen compounds, for example, creatine, creatinine, urea and cyanate, fuel the nitrogen cycle within the sponge. This study provides an unprecedented view of the metabolic interactions within sponge-microbe symbiosis, bridging the gap between cell- and community-level knowledge.
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Affiliation(s)
- Lucas Moitinho-Silva
- Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | - Cristina Díez-Vives
- Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | - Giampiero Batani
- Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | - Ana IS Esteves
- Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, New South Wales, Australia
| | - Martin T Jahn
- Marine Microbiology, GEOMAR Helmholtz Centre for Ocean Research, Kiel, Germany
| | - Torsten Thomas
- Centre for Marine Bio-Innovation and School of Biological, Earth and Environmental Sciences, The University of New South Wales, Sydney, New South Wales, Australia
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Cheng G, Karunakaran R, East AK, Munoz-Azcarate O, Poole PS. Glutathione affects the transport activity of Rhizobium leguminosarum 3841 and is essential for efficient nodulation. FEMS Microbiol Lett 2017; 364:3045905. [PMID: 28333211 PMCID: PMC5407991 DOI: 10.1093/femsle/fnx045] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2016] [Accepted: 02/22/2017] [Indexed: 01/02/2023] Open
Abstract
As glutathione (GSH) plays an essential role in growth and symbiotic capacity of rhizobia, a glutathione synthetase (gshB) mutant of Rhizobium leguminosarum biovar viciae 3841 (Rlv3841) was characterised. It fails to efficiently utilise various compounds as a sole carbon source, including glucose, succinate, glutamine and histidine, and shows 60%-69% reduction in uptake rates of glucose, succinate and the non-metabolisable substrate α-amino isobutyric acid. The defect in glucose uptake can be overcome by addition of exogenous GSH, indicating GSH, but not its bacterial synthesis, is required for efficient transport. GSH is not involved in the regulation of the activity of Rlv3841's transporters via the global regulator of transport, PtsNTR. Although lack of GSH reduces transcription of the branched amino acid transporter, this was not the case for all uptake transport systems, for example, the amino acid permease. This suggests GSH alters activity and/or assembly of transport systems by an unknown mechanism. In interaction with plants, the gshB mutant is not only severely impaired in rhizosphere colonisation, but also shows a 50% reduction in dry weight of plants and nitrogen-fixation ability. This reveals that changes in GSH metabolism affect the bacterial-plant interactions required for symbiosis.
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Affiliation(s)
- Guojun Cheng
- College of Life Science, South-Central University for Nationalities, Wuhan 430074, China
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Ramakrishnan Karunakaran
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Alison K. East
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
- Department of Plant Sciences, University of Oxford, South Parks Road Oxford, OX1 3RB, UK
| | - Olaya Munoz-Azcarate
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
| | - Philip S. Poole
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH, UK
- Department of Plant Sciences, University of Oxford, South Parks Road Oxford, OX1 3RB, UK
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Xu J, Zhang L, Hou J, Wang X, Liu H, Zheng D, Liang R. iTRAQ-based quantitative proteomic analysis of the global response to 17β-estradiol in estrogen-degradation strain Pseudomonas putida SJTE-1. Sci Rep 2017; 7:41682. [PMID: 28155874 PMCID: PMC5290480 DOI: 10.1038/srep41682] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 12/23/2016] [Indexed: 11/28/2022] Open
Abstract
Microorganism degradation is efficient to remove the steroid hormones like 17β-estradiol (E2); but their degradation mechanism and metabolic network to these chemicals are still not very clear. Here the global responses of the estrogen-degradation strain Pseudomonas putida SJTE-1 to 17β-estradiol and glucose were analyzed and compared using the iTRAQ (isobaric tags for relative and absolute quantization) strategy combined with LC-MS/MS (liquid chromatography-tandem mass spectrometry). 78 proteins were identified with significant changes in expression; 45 proteins and 33 proteins were up-regulated and down-regulated, respectively. These proteins were mainly involved in the processes of stress response, energy metabolism, transportation, chemotaxis and cell motility, and carbon metabolism, considered probably responding to 17β-estradiol and playing a role in its metabolism. The up-regulated proteins in electron transfer, energy generation and transport systems were thought crucial for efficient uptake, translocation and transformation of 17β-estradiol. The over-expression of carbon metabolism proteins indicated cells may activate related pathway members to utilize 17β-estradiol. Meanwhile, proteins functioning in glucose capture and metabolism were mostly down-regulated. These findings provide important clues to reveal the 17β-estradiol degradation mechanism in P. putida and promote its bioremediation applications.
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Affiliation(s)
- Jing Xu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Lei Zhang
- School of Life Sciences, Fudan University, Shanghai 200433, China
| | - Jingli Hou
- Instrumental Analysis Center of Shanghai Jiaotong University, 800 Dong-Chuan Road, Shanghai 200240, China
| | - Xiuli Wang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Huan Liu
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Daning Zheng
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, China
| | - Rubing Liang
- State Key Laboratory of Microbial Metabolism, School of Life Sciences and Biotechnology, Shanghai Jiaotong University, 800 Dongchuan Road, Shanghai 200240, China
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McCraw SL, Park DH, Jones R, Bentley MA, Rico A, Ratcliffe RG, Kruger NJ, Collmer A, Preston GM. GABA (γ-Aminobutyric Acid) Uptake Via the GABA Permease GabP Represses Virulence Gene Expression in Pseudomonas syringae pv. tomato DC3000. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2016; 29:938-949. [PMID: 28001093 DOI: 10.1094/mpmi-08-16-0172-r] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The nonprotein amino acid γ-aminobutyric acid (GABA) is the most abundant amino acid in the tomato (Solanum lycopersicum) leaf apoplast and is synthesized by Arabidopsis thaliana in response to infection by the bacterial pathogen Pseudomonas syringae pv. tomato DC3000 (hereafter called DC3000). High levels of exogenous GABA have previously been shown to repress the expression of the type III secretion system (T3SS) in DC3000, resulting in reduced elicitation of the hypersensitive response (HR) in the nonhost plant tobacco (Nicotiana tabacum). This study demonstrates that the GABA permease GabP provides the primary mechanism for GABA uptake by DC3000 and that the gabP deletion mutant ΔgabP is insensitive to GABA-mediated repression of T3SS expression. ΔgabP displayed an enhanced ability to elicit the HR in young tobacco leaves and in tobacco plants engineered to produce increased levels of GABA, which supports the hypothesis that GABA uptake via GabP acts to regulate T3SS expression in planta. The observation that P. syringae can be rendered insensitive to GABA through loss of gabP but that gabP is retained by this bacterium suggests that GabP is important for DC3000 in a natural setting, either for nutrition or as a mechanism for regulating gene expression. [Formula: see text] Copyright © 2016 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .
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Affiliation(s)
- S L McCraw
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - D H Park
- 2 Department of Applied Biology, College of Agriculture and Life Sciences, Kangwon National University, Chuncheon 200-701, Republic of Korea
| | - R Jones
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - M A Bentley
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - A Rico
- 3 Departamento de Didáctica de la 9 Matemática y de las Ciencias Experimentales, Faculty of Education and Sport, University of the Basque Country UPV/EHU, Juan Ibañez de Sto. Domingo 1, 01006 Vitoria-Gasteiz, Spain; and
| | - R G Ratcliffe
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - N J Kruger
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
| | - A Collmer
- 4 School of Integrative Plant Science, Section of Plant Pathology and Plant-Microbe Biology, Cornell University, Ithaca, NY 14853, U.S.A
| | - G M Preston
- 1 Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, U.K
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Persson T, Van Nguyen T, Alloisio N, Pujic P, Berry AM, Normand P, Pawlowski K. The N-metabolites of roots and actinorhizal nodules from Alnus glutinosa and Datisca glomerata: can D. glomerata change N-transport forms when nodulated? Symbiosis 2016. [DOI: 10.1007/s13199-016-0407-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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34
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Nambu M, Tatsukami Y, Morisaka H, Kuroda K, Ueda M. Quantitative time-course proteome analysis of Mesorhizobium loti during nodule maturation. J Proteomics 2015; 125:112-20. [DOI: 10.1016/j.jprot.2015.04.034] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 04/22/2015] [Accepted: 04/27/2015] [Indexed: 11/30/2022]
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35
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Peng J, Hao B, Liu L, Wang S, Ma B, Yang Y, Xie F, Li Y. RNA-Seq and microarrays analyses reveal global differential transcriptomes of Mesorhizobium huakuii 7653R between bacteroids and free-living cells. PLoS One 2014; 9:e93626. [PMID: 24695521 PMCID: PMC3973600 DOI: 10.1371/journal.pone.0093626] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 03/04/2014] [Indexed: 11/18/2022] Open
Abstract
Mesorhizobium huakuii 7653R occurs either in nitrogen-fixing symbiosis with its host plant, Astragalus sinicus, or free-living in the soil. The M. huakuii 7653R genome has recently been sequenced. To better understand the complex biochemical and developmental changes that occur in 7653R during bacteroid development, RNA-Seq and Microarrays were used to investigate the differential transcriptomes of 7653R bacteroids and free-living cells. The two approaches identified several thousand differentially expressed genes. The most prominent up-regulation occurred in the symbiosis plasmids, meanwhile gene expression is concentrated to a set of genes (clusters) in bacteroids to fulfill corresponding functional requirements. The results suggested that the main energy metabolism is active while fatty acid metabolism is inactive in bacteroid and that most of genes relevant to cell cycle are down-regulated accordingly. For a global analysis, we reconstructed a protein-protein interaction (PPI) network for 7653R and integrated gene expression data into the network using Cytoscape. A highly inter-connected subnetwork, with function enrichment for nitrogen fixation, was found, and a set of hubs and previously uncharacterized genes participating in nitrogen fixation were identified. The results described here provide a broader biological landscape and novel insights that elucidate rhizobial bacteroid differentiation, nitrogen fixation and related novel gene functions.
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Affiliation(s)
- Jieli Peng
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Baohai Hao
- Center for Bioinformatics, School of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Liu Liu
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Shanming Wang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Binguang Ma
- Center for Bioinformatics, School of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Yi Yang
- Center for Bioinformatics, School of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Fuli Xie
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
| | - Youguo Li
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, Hubei, P. R. China
- * E-mail:
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Abstract
Rhizobia are bacteria in the α-proteobacterial genera Rhizobium, Sinorhizobium, Mesorhizobium, Azorhizobium and Bradyrhizobium that reduce (fix) atmospheric nitrogen in symbiotic association with a compatible host plant. In free-living and/or symbiotically associated rhizobia, amino acids may, in addition to their incorporation into proteins, serve as carbon, nitrogen or sulfur sources, signals of cellular nitrogen status and precursors of important metabolites. Depending on the rhizobia-host plant combination, microsymbiont amino acid metabolism (biosynthesis, transport and/or degradation) is often crucial to the establishment and maintenance of an effective nitrogen-fixing symbiosis and is intimately interconnected with the metabolism of the plant. This review summarizes past findings and current research directions in rhizobial amino acid metabolism and evaluates the genetic, biochemical and genome expression studies from which these are derived. Specific sections deal with the regulation of rhizobial amino acid metabolism, amino acid transport, and finally the symbiotic roles of individual amino acids in different plant-rhizobia combinations.
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Characterization and molecular mechanism of AroP as an aromatic amino acid and histidine transporter in Corynebacterium glutamicum. J Bacteriol 2013; 195:5334-42. [PMID: 24056108 DOI: 10.1128/jb.00971-13] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Corynebacterium glutamicum is equipped with abundant membrane transporters to adapt to a changing environment. Many amino acid transporters have been identified in C. glutamicum, but histidine uptake has not been investigated in detail. Here, we identified the aromatic amino acid transporter encoded by aroP as a histidine transporter in C. glutamicum by a combination of the growth and histidine uptake features. Characterization of histidine uptake showed that AroP has a moderate affinity for histidine, with a Km value of 11.40 ± 2.03 μM, and histidine uptake by AroP is competitively inhibited by the aromatic amino acids. Among the four substrates, AroP exhibits a stronger preference for tryptophan than for tyrosine, phenylalanine, and histidine. Homology structure modeling and molecular docking were performed to predict the substrate binding modes and conformational changes during substrate transport. These results suggested that tryptophan is best accommodated in the binding pocket due to shape compatibility, strong hydrophobic interactions, and the lowest binding energy, which is consistent with the observed substrate preference of AroP. Furthermore, the missense mutations of the putative substrate binding sites verified that Ser24, Ala28, and Gly29 play crucial roles in substrate binding and are highly conserved in the Gram-positive bacteria. Finally, the expression of aroP is not significantly affected by extracellular histidine or aromatic amino acids, indicating that the physiological role of AroP may be correlated with the increased fitness of C. glutamicum to assimilate extracellular amino acid for avoiding the high energy cost of amino acid biosynthesis.
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Untiet V, Karunakaran R, Krämer M, Poole P, Priefer U, Prell J. ABC transport is inactivated by the PTS(Ntr) under potassium limitation in Rhizobium leguminosarum 3841. PLoS One 2013; 8:e64682. [PMID: 23724079 PMCID: PMC3665714 DOI: 10.1371/journal.pone.0064682] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 04/17/2013] [Indexed: 11/29/2022] Open
Abstract
PTSNtr is a regulatory phosphotransferase system in many bacteria. Mutation of the PTSNtr enzymes causes pleiotropic growth phenotypes, dry colony morphology and a posttranslational inactivation of ABC transporters in Rhizobium leguminosarum 3841. The PTSNtr proteins EINtr and 2 copies of EIIANtr have been described previously. Here we identify the intermediate phosphocarrier protein NPr and show its phosphorylation by EINtrin vitro. Furthermore we demonstrate that phosphorylation of EINtr and NPr is required for ABC transport activation and that the N-terminal GAF domain of EINtr is not required for autophosphorylation. Previous studies have shown that non-phosphorylated EIIANtr is able to modulate the transcriptional activation of the high affinity potassium transporter KdpABC. In R. leguminosarum 3841 kdpABC expression strictly depends on EIIANtr. Here we demonstrate that under strong potassium limitation ABC transport is inactivated, presumably by non-phosphorylated EIIANtr. This is to our knowledge the first report where PTSNtr dictates an essential cellular function. This is achieved by the inverse regulation of two important ATP dependent transporter classes.
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Affiliation(s)
| | | | | | - Philip Poole
- Molecular Microbiology, John Innes Centre, Norwich, United Kingdom
| | | | - Jürgen Prell
- Soil Ecology, RWTH Aachen, Aachen, Germany
- * E-mail:
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Ormeño-Orrillo E, Martínez-Romero E. Phenotypic tests in Rhizobium species description: An opinion and (a sympatric speciation) hypothesis. Syst Appl Microbiol 2013; 36:145-7. [DOI: 10.1016/j.syapm.2012.11.009] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/23/2012] [Accepted: 11/27/2012] [Indexed: 10/27/2022]
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40
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Yurgel SN, Rice J, Kahn ML. Transcriptome analysis of the role of GlnD/GlnBK in nitrogen stress adaptation by Sinorhizobium meliloti Rm1021. PLoS One 2013; 8:e58028. [PMID: 23516427 PMCID: PMC3596328 DOI: 10.1371/journal.pone.0058028] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Accepted: 01/30/2013] [Indexed: 11/19/2022] Open
Abstract
Transcriptional changes in the nitrogen stress response (NSR) of wild type S. meliloti Rm1021, and isogenic strains missing both PII proteins, GlnB and GlnK, or carrying a ΔglnD-sm2 mutation were analyzed using whole-genome microarrays. This approach allowed us to identify a number of new genes involved in the NSR and showed that the response of these bacteria to nitrogen stress overlaps with other stress responses, including induction of the fixK2 transcriptional activator and genes that are part of the phosphate stress response. Our data also show that GlnD and GlnBK proteins may regulate many genes that are not part of the NSR. Analysis of transcriptome profiles of the Rm1021 ΔglnD-sm2 strain allowed us to identify several genes that appear to be regulated by GlnD without the participation of the PII proteins.
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Affiliation(s)
- Svetlana N Yurgel
- Institute of Biological Chemistry, Washington State University, Pullman, Washington, USA.
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41
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Badri DV, Chaparro JM, Zhang R, Shen Q, Vivanco JM. Application of natural blends of phytochemicals derived from the root exudates of Arabidopsis to the soil reveal that phenolic-related compounds predominantly modulate the soil microbiome. J Biol Chem 2013; 288:4502-12. [PMID: 23293028 DOI: 10.1074/jbc.m112.433300] [Citation(s) in RCA: 248] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The roots of plants have the ability to influence its surrounding microbiology, the so-called rhizosphere microbiome, through the creation of specific chemical niches in the soil mediated by the release of phytochemicals. Here we report how these phytochemicals could modulate the microbial composition of a soil in the absence of the plant. For this purpose, root exudates of Arabidopsis were collected and fractionated to obtain natural blends of phytochemicals at various relative concentrations that were characterized by GC-MS and applied repeatedly to a soil. Soil bacterial changes were monitored by amplifying and pyrosequencing the 16 S ribosomal small subunit region. Our analyses reveal that one phytochemical can culture different operational taxonomic units (OTUs), mixtures of phytochemicals synergistically culture groups of OTUs, and the same phytochemical can act as a stimulator or deterrent to different groups of OTUs. Furthermore, phenolic-related compounds showed positive correlation with a higher number of unique OTUs compared with other groups of compounds (i.e. sugars, sugar alcohols, and amino acids). For instance, salicylic acid showed positive correlations with species of Corynebacterineae, Pseudonocardineae and Streptomycineae, and GABA correlated with species of Sphingomonas, Methylobacterium, Frankineae, Variovorax, Micromonosporineae, and Skermanella. These results imply that phenolic compounds act as specific substrates or signaling molecules for a large group of microbial species in the soil.
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Affiliation(s)
- Dayakar V Badri
- Department of Horticulture and Landscape Architecture and Center for Rhizosphere Biology, Colorado State University, Fort Collins, Colorado 80523, USA
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42
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Abstract
Symbiotic nitrogen fixation by rhizobia in legume root nodules injects approximately 40 million tonnes of nitrogen into agricultural systems each year. In exchange for reduced nitrogen from the bacteria, the plant provides rhizobia with reduced carbon and all the essential nutrients required for bacterial metabolism. Symbiotic nitrogen fixation requires exquisite integration of plant and bacterial metabolism. Central to this integration are transporters of both the plant and the rhizobia, which transfer elements and compounds across various plant membranes and the two bacterial membranes. Here we review current knowledge of legume and rhizobial transport and metabolism as they relate to symbiotic nitrogen fixation. Although all legume-rhizobia symbioses have many metabolic features in common, there are also interesting differences between them, which show that evolution has solved metabolic problems in different ways to achieve effective symbiosis in different systems.
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Affiliation(s)
- Michael Udvardi
- Plant Biology Division, Samuel Roberts Noble Foundation, Ardmore, OK 73401, USA.
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Planamente S, Mondy S, Hommais F, Vigouroux A, Moréra S, Faure D. Structural basis for selective GABA binding in bacterial pathogens. Mol Microbiol 2012; 86:1085-99. [PMID: 23043322 DOI: 10.1111/mmi.12043] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/14/2012] [Indexed: 11/27/2022]
Abstract
GABA acts as an intercellular signal in eukaryotes and as an interspecies signal in host-microbe interactions. Structural characteristics of selective eukaryotic GABA receptors and bacterial GABA sensors are unknown. Here, we identified the selective GABA-binding protein, called Atu4243, in the plant pathogen Agrobacterium tumefaciens. A constructed atu4243 mutant was affected in GABA transport and in expression of the GABA-regulated functions, including aggressiveness on two plant hosts and degradation of the quorum-sensing signal. The GABA-bound Atu4243 structure at 1.28 Å reveals that GABA adopts a conformation never observed so far and interacts with two key residues, Arg(203) and Asp(226) of which the role in GABA binding and GABA signalling in Agrobacterium has been validated using appropriate mutants. The conformational GABA-analogue trans-4-aminocrotonic acid (TACA) antagonizes GABA activity, suggesting structural similarities between the binding sites of the bacterial sensor Atu4243 and mammalian GABA(C) receptors. Exploration of genomic databases reveals Atu4243 orthologues in several pathogenic and symbiotic proteobacteria, such as Rhizobium, Azospirillum, Burkholderia and Pseudomonas. Thus, this study establishes a structural basis for selective GABA sensors and offers opportunities for deciphering the role of the GABA-mediated communication in several host-pathogen interactions.
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Affiliation(s)
- Sara Planamente
- Institut des Sciences du Végétal, CNRS, avenue de la terrasse, 91198, Gif-sur-Yvette, France
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Terpolilli JJ, Hood GA, Poole PS. What determines the efficiency of N(2)-fixing Rhizobium-legume symbioses? Adv Microb Physiol 2012; 60:325-89. [PMID: 22633062 DOI: 10.1016/b978-0-12-398264-3.00005-x] [Citation(s) in RCA: 88] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Biological nitrogen fixation is vital to nutrient cycling in the biosphere and is the major route by which atmospheric dinitrogen (N(2)) is reduced to ammonia. The largest single contribution to biological N(2) fixation is carried out by rhizobia, which include a large group of both alpha and beta-proteobacteria, almost exclusively in association with legumes. Rhizobia must compete to infect roots of legumes and initiate a signaling dialog with host plants that leads to nodule formation. The most common form of infection involves the growth of rhizobia down infection threads which are laid down by the host plant. Legumes form either indeterminate or determinate types of nodules, with these groups differing widely in nodule morphology and often in the developmental program by which rhizobia form N(2) fixing bacteroids. In particular, indeterminate legumes from the inverted repeat-lacking clade (IRLC) (e.g., peas, vetch, alfalfa, medics) produce a cocktail of antimicrobial peptides which cause endoreduplication of the bacterial genome and force rhizobia into a nongrowing state. Bacteroids often become dependent on the plant for provision of key cofactors, such as homocitrate needed for nitrogenase activity or for branched chain amino acids. This has led to the suggestion that bacteroids at least from the IRLC can be considered as ammoniaplasts, where they are effectively facultative plant organelles. A low O(2) tension is critical both to induction of genes needed for N(2) fixation and to the subsequent exchange of nutrient between plants and bacteroids. To achieve high rates of N(2) fixation, the legume host and Rhizobium must be closely matched not only for infection, but for optimum development, nutrient exchange, and N(2) fixation. In this review, we consider the multiple steps of selection and bacteroid development and how these alter the overall efficiency of N(2) fixation.
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Affiliation(s)
- Jason J Terpolilli
- Department of Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich, UK
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Sulieman S, Tran LSP. Asparagine: an amide of particular distinction in the regulation of symbiotic nitrogen fixation of legumes. Crit Rev Biotechnol 2012; 33:309-27. [DOI: 10.3109/07388551.2012.695770] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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46
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Prell J, Mulley G, Haufe F, White JP, Williams A, Karunakaran R, Downie JA, Poole PS. The PTS(Ntr) system globally regulates ATP-dependent transporters in Rhizobium leguminosarum. Mol Microbiol 2012; 84:117-29. [PMID: 22340847 DOI: 10.1111/j.1365-2958.2012.08014.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Mutation of ptsP encoding EI(Ntr) of the PTS(Ntr) system in Rhizobium leguminosarum strain Rlv3841 caused a pleiotropic phenotype as observed with many bacteria. The mutant formed dry colonies and grew poorly on organic nitrogen or dicarboxylates. Most strikingly the ptsP mutant had low activity of a broad range of ATP-dependent ABC transporters. This lack of activation, which occurred post-translationally, may explain many of the pleiotropic effects. In contrast proton-coupled transport systems were not inhibited in a ptsP mutant. Regulation by PtsP also involves two copies of ptsN that code for EIIA(Ntr) , resulting in a phosphorylation cascade. As in Escherichia coli, the Rlv3841 PTS(Ntr) system also regulates K(+) homeostasis by transcriptional activation of the high-affinity ATP-dependent K(+) transporter KdpABC. This involves direct interaction of a two-component sensor regulator pair KdpDE with unphosphorylated EIIA(Ntr) . Critically, ptsP mutants, which cannot phosphorylate PtsN1 or PtsN2, had a fully activated KdpABC transporter. This is the opposite pattern from that observed with ABC transporters which apparently require phosphorylation of PtsN. These results suggest that ATP-dependent transport might be regulated via PTS(Ntr) responding to the cellular energy charge. ABC transport may be inactivated at low energy charge, conserving ATP for essential processes including K(+) homeostasis.
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Affiliation(s)
- J Prell
- Molecular Microbiology, John Innes Centre, Norwich Research Park, Norwich NR4 7UH, UK
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Taté R, Cermola M, Riccio A, Diez-Roux G, Patriarca EJ. Glutathione is required by Rhizobium etli for glutamine utilization and symbiotic effectiveness. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:331-40. [PMID: 22007600 DOI: 10.1094/mpmi-06-11-0163] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Here, we provide genetic and biochemical evidence indicating that the ability of Rhizobium etli bacteria to efficiently catabolize glutamine depends on its ability to produce reduced glutathione (l-γ-glutamyl-l-cysteinylglycine [GSH]). We find that GSH-deficient strains, namely a gshB (GSH synthetase) and a gor (GSH reductase) mutant, can use different amino acids, including histidine, alanine, and asparagine but not glutamine, as sole source of carbon, energy, and nitrogen. Moreover, l-buthionine(S,R)-sulfoximine, a GSH synthesis inhibitor, or diamide that oxidizes GSH, induced the same phenotype in the wild-type strain. Among the steps required for its utilization, glutamine uptake, occurring through the two well-characterized carriers (Aap and Bra systems) but not glutamine degradation or respiration, was largely reduced in GSH-deficient strains. Furthermore, GSH-deficient mutants of R. etli showed a reduced symbiotic efficiency. Exogenous GSH was sufficient to rescue glutamine uptake or degradation ability, as well as the symbiotic effectiveness of GSH mutants. Our results suggest a previously unknown GSH-glutamine metabolic relationship in bacteria.
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Affiliation(s)
- Rosarita Taté
- Institute Of Genetics And Biophysics, A Buzzati-Traverso, CNR, Naples, Italy
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Identification and characterization of γ-aminobutyric acid uptake system GabPCg (NCgl0464) in Corynebacterium glutamicum. Appl Environ Microbiol 2012; 78:2596-601. [PMID: 22307305 DOI: 10.1128/aem.07406-11] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Corynebacterium glutamicum is widely used for industrial production of various amino acids and vitamins, and there is growing interest in engineering this bacterium for more commercial bioproducts such as γ-aminobutyric acid (GABA). In this study, a C. glutamicum GABA-specific transporter (GabP(Cg)) encoded by ncgl0464 was identified and characterized. GabP(Cg) plays a major role in GABA uptake and is essential to C. glutamicum growing on GABA. GABA uptake by GabP(Cg) was weakly competed by l-Asn and l-Gln and stimulated by sodium ion (Na(+)). The K(m) and V(max) values were determined to be 41.1 ± 4.5 μM and 36.8 ± 2.6 nmol min(-1) (mg dry weight [DW])(-1), respectively, at pH 6.5 and 34.2 ± 1.1 μM and 67.3 ± 1.0 nmol min(-1) (mg DW)(-1), respectively, at pH 7.5. GabP(Cg) has 29% amino acid sequence identity to a previously and functionally identified aromatic amino acid transporter (TyrP) of Escherichia coli but low identities to the currently known GABA transporters (17% and 15% to E. coli GabP and Bacillus subtilis GabP, respectively). The mutant RES167 Δncgl0464/pGXKZ9 with the GabP(Cg) deletion showed 12.5% higher productivity of GABA than RES167/pGXKZ9. It is concluded that GabP(Cg) represents a new type of GABA transporter and is potentially important for engineering GABA-producing C. glutamicum strains.
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Analysis of the LIV system of Campylobacter jejuni reveals alternative roles for LivJ and LivK in commensalism beyond branched-chain amino acid transport. J Bacteriol 2011; 193:6233-43. [PMID: 21949065 DOI: 10.1128/jb.05473-11] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Campylobacter jejuni is a leading cause of diarrheal disease in humans and an intestinal commensal in poultry and other agriculturally important animals. These zoonotic infections result in significant amounts of C. jejuni present in the food supply to contribute to disease in humans. We previously found that a transposon insertion in Cjj81176_1038, encoding a homolog of the Escherichia coli LivJ periplasmic binding protein of the leucine, isoleucine, and valine (LIV) branched-chain amino acid transport system, reduced the commensal colonization capacity of C. jejuni 81-176 in chicks. Cjj81176_1038 is the first gene of a six-gene locus that encodes homologous components of the E. coli LIV system. By analyzing mutants with in-frame deletions of individual genes or pairs of genes, we found that this system constitutes a LIV transport system in C. jejuni responsible for a high level of leucine acquisition and, to a lesser extent, isoleucine and valine acquisition. Despite each LIV protein being required for branched-chain amino acid transport, only the LivJ and LivK periplasmic binding proteins were required for wild-type levels of commensal colonization of chicks. All LIV permease and ATPase components were dispensable for in vivo growth. These results suggest that the biological functions of LivJ and LivK for colonization are more complex than previously hypothesized and extend beyond a role for binding and acquiring branched-chain amino acids during commensalism. In contrast to other studies indicating a requirement and utilization of other specific amino acids for colonization, acquisition of branched-chain amino acids does not appear to be a determinant for C. jejuni during commensalism.
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Oldroyd GED, Murray JD, Poole PS, Downie JA. The rules of engagement in the legume-rhizobial symbiosis. Annu Rev Genet 2011; 45:119-44. [PMID: 21838550 DOI: 10.1146/annurev-genet-110410-132549] [Citation(s) in RCA: 646] [Impact Index Per Article: 49.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Rhizobial bacteria enter a symbiotic association with leguminous plants, resulting in differentiated bacteria enclosed in intracellular compartments called symbiosomes within nodules on the root. The nodules and associated symbiosomes are structured for efficient nitrogen fixation. Although the interaction is beneficial to both partners, it comes with rigid rules that are strictly enforced by the plant. Entry into root cells requires appropriate recognition of the rhizobial Nod factor signaling molecule, and this recognition activates a series of events, including polarized root-hair tip growth, invagination associated with bacterial infection, and the promotion of cell division in the cortex leading to the nodule meristem. The plant's command of the infection process has been highlighted by its enforcement of terminal differentiation upon the bacteria within nodules of some legumes, and this can result in a loss of bacterial viability while permitting effective nitrogen fixation. Here, we review the mechanisms by which the plant allows bacterial infection and promotes the formation of the nodule, as well as the details of how this intimate association plays out inside the cells of the nodule where a complex interchange of metabolites and regulatory peptides force the bacteria into a nitrogen-fixing organelle-like state.
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Affiliation(s)
- Giles E D Oldroyd
- John Innes Center, Norwich Research Park, Norwich NR4 7UH, United Kingdom.
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