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Wójcik M, Koper P, Żebracki K, Marczak M, Mazur A. Genomic and Metabolic Characterization of Plant Growth-Promoting Rhizobacteria Isolated from Nodules of Clovers Grown in Non-Farmed Soil. Int J Mol Sci 2023; 24:16679. [PMID: 38069003 PMCID: PMC10706249 DOI: 10.3390/ijms242316679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/18/2023] Open
Abstract
The rhizosphere microbiota, which includes plant growth-promoting rhizobacteria (PGPR), is essential for nutrient acquisition, protection against pathogens, and abiotic stress tolerance in plants. However, agricultural practices affect the composition and functions of microbiota, reducing their beneficial effects on plant growth and health. Among PGPR, rhizobia form mutually beneficial symbiosis with legumes. In this study, we characterized 16 clover nodule isolates from non-farmed soil to explore their plant growth-promoting (PGP) potential, hypothesizing that these bacteria may possess unique, unaltered PGP traits, compared to those affected by common agricultural practices. Biolog profiling revealed their versatile metabolic capabilities, enabling them to utilize a wide range of carbon and energy sources. All isolates were effective phosphate solubilizers, and individual strains exhibited 1-aminocyclopropane-1-carboxylate deaminase and metal ion chelation activities. Metabolically active strains showed improved performance in symbiotic interactions with plants. Comparative genomics revealed that the genomes of five nodule isolates contained a significantly enriched fraction of unique genes associated with quorum sensing and aromatic compound degradation. As the potential of PGPR in agriculture grows, we emphasize the importance of the molecular and metabolic characterization of PGP traits as a fundamental step towards their subsequent application in the field as an alternative to chemical fertilizers and supplements.
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Affiliation(s)
| | | | | | | | - Andrzej Mazur
- Department of Genetics and Microbiology, Institute of Biological Sciences, Maria Curie-Skłodowska University, Akademicka 19 St., 20-033 Lublin, Poland; (M.W.); (P.K.); (K.Ż.); (M.M.)
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Sorty AM, Ntana F, Hansen M, Stougaard P. Plant-Root Exudate Analogues Influence Activity of the 1-Aminocyclopropane-1-Carboxylate (ACC) Deaminase Gene in Pseudomonas hormoni G20-18 T. Microorganisms 2023; 11:2504. [PMID: 37894162 PMCID: PMC10608949 DOI: 10.3390/microorganisms11102504] [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: 08/23/2023] [Revised: 09/27/2023] [Accepted: 09/28/2023] [Indexed: 10/29/2023] Open
Abstract
Plants exposed to abiotic stress such as drought and salinity produce 1-aminocyclopropane-1-carboxylic acid (ACC) that is converted into the stress hormone ethylene. However, plant growth-promoting bacteria (PGPB), which synthesize the enzyme ACC deaminase, may lower the ACC concentration thereby reducing the concentration of ethylene and alleviating the abiotic stress. The PGPB Pseudomonas hormoni G20-18T (previously named P. fluorescens G20-18) harbors the genes acdR and acdS that encode regulation and synthesis of ACC deaminase, respectively. Regulation of the acdS gene has been investigated in several studies, but so far, it has been an open question whether plants can regulate microbial synthesis of ACC deaminase. In this study, small molecules in wheat root exudates were identified using untargeted metabolomics, and compounds belonging to amino acids, organic acids, and sugars were selected for evaluation of their influence on the expression of the acdS and acdR genes in P. hormoni G20-18T. acdS and acdR promoters were fused to the fluorescence reporter gene mCherry enabling the study of acdS and acdR promoter activity. In planta studies in wheat seedlings indicated an induced expression of acdS in association with the roots. Exudate molecules such as aspartate, alanine, arginine, and fumarate as well as glucose, fructose, and mannitol actively induced the acdS promoter, whereas the plant hormone indole-3-acetic acid (IAA) inhibited expression. Here, we present a model for how stimulatory and inhibitory root exudate molecules influence acdS promoter activity in P. hormoni G20-18T.
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Affiliation(s)
- Ajay Madhusudan Sorty
- Department of Environmental Science, Aarhus University, 4000 Roskilde, Denmark; (F.N.); (M.H.)
| | | | | | - Peter Stougaard
- Department of Environmental Science, Aarhus University, 4000 Roskilde, Denmark; (F.N.); (M.H.)
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Singh A, Kumar M, Chakdar H, Pandiyan K, Kumar SC, Zeyad MT, Singh BN, Ravikiran KT, Mahto A, Srivastava AK, Saxena AK. Influence of host genotype in establishing root associated microbiome of indica rice cultivars for plant growth promotion. Front Microbiol 2022; 13:1033158. [PMID: 36452918 PMCID: PMC9702084 DOI: 10.3389/fmicb.2022.1033158] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 10/20/2022] [Indexed: 08/29/2023] Open
Abstract
Rice plants display a unique root ecosystem comprising oxic-anoxic zones, harboring a plethora of metabolic interactions mediated by its root microbiome. Since agricultural land is limited, an increase in rice production will rely on novel methods of yield enhancement. The nascent concept of tailoring plant phenotype through the intervention of synthetic microbial communities (SynComs) is inspired by the genetics and ecology of core rhizobiome. In this direction, we have studied structural and functional variations in the root microbiome of 10 indica rice varieties. The studies on α and β-diversity indices of rhizospheric root microbiome with the host genotypes revealed variations in the structuring of root microbiome as well as a strong association with the host genotypes. Biomarker discovery, using machine learning, highlighted members of class Anaerolineae, α-Proteobacteria, and bacterial genera like Desulfobacteria, Ca. Entotheonella, Algoriphagus, etc. as the most important features of indica rice microbiota having a role in improving the plant's fitness. Metabolically, rice rhizobiomes showed an abundance of genes related to sulfur oxidation and reduction, biofilm production, nitrogen fixation, denitrification, and phosphorus metabolism. This comparative study of rhizobiomes has outlined the taxonomic composition and functional diversification of rice rhizobiome, laying the foundation for the development of next-generation microbiome-based technologies for yield enhancement in rice and other crops.
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Affiliation(s)
- Arjun Singh
- ICAR-National Bureau of Agriculturally Important Microorganisms, Mau, India
- ICAR-Central Soil Salinity Research Institute, RRS, Lucknow, India
| | - Murugan Kumar
- ICAR-National Bureau of Agriculturally Important Microorganisms, Mau, India
| | - Hillol Chakdar
- ICAR-National Bureau of Agriculturally Important Microorganisms, Mau, India
| | - Kuppusamy Pandiyan
- ICAR-National Bureau of Agriculturally Important Microorganisms, Mau, India
- Ginning Training Center, ICAR-Central Institute for Research on Cotton Technology, Nagpur, India
| | - Shiv Charan Kumar
- ICAR-National Bureau of Agriculturally Important Microorganisms, Mau, India
| | | | | | - K. T. Ravikiran
- ICAR-Central Soil Salinity Research Institute, RRS, Lucknow, India
| | - Arunima Mahto
- National Institute of Plant Genome Research, New Delhi, India
| | | | - Anil Kumar Saxena
- ICAR-National Bureau of Agriculturally Important Microorganisms, Mau, India
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4
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Cangioli L, Vaccaro F, Fini M, Mengoni A, Fagorzi C. Scent of a Symbiont: The Personalized Genetic Relationships of Rhizobium-Plant Interaction. Int J Mol Sci 2022; 23:3358. [PMID: 35328782 PMCID: PMC8954435 DOI: 10.3390/ijms23063358] [Citation(s) in RCA: 2] [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: 02/25/2022] [Revised: 03/17/2022] [Accepted: 03/18/2022] [Indexed: 01/24/2023] Open
Abstract
Many molecular signals are exchanged between rhizobia and host legume plants, some of which are crucial for symbiosis to take place, while others are modifiers of the interaction, which have great importance in the competition with the soil microbiota and in the genotype-specific perception of host plants. Here, we review recent findings on strain-specific and host genotype-specific interactions between rhizobia and legumes, discussing the molecular actors (genes, gene products and metabolites) which play a role in the establishment of symbiosis, and highlighting the need for research including the other components of the soil (micro)biota, which could be crucial in developing rational-based strategies for bioinoculants and synthetic communities' assemblage.
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Affiliation(s)
- Lisa Cangioli
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Francesca Vaccaro
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Margherita Fini
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Alessio Mengoni
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
| | - Camilla Fagorzi
- Department of Biology, University of Florence, Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
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Katiyar P, Kumar S, Arora NK. Interactions of Nitrogen-Fixing Bacteria and Cereal Crops: An Important Dimension. NITROGEN FIXING BACTERIA: SUSTAINABLE GROWTH OF NON-LEGUMES 2022:169-194. [DOI: 10.1007/978-981-19-4906-7_8] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/26/2024]
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Ku YS, Wang Z, Duan S, Lam HM. Rhizospheric Communication through Mobile Genetic Element Transfers for the Regulation of Microbe-Plant Interactions. BIOLOGY 2021; 10:biology10060477. [PMID: 34071379 PMCID: PMC8227670 DOI: 10.3390/biology10060477] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 05/24/2021] [Accepted: 05/24/2021] [Indexed: 12/25/2022]
Abstract
Simple Summary Rhizosphere, where microbes and plants coexist, is a hotspot of mobile genetic element (MGE) transfers. It was suggested that ancient MGE transfers drove the evolution of both microbes and plants. On the other hand, recurrent MGE transfers regulate microbe-plant interaction and the adaptation of microbes and plants to the environment. The studies of MGE transfers in the rhizosphere provide useful information for the research on pathogenic/ beneficial microbe-plant interaction. In addition, MGE transfers between microbes and the influence by plant root exudates on such transfers provide useful information for the research on bioremediation. Abstract The transfer of mobile genetic elements (MGEs) has been known as a strategy adopted by organisms for survival and adaptation to the environment. The rhizosphere, where microbes and plants coexist, is a hotspot of MGE transfers. In this review, we discuss the classic mechanisms as well as novel mechanisms of MGE transfers in the rhizosphere. Both intra-kingdom and cross-kingdom MGE transfers will be addressed. MGE transfers could be ancient events which drove evolution or recurrent events which regulate adaptations. Recent findings on MGE transfers between plant and its interacting microbes suggest gene regulations brought forth by such transfers for symbiosis or defense mechanisms. In the natural environment, factors such as temperature and soil composition constantly influence the interactions among different parties in the rhizosphere. In this review, we will also address the effects of various environmental factors on MGE transfers in the rhizosphere. Besides environmental factors, plant root exudates also play a role in the regulation of MGE transfer among microbes in the rhizosphere. The potential use of microbes and plants for bioremediation will be discussed.
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Fagorzi C, Bacci G, Huang R, Cangioli L, Checcucci A, Fini M, Perrin E, Natali C, diCenzo GC, Mengoni A. Nonadditive Transcriptomic Signatures of Genotype-by-Genotype Interactions during the Initiation of Plant-Rhizobium Symbiosis. mSystems 2021. [PMID: 33436514 DOI: 10.1101/2020.06.15.152710] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023] Open
Abstract
Rhizobia are ecologically important, facultative plant-symbiotic microbes. In nature, there is a large variability in the association of rhizobial strains and host plants of the same species. Here, we evaluated whether plant and rhizobial genotypes influence the initial transcriptional response of rhizobium following perception of a host plant. RNA sequencing of the model rhizobium Sinorhizobium meliloti exposed to root exudates or luteolin (an inducer of nod genes, involved in the early steps of symbiotic interaction) was performed on a combination of three S. meliloti strains and three alfalfa varieties as host plants. The response to root exudates involved hundreds of changes in the rhizobium transcriptome. Of the differentially expressed genes, 35% were influenced by the strain genotype, 16% were influenced by the plant genotype, and 29% were influenced by strain-by-host plant genotype interactions. We also examined the response of a hybrid S. meliloti strain in which the symbiotic megaplasmid (∼20% of the genome) was mobilized between two of the above-mentioned strains. Dozens of genes were upregulated in the hybrid strain, indicative of nonadditive variation in the transcriptome. In conclusion, this study demonstrated that transcriptional responses of rhizobia upon perception of legumes are influenced by the genotypes of both symbiotic partners and their interaction, suggesting a wide spectrum of genetic determinants involved in the phenotypic variation of plant-rhizobium symbiosis.IMPORTANCE A sustainable way for meeting the need of an increased global food demand should be based on a holobiont perspective, viewing crop plants as intimately associated with their microbiome, which helps improve plant nutrition, tolerance to pests, and adverse climate conditions. However, the genetic repertoire needed for efficient association with plants by the microbial symbionts is still poorly understood. The rhizobia are an exemplary model of facultative plant symbiotic microbes. Here, we evaluated whether genotype-by-genotype interactions could be identified in the initial transcriptional response of rhizobium perception of a host plant. We performed an RNA sequencing study to analyze the transcriptomes of different rhizobial strains elicited by root exudates of three alfalfa varieties as a proxy of an early step of the symbiotic interaction. The results indicated strain- and plant variety-dependent variability in the observed transcriptional changes, providing fundamentally novel insights into the genetic basis of rhizobium-plant interactions. Our results provide genetic insights and perspective to aid in the exploitation of natural rhizobium variation for improvement of legume growth in agricultural ecosystems.
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Affiliation(s)
- Camilla Fagorzi
- Department of Biology, University of Florence, Florence, Italy
| | - Giovanni Bacci
- Department of Biology, University of Florence, Florence, Italy
| | - Rui Huang
- Department of Biology, Queen's University, Kingston, Ontario, Canada
| | - Lisa Cangioli
- Department of Biology, University of Florence, Florence, Italy
| | - Alice Checcucci
- Department of Biology, University of Florence, Florence, Italy
| | - Margherita Fini
- Department of Biology, University of Florence, Florence, Italy
| | - Elena Perrin
- Department of Biology, University of Florence, Florence, Italy
| | - Chiara Natali
- Department of Biology, University of Florence, Florence, Italy
| | | | - Alessio Mengoni
- Department of Biology, University of Florence, Florence, Italy
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8
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Nonadditive Transcriptomic Signatures of Genotype-by-Genotype Interactions during the Initiation of Plant-Rhizobium Symbiosis. mSystems 2021; 6:6/1/e00974-20. [PMID: 33436514 PMCID: PMC7901481 DOI: 10.1128/msystems.00974-20] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Rhizobia are ecologically important, facultative plant-symbiotic microbes. In nature, there is a large variability in the association of rhizobial strains and host plants of the same species. Here, we evaluated whether plant and rhizobial genotypes influence the initial transcriptional response of rhizobium following perception of a host plant. RNA sequencing of the model rhizobium Sinorhizobium meliloti exposed to root exudates or luteolin (an inducer of nod genes, involved in the early steps of symbiotic interaction) was performed on a combination of three S. meliloti strains and three alfalfa varieties as host plants. The response to root exudates involved hundreds of changes in the rhizobium transcriptome. Of the differentially expressed genes, 35% were influenced by the strain genotype, 16% were influenced by the plant genotype, and 29% were influenced by strain-by-host plant genotype interactions. We also examined the response of a hybrid S. meliloti strain in which the symbiotic megaplasmid (∼20% of the genome) was mobilized between two of the above-mentioned strains. Dozens of genes were upregulated in the hybrid strain, indicative of nonadditive variation in the transcriptome. In conclusion, this study demonstrated that transcriptional responses of rhizobia upon perception of legumes are influenced by the genotypes of both symbiotic partners and their interaction, suggesting a wide spectrum of genetic determinants involved in the phenotypic variation of plant-rhizobium symbiosis.IMPORTANCE A sustainable way for meeting the need of an increased global food demand should be based on a holobiont perspective, viewing crop plants as intimately associated with their microbiome, which helps improve plant nutrition, tolerance to pests, and adverse climate conditions. However, the genetic repertoire needed for efficient association with plants by the microbial symbionts is still poorly understood. The rhizobia are an exemplary model of facultative plant symbiotic microbes. Here, we evaluated whether genotype-by-genotype interactions could be identified in the initial transcriptional response of rhizobium perception of a host plant. We performed an RNA sequencing study to analyze the transcriptomes of different rhizobial strains elicited by root exudates of three alfalfa varieties as a proxy of an early step of the symbiotic interaction. The results indicated strain- and plant variety-dependent variability in the observed transcriptional changes, providing fundamentally novel insights into the genetic basis of rhizobium-plant interactions. Our results provide genetic insights and perspective to aid in the exploitation of natural rhizobium variation for improvement of legume growth in agricultural ecosystems.
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Fu W, Pan Y, Shi Y, Chen J, Gong D, Li Y, Hao G, Han D. Root Morphogenesis of Arabidopsis thaliana Tuned by Plant Growth-Promoting Streptomyces Isolated From Root-Associated Soil of Artemisia annua. FRONTIERS IN PLANT SCIENCE 2021; 12:802737. [PMID: 35082816 PMCID: PMC8786036 DOI: 10.3389/fpls.2021.802737] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 11/25/2021] [Indexed: 05/15/2023]
Abstract
In this study, the capacity to tune root morphogenesis by a plant growth-promoting rhizobacterium, Streptomyces lincolnensis L4, was investigated from various aspects including microbial physiology, root development, and root endophytic microbial community. Strain L4 was isolated from the root-associated soil of 7-year plantation of Artemisia annua. Aiming at revealing the promotion mechanism of Streptomyces on root growth and development, this study first evaluated the growth promotion characters of S. lincolnensis L4, followed by investigation in the effect of L4 inoculation on root morphology, endophytic microbiota of root system, and expression of genes involved in root development in Arabidopsis thaliana. Streptomyces lincolnensis L4 is able to hydrolyze organic and inorganic phosphorus, fix nitrogen, and produce IAA, ACC deaminase, and siderophore, which shaped specific structure of endophytic bacterial community with dominant Streptomyces in roots and promoted the development of roots. From the observation of root development characteristics, root length, root diameter, and the number of root hairs were increased by inoculation of strain L4, which were verified by the differential expression of root development-related genes in A. thaliana. Genomic traits of S. lincolnensis L4 which further revealed its capacity for plant growth promotion in which genes involved in phosphorus solubilization, ACC deamination, iron transportation, and IAA production were identified. This root growth-promoting strain has the potential to develop green method for regulating plant development. These findings provide us ecological knowledge of microenvironment around root system and a new approach for regulating root development.
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Affiliation(s)
- Wenbo Fu
- School of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yanshuo Pan
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
- College of Natural Resources and Environment, Northwest Agriculture and Forestry University, Yangling, China
| | - Yuhua Shi
- Key Laboratory of Beijing for Identification and Safety Evaluation of Chinese Medicine, Institute of Chinese Material Medica, China Academy of Chinese Medical Sciences, Beijing, China
| | - Jieyin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Daozhi Gong
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Yuzhong Li
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Guangfei Hao
- School of Life Sciences and Food Engineering, Hebei University of Engineering, Handan, China
- *Correspondence: Guangfei Hao,
| | - Dongfei Han
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
- Dongfei Han,
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Wilhelm RC, Cyle KT, Martinez CE, Karasz DC, Newman JD, Buckley DH. Paraburkholderia solitsugae sp. nov. and Paraburkholderia elongata sp. nov., phenolic acid-degrading bacteria isolated from forest soil and emended description of Paraburkholderia madseniana. Int J Syst Evol Microbiol 2020; 70:5093-5105. [PMID: 32809929 DOI: 10.1099/ijsem.0.004387] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Two bacterial strains, 1NT and 5NT, were isolated from hemlock forest soil using a soluble organic matter enrichment. Cells of 1NT (0.65×1.85 µm) and 5NT (0.6×1.85 µm) are Gram-stain-negative, aerobic, motile, non-sporulating and exist as single rods, diplobacilli or in chains of varying length. During growth in dilute media (≤0.1× tryptic soy broth; TSB), cells are primarily motile with flagella. At higher concentrations (≥0.3× TSB), cells of both strains increasingly form non-motile chains, and cells of 5NT elongate (0.57×~7 µm) and form especially long filaments. Optimum growth of 1NT and 5NT occurred at 25-30 °C, pH 6.5-7.0 and <0.5% salinity. Results of comparative chemotaxonomic, genomic and phylogenetic analyses revealed that 1NT and 5NT were distinct from one another and their closest related type strains: Paraburkholderia madseniana RP11T, Paraburkholderia aspalathi LMG 27731T and Paraburkholderia caffeinilytica CF1T. The genomes of 1NT and 5NT had an average nucleotide identity (91.6 and 91.3%) and in silico DNA-DNA hybridization values (45.8%±2.6 and 45.5%±2.5) and differed in functional gene content from their closest related type strains. The composition of fatty acids and patterns of substrate use, including the catabolism of phenolic acids, also differentiated strains 1NT and 5NT from each other and their closest relatives. The only ubiquinone present in strains 1NT and 5NT was Q-8. The major cellular fatty acids were C16 : 0, 3OH-C16 : 0, C17 : 0 cyclo, C19 : 0 cyclo ω8c and summed features 2 (3OH-C14 : 0 / C16 : 1 iso I), 3 (C16 : 1 ω6c/ω7c) and 8 (C18 : 1 ω7c/ω6c). A third bacterium, strain RL16-012-BIC-B, was isolated from soil associated with shallow roots and was determined to be a strain of P. madseniana (ANI, 98.8%; 16S rRNA gene similarity, 100%). Characterizations of strain RL16-012-BIC-B (DSM 110723=LMG 31706) led to proposed emendments to the species description of P. madseniana. Our polyphasic approach demonstrated that strains 1NT and 5NT represent novel species from the genus Paraburkholderia for which the names Paraburkholderia solitsugae sp. nov. (type strain 1NT=DSM 110721T=LMG 31704T) and Paraburkholderia elongata sp. nov. (type strain 5NT=DSM 110722T=LMG 31705T) are proposed.
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Affiliation(s)
- Roland C Wilhelm
- School of Integrative Plant Sciences, Bradfield Hall, Cornell University, Ithaca, NY, 14853, USA
| | - K Taylor Cyle
- School of Integrative Plant Sciences, Bradfield Hall, Cornell University, Ithaca, NY, 14853, USA
| | - Carmen Enid Martinez
- School of Integrative Plant Sciences, Bradfield Hall, Cornell University, Ithaca, NY, 14853, USA
| | - David C Karasz
- School of Integrative Plant Sciences, Bradfield Hall, Cornell University, Ithaca, NY, 14853, USA
| | | | - Daniel H Buckley
- School of Integrative Plant Sciences, Bradfield Hall, Cornell University, Ithaca, NY, 14853, USA
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Fagorzi C, Ilie A, Decorosi F, Cangioli L, Viti C, Mengoni A, diCenzo GC. Symbiotic and Nonsymbiotic Members of the Genus Ensifer (syn. Sinorhizobium) Are Separated into Two Clades Based on Comparative Genomics and High-Throughput Phenotyping. Genome Biol Evol 2020; 12:2521-2534. [PMID: 33283865 PMCID: PMC7719227 DOI: 10.1093/gbe/evaa221] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2020] [Indexed: 01/03/2023] Open
Abstract
Rhizobium–legume symbioses serve as paradigmatic examples for the study of mutualism evolution. The genus Ensifer (syn. Sinorhizobium) contains diverse plant-associated bacteria, a subset of which can fix nitrogen in symbiosis with legumes. To gain insights into the evolution of symbiotic nitrogen fixation (SNF), and interkingdom mutualisms more generally, we performed extensive phenotypic, genomic, and phylogenetic analyses of the genus Ensifer. The data suggest that SNF likely emerged several times within the genus Ensifer through independent horizontal gene transfer events. Yet, the majority (105 of 106) of the Ensifer strains with the nodABC and nifHDK nodulation and nitrogen fixation genes were found within a single, monophyletic clade. Comparative genomics highlighted several differences between the “symbiotic” and “nonsymbiotic” clades, including divergences in their pangenome content. Additionally, strains of the symbiotic clade carried 325 fewer genes, on average, and appeared to have fewer rRNA operons than strains of the nonsymbiotic clade. Initial characterization of a subset of ten Ensifer strains identified several putative phenotypic differences between the clades. Tested strains of the nonsymbiotic clade could catabolize 25% more carbon sources, on average, than strains of the symbiotic clade, and they were better able to grow in LB medium and tolerate alkaline conditions. On the other hand, the tested strains of the symbiotic clade were better able to tolerate heat stress and acidic conditions. We suggest that these data support the division of the genus Ensifer into two main subgroups, as well as the hypothesis that pre-existing genetic features are required to facilitate the evolution of SNF in bacteria.
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Affiliation(s)
- Camilla Fagorzi
- Department of Biology, University of Florence, Sesto Fiorentino, Italy
| | - Alexandru Ilie
- Department of Biology, University of Florence, Sesto Fiorentino, Italy
| | - Francesca Decorosi
- Genexpress Laboratory, Department of Agriculture, Food, Environment and Forestry, University of Florence, Sesto Fiorentino, Italy
| | - Lisa Cangioli
- Department of Biology, University of Florence, Sesto Fiorentino, Italy
| | - Carlo Viti
- Genexpress Laboratory, Department of Agriculture, Food, Environment and Forestry, University of Florence, Sesto Fiorentino, Italy
| | - Alessio Mengoni
- Department of Biology, University of Florence, Sesto Fiorentino, Italy
| | - George C diCenzo
- Department of Biology, University of Florence, Sesto Fiorentino, Italy.,Department of Biology, Queen's University, Kingston, Ontario, Canada
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Leontidou K, Genitsaris S, Papadopoulou A, Kamou N, Bosmali I, Matsi T, Madesis P, Vokou D, Karamanoli K, Mellidou I. Plant growth promoting rhizobacteria isolated from halophytes and drought-tolerant plants: genomic characterisation and exploration of phyto-beneficial traits. Sci Rep 2020; 10:14857. [PMID: 32908201 PMCID: PMC7481233 DOI: 10.1038/s41598-020-71652-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 08/17/2020] [Indexed: 01/25/2023] Open
Abstract
Plant growth promoting rhizobacteria (PGPR) are able to provide cross-protection against multiple stress factors and facilitate growth of their plant symbionts in many ways. The aim of this study was to isolate and characterize rhizobacterial strains under natural conditions, associated with naturally occurring representatives of wild plant species and a local tomato cultivar, growing in differently stressed Mediterranean ecosystems. A total of 85 morphologically different rhizospheric strains were isolated; twenty-five exhibited multiple in vitro PGP-associated traits, including phosphate solubilization, indole-3-acetic acid production, and 1-aminocyclopropane-1-carboxylate deaminase activity. Whole genome analysis was applied to eight selected strains for their PGP potential and assigned seven strains to Gammaproteobacteria, and one to Bacteroidetes. The genomes harboured numerous genes involved in plant growth promotion and stress regulation. They also support the notion that the presence of gene clusters with potential PGP functions is affirmative but not necessary for a strain to promote plant growth under abiotic stress conditions. The selected strains were further tested for their ability to stimulate growth under stress. This initial screening led to the identification of some strains as potential PGPR for increasing crop production in a sustainable manner.
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Affiliation(s)
- Kleopatra Leontidou
- Laboratory of Agricultural Chemistry, School of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Savvas Genitsaris
- International Hellenic University, 57001, Thermi, Greece.,Department of Ecology, School of Biology, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Anastasia Papadopoulou
- Laboratory of Agricultural Chemistry, School of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Nathalie Kamou
- Laboratory of Agricultural Chemistry, School of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Irene Bosmali
- Institute of Applied Biosciences, CERTH, 57001, Thessaloniki, Greece
| | - Theodora Matsi
- Soil Science Laboratory, School of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | | | - Despoina Vokou
- Department of Ecology, School of Biology, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece
| | - Katerina Karamanoli
- Laboratory of Agricultural Chemistry, School of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece.
| | - Ifigeneia Mellidou
- Laboratory of Agricultural Chemistry, School of Agriculture, Aristotle University of Thessaloniki, 54124, Thessaloniki, Greece. .,Institute of Plant Breeding and Genetic Resources, HAO, 57001, Thermi, Thessaloniki, Greece.
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13
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Potrykus M, Decorosi F, Perkowska I, Viti C, Mengoni A, Hugouvieux-Cotte-Pattat N, Lojkowska E. The metabolic shift in highly and weakly virulent Dickeya solani strains is more affected by temperature than by mutations in genes encoding global virulence regulators. FEMS Microbiol Ecol 2020; 96:5739916. [PMID: 32068796 DOI: 10.1093/femsec/fiaa023] [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] [Received: 12/01/2019] [Accepted: 02/17/2020] [Indexed: 11/13/2022] Open
Abstract
Global warming may shortly increase the risk of disease development on plants. Significant differences in the metabolic activity screened with Phenotype Microarray at 22°C and 28°C were observed between D. solani strains with high and low virulence level. Highly virulent D. solani was characterized by a higher number of metabolized compounds and a faster metabolism and was more tolerant to non-favorable pH and osmolarity. Metabolic phenotyping showed for the first time that the mutation in pecT gene, which encodes a global repressor of virulence, affects several pathways of the basic cell metabolism. PecT mutants had a higher maceration capacity of potato tissue and showed a higher pectinolytic activity than the wild-type strains. On the contrary, mutation in expI gene, which encoded the signaling molecules synthase crucial for quorum sensing, had an insignificant effect on the cell metabolism, although it slightly reduced the potato tissue maceration. The ability to utilize most of the tested compounds was higher at 28°C, while the survival at non-favorable pH and osmolarity was higher at 22°C. These results proved that the temperature of incubation had the most significant impact on the D. solani metabolic profiles.
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Affiliation(s)
- Marta Potrykus
- Department of Plant Protection and Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland.,Department of Environmental Toxicology, Faculty of Health Sciences with Institute of Maritime and Tropical Medicine, Medical University of Gdansk, Debowa 23A, 80-204 Gdansk, Poland
| | - Francesca Decorosi
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Via della Lastruccia, 10 - 50019 Sesto Fiorentino, Italy
| | - Izabela Perkowska
- Department of Plant Protection and Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
| | - Carlo Viti
- Department of Agriculture, Food, Environment and Forestry (DAGRI), University of Florence, Via della Lastruccia, 10 - 50019 Sesto Fiorentino, Italy
| | - Alessio Mengoni
- Department of Biology, University of Florence, Via Madonna del Piano, 6 50019 Sesto Fiorentino, Italy
| | - Nicole Hugouvieux-Cotte-Pattat
- Microbiologie Adaptation et Pathogénie, Univ Lyon, CNRS UMR5240, Univ Claude Bernard Lyon 1, INSA de Lyon, F-69622 Villeurbanne, France
| | - Ewa Lojkowska
- Department of Plant Protection and Biotechnology, Intercollegiate Faculty of Biotechnology, University of Gdansk and Medical University of Gdansk, Abrahama 58, 80-307 Gdansk, Poland
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14
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Deciphering the Symbiotic Plant Microbiome: Translating the Most Recent Discoveries on Rhizobia for the Improvement of Agricultural Practices in Metal-Contaminated and High Saline Lands. AGRONOMY-BASEL 2019. [DOI: 10.3390/agronomy9090529] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Rhizosphere and plant-associated microorganisms have been intensely studied for their beneficial effects on plant growth and health. These mainly include nitrogen-fixing bacteria (NFB) and plant-growth promoting rhizobacteria (PGPR). This beneficial fraction is involved in major functions such as plant nutrition and plant resistance to biotic and abiotic stresses, which include water deficiency and heavy-metal contamination. Consequently, crop yield emerges as the net result of the interactions between the plant genome and its associated microbiome. Here, we provide a review covering recent studies on PGP rhizobia as effective inoculants for agricultural practices in harsh soil, and we propose models for inoculant combinations and genomic manipulation strategies to improve crop yield.
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15
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Revealing the roles of y4wF and tidC genes in Rhizobium tropici CIAT 899: biosynthesis of indolic compounds and impact on symbiotic properties. Arch Microbiol 2018; 201:171-183. [PMID: 30535938 DOI: 10.1007/s00203-018-1607-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2018] [Revised: 11/26/2018] [Accepted: 12/03/2018] [Indexed: 01/06/2023]
Abstract
Rhizobium tropici CIAT 899 is a strain known by its ability to nodulate a broad range of legume species, to synthesize a variety of Nod factors, its tolerance of abiotic stresses, and its high capacity to fix atmospheric N2, especially in symbiosis with common bean (Phaseolus vulgaris L.). Genes putatively related to the synthesis of indole acetic acid (IAA) have been found in the symbiotic plasmid of CIAT 899, in the vicinity of the regulatory nodulation gene nodD5, and, in this study, we obtained mutants for two of these genes, y4wF and tidC (R. tropiciindole-3-pyruvic acid decarboxylase), and investigated their expression in the absence and presence of tryptophan (TRP) and apigenin (API). In general, mutations of both genes increased exopolysaccharide (EPS) synthesis and did not affect swimming or surface motility; mutations also delayed nodule formation, but increased competitiveness. We found that the indole-3-acetamide (IAM) pathway was active in CIAT 899 and not affected by the mutations, and-noteworthy-that API was required to activate the tryptamine (TAM) and the indol-3-pyruvic acid (IPyA) pathways in all strains, particularly in the mutants. High up-regulation of y4wF and tidC genes was observed in both the wild-type and the mutant strains in the presence of API. The results obtained revealed an intriguing relationship between IAA metabolism and nod-gene-inducing activity in R. tropici CIAT 899. We discuss the IAA pathways, and, based on our results, we attribute functions to the y4wF and tidC genes of R. tropici.
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Checcucci A, diCenzo GC, Ghini V, Bazzicalupo M, Becker A, Decorosi F, Döhlemann J, Fagorzi C, Finan TM, Fondi M, Luchinat C, Turano P, Vignolini T, Viti C, Mengoni A. Creation and Characterization of a Genomically Hybrid Strain in the Nitrogen-Fixing Symbiotic Bacterium Sinorhizobium meliloti. ACS Synth Biol 2018; 7:2365-2378. [PMID: 30223644 DOI: 10.1021/acssynbio.8b00158] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Many bacteria, often associated with eukaryotic hosts and of relevance for biotechnological applications, harbor a multipartite genome composed of more than one replicon. Biotechnologically relevant phenotypes are often encoded by genes residing on the secondary replicons. A synthetic biology approach to developing enhanced strains for biotechnological purposes could therefore involve merging pieces or entire replicons from multiple strains into a single genome. Here we report the creation of a genomic hybrid strain in a model multipartite genome species, the plant-symbiotic bacterium Sinorhizobium meliloti. We term this strain as cis-hybrid, since it is produced by genomic material coming from the same species' pangenome. In particular, we moved the secondary replicon pSymA (accounting for nearly 20% of total genome content) from a donor S. meliloti strain to an acceptor strain. The cis-hybrid strain was screened for a panel of complex phenotypes (carbon/nitrogen utilization phenotypes, intra- and extracellular metabolomes, symbiosis, and various microbiological tests). Additionally, metabolic network reconstruction and constraint-based modeling were employed for in silico prediction of metabolic flux reorganization. Phenotypes of the cis-hybrid strain were in good agreement with those of both parental strains. Interestingly, the symbiotic phenotype showed a marked cultivar-specific improvement with the cis-hybrid strains compared to both parental strains. These results provide a proof-of-principle for the feasibility of genome-wide replicon-based remodelling of bacterial strains for improved biotechnological applications in precision agriculture.
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Affiliation(s)
- Alice Checcucci
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - George C. diCenzo
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Veronica Ghini
- CERM & CIRMMP, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Marco Bazzicalupo
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Anke Becker
- LOEWE − Center for Synthetic Microbiology, 35043 Marburg, Germany
| | - Francesca Decorosi
- Department of Agri-food Production and Environmental Science, University of Florence, 50019 Florence, Italy
| | | | - Camilla Fagorzi
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Turlough M. Finan
- Department of Biology, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Marco Fondi
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Claudio Luchinat
- CERM & CIRMMP, University of Florence, 50019 Sesto Fiorentino, Italy
- CERM and Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Paola Turano
- CERM & CIRMMP, University of Florence, 50019 Sesto Fiorentino, Italy
- CERM and Department of Chemistry, University of Florence, 50019 Sesto Fiorentino, Italy
| | - Tiziano Vignolini
- European Laboratory for Non-Linear Spectroscopy, LENS, 50019 Sesto Fiorentino, Italy
| | - Carlo Viti
- Department of Agri-food Production and Environmental Science, University of Florence, 50019 Florence, Italy
| | - Alessio Mengoni
- Department of Biology, University of Florence, 50019 Sesto Fiorentino, Italy
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17
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Checcucci A, DiCenzo GC, Bazzicalupo M, Mengoni A. Trade, Diplomacy, and Warfare: The Quest for Elite Rhizobia Inoculant Strains. Front Microbiol 2017; 8:2207. [PMID: 29170661 PMCID: PMC5684177 DOI: 10.3389/fmicb.2017.02207] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 10/26/2017] [Indexed: 01/12/2023] Open
Abstract
Rhizobia form symbiotic nitrogen-fixing nodules on leguminous plants, which provides an important source of fixed nitrogen input into the soil ecosystem. The improvement of symbiotic nitrogen fixation is one of the main challenges facing agriculture research. Doing so will reduce the usage of chemical nitrogen fertilizer, contributing to the development of sustainable agriculture practices to deal with the increasing global human population. Sociomicrobiological studies of rhizobia have become a model for the study of the evolution of mutualistic interactions. The exploitation of the wide range of social interactions rhizobia establish among themselves, with the soil and root microbiota, and with the host plant, could constitute a great advantage in the development of a new generation of highly effective rhizobia inoculants. Here, we provide a brief overview of the current knowledge on three main aspects of rhizobia interaction: trade of fixed nitrogen with the plant; diplomacy in terms of communication and possible synergistic effects; and warfare, as antagonism and plant control over symbiosis. Then, we propose new areas of investigation and the selection of strains based on the combination of the genetic determinants for the relevant rhizobia symbiotic behavioral phenotypes.
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Affiliation(s)
- Alice Checcucci
- Department of Biology, University of Florence, Florence, Italy
| | | | | | - Alessio Mengoni
- Department of Biology, University of Florence, Florence, Italy
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18
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Rivilla R, Martín M, Lloret J. What makes rhizobia rhizosphere colonizers? Environ Microbiol 2017; 19:4379-4381. [PMID: 28892276 DOI: 10.1111/1462-2920.13917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 08/26/2017] [Indexed: 11/28/2022]
Affiliation(s)
- Rafael Rivilla
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Darwin 2. 28049, Spain
| | - Marta Martín
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Darwin 2. 28049, Spain
| | - Javier Lloret
- Departamento de Biología, Universidad Autónoma de Madrid, Madrid, Darwin 2. 28049, Spain
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