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Han F, Li H, Lyu E, Zhang Q, Gai H, Xu Y, Bai X, He X, Khan AQ, Li X, Xie F, Li F, Fang X, Wei M. Soybean-mediated suppression of BjaI/BjaR 1 quorum sensing in Bradyrhizobium diazoefficiens impacts symbiotic nitrogen fixation. Appl Environ Microbiol 2024; 90:e0137423. [PMID: 38251894 PMCID: PMC10880635 DOI: 10.1128/aem.01374-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/23/2023] [Indexed: 01/23/2024] Open
Abstract
The acyl-homoserine lactones (AHLs)-mediated LuxI/LuxR quorum sensing (QS) system orchestrates diverse bacterial behaviors in response to changes in population density. The role of the BjaI/BjaR1 QS system in Bradyrhizobium diazoefficiens USDA 110, which shares homology with LuxI/LuxR, remains elusive during symbiotic interaction with soybean. Here this genetic system in wild-type (WT) bacteria residing inside nodules exhibited significantly reduced activity compared to free-living cells, potentially attributed to soybean-mediated suppression. The deletion mutant strain ΔbjaR1 showed significantly enhanced nodulation induction and nitrogen fixation ability. Nevertheless, its ultimate symbiotic outcome (plant dry weight) in soybeans was compromised. Furthermore, comparative analysis of the transcriptome, proteome, and promoter activity revealed that the inactivation of BjaR1 systematically activated and inhibited genomic modules associated with nodulation and nitrogen metabolism. The former appeared to be linked to a significant decrease in the expression of NodD2, a key cell-density-dependent repressor of nodulation genes, while the latter conferred bacterial growth and nitrogen fixation insensitivity to environmental nitrogen. In addition, BjaR1 exerted a positive influence on the transcription of multiple genes involved in a so-called central intermediate metabolism within the nodule. In conclusion, our findings highlight the crucial role of the BjaI/BjaR1 QS circuit in positively regulating bacterial nitrogen metabolism and emphasize the significance of the soybean-mediated suppression of this genetic system for promoting efficient symbiotic nitrogen fixation by B. diazoefficiens.IMPORTANCEThe present study demonstrates, for the first time, that the BjaI/BjaR1 QS system of Bradyrhizobium diazoefficiens has a significant impact on its nodulation and nitrogen fixation capability in soybean by positively regulating NodD2 expression and bacterial nitrogen metabolism. Moreover, it provides novel insights into the importance of suppressing the activity of this QS circuit by the soybean host plant in establishing an efficient mutual relationship between the two symbiotic partners. This research expands our understanding of legumes' role in modulating symbiotic nitrogen fixation through rhizobial QS-mediated metabolic functioning, thereby deepening our comprehension of symbiotic coevolution theory. In addition, these findings may hold great promise for developing quorum quenching technology in agriculture.
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Affiliation(s)
- Fang Han
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Huiquan Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Ermeng Lyu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Qianqian Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Haoyu Gai
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Yunfang Xu
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Xuemei Bai
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Xueqian He
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Abdul Qadir Khan
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Xiaolin Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Fang Xie
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai, China
| | - Fengmin Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Xiangwen Fang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
| | - Min Wei
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou, China
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Yajima A, Katsuta R, Shimura M, Yoshihara A, Saito T, Ishigami K, Kai K. Disproof of the Proposed Structures of Bradyoxetin, a Putative Bradyrhizobium japonicum Signaling Molecule, and HMCP, a Putative Ralstonia solanacearum Quorum-Sensing Molecule. JOURNAL OF NATURAL PRODUCTS 2021; 84:495-502. [PMID: 33513023 DOI: 10.1021/acs.jnatprod.0c01369] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
First, we revisited the reported NMR data of bradyoxetin, a putative cell density factor of Bradyrhizobium japonicum, and found some inconsistencies in the proposed structure. To elucidate the correct structure, we synthesized model oxetane compounds and confirmed that the NMR data of the synthetic compounds did not match those of the reported bradyoxetin. After reinterpreting the reported NMR data, we concluded that bradyoxetin must be chloramphenicol. Next, some derivatives of 2-hydroxy-4-((methylamino)(phenyl)methyl)cyclopentanone (HMCP), which is a putative quorum-sensing molecule of Ralstonia solanacearum, were synthesized. The NMR spectra of the synthesized compounds were completely different from those of the reported natural products. Based on theoretical studies, including the estimation of 1H and 13C NMR chemical shifts using density functional theory calculations, we confirmed the correctness of the structure of the synthesized compound. These results strongly suggest that the proposed structure of HMCP could be incorrect.
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Affiliation(s)
- Arata Yajima
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences, Tokyo University of Agriculture, Setagaya-ku, Sakuragaoka 1-1-1, Tokyo 156-8502, Japan
| | - Ryo Katsuta
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences, Tokyo University of Agriculture, Setagaya-ku, Sakuragaoka 1-1-1, Tokyo 156-8502, Japan
| | - Mikaho Shimura
- Graduate School of Agriculture, Tokyo University of Agriculture, Setagaya-ku, Sakuragaoka 1-1-1, Tokyo 156-8502, Japan
| | - Ayaka Yoshihara
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka 599-8531, Japan
| | - Tatsuo Saito
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences, Tokyo University of Agriculture, Setagaya-ku, Sakuragaoka 1-1-1, Tokyo 156-8502, Japan
| | - Ken Ishigami
- Department of Chemistry for Life Sciences and Agriculture, Faculty of Life Sciences, Tokyo University of Agriculture, Setagaya-ku, Sakuragaoka 1-1-1, Tokyo 156-8502, Japan
| | - Kenji Kai
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Gakuen-cho 1-1, Naka-ku, Sakai, Osaka 599-8531, Japan
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Communication within East Antarctic Soil Bacteria. Appl Environ Microbiol 2019; 86:AEM.01968-19. [PMID: 31628145 DOI: 10.1128/aem.01968-19] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Accepted: 10/09/2019] [Indexed: 01/01/2023] Open
Abstract
Antarctica, being the coldest, driest, and windiest continent on Earth, represents the most extreme environment in which a living organism can survive. Under constant exposure to harsh environmental threats, terrestrial Antarctica remains home to a great diversity of microorganisms, indicating that the soil bacteria must have adapted a range of survival strategies that require cell-to-cell communication. Survival strategies include secondary metabolite production, biofilm formation, bioluminescence, symbiosis, conjugation, sporulation, and motility, all of which are often regulated by quorum sensing (QS), a type of bacterial communication. Until now, such mechanisms have not been explored in terrestrial Antarctica. In this study, LuxI/LuxR-based quorum sensing (QS) activity was delineated in soil bacterial isolates recovered from Adams Flat, in the Vestfold Hills region of East Antarctica. Interestingly, we identified the production of potential homoserine lactones (HSLs) with chain lengths ranging from medium to long in 19 bacterial species using three biosensors, namely, Agrobacterium tumefaciens NTL4, Chromobacterium violaceum CV026, and Escherichia coli MT102, in conjunction with thin-layer chromatography (TLC). The majority of detectable HSLs were from Gram-positive species not previously known to produce HSLs. This discovery further expands our understanding of the microbial community capable of this type of communication, as well as provides insights into physiological adaptations of microorganisms that allow them to survive in the harsh Antarctic environment.IMPORTANCE Quorum sensing, a type of bacterial communication, is widely known to regulate many processes, including those that confer a survival advantage. However, little is known about communication by bacteria residing within Antarctic soils. Employing a combination of bacterial biosensors, analytical techniques, and genome mining, we found a variety of Antarctic soil bacteria speaking a common language, via LuxI/LuxR-based quorum sensing, thus potentially supporting survival in a mixed microbial community. This study reports potential quorum sensing activity in Antarctic soils and has provided a platform for studying physiological adaptations of microorganisms that allow them to survive in the harsh Antarctic environment.
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Dos Santos Lima Fagotti D, Abrantes JLF, Cerezini P, Fukami J, Nogueira MA, Del Cerro P, Valderrama-Fernández R, Ollero FJ, Megías M, Hungria M. Quorum sensing communication: Bradyrhizobium-Azospirillum interaction via N-acyl-homoserine lactones in the promotion of soybean symbiosis. J Basic Microbiol 2019; 59:38-53. [PMID: 30320901 DOI: 10.1002/jobm.201800324] [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: 06/28/2018] [Revised: 09/06/2018] [Accepted: 09/22/2018] [Indexed: 11/11/2022]
Abstract
Quorum-sensing (QS) mechanisms are important in intra- and inter-specific communication among bacteria. We investigated QS mechanisms in Bradyrhizobium japonicum strain CPAC 15 and Azospirillum brasilense strains Ab-V5 and Ab-V6, used in commercial co-inoculants for the soybean crop in Brazil. A transconjugant of CPAC 15-QS with partial inactivation of N-acyl-homoserine lactones (AHLs) was obtained and several parameters were evaluated; in vitro, CPAC 15 and the transconjugant differed in growth, but not in biofilm formation, and no differences were observed in the symbiotic performance in vivo. The genome of CPAC 15 carries functional luxI and luxR genes and low amounts of three AHL molecules were detected: 3-OH-C12-AHL, 3-OH-C14-AHL, and 3-oxo-C14-AHL. Multiple copies of luxR-like genes, but not of luxI are present in the genomes of Ab-V5 and Ab-V6, and differences in gene expression were observed when the strains were co-cultured with B. japonicum; we may infer that the luxR-genes of A. brasilense may perceive the AHL molecules of B. japonicum. Soybean symbiotic performance was improved especially by co-inoculation with Ab-V6, which, contrarily to Ab-V5, did not respond to the AHLs of CPAC 15. We concluded that A. brasilense Ab-V5, but not Ab-V6, responded to the QS signals of CPAC 15, and that the synergistic interaction may be credited, at least partially, to the QS interaction. In addition, we confirmed inter- and intra-species QS communication between B. japonicum and A. brasilense and, for Azospirillum, at the strain level, impacting several steps of the symbiosis, from cell growth to plant nodulation and growth.
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Affiliation(s)
- Dáfila Dos Santos Lima Fagotti
- Embrapa Soja, Londrina, Paraná, Brazil
- Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brasília, Distrito Federal, Brazil
| | - Julia Laura Fernandes Abrantes
- Embrapa Soja, Londrina, Paraná, Brazil
- Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brasília, Distrito Federal, Brazil
| | - Paula Cerezini
- Embrapa Soja, Londrina, Paraná, Brazil
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, SBN, Brasília, Distrito Federal, Brazil
| | - Josiane Fukami
- Embrapa Soja, Londrina, Paraná, Brazil
- Coordenação de Aperfeiçoamento de Pessoal de Nível Superior, SBN, Brasília, Distrito Federal, Brazil
| | - Marco A Nogueira
- Embrapa Soja, Londrina, Paraná, Brazil
- Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brasília, Distrito Federal, Brazil
| | - Pablo Del Cerro
- Facultad de Biología, Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain
| | | | - Francisco J Ollero
- Facultad de Biología, Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain
| | - Manuel Megías
- Facultad de Biología, Departamento de Microbiología, Universidad de Sevilla, Sevilla, Spain
| | - Mariangela Hungria
- Embrapa Soja, Londrina, Paraná, Brazil
- Conselho Nacional de Desenvolvimento Científico e Tecnológico, Brasília, Distrito Federal, Brazil
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Sun Y, Guan Y, Wang D, Liang K, Wu G. Potential roles of acyl homoserine lactone based quorum sensing in sequencing batch nitrifying biofilm reactors with or without the addition of organic carbon. BIORESOURCE TECHNOLOGY 2018; 259:136-145. [PMID: 29549833 DOI: 10.1016/j.biortech.2018.03.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 03/04/2018] [Accepted: 03/05/2018] [Indexed: 05/03/2023]
Abstract
Two lab-scale nitrifying sequencing batch biofilm reactors, with (SBBR_CN) or without the addition of organics (SBBR_N), were operated to investigate potential roles of acyl homoserine lactone (AHL) based quorum sensing. AHLs of N-[(RS)-3-Hydroxybutyryl]-L-homoserine lactone, N-hexanoyl-L-homoserine lactone (C6-HSL) and N-octanoyl-L-homoserine lactone (C8-HSL) were detected in both reactors. C6-HSL and C8-HSL were also detected in batch experiments, especially with stimulated nitrite oxidizing bacteria activities. Quorum sensing affected biofilm formation mainly through the regulation of extracellular protein production. By the metagenomics analysis, many identified genera and species could participate in quorum sensing, quorum quenching and extracellular polymeric substances (EPS) production. A high quorum quenching activity was obtained in SBBR_CN, whereas a high quorum sensing activity in SBBR_N. Nitrosomonas-like ammonia oxidizing bacteria, Nitrospira-like nitrite oxidizing bacteria and Comammox harbored genes for AHL synthesis and EPS production. Possible relationships among AHLs synthesis, biofilm formation and nitrifiers activity were proposed.
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Affiliation(s)
- Yuepeng Sun
- Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Yuntao Guan
- Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Dan Wang
- Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Kai Liang
- Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China
| | - Guangxue Wu
- Guangdong Province Engineering Research Center for Urban Water Recycling and Environmental Safety, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
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Calatrava-Morales N, McIntosh M, Soto MJ. Regulation Mediated by N-Acyl Homoserine Lactone Quorum Sensing Signals in the Rhizobium-Legume Symbiosis. Genes (Basel) 2018; 9:genes9050263. [PMID: 29783703 PMCID: PMC5977203 DOI: 10.3390/genes9050263] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Revised: 05/15/2018] [Accepted: 05/15/2018] [Indexed: 02/06/2023] Open
Abstract
Soil-dwelling bacteria collectively referred to as rhizobia synthesize and perceive N-acyl-homoserine lactone (AHL) signals to regulate gene expression in a population density-dependent manner. AHL-mediated signaling in these bacteria regulates several functions which are important for the establishment of nitrogen-fixing symbiosis with legume plants. Moreover, rhizobial AHL act as interkingdom signals triggering plant responses that impact the plant-bacteria interaction. Both the regulatory mechanisms that control AHL synthesis in rhizobia and the set of bacterial genes and associated traits under quorum sensing (QS) control vary greatly among the rhizobial species. In this article, we focus on the well-known QS system of the alfalfa symbiont Sinorhizobium(Ensifer)meliloti. Bacterial genes, environmental factors and transcriptional and posttranscriptional regulatory mechanisms that control AHL production in this Rhizobium, as well as the effects of the signaling molecule on bacterial phenotypes and plant responses will be reviewed. Current knowledge of S. meliloti QS will be compared with that of other rhizobia. Finally, participation of the legume host in QS by interfering with rhizobial AHL perception through the production of molecular mimics will also be addressed.
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Affiliation(s)
- Nieves Calatrava-Morales
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC; Granada 18008, Spain.
| | - Matthew McIntosh
- Institut für Mikrobiologie und Molekularbiologie, Universität Giessen, 35392 Giessen, Germany.
| | - María J Soto
- Departamento de Microbiología del Suelo y Sistemas Simbióticos, Estación Experimental del Zaidín, CSIC; Granada 18008, Spain.
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Ali A, Ayesha, Hameed S, Imran A, Iqbal M, Iqbal J, Oresnik IJ. Functional characterization of a soybean growth stimulator Bradyrhizobium sp. strain SR-6 showing acylhomoserine lactone production. FEMS Microbiol Ecol 2016; 92:fiw115. [PMID: 27242370 DOI: 10.1093/femsec/fiw115] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/21/2016] [Indexed: 01/09/2023] Open
Abstract
A soybean nodule endophytic bacterium Bradyrhizobium sp. strain SR-6 was characterized for production of acyl homoserine lactones (AHLs) as quorum sensing molecules. Mass spectrometry analysis of AHLs revealed the presence of C6-HSL, 3OH-C6-HSL, C8-HSL, C10-HSL, 3oxoC10-HSL, 3oxo-C12-HSL and 3OH-C12-HSL which are significantly different from those reported earlier in soybean symbionts. Purified AHL extracts significantly improved wheat and soybean seedling growth and root hair development along with increased soybean nodulation under axenic conditions. A positive correlation was observed among in vivo nitrogenase and catalase enzyme activities of the strain SR-6. Transmission electron microscopic analysis showed the cytochemical localization of catalase activity within the bacteroids, specifically attached to the peribacteroidal membrane. Root and nodule colonization proved rhizosphere competence of SR-6. The inoculation of SR-6 resulted in increased shoot length (13%), plant dry matter (50%), grain weight (16%), seed yield (20%) and N-uptake (14%) as compared to non-inoculated soybean plants. The symbiotic bacterium SR-6 has potential to improve soybean growth and yield in sub-humid climate of Azad Jammu and Kashmir region of Pakistan. The production and mass spectrometric profiling of AHLs as well as in vivo cytochemical localization of catalase enzyme activity in soybean Bradyrhizobium sp. have never been reported earlier elsewhere before our these investigations.
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Affiliation(s)
- Amanat Ali
- Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road, PO Box no. 577, Faisalabad 38000, Pakistan
| | - Ayesha
- Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road, PO Box no. 577, Faisalabad 38000, Pakistan
| | - Sohail Hameed
- Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road, PO Box no. 577, Faisalabad 38000, Pakistan
| | - Asma Imran
- Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road, PO Box no. 577, Faisalabad 38000, Pakistan
| | - Mazhar Iqbal
- Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road, PO Box no. 577, Faisalabad 38000, Pakistan
| | - Javed Iqbal
- Soil and Environmental Biotechnology Division, National Institute for Biotechnology and Genetic Engineering (NIBGE), Jhang Road, PO Box no. 577, Faisalabad 38000, Pakistan
| | - Ivan J Oresnik
- Department of Microbiology, University of Manitoba, Winnipeg, Manitoba, R3T 2N2 Canada
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Siqueira AF, Ormeño-Orrillo E, Souza RC, Rodrigues EP, Almeida LGP, Barcellos FG, Batista JSS, Nakatani AS, Martínez-Romero E, Vasconcelos ATR, Hungria M. Comparative genomics of Bradyrhizobium japonicum CPAC 15 and Bradyrhizobium diazoefficiens CPAC 7: elite model strains for understanding symbiotic performance with soybean. BMC Genomics 2014; 15:420. [PMID: 24888481 PMCID: PMC4070871 DOI: 10.1186/1471-2164-15-420] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Accepted: 05/20/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The soybean-Bradyrhizobium symbiosis can be highly efficient in fixing nitrogen, but few genomic sequences of elite inoculant strains are available. Here we contribute with information on the genomes of two commercial strains that are broadly applied to soybean crops in the tropics. B. japonicum CPAC 15 (=SEMIA 5079) is outstanding in its saprophytic capacity and competitiveness, whereas B. diazoefficiens CPAC 7 (=SEMIA 5080) is known for its high efficiency in fixing nitrogen. Both are well adapted to tropical soils. The genomes of CPAC 15 and CPAC 7 were compared to each other and also to those of B. japonicum USDA 6T and B. diazoefficiens USDA 110T. RESULTS Differences in genome size were found between species, with B. japonicum having larger genomes than B. diazoefficiens. Although most of the four genomes were syntenic, genome rearrangements within and between species were observed, including events in the symbiosis island. In addition to the symbiotic region, several genomic islands were identified. Altogether, these features must confer high genomic plasticity that might explain adaptation and differences in symbiotic performance. It was not possible to attribute known functions to half of the predicted genes. About 10% of the genomes was composed of exclusive genes of each strain, but up to 98% of them were of unknown function or coded for mobile genetic elements. In CPAC 15, more genes were associated with secondary metabolites, nutrient transport, iron-acquisition and IAA metabolism, potentially correlated with higher saprophytic capacity and competitiveness than seen with CPAC 7. In CPAC 7, more genes were related to the metabolism of amino acids and hydrogen uptake, potentially correlated with higher efficiency of nitrogen fixation than seen with CPAC 15. CONCLUSIONS Several differences and similarities detected between the two elite soybean-inoculant strains and between the two species of Bradyrhizobium provide new insights into adaptation to tropical soils, efficiency of N2 fixation, nodulation and competitiveness.
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Affiliation(s)
- Arthur Fernandes Siqueira
- />Department Biochemistry and Biotechnology, Universidade Estadual de Londrina (UEL), C.P. 60001, Londrina, PR 86051-990 Brazil
- />Embrapa Soja, C.P. 231, Londrina, PR 86001-970 Brazil
| | - Ernesto Ormeño-Orrillo
- />Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos Mexico
| | - Rangel Celso Souza
- />Laboratório Nacional de Computação Científica, Rua Getúlio Vargas 333, Petrópolis, RJ 25651-071 Brazil
| | | | - Luiz Gonzaga Paula Almeida
- />Laboratório Nacional de Computação Científica, Rua Getúlio Vargas 333, Petrópolis, RJ 25651-071 Brazil
| | | | - Jesiane Stefânia Silva Batista
- />Department Structural, Molecular and Genetic Biology, Universidade Estadual de Ponta Grossa (UEPG), Av. General Carlos Cavalcanti 4748, Ponta Grossa, PR 84030-900 Brazil
| | | | | | | | - Mariangela Hungria
- />Department Biochemistry and Biotechnology, Universidade Estadual de Londrina (UEL), C.P. 60001, Londrina, PR 86051-990 Brazil
- />Embrapa Soja, C.P. 231, Londrina, PR 86001-970 Brazil
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Sugawara M, Sadowsky MJ. Enhanced nodulation and nodule development by nolR mutants of Sinorhizobium medicae on specific Medicago host genotypes. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2014; 27:328-335. [PMID: 24283939 DOI: 10.1094/mpmi-10-13-0312-r] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
The nolR gene encodes a negatively acting, transcriptional regulatory protein of core Nod-factor biosynthetic genes in the sinorhizobia. Although previous reports showed that nolR modulates Nod-factor production and enhances nodulation speed of Sinorhizobium meliloti on alfalfa, there have been no reports for the symbiotic function of this gene in the S. medicae-Medicago truncatula symbiosis. Here, we constructed an nolR mutant of S. medicae WSM419 and evaluated mutant and wild-type strains for their nodulation ability, competitiveness, host specificity, and density-dependent nodulation phenotypes. When the mutant was inoculated at low and medium population densities, it showed enhanced nodule formation during the initial stages of nodulation. Results of quantitative competitive nodulation assays indicated that an nolR mutant had 2.3-fold greater competitiveness for nodulation on M. truncatula 'A17' than did the wild-type strain. Moreover, the nodulation phenotype of the nolR mutant differed among Medicago genotypes and showed significantly enhanced nodule development on M. tricycla. Taken together, these results indicated that mutation of nolR in S. medicae positively influenced nodule initiation, competitive nodulation, and nodule development at later nodulation stages. This may allow nolR mutants of S. medicae to have a selective advantage under field conditions.
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Zhang QQ, Wang HH, Zhuang S, Xiao HM, Xu XL, Zhou GH. Application of Mathematical Model for the Quantification of Acylated Homoserine Lactones Produces by P
seudomonas aeruginosa
in Chicken Breast Meat and Broth. J Food Saf 2013. [DOI: 10.1111/jfs.12079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Qiu-Qin Zhang
- Key Laboratory of Meat Processing and Quality Control; Ministry of Education; College of Food Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Hu-Hu Wang
- Key Laboratory of Meat Processing and Quality Control; Ministry of Education; College of Food Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Su Zhuang
- College of Animal Science and Technology; Nanjing Agricultural University; Nanjing China
| | - Hong-Mei Xiao
- Key Laboratory of Meat Processing and Quality Control; Ministry of Education; College of Food Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Xing-Lian Xu
- Key Laboratory of Meat Processing and Quality Control; Ministry of Education; College of Food Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
| | - Guang-Hong Zhou
- Key Laboratory of Meat Processing and Quality Control; Ministry of Education; College of Food Science and Technology; Nanjing Agricultural University; Nanjing 210095 China
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Nievas F, Bogino P, Sorroche F, Giordano W. Detection, characterization, and biological effect of quorum-sensing signaling molecules in peanut-nodulating bradyrhizobia. SENSORS 2012; 12:2851-73. [PMID: 22736981 PMCID: PMC3376631 DOI: 10.3390/s120302851] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/11/2012] [Revised: 02/23/2012] [Accepted: 02/23/2012] [Indexed: 11/16/2022]
Abstract
Bacteria of the genus Bradyrhizobium are able to establish a symbiotic relationship with peanut (Arachis hypogaea) root cells and to fix atmospheric nitrogen by converting it to nitrogenous compounds. Quorum sensing (QS) is a cell-cell communication mechanism employed by a variety of bacterial species to coordinate behavior at a community level through regulation of gene expression. The QS process depends on bacterial production of various signaling molecules, among which the N-acylhomoserine lactones (AHLs) are most commonly used by Gram-negative bacteria. Some previous reports have shown the production of QS signaling molecules by various rhizobia, but little is known regarding mechanisms of communication among peanut-nodulating strains. The aims of this study were to identify and characterize QS signals produced by peanut-nodulating bradyrhizobial strains and to evaluate their effects on processes related to cell interaction. Detection of AHLs in 53 rhizobial strains was performed using the biosensor strains Agrobacterium tumefaciens NTL4 (pZLR4) and Chromobacterium violaceum CV026 for AHLs with long and short acyl chains, respectively. None of the strains screened were found to produce AHLs with short acyl chains, but 14 strains produced AHLs with long acyl chains. These 14 AHL-producing strains were further studied by quantification of β-galactosidase activity levels (AHL-like inducer activity) in NTL4 (pZLR4). Strains displaying moderate to high levels of AHL-like inducer activity were subjected to chemical identification of signaling molecules by high-performance liquid chromatography coupled to mass spectrometry (LC-MS/MS). For each AHL-producing strain, we found at least four different AHLs, corresponding to N-hexanoyl-dl-homoserine lactone (C6), N-(3-oxodecanoyl)-l-homoserine lactone (3OC10), N-(3-oxododecanoyl)-l-homoserine lactone (3OC12), and N-(3-oxotetradecanoyl)-l-homoserine lactone (3OC14). Biological roles of 3OC10, 3OC12, and 3OC14 AHLs were evaluated in both AHL-producing and -non-producing peanut-nodulating strains. Bacterial processes related to survival and nodulation, including motility, biofilm formation, and cell aggregation, were affected or modified by the exogenous addition of increasing concentrations of synthetic AHLs. Our results clearly demonstrate the existence of cell communication mechanisms among bradyrhizobial strains symbiotic of peanut. AHLs with long acyl chains appear to be signaling molecules regulating important QS physiological processes in these bacteria.
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Affiliation(s)
- Fiorela Nievas
- Departamento de Biología Molecular, Facultad de Ciencias Exactas, Físico-Químicas y Naturales, Universidad Nacional de Río Cuarto, Río Cuarto, Córdoba, Argentina.
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Lindemann A, Pessi G, Schaefer AL, Mattmann ME, Christensen QH, Kessler A, Hennecke H, Blackwell HE, Greenberg EP, Harwood CS. Isovaleryl-homoserine lactone, an unusual branched-chain quorum-sensing signal from the soybean symbiont Bradyrhizobium japonicum. Proc Natl Acad Sci U S A 2011; 108:16765-70. [PMID: 21949379 PMCID: PMC3189028 DOI: 10.1073/pnas.1114125108] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many species of Proteobacteria communicate by using LuxI-LuxR-type quorum-sensing systems that produce and detect acyl-homoserine lactone (acyl-HSL) signals. Most of the known signals are straight-chain fatty acyl-HSLs, and evidence indicates that LuxI homologs prefer fatty acid-acyl carrier protein (ACP) over fatty acyl-CoA as the acyl substrate for signal synthesis. Two related LuxI homologs, RpaI and BtaI from Rhodopseudomonas palustris and photosynthetic stem-nodulating bradyrhizobia, direct production of the aryl-HSLs p-coumaroyl-HSL and cinnamoyl-HSL, respectively. Here we report that BjaI from the soybean symbiont Bradyrhizobium japonicum USDA110 is closely related to RpaI and BtaI and catalyzes the synthesis of isovaleryl-HSL (IV-HSL), a branched-chain fatty acyl-HSL. We show that IV-HSL induces expression of bjaI, and in this way IV-HSL functions like many other acyl-HSL quorum-sensing signals. Purified histidine-tagged BjaI was an IV-HSL synthase, which was active with isovaleryl-CoA but not detectably so with isovaleryl-ACP. This suggests that the RpaI-BtaI-BjaI subfamily of acyl-HSL synthases may use CoA- rather than ACP-linked substrates for acyl-HSL synthesis. The bjaI-linked bjaR(1) gene is involved in the response to IV-HSL, and BjaR(1) is sensitive to IV-HSL at concentrations as low as 10 pM. Low but sufficient levels of IV-HSL (about 5 nM) accumulate in B. japonicum culture fluid. The low levels of IV-HSL synthesis have likely contributed to the fact that the quorum-sensing signal from this bacterium has not been described elsewhere.
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Affiliation(s)
- Andrea Lindemann
- Department of Microbiology, University of Washington, Seattle, WA 98195
| | - Gabriella Pessi
- Institute of Microbiology, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Amy L. Schaefer
- Department of Microbiology, University of Washington, Seattle, WA 98195
| | | | | | - Aline Kessler
- Institute of Microbiology, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Hauke Hennecke
- Institute of Microbiology, Swiss Federal Institute of Technology, 8093 Zurich, Switzerland
| | - Helen E. Blackwell
- Department of Chemistry, University of Wisconsin, Madison, WI 53706; and
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Dessaux Y, Chapelle E, Faure D. Quorum Sensing and Quorum Quenching in Soil Ecosystems. SOIL BIOLOGY 2011. [DOI: 10.1007/978-3-642-14512-4_13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Nazir R, Warmink JA, Boersma H, van Elsas JD. Mechanisms that promote bacterial fitness in fungal-affected soil microhabitats. FEMS Microbiol Ecol 2010; 71:169-85. [DOI: 10.1111/j.1574-6941.2009.00807.x] [Citation(s) in RCA: 150] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
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Downie JA. The roles of extracellular proteins, polysaccharides and signals in the interactions of rhizobia with legume roots. FEMS Microbiol Rev 2009; 34:150-70. [PMID: 20070373 DOI: 10.1111/j.1574-6976.2009.00205.x] [Citation(s) in RCA: 219] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Rhizobia adopt many different lifestyles including survival in soil, growth in the rhizosphere, attachment to root hairs and infection and growth within legume roots, both in infection threads and in nodules where they fix nitrogen. They are actively involved in extracellular signalling to their host legumes to initiate infection and nodule morphogenesis. Rhizobia also use quorum-sensing gene regulation via N-acyl-homoserine lactone signals and this can enhance their interaction with legumes as well as their survival under stress and their ability to induce conjugation of plasmids and symbiotic islands, thereby spreading their symbiotic capacity. They produce several surface polysaccharides that are critical for attachment and biofilm formation; some of these polysaccharides are specific for their growth on root hairs and can considerably enhance their ability to infect their host legumes. Different rhizobia use several different types of protein secretion mechanisms (Types I, III, IV, V and VI), and many of the secreted proteins play an important role in their interaction with plants. This review summarizes many of the aspects of the extracellular biology of rhizobia, in particular in relation to their symbiotic interaction with legumes.
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Bonfante P, Anca IA. Plants, Mycorrhizal Fungi, and Bacteria: A Network of Interactions. Annu Rev Microbiol 2009; 63:363-83. [DOI: 10.1146/annurev.micro.091208.073504] [Citation(s) in RCA: 532] [Impact Index Per Article: 35.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Paola Bonfante
- Dipartimento di Biologia Vegetale dell' Università di Torino and Istituto di Protezione delle Piante del CNR, Sezione di Torino, 10125 Torino, Italy;
| | - Iulia-Andra Anca
- Dipartimento di Biologia Vegetale dell' Università di Torino and Istituto di Protezione delle Piante del CNR, Sezione di Torino, 10125 Torino, Italy;
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Abstract
This review describes secondary metabolites that have been shown to be synthesized by symbiotic bacteria, or for which this possibility has been discussed. It includes 365 references.
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Affiliation(s)
- Jörn Piel
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Str. 1, 53121 Bonn, Germany.
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Jitacksorn S, Sadowsky MJ. Nodulation gene regulation and quorum sensing control density-dependent suppression and restriction of nodulation in the Bradyrhizobium japonicum-soybean symbiosis. Appl Environ Microbiol 2008; 74:3749-56. [PMID: 18441104 PMCID: PMC2446537 DOI: 10.1128/aem.02939-07] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2007] [Accepted: 04/21/2008] [Indexed: 11/20/2022] Open
Abstract
The nodulation of Glycine max cv. Lambert and the nodulation-restricting plant introduction (PI) genotype PI 417566 by wild-type Bradyrhizobium japonicum USDA110 is regulated in a population-density-dependent manner. Nodulation on both plant genotypes was suppressed (inhibited) when plants received a high-density inoculum (10(9) cells/ml) of strain USDA110 grown in complex medium, and more nodules were produced on plants receiving a low-cell-density inoculum (10(5) cells/ml). Since cell-free supernatants from strain USDA110 grown to high cell density in complex medium decreased the expression of an nodY-lacZ fusion, this phenomenon was attributed to bradyoxetin-induced repression of nod gene expression. Inoculation of either the permissive soybean genotype (cv. Lambert) or PI 417566 with 10(9) cells/ml of the nodD2, nolA, nodW, and nwsB mutants of USDA110 enhanced nodulation (up to 24%) relative to that seen with inoculations done with 10(5) cells/ml of the mutants or the wild-type strain, indicating that these genes are involved in population-density-dependent nodulation of soybeans. In contrast, the number of nodules produced by an nodD1 mutant on either soybean genotype was less than those seen with the wild-type strain inoculated at a low inoculum density. The nodD2 mutant outcompeted B. japonicum strain USDA123 for nodulation of G. max cv. Lambert at a high or low inoculum density, and the results of root-tip-marking and time-to-nodulate studies indicated that the nolA and nodD2 mutants nodulated this soybean genotype faster than wild-type USDA110. Taken together, the results from these studies indicate that the nodD2 mutant of B. japonicum may be useful to enhance soybean nodulation at high inoculum densities and that NodD2 is a key repressor influencing host-controlled restriction of nodulation, density-dependent suppression of nodulation, perception of bradyoxetin, and competitiveness in the soybean-B. japonicum symbiosis.
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Affiliation(s)
- Siriluck Jitacksorn
- University of Minnesota, Department of Soil, Water, and Climate, University of Minnesota, St. Paul, MN 55108, USA
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Sanchez-Contreras M, Bauer WD, Gao M, Robinson JB, Allan Downie J. Quorum-sensing regulation in rhizobia and its role in symbiotic interactions with legumes. Philos Trans R Soc Lond B Biol Sci 2007; 362:1149-63. [PMID: 17360278 PMCID: PMC2435579 DOI: 10.1098/rstb.2007.2041] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Legume-nodulating bacteria (rhizobia) usually produce N-acyl homoserine lactones, which regulate the induction of gene expression in a quorum-sensing (or population-density)-dependent manner. There is significant diversity in the types of quorum-sensing regulatory systems that are present in different rhizobia and no two independent isolates worked on in detail have the same complement of quorum-sensing genes. The genes regulated by quorum sensing appear to be rather diverse and many are associated with adaptive aspects of physiology that are probably important in the rhizosphere. It is evident that some aspects of rhizobial physiology related to the interaction between rhizobia and legumes are influenced by quorum sensing. However, it also appears that the legumes play an active role, both in terms of interfering with the rhizobial quorum-sensing systems and responding to the signalling molecules made by the bacteria. In this article, we review the diversity of quorum-sensing regulation in rhizobia and the potential role of legumes in influencing and responding to this signalling system.
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