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Zhong C, Hu G, Hu C, Xu C, Zhang Z, Ning K. Comparative genomics analysis reveals genetic characteristics and nitrogen fixation profile of Bradyrhizobium. iScience 2024; 27:108948. [PMID: 38322985 PMCID: PMC10845061 DOI: 10.1016/j.isci.2024.108948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Revised: 09/12/2023] [Accepted: 01/15/2024] [Indexed: 02/08/2024] Open
Abstract
Bradyrhizobium is a genus of nitrogen-fixing bacteria, with some species producing nodules in leguminous plants. Investigations into Bradyrhizobium have recently revealed its substantial genetic resources and agricultural benefits, but a comprehensive survey of its genetic diversity and functional properties is lacking. Using a panel of various strains (N = 278), this study performed a comparative genomics analysis to anticipate genes linked with symbiotic nitrogen fixation. Bradyrhizobium's pan-genome consisted of 84,078 gene families, containing 824 core genes and 42,409 accessory genes. Core genes were mainly involved in crucial cell processes, while accessory genes served diverse functions, including nitrogen fixation and nodulation. Three distinct genetic profiles were identified based on the presence/absence of gene clusters related to nodulation, nitrogen fixation, and secretion systems. Most Bradyrhizobium strains from soil and non-leguminous plants lacked major nif/nod genes and were evolutionarily more closely related. These findings shed light on Bradyrhizobium's genetic features for symbiotic nitrogen fixation.
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Affiliation(s)
- Chaofang Zhong
- Key Laboratory of Wildlife Evolution and Conservation in Mountain Ecosystem of Guangxi, College of Environmental and Life Sciences, Nanning Normal University, Nanning 530001, China
| | - Gang Hu
- Key Laboratory of Wildlife Evolution and Conservation in Mountain Ecosystem of Guangxi, College of Environmental and Life Sciences, Nanning Normal University, Nanning 530001, China
| | - Cong Hu
- Key Laboratory of Wildlife Evolution and Conservation in Mountain Ecosystem of Guangxi, College of Environmental and Life Sciences, Nanning Normal University, Nanning 530001, China
| | - Chaohao Xu
- Key Laboratory of Wildlife Evolution and Conservation in Mountain Ecosystem of Guangxi, College of Environmental and Life Sciences, Nanning Normal University, Nanning 530001, China
| | - Zhonghua Zhang
- Key Laboratory of Wildlife Evolution and Conservation in Mountain Ecosystem of Guangxi, College of Environmental and Life Sciences, Nanning Normal University, Nanning 530001, China
| | - Kang Ning
- Key Laboratory of Molecular Biophysics of the Ministry of Education, Hubei Key Laboratory of Bioinformatics and Molecular-imaging, Department of Bioinformatics and Systems Biology, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
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Van Dingenen J, Garcia Mendez S, Beirinckx S, Vlaminck L, De Keyser A, Stuer N, Verschaete S, Clarysse A, Pannecoucque J, Rombauts S, Roldan-Ruiz I, Willems A, Goormachtig S. Flemish soils contain rhizobia partners for Northwestern Europe-adapted soybean cultivars. Environ Microbiol 2022; 24:3334-3354. [PMID: 35212122 DOI: 10.1111/1462-2920.15941] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Revised: 02/09/2022] [Accepted: 02/12/2022] [Indexed: 11/28/2022]
Abstract
In Europe, soybean (Glycine max) used for food and feed has to be imported, causing negative socioeconomic and environmental impacts. To increase the local production, breeding generated varieties that grow in colder climates, but the yield using the commercial inoculants is not satisfactory in Belgium because of variable nodulation efficiencies. To look for indigenous nodulating strains possibly adapted to the local environment, we initiated a nodulation trap by growing early-maturing cultivars under natural and greenhouse conditions in 107 garden soils in Flanders. Nodules occurred in 18 and 21 soils in the garden and greenhouse experiments respectively. By combining 16S rRNA PCR on single isolates with HiSeq 16S metabarcoding on nodules, we found a large bacterial richness and diversity from different soils. Furthermore, using Oxford Nanopore Technologies sequencing of DNA from one nodule, we retrieved the entire genome of a Bradyrhizobium species, not previously isolated, but profusely present in that nodule. These data highlight the need of combining diverse identification techniques to capture the true nodule rhizobial community. Eight selected rhizobial isolates were subdivided by whole-genome analysis in three genera containing six genetically distinct species that, except for two, aligned with known type strains and were all able to nodulate soybean in the laboratory.
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Affiliation(s)
- Judith Van Dingenen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
- Center for Plant Systems Biology, VIB, Ghent, 9052, Belgium
| | - Sonia Garcia Mendez
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
- Center for Plant Systems Biology, VIB, Ghent, 9052, Belgium
- Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, Ghent, 9000, Belgium
| | - Stien Beirinckx
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
- Center for Plant Systems Biology, VIB, Ghent, 9052, Belgium
| | - Lena Vlaminck
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
- Center for Plant Systems Biology, VIB, Ghent, 9052, Belgium
| | - Annick De Keyser
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
- Center for Plant Systems Biology, VIB, Ghent, 9052, Belgium
| | - Naomi Stuer
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
- Center for Plant Systems Biology, VIB, Ghent, 9052, Belgium
| | - Severine Verschaete
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
- Center for Plant Systems Biology, VIB, Ghent, 9052, Belgium
| | - Alexander Clarysse
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
- Center for Plant Systems Biology, VIB, Ghent, 9052, Belgium
| | - Joke Pannecoucque
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Plant Sciences Unit, Merelbeke, 9820, Belgium
| | - Stephane Rombauts
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
- Center for Plant Systems Biology, VIB, Ghent, 9052, Belgium
| | - Isabel Roldan-Ruiz
- Flanders Research Institute for Agriculture, Fisheries and Food (ILVO), Plant Sciences Unit, Merelbeke, 9820, Belgium
| | - Anne Willems
- Department of Biochemistry and Microbiology, Faculty of Sciences, Ghent University, Ghent, 9000, Belgium
| | - Sofie Goormachtig
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, 9052, Belgium
- Center for Plant Systems Biology, VIB, Ghent, 9052, Belgium
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Avontuur JR, Palmer M, Beukes CW, Chan WY, Tasiya T, van Zyl E, Coetzee MPA, Stepkowski T, Venter SN, Steenkamp ET. Bradyrhizobium altum sp. nov., Bradyrhizobium oropedii sp. nov. and Bradyrhizobium acaciae sp. nov. from South Africa show locally restricted and pantropical nodA phylogeographic patterns. Mol Phylogenet Evol 2021; 167:107338. [PMID: 34757168 DOI: 10.1016/j.ympev.2021.107338] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 09/22/2021] [Accepted: 10/27/2021] [Indexed: 10/20/2022]
Abstract
Africa is known for its rich legume diversity with a significant number of endemic species originating in South Africa. Many of these legumes associate with rhizobial symbionts of the genus Bradyrhizobium, of which most represent new species. Yet, none of the Bradyrhizobium species from South Africa have been described. In this study, phylogenetic analysis of 16S rRNA gene sequences of fourteen strains isolated in southern Africa from root nodules of diverse legumes (i.e., from the tribes Crotalarieae, Acacieae, Genisteae, Phaseoleae and Cassieae) revealed that they belong to the Bradyrhizobium elkanii supergroup. The taxonomic position and possible novelty of these strains were further interrogated using genealogical concordance of five housekeeping genes (atpD, dnaK, glnII, gyrB and rpoB). These phylogenies consistently recovered four monophyletic groups and one singleton within Bradyrhizobium. Of these groups, two were conspecific with Bradyrhizobium brasilense UFLA 03-321T and Bradyrhizobium ivorense CI-1BT, while the remaining three represented novel taxa. Their existence was further supported with genome data, as well as metabolic and physiological traits. Analysis of nodA gene sequences further showed that the evolution of these bacteria likely involved adapting to local legume hosts and environmental conditions through the acquisition, via horizontal gene transfer, of optimal symbiotic loci. We accordingly propose the following names Bradyrhizobium acaciae sp. nov. 10BBT (SARCC 730T = LMG 31409T), Bradyrhizobium oropedii sp. nov. Pear76T (SARCC 731T = LMG 31408T), and Bradyrhizobium altum sp. nov. Pear77T (SARCC 754T = LMG 31407T) to accommodate three novel species, all of which are symbionts of legumes in South Africa.
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Affiliation(s)
- Juanita R Avontuur
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Marike Palmer
- School of Life Sciences, University of Nevada, Las Vegas, Nevada, United States
| | - Chrizelle W Beukes
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Wai Y Chan
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa; National Institute for Communicable Disease, National Health Laboratory Service, Johannesburg, South Africa
| | - Taponeswa Tasiya
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Elritha van Zyl
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Martin P A Coetzee
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
| | - Tomasz Stepkowski
- Department of Biochemistry and Microbiology, Institute of Biology, Warsaw University of Life Sciences (SGGW), Poland
| | - Stephanus N Venter
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa.
| | - Emma T Steenkamp
- Department of Biochemistry, Genetics and Microbiology (BGM), Forestry and Agricultural Biotechnology Institute (FABI), University of Pretoria, Pretoria, South Africa
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Bromfield ESP, Cloutier S. Bradyrhizobium septentrionale sp. nov. (sv. septentrionale) and Bradyrhizobium quebecense sp. nov. (sv. septentrionale) associated with legumes native to Canada possess rearranged symbiosis genes and numerous insertion sequences. Int J Syst Evol Microbiol 2021; 71. [PMID: 34106824 PMCID: PMC8374602 DOI: 10.1099/ijsem.0.004831] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Six bacterial strains isolated from root nodules of soybean plants that had been inoculated with root-zone soil of legumes native to Canada were previously characterized and 1) placed in two novel lineages within the genus Bradyrhizobium and 2) assigned to symbiovar septentrionale. Here we verified the taxonomic status of these strains using genomic and phenotypic analyses. Phylogenetic analyses of five protein encoding partial gene sequences as well as 52 full length ribosome protein subunit gene sequences confirmed placement of the novel strains in two highly supported lineages distinct from named Bradyrhizobium species. The highest average nucleotide identity values of strains representing these two lineages relative to type strains of closest relatives were 90.7 and 92.3% which is well below the threshold value for bacterial species circumscription. The genomes of representative strains 1S1T, 162S2 and 66S1MBT have sizes of 10598256, 10733150 and 9032145 bp with DNA G+C contents of 63.5, 63.4 and 63.8 mol%, respectively. These strains possess between one and three plasmids based on copy number of plasmid replication and segregation (repABC) genes. Novel strains also possess numerous insertion sequences, and, relative to reference strain Bradyrhizobium diazoefficiens USDA110T, exhibit inversion and fragmentation of nodulation (nod) and nitrogen-fixation (nif) gene clusters. Phylogenetic analyses of nodC and nifH gene sequences confirmed placement of novel strains in a distinct lineage corresponding to symbiovar septentrionale. Data for morphological, physiological and symbiotic characteristics complement the sequence-based results. The data presented here support the description of two new species for which the names Bradyrhizobium septentrionale sp. nov. (sv. septentrionale) and Bradyrhizobium quebecense sp. nov. (sv. septentrionale) are proposed, with 1S1T (=LMG 29930T=HAMBI 3676T) and 66S1MBT (=LMG 31547T=HAMBI 3720T) as type strains, respectively.
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Affiliation(s)
- Eden S P Bromfield
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario K1A OC6, Canada
| | - Sylvie Cloutier
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario K1A OC6, Canada
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Wasai-Hara S, Minamisawa K, Cloutier S, Bromfield ESP. Strains of Bradyrhizobium cosmicum sp. nov., isolated from contrasting habitats in Japan and Canada possess photosynthesis gene clusters with the hallmark of genomic islands. Int J Syst Evol Microbiol 2020; 70:5063-5074. [PMID: 32804606 PMCID: PMC7656271 DOI: 10.1099/ijsem.0.004380] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/24/2020] [Indexed: 12/28/2022] Open
Abstract
The taxonomic status of two previously characterized Bradyrhizobium strains (58S1T and S23321) isolated from contrasting habitats in Canada and Japan was verified by genomic and phenotypic analyses. Phylogenetic analyses of five and 27 concatenated protein-encoding core gene sequences placed both strains in a highly supported lineage distinct from named species in the genus Bradyrhizobium with Bradyrhizobium betae as the closest relative. Average nucleotide identity values of genome sequences between the test and reference strains were between 84.5 and 94.2 %, which is below the threshold value for bacterial species circumscription. The complete genomes of strains 58S1T and S23321 consist of single chromosomes of 7.30 and 7.23 Mbp, respectively, and do not have symbiosis islands. The genomes of both strains have a G+C content of 64.3 mol%. Present in the genome of these strains is a photosynthesis gene cluster (PGC) containing key photosynthesis genes. A tRNA gene and its partial tandem duplication were found at the boundaries of the PGC region in both strains, which is likely the hallmark of genomic island insertion. Key nitrogen-fixation genes were detected in the genomes of both strains, but nodulation and type III secretion system genes were not found. Sequence analysis of the nitrogen fixation gene, nifH, placed 58S1T and S23321 in a novel lineage distinct from described Bradyrhizobium species. Data for phenotypic tests, including growth characteristics and carbon source utilization, supported the sequence-based analyses. Based on the data presented here, a novel species with the name Bradyrhizobium cosmicum sp. nov. is proposed with 58S1T (=LMG 31545T=HAMBI 3725T) as the type strain.
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Affiliation(s)
- Sawa Wasai-Hara
- Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980–8577, Japan
| | - Kiwamu Minamisawa
- Graduate School of Life Sciences, Tohoku University, Katahira, Aoba-ku, Sendai 980–8577, Japan
| | - Sylvie Cloutier
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario K1A OC6, Canada
| | - Eden S. P. Bromfield
- Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, 960 Carling Avenue, Ottawa, Ontario K1A OC6, Canada
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de Lajudie P, Young JPW. International Committee on Systematics of Prokaryotes Subcommittee on the Taxonomy of Rhizobia and Agrobacteria Minutes of the closed meeting by videoconference, 17 July 2019. Int J Syst Evol Microbiol 2020; 70:3563-3571. [DOI: 10.1099/ijsem.0.004157] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Minutes of the closed meeting of the ICSP Subcommittee on the Taxonomy of Rhizobia and Agrobacteria held by videoconference on 17 July 2019, and list of recent species.
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Analysis of the Complete Genome Sequence of the Widely Studied Strain Bradyrhizobium betae PL7HG1 T Reveals the Presence of Photosynthesis Genes and a Putative Plasmid. Microbiol Resour Announc 2019; 8:8/46/e01282-19. [PMID: 31727720 PMCID: PMC6856286 DOI: 10.1128/mra.01282-19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Here, we present the complete genome sequence of the widely studied strain Bradyrhizobium betae PL7HG1T, isolated from a tumor on the roots of sugar beet. The genome consists of a 7.2-Mbp circular chromosome containing key photosynthesis genes but not genes for nodulation and nitrogen fixation. A putative plasmid was also detected. Here, we present the complete genome sequence of the widely studied strain Bradyrhizobium betae PL7HG1T, isolated from a tumor on the roots of sugar beet. The genome consists of a 7.2-Mbp circular chromosome containing key photosynthesis genes but not genes for nodulation and nitrogen fixation. A putative plasmid was also detected.
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