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Khanal A, Han SR, Lee JH, Oh TJ. Comparative Genome Analysis of Polar Mesorhizobium sp. PAMC28654 to Gain Insight into Tolerance to Salinity and Trace Element Stress. Microorganisms 2024; 12:120. [PMID: 38257947 PMCID: PMC10820077 DOI: 10.3390/microorganisms12010120] [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: 11/01/2023] [Revised: 01/04/2024] [Accepted: 01/04/2024] [Indexed: 01/24/2024] Open
Abstract
In this study, Mesorhizobium sp. PAMC28654 was isolated from a soil sample collected from the polar region of Uganda. Whole-genome sequencing and comparative genomics were performed to better understand the genomic features necessary for Mesorhizobium sp. PAMC28654 to survive and thrive in extreme conditions and stresses. Additionally, diverse sequence analysis tools were employed for genomic investigation. The results of the analysis were then validated using wet-lab experiments. Genome analysis showed trace elements' resistant proteins (CopC, CopD, CzcD, and Acr3), exopolysaccharide (EPS)-producing proteins (ExoF and ExoQ), and nitrogen metabolic proteins (NarG, NarH, and NarI). The strain was positive for nitrate reduction. It was tolerant to 100 mM NaCl at 15 °C and 25 °C temperatures and resistant to multiple trace elements (up to 1 mM CuSO4·5H2O, 2 mM CoCl2·6H2O, 1 mM ZnSO4·7H2O, 0.05 mM Cd(NO3)2·4H2O, and 100 mM Na2HAsO4·7H2O at 15 °C and 0.25 mM CuSO4·5H2O, 2 mM CoCl2·6H2O, 0.5 mM ZnSO4·7H2O, 0.01 mM Cd(NO3)2·4H2O, and 100 mM Na2HAsO4·7H2O at 25 °C). This research contributes to our understanding of bacteria's ability to survive abiotic stresses. The isolated strain can be a potential candidate for implementation for environmental and agricultural purposes.
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Affiliation(s)
- Anamika Khanal
- Genome-Based Bio-IT Convergence Institute, Asan 31460, Republic of Korea; (A.K.); (S.-R.H.)
- Bio Big Data-Based Chungnam Smart Clean Research Leader Training Program, SunMoon University, Asan 31460, Republic of Korea
| | - So-Ra Han
- Genome-Based Bio-IT Convergence Institute, Asan 31460, Republic of Korea; (A.K.); (S.-R.H.)
- Bio Big Data-Based Chungnam Smart Clean Research Leader Training Program, SunMoon University, Asan 31460, Republic of Korea
- Department of Life Science and Biochemical Engineering, Graduate School, SunMoon University, Asan 31460, Republic of Korea
| | - Jun Hyuck Lee
- Research Unit of Cryogenic Novel Materials, Korea Polar Research Institute, Incheon 21990, Republic of Korea;
| | - Tae-Jin Oh
- Genome-Based Bio-IT Convergence Institute, Asan 31460, Republic of Korea; (A.K.); (S.-R.H.)
- Bio Big Data-Based Chungnam Smart Clean Research Leader Training Program, SunMoon University, Asan 31460, Republic of Korea
- Department of Life Science and Biochemical Engineering, Graduate School, SunMoon University, Asan 31460, Republic of Korea
- Department of Pharmaceutical Engineering and Biotechnology, SunMoon University, Asan 31460, Republic of Korea
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Colombi E, Hill Y, Lines R, Sullivan JT, Kohlmeier MG, Christophersen CT, Ronson CW, Terpolilli JJ, Ramsay JP. Population genomics of Australian indigenous Mesorhizobium reveals diverse nonsymbiotic genospecies capable of nitrogen-fixing symbioses following horizontal gene transfer. Microb Genom 2023; 9:mgen000918. [PMID: 36748564 PMCID: PMC9973854 DOI: 10.1099/mgen.0.000918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Mesorhizobia are soil bacteria that establish nitrogen-fixing symbioses with various legumes. Novel symbiotic mesorhizobia frequently evolve following horizontal transfer of symbiosis-gene-carrying integrative and conjugative elements (ICESyms) to indigenous mesorhizobia in soils. Evolved symbionts exhibit a wide range in symbiotic effectiveness, with some fixing nitrogen poorly or not at all. Little is known about the genetic diversity and symbiotic potential of indigenous soil mesorhizobia prior to ICESym acquisition. Here we sequenced genomes of 144 Mesorhizobium spp. strains cultured directly from cultivated and uncultivated Australian soils. Of these, 126 lacked symbiosis genes. The only isolated symbiotic strains were either exotic strains used previously as legume inoculants, or indigenous mesorhizobia that had acquired exotic ICESyms. No native symbiotic strains were identified. Indigenous nonsymbiotic strains formed 22 genospecies with phylogenomic diversity overlapping the diversity of internationally isolated symbiotic Mesorhizobium spp. The genomes of indigenous mesorhizobia exhibited no evidence of prior involvement in nitrogen-fixing symbiosis, yet their core genomes were similar to symbiotic strains and they generally lacked genes for synthesis of biotin, nicotinate and thiamine. Genomes of nonsymbiotic mesorhizobia harboured similar mobile elements to those of symbiotic mesorhizobia, including ICESym-like elements carrying aforementioned vitamin-synthesis genes but lacking symbiosis genes. Diverse indigenous isolates receiving ICESyms through horizontal gene transfer formed effective symbioses with Lotus and Biserrula legumes, indicating most nonsymbiotic mesorhizobia have an innate capacity for nitrogen-fixing symbiosis following ICESym acquisition. Non-fixing ICESym-harbouring strains were isolated sporadically within species alongside effective symbionts, indicating chromosomal lineage does not predict symbiotic potential. Our observations suggest previously observed genomic diversity amongst symbiotic Mesorhizobium spp. represents a fraction of the extant diversity of nonsymbiotic strains. The overlapping phylogeny of symbiotic and nonsymbiotic clades suggests major clades of Mesorhizobium diverged prior to introduction of symbiosis genes and therefore chromosomal genes involved in symbiosis have evolved largely independent of nitrogen-fixing symbiosis.
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Affiliation(s)
- Elena Colombi
- Curtin Medical School, Curtin University, Bentley, Western Australia 6102, Australia.,Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia.,Present address: School of Agriculture and Food, Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Victoria 3010, Australia
| | - Yvette Hill
- Legume Rhizobium Sciences, Food Futures Institute, Murdoch University, 90 South St, Murdoch, Western Australia 6150, Australia
| | - Rose Lines
- Trace and Environmental DNA (TrEnD) Laboratory, School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia
| | - John T Sullivan
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - MacLean G Kohlmeier
- Legume Rhizobium Sciences, Food Futures Institute, Murdoch University, 90 South St, Murdoch, Western Australia 6150, Australia
| | - Claus T Christophersen
- Trace and Environmental DNA (TrEnD) Laboratory, School of Molecular and Life Sciences, Curtin University, Kent Street, Bentley, Western Australia 6102, Australia.,School of Medical & Health Sciences, Edith Cowan University, Joondalup, Western Australia, Australia.,Centre for Integrative Metabolomics and Computational Biology, Edith Cowan University, Joondalup, Western Australia, Australia
| | - Clive W Ronson
- Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
| | - Jason J Terpolilli
- Legume Rhizobium Sciences, Food Futures Institute, Murdoch University, 90 South St, Murdoch, Western Australia 6150, Australia
| | - Joshua P Ramsay
- Curtin Medical School, Curtin University, Bentley, Western Australia 6102, Australia.,Curtin Health Innovation Research Institute, Curtin University, Bentley, Western Australia 6102, Australia
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Tong W, Li X, Wang E, Cao Y, Chen W, Tao S, Wei G. Genomic insight into the origins and evolution of symbiosis genes in Phaseolus vulgaris microsymbionts. BMC Genomics 2020; 21:186. [PMID: 32106817 PMCID: PMC7047383 DOI: 10.1186/s12864-020-6578-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 02/13/2020] [Indexed: 01/02/2023] Open
Abstract
Background Phaseolus vulgaris (common bean) microsymbionts belonging to the bacterial genera Rhizobium, Bradyrhizobium, and Ensifer (Sinorhizobium) have been isolated across the globe. Individual symbiosis genes (e.g., nodC) of these rhizobia can be different within each genus and among distinct genera. Little information is available about the symbiotic structure of indigenous Rhizobium strains nodulating introduced bean plants or the emergence of a symbiotic ability to associate with bean plants in Bradyrhizobium and Ensifer strains. Here, we sequenced the genomes of 29 representative bean microsymbionts (21 Rhizobium, four Ensifer, and four Bradyrhizobium) and compared them with closely related reference strains to estimate the origins of symbiosis genes among these Chinese bean microsymbionts. Results Comparative genomics demonstrated horizontal gene transfer exclusively at the plasmid level, leading to expanded diversity of bean-nodulating Rhizobium strains. Analysis of vertically transferred genes uncovered 191 (out of the 2654) single-copy core genes with phylogenies strictly consistent with the taxonomic status of bacterial species, but none were found on symbiosis plasmids. A common symbiotic region was wholly conserved within the Rhizobium genus yet different from those of the other two genera. A single strain of Ensifer and two Bradyrhizobium strains shared similar gene content with soybean microsymbionts in both chromosomes and symbiotic regions. Conclusions The 19 native bean Rhizobium microsymbionts were assigned to four defined species and six putative novel species. The symbiosis genes of R. phaseoli, R. sophoriradicis, and R. esperanzae strains that originated from Mexican bean-nodulating strains were possibly introduced alongside bean seeds. R. anhuiense strains displayed distinct host ranges, indicating transition into bean microsymbionts. Among the six putative novel species exclusive to China, horizontal transfer of symbiosis genes suggested symbiosis with other indigenous legumes and loss of originally symbiotic regions or non-symbionts before the introduction of common bean into China. Genome data for Ensifer and Bradyrhizobium strains indicated symbiotic compatibility between microsymbionts of common bean and other hosts such as soybean.
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Affiliation(s)
- Wenjun Tong
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Xiangchen Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.,Bioinformatics Center, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Entao Wang
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, 11340, México D.F, Mexico
| | - Ying Cao
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Weimin Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
| | - Shiheng Tao
- Bioinformatics Center, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
| | - Gehong Wei
- State Key Laboratory of Crop Stress Biology for Arid Areas, Shaanxi Key Laboratory of Agricultural and Environmental Microbiology, College of Life Science, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
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Complete Genome Sequence of Mesorhizobium ciceri bv. biserrulae WSM1497, an Efficient Nitrogen-Fixing Microsymbiont of the Forage Legume Biserrula pelecinus. GENOME ANNOUNCEMENTS 2017; 5:5/35/e00902-17. [PMID: 28860254 PMCID: PMC5578852 DOI: 10.1128/genomea.00902-17] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
We report here the complete genome sequence of Mesorhizobium ciceri bv. biserrulae strain WSM1497, the efficient nitrogen-fixing microsymbiont and commercial inoculant in Australia of the forage legume Biserrula pelecinus. The genome consists of 7.2 Mb distributed across a single chromosome (6.67 Mb) and a single plasmid (0.53 Mb).
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Assembly and transfer of tripartite integrative and conjugative genetic elements. Proc Natl Acad Sci U S A 2016; 113:12268-12273. [PMID: 27733511 DOI: 10.1073/pnas.1613358113] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Integrative and conjugative elements (ICEs) are ubiquitous mobile genetic elements present as "genomic islands" within bacterial chromosomes. Symbiosis islands are ICEs that convert nonsymbiotic mesorhizobia into symbionts of legumes. Here we report the discovery of symbiosis ICEs that exist as three separate chromosomal regions when integrated in their hosts, but through recombination assemble as a single circular ICE for conjugative transfer. Whole-genome comparisons revealed exconjugants derived from nonsymbiotic mesorhizobia received three separate chromosomal regions from the donor Mesorhizobium ciceri WSM1271. The three regions were each bordered by two nonhomologous integrase attachment (att) sites, which together comprised three homologous pairs of attL and attR sites. Sequential recombination between each attL and attR pair produced corresponding attP and attB sites and joined the three fragments to produce a single circular ICE, ICEMcSym1271 A plasmid carrying the three attP sites was used to recreate the process of tripartite ICE integration and to confirm the role of integrase genes intS, intM, and intG in this process. Nine additional tripartite ICEs were identified in diverse mesorhizobia and transfer was demonstrated for three of them. The transfer of tripartite ICEs to nonsymbiotic mesorhizobia explains the evolution of competitive but suboptimal N2-fixing strains found in Western Australian soils. The unheralded existence of tripartite ICEs raises the possibility that multipartite elements reside in other organisms, but have been overlooked because of their unusual biology. These discoveries reveal mechanisms by which integrases dramatically manipulate bacterial genomes to allow cotransfer of disparate chromosomal regions.
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