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Van Cauwenberghe J, Simms EL. How might bacteriophages shape biological invasions? mBio 2023; 14:e0188623. [PMID: 37812005 PMCID: PMC10653932 DOI: 10.1128/mbio.01886-23] [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] [Indexed: 10/10/2023] Open
Abstract
Invasions by eukaryotes dependent on environmentally acquired bacterial mutualists are often limited by the ability of bacterial partners to survive and establish free-living populations. Focusing on the model legume-rhizobium mutualism, we apply invasion biology hypotheses to explain how bacteriophages can impact the competitiveness of introduced bacterial mutualists. Predicting how phage-bacteria interactions affect invading eukaryotic hosts requires knowing the eco-evolutionary constraints of introduced and native microbial communities, as well as their differences in abundance and diversity. By synthesizing research from invasion biology, as well as bacterial, viral, and community ecology, we create a conceptual framework for understanding and predicting how phages can affect biological invasions through their effects on bacterial mutualists.
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Affiliation(s)
- Jannick Van Cauwenberghe
- Institute of Biodiversity, Faculty of Biological Sciences, Cluster of Excellence Balance of the Microverse, Friedrich Schiller University Jena, Jena, Germany
- Department of Integrative Biology, University of California, Berkeley, California, USA
| | - Ellen L. Simms
- Department of Integrative Biology, University of California, Berkeley, California, USA
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2
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Young JPW, Jorrin B, Moeskjær S, James EK. Rhizobium brockwellii sp. nov., Rhizobium johnstonii sp. nov. and Rhizobium beringeri sp. nov., three genospecies within the Rhizobium leguminosarum species complex. Int J Syst Evol Microbiol 2023; 73. [PMID: 37486744 DOI: 10.1099/ijsem.0.005979] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2023] Open
Abstract
Genomic evidence indicates that the
Rhizobium leguminosarum
species complex comprises multiple distinct species, perhaps 18 or more. Of the five earliest genospecies (gs) to be described, only two have formal names: R. leguminosarum sensu stricto (gsE) and
Rhizobium ruizarguesonis
(gsC). Here, we provide formal descriptions and names for the other three genospecies, based on the publicly available genome sequences for multiple strains of each species: Rhizobium brockwellii sp. nov. (gsA, 37 strains, type strain CC275eT=LMG 6122T = ICMP 2163T=NZP 561T = PDDCC 2163T=HAMBI 13T), Rhizobium johnstonii sp. nov. (gsB, 54 strains, type strain 3841T = LMG 32736T=DSM 114642T) and Rhizobium beringeri sp. nov. (gsD, 8 strains, type strain SM51T = LMG 32895T = DSM 115206T). Each species forms a well-supported clade in a phylogeny based on 120 concatenated core genes. All strains have average nucleotide identity (ANI) above 96 % with the relevant type strain and below 96 % with all other type strains. Each species is characterised by a number of genes that are absent or rare in other species.
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Affiliation(s)
- J Peter W Young
- Department of Biology, University of York, York YO10 5DD, UK
| | - Beatriz Jorrin
- Department of Biology, University of Oxford, Oxford OX1 3RB, UK
| | - Sara Moeskjær
- School of Biosciences, University of Sheffield, Sheffield S10 2TN, UK
| | - Euan K James
- Ecological Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK
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3
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Riley AB, Grillo MA, Epstein B, Tiffin P, Heath KD. Discordant population structure among rhizobium divided genomes and their legume hosts. Mol Ecol 2023; 32:2646-2659. [PMID: 36161739 DOI: 10.1111/mec.16704] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Revised: 09/15/2022] [Accepted: 09/20/2022] [Indexed: 11/29/2022]
Abstract
Symbiosis often occurs between partners with distinct life history characteristics and dispersal mechanisms. Many bacterial symbionts have genomes comprising multiple replicons with distinct rates of evolution and horizontal transmission. Such differences might drive differences in population structure between hosts and symbionts and among the elements of the divided genomes of bacterial symbionts. These differences might, in turn, shape the evolution of symbiotic interactions and bacterial evolution. Here we use whole genome resequencing of a hierarchically structured sample of 191 strains of Sinorhizobium meliloti collected from 21 locations in southern Europe to characterize population structures of this bacterial symbiont, which forms a root nodule symbiosis with the host plant Medicago truncatula. S. meliloti genomes showed high local (within-site) variation and little isolation by distance. This was particularly true for the two symbiosis elements, pSymA and pSymB, which have population structures that are similar to each other, but distinct from both the bacterial chromosome and the host plant. Given limited recombination on the chromosome, compared to the symbiosis elements, distinct population structures may result from differences in effective gene flow. Alternatively, positive or purifying selection, with little recombination, may explain distinct geographical patterns at the chromosome. Discordant population structure between hosts and symbionts indicates that geographically and genetically distinct host populations in different parts of the range might interact with genetically similar symbionts, potentially minimizing local specialization.
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Affiliation(s)
- Alex B Riley
- Department of Plant Biology, University of Illinois, Urbana, Illinois, USA
| | - Michael A Grillo
- Department of Biology, Loyola University Chicago, Chicago, Illinois, USA
| | - Brendan Epstein
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA
| | - Peter Tiffin
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA
| | - Katy D Heath
- Department of Plant Biology, University of Illinois, Urbana, Illinois, USA
- Carl R. Woese Institute for Genomic Biology, University of Illinois, Urbana, Illinois, USA
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4
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Weith SK, Jahufer MZZ, Hofmann RW, Anderson CB, Luo D, Ehoche OG, Cousins G, Jones EE, Ballard RA, Griffiths AG. Quantitative genetic analysis reveals potential to breed for improved white clover growth in symbiosis with nitrogen-fixing Rhizobium bacteria. FRONTIERS IN PLANT SCIENCE 2022; 13:953400. [PMID: 36212301 PMCID: PMC9534031 DOI: 10.3389/fpls.2022.953400] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 08/08/2022] [Indexed: 06/16/2023]
Abstract
White clover (Trifolium repens) is integral to mixed pastures in New Zealand and temperate agriculture globally. It provides quality feed and a sustainable source of plant-available nitrogen (N) via N-fixation through symbiosis with soil-dwelling Rhizobium bacteria. Improvement of N-fixation in white clover is a route to enhancing sustainability of temperate pasture production. Focussing on seedling growth critical for crop establishment and performance, a population of 120 half-sibling white clover families was assessed with either N-supplementation or N-fixation via inoculation with a commercial Rhizobium strain (TA1). Quantitative genetic analysis identified significant (p < 0.05) family additive genetic variance for Shoot and Root Dry Matter (DM) and Symbiotic Potential (SP), and Root to Shoot ratio. Estimated narrow-sense heritabilities for above-ground symbiotic traits were moderate (0.24-0.33), and the strong (r ≥ 0.97) genetic correlation between Shoot and Root DM indicated strong pleiotropy or close linkage. The moderate (r = 0.47) phenotypic correlation between Shoot DM under symbiosis vs. under N-supplementation suggested plant growth with mineral-N was not a strong predictor of symbiotic performance. At 5% among-family selection pressure, predicted genetic gains per selection cycle of 19 and 17% for symbiotic traits Shoot DM and Shoot SP, respectively, highlighted opportunities for improved early seedling establishment and growth under symbiosis. Single and multi-trait selection methods, including a Smith-Hazel index focussing on an ideotype of high Shoot DM and Shoot SP, showed commonality of top-ranked families among traits. This study provides a platform for proof-of-concept crosses to breed for enhanced seedling growth under Rhizobium symbiosis and is informative for other legume crops.
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Affiliation(s)
- Sean K. Weith
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, New Zealand
| | | | - Rainer W. Hofmann
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, New Zealand
| | - Craig B. Anderson
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
| | - Dongwen Luo
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
| | - O. Grace Ehoche
- AgResearch, Grasslands Research Centre, Palmerston North, New Zealand
- PGG Wrightson Seeds Ltd., Grasslands Research Centre, Palmerston North, New Zealand
| | - Greig Cousins
- PGG Wrightson Seeds Ltd., Grasslands Research Centre, Palmerston North, New Zealand
| | - E. Eirian Jones
- Faculty of Agriculture and Life Sciences, Lincoln University, Lincoln, New Zealand
| | - Ross A. Ballard
- South Australian Research and Development Institute (SARDI), Adelaide, SA, Australia
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5
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Batstone RT. Genomes within genomes: nested symbiosis and its implications for plant evolution. THE NEW PHYTOLOGIST 2022; 234:28-34. [PMID: 34761378 DOI: 10.1111/nph.17847] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Accepted: 10/20/2021] [Indexed: 06/13/2023]
Abstract
Many important plant traits are products of nested symbiosis: mobile genetic elements (MGEs) are nested within microbes, which in turn, are nested within plants. Plant trait variation is therefore not only determined by the plant's genome, but also by loci within microbes and MGEs. Yet it remains unclear how interactions and coevolution within nested symbiosis impacts the evolution of plant traits. Despite the complexities of nested symbiosis, including nonadditive interactions, understanding the evolution of plant traits is facilitated by combining quantitative genetic and functional genomic approaches that explicitly consider sources of nested genetic variation (from loci in MGEs to microbiomes). Additionally, understanding coevolution within nested symbiosis enables us to design or select for MGEs that promote plant health.
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Affiliation(s)
- Rebecca T Batstone
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, 1206 West Gregory Drive, Urbana, IL, 61801, USA
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6
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Tanoeiro L, Oleastro M, Nunes A, Marques AT, Duarte SV, Gomes JP, Matos APA, Vítor JMB, Vale FF. Cryptic Prophages Contribution for Campylobacter jejuni and Campylobacter coli Introgression. Microorganisms 2022; 10:microorganisms10030516. [PMID: 35336092 PMCID: PMC8955182 DOI: 10.3390/microorganisms10030516] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Revised: 02/22/2022] [Accepted: 02/23/2022] [Indexed: 11/23/2022] Open
Abstract
Campylobacter coli and C. jejuni, the causing agents of campylobacteriosis, are described to be undergoing introgression events, i.e., the transference of genetic material between different species, with some isolates sharing almost a quarter of its genome. The participation of phages in introgression events and consequent impact on host ecology and evolution remain elusive. Three distinct prophages, named C. jejuni integrated elements 1, 2, and 4 (CJIE1, CJIE2, and CJIE4), are described in C. jejuni. Here, we identified two unreported prophages, Campylobacter coli integrated elements 1 and 2 (CCIE1 and CCIE2 prophages), which are C. coli homologues of CJIE1 and CJIE2, respectively. No induction was achieved for both prophages. Conversely, induction assays on CJIE1 and CJIE2 point towards the inducibility of these prophages. CCIE2-, CJIE1-, and CJIE4-like prophages were identified in a Campylobacter spp. population of 840 genomes, and phylogenetic analysis revealed clustering in three major groups: CJIE1-CCIE1, CJIE2-CCIE2, and CJIE4, clearly segregating prophages from C. jejuni and C. coli, but not from human- and nonhuman-derived isolates, corroborating the flowing between animals and humans in the agricultural context. Punctual bacteriophage host-jumps were observed in the context of C. jejuni and C. coli, and although random chance cannot be fully discarded, these observations seem to implicate prophages in evolutionary introgression events that are modulating the hybridization of C. jejuni and C. coli species.
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Affiliation(s)
- Luís Tanoeiro
- Pathogen Genome Bioinformatics and Computational Biology, Research Institute for Medicines (iMed-ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal; (L.T.); (A.T.M.); (J.M.B.V.)
| | - Mónica Oleastro
- National Reference Laboratory for Gastrointestinal Infections, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, 1600-609 Lisboa, Portugal;
| | - Alexandra Nunes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, 1600-609 Lisboa, Portugal; (A.N.); (J.P.G.)
| | - Andreia T. Marques
- Pathogen Genome Bioinformatics and Computational Biology, Research Institute for Medicines (iMed-ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal; (L.T.); (A.T.M.); (J.M.B.V.)
| | - Sílvia Vaz Duarte
- Innovation and Technology Unit, Department of Human Genetics, National Institute of Health Dr. Ricardo Jorge, 1600-609 Lisboa, Portugal;
| | - João Paulo Gomes
- Bioinformatics Unit, Department of Infectious Diseases, National Institute of Health Dr. Ricardo Jorge, 1600-609 Lisboa, Portugal; (A.N.); (J.P.G.)
| | - António Pedro Alves Matos
- Centro de Investigação Interdisciplinar Egas Moniz (CiiEM), Cooperativa de Ensino Superior Egas Moniz, Quinta da Granja, 2829-511 Caparica, Portugal;
| | - Jorge M. B. Vítor
- Pathogen Genome Bioinformatics and Computational Biology, Research Institute for Medicines (iMed-ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal; (L.T.); (A.T.M.); (J.M.B.V.)
| | - Filipa F. Vale
- Pathogen Genome Bioinformatics and Computational Biology, Research Institute for Medicines (iMed-ULisboa), Faculty of Pharmacy, Universidade de Lisboa, 1649-003 Lisboa, Portugal; (L.T.); (A.T.M.); (J.M.B.V.)
- Correspondence: or
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7
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Wardell GE, Hynes MF, Young PJ, Harrison E. Why are rhizobial symbiosis genes mobile? Philos Trans R Soc Lond B Biol Sci 2022; 377:20200471. [PMID: 34839705 PMCID: PMC8628070 DOI: 10.1098/rstb.2020.0471] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Accepted: 07/28/2021] [Indexed: 11/12/2022] Open
Abstract
Rhizobia are one of the most important and best studied groups of bacterial symbionts. They are defined by their ability to establish nitrogen-fixing intracellular infections within plant hosts. One surprising feature of this symbiosis is that the bacterial genes required for this complex trait are not fixed within the chromosome, but are encoded on mobile genetic elements (MGEs), namely plasmids or integrative and conjugative elements. Evidence suggests that many of these elements are actively mobilizing within rhizobial populations, suggesting that regular symbiosis gene transfer is part of the ecology of rhizobial symbionts. At first glance, this is counterintuitive. The symbiosis trait is highly complex, multipartite and tightly coevolved with the legume hosts, while transfer of genes can be costly and disrupt coadaptation between the chromosome and the symbiosis genes. However, horizontal gene transfer is a process driven not only by the interests of the host bacterium, but also, and perhaps predominantly, by the interests of the MGEs that facilitate it. Thus understanding the role of horizontal gene transfer in the rhizobium-legume symbiosis requires a 'mobile genetic element's-eye view' on the ecology and evolution of this important symbiosis. This article is part of the theme issue 'The secret lives of microbial mobile genetic elements'.
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Affiliation(s)
- Grace E. Wardell
- Department of Animal Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 1EA, UK
| | - Michael F. Hynes
- Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta, Canada T2N 1N4
| | - Peter J. Young
- Department of Biology, University of York, Wentworth Way, York YO10 5DD, UK
| | - Ellie Harrison
- Department of Animal Plant Sciences, University of Sheffield, Western Bank, Sheffield S10 1EA, UK
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8
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Moeskjær S, Skovbjerg CK, Tausen M, Wind R, Roulund N, Janss L, Andersen SU. Major effect loci for plant size before onset of nitrogen fixation allow accurate prediction of yield in white clover. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2022; 135:125-143. [PMID: 34628514 DOI: 10.1007/s00122-021-03955-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 09/24/2021] [Indexed: 06/13/2023]
Abstract
Accurate genomic prediction of yield within and across generations was achieved by estimating the genetic merit of individual white clover genotypes based on extensive genetic replication using cloned material. White clover is an agriculturally important forage legume grown throughout temperate regions as a mixed clover-grass crop. It is typically cultivated with low nitrogen input, making yield dependent on nitrogen fixation by rhizobia in root nodules. Here, we investigate the effects of clover and rhizobium genetic variation by monitoring plant growth and quantifying dry matter yield of 704 combinations of 145 clover genotypes and 170 rhizobium inocula. We find no significant effect of rhizobium variation. In contrast, we can predict yield based on a few white clover markers strongly associated with plant size prior to nitrogen fixation, and the prediction accuracy for polycross offspring yield is remarkably high. Several of the markers are located near a homolog of Arabidopsis thaliana GIGANTUS 1, which regulates growth rate and biomass accumulation. Our work provides fundamental insight into the genetics of white clover yield and identifies specific candidate genes as breeding targets.
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Affiliation(s)
- Sara Moeskjær
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus C, Denmark
| | | | - Marni Tausen
- Bioinformatics Research Centre, Aarhus University, 8000, Aarhus C, Denmark
- Center for Quantitative Genetics and Genomics, Aarhus University, 8000, Aarhus C, Denmark
| | - Rune Wind
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus C, Denmark
| | | | - Luc Janss
- Center for Quantitative Genetics and Genomics, Aarhus University, 8000, Aarhus C, Denmark
| | - Stig U Andersen
- Department of Molecular Biology and Genetics, Aarhus University, 8000, Aarhus C, Denmark.
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9
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Ford S, Moeskjær S, Young P, Santamaría RI, Harrison E. Introducing a Novel, Broad Host Range Temperate Phage Family Infecting Rhizobium leguminosarum and Beyond. Front Microbiol 2021; 12:765271. [PMID: 34858375 PMCID: PMC8631192 DOI: 10.3389/fmicb.2021.765271] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 10/13/2021] [Indexed: 02/01/2023] Open
Abstract
Temperate phages play important roles in bacterial communities but have been largely overlooked, particularly in non-pathogenic bacteria. In rhizobia the presence of temperate phages has the potential to have significant ecological impacts but few examples have been described. Here we characterize a novel group of 5 Rhizobium leguminosarum prophages, capable of sustaining infections across a broad host range within their host genus. Genome comparisons identified further putative prophages infecting multiple Rhizobium species isolated globally, revealing a wider family of 10 temperate phages including one previously described lytic phage, RHEph01, which appears to have lost the ability to form lysogens. Phylogenetic discordance between prophage and host phylogenies suggests a history of active mobilization between Rhizobium lineages. Genome comparisons revealed conservation of gene content and order, with the notable exception of an approximately 5 kb region of hypervariability, containing almost exclusively hypothetical genes. Additionally, several horizontally acquired genes are present across the group, including a putative antirepressor present only in the RHEph01 genome, which may explain its apparent inability to form lysogens. In summary, both phenotypic and genomic comparisons between members of this group of phages reveals a clade of viruses with a long history of mobilization within and between Rhizobium species.
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Affiliation(s)
- Sam Ford
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Sara Moeskjær
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
| | - Peter Young
- Department of Biology, University of York, York, United Kingdom
| | - Rosa I Santamaría
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, México City, Mexico
| | - Ellie Harrison
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, United Kingdom
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10
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Boivin S, Mahé F, Debellé F, Pervent M, Tancelin M, Tauzin M, Wielbo J, Mazurier S, Young P, Lepetit M. Genetic Variation in Host-Specific Competitiveness of the Symbiont Rhizobium leguminosarum Symbiovar viciae. FRONTIERS IN PLANT SCIENCE 2021; 12:719987. [PMID: 34567032 PMCID: PMC8457355 DOI: 10.3389/fpls.2021.719987] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 07/29/2021] [Indexed: 05/25/2023]
Abstract
Legumes of the Fabeae tribe form nitrogen-fixing root nodules resulting from symbiotic interaction with the soil bacteria Rhizobium leguminosarum symbiovar viciae (Rlv). These bacteria are all potential symbionts of the Fabeae hosts but display variable partner choice when co-inoculated in mixture. Because partner choice and symbiotic nitrogen fixation mostly behave as genetically independent traits, the efficiency of symbiosis is often suboptimal when Fabeae legumes are exposed to natural Rlv populations present in soil. A core collection of 32 Rlv bacteria was constituted based on the genomic comparison of a collection of 121 genome sequences, representative of known worldwide diversity of Rlv. A variable part of the nodD gene sequence was used as a DNA barcode to discriminate and quantify each of the 32 bacteria in mixture. This core collection was co-inoculated on a panel of nine genetically diverse Pisum sativum, Vicia faba, and Lens culinaris genotypes. We estimated the relative Early Partner Choice (EPC) of the bacteria with the Fabeae hosts by DNA metabarcoding on the nodulated root systems. Comparative genomic analyses within the bacterial core collection identified molecular markers associated with host-dependent symbiotic partner choice. The results revealed emergent properties of rhizobial populations. They pave the way to identify genes related to important symbiotic traits operating at this level.
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Affiliation(s)
- Stéphane Boivin
- Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Frederic Mahé
- Biologie et Génétique des Interactions Plante-Parasite, CIRAD, INRAE, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Frédéric Debellé
- Laboratoire des Interactions Plantes-Microorganismes, INRAE, CNRS, University of Toulouse, Castanet-Tolosan, France
| | - Marjorie Pervent
- Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Mathilde Tancelin
- Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Marc Tauzin
- Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Montpellier SupAgro, University of Montpellier, Montpellier, France
| | - Jerzy Wielbo
- Department of Genetics and Microbiology, Maria Curie-Skłodowska University, Lublin, Poland
| | - Sylvie Mazurier
- Agroecology, AgroSup Dijon, INRAE, University Burgundy Franche-Comté, Dijon, France
| | - Peter Young
- Department of Biology, University of York, York, United Kingdom
| | - Marc Lepetit
- Laboratoire des Symbioses Tropicales et Méditerranéennes, INRAE, IRD, CIRAD, Montpellier SupAgro, University of Montpellier, Montpellier, France
- Institut Sophia Agrobiotech, INRAE, CNRS, Côte d’Azur University, Sophia-Antipolis, France
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11
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Cavassim MIA, Andersen SU, Bataillon T, Schierup MH. Recombination facilitates adaptive evolution in rhizobial soil bacteria. Mol Biol Evol 2021; 38:5480-5490. [PMID: 34410427 PMCID: PMC8662638 DOI: 10.1093/molbev/msab247] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Homologous recombination is expected to increase natural selection efficacy by decoupling the fate of beneficial and deleterious mutations and by readily creating new combinations of beneficial alleles. Here, we investigate how the proportion of amino acid substitutions fixed by adaptive evolution (α) depends on the recombination rate in bacteria. We analyze 3,086 core protein-coding sequences from 196 genomes belonging to five closely related species of the genus Rhizobium. These genes are found in all species and do not display any signs of introgression between species. We estimate α using the site frequency spectrum (SFS) and divergence data for all pairs of species. We evaluate the impact of recombination within each species by dividing genes into three equally sized recombination classes based on their average level of intragenic linkage disequilibrium. We find that α varies from 0.07 to 0.39 across species and is positively correlated with the level of recombination. This is both due to a higher estimated rate of adaptive evolution and a lower estimated rate of nonadaptive evolution, suggesting that recombination both increases the fixation probability of advantageous variants and decreases the probability of fixation of deleterious variants. Our results demonstrate that homologous recombination facilitates adaptive evolution measured by α in the core genome of prokaryote species in agreement with studies in eukaryotes.
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Affiliation(s)
- Maria Izabel A Cavassim
- Bioinformatics Research Centre, Aarhus University, Aarhus, 8000, Denmark.,Department of Molecular Biology and Genetics, Aarhus University, Aarhus, 8000, Denmark
| | - Stig U Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, 8000, Denmark
| | - Thomas Bataillon
- Bioinformatics Research Centre, Aarhus University, Aarhus, 8000, Denmark
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12
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Mendoza-Suárez M, Andersen SU, Poole PS, Sánchez-Cañizares C. Competition, Nodule Occupancy, and Persistence of Inoculant Strains: Key Factors in the Rhizobium-Legume Symbioses. FRONTIERS IN PLANT SCIENCE 2021; 12:690567. [PMID: 34489993 PMCID: PMC8416774 DOI: 10.3389/fpls.2021.690567] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 07/19/2021] [Indexed: 05/06/2023]
Abstract
Biological nitrogen fixation by Rhizobium-legume symbioses represents an environmentally friendly and inexpensive alternative to the use of chemical nitrogen fertilizers in legume crops. Rhizobial inoculants, applied frequently as biofertilizers, play an important role in sustainable agriculture. However, inoculants often fail to compete for nodule occupancy against native rhizobia with inferior nitrogen-fixing abilities, resulting in low yields. Strains with excellent performance under controlled conditions are typically selected as inoculants, but the rates of nodule occupancy compared to native strains are rarely investigated. Lack of persistence in the field after agricultural cycles, usually due to the transfer of symbiotic genes from the inoculant strain to naturalized populations, also limits the suitability of commercial inoculants. When rhizobial inoculants are based on native strains with a high nitrogen fixation ability, they often have superior performance in the field due to their genetic adaptations to the local environment. Therefore, knowledge from laboratory studies assessing competition and understanding how diverse strains of rhizobia behave, together with assays done under field conditions, may allow us to exploit the effectiveness of native populations selected as elite strains and to breed specific host cultivar-rhizobial strain combinations. Here, we review current knowledge at the molecular level on competition for nodulation and the advances in molecular tools for assessing competitiveness. We then describe ongoing approaches for inoculant development based on native strains and emphasize future perspectives and applications using a multidisciplinary approach to ensure optimal performance of both symbiotic partners.
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Affiliation(s)
| | - Stig U. Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Philip S. Poole
- Department of Plant Sciences, University of Oxford, Oxford, United Kingdom
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Fields B, Moffat EK, Harrison E, Andersen SU, Young JPW, Friman VP. Genetic variation is associated with differences in facilitative and competitive interactions in the Rhizobium leguminosarum species complex. Environ Microbiol 2021; 24:3463-3485. [PMID: 34398510 DOI: 10.1111/1462-2920.15720] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Revised: 07/08/2021] [Accepted: 08/10/2021] [Indexed: 12/01/2022]
Abstract
Competitive and facilitative interactions influence bacterial community composition, diversity and functioning. However, the role of genetic diversity for determining interactions between coexisting strains of the same, or closely related, species remains poorly understood. Here, we investigated the type (facilitative/inhibitory) and potential underlying mechanisms of pairwise interactions between 24 genetically diverse bacterial strains belonging to three genospecies (gsA,C,E) of the Rhizobium leguminosarum species complex. Interactions were determined indirectly, based on secreted compounds in cell-free supernatants, and directly, as growth inhibition in cocultures. We found supernatants mediated both facilitative and inhibitory interactions that varied greatly between strains and genospecies. Overall, gsE strains indirectly suppressed growth of gsA strains, while their own growth was facilitated by other genospecies' supernatants. Similar genospecies-level patterns were observed in direct competition, where gsA showed the highest susceptibility and gsE the highest inhibition capacity. At the genetic level, increased gsA susceptibility was associated with a non-random distribution of quorum sensing and secondary metabolite genes across genospecies. Together, our results suggest that genetic variation is associated with facilitative and competitive interactions, which could be important ecological mechanisms explaining R. leguminosarum diversity.
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Affiliation(s)
| | - Emma K Moffat
- Department of Biology, University of York, York, UK.,Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Ellie Harrison
- Department of Animal and Plant Sciences, University of Sheffield, Sheffield, UK
| | - Stig U Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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Gürkanlı CT. Genetic diversity of rhizobia associated with Pisum sativum L. in the Northern part of Turkey. Biologia (Bratisl) 2021. [DOI: 10.1007/s11756-021-00831-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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15
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Impact of a bacterial consortium on the soil bacterial community structure and maize (Zea mays L.) cultivation. Sci Rep 2021; 11:13092. [PMID: 34158574 PMCID: PMC8219701 DOI: 10.1038/s41598-021-92517-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 06/07/2021] [Indexed: 02/05/2023] Open
Abstract
Microorganisms are often applied as biofertilizer to crops to stimulate plant growth, increase yields and reduce inorganic N application. The survival and proliferation of these allochthonous microorganisms in soil is a necessary requisite for them to promote plant growth. We applied a sterilized or unsterilized not commercialized bacterial consortium mixed with cow manure leachate used by a farmer as biofertilizer to maize (Zea mays L.) in a greenhouse experiment, while maize development and the bacterial community structure was determined just before the biofertilizer was applied a first time (day 44), after three applications (day 89) and after six application at the end of the experiment (day 130). Application of sterilized or unsterilized biofertilizer with pH 4.3 and 864 mg NH4+-N kg-1 had no significant effect on maize growth. The application of the biofertilizer dominated by Lactobacillus (relative abundance 11.90%) or the sterilized biofertilizer changed the relative abundance of a limited number of bacterial groups, i.e. Delftia, Halomonas, Lactobacillus and Stenotrophomonas, without altering significantly the bacterial community structure. Cultivation of maize, however, affected significantly the bacterial community structure, which showed large significant variations over time in the cultivated and uncultivated soil. It was concluded that the bacteria applied as a biofertilizer had only a limited effect on the relative abundance of these groups in uncultivated or soil cultivated with maize.
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Fields B, Moffat EK, Friman VP, Harrison E. The impact of intra-specific diversity in the rhizobia-legume symbiosis. MICROBIOLOGY-SGM 2021; 167. [PMID: 33829985 PMCID: PMC8289218 DOI: 10.1099/mic.0.001051] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Rhizobia - nitrogen-fixing, root-nodulating bacteria - play a critical role in both plant ecosystems and sustainable agriculture. Rhizobia form intracellular infections within legumes roots where they produce plant accessible nitrogen from atmospheric nitrogen and thus reduce the reliance on industrial inputs. The rhizobia-legume symbiosis is often treated as a pairwise relationship between single genotypes, both in research and in the production of rhizobial inoculants. However in nature individual plants are infected by a high diversity of rhizobia symbionts. How this diversity affects productivity within the symbiosis is unclear. Here, we use a powerful statistical approach to assess the impact of diversity within the Rhizobium leguminosarum - clover symbiosis using a biodiversity-ecosystem function framework. Statistically, we found no significant impact of rhizobium diversity. However this relationship was weakly positive - rather than negative - indicating that there is no significant cost to increasing inoculant diversity. Productivity was influenced by the identity of the strains within an inoculant; strains with the highest individual performance showed a significant positive contribution within mixed inoculants. Overall, inoculant effectiveness was best predicted by the individual performance of the best inoculant member, and only weakly predicted by the worst performing member. Collectively, our data suggest that the Rhizobium leguminosarum - clover symbiosis displays a weak diversity-function relationship, but that inoculant performance can be improved through the inclusion of high performing strains. Given the wide environmental dependence of rhizobial inoculant quality, multi-strain inoculants could be highly successful as they increase the likelihood of including a strain well adapted to local conditions across different environments.
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Affiliation(s)
- Bryden Fields
- Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK
| | - Emma K Moffat
- Department of Animal Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
| | - Ville-Petri Friman
- Department of Biology, University of York, Wentworth Way, York, YO10 5DD, UK
| | - Ellie Harrison
- Department of Animal Plant Sciences, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
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Young JPW, Moeskjær S, Afonin A, Rahi P, Maluk M, James EK, Cavassim MIA, Rashid MHO, Aserse AA, Perry BJ, Wang ET, Velázquez E, Andronov EE, Tampakaki A, Flores Félix JD, Rivas González R, Youseif SH, Lepetit M, Boivin S, Jorrin B, Kenicer GJ, Peix Á, Hynes MF, Ramírez-Bahena MH, Gulati A, Tian CF. Defining the Rhizobium leguminosarum Species Complex. Genes (Basel) 2021; 12:111. [PMID: 33477547 PMCID: PMC7831135 DOI: 10.3390/genes12010111] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 01/08/2021] [Accepted: 01/13/2021] [Indexed: 01/21/2023] Open
Abstract
Bacteria currently included in Rhizobium leguminosarum are too diverse to be considered a single species, so we can refer to this as a species complex (the Rlc). We have found 429 publicly available genome sequences that fall within the Rlc and these show that the Rlc is a distinct entity, well separated from other species in the genus. Its sister taxon is R. anhuiense. We constructed a phylogeny based on concatenated sequences of 120 universal (core) genes, and calculated pairwise average nucleotide identity (ANI) between all genomes. From these analyses, we concluded that the Rlc includes 18 distinct genospecies, plus 7 unique strains that are not placed in these genospecies. Each genospecies is separated by a distinct gap in ANI values, usually at approximately 96% ANI, implying that it is a 'natural' unit. Five of the genospecies include the type strains of named species: R. laguerreae, R. sophorae, R. ruizarguesonis, "R. indicum" and R. leguminosarum itself. The 16S ribosomal RNA sequence is remarkably diverse within the Rlc, but does not distinguish the genospecies. Partial sequences of housekeeping genes, which have frequently been used to characterize isolate collections, can mostly be assigned unambiguously to a genospecies, but alleles within a genospecies do not always form a clade, so single genes are not a reliable guide to the true phylogeny of the strains. We conclude that access to a large number of genome sequences is a powerful tool for characterizing the diversity of bacteria, and that taxonomic conclusions should be based on all available genome sequences, not just those of type strains.
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Affiliation(s)
| | - Sara Moeskjær
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus, Denmark;
| | - Alexey Afonin
- Laboratory for Genetics of Plant-Microbe Interactions, ARRIAM, Pushkin, 196608 Saint-Petersburg, Russia;
| | - Praveen Rahi
- National Centre for Microbial Resource, National Centre for Cell Science, Pune 411007, India;
| | - Marta Maluk
- Ecological Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK; (M.M.); (E.K.J.)
| | - Euan K. James
- Ecological Sciences, The James Hutton Institute, Invergowrie, Dundee DD2 5DA, UK; (M.M.); (E.K.J.)
| | - Maria Izabel A. Cavassim
- Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA;
| | - M. Harun-or Rashid
- Biotechnology Division, Bangladesh Institute of Nuclear Agriculture (BINA), Mymensingh 2202, Bangladesh;
| | - Aregu Amsalu Aserse
- Ecosystems and Environment Research Programme, Faculty of Biological and Environmental Sciences, University of Helsinki, FI-00014 Helsinki, Finland;
| | - Benjamin J. Perry
- Department of Microbiology and Immunology, University of Otago, Dunedin 9016, New Zealand;
| | - En Tao Wang
- Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Ciudad De México 11340, Mexico;
| | - Encarna Velázquez
- Departamento de Microbiología y Genética, Universidad de Salamanca, Instituto Hispanoluso de Investigaciones Agrarias (CIALE), Unidad Asociada Grupo de Interacción planta-microorganismo (Universidad de Salamanca-IRNASA-CSIC), 37007 Salamanca, Spain; (E.V.); (R.R.G.)
| | - Evgeny E. Andronov
- Department of Microbial Monitoring, ARRIAM, Pushkin, 196608 Saint-Petersburg, Russia;
| | - Anastasia Tampakaki
- Department of Crop Science, Agricultural University of Athens, Iera Odos 75, Votanikos, 11855 Athens, Greece;
| | - José David Flores Félix
- CICS-UBI—Health Sciences Research Centre, University of Beira Interior, 6201-506 Covilhã, Portugal;
| | - Raúl Rivas González
- Departamento de Microbiología y Genética, Universidad de Salamanca, Instituto Hispanoluso de Investigaciones Agrarias (CIALE), Unidad Asociada Grupo de Interacción planta-microorganismo (Universidad de Salamanca-IRNASA-CSIC), 37007 Salamanca, Spain; (E.V.); (R.R.G.)
| | - Sameh H. Youseif
- Department of Microbial Genetic Resources, National Gene Bank (NGB), Agricultural Research Center (ARC), Giza 12619, Egypt;
| | - Marc Lepetit
- Institut Sophia Agrobiotech, UMR INRAE 1355, Université Côte d’Azur, CNRS, 06903 Sophia Antipolis, France;
| | - Stéphane Boivin
- Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR INRAE-IRD-CIRAD-UM2-SupAgro, Campus International de Baillarguet, TA-A82/J, CEDEX 05, 34398 Montpellier, France;
| | - Beatriz Jorrin
- Department of Plant Sciences, University of Oxford, Oxford OX1 3RB, UK;
| | - Gregory J. Kenicer
- Royal Botanic Garden Edinburgh, 20A Inverleith Row, Edinburgh EH3 5LR, UK;
| | - Álvaro Peix
- Instituto de Recursos Naturales y Agrobiología de Salamanca (IRNASA-CSIC), Unidad Asociada Grupo de Interacción Planta-Microorganismo (Universidad de Salamanca-IRNASA-CSIC), 37008 Salamanca, Spain;
| | - Michael F. Hynes
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada;
| | - Martha Helena Ramírez-Bahena
- Departamento de Didáctica de las Matemáticas y de las Ciencias Experimentales. Universidad de Salamanca, 37008 Salamanca, Spain;
| | - Arvind Gulati
- Microbial Prospection, CSIR-Institute of Himalayan Bioresource Technology, Palampur (H.P.) 176 061, India;
| | - Chang-Fu Tian
- State Key Laboratory of Agrobiotechnology, Rhizobium Research Center, and College of Biological Sciences, China Agricultural University, Beijing 100193, China;
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Epstein B, Tiffin P. Comparative genomics reveals high rates of horizontal transfer and strong purifying selection on rhizobial symbiosis genes. Proc Biol Sci 2021; 288:20201804. [PMID: 33402066 DOI: 10.1098/rspb.2020.1804] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Horizontal transfer (HT) alters the repertoire of symbiosis genes in rhizobial genomes and may play an important role in the on-going evolution of the rhizobia-legume symbiosis. To gain insight into the extent of HT of symbiosis genes with different functional roles (nodulation, N-fixation, host benefit and rhizobial fitness), we conducted comparative genomic and selection analyses of the full-genome sequences from 27 rhizobial genomes. We find that symbiosis genes experience high rates of HT among rhizobial lineages but also bear signatures of purifying selection (low Ka : Ks). HT and purifying selection appear to be particularly strong in genes involved in initiating the symbiosis (e.g. nodulation) and in genome-wide association candidates for mediating benefits provided to the host. These patterns are consistent with rhizobia adapting to the host environment through the loss and gain of symbiosis genes, but not with host-imposed positive selection driving divergence of symbiosis genes through recurring bouts of positive selection.
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Affiliation(s)
- Brendan Epstein
- Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, USA
| | - Peter Tiffin
- Department of Plant and Microbial Biology, University of Minnesota, St Paul, MN, USA
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Fields B, Moeskjaer S, Friman VP, Andersen SU, Young JPW. MAUI-seq: Metabarcoding using amplicons with unique molecular identifiers to improve error correction. Mol Ecol Resour 2020; 21:703-720. [PMID: 33171018 DOI: 10.1111/1755-0998.13294] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 10/22/2020] [Accepted: 11/05/2020] [Indexed: 12/18/2022]
Abstract
Sequencing and PCR errors are a major challenge when characterizing genetic diversity using high-throughput amplicon sequencing (HTAS). We have developed a multiplexed HTAS method, MAUI-seq, which uses unique molecular identifiers (UMIs) to improve error correction by exploiting variation among sequences associated with a single UMI. Erroneous sequences are recognized because, across the data set, they are over-represented among the minor sequences associated with UMIs. We show that two main advantages of this approach are efficient elimination of chimeric and other erroneous reads, outperforming dada2 and unoise3, and the ability to confidently recognize genuine alleles that are present at low abundance or resemble chimeras. The method provides sensitive and flexible profiling of diversity and is readily adaptable to most HTAS applications, including microbial 16S rRNA profiling and metabarcoding of environmental DNA.
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Affiliation(s)
| | - Sara Moeskjaer
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | | | - Stig U Andersen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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Youseif SH, Abd El-Megeed FH, Mohamed AH, Ageez A, Veliz E, Martínez-Romero E. Diverse Rhizobium strains isolated from root nodules of Trifolium alexandrinum in Egypt and symbiovars. Syst Appl Microbiol 2020; 44:126156. [PMID: 33232849 DOI: 10.1016/j.syapm.2020.126156] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 11/01/2020] [Accepted: 11/02/2020] [Indexed: 12/18/2022]
Abstract
Berseem clover (T. alexandrinum) is the main forage legume crop used as animal feed in Egypt. Here, eighty rhizobial isolates were isolated from root nodules of berseem clover grown in different regions in Egypt and were grouped by RFLP-16S rRNA ribotyping. Representative isolates were characterized using phylogenetic analyses of the 16S rRNA, rpoB, glnA, pgi, and nodC genes. We also investigated the performance of these isolates using phenotypic tests and nitrogen fixation efficiency assays. The majority of strains (<90%) were closely related to Rhizobium aegyptiacum and Rhizobium aethiopicum and of the remaining strains, six belonged to the Rhizobium leguminosarum genospecies complex and only one strain was assigned to Agrobacterium fabacearum. Despite their heterogeneous chromosomal background, most of the strains shared nodC gene alleles corresponding to symbiovar trifolii. Some of the strains closely affiliated to R. aegyptiacum and R. aethiopicum had superior nodulation and nitrogen fixation capabilities in berseem clover, compared to the commercial inoculant (Okadein®) and N-added treatments. R. leguminosarum strain NGB-CR 17 that harbored a nodC allele typical of symbiovar viciae, was also able to form an effective symbiosis with clover. Two strains with nodC alleles of symbiovar trifolii, R. aegyptiacum strains NGB-CR 129 and 136, were capable of forming effective nodules in Phaseolus vulgaris in axenic greenhouse conditions. This adds the symbiovar trifolii which is well-established in the Egyptian soils to the list of symbiovars that form nodules in P. vulgaris.
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Affiliation(s)
- Sameh H Youseif
- Department of Microbial Genetic Resources, National Gene Bank, Agricultural Research Center (ARC), Giza 12619, Egypt.
| | - Fayrouz H Abd El-Megeed
- Department of Microbial Genetic Resources, National Gene Bank, Agricultural Research Center (ARC), Giza 12619, Egypt
| | - Akram H Mohamed
- Department of Microbial Genetic Resources, National Gene Bank, Agricultural Research Center (ARC), Giza 12619, Egypt
| | - Amr Ageez
- Agricultural Genetic Engineering Research Institute, Agricultural Research Center (ARC), Giza 12619, Egypt; Faculty of Biotechnology, MSA University, 6 October City, Egypt
| | - Esteban Veliz
- Department of Plant Biology, University of California, Davis, Life Sciences Addition, 1 Shields Ave., Davis, CA, 95616, USA
| | - Esperanza Martínez-Romero
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, UNAM Cuernavaca, Morelos, Mexico
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21
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Tausen M, Clausen M, Moeskjær S, Shihavuddin ASM, Dahl AB, Janss L, Andersen SU. Greenotyper: Image-Based Plant Phenotyping Using Distributed Computing and Deep Learning. FRONTIERS IN PLANT SCIENCE 2020; 11:1181. [PMID: 32849731 PMCID: PMC7427585 DOI: 10.3389/fpls.2020.01181] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 07/21/2020] [Indexed: 05/07/2023]
Abstract
Image-based phenotype data with high temporal resolution offers advantages over end-point measurements in plant quantitative genetics experiments, because growth dynamics can be assessed and analysed for genotype-phenotype association. Recently, network-based camera systems have been deployed as customizable, low-cost phenotyping solutions. Here, we implemented a large, automated image-capture system based on distributed computing using 180 networked Raspberry Pi units that could simultaneously monitor 1,800 white clover (Trifolium repens) plants. The camera system proved stable with an average uptime of 96% across all 180 cameras. For analysis of the captured images, we developed the Greenotyper image analysis pipeline. It detected the location of the plants with a bounding box accuracy of 97.98%, and the U-net-based plant segmentation had an intersection over union accuracy of 0.84 and a pixel accuracy of 0.95. We used Greenotyper to analyze a total of 355,027 images, which required 24-36 h. Automated phenotyping using a large number of static cameras and plants thus proved a cost-effective alternative to systems relying on conveyor belts or mobile cameras.
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Affiliation(s)
- Marni Tausen
- Bioinformatics Research Centre, Aarhus University, Aarhus, Denmark
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Marc Clausen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - Sara Moeskjær
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
| | - ASM Shihavuddin
- Image Analysis & Computer Graphics, DTU Compute, Lyngby, Denmark
- EEE Department, Green University of Bangladesh (GUB), Dhaka, Bangladesh
| | | | - Luc Janss
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark
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