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Nitrogen-Fixing Symbiotic Paraburkholderia Species: Current Knowledge and Future Perspectives. NITROGEN 2023. [DOI: 10.3390/nitrogen4010010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/11/2023] Open
Abstract
A century after the discovery of rhizobia, the first Beta-proteobacteria species (beta-rhizobia) were isolated from legume nodules in South Africa and South America. Since then, numerous species belonging to the Burkholderiaceae family have been isolated. The presence of a highly branching lineage of nodulation genes in beta-rhizobia suggests a long symbiotic history. In this review, we focus on the beta-rhizobial genus Paraburkholderia, which includes two main groups: the South American mimosoid-nodulating Paraburkholderia and the South African predominantly papilionoid-nodulating Paraburkholderia. Here, we discuss the latest knowledge on Paraburkholderia nitrogen-fixing symbionts in each step of the symbiosis, from their survival in the soil, through the first contact with the legumes until the formation of an efficient nitrogen-fixing symbiosis in root nodules. Special attention is given to the strain P. phymatum STM815T that exhibits extraordinary features, such as the ability to: (i) enter into symbiosis with more than 50 legume species, including the agriculturally important common bean, (ii) outcompete other rhizobial species for nodulation of several legumes, and (iii) endure stressful soil conditions (e.g., high salt concentration and low pH) and high temperatures.
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Regulation of the Leucine Metabolism in Mortierella alpina. J Fungi (Basel) 2022; 8:jof8020196. [PMID: 35205950 PMCID: PMC8880518 DOI: 10.3390/jof8020196] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/14/2022] [Accepted: 02/15/2022] [Indexed: 12/20/2022] Open
Abstract
The oleaginous fungus Mortierella alpina is a safe source of polyunsaturated fatty acids (PUFA) in industrial food and feed production. Besides PUFA production, pharmaceutically relevant surface-active and antimicrobial oligopeptides were isolated from this basal fungus. Both production of fatty acids and oligopeptides rely on the biosynthesis and high turnover of branched-chain-amino acids (BCAA), especially l-leucine. However, the regulation of BCAA biosynthesis in basal fungi is largely unknown. Here, we report on the regulation of the leucine, isoleucine, and valine metabolism in M. alpina. In contrast to higher fungi, the biosynthetic genes for BCAA are hardly transcriptionally regulated, as shown by qRT-PCR analysis, which suggests a constant production of BCAAs. However, the enzymes of the leucine metabolism are tightly metabolically regulated. Three enzymes of the leucine metabolism were heterologously produced in Escherichia coli, one of which is inhibited by allosteric feedback loops: The key regulator is the α-isopropylmalate synthase LeuA1, which is strongly disabled by l-leucine, α-ketoisocaproate, and propionyl-CoA, the precursor of the odd-chain fatty acid catabolism. Its gene is not related to homologs from higher fungi, but it has been inherited from a phototrophic ancestor by horizontal gene transfer.
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Evolutionary origin and ecological implication of a unique nif island in free-living Bradyrhizobium lineages. THE ISME JOURNAL 2021; 15:3195-3206. [PMID: 33990706 PMCID: PMC8528876 DOI: 10.1038/s41396-021-01002-z] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2021] [Revised: 04/21/2021] [Accepted: 04/28/2021] [Indexed: 02/03/2023]
Abstract
The alphaproteobacterial genus Bradyrhizobium has been best known as N2-fixing members that nodulate legumes, supported by the nif and nod gene clusters. Recent environmental surveys show that Bradyrhizobium represents one of the most abundant free-living bacterial lineages in the world's soils. However, our understanding of Bradyrhizobium comes largely from symbiotic members, biasing the current knowledge of their ecology and evolution. Here, we report the genomes of 88 Bradyrhizobium strains derived from diverse soil samples, including both nif-carrying and non-nif-carrying free-living (nod free) members. Phylogenomic analyses of these and 252 publicly available Bradyrhizobium genomes indicate that nif-carrying free-living members independently evolved from symbiotic ancestors (carrying both nif and nod) multiple times. Intriguingly, the nif phylogeny shows that the vast majority of nif-carrying free-living members comprise an independent cluster, indicating that horizontal gene transfer promotes nif expansion among the free-living Bradyrhizobium. Comparative genomics analysis identifies that the nif genes found in free-living Bradyrhizobium are located on a unique genomic island of ~50 kb equipped with genes potentially involved in coping with oxygen tension. We further analyze amplicon sequencing data to show that Bradyrhizobium members presumably carrying this nif island are widespread in a variety of environments. Given the dominance of Bradyrhizobium in world's soils, our findings have implications for global nitrogen cycles and agricultural research.
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Nouwen N, Chaintreuil C, Fardoux J, Giraud E. A glutamate synthase mutant of Bradyrhizobium sp. strain ORS285 is unable to induce nodules on Nod factor-independent Aeschynomene species. Sci Rep 2021; 11:20910. [PMID: 34686745 PMCID: PMC8536739 DOI: 10.1038/s41598-021-00480-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/11/2021] [Indexed: 11/09/2022] Open
Abstract
The Bradyrhizobium sp. strain ORS285 is able to establish a nitrogen-fixing symbiosis with both Nod factor (NF) dependent and NF-independent Aeschynomene species. Here, we have studied the growth characteristics and symbiotic interaction of a glutamate synthase (GOGAT; gltD::Tn5) mutant of Bradyrhizobium ORS285. We show that the ORS285 gltD::Tn5 mutant is unable to use ammonium, nitrate and many amino acids as nitrogen source for growth and is unable to fix nitrogen under free-living conditions. Moreover, on several nitrogen sources, the growth rate of the gltB::Tn5 mutant was faster and/or the production of the carotenoid spirilloxanthin was much higher as compared to the wild-type strain. The absence of GOGAT activity has a drastic impact on the symbiotic interaction with NF-independent Aeschynomene species. With these species, inoculation with the ORS285 gltD::Tn5 mutant does not result in the formation of nodules. In contrast, the ORS285 gltD::Tn5 mutant is capable to induce nodules on NF-dependent Aeschynomene species, but these nodules were ineffective for nitrogen fixation. Interestingly, in NF-dependent and NF-independent Aeschynomene species inoculation with the ORS285 gltD::Tn5 mutant results in browning of the plant tissue at the site of the infection suggesting that the mutant bacteria induce plant defence responses.
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Affiliation(s)
- Nico Nouwen
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRAE/Université de Montpellier/CIRAD - Campus de Baillarguet, Montpellier, France.
| | - Clémence Chaintreuil
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRAE/Université de Montpellier/CIRAD - Campus de Baillarguet, Montpellier, France
| | - Joel Fardoux
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRAE/Université de Montpellier/CIRAD - Campus de Baillarguet, Montpellier, France
| | - Eric Giraud
- Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRAE/Université de Montpellier/CIRAD - Campus de Baillarguet, Montpellier, France
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5
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de Matos GF, Rouws LFM, Simões-Araújo JL, Baldani JI. Evolution and function of nitrogen fixation gene clusters in sugarcane associated Bradyrhizobium strains. Environ Microbiol 2021; 23:6148-6162. [PMID: 33928743 DOI: 10.1111/1462-2920.15533] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 04/13/2021] [Accepted: 04/13/2021] [Indexed: 12/01/2022]
Abstract
Bradyrhizobium spp. are well known to mediate biological nitrogen fixation (BNF) as microsymbionts inhabiting nodules on leguminous plants. However, they may also contribute to plant growth via free-living N2 fixation (FLNF) in association with non-legumes. Notably, several Bradyrhizobium strains from sugarcane roots display FLNF activity. Among them, Bradyrhizobium sacchari is a legume symbiotic species, whereas strains AG48 and M12 are non-symbiotic. In the present study, a phylogenomic approach was applied to study peculiarities of these and other Bradyrhizobium strains with respect to N fixation (nif) gene content in order to reveal genetic features that enable FNLF in Bradyrhizobium spp. All FLNF strains carry an ancestral 'non-symbiotic' nif-gene cluster (NSC). B. sacchari also contains a second 'symbiotic' nif-gene cluster (SC), a characteristic observed in only three of 156 evaluated genomes. B. sacchari stood out and presented a high level of sequence divergence between individual nif-gene homologues and we discuss scenarios for the evolutionary origin of these clusters. The transcript level of NSC nifH gene increased during FLNF, when compared to symbiotic conditions. The data suggest that sugarcane roots harbor diverse Bradyrhizobium spp. that are genetically adapted to a dynamic environment where leguminous and non-leguminous host plants are alternately available.
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Affiliation(s)
- Gustavo Feitosa de Matos
- Curso de Pós-graduação em Fitotecnia, Universidade Federal Rural do Rio de Janeiro, Rodovia BR 465 km 7, Seropédica, RJ, 23891-000, Brazil
| | | | | | - José Ivo Baldani
- Embrapa Agrobiologia, Rodovia BR 465 km 7, Seropédica, RJ, 23891-000, Brazil
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Bellés-Sancho P, Lardi M, Liu Y, Hug S, Pinto-Carbó MA, Zamboni N, Pessi G. Paraburkholderia phymatum Homocitrate Synthase NifV Plays a Key Role for Nitrogenase Activity during Symbiosis with Papilionoids and in Free-Living Growth Conditions. Cells 2021; 10:cells10040952. [PMID: 33924023 PMCID: PMC8073898 DOI: 10.3390/cells10040952] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 04/14/2021] [Accepted: 04/17/2021] [Indexed: 12/29/2022] Open
Abstract
Homocitrate is an essential component of the iron-molybdenum cofactor of nitrogenase, the bacterial enzyme that catalyzes the reduction of dinitrogen (N2) to ammonia. In nitrogen-fixing and nodulating alpha-rhizobia, homocitrate is usually provided to bacteroids in root nodules by their plant host. In contrast, non-nodulating free-living diazotrophs encode the homocitrate synthase (NifV) and reduce N2 in nitrogen-limiting free-living conditions. Paraburkholderia phymatum STM815 is a beta-rhizobial strain, which can enter symbiosis with a broad range of legumes, including papilionoids and mimosoids. In contrast to most alpha-rhizobia, which lack nifV, P. phymatum harbors a copy of nifV on its symbiotic plasmid. We show here that P. phymatum nifV is essential for nitrogenase activity both in root nodules of papilionoid plants and in free-living growth conditions. Notably, nifV was dispensable in nodules of Mimosa pudica despite the fact that the gene was highly expressed during symbiosis with all tested papilionoid and mimosoid plants. A metabolome analysis of papilionoid and mimosoid root nodules infected with the P. phymatum wild-type strain revealed that among the approximately 400 measured metabolites, homocitrate and other metabolites involved in lysine biosynthesis and degradation have accumulated in all plant nodules compared to uninfected roots, suggesting an important role of these metabolites during symbiosis.
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Affiliation(s)
- Paula Bellés-Sancho
- Department of Plant and Microbial Biology, University of Zürich, CH-8057 Zürich, Switzerland; (P.B.-S.); (M.L.); (Y.L.); (S.H.); (M.A.P.-C.)
| | - Martina Lardi
- Department of Plant and Microbial Biology, University of Zürich, CH-8057 Zürich, Switzerland; (P.B.-S.); (M.L.); (Y.L.); (S.H.); (M.A.P.-C.)
| | - Yilei Liu
- Department of Plant and Microbial Biology, University of Zürich, CH-8057 Zürich, Switzerland; (P.B.-S.); (M.L.); (Y.L.); (S.H.); (M.A.P.-C.)
| | - Sebastian Hug
- Department of Plant and Microbial Biology, University of Zürich, CH-8057 Zürich, Switzerland; (P.B.-S.); (M.L.); (Y.L.); (S.H.); (M.A.P.-C.)
| | - Marta Adriana Pinto-Carbó
- Department of Plant and Microbial Biology, University of Zürich, CH-8057 Zürich, Switzerland; (P.B.-S.); (M.L.); (Y.L.); (S.H.); (M.A.P.-C.)
| | - Nicola Zamboni
- ETH Zürich, Institute of Molecular Systems Biology, CH-8093 Zürich, Switzerland;
| | - Gabriella Pessi
- Department of Plant and Microbial Biology, University of Zürich, CH-8057 Zürich, Switzerland; (P.B.-S.); (M.L.); (Y.L.); (S.H.); (M.A.P.-C.)
- Correspondence: ; Tel.: +41-44-63-52904
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Leyva VE, Lopez JM, Zevallos-Ventura A, Cabrera R, Cañari-Chumpitaz C, Toubiana D, Maruenda H. NMR-based leaf metabolic profiling of V. planifolia and three endemic Vanilla species from the Peruvian Amazon. Food Chem 2021; 358:129365. [PMID: 33930711 DOI: 10.1016/j.foodchem.2021.129365] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 01/11/2021] [Accepted: 02/11/2021] [Indexed: 11/29/2022]
Abstract
The fruit of Vanilla planifolia is broadly preferred by the agroindustry and gourmet markets due to its refined flavor and aroma. Peruvian Vanilla has been proposed as a possible source for genetic improvement of existing Vanilla cultivars, but, little has been done to facilitate comprehensive studies of these and other Vanilla. Here, a nuclear magnetic resonance (NMR) metabolomic platform was developed to profile for the first time the leaves - organ known to accumulate vanillin putative precursors - of V. planifolia and those of Peruvian V. pompona, V. palmarum, and V. ribeiroi, with the aim to determine metabolic differences among them. Analysis of the NMR spectra allowed the identification of thirty-six metabolites, twenty-five of which were quantified. One-way ANOVA and post-hoc Tukey test revealed that these metabolites changed significantly among species, whilst multivariate-analyses allowed the identification of malic and homocitric acids, together with two vanillin precursors, as relevant metabolic markers for species differentiation.
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Affiliation(s)
- Vanessa E Leyva
- Pontificia Universidad Católica del Perú, Departamento de Ciencias - Química, CERMN, Av. Universitaria 1801, Lima 32, Peru
| | - Juan M Lopez
- Pontificia Universidad Católica del Perú, Departamento de Ciencias - Química, CERMN, Av. Universitaria 1801, Lima 32, Peru
| | - Alvaro Zevallos-Ventura
- Pontificia Universidad Católica del Perú, Departamento de Ciencias - Química, CERMN, Av. Universitaria 1801, Lima 32, Peru
| | - Rodrigo Cabrera
- Pontificia Universidad Católica del Perú, Departamento de Ciencias - Química, CERMN, Av. Universitaria 1801, Lima 32, Peru
| | - Cristhian Cañari-Chumpitaz
- Pontificia Universidad Católica del Perú, Departamento de Ciencias - Química, CERMN, Av. Universitaria 1801, Lima 32, Peru
| | - David Toubiana
- Pontificia Universidad Católica del Perú, Departamento de Ciencias - Química, CERMN, Av. Universitaria 1801, Lima 32, Peru
| | - Helena Maruenda
- Pontificia Universidad Católica del Perú, Departamento de Ciencias - Química, CERMN, Av. Universitaria 1801, Lima 32, Peru.
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Nouwen N, Arrighi JF, Gully D, Giraud E. RibBX of Bradyrhizobium ORS285 Plays an Important Role in Intracellular Persistence in Various Aeschynomene Host Plants. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2021; 34:88-99. [PMID: 33226302 DOI: 10.1094/mpmi-07-20-0209-r] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Bradyrhizobium ORS285 forms a nitrogen-fixating symbiosis with both Nod factor (NF)-dependent and NF-independent Aeschynomene spp. The Bradyrhizobium ORS285 ribBA gene encodes for a putative bifunctional enzyme with 3,4-dihydroxybutanone phosphate (3,4-DHBP) synthase and guanosine triphosphate (GTP) cyclohydrolase II activities, catalyzing the initial steps in the riboflavin biosynthesis pathway. In this study, we show that inactivating the ribBA gene does not cause riboflavin auxotrophy under free-living conditions and that, as shown for RibBAs from other bacteria, the GTP cyclohydrolase II domain has no enzymatic activity. For this reason, we have renamed the annotated ribBA as ribBX. Because we were unable to identify other ribBA or ribA and ribB homologs in the genome of Bradyrhizobium ORS285, we hypothesize that the ORS285 strain can use unconventional enzymes or an alternative pathway for the initial steps of riboflavin biosynthesis. Inactivating ribBX has a drastic impact on the interaction of Bradyrhizobium ORS285 with many of the tested Aeschynomene spp. In these Aeschynomene spp., the ORS285 ribBX mutant is able to infect the plant host cells but the intracellular infection is not maintained and the nodules senesce early. This phenotype can be complemented by reintroduction of the 3,4-DHBP synthase domain alone. Our results indicate that, in Bradyrhizobium ORS285, the RibBX protein is not essential for riboflavin biosynthesis under free-living conditions and we hypothesize that its activity is needed to sustain riboflavin biosynthesis under certain symbiotic conditions.[Formula: see text] Copyright © 2021 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.
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Affiliation(s)
- Nico Nouwen
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, SupAgro, INRAE, University of Montpellier, Montpellier, France
| | - Jean-Francois Arrighi
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, SupAgro, INRAE, University of Montpellier, Montpellier, France
| | - Djamel Gully
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, SupAgro, INRAE, University of Montpellier, Montpellier, France
| | - Eric Giraud
- Laboratoire des Symbioses Tropicales et Méditerranéennes, IRD, CIRAD, SupAgro, INRAE, University of Montpellier, Montpellier, France
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Liu A, Ku YS, Contador CA, Lam HM. The Impacts of Domestication and Agricultural Practices on Legume Nutrient Acquisition Through Symbiosis With Rhizobia and Arbuscular Mycorrhizal Fungi. Front Genet 2020; 11:583954. [PMID: 33193716 PMCID: PMC7554533 DOI: 10.3389/fgene.2020.583954] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 09/08/2020] [Indexed: 12/03/2022] Open
Abstract
Legumes are unique among plants as they can obtain nitrogen through symbiosis with nitrogen-fixing rhizobia that form root nodules in the host plants. Therefore they are valuable crops for sustainable agriculture. Increasing nitrogen fixation efficiency is not only important for achieving better plant growth and yield, but it is also crucial for reducing the use of nitrogen fertilizer. Arbuscular mycorrhizal fungi (AMF) are another group of important beneficial microorganisms that form symbiotic relationships with legumes. AMF can promote host plant growth by providing mineral nutrients and improving the soil ecosystem. The trilateral legume-rhizobia-AMF symbiotic relationships also enhance plant development and tolerance against biotic and abiotic stresses. It is known that domestication and agricultural activities have led to the reduced genetic diversity of cultivated germplasms and higher sensitivity to nutrient deficiencies in crop plants, but how domestication has impacted the capability of legumes to establish beneficial associations with rhizospheric microbes (including rhizobia and fungi) is not well-studied. In this review, we will discuss the impacts of domestication and agricultural practices on the interactions between legumes and soil microbes, focusing on the effects on AMF and rhizobial symbioses and hence nutrient acquisition by host legumes. In addition, we will summarize the genes involved in legume-microbe interactions and studies that have contributed to a better understanding of legume symbiotic associations using metabolic modeling.
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Affiliation(s)
| | | | | | - Hon-Ming Lam
- Centre for Soybean Research of the State Key Laboratory of Agrobiotechnology and School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
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Lindström K, Mousavi SA. Effectiveness of nitrogen fixation in rhizobia. Microb Biotechnol 2020; 13:1314-1335. [PMID: 31797528 PMCID: PMC7415380 DOI: 10.1111/1751-7915.13517] [Citation(s) in RCA: 124] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 11/13/2019] [Accepted: 11/13/2019] [Indexed: 12/01/2022] Open
Abstract
Biological nitrogen fixation in rhizobia occurs primarily in root or stem nodules and is induced by the bacteria present in legume plants. This symbiotic process has fascinated researchers for over a century, and the positive effects of legumes on soils and their food and feed value have been recognized for thousands of years. Symbiotic nitrogen fixation uses solar energy to reduce the inert N2 gas to ammonia at normal temperature and pressure, and is thus today, especially, important for sustainable food production. Increased productivity through improved effectiveness of the process is seen as a major research and development goal. The interaction between rhizobia and their legume hosts has thus been dissected at agronomic, plant physiological, microbiological and molecular levels to produce ample information about processes involved, but identification of major bottlenecks regarding efficiency of nitrogen fixation has proven to be complex. We review processes and results that contributed to the current understanding of this fascinating system, with focus on effectiveness of nitrogen fixation in rhizobia.
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Affiliation(s)
- Kristina Lindström
- Faculty of Biological and Environmental Sciences and Helsinki Institute of Sustainability Science (HELSUS)University of HelsinkiFI‐00014HelsinkiFinland
| | - Seyed Abdollah Mousavi
- Faculty of Biological and Environmental Sciences and Helsinki Institute of Sustainability Science (HELSUS)University of HelsinkiFI‐00014HelsinkiFinland
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11
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Younginger BS, Friesen ML. Connecting signals and benefits through partner choice in plant-microbe interactions. FEMS Microbiol Lett 2020; 366:5626345. [PMID: 31730203 DOI: 10.1093/femsle/fnz217] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 10/17/2019] [Indexed: 12/20/2022] Open
Abstract
Stabilizing mechanisms in plant-microbe symbioses are critical to maintaining beneficial functions, with two main classes: host sanctions and partner choice. Sanctions are currently presumed to be more effective and widespread, based on the idea that microbes rapidly evolve cheating while retaining signals matching cooperative strains. However, hosts that effectively discriminate among a pool of compatible symbionts would gain a significant fitness advantage. Using the well-characterized legume-rhizobium symbiosis as a model, we evaluate the evidence for partner choice in the context of the growing field of genomics. Empirical studies that rely upon bacteria varying only in nitrogen-fixation ability ignore host-symbiont signaling and frequently conclude that partner choice is not a robust stabilizing mechanism. Here, we argue that partner choice is an overlooked mechanism of mutualism stability and emphasize that plants need not use the microbial services provided a priori to discriminate among suitable partners. Additionally, we present a model that shows that partner choice signaling increases symbiont and host fitness in the absence of sanctions. Finally, we call for a renewed focus on elucidating the signaling mechanisms that are critical to partner choice while further aiming to understand their evolutionary dynamics in nature.
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Affiliation(s)
- Brett S Younginger
- Department of Plant Pathology, Washington State University, PO Box 646430, 345 Johnson Hall, Pullman, WA 99164, USA
| | - Maren L Friesen
- Department of Plant Pathology, Washington State University, PO Box 646430, 345 Johnson Hall, Pullman, WA 99164, USA.,Department of Crop and Soil Sciences, Washington State University, PO Box 646420, 115 Johnson Hall, Pullman, WA 99164, USA
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12
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Mergaert P, Kereszt A, Kondorosi E. Gene Expression in Nitrogen-Fixing Symbiotic Nodule Cells in Medicago truncatula and Other Nodulating Plants. THE PLANT CELL 2020; 32:42-68. [PMID: 31712407 PMCID: PMC6961632 DOI: 10.1105/tpc.19.00494] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Accepted: 11/08/2019] [Indexed: 05/06/2023]
Abstract
Root nodules formed by plants of the nitrogen-fixing clade (NFC) are symbiotic organs that function in the maintenance and metabolic integration of large populations of nitrogen-fixing bacteria. These organs feature unique characteristics and processes, including their tissue organization, the presence of specific infection structures called infection threads, endocytotic uptake of bacteria, symbiotic cells carrying thousands of intracellular bacteria without signs of immune responses, and the integration of symbiont and host metabolism. The early stages of nodulation are governed by a few well-defined functions, which together constitute the common symbiosis-signaling pathway (CSSP). The CSSP activates a set of transcription factors (TFs) that orchestrate nodule organogenesis and infection. The later stages of nodule development require the activation of hundreds to thousands of genes, mostly expressed in symbiotic cells. Many of these genes are only active in symbiotic cells, reflecting the unique nature of nodules as plant structures. Although how the nodule-specific transcriptome is activated and connected to early CSSP-signaling is poorly understood, candidate TFs have been identified using transcriptomic approaches, and the importance of epigenetic and chromatin-based regulation has been demonstrated. We discuss how gene regulation analyses have advanced our understanding of nodule organogenesis, the functioning of symbiotic cells, and the evolution of symbiosis in the NFC.
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Affiliation(s)
- Peter Mergaert
- Institute for Integrative Biology of the Cell, UMR 9198, CEA, CNRS, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Attila Kereszt
- Institute of Plant Biology, Biological Research Centre, 6726 Szeged, Hungary
| | - Eva Kondorosi
- Institute of Plant Biology, Biological Research Centre, 6726 Szeged, Hungary
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Hashimoto S, Wongdee J, Songwattana P, Greetatorn T, Goto K, Tittabutr P, Boonkerd N, Teaumroong N, Uchiumi T. Homocitrate Synthase Genes of Two Wide-Host-Range Bradyrhizobium Strains are Differently Required for Symbiosis Depending on Host Plants. Microbes Environ 2019; 34:393-401. [PMID: 31597890 PMCID: PMC6934396 DOI: 10.1264/jsme2.me19078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The nifV gene encodes homocitrate synthase, the enzyme that catalyzes the formation of homocitrate, which is essential for arranging the FeMo-cofactor in the catalytic center of nitrogenase. Some host plants, such as Lotus japonicus, supply homocitrate to their symbionts, in this case, Mesorhizobium loti, which lacks nifV. In contrast, Bradyrhizobium ORS285, a symbiont of Aeschynomene cross-inoculation (CI) groups 2 and 3, requires nifV for symbiosis with Aeschynomene species that belong to CI group 3, and some species belonging to CI group 2. However, it currently remains unclear whether rhizobial nifV is required for symbiosis with Aeschynomene species belonging to CI group 1 or with other legumes. We generated nifV-disruption (ΔnifV) mutants of two wide-host-range rhizobia, Bradyrhizobium SUTN9-2 and DOA9, to investigate whether they require nifV for symbiosis. Both ΔnifV mutant strains showed significantly less nitrogenase activity in a free-living state than the respective wild-type strains. The symbiotic phenotypes of SUTN9-2, DOA9, and their ΔnifV mutants were examined with four legumes, Aeschynomene americana, Stylosanthes hamata, Indigofera tinctoria, and Desmodium tortuosum. nifV was required for the efficient symbiosis of SUTN9-2 with A. americana (CI group 1), but not for that of DOA9. SUTN9-2 established symbiosis with all three other legumes; nifV was required for symbiosis with I. tinctoria and D. tortuosum. These results suggest that, in addition to Aeschynomene CI groups 2 and 3, CI group 1 and several other legumes require the rhizobial nifV for symbiosis.
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Affiliation(s)
- Shun Hashimoto
- Graduate School of Science and Engineering, Kagoshima University
| | - Jenjira Wongdee
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology
| | - Pongpan Songwattana
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology
| | - Teerana Greetatorn
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology
| | - Kohki Goto
- Graduate School of Science and Engineering, Kagoshima University
| | - Panlada Tittabutr
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology
| | - Nantakorn Boonkerd
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology
| | - Neung Teaumroong
- School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology
| | - Toshiki Uchiumi
- Graduate School of Science and Engineering, Kagoshima University
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14
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Saad MM, Michalet S, Fossou R, Putnik-Delić M, Crèvecoeur M, Meyer J, de Malézieux C, Hopfgartner G, Maksimović I, Perret X. Loss of NifQ Leads to Accumulation of Porphyrins and Altered Metal-Homeostasis in Nitrogen-Fixing Symbioses. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2019; 32:208-216. [PMID: 30070615 DOI: 10.1094/mpmi-07-18-0188-r] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Symbiotic nitrogen fixation between legumes and rhizobia involves a coordinated expression of many plant and bacterial genes as well as finely tuned metabolic activities of micro- and macrosymbionts. In spite of such complex interactions, symbiotic proficiency remains a resilient process, with host plants apparently capable of compensating for some deficiencies in rhizobia. What controls nodule homeostasis is still poorly understood and probably varies between plant species. In this respect, the promiscuous Sinorhizobium (Ensifer) fredii strain NGR234 has become a model to assess the relative contribution of single gene products to many symbioses. Here, we describe how a deletion in nifQ of NGR234 (strain NGRΔnifQ) makes nodules of Vigna unguiculata, V. radiata, and Macroptilium atropurpureum but not of the mimisoid tree Leucaena leucocephala, purple-red. This peculiar dark-nodule phenotype did not necessarily correlate with a decreased proficiency of NGRΔnifQ but coincided with a 20-fold or more accumulation of coproporphyrin III and uroporphyrin III in V. unguiculata nodules. Porphyrin accumulation was not restricted to plant cells infected with bacteroids but also extended to the nodule cortex. Nodule metal-homeostasis was altered but not sufficiently to prevent assembly and functioning of nitrogenase. Although the role of NifQ in donating molybdenum during assembly of nitrogenase cofactor FeMo-co makes it essential in free-living diazotrophs, our results highlight the dispensability of NifQ in many legume species.
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Affiliation(s)
- Maged M Saad
- 1 University of Geneva, Sciences III, Department of Botany and Plant Biology, Microbiology Unit, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
- 2 King Abdullah University of Science and Technology (KAUST), Biological and Environmental Sciences and Engineering Division (BESE), Thuwal 6900-2355, Kingdom of Saudi Arabia
| | - Sophie Michalet
- 3 University of Geneva, Mass Spectrometry Core Facility (MZ 2.0), Faculty of Sciences, Bd d'Yvoy 11, CH-1211 Geneva 4, Switzerland
| | - Romain Fossou
- 1 University of Geneva, Sciences III, Department of Botany and Plant Biology, Microbiology Unit, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | | | - Michèle Crèvecoeur
- 1 University of Geneva, Sciences III, Department of Botany and Plant Biology, Microbiology Unit, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Julien Meyer
- 3 University of Geneva, Mass Spectrometry Core Facility (MZ 2.0), Faculty of Sciences, Bd d'Yvoy 11, CH-1211 Geneva 4, Switzerland
| | - Chloé de Malézieux
- 1 University of Geneva, Sciences III, Department of Botany and Plant Biology, Microbiology Unit, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Gérard Hopfgartner
- 5 University of Geneva, Department of Inorganic and Analytical Chemistry, Faculty of Sciences, 26 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
| | - Ivana Maksimović
- 4 University of Novi Sad, Faculty of Agriculture, Novi Sad, Serbia; and
| | - Xavier Perret
- 1 University of Geneva, Sciences III, Department of Botany and Plant Biology, Microbiology Unit, 30 quai Ernest-Ansermet, CH-1211 Geneva 4, Switzerland
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15
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Brottier L, Chaintreuil C, Simion P, Scornavacca C, Rivallan R, Mournet P, Moulin L, Lewis GP, Fardoux J, Brown SC, Gomez-Pacheco M, Bourges M, Hervouet C, Gueye M, Duponnois R, Ramanankierana H, Randriambanona H, Vandrot H, Zabaleta M, DasGupta M, D’Hont A, Giraud E, Arrighi JF. A phylogenetic framework of the legume genus Aeschynomene for comparative genetic analysis of the Nod-dependent and Nod-independent symbioses. BMC PLANT BIOLOGY 2018; 18:333. [PMID: 30518342 PMCID: PMC6282307 DOI: 10.1186/s12870-018-1567-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Accepted: 11/23/2018] [Indexed: 05/04/2023]
Abstract
BACKGROUND Among semi-aquatic species of the legume genus Aeschynomene, some have the property of being nodulated by photosynthetic Bradyrhizobium lacking the nodABC genes necessary for the synthesis of Nod factors. Knowledge of the specificities underlying this Nod-independent symbiosis has been gained from the model legume Aeschynomene evenia but our understanding remains limited due to the lack of comparative genetics with related taxa using a Nod factor-dependent process. To fill this gap, we combined different approaches to perform a thorough comparative analysis in the genus Aeschynomene. RESULTS This study significantly broadened previous taxon sampling, including in allied genera, in order to construct a comprehensive phylogeny. In the phylogenetic tree, five main lineages were delineated, including a novel lineage, the Nod-independent clade and another one containing a polytomy that comprised several Aeschynomene groups and all the allied genera. This phylogeny was matched with data on chromosome number, genome size and low-copy nuclear gene sequences to reveal the diploid species and a polytomy containing mostly polyploid taxa. For these taxa, a single allopolyploid origin was inferred and the putative parental lineages were identified. Finally, nodulation tests with different Bradyrhizobium strains revealed new nodulation behaviours and the diploid species outside of the Nod-independent clade were compared for their experimental tractability and genetic diversity. CONCLUSIONS The extended knowledge of the genetics and biology of the different lineages sheds new light of the evolutionary history of the genus Aeschynomene and they provide a solid framework to exploit efficiently the diversity encountered in Aeschynomene legumes. Notably, our backbone tree contains all the species that are diploid and it clarifies the genetic relationships between the Nod-independent clade and the Nod-dependent lineages. This study enabled the identification of A. americana and A. patula as the most suitable species to undertake a comparative genetic study of the Nod-independent and Nod-dependent symbioses.
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Affiliation(s)
- Laurent Brottier
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, 34398 Montpellier, France
| | - Clémence Chaintreuil
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, 34398 Montpellier, France
| | - Paul Simion
- Institut des Sciences de l’Evolution (ISE-M), Université de Montpellier, CNRS, IRD, EPHE, 34095 Cedex 5 Montpellier, France
| | - Céline Scornavacca
- Institut des Sciences de l’Evolution (ISE-M), Université de Montpellier, CNRS, IRD, EPHE, 34095 Cedex 5 Montpellier, France
| | - Ronan Rivallan
- CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement), UMR AGAP, F-34398 Montpellier, France
- AGAP,Univ Montpellier, CIRAD, INRA, Montpellier SupAgro, 34060 Montpellier, France
| | - Pierre Mournet
- CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement), UMR AGAP, F-34398 Montpellier, France
- AGAP,Univ Montpellier, CIRAD, INRA, Montpellier SupAgro, 34060 Montpellier, France
| | - Lionel Moulin
- IRD, Interactions Plantes Microorganismes Environnement, UMR IPME, 34394 Montpellier, France
| | - Gwilym P. Lewis
- Comparative Plant and Fungal Biology Department, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB UK
| | - Joël Fardoux
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, 34398 Montpellier, France
| | - Spencer C. Brown
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Mario Gomez-Pacheco
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Mickaël Bourges
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud, Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Catherine Hervouet
- CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement), UMR AGAP, F-34398 Montpellier, France
- AGAP,Univ Montpellier, CIRAD, INRA, Montpellier SupAgro, 34060 Montpellier, France
| | - Mathieu Gueye
- Laboratoire de Botanique, Institut Fondamental d’Afrique Noire, Ch. A. Diop, BP 206 Dakar, Sénégal
| | - Robin Duponnois
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, 34398 Montpellier, France
| | - Heriniaina Ramanankierana
- Laboratoire de Microbiologie de l’Environnement/Centre National de Recherche sur l’Environnement, 101 Antananarivo, Madagascar
| | - Herizo Randriambanona
- Laboratoire de Microbiologie de l’Environnement/Centre National de Recherche sur l’Environnement, 101 Antananarivo, Madagascar
| | - Hervé Vandrot
- IAC, Laboratoire de Botanique et d’Ecologie Végétale Appliquée, UMR AMAP, 98825 Pouembout, Nouvelle-Calédonie France
| | - Maria Zabaleta
- Department of Biochemistry and Microbial Genomics, IIBCE, 11600 Montevideo, Uruguay
| | - Maitrayee DasGupta
- Department of Biochemistry, University of Calcutta, Kolkata, 700019 India
| | - Angélique D’Hont
- CIRAD (Centre de Coopération Internationale en Recherche Agronomique pour le Développement), UMR AGAP, F-34398 Montpellier, France
- AGAP,Univ Montpellier, CIRAD, INRA, Montpellier SupAgro, 34060 Montpellier, France
| | - Eric Giraud
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, 34398 Montpellier, France
| | - Jean-François Arrighi
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, 34398 Montpellier, France
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16
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Lamouche F, Gully D, Chaumeret A, Nouwen N, Verly C, Pierre O, Sciallano C, Fardoux J, Jeudy C, Szücs A, Mondy S, Salon C, Nagy I, Kereszt A, Dessaux Y, Giraud E, Mergaert P, Alunni B. Transcriptomic dissection of Bradyrhizobium sp. strain ORS285 in symbiosis with Aeschynomene spp. inducing different bacteroid morphotypes with contrasted symbiotic efficiency. Environ Microbiol 2018; 21:3244-3258. [PMID: 29921018 DOI: 10.1111/1462-2920.14292] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 05/18/2017] [Accepted: 05/19/2017] [Indexed: 11/29/2022]
Abstract
To circumvent the paucity of nitrogen sources in the soil legume plants establish a symbiotic interaction with nitrogen-fixing soil bacteria called rhizobia. During symbiosis, the plants form root organs called nodules, where bacteria are housed intracellularly and become active nitrogen fixers known as bacteroids. Depending on their host plant, bacteroids can adopt different morphotypes, being either unmodified (U), elongated (E) or spherical (S). E- and S-type bacteroids undergo a terminal differentiation leading to irreversible morphological changes and DNA endoreduplication. Previous studies suggest that differentiated bacteroids display an increased symbiotic efficiency (E > U and S > U). In this study, we used a combination of Aeschynomene species inducing E- or S-type bacteroids in symbiosis with Bradyrhizobium sp. ORS285 to show that S-type bacteroids present a better symbiotic efficiency than E-type bacteroids. We performed a transcriptomic analysis on E- and S-type bacteroids formed by Aeschynomene afraspera and Aeschynomene indica nodules and identified the bacterial functions activated in bacteroids and specific to each bacteroid type. Extending the expression analysis in E- and S-type bacteroids in other Aeschynomene species by qRT-PCR on selected genes from the transcriptome analysis narrowed down the set of bacteroid morphotype-specific genes. Functional analysis of a selected subset of 31 bacteroid-induced or morphotype-specific genes revealed no symbiotic phenotypes in the mutants. This highlights the robustness of the symbiotic program but could also indicate that the bacterial response to the plant environment is partially anticipatory or even maladaptive. Our analysis confirms the correlation between differentiation and efficiency of the bacteroids and provides a framework for the identification of bacterial functions that affect the efficiency of bacteroids.© 2018 Society for Applied Microbiology and John Wiley & Sons Ltd.
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Affiliation(s)
- Florian Lamouche
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Djamel Gully
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut pour la Recherche et le Développement, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, Montpellier, 34398, France
| | - Anaïs Chaumeret
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Nico Nouwen
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut pour la Recherche et le Développement, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, Montpellier, 34398, France
| | - Camille Verly
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Olivier Pierre
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Coline Sciallano
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut pour la Recherche et le Développement, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, Montpellier, 34398, France
| | - Joël Fardoux
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut pour la Recherche et le Développement, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, Montpellier, 34398, France
| | - Christian Jeudy
- Agroécologie, AgroSup Dijon, INRA, Université Bourgogne Franche-Comté, Dijon, 21065, France
| | - Attila Szücs
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary
| | - Samuel Mondy
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Christophe Salon
- Agroécologie, AgroSup Dijon, INRA, Université Bourgogne Franche-Comté, Dijon, 21065, France
| | - István Nagy
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary
- Seqomics Biotechnology Ltd, Mórahalom, 6782, Hungary
| | - Attila Kereszt
- Biological Research Centre, Hungarian Academy of Sciences, Szeged, 6726, Hungary
- Seqomics Biotechnology Ltd, Mórahalom, 6782, Hungary
| | - Yves Dessaux
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Eric Giraud
- Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut pour la Recherche et le Développement, UMR IRD/SupAgro/INRA/UM2/CIRAD, Campus International de Baillarguet, TA A-82/J, Montpellier, 34398, France
| | - Peter Mergaert
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
| | - Benoit Alunni
- Institute for Integrative Biology of the Cell, UMR 9198, CNRS/Université Paris-Sud/CEA, 91198, Gif-sur-Yvette, France
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17
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Challenges in Using Precision Agriculture to Optimize Symbiotic Nitrogen Fixation in Legumes: Progress, Limitations, and Future Improvements Needed in Diagnostic Testing. AGRONOMY-BASEL 2018. [DOI: 10.3390/agronomy8050078] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
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18
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Chaintreuil C, Perrier X, Martin G, Fardoux J, Lewis GP, Brottier L, Rivallan R, Gomez-Pacheco M, Bourges M, Lamy L, Thibaud B, Ramanankierana H, Randriambanona H, Vandrot H, Mournet P, Giraud E, Arrighi JF. Naturally occurring variations in the nod-independent model legume Aeschynomene evenia and relatives: a resource for nodulation genetics. BMC PLANT BIOLOGY 2018; 18:54. [PMID: 29614957 PMCID: PMC5883870 DOI: 10.1186/s12870-018-1260-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 03/06/2018] [Indexed: 05/21/2023]
Abstract
BACKGROUND Among semi-aquatic species of the legume genus Aeschynomene, some have the unique property of being root and stem-nodulated by photosynthetic Bradyrhizobium lacking the nodABC genes necessary for the production of Nod factors. These species provide an excellent biological system with which to explore the evolution of nodulation in legumes. Among them, Aeschynomene evenia has emerged as a model legume to undertake the genetic dissection of the so-called Nod-independent symbiosis. In addition to the genetic analysis of nodulation on a reference line, natural variation in a germplasm collection could also be surveyed to uncover genetic determinants of nodulation. To this aim, we investigated the patterns of genetic diversity in a collection of 226 Nod-independent Aeschynomene accessions. RESULTS A combination of phylogenetic analyses, comprising ITS and low-copy nuclear genes, along with cytogenetic experiments and artificial hybridizations revealed the richness of the Nod-independent Aeschynomene group with the identification of 13 diploid and 6 polyploid well-differentiated taxa. A set of 54 SSRs was used to further delineate taxon boundaries and to identify different genotypes. Patterns of microsatellite diversity also illuminated the genetic basis of the Aeschynomene taxa that were all found to be predominantly autogamous and with a predicted simple disomic inheritance, two attributes favorable for genetics. In addition, taxa displaying a pronounced genetic diversity, notably A. evenia, A. indica and A. sensitiva, were characterized by a clear geographically-based genetic structure and variations in root and stem nodulation. CONCLUSION A well-characterized germplasm collection now exists as a major genetic resource to thoroughly explore the natural variation of nodulation in response to different bradyrhizobial strains. Symbiotic polymorphisms are expected to be found notably in the induction of nodulation, in nitrogen fixation and also in stem nodulation. Subsequent genetic analysis and locus mapping will pave the way for the identification of the underlying genes through forward or reverse genetics. Such discoveries will significantly contribute to our understanding of the molecular mechanisms underpinning how some Aeschynomene species can be efficiently nodulated in a Nod-independent fashion.
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Affiliation(s)
- Clémence Chaintreuil
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| | - Xavier Perrier
- CIRAD, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, UMR AGAP, Campus de Lavalette, F-34398 Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Guillaume Martin
- CIRAD, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, UMR AGAP, Campus de Lavalette, F-34398 Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Joël Fardoux
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| | - Gwilym P. Lewis
- Comparative Plant and Fungal Biology Department, Royal Botanic Gardens, Kew, Richmond, Surrey, TW9 3AB UK
| | - Laurent Brottier
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| | - Ronan Rivallan
- CIRAD, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, UMR AGAP, Campus de Lavalette, F-34398 Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Mario Gomez-Pacheco
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud. Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Mickaël Bourges
- Institute of Integrative Biology of the Cell (I2BC), CEA, CNRS, Univ. Paris-Sud. Université Paris-Saclay, 91198 Gif-sur-Yvette, France
| | - Léo Lamy
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| | - Béatrice Thibaud
- CIRAD, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, UMR AGAP, Campus de Lavalette, F-34398 Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Heriniaina Ramanankierana
- Laboratoire de Microbiologie de l’Environnement/Centre National de Recherche sur l’Environnement, 101 Antananarivo, Madagascar
| | - Herizo Randriambanona
- Laboratoire de Microbiologie de l’Environnement/Centre National de Recherche sur l’Environnement, 101 Antananarivo, Madagascar
| | - Hervé Vandrot
- IAC, Laboratoire de Botanique et d’Ecologie Végétale Appliquée, UMR AMAP, 98825 Pouembout, Nouvelle-Calédonie, France
| | - Pierre Mournet
- CIRAD, Amélioration Génétique et Adaptation des Plantes Méditerranéennes et Tropicales, UMR AGAP, Campus de Lavalette, F-34398 Montpellier, France
- AGAP, Univ. Montpellier, CIRAD, INRA, Montpellier SupAgro, Montpellier, France
| | - Eric Giraud
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
| | - Jean-François Arrighi
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes, UMR LSTM, Campus International de Baillarguet, F-34398 Montpellier, France
- LSTM, Univ. Montpellier, CIRAD, INRA, IRD, Montpellier SupAgro, Montpellier, France
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