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Bouchiba Y, Esque J, Cottret L, Maréchaux M, Gaston M, Gasciolli V, Keller J, Nouwen N, Gully D, Arrighi J, Gough C, Lefebvre B, Barbe S, Bono J. An integrated approach reveals how lipo‐chitooligosaccharides interact with the lysin motif receptor‐like kinase
MtLYR3. Protein Sci 2022; 31:e4327. [PMID: 35634776 PMCID: PMC9115844 DOI: 10.1002/pro.4327] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/19/2022] [Accepted: 04/20/2022] [Indexed: 11/22/2022]
Abstract
N‐acetylglucosamine containing compounds acting as pathogenic or symbiotic signals are perceived by plant‐specific Lysin Motif Receptor‐Like Kinases (LysM‐RLKs). The molecular mechanisms of this perception are not fully understood, notably those of lipo‐chitooligosaccharides (LCOs) produced during root endosymbioses with nitrogen‐fixing bacteria or arbuscular mycorrhizal fungi. In Medicago truncatula, we previously identified the LysM‐RLK LYR3 (MtLYR3) as a specific LCO‐binding protein. We also showed that the absence of LCO binding to LYR3 of the non‐mycorrhizal Lupinus angustifolius, (LanLYR3), was related to LysM3, which differs from that of MtLYR3 by several amino acids and, particularly, by a critical tyrosine residue absent in LanLYR3. Here, we aimed to define the LCO binding site of MtLYR3 by using molecular modelling and simulation approaches, combined with site‐directed mutagenesis and LCO binding experiments. 3D models of MtLYR3 and LanLYR3 ectodomains were built, and homology modelling and molecular dynamics (MD) simulations were performed. Molecular docking and MD simulation on the LysM3 identified potential key residues for LCO binding. We highlighted by steered MD simulations that in addition to the critical tyrosine, two other residues were important for LCO binding in MtLYR3. Substitution of these residues in LanLYR3‐LysM3 by those of MtLYR3‐LysM3 allowed the recovery of high‐affinity LCO binding in experimental radioligand‐binding assays. An analysis of selective constraints revealed that the critical tyrosine has experienced positive selection pressure and is absent in some LYR3 proteins. These findings now pave the way to uncover the functional significance of this specific evolutionary pattern.
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Affiliation(s)
- Younes Bouchiba
- TBI, Université de Toulouse CNRS, INRAE, INSA Toulouse France
| | - Jérémy Esque
- TBI, Université de Toulouse CNRS, INRAE, INSA Toulouse France
| | - Ludovic Cottret
- LIPME, Université de Toulouse INRAE, CNRS Castanet‐Tolosan France
| | - Maude Maréchaux
- LIPME, Université de Toulouse INRAE, CNRS Castanet‐Tolosan France
| | - Mégane Gaston
- LIPME, Université de Toulouse INRAE, CNRS Castanet‐Tolosan France
| | | | - Jean Keller
- Laboratoire de Recherche en Sciences Végétales Université de Toulouse, CNRS, UPS Castanet‐Tolosan France
| | - Nico Nouwen
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) UMR IRD/SupAgro/INRAE/UM/CIRAD Montpellier France
| | - Djamel Gully
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) UMR IRD/SupAgro/INRAE/UM/CIRAD Montpellier France
| | - Jean‐François Arrighi
- IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM) UMR IRD/SupAgro/INRAE/UM/CIRAD Montpellier France
| | - Clare Gough
- LIPME, Université de Toulouse INRAE, CNRS Castanet‐Tolosan France
| | - Benoit Lefebvre
- LIPME, Université de Toulouse INRAE, CNRS Castanet‐Tolosan France
| | - Sophie Barbe
- TBI, Université de Toulouse CNRS, INRAE, INSA Toulouse France
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2
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Girardin A, Wang T, Ding Y, Keller J, Buendia L, Gaston M, Ribeyre C, Gasciolli V, Auriac MC, Vernié T, Bendahmane A, Ried MK, Parniske M, Morel P, Vandenbussche M, Schorderet M, Reinhardt D, Delaux PM, Bono JJ, Lefebvre B. LCO Receptors Involved in Arbuscular Mycorrhiza Are Functional for Rhizobia Perception in Legumes. Curr Biol 2019; 29:4249-4259.e5. [PMID: 31813608 PMCID: PMC6926482 DOI: 10.1016/j.cub.2019.11.038] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 08/09/2019] [Accepted: 11/12/2019] [Indexed: 01/10/2023]
Abstract
Bacterial lipo-chitooligosaccharides (LCOs) are key mediators of the nitrogen-fixing root nodule symbiosis (RNS) in legumes. The isolation of LCOs from arbuscular mycorrhizal fungi suggested that LCOs are also signaling molecules in arbuscular mycorrhiza (AM). However, the corresponding plant receptors have remained uncharacterized. Here we show that petunia and tomato mutants in the LysM receptor-like kinases LYK10 are impaired in AM formation. Petunia and tomato LYK10 proteins have a high affinity for LCOs (Kd in the nM range) comparable to that previously reported for a legume LCO receptor essential for the RNS. Interestingly, the tomato and petunia LYK10 promoters, when introduced into a legume, were active in nodules similarly to the promoter of the legume orthologous gene. Moreover, tomato and petunia LYK10 coding sequences restored nodulation in legumes mutated in their orthologs. This combination of genetic and biochemical data clearly pinpoints Solanaceous LYK10 as part of an ancestral LCO perception system involved in AM establishment, which has been directly recruited during evolution of the RNS in legumes.
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Affiliation(s)
- Ariane Girardin
- LIPM, Université de Toulouse, INRA, CNRS, 31326 Castanet-Tolosan, France
| | - Tongming Wang
- LIPM, Université de Toulouse, INRA, CNRS, 31326 Castanet-Tolosan, France
| | - Yi Ding
- LIPM, Université de Toulouse, INRA, CNRS, 31326 Castanet-Tolosan, France
| | - Jean Keller
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, Auzeville, BP42617, 31326 Castanet-Tolosan, France
| | - Luis Buendia
- LIPM, Université de Toulouse, INRA, CNRS, 31326 Castanet-Tolosan, France
| | - Mégane Gaston
- LIPM, Université de Toulouse, INRA, CNRS, 31326 Castanet-Tolosan, France
| | - Camille Ribeyre
- LIPM, Université de Toulouse, INRA, CNRS, 31326 Castanet-Tolosan, France
| | - Virginie Gasciolli
- LIPM, Université de Toulouse, INRA, CNRS, 31326 Castanet-Tolosan, France
| | - Marie-Christine Auriac
- LIPM, Université de Toulouse, INRA, CNRS, 31326 Castanet-Tolosan, France; Institut Fédératif de Recherche 3450, Université de Toulouse, CNRS, UPS, Plateforme Imagerie TRI-Genotoul, 31326 Castanet-Tolosan, France
| | - Tatiana Vernié
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, Auzeville, BP42617, 31326 Castanet-Tolosan, France
| | | | | | - Martin Parniske
- Genetics, Faculty of Biology, University of Munich (LMU), 82152 Martinsried, Germany
| | - Patrice Morel
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342 Lyon, France
| | - Michiel Vandenbussche
- Laboratoire Reproduction et Développement des Plantes, Université de Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRA, F-69342 Lyon, France
| | - Martine Schorderet
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Didier Reinhardt
- Department of Biology, University of Fribourg, 1700 Fribourg, Switzerland
| | - Pierre-Marc Delaux
- Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, Auzeville, BP42617, 31326 Castanet-Tolosan, France
| | - Jean-Jacques Bono
- LIPM, Université de Toulouse, INRA, CNRS, 31326 Castanet-Tolosan, France
| | - Benoit Lefebvre
- LIPM, Université de Toulouse, INRA, CNRS, 31326 Castanet-Tolosan, France.
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3
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Cao Y, Halane MK, Gassmann W, Stacey G. The Role of Plant Innate Immunity in the Legume-Rhizobium Symbiosis. ANNUAL REVIEW OF PLANT BIOLOGY 2017; 68:535-561. [PMID: 28142283 DOI: 10.1146/annurev-arplant-042916-041030] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
A classic view of the evolution of mutualism is that it derives from a pathogenic relationship that attenuated over time to a situation in which both partners can benefit. If this is the case for rhizobia, then one might uncover features of the symbiosis that reflect this earlier pathogenic state. For example, as with plant pathogens, it is now generally assumed that rhizobia actively suppress the host immune response to allow infection and symbiosis establishment. Likewise, the host has retained mechanisms to control the nutrient supply to the symbionts and the number of nodules so that they do not become too burdensome. The open question is whether such events are strictly ancillary to the central symbiotic nodulation factor signaling pathway or are essential for rhizobial host infection. Subsequent to these early infection events, plant immune responses can also be induced inside nodules and likely play a role in, for example, nodule senescence. Thus, a balanced regulation of innate immunity is likely required throughout rhizobial infection, symbiotic establishment, and maintenance. In this review, we discuss the significance of plant immune responses in the regulation of symbiotic associations with rhizobia, as well as rhizobial evasion of the host immune system.
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Affiliation(s)
- Yangrong Cao
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Morgan K Halane
- Division of Plant Sciences, C.S. Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211
| | - Walter Gassmann
- Division of Plant Sciences, C.S. Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211
| | - Gary Stacey
- Division of Plant Sciences, C.S. Bond Life Sciences Center, and Interdisciplinary Plant Group, University of Missouri, Columbia, Missouri 65211
- Division of Biochemistry, University of Missouri, Columbia, Missouri 65211;
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4
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Berthelot N, Brossay A, Gasciolli V, Bono JJ, Baron A, Beau JM, Urban D, Boyer FD, Vauzeilles B. Synthesis of lipo-chitooligosaccharide analogues and their interaction with LYR3, a high affinity binding protein for Nod factors and Myc-LCOs. Org Biomol Chem 2017; 15:7802-7812. [DOI: 10.1039/c7ob01201b] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Lipo-chitotetrasaccharide analogues have been synthesized from a derivative obtained by controlled chitin depolymerization and a functionalized N-acetyl-glucosamine.
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Affiliation(s)
- Nathan Berthelot
- Institut de Chimie des Substances Naturelles
- CNRS UPR2301
- Univ. Paris-Sud
- Université Paris-Saclay
- F-91198 Gif-sur-Yvette
| | - Antoine Brossay
- Institut de Chimie des Substances Naturelles
- CNRS UPR2301
- Univ. Paris-Sud
- Université Paris-Saclay
- F-91198 Gif-sur-Yvette
| | | | | | - Aurélie Baron
- Institut de Chimie des Substances Naturelles
- CNRS UPR2301
- Univ. Paris-Sud
- Université Paris-Saclay
- F-91198 Gif-sur-Yvette
| | - Jean-Marie Beau
- Institut de Chimie des Substances Naturelles
- CNRS UPR2301
- Univ. Paris-Sud
- Université Paris-Saclay
- F-91198 Gif-sur-Yvette
| | - Dominique Urban
- Institut de Chimie des Substances Naturelles
- CNRS UPR2301
- Univ. Paris-Sud
- Université Paris-Saclay
- F-91198 Gif-sur-Yvette
| | - François-Didier Boyer
- Institut de Chimie des Substances Naturelles
- CNRS UPR2301
- Univ. Paris-Sud
- Université Paris-Saclay
- F-91198 Gif-sur-Yvette
| | - Boris Vauzeilles
- Institut de Chimie des Substances Naturelles
- CNRS UPR2301
- Univ. Paris-Sud
- Université Paris-Saclay
- F-91198 Gif-sur-Yvette
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5
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Fliegmann J, Canova S, Lachaud C, Uhlenbroich S, Gasciolli V, Pichereaux C, Rossignol M, Rosenberg C, Cumener M, Pitorre D, Lefebvre B, Gough C, Samain E, Fort S, Driguez H, Vauzeilles B, Beau JM, Nurisso A, Imberty A, Cullimore J, Bono JJ. Lipo-chitooligosaccharidic symbiotic signals are recognized by LysM receptor-like kinase LYR3 in the legume Medicago truncatula. ACS Chem Biol 2013; 8:1900-6. [PMID: 23808871 DOI: 10.1021/cb400369u] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
While chitooligosaccharides (COs) derived from fungal chitin are potent elicitors of defense reactions, structurally related signals produced by certain bacteria and fungi, called lipo-chitooligosaccharides (LCOs), play important roles in the establishment of symbioses with plants. Understanding how plants distinguish between friend and foe through the perception of these signals is a major challenge. We report the synthesis of a range of COs and LCOs, including photoactivatable probes, to characterize a membrane protein from the legume Medicago truncatula. By coupling photoaffinity labeling experiments with proteomics and transcriptomics, we identified the likely LCO-binding protein as LYR3, a lysin motif receptor-like kinase (LysM-RLK). LYR3, expressed heterologously, exhibits high-affinity binding to LCOs but not COs. Homology modeling, based on the Arabidopsis CO-binding LysM-RLK AtCERK1, suggests that LYR3 could accommodate the LCO in a conserved binding site. The identification of LYR3 opens up ways for the molecular characterization of LCO/CO discrimination.
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Affiliation(s)
- Judith Fliegmann
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441,
31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes
(LIPM), UMR2594,
31326 Castanet-Tolosan, France
| | - Sophie Canova
- Université Paris-Sud and CNRS, Laboratoire de Synthèse de
Biomolécules, Institut de Chimie Moléculaire et des
Matériaux d’Orsay, UMR 8182, 91405 Orsay, France
| | - Christophe Lachaud
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441,
31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes
(LIPM), UMR2594,
31326 Castanet-Tolosan, France
| | - Sandra Uhlenbroich
- Université de Toulouse, UPS, UMR 5546, Laboratoire de Recherche
en Sciences Végétales (LRSV), BP 42617, 31326 Castanet-Tolosan,
France
- CNRS, UMR 5546, BP 42617, 31326 Castanet-Tolosan, France
| | - Virginie Gasciolli
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441,
31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes
(LIPM), UMR2594,
31326 Castanet-Tolosan, France
| | | | | | - Charles Rosenberg
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441,
31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes
(LIPM), UMR2594,
31326 Castanet-Tolosan, France
| | - Marie Cumener
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441,
31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes
(LIPM), UMR2594,
31326 Castanet-Tolosan, France
| | - Delphine Pitorre
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441,
31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes
(LIPM), UMR2594,
31326 Castanet-Tolosan, France
| | - Benoit Lefebvre
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441,
31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes
(LIPM), UMR2594,
31326 Castanet-Tolosan, France
| | - Clare Gough
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441,
31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes
(LIPM), UMR2594,
31326 Castanet-Tolosan, France
| | - Eric Samain
- Centre de Recherches sur les Macromolécules Végétales (CERMAV,
UPR-CNRS 5301), affiliated with the Université Joseph Fourier
(UJF) and member of the Institut de Chimie Moléculaire de Grenoble
(ICMG, FR-CNRS 2607), BP53, 38041 Grenoble Cedex 9, France
| | - Sébastien Fort
- Centre de Recherches sur les Macromolécules Végétales (CERMAV,
UPR-CNRS 5301), affiliated with the Université Joseph Fourier
(UJF) and member of the Institut de Chimie Moléculaire de Grenoble
(ICMG, FR-CNRS 2607), BP53, 38041 Grenoble Cedex 9, France
| | - Hugues Driguez
- Centre de Recherches sur les Macromolécules Végétales (CERMAV,
UPR-CNRS 5301), affiliated with the Université Joseph Fourier
(UJF) and member of the Institut de Chimie Moléculaire de Grenoble
(ICMG, FR-CNRS 2607), BP53, 38041 Grenoble Cedex 9, France
| | - Boris Vauzeilles
- Université Paris-Sud and CNRS, Laboratoire de Synthèse de
Biomolécules, Institut de Chimie Moléculaire et des
Matériaux d’Orsay, UMR 8182, 91405 Orsay, France
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles
du CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
| | - Jean-Marie Beau
- Université Paris-Sud and CNRS, Laboratoire de Synthèse de
Biomolécules, Institut de Chimie Moléculaire et des
Matériaux d’Orsay, UMR 8182, 91405 Orsay, France
- Centre de Recherche de Gif, Institut de Chimie des Substances Naturelles
du CNRS, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
| | - Alessandra Nurisso
- School of Pharmaceutical Sciences, UNIGE, Quai Ernest Ansermet 30, 1205 Geneva, Switzerland
| | - Anne Imberty
- Centre de Recherches sur les Macromolécules Végétales (CERMAV,
UPR-CNRS 5301), affiliated with the Université Joseph Fourier
(UJF) and member of the Institut de Chimie Moléculaire de Grenoble
(ICMG, FR-CNRS 2607), BP53, 38041 Grenoble Cedex 9, France
| | - Julie Cullimore
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441,
31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes
(LIPM), UMR2594,
31326 Castanet-Tolosan, France
| | - Jean-Jacques Bono
- INRA, Laboratoire des Interactions Plantes-Microorganismes (LIPM), UMR441,
31326 Castanet-Tolosan, France
- CNRS, Laboratoire des Interactions Plantes-Microorganismes
(LIPM), UMR2594,
31326 Castanet-Tolosan, France
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6
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Remans R, Snoeck C, Verreth C, Croonenborghs A, Luyten E, Ndayizeye M, Martínez-Romero E, Michiels J, Vanderleyden J. Inactivation of the nodH gene in Sinorhizobium sp. BR816 enhances symbiosis with Phaseolus vulgaris L. FEMS Microbiol Lett 2007; 266:210-7. [PMID: 17233732 DOI: 10.1111/j.1574-6968.2006.00521.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Sulfate modification on Rhizobium Nod factor signaling molecules is not a prerequisite for successful symbiosis with the common bean (Phaseolus vulgaris L.). However, many bean-nodulating rhizobia, including the broad host strain Sinorhizobium sp. BR816, produce sulfated Nod factors. Here, we show that the nodH gene, encoding a sulfotransferase, is responsible for the transfer of sulfate to the Nod factor backbone in Sinorhizobium sp. BR816, as was shown for other rhizobia. Interestingly, inactivation of nodH enables inoculated bean plants to fix significantly more nitrogen under different experimental setups. Our studies show that nodH in the wild-type strain is still expressed during the later stages of symbiosis. This is the first report on enhanced nitrogen fixation by blocking Nod factor sulfation.
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Affiliation(s)
- Roseline Remans
- Centre of Microbial and Plant Genetics, Kasteelpark Arenberg, Heverlee, Belgium
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7
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Stiens M, Schneiker S, Keller M, Kuhn S, Pühler A, Schlüter A. Sequence analysis of the 144-kilobase accessory plasmid pSmeSM11a, isolated from a dominant Sinorhizobium meliloti strain identified during a long-term field release experiment. Appl Environ Microbiol 2006; 72:3662-72. [PMID: 16672515 PMCID: PMC1472397 DOI: 10.1128/aem.72.5.3662-3672.2006] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genome of Sinorhizobium meliloti type strain Rm1021 consists of three replicons: the chromosome and two megaplasmids, pSymA and pSymB. Additionally, many indigenous S. meliloti strains possess one or more smaller plasmids, which represent the accessory genome of this species. Here we describe the complete nucleotide sequence of an accessory plasmid, designated pSmeSM11a, that was isolated from a dominant indigenous S. meliloti subpopulation in the context of a long-term field release experiment with genetically modified S. meliloti strains. Sequence analysis of plasmid pSmeSM11a revealed that it is 144,170 bp long and has a mean G+C content of 59.5 mol%. Annotation of the sequence resulted in a total of 160 coding sequences. Functional predictions could be made for 43% of the genes, whereas 57% of the genes encode hypothetical or unknown gene products. Two plasmid replication modules, one belonging to the repABC replicon family and the other belonging to the plasmid type A replicator region family, were identified. Plasmid pSmeSM11a contains a mobilization (mob) module composed of the type IV secretion system-related genes traG and traA and a putative mobC gene. A large continuous region that is about 42 kb long is very similar to a corresponding region located on S. meliloti Rm1021 megaplasmid pSymA. Single-base-pair deletions in the homologous regions are responsible for frameshifts that result in nonparalogous coding sequences. Plasmid pSmeSM11a carries additional copies of the nodulation genes nodP and nodQ that are responsible for Nod factor sulfation. Furthermore, a tauD gene encoding a putative taurine dioxygenase was identified on pSmeSM11a. An acdS gene located on pSmeSM11a is the first example of such a gene in S. meliloti. The deduced acdS gene product is able to deaminate 1-aminocyclopropane-1-carboxylate and is proposed to be involved in reducing the phytohormone ethylene, thus influencing nodulation events. The presence of numerous insertion sequences suggests that these elements mediated acquisition of accessory plasmid modules.
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Affiliation(s)
- M Stiens
- Fakultät für Biologie, Lehrstuhl für Genetik, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany
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8
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Hogg BV, Cullimore JV, Ranjeva R, Bono JJ. The DMI1 and DMI2 early symbiotic genes of medicago truncatula are required for a high-affinity nodulation factor-binding site associated to a particulate fraction of roots. PLANT PHYSIOLOGY 2006; 140:365-73. [PMID: 16377749 PMCID: PMC1326057 DOI: 10.1104/pp.105.068981] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2005] [Revised: 11/14/2005] [Accepted: 11/15/2005] [Indexed: 05/05/2023]
Abstract
The establishment of the legume-rhizobia symbiosis between Medicago spp. and Sinorhizobium meliloti is dependent on the production of sulfated lipo-chitooligosaccharidic nodulation (Nod) factors by the bacterial partner. In this article, using a biochemical approach to characterize putative Nod factor receptors in the plant host, we describe a high-affinity binding site (Kd = 0.45 nm) for the major Nod factor produced by S. meliloti. This site is termed Nod factor-binding site 3 (NFBS3). NFBS3 is associated to a high-density fraction prepared from roots of Medicago truncatula and shows binding specificity for lipo-chitooligosaccharidic structures. As for the previously characterized binding sites (NFBS1 and NFBS2), NFBS3 does not recognize the sulfate group on the S. meliloti Nod factor. Studies of Nod factor binding in root extracts of early symbiotic mutants of M. truncatula reveals that the new site is present in Nod factor perception and does not make infections 3 (dmi3) mutants but is absent in dmi1 and dmi2 mutants. Roots and cell cultures of all these mutants still contain sites similar to NFBS1 and NFBS2, respectively. These results suggest that NFBS3 is different from NFBS2 and NFBS1 and is dependent on the common symbiotic genes DMI1 and DMI2 required for establishment of symbioses with both rhizobia and arbuscular mycorrhizal fungi. The potential role of this site in the establishment of root endosymbioses is discussed.
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Affiliation(s)
- Bridget V Hogg
- Surfaces Cellulaires et Signalisation chez les Végétaux, Unité Mixte de Recherche 5546 Centre National de la Recherche Scientifique-Université Paul Sabatier, Toulouse III, Pôle de Biotechnologie Végétale, 31326 Castanet-Tolosan, France
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