title: Covalently linked hopanoid-lipid A improves outer-membrane resistance of a Bradyrhizobium symbiont of legumes.
abstract: Lipopolysaccharides (LPSs) are major components of the outer membrane of Gram-negative bacteria and are essential for their growth and survival. They act as a structural barrier and play an important role in the interaction with eukaryotic hosts. Here we demonstrate that a photosynthetic Bradyrhizobium strain, symbiont of Aeschynomene legumes, synthesizes a unique LPS bearing a hopanoid covalently attached to lipid A. Biophysical analyses of reconstituted liposomes indicate that this hopanoid-lipid A structure reinforces the stability and rigidity of the outer membrane. In addition, the bacterium produces other hopanoid molecules not linked to LPS. A hopanoid-deficient strain, lacking a squalene hopene cyclase, displays increased sensitivity to stressful conditions and reduced ability to survive intracellularly in the host plant. This unusual combination of hopanoid and LPS molecules may represent an adaptation to optimize bacterial survival in both free-living and symbiotic states.
authors.affiliation: Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant'Angelo, Università di Napoli Federico II, Via Cintia 4, Napoli I-80126, Italy.
authors.forename: Alba
authors.initials: A
authors.lastname: Silipo
authors.affiliation: Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant'Angelo, Università di Napoli Federico II, Via Cintia 4, Napoli I-80126, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Vitiello
authors.affiliation: IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRA/UM2/CIRAD, TA-A82/J, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
authors.forename: Djamel
authors.initials: D
authors.lastname: Gully
authors.affiliation: CNR-Istituto per i Polimeri, Compositi e Biomateriali IPCB, Unità di Catania Via P. Gaifami 18, Catania 95126, Italy.
authors.forename: Luisa
authors.initials: L
authors.lastname: Sturiale
authors.affiliation: IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRA/UM2/CIRAD, TA-A82/J, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
authors.forename: Clémence
authors.initials: C
authors.lastname: Chaintreuil
authors.affiliation: IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRA/UM2/CIRAD, TA-A82/J, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
authors.forename: Joel
authors.initials: J
authors.lastname: Fardoux
authors.affiliation: CIRAD, UMR BGPI, Montpellier F-34398, France.
authors.forename: Daniel
authors.initials: D
authors.lastname: Gargani
authors.affiliation: Department of Biology, University of Texas, Arlington, Texas, USA.
authors.forename: Hae-In
authors.initials: HI
authors.lastname: Lee
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology and Howards Hughes Medical Institute, Pasadena, California 91125, USA.
authors.forename: Gargi
authors.initials: G
authors.lastname: Kulkarni
authors.affiliation: IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRA/UM2/CIRAD, TA-A82/J, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Busset
authors.affiliation: Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant'Angelo, Università di Napoli Federico II, Via Cintia 4, Napoli I-80126, Italy.
authors.forename: Roberta
authors.initials: R
authors.lastname: Marchetti
authors.affiliation: CNR-Istituto per i Polimeri, Compositi e Biomateriali IPCB, Unità di Catania Via P. Gaifami 18, Catania 95126, Italy.
authors.forename: Angelo
authors.initials: A
authors.lastname: Palmigiano
authors.affiliation: Division of Bioanalytical Chemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a/c, D-23845 Borstel, Germany.
authors.forename: Herman
authors.initials: H
authors.lastname: Moll
authors.affiliation: Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a/c, D-23845 Borstel, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Engel
authors.affiliation: Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant'Angelo, Università di Napoli Federico II, Via Cintia 4, Napoli I-80126, Italy.
authors.forename: Rosa
authors.initials: R
authors.lastname: Lanzetta
authors.affiliation: Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant'Angelo, Università di Napoli Federico II, Via Cintia 4, Napoli I-80126, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Paduano
authors.affiliation: Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant'Angelo, Università di Napoli Federico II, Via Cintia 4, Napoli I-80126, Italy.
authors.forename: Michelangelo
authors.initials: M
authors.lastname: Parrilli
authors.affiliation: 1] Department of Biology, University of Texas, Arlington, Texas, USA [2] Division of Biotechnology, College of Environmental and Bioresource Sciences, Chonbuk National University, Iksan 570-752, Republic of Korea.
authors.forename: Woo-Suk
authors.initials: WS
authors.lastname: Chang
authors.affiliation: Division of Structural Biochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 4a/c, D-23845 Borstel, Germany.
authors.forename: Otto
authors.initials: O
authors.lastname: Holst
authors.affiliation: Division of Biology and Biological Engineering, California Institute of Technology and Howards Hughes Medical Institute, Pasadena, California 91125, USA.
authors.forename: Dianne K
authors.initials: DK
authors.lastname: Newman
authors.affiliation: CNR-Istituto per i Polimeri, Compositi e Biomateriali IPCB, Unità di Catania Via P. Gaifami 18, Catania 95126, Italy.
authors.forename: Domenico
authors.initials: D
authors.lastname: Garozzo
authors.affiliation: Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant'Angelo, Università di Napoli Federico II, Via Cintia 4, Napoli I-80126, Italy.
authors.forename: Gerardino
authors.initials: G
authors.lastname: D'Errico
authors.affiliation: IRD, Laboratoire des Symbioses Tropicales et Méditerranéennes (LSTM), UMR IRD/SupAgro/INRA/UM2/CIRAD, TA-A82/J, Campus de Baillarguet, 34398 Montpellier cedex 5, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Giraud
authors.affiliation: Dipartimento di Scienze Chimiche, Complesso Universitario Monte Sant'Angelo, Università di Napoli Federico II, Via Cintia 4, Napoli I-80126, Italy.
authors.forename: Antonio
authors.initials: A
authors.lastname: Molinaro
mesh_terms: D020369:Bradyrhizobium / Q000502:physiology*; D007887:Fabaceae / Q000382:microbiology* / Q000648:ultrastructure; D008050:Lipid A / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D055170:Plant Root Nodulation; D053204:Root Nodules, Plant / Q000382:microbiology* / Q000648:ultrastructure; D013559:Symbiosis; D014315:Triterpenes / Q000378:metabolism*
chemical_list: D008050:Lipid A; D014315:Triterpenes; C025206:hopane