Covalently linked hopanoid-lipid A improves outer-membrane resistance of a Bradyrhizobium symbiont of legumes

2014

Article référencé dans le Web of Science WOS:000343979300003

Silipo A., Vitiello G., Gully Djamel, Sturiale L., Chaintreuil Clémence, Fardoux Joël, Gargani D., Lee H. I., Kulkarni G., Busset N., Marchetti R., Palmigiano A., Moll H., Engel R., Lanzetta R., Paduano L., Parrilli M., Chang W. S., Holst O., Newman D. K., Garozzo D., D'Errico G., Giraud Eric, Molinaro A.

Nature Communications, 2014, 5, 5106 ISSN 2041-1723

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 intra-cellularly 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.

Sciences fondamentales / Techniques d'analyse et de recherche [020] ; Biotechnologies [084]

Fonds IRD [F B010062689]

fdi:010062689