Effect of Bradyrhizobium photosynthesis on stem nodulation of Aeschynomene sensitiva.
Some leguminous species of the genus Aeschynomene are specifically stem-nodulated by photosynthetic bradyrhizobia. To study the effect of bacterial photosynthesis during symbiosis, we generated a photosynthesis-negative mutant of the Bradyrhizobium sp. strain ORS278 symbiont of Aeschynomene sensitiva. The presence of a functional photosynthetic unit in bacteroids and the high expression of the photosynthetic genes observed in stem nodules demonstrate that the bacteria are photosynthetically active during stem symbiosis. Stem inoculation by the photosynthetic mutant gave a 50% decrease in stem-nodule number, which reduced nitrogen fixation activity and plant growth in the same proportion. These results indicate an important role of bacterial photosynthesis in the efficiency of stem nodulation.
Giraud
E
E
Laboratoire des Symbioses Tropicales et Méditerranéennes, Institut de Recherche pour le Développement, Centre de Coopération Internationale en Recherche Agronomique pour le Développement, Ecole Nationale d'Agronomie de Montpellier, Cedex, France.
Hannibal
L
L
Fardoux
J
J
Verméglio
A
A
Dreyfus
B
B
D001426:Bacterial Proteins; D001483:Base Sequence; D020369:Bradyrhizobium / Q000235:genetics / Q000502:physiology*; D004269:DNA, Bacterial; D007887:Fabaceae / Q000382:microbiology*; D015870:Gene Expression; D006419:Heme Oxygenase (Decyclizing) / Q000235:genetics / Q000378:metabolism; D045342:Light-Harvesting Protein Complexes; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009876:Operon; D010641:Phenotype; D010788:Photosynthesis / Q000502:physiology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics / Q000378:metabolism*; D010946:Plants, Medicinal; D013559:Symbiosis
D001426:Bacterial Proteins; D004269:DNA, Bacterial; D045342:Light-Harvesting Protein Complexes; D045322:Photosynthetic Reaction Center Complex Proteins; C096433:PufL protein, Bacteria; C098543:PufM protein, Bacteria; D006419:Heme Oxygenase (Decyclizing); C104107:HmuO protein, bacteria