%0 Journal Article
%9 ACL : Articles dans des revues avec comité de lecture non répertoriées par l'AERES
%A Chaintreuil, Clémence
%A Giraud, Eric
%A Prin, Yves
%A Lorquin, Jean
%A Bâ, A.
%A Gillis, M.
%A Lajudie, Philippe de
%A Dreyfus, Bernard
%T Photosynthetic bradyrhizobia are natural endophytes of the African wild rice Oryza breviligulata
%D 2000
%L fdi:010023750
%G ENG
%J Applied and Environmental Microbiology
%@ 0099-2240
%K BACTERIE ; ENDOPHYTE ; RIZ ; RACINE ; NODULE RACINAIRE ; SYMBIOSE ; PHOTOSYNTHESE ; FIXATION BIOLOGIQUE DE L'AZOTE ; INOCULATION ; CULTURE DE MICROORGANISME ; ETUDE EXPERIMENTALE
%K SENEGAL ; GUINEE
%N 12
%P 5437-5447
%R 10.1128/AEM.66.12.5437-5447.2000
%U https://www.documentation.ird.fr/hor/fdi:010023750
%> https://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/b_fdi_57-58/010023750.pdf
%V 66
%W Horizon (IRD)
%X We investigated the presence of endophytic rhizobia within the roots of the wetland wild rice #Oryza breviligulata$, which is the ancestor of the African cultivated rice #Oryza glaberrima$. This primitive rice species grows in the same wetland sites as #Aeschynomene sensitiva$, an aquatic stem-nodulated legume associated with photosynthetic strains of #Bradyrhizobium$. Twenty endophytic and aquatic isolates were obtained at three different sites in West Africa (Senegal and Guinea) from nodal roots of #O. breviligulata$ and surrounding water by using #A. sensitiva$ as a trap legume. Most endophytic and aquatic isolates were photosynthetic and belonged to the same phylogenetic #Bradyrhizobium$/#Blastobacter$ subgroup as the typical photosynthetic #Bradyrhizobium$ strains previously isolated from #Aeschynomene$ stem nodules. Nitrogen-fixing activity, measured by acetylene reduction, was detected in rice plants inoculated with endophytic isolates. A 20% increase in the shoot growth and grain yield of #O. breviligulata$ grown in a greenhouse was also observed upon inoculation with one endophytic strain and one #Aeschynomene$ photosynthetic strain. The photosynthetic #Bradyrhizobium$ sp. ORS278 extensively colonized the root surface, followed by intercellular, and rarely intracellular, bacterial invasion of the rice roots, which was determined with a lacZ-tagged mutant of ORS278. The discovery that photosynthetic #Bradyrhisobium$ strains, which are usually known to induce nitrogen-fixing nodules on stems of the legume #Aeschynomene, are also natural true endophytes of the primitve rice #O. breviligulata$ could significantly enhance cultivated rice production. (Résumé d'auteur)
%$ 084SYMBIO01