Mécanismes moléculaires de la spécificité de la symbiose Frankia-Myrica gale : nature et rôles des métabolites secondaires de la plante-hôtes
Auteur / Autrice : | Jean Popovici |
Direction : | Gilles Comte, Maria P Fernandez |
Type : | Thèse de doctorat |
Discipline(s) : | Écologie microbienne |
Date : | Soutenance en 2008 |
Etablissement(s) : | Lyon 1 |
Mots clés
Mots clés contrôlés
Résumé
The molecular mechanisms involved in the establishment and the specificity of the nitrogen-fixing symbiosis associating Frankia genus bacteria and actinorhizal plants are still unknown. The plant model chosen, Myrica gale, allows, due to its original symbiotic specificity compared to other Myricaceae species, to compare compatible and incompatible interactions. This work focused on the role of the host plant secondary metabolites in the symbiotic specificity. Two approaches were developed in this work: 1 the purification, identification and study of the effect of seed-exudated compounds on the physiology of compatible and incompatible Frankia strains (growth, nitrogen fixation and gene expression) and 2 the effect of the inoculation of compatible and incompatible Frankia strains on the root phenolic metabolism of the host-plant. The results of this work show the involvement of the host-plant secondary metabolites and particularly dihydrochalcones, in the symbiotic interaction with Frankia