Modulation de l'expression du pouvoir pathogène de Botrytis fabae Sard. et de Botrytis cinerea Pers. par des bactéries du phylloplan de Vicia faba L

La formation et le développement de lésions nécrotiques par Botrytis fabae et B. cinerea sur feuilles détachées de Vicia faba sont inhibés par la présence de sulfate ferrique dans la goutte d’inoculum. Le sulfate ferrique n’a pas d’effet sur la germination des conidies de Botrytis sur lames de verre, mais entraîne une forte stimulation de la croissance des tubes germinatifs. L’inhibition observée sur les feuilles détachées ne s’explique pas par la production de phytoalexines ni par la stimulation des réactions de défense de la plante. Par contre, les modifications relevées dans la composition de la microflore du phylloplan paraissent essentielles. Deux bactéries prédominantes suivant les conditions ont été isolées. Pseudomonas fluorescens est isolé dans les gouttes d’inoculum donnant des lésions, alors qu’en présence de sulfate ferrique - et donc en l’absence de lésions - c’est Erwinia herbicola qui devient majoritaire. Sur milieu de KING B, Pseudomonas exerce une antibiose vis-à-vis d’Erwinia. D’autre part, Erwinia inhibe la germination des conidies ainsi que la croissance des tubes germinatifs des Botrytis lors de tests in vitro. Mais on note également que l’inhibition des lésions due au sulfate de fer est presque totalement annulée par l’addition de Pseudomonas à l’inoculum. Le mode d’action du fer est discuté en terme d’avantage sélectif procuré à E. herbicola par rapport à P. fluorescens.Initiation and development of necrotic lesions by Botrytis fabae and B. cinerea on detached leaves of Vicia faba was inhibited by ferric sulfate in inoculum drops. Ferric sulfate had no effect on conidial germination of the two species on glass slides but a high stimulation of germ-tube growth was observed in the presence of iron. The inhibition observed on detached leaves could not be explained by phytoalexin production or by the stimulation of defence reactions in the plant. However, modifications in the microbial composition of the phyllophane flora seemed to play an important role. Two predominant bacteria were isolated under different conditions. Pseudomonas fluorescens was obtained from inoculum drops over developing necrotic lesions while Erwinia herbicola became dominant in ferric sulfate drops without necrotic lesions. On KING B medium, the P. fluorescens strain inhibited growth of E. herbicola, while in turn Erwinia inhibited conidial germination and germ tube growth of both Botrytis sp. on glass slides. Finally the inhibition of lesion development by ferric sulfate was almost completely suppressed by addition of the Pseudomonas strain to the inoculum. The mode of action of iron is discussed in terms of the selective advantage given to E. herbicola against P. fluorescens

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ASTOOL: A VO Compliant Tool for Image and Catalogue Astrometry

International audienceWe present ASTOOL which offers easy access to a set of astrometric tools using the VO compliant protocol UWS (Universal Worker Service

ASTOOL: A VO Compliant Tool for Image and Catalogue Astrometry

International audienceWe present ASTOOL which offers easy access to a set of astrometric tools using the VO compliant protocol UWS (Universal Worker Service

Services at VO-Paris Data Centre

International audienceAfter introducing the objectives of the new VO-Paris Data Centre, we present two implementations of services available to the community: 1) A portal for mosaicing digitized plate surveys and 2) a VO client dedicated to numerical simulation

Services at VO-Paris Data Centre

International audienceAfter introducing the objectives of the new VO-Paris Data Centre, we present two implementations of services available to the community: 1) A portal for mosaicing digitized plate surveys and 2) a VO client dedicated to numerical simulation

Development of a functional dairy snack containing oleoylethanolamide that reduces food intake in normal-weight and obese minipigs

Oleoylethanolamide (OEA) is a safe bioactive lipid that demonstrated strong anorexigenic properties in preclinical and clinical models. In order to evaluate the importance of OEA delivery kinetic on its anorectic properties, we developed OEA-containing dairy snacks with either a liquid or a semi-solid form. The OEA+ liquid snack, but not the semi-solid one, reduced by 14 and 18 % the amount of feed eaten by normal-weight and obese minipigs, respectively, in an eating behavior test performed 4 h after snack ingestion. In vitro digestion experiments revealed that OEA release in intestinal digesta was greatly enhanced when the snack was liquid compared to the semi-solid structure. Kinetic investigations of several plasma parameters after liquid snack ingestion points towards different potential mechanism depending upon the minipig weight status, with an effect of the OEA+ liquid snack likely on endocannabinoid and other related N-acylethanolamine metabolism in normal-weight minipigs and on ketogenesis in obese ones