References of "Jourdan, Emmanuel"
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See detailAmino Acids, Iron, and Growth Rate as Key Factors Influencing Production of the Pseudomonas Putida Btp1 Benzylamine Derivative Involved in Systemic Resistance Induction in Different Plants
Ongena, MARC ULg; Jourdan, Emmanuel ULg; Adam, Akram et al

in Microbial Ecology (2008), 55(2), 280-92

The biological control bacterium Pseudomonas putida BTP1 exerts its protective effect mostly by inducing an enhanced state of resistance in the host plant against pathogen attack [induced systemic ... [more ▼]

The biological control bacterium Pseudomonas putida BTP1 exerts its protective effect mostly by inducing an enhanced state of resistance in the host plant against pathogen attack [induced systemic resistance (ISR)]. We previously reported that a specific compound derived from benzylamine may be involved in the elicitation of the ISR phenomenon by this Pseudomonas strain. In this article, we provide further information about the N,N-dimethyl-N-tetradecyl-N-benzylammonium structure of this determinant for ISR and show that the benzylamine moiety may be important for perception of the molecule by root cells of different plant species. We also investigated some regulatory aspects of elicitor production with the global aim to better understand how in situ expression of these ISR elicitors can be modulated by physiological and environmental factors. The biosynthesis is clearly related to secondary metabolism, and chemostat experiments showed that the molecule is more efficiently produced at low cell growth rate. Interestingly, the presence of free amino acids in the environment is necessary for optimal production, and a specific positive effect of phenylalanine was evidenced in pulsed continuous cultures. The influence of other abiotic factors, such as mineral content, oxygen concentration, or pH, on elicitor production is also reported and discussed with respect to the specific conditions that the producing strain undergoes in the rhizosphere environment. [less ▲]

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See detailCaractéristiques moléculaires de l'immunité des plantes induite par les rhizobactéries non pathogènes
Jourdan, Emmanuel ULg; Ongena, MARC ULg; Thonart, Philippe ULg

in Biotechnologie, Agronomie, Société et Environnement = Biotechnology, Agronomy, Society and Environment [=BASE] (2008), 12(4), 437-449

La reconnaissance par la plante de certaines bactéries de la rhizosphère peut conduire à une réaction d'immunisation lui permettant de mieux se défendre vis-à-vis d'une attaque ultérieure par un organisme ... [more ▼]

La reconnaissance par la plante de certaines bactéries de la rhizosphère peut conduire à une réaction d'immunisation lui permettant de mieux se défendre vis-à-vis d'une attaque ultérieure par un organisme pathogène. Utilisé en combinaison avec d'autres approches phytosanitaires, ce phénomène d'induction de résistance systémique (lSR) par les rhizobactéries est considéré comme une stratégie prometteuse dans la lutte biologique contre les maladies des cultures. Cet article présente les aspects moléculaires intervenant à chacune des trois étapes de ce processus, c'est-à-dire la perception des éliciteurs bactériens par les cellules de la plante, la transmission d'un signal nécessaire pour propager l'état induit dans tous les organes de la plante et l'expression des mécanismes de défense proprement dits qui vont limiter ou inhiber la pénétration du pathogène dans les tissus infectés. L'état des connaissances sur l'ISR est exposé en parallèle avec les informations dont on dispose concernant la résistance systémique acquise qui est similaire d'un point de vue phénotypique mais qui est induite suite à une interaction incompatible avec un agent pathogène. [less ▲]

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See detailThe systemic resistance induced in tomato by a non-pathogenic Pseudomonas strain is associated with the stimulation of the lipoxygenase pathway
Adam, Akram; Duby, Franceline ULg; Ongena, MARC ULg et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2007), 30

Root treatment by the non-pathogenic Pseudomonas putida strain BTP1 reduced by 34% the disease caused by Botrytis cinerea on tomato leaves. This induced systemic resistance phenomenon is associated both ... [more ▼]

Root treatment by the non-pathogenic Pseudomonas putida strain BTP1 reduced by 34% the disease caused by Botrytis cinerea on tomato leaves. This induced systemic resistance phenomenon is associated both with the accumulation of fungitoxic material and with the stimulation of the lipoxygenase pathway in infected leaves. More precisely, we observed a consistent change in the expression of a new tomloxF gene in the leaves from BTP1-treated plants as far as the pathogen is introduced. This suggests that the roots were primed and reacted locally to colonization by bacteria and that defense-related gene expression is turned on systemically upon pathogen perception [less ▲]

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See detailPGPR-induced systemic resistance: activity of amphiphilic elicitors and structural analogues on different plant species
Jourdan, Emmanuel ULg; Ongena, MARC ULg; Adam, Akram et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2007), 30

Some non pathogenic microorganisms can induce disease resistance mechanisms expressed systemically in the host plant thereby rendering it less susceptible to further attack by pathogens. In this study, we ... [more ▼]

Some non pathogenic microorganisms can induce disease resistance mechanisms expressed systemically in the host plant thereby rendering it less susceptible to further attack by pathogens. In this study, we have investigated the role of bacterial compounds as elicitors of the induced systemic resistance. Lipopeptides, especially surfactin and fengycin, produced by Bacillus subtilis strains are able to stimulate bean and tomato plants and decrease the impact of subsequent pathogen infection. Preliminary experiments on tobacco cells showed that surfactine induces some modifications in the phenylpropanoid pathway. Amphiphilic properties of lipopeptides and NABD, the elicitor isolated from Pseudomonas putida strain BTP1, could be responsible for their activities on plant cells [less ▲]

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See detailSurfactin and fengycin lipopeptides of Bacillus subtilis as elicitors of induced systemic resistance in plants
Ongena, MARC ULg; Jourdan, Emmanuel ULg; Adam, Akram ULg et al

in Environmental Microbiology (2007), 9(4), 1084-1090

Multiple strains of Bacillus spp. were demonstrated to stimulate plant defence responses. However, very little is known about the nature of molecular determinants secreted by these Gram-positive bacteria ... [more ▼]

Multiple strains of Bacillus spp. were demonstrated to stimulate plant defence responses. However, very little is known about the nature of molecular determinants secreted by these Gram-positive bacteria that are responsible for the elicitation of the induced systemic resistance (ISR) phenomenon. This study shows that the lipopeptides surfactins and fengycins may be involved in this elicitation process. In bean, pure fengycins and surfactins provided a significant ISR-mediated protective effect on bean plants, similar to the one induced by living cells of the producing strain S499. Moreover, experiments conducted on bean and tomato plants showed that overexpression of both surfactin and fengycin biosynthetic genes in the naturally poor producer Bacillus subtilis strain 168 was associated with a significant increase in the potential of the derivatives to induce resistance. In tomato cells, key enzymes of the lipoxygenase pathway appeared to be activated in resistant plants following induction by lipopeptide overproducers. To our knowledge, such lipopeptides constitute a novel class of compounds from non-pathogenic bacteria that can be perceived by plant cells as signals to initiate defence mechanisms. [less ▲]

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See detailRole of lipopeptides in the biological control activity of Bacillus subtilis
Jourdan, Emmanuel ULg; Ongena, Marc ULg; Adam, A. et al

Poster (2006, May)

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See detailPhysiological and physico-chemical factors modulating ISR elicitor production by Pseudomonas putida
Jourdan, Emmanuel ULg; Ongena, MARC ULg; Adam, Akram et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2006), 29(2)

Abstract: A better understanding of biotic and environmental factors that regulate the production of active metabolites by beneficial rhizobacteria is crucial for optimising biocontrol under pratical ... [more ▼]

Abstract: A better understanding of biotic and environmental factors that regulate the production of active metabolites by beneficial rhizobacteria is crucial for optimising biocontrol under pratical conditions. In this study, we wanted to evaluate the effect of some parameters on the production of the plant defence elicitor synthesized by Pseudomonas putida BTP1. This molecule is clearly dependant of the secondary metabolism and chemostat experiments showed that the elicitor is more efficiently produced at a very low cell growth rate. On another hand, the presence of free amino acids in the medium is necessary to obtain an optimal NABD production. A specific positive effect of phenylalanine was evidenced in pulsed continuous cultures suggesting that this residue could play a role as a precursor and/or act as a regulator in the biosynthetic pathway. [less ▲]

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See detailResistance induced in cucumber and tomato by a non-pathogenic Pseudomonas putida strain
Adam, Akram; Jourdan, Emmanuel ULg; Ongena, MARC ULg et al

in Parasitica (2005), 61

Some plant growth promoting rhizobacteria are able to stimulate inducible defense mechanisms that render the host plant less susceptible to a subsequent pathogen attack. This phenomenon, called induced ... [more ▼]

Some plant growth promoting rhizobacteria are able to stimulate inducible defense mechanisms that render the host plant less susceptible to a subsequent pathogen attack. This phenomenon, called induced systemic resistance (ISR), can occur in several plant species against a wide range of bacterial, viral and fungal pathogens. Despite extensive work, many aspects of the molecular basis underlying this rhizobacteria-mediated ISR remain unclear. In this context, we have studied for several years the ISR-mediated protective effect of a particular strain, Pseudomonas putida BTP1. In this paper, we present the results obtained by using BTP1 for disease reduction against anthracnose caused by Colletotrichum lagenarium on cucumber and grey mold caused by Botrytis cinerea on tomato. As a result of cucumber treatment with BTP1, we observed an enhanced hydroperoxide lyase activity that could restrict pathogen ingress since this enzyme, acting downstream in the so-called oxylipin pathway, forms short chain aldehydes considered as “volatile phytoalexins”. By contrast, this phenomenon is not involved in the protective effect afforded by the strain in tomato. In this case, disease reduction is more seemingly associated with an early accumulation of antifungal compounds stimulated by the bacterium, showing that specific ISR-related metabolic pathways may be activated in different plants by the same microorganism. [less ▲]

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See detailIsolation of an n-alkylated benzylamine derivative from Pseudomonas putida BTP1 as elicitor of induced systemic resistance in bean
Ongena, MARC ULg; Jourdan, Emmanuel ULg; Schafer, M. et al

in Molecular Plant-Microbe Interactions (2005), 18(6), 562-569

Root treatment of Phaseolus vulgaris with the nonpathogenic Pseudomonas putida BTP1 led to significant reduction of the disease caused by the pathogen Botrytis cinerea on leaves. The molecular determinant ... [more ▼]

Root treatment of Phaseolus vulgaris with the nonpathogenic Pseudomonas putida BTP1 led to significant reduction of the disease caused by the pathogen Botrytis cinerea on leaves. The molecular determinant of P putida BTP1 mainly responsible for the induced systemic resistance (ISR) was isolated from cell-free culture fluid after growth of the strain in the iron-poor casamino acid medium. Mass spectrometry analyses performed on both the bacterial product and synthetic analogues revealed a polyalkylated benzylamine structure, with the quaternary ammonium substituted by methyl, ethyl, and C-13 aliphatic groups responsible for the relative hydrophobicity of the molecule. The specific involvement of the N-alkylated benzylamine derivative (NABD) in ISR elicitation was first evidenced by testing the purified compound that mimicked the protective effect afforded by crude supernatant samples. The evidence was supported by the loss of elicitor activity of mutants impaired in NABD biosynthesis. Our experiments also showed that other iron-regulated metabolites secreted by the strain are not involved in ISR stimulation. Thus, these results indicate a wider variety of Pseudomonas determinants for ISR than reported to date. [less ▲]

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See detailStudy of a novel elicitor produced by Pseudomonas putida BTP1 in the ISR on bean
Jourdan, Emmanuel ULg; Ongena, Marc ULg; Schaffer, M. et al

Poster (2004, December 17)

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