References of "Ongena, Marc"
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See detailSugar beet leaves as new source of hydroperoxide lyase in a bioprocess producing green-note aldehydes.
Rabetafika, Holy-Nadia ULg; Gigot, Cédric ULg; Fauconnier, Marie-Laure ULg et al

in Biotechnology Letters (2008), 30(6), 1115-9

Hydroperoxide lyase activity was found in sugar beet leaves. Its optimum pH and temperature were, respectively, 6.7 and 22 degrees C. Under these conditions, conversion of linolenic acid 13-hydroperoxide ... [more ▼]

Hydroperoxide lyase activity was found in sugar beet leaves. Its optimum pH and temperature were, respectively, 6.7 and 22 degrees C. Under these conditions, conversion of linolenic acid 13-hydroperoxide to cis-3-hexenal with a maximum yield of 80% was reached after only 2 min. The stability of cis-3-hexenal was improved by acidifying the reaction medium. Based on these studies, a bioprocess producing green-note aldehydes in a laboratory-scale was achieved. [less ▲]

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See detailSystemic resistance induction in tomato by Pseudomonas putida BTP1: investigation of defense pathways.
Mariutto, M.; Duby, Franceline ULg; Ongena, Marc ULg et al

in Journal of Plant Pathology [=JPP] (2008), 90

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See detailEcological fitness of plant-beneficial Bacillus subtilis strains in soil: influence of rhizosphere specific parameters on surfactin synthesis.
Nihorimbere, V.; Fickers, P.; Thonart, Philippe ULg et al

in Journal of Plant Pathology [=JPP] (2008), 90

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See detailDefence responses induced in tobacco cells by Bacillus lipopeptides acting as elicitors of systemic resistance in plants
Henry, G.; Jourdan, E.; Thonart, Philippe ULg et al

in Journal of Plant Pathology [=JPP] (2008), 90

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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 detailSystemic resistance and lipoxygenase-related defence response induced in tomato by Pseudomonas putida strain BTP1.
Akram, Adam; Ongena, MARC ULg; Duby, Franceline et al

in BMC Plant Biology (2008), 8

BACKGROUND: Previous studies showed the ability of Pseudomonas putida strain BTP1 to promote induced systemic resistance (ISR) in different host plants. Since ISR is long-lasting and not conducive for ... [more ▼]

BACKGROUND: Previous studies showed the ability of Pseudomonas putida strain BTP1 to promote induced systemic resistance (ISR) in different host plants. Since ISR is long-lasting and not conducive for development of resistance of the targeted pathogen, this phenomenon can take part of disease control strategies. However, in spite of the numerous examples of ISR induced by PGPR in plants, only a few biochemical studies have associated the protective effect with specific host metabolic changes. RESULTS: In this study, we showed the protective effect of this bacterium in tomato against Botrytis cinerea. Following treatment by P. putida BTP1, analyses of acid-hydrolyzed leaf extracts showed an accumulation of antifungal material after pathogen infection. The fungitoxic compounds thus mainly accumulate as conjugates from which active aglycones may be liberated through the activity of hydrolytic enzymes. These results suggest that strain BTP1 can elicit systemic phytoalexin accumulation in tomato as one defence mechanism. On another hand, we have shown that key enzymes of the lipoxygenase pathway are stimulated in plants treated with the bacteria as compared with control plants. Interestingly, this stimulation is observed only after pathogen challenge in agreement with the priming concept almost invariably associated with the ISR phenomenon. CONCLUSION: Through the demonstration of phytoalexin accumulation and LOX pathway stimulation in tomato, this work provides new insights into the diversity of defence mechanisms that are inducible by non-pathogenic bacteria in the context of ISR. [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 detailEffect of monopropylene glycol and gamma irradiation on Yarrowia lipolytica lipase stabilization
Alloué, Wazé Aimée Mireille; Destain, Jacqueline ULg; Ongena, Marc ULg et al

in Preparative Biochemistry & Biotechnology (2008), 38(3), 217-228

This work investigated the effects of monopropylene glycol, protease inhibitor, and gamma irradiation on Yarrowia lipolytica lipase stability during storage. Enzyme liquid stabilization was achieved by ... [more ▼]

This work investigated the effects of monopropylene glycol, protease inhibitor, and gamma irradiation on Yarrowia lipolytica lipase stability during storage. Enzyme liquid stabilization was achieved by addition of monopropylene glycol (MPG) at respective concentrations of 50, 75, and 90%, the protease inhibitors (P2714 and P8215) at 0.1%, and the gamma irradiation with 10kGy, 15kGy, and 25kGy doses. The results showed that monopropylene glycol limited the microorganism growth and decreased the enzymatic activity at high concentration (up to 50%), at two temperatures (20 and 4 degrees C). Enzyme stored at 20 degrees C lost its activity by 80% after two months. This loss was attributed to the protease's effect. At this temperature, the protease's activities have been limited by the specific inhibitors. The gamma irradiations improve microbial safety of liquid enzyme. [less ▲]

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See detailBacillus lipopeptides: versatile weapons for plant disease biocontrol.
Ongena, MARC ULg; Jacques, Philippe

in Trends in Microbiology (2008), 16(3), 115-25

In the context of biocontrol of plant diseases, the three families of Bacillus lipopeptides - surfactins, iturins and fengycins were at first mostly studied for their antagonistic activity for a wide ... [more ▼]

In the context of biocontrol of plant diseases, the three families of Bacillus lipopeptides - surfactins, iturins and fengycins were at first mostly studied for their antagonistic activity for a wide range of potential phytopathogens, including bacteria, fungi and oomycetes. Recent investigations have shed light on the fact that these lipopeptides can also influence the ecological fitness of the producing strain in terms of root colonization (and thereby persistence in the rhizosphere) and also have a key role in the beneficial interaction of Bacillus species with plants by stimulating host defence mechanisms. The different structural traits and physico-chemical properties of these effective surface- and membrane-active amphiphilic biomolecules explain their involvement in most of the mechanisms developed by bacteria for the biocontrol of different plant pathogens. [less ▲]

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See detailSugar beet : a source of biofuel an chemicals.
Destain, Jacqueline ULg; Gigot, Cédric ULg; Fauconnier, Marie-Laure ULg et al

Poster (2007, June)

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See detailSugar beet leaves as source of green notes.
Gigot, Cédric ULg; Rabetafika, Holy-Nadia ULg; Fauconnier, Marie-Laure ULg et al

Poster (2007, June)

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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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