References of "Dommes, Jacques"
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See detailBeneficial use of lignosulfonates in in vitro plant cultures: stimulation of growth, of multiplication and of rooting
Docquier, Sarah; Kevers, Claire ULg; Lambe, Pascal et al

in Plant Cell, Tissue & Organ Culture (2007), 90(3), 285-291

Lignosulfonates (LIGNs), low-cost by-products from the paper industry, are already commercialized as fertilizers; they stimulate both vegetative and reproductive growths and fructification. LIGNs have ... [more ▼]

Lignosulfonates (LIGNs), low-cost by-products from the paper industry, are already commercialized as fertilizers; they stimulate both vegetative and reproductive growths and fructification. LIGNs have been tested in in vitro cultures and here too, they improve shoot growth and vigor, and rooting of various plant materials. This study aimed at to extend the in vitro application of LIGNs at different developmental stages in order to increase the productivity of systems generating vitroplants. The present results showed the beneficial effects of various LIGN applications on growth of a tropical orchid, Phalaenopsis, multiplication of Saint-paulia ionantha and rooting of poplar and Sequoiadendron sempervirens shoot cuttings. One of the most interesting observations was the stimulating effect of Ca-chelated LIGN on growth of Phalaenopsis and on rooting of Sequoiadendron. The significant and reproducible effects of LIGNs at several steps of micropropagation of different plant materials represent a potential tool improve quality without embarrassing side-effects. [less ▲]

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See detailConditioning Panax vietnamiensis cell mass production in bioreactors
Jacques, Philippe ULg; Kevers, Claire ULg; Gaspar, Th. et al

in Acta Botanica Gallica : Bulletin de la Société Botanique de France (2007), (154), 21-26

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See detailConditioning Panax vietnamensis cell mass production in bioreactors
Jacques, Philippe; Kevers, Claire ULg; Gaspar, Thomas et al

in Acta Botanica Gallica : Bulletin de la Société Botanique de France (2007), 154

The influence of lighting conditions, culture volume and four different auxins (indoleacetic acid (IAA), indolebutyric acid (IBA), 2,4-dichlorophenoxyacetic acid (2,4-D) or 3-(benzo[b]selenyl)acetic acid ... [more ▼]

The influence of lighting conditions, culture volume and four different auxins (indoleacetic acid (IAA), indolebutyric acid (IBA), 2,4-dichlorophenoxyacetic acid (2,4-D) or 3-(benzo[b]selenyl)acetic acid (BSAA)) on Panax vietnamensis cell growth was evaluated in flasks. The highest biomass productivity was observed under continuous light and in the presence of IBA (0.36 g DW l(-1) d(-1)) or BSAA (0.5 g DW l(-1) d(-1)). Cultures in bioreactors were performed with these two auxins. The final biomass concentration was 107 g FW l(-1) and 373 g FW l(-1) in the presence of IBA or BSAA, respectively. [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 detailOptimisation of extraction of phenolics and antioxidants from black currant leaves and buds and of stability during storage
Tabart, Jessica ULg; Kevers, Claire ULg; Sipel, Arnaud ULg et al

in Food Chemistry (2007), 105(3), 1268-1275

Health benefits of a diet rich in fruits and vegetables are attributed in part to their contents of phenolics and other antioxidant compounds. In this research, the extraction of phenolics and antioxidant ... [more ▼]

Health benefits of a diet rich in fruits and vegetables are attributed in part to their contents of phenolics and other antioxidant compounds. In this research, the extraction of phenolics and antioxidant compounds from black currant was optimised for different plant organs. The extraction solvent affected yield: aqueous acetone was better than methanol and acetate or glycine buffer. In aqueous buffer, maximum yields of total phenolics and antioxidant activities were obtained at pH 3. Extraction from lyophilised materials yielded extracts with higher phenolic contents and antioxidant activities. Stability of extracts made with acetate or glycine buffer was limited while the use of a mixture of acetone/acetic acid/water for extraction allowed a high phenolic content and antioxidant capacity in dry extract to be maintained for several months. This type of extract could be incorporated in functional food, beverage or dietary supplement. (c) 2007 Elsevier Ltd. All rights reserved. [less ▲]

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See detailAntioxidant capacity of black currant varies with organ, season, and cultivar
Tabart, Jessica; Kevers, Claire ULg; Pincemail, Joël ULg et al

in Journal of Agricultural and Food Chemistry (2006), 54(17), 6271-6276

Small berries such as black currant constitute one of the important sources of potential health-promoting phytochemicals because these fruits are rich sources of compounds with high antioxidant properties ... [more ▼]

Small berries such as black currant constitute one of the important sources of potential health-promoting phytochemicals because these fruits are rich sources of compounds with high antioxidant properties. In this work, antioxidant capacities of different parts (buds, leaves, fruits) of various black currant cultivars were compared throughout the growing season with the aim to prepare extracts with high antioxidant capacity. Buds (opened, at the end of March) and leaves (in June) had a higher content in phenolics and antioxidants than fully ripened berries (in July) and the best yield (per branch) was obtained with the leaves collected in June due to their higher biomass. The differences observed among the eight cultivars tested were small. Concerning flavonols, quercetin was dominant in all organs and cultivars, myricetin varied widely among the cultivars, and kampferol was very low. [less ▲]

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See detailA late blight resistant potato plant overexpresses a gene coding for alpha-galactosidase upon infection by Phytophthora infestans
Evers, Danièle; Ghislain, Marc; Hoffmann, Lucien et al

in Biologia Plantarum (2006), 50(2), 265-271

Late blight of potato, caused by Phytophthora infestans was studied by using a resistant clone of potato on one side and a susceptible clone on the other side. A gene coding putatively for an alpha ... [more ▼]

Late blight of potato, caused by Phytophthora infestans was studied by using a resistant clone of potato on one side and a susceptible clone on the other side. A gene coding putatively for an alpha-galactosidase has been isolated by mRNA reverse transcription polymerase chain reaction differential display and was shown to be differentially expressed between the resistant and the susceptible clone. alpha-Galactosidases catalyse the hydrolysis of alpha-1,6 linked alpha-galactose residues from oligosaccharides and it could be shown in the present work that raffinose content decreases at 30 h after infection by P. infestans in the resistant clone. [less ▲]

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See detailTwo PR-1 loci detected in the native cultivated potato Solanum phureja appear differentially expressed upon challenge by late blight
Evers, Danièle; Schweitzer, C.; Nicot, N. et al

in Physiological and Molecular Plant Pathology (2006), 67(3-5, SEP-OCT), 155-163

Plant pathogenesis-related proteins are toxic to invading pathogens. Among them, the Subfamily PR-1 represents low-molecular weight proteins of unknown biochemical function. Here, we describe the cloning ... [more ▼]

Plant pathogenesis-related proteins are toxic to invading pathogens. Among them, the Subfamily PR-1 represents low-molecular weight proteins of unknown biochemical function. Here, we describe the cloning and isolation of two PR-1 genes (PR-1b1 (GenBank accession no. SPH493450) and PR-1b2 (SPH493451)) that encode predicted basic proteins. We isolated them from Solanum phureja, a native Andean potato with horizontal resistance to late blight, caused by the oomycete Phytoplithora infestans. We demonstrate that the PR-1 genes belong to a small multigene family with an estimated copy number of 4-6 with one of them located oil chromosome IX as determined by genetic mapping. The expression of PR-1 genes was different in late blight resistant and Susceptible genotypes. Therefore, we propose that both PR-1 genes may play a role in horizontal late blight resistance of S. phureja. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailBacillus subtilis M4 decreases plant susceptibility towards fungal pathogens by increasing host resistance associated with differential gene expression
Ongena, MARC ULg; Duby, Franceline ULg; Jourdan, E. et al

in Applied Microbiology & Biotechnology (2005), 67(5), 692-698

Results presented in this paper describe the ability of Bacillus subtilis strain M4 to reduce disease incidence caused by Colletotrichum lagenarium and Pythium aphanidermatum on cucumber and tomato ... [more ▼]

Results presented in this paper describe the ability of Bacillus subtilis strain M4 to reduce disease incidence caused by Colletotrichum lagenarium and Pythium aphanidermatum on cucumber and tomato, respectively. Disease protection in both pathosystems was most probably due to induction of resistance in the host plant since experiments were designed in order to avoid any direct contact between the biocontrol agent and the pathogen. Pre-inoculation with strain M4 thus sensitised both plants to react more efficiently to subsequent pathogen infection. In cucumber, the use of endospores provided a disease control level similar to that obtained with vegetative cells. In contrast, a mixture of lipopeptides from the surfactin, iturin and fengycin families showed no resistance-inducing potential. Interestingly, treatment with strain M4 was also associated with significant changes in gene transcription in the host plant as revealed by cDNA-AFLP analyses. Several AFLP fragments corresponded to genes not expressed in control plants and specifically induced by the Bacillus treatment. In support to the macroscopic protective effect, this differential accumulation of mRNA also illustrates the plant reaction following perception of strain M4, and constitutes one of the very first examples of defence-associated modifications at the transcriptional level elicited by a non-pathogenic bacterium in a host plant. [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 detailOptimisation of Panax ginseng liquid cell cultures for biomass accumulation and ginsenoside production.
Kevers, Claire ULg; Bare, Gislain; Gaspar, Thomas ULg et al

in HVOSLEF-EIDE, Anne Kathrine; PREIL, Walter (Eds.) Liquid Culture Systems for in vitro Plant Propagation (2005)

Solid calli and derived liquid cell cultures were initiated from one-year-old roots of Panax ginseng CA Meyer. Half-strength Murashige and Skoog medium supplemented classically with an auxin and a ... [more ▼]

Solid calli and derived liquid cell cultures were initiated from one-year-old roots of Panax ginseng CA Meyer. Half-strength Murashige and Skoog medium supplemented classically with an auxin and a cytokinin did not appear favourable for biomass accumulation nor for a high ginsenoside content. Changes in the levels of mineral nutrients, sucrose and growth regulators were preliminary investigated here to improve growth and ginsenoside production in liquid cultures. The hypothesis that ginseng cells released growth inhibitors in the medium was not supported by the results obtained in experiments involving frequent transfers to fresh growth medium [less ▲]

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See detailStimulation of the lipoxygenase pathway is associated with systemic resistance induced in bean by a nonpathogenic Pseudomonas strain
Ongena, MARC ULg; Duby, Franceline ULg; Rossignol, Fanny et al

in Molecular Plant-Microbe Interactions (2004), 17(9), 1009-1018

Systemic defense reactions induced in bean by the nonpathogenic Pseudomonas putida BTP1 strain reduced disease caused by Botrytis cinerea. Phenylalanine ammonialyase activity and the level of endogenous ... [more ▼]

Systemic defense reactions induced in bean by the nonpathogenic Pseudomonas putida BTP1 strain reduced disease caused by Botrytis cinerea. Phenylalanine ammonialyase activity and the level of endogenous free sallicylic acid were compared in plant growth-promoting rhizobacteria-treated versus control plants, but no significant differences were detected. Furthermore, no enhanced fungitoxicity was detected in methanolic leaf extracts, suggesting that accumulation of bean phytoalexins was not part of the stimulated defense mechanisms. However, BTP1-inoculated plants showed increased levels of both linoleic and linolenic acids. On this basis, we further investigated whether the lipoxygenase pathway, leading to antifungal phytooxylipins, could have been stimulated. Two key enzymatic activities of this metabolic route, namely lipoxygenase and hydroperoxidelyase, were significantly stimulated during the first four days after challenging BTP1-treated plants with the pathogen. This was observed in parallel with a more rapid consumption of the respective substrates of these enzymes, as revealed by measurements of endogenous concentrations of linolenic acid and their hydroperoxide derivatives. Moreover, headspace-gas chromatography analyses showed significantly higher concentrations of the fungitoxic final product Z-3-hexenal in leaves from BTP1-inoculated beans as compared with control plants. Taken together, these results strongly suggest that the oxylipin pathway can be associated with enhanced disease resistance induced in bean plants by nonpathogenic rhizobacteria. [less ▲]

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See detailCloning and Expression Analysis of Cdnas Corresponding to Genes Activated in Cucumber Showing Systemic Acquired Resistance after Bth Treatment
Bovie, C.; Ongena, MARC ULg; Thonart, Philippe ULg et al

in BMC Plant Biology (2004), 4

BACKGROUND: Infection of plants by necrotizing pathogens can lead to the rapid and localized induction of a complex set of defense responses resulting in a restriction of pathogen growth and spread ... [more ▼]

BACKGROUND: Infection of plants by necrotizing pathogens can lead to the rapid and localized induction of a complex set of defense responses resulting in a restriction of pathogen growth and spread. Subsequently, an increase of plant resistance against a broad spectrum of pathogens is observed systemically. This plant immunity is known as Systemic Acquired Resistance. To identify components of the transduction pathway, we cloned and analysed the expression pattern of several mRNAs accumulating in cucumber plants after induction of Systemic Acquired Resistance. RESULTS: We tested on cucumber different compounds known to induce systemic acquired resistance. Among these, BTH (benzo(1,2,3)thiadiazole-7-carbothioic acid S-methyl ester) proved to be very effective. mRNA RT-PCR differential display was used to identify mRNA sequences induced 24 hours after the application of 10 microM BTH to cucumber plants. A cDNA library constructed from cucumber plants sprayed with 10 microM BTH was screened to get corresponding full length cDNAs. Among the identified cDNAs were those coding for a putative ras-related GTP-binding protein, a putative beta-1,4-N-Acetylglucosaminyltranferase III and a putative pathogenesis related protein. The time course of accumulation of the three corresponding mRNAs was analysed by northern blotting in plants treated by BTH or in plants infected by Colletotrichum lagenarium. CONCLUSIONS: The mRNA RT-PCR differential display technique allowed the identification of three genes possibly involved in Systemic Acquired Resistance in cucumber. Pathogenesis-related proteins are known to be involved in plant defence against pathogens. GTP-binding protein and N-acetylglucosaminyltranferase III have been reported to be components of signal transduction pathways in mammals and plants. [less ▲]

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See detailHyperhydricity of Prunus avium shoots cultured on gelrite: a controlled stress response
Franck, Thierry ULg; Kevers, Claire ULg; Gaspar, Thomas ULg et al

in Plant Physiology & Biochemistry (2004), 42(6), 519-527

Hyperhydricity is a physiological disorder frequently affecting shoots vegetatively propagated in vitro. Hyperhydric shoots are characterised by a translucent aspect due to a chlorophyll deficiency, a not ... [more ▼]

Hyperhydricity is a physiological disorder frequently affecting shoots vegetatively propagated in vitro. Hyperhydric shoots are characterised by a translucent aspect due to a chlorophyll deficiency, a not very developed cell wall and a high water content. Hyperhydricity of Prunus avium shoots was expressed in vitro in one multiplication cycle by replacing the gelling agent agar (normal shoots: NS) by gelrite (hyperhydric shoots: HS). P. avium shoots evolving towards the hyperhydric state produced higher amounts of ethylene, polyamines (PAs) and proline, which are substances considered as stress markers. A higher activity of glutathione peroxidase (GPX; EC 1.11.1.9), involved in organic hydroperoxide elimination, suggested an increased production of these compounds in HS. The unchanged free fatty acid composition indicated no HS membrane damages compared to NS. The ploidy level of HS nuclei was not affected, but the bigger size and the lower percentage of nuclei during the S phase suggested a slowing down of the cell cycle. The results argued for a stress response of the HS, but no signs of oxidative damages of lipid membrane and nucleus were observed. The discussion points out paradoxical results in a classical analysis of stress and suggests an alternative way of defense mechanisms in HS, involving homeostatic regulation and controlled degradation processes to maintain integrity and vital functions of the cell. (C) 2004 Elsevier SAS. All rights reserved. [less ▲]

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See detailHyperhydricity of micropropagated shoots: a typically stress-induced change of physiological state
Kevers, Claire ULg; Franck, Thierry ULg; Strasser, Reto et al

in Plant Cell, Tissue & Organ Culture (2004), 77(2), 181-191

Hyperhydricity of micropropagated shoots, formerly called vitrification, undoubtedly results from growth and culture conditions, subjectively reputated as stressing factors: wounding, infiltration of soft ... [more ▼]

Hyperhydricity of micropropagated shoots, formerly called vitrification, undoubtedly results from growth and culture conditions, subjectively reputated as stressing factors: wounding, infiltration of soft culture medium, generally of a high ionic strength, rich in nitrogen and in growth regulators in a special balance, in a humid and gaseous confined atmosphere. Stress is (objectively) defined as a disruption of homeostasis resulting from a constraint escaping the usual flexibility of metabolism. It induces another temporary (reversible) or definitive (irreversible) thermodynamic physiological state. The state-change concept developed by Strasser (1988) and Strasser and Tsimilli-Michael (2001) is applicable to the phenomenon of hyperhydricity. An appraisal of the redox capacities of hyperhydrated shoots together with a study of some enzymic activities that catalyse pentose phosphate and glycolytic pathways has indeed shown that such shoots have evolved towards a temporary state of lower differentiation or a juvenile state with a sufficient activity to survive and to defend themselves. [less ▲]

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See detailWood formation in in vitro propagated walnut shoots in relation with root formation and development
Kevers, Claire ULg; Bisbis, Badia; Crèvecoeur, Michèle et al

in Acta Botanica Gallica : Bulletin de la Société Botanique de France (2004), 151(1), 45-53

Lignification and xylem cell multiplication for wood formation were examined in in vitro propagated walnut shoot cuttings after transfer on an auxin-containing rooting medium for one week and subsequently ... [more ▼]

Lignification and xylem cell multiplication for wood formation were examined in in vitro propagated walnut shoot cuttings after transfer on an auxin-containing rooting medium for one week and subsequently during root development in vermiculite in the absence of growth regulators. Lignification in the shoot stems started immediately after the exogenous auxin treatment which implied changes in peroxidase activity and in free IAA levels. Sustained lignification required the completion of the following rooting phases. The lignin was exclusively located in xylem cells, the number of which increased with the number of developing roots. The mutual interactions between the aerial parts of the plants and their roots are discussed. [less ▲]

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