References of "Cawoy, Hélène"
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See detailPlant defense stimulation by natural isolates of Bacillus depends on efficient surfactin production
Cawoy, Hélène ULg; Mariutto, Martin; Henry, Guillaume et al

in Molecular Plant-Microbe Interactions [=MPMI] (2014), 27

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See detailTandem MS of -new- antibiotics from Bacillus guided by MALDI Mass Spectrometry Imaging
Debois, Delphine ULg; Jourdan, Emmanuel; Cawoy, Hélène ULg et al

Conference (2013, December 05)

Generally, an antibiotic is thought to have a role in antagonism simply because the producing strain is known to exhibit a potential for pathogen growth inhibition. Some genetic approaches such as PCR ... [more ▼]

Generally, an antibiotic is thought to have a role in antagonism simply because the producing strain is known to exhibit a potential for pathogen growth inhibition. Some genetic approaches such as PCR using specific primers or genome mining using known sequence data of close relatives are also used. Nevertheless, none of these methods allows stating for a link between a specific compound and the observed antagonism. Yet MALDI Mass Spectrometry Imaging (MSI) is a powerful tool to decipher the chemical messengers exchanged by two protagonists [1,2,3;]. Tandem mass spectrometry (MS/MS) may be also used, either on extracts [2,3] or directly on the microbial colonies [4]. The presentation will thus be focused on two examples of application of MALDI MSI combined to in situ tandem mass spectrometry. The first presented case will be the antagonism between soilborne strain Paenibacillus polymyxa Pp56 and the fungal phytopathogen Fusarium oxysporum. Using MALDI MSI, we were able to precisely localize each detected antibiotic, allowing discriminating which LI-F lipopeptides (fusaricidin) were really active against the pathogen progression. Besides, the use of in situ MS/MS allowed us to sequence the peptide moiety of several LI-F lipopeptides, showing that some of them are actually a mixture of several forms. The second example concerns the metabolites that are released by Bacillus amyloliquefaciens S499 cells following their inoculation on 7 days old tomato roots. We developed specific bioassays for time-course monitoring by MALDI MSI. First analyses revealed an efficient secretion of surfactin by Bacillus cells after 3 days when colonization as biofilm-structured populations is well established. Even if the composition of antibiotic mixture does not greatly evolve over time, after long incubation periods (32 or 35 days post inoculation), new series of compounds are detected in the tomato root -surrounding medium. Structural analysis based on exact mass measurements and MS/MS experiments, performed directly on the semi-solid agar medium, allowed us to identify these compounds as new variants of surfactins. [1] Barger, S., et al., Anton Leeuw Int J G, 2012, 102, 435-445. [2] Hoefler, B. C., et al,. Natl Acad Sci USA, 2012, 109, 13082-13087. [3] Moree, W. J., et al., Natl Acad Sci USA, 2012, 109, 13811-13816. [4] Debois, D., et al., J Am Soc Mass Spectrom. 2013, 24, 1202-1213 [less ▲]

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See detailMALDI-FTICR MS Imaging as a Powerful Tool to Identify Paenibacillus Antibiotics Involved in the Inhibition of Plant Pathogens
Debois, Delphine ULg; Ongena, Marc ULg; Cawoy, Hélène ULg et al

in Journal of the American Society for Mass Spectrometry (2013), 24(8), 1202-1213

Nowadays, microorganisms are more and more often used as biocontrol agents for crop protection against diseases. Among them, bacteria of Bacillus and Paenibacillus genders are already used as commercial ... [more ▼]

Nowadays, microorganisms are more and more often used as biocontrol agents for crop protection against diseases. Among them, bacteria of Bacillus and Paenibacillus genders are already used as commercial biocontrol agents. Their mode of action is supposed to be related to their production of antibiotics, such as cyclic lipopeptides, which exhibit great antimicrobial activities. We chose to work with a Paenibacillus polymyxa strain (Pp56) very resistant to various microorganisms. The bacteria were grown simultaneously with Fusarium oxysporum and we applied matrix-assisted laser desorption/ionization-Fourier transform ion cyclotron resonance (MALDI-FTICR) mass spectrometry to identify the antibiotics compounds present in the fungus growth inhibition area. We, therefore, identified fusaricidins A, B, and C and numerous members of the LI-F antibiotics family. MALDIFTICR mass spectrometry imaging was then used to follow the diffusion of lipopeptides involved in the inhibitory activity over time. We analyzed the molecular content of the inhibitory area at different Pp56 and Fusarium incubation durations and concluded that some lipopeptides such as fusaricidin B and a mixture of LI-F05b/06b/08a were mainly involved in the defense mechanism of Pp56. Our study confirms that MALDI imaging may be a powerful tool to quickly determine which molecular species is involved in an antagonism with another microorganism, avoiding time-consuming steps of extraction, purification, and activity tests, which are still commonly used in microbiology. [less ▲]

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See detailImportance of surfactin for plant resistance induction by Bacillus isolates
Cawoy, Hélène ULg; Mariutto, Martin; Jourdan, Emmanuel et al

Conference (2012, June 27)

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See detailModulation of the lipopeptide pattern secreted by Bacillus subtilis upon colonization of different plant roots
Ongena, Marc ULg; Cawoy, Hélène ULg; Smargiassi, Maïté et al

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2012), 78

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See detailImpact of rhizosphere factors on cyclic lipopeptide signature from the plant beneficial strain Bacillus amyloliquefaciens S499
Nihorimbere, Venant; Cawoy, Hélène ULg; Seyer, Alexandre et al

in FEMS Microbiology Ecology (2012), 79

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See detailThe role of surfactins in plant immunization by Bacilli
Cawoy, Hélène ULg; Henry, Guillaume ULg; Jourdan, Emmanuel ULg et al

Conference (2011, April)

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See detailBacillus-based biological control of plant diseases
Cawoy, Hélène ULg; Bettiol, Wagner; Fickers, Patrick et al

in Stoytcheva, Margarita (Ed.) Pesticides in the Modern World - Pesticides Use and Management (2011)

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See detailBeneficial effects of Bacillus subtilis on field-grown tomato in Burundi : reduction of local Fusarium disease and growth promotion.
Nihorimbere, V.; Ongena, Marc ULg; Cawoy, Hélène ULg et al

in African Journal of Microbiology Research [=AJMR] (2010), 4

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See detailBacillus-based biocontrol of Fusarium disease on tomato cultures in Burundi
Nihorimbere, Venant; Ongena, Marc ULg; Cawoy, Hélène ULg et al

Poster (2009, May 19)

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See detailPlant growth promotion of tomato under field conditions in Burundi
Cawoy, Hélène ULg; Nihorimbere, Venant; Kakana, Pascal et al

Poster (2009, April 02)

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