164 research outputs found
Science Dijon : une ambassadrice du savoir
No full textDépartement SPE Pôle IPMNational audienceChercheuse à l’Université de Bourgogne, Angélique Besson-Bard sera l’une des ambassadrices du programme “Pour les filles et la science”, destiné à promouvoir la science auprès des lycéennes
Science Dijon : une ambassadrice du savoir
No full textDépartement SPE Pôle IPMNational audienceChercheuse à l’Université de Bourgogne, Angélique Besson-Bard sera l’une des ambassadrices du programme “Pour les filles et la science”, destiné à promouvoir la science auprès des lycéennes
Effets de l’apo-pyoverdine de <em>Pseudomonas fluorescens</em> C7R12 sur l’homéostasie du fer et les réactions de défense d’<em>Arabidopsis thaliana</em>
No full textSPE IPM UBNational audienceLe GDR est un réseau de ressources et de compétences en microbiologie clinique et environnementale sur le thème principal des bactéries Pseudomonas aeruginosa (pathogène de l’homme) et fluorescents du sol (P. putida et P. fluorescens)</em
BABA-induced resistance in Arabidopsis thaliana: Links with iron homeostasis
No full textéquipe SPE (UB) IPMNational audienc
NO contributes to cadmium toxicity in Arabidopsis thaliana by mediating an iron deprivation response
No full textInternational audienceSeveral studies have revealed that nitric oxide (NO), an endogenous mediator in diverse physiological processes, is produced in plants exposed to the toxic metal cadmium (Cd). It was first shown that exogenously applied NO protects plant tissues against the oxidative damages triggered by Cd, suggesting a putative role for NO in counteracting the deleterious effects of Cd. More recently, our team as well as other laboratories challenged this view and demonstrated that endogenously produced NO promotes the metal-induced reduction of root growth. We investigated more thoroughly the role of NO in mediating Cd effects in roots. We have shown that in Arabidopsis thaliana, the Cd-mediated NO production is sensitive to mammalian NO synthase inhibitors and occurs downstream of IRT1, a major iron transporter also involved in the uptake of Cd. Our data support a model in which this production might be related to the iron deprivation caused by Cd. Accordingly, we found that NO up-regulates the expression of genes encoding proteins related to iron acquisition, including IRT1. This process might explain the ability of NO to amplify Cd uptake and, consequently, the toxic effects of the metal
Identification et analyse du rôle de protéines S‐nitrosylées lors de la modulation de la réponse immunitaire <em>d’Arabidopsis thaliana</em> par l’apo-pyoverdine produite par la souche bactérienne bénéfique <em>Pseudomonas fluorescens C7R12</em>
No full textProd 2019-70h SPE IPM UB DOCTNational audienceDes travaux de l’UMR Agroécologie montrent que la réponse immunitaire des plantes est corrélée à leur nutrition en fer et est modulable par la pyoverdine, un sidérophore produit par la souche bactérienne bénéfique Pseudomonas fluorescens C7R12. Le traitement d’Arabidopsis thaliana exposée à une carence en fer par la pyoverdine dépourvue de fer (apo-pyo) restaure en effet la croissance de la plante aux dépens de son immunité. Nous avons émis l’hypothèse que le monoxyde d’azote (NO), une molécule signalétique ubiquitaire, est un acteur de la modulation de la réponse immunitaire des plantes exposées à l’apo-pyo et à sa souche productrice. Afin d’étayer cette hypothèse, trois axes seront développés : - Identification de protéines S‐nitrosylées en réponse à l’apo-pyo et à P. fluorescens C7R12. La S-nitrosylation est un mécanisme majeur de modification posttraductionnelle de protéines impliquant le NO et ciblant les résidus cystéines (Cys). - Analyse du rôle du NO sur la fonction/structure des protéines cibles. Il s’agira d’analyser in vitro l’incidence du NO sur l’activité et la structure des protéines d’intérêt puis d’identifier les résidus Cys régulés par le NO. - Etude de l’incidence de la S-nitrosylation des protéines d’intérêt in planta. Des plantes d’A. thaliana invalidées dans l’expression des protéines d’intérêt ou exprimant celles-ci sous une forme non nitrosylable seront générées puis leur interaction avec des micro-organismes pathogènes ou bénéfiques sera étudiée
Real-time electrochemical detection of extracellular nitric oxide in tobacco cells exposed to cryptogein, an elicitor of defence responses
No full textInternational audienceIt was previously reported that cryptogein, an elicitor of defence responses, induces an intracellular production of nitric oxide (NO) in tobacco. Here, the possibility was explored that cryptogein might also trigger an increase of NO extracellular content through two distinct approaches, an indirect method using the NO probe 4,5-diaminofluorescein (DAF-2) and an electrochemical method involving a chemically modified microelectrode probing free NO in biological media. While the chemical nature of DAF-2-reactive compound(s) is still uncertain, the electrochemical modified microelectrodes provide real-time evidence that cryptogein induces an increase of extracellular NO. Direct measurement of free extracellular NO might offer important new insights into its role in plants challenged by biotic stresses
Electrochemical detection of nitric oxide in plant cell suspensions
No full textSPE IPM UBInternational audienceNitric oxide is a hydrophobic radical acting as a physiological mediator in plants. Because of its unique properties, the detection of NO in plant tissues and cell suspensions remains a challenge. For this purpose, several techniques are used, each having certain advantages and limitations such as interferences with other species, questionable sensitivity, and/or selectivity or ex situ measurement. Here we describe a very attractive approach for tracking NO in plant cell suspensions using a NO-sensitive homemade platinum/iridium-based electrochemical microsensor. This method constitutes the absolute real-time proof of the production of free NO in physiological conditions
The impact of the plant-associated siderophore ornicorrugatin on <em>Arabidopsis thaliana</em>
No full textProd 2018-89 SPE EA BIOME IPM INRA UBInternational audienceMost microorganisms produce siderophores when they are faced with iron-limiting conditions. Fluorescent pseudomonads produce a yellow-green, fluorescent siderophore, called pyoverdine. Besides pyoverdine, sev-eral other secondary siderophores, which have a relatively lower affinity for iron, have been identified in Pseu-domonas spp. Examples are pyochelin, pseudomonine and thioquinolobactin (Cornelis and Matthijs 2002). An atypical set of secondary siderophores, due to their lipopeptidic nature, are the siderophores corrugatin (Risse et al., 1998), ornicorrugatin (Matthijs et al., 2008) and histicorrugatin (Matthijs et al., 2016). These siderophores consist out of an 8 amino acid long peptide which is linked to octanoic acid, an eight-carbon saturated fatty acid. They differ from each other by having 1 or 2 amino acid changes in the peptide chain. The phylogenetic distribution of Pseudomonas strains producing one of these 3 siderophores throughout the Pseudomonas genus, represented by more than 700 strains, was studied by means of PCRs with primers spe-cific for the receptor and/or the biosynthetic genes of histicorrugatin, ornicorrugatin and corrugatin, and by means of mass analysis to identify the siderophore produced. In addition, sequenced genomes were screened in silico for biosynthetic or uptake genes of histicorrugatin, ornicorrugatin or corrugatin. Well-defined subclusters of Pseudomonas strains producing one of these siderophores have been identified in the P. fluorescens group. Remarkably, when looking at the biological origin of the producing strains it was found that the ability to produce histicorrugatin, ornicorrugatin or corrugatin is almost exclusively found in Pseudomonas strains isolated from plants. To gain insight in the role of histicorrugatin, ornicorrugatin or corrugatin in the interaction of Pseudomonas with the plant, the effect of one of these siderophores is being investigated. As a model system Pseudomonas fluo-rescens C7R12 and Arabidopsis thaliana have been chosen. C7R12 produces pyoverdine (PYOC7R12) and or-nicorrugatin. The impact of PYOC7R12 on Arabidopsis thaliana plants facing iron deficiency, has already been studied (Trapet et al., 2016). Under this condition, apo-PYOC7R12 modulated the expression of around 2000 genes, it positively regulated the expression of genes related to development and iron acquisition/redistribution while it repressed the expression of defense-related genes (Trapet et al., 2016). This mechanism being dependent on the expres-sion of the iron uptake-related genes IRT1 and FRO2 (Trapet et al., 2016). The impact of ornicorrugatin is now being studied using purified ornicorrugatin and ornicorrugatin-negative mutants. REFERENCES Cornelis P. and Matthijs S. (2002) Diversity of siderophore-mediated iron uptake systems in fluorescent pseudomonads: not only pyover-dines. Environ Microbiol 4: 787-798. Risse D., Beiderbeck H., Taraz K., Budzikiewicz H., Gustine D. (1998) Corrugatin, a lipopeptide from Pseudomonas corrugata. Z Naturforsch C 53: 295-304. Matthijs S., Brandt N., Ongena M., Achouak W., Meyer J.-M., Budzikiewicz H. (2016) Pyoverdine and histicorrugatin-mediated iron acquisi-tion in Pseudomonas thivervalensis Biometals 29: 467-85. Matthijs S., Budzikiewicz H., Schäfer M., Wathelet B., Cornelis P. (2008) Ornicorrugatin, a new siderophore from Pseudomonas fluorescens AF76. Z Naturforsch 63c, 8-12. Trapet P., Avoscan L., Klinguer A., Pateyron S ., Citerne S., Chervin C., Mazurier S., Lemanceau P., Wendehenne D. and Besson-Bard A. (2016) The Pseudomonas fluorescens siderophore pyoverdine weakens Arabidopsis thaliana defense in favour of growth in iron-deficient conditions. Plant Physiol. 171: 675-693
New insights about the role of the chaperon-like protein Cdc48, a target for nitric oxide in plant immunity
No full textSPE Pôle IPMInternational audienc
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