0000000000534472
AUTHOR
Christine Arnould
Symbiosis-related plant genes modulate molecular responses in an arbuscular mycorrhizal fungus during early root interactions
International audience
Localisation de l’expression de gènes fongiques lors des différentes étapes de la mycorhization : développement de la méthode de RT-PCR in situ
National audience
Mobilité du sel dans des modèles fromagers
National audience; Reducing salt content without affecting acceptability is a main challenge of food industries. One way could be to increase the mobility of sodium ions in food matrix and their release during consumption. This study consists in a multimodal approach to understand the effect of changes in composition of model cheeses on the mobility of salt (NaCl). Six flavoured model cheeses have been formulated (three lipid/protein ratios, two NaCl contents) and their microstructures were characterised by confocal laser scanning microscopy. At molecular level, sodium mobility in model cheeses was analysed by 23Na Nuclear Magnetic Resonance (NMR) spectroscopy. At macroscopic level, sodium …
Over-expression of the epidermis-specific HD-ZIP IV transcription factor OCL1 in maize identifies target genes involved in lipid metabolism and cuticle biosynthesis.
International audience
Deciphering the molecular dialogue between arbuscular mycorrhizal partners during early root interactions
International audience
Sugar exchanges in arbuscular mycorrhiza: RiMST5 and RiMST6, two novel Rhizophagus irregularis monosaccharide transporters, are involved in both sugar uptake from the soil and from the plant partner
SPE IPM INRA UB CT1; International audience; Arbuscular mycorrhizal (AM) fungi are associated with about 80% of land plants. AM fungi provide inorganic nutrients to plants and in return up to 20% of the plant-fixed CO2 is transferred to the fungal symbionts. Since AM fungi are obligate biotrophs, unraveling how sugars are provided to the fungus partner is a key for understanding the functioning of the symbiosis. In this study, we identified two new monosaccharide transporters from Rhizophagus irregularis (RiMST5 and RiMST6) that we characterized as functional high affinity monosaccharide transporters. RiMST6 was characterized as a glucose specific, high affinity H(+) co-transporter. We prov…
A clearing protocol for pigmented roots : make symbiotic micro-organisms visible in 3D
Structure and composition of model cheeses influence sodium NMR mobility, kinetics of sodium release and sodium partition coefficients
International audience; The mobility and release of sodium ions were assessed in model cheeses with three different lipid/protein ratios, with or without added NaCl. The rheological properties of the cheeses were analysed using uniaxial compression tests. Microstructure was characterised by confocal laser scanning microscopy. (23)Na nuclear magnetic resonance (NMR) spectroscopy was used to study the molecular mobility of sodium ions in model cheeses through measurements of the relaxation and creation times. Greater mobility was observed in cheeses containing a lower protein content and with added NaCl. The kinetics of sodium release from the cheese to an aqueous phase was correlated with th…
La microdissection laser: une technique d'analyse du profil d'expression génique et protéique des types cellulaires spécifiques de la symbiose mycorhizienne à arbuscules
Cryo-méthodes appliquées à l’étude des interactions entre plantes et Pseudomonas Fluorescents en relation avec le fer dans la rhizosphère
SPEBAPEAIPMBIOmE; Cryo-méthodes appliquées à l’étude des interactions entre plantes et [i]Pseudomonas Fluorescents[/i] en relation avec le fer dans la rhizosphère. 7. Journées Scientifiques et Techniques du Réseau des Microscopistes de l'INRA (RμI)
Nutrition et protection de la vigne par la symbiose mycorhizienne à arbuscule
National audience; La vigne, comme la majorité des espèces de plante d’intérêt agronomique, forme une symbiosemutualiste avec les Champignons Mycorhiziens à Arbuscules (CMA). En contrepartie deproduits issus de la photosynthèse, les CMA soutiennent leur(s) plante(s) hôte(s) dansl’acquisition de nutriments et la lutte contre leur(s) pathogène(s). En tant que biofertilisants, cessymbiontes obligatoires représentent une alternative de choix à l’égard des pratiques agricolesconventionnelles pour le développement d’une agriculture, et notamment d’une viticulturedurable. Les échanges entre les deux partenaires sont permis par la mise en place de structuresfongiques spécialisées appelées arbuscule…
Identification of sugar transporters in arbuscular mycorrhiza, from basic to applied science
Our study focuses on sugar transporters from both plant and fungal partners at the symbiotic interface to better understand biotrophic exchange systems. Thereby, a collection of putative contigs and ESTs of hexose transporters from Medicago truncatula and Fragaria x ananassa will be processed. The full length sequences will be cloned for functional complementation and uptake experiments in transport deficient yeast mutants. This work also investigates the influence of different mycorrhizal fungi on (1) the expression level of sugar transporters and (2) the economically relevant part of F. x ananassa by analyzing its impact on the plant and the fruit. To this aim, combination of phenological…
La microscopie électronique à balayage au sein d’une Plate-Forme : applications «trans-règnes» en synergie avec d’autres techniques d’imagerie
Role of a transcription factor, GintSTE, from Glomus intraradices in the establishment of arbuscular mycorrhizal
International audience
5èmes Journées Scientifiques et Techniques du Réseau des Microscopistes INRA. « Imagerie cellulaire en science du vivant : Cryo-microscopies, Dynamiques in vivo et Interactions moléculaires »
National audience; L’imagerie cellulaire, dans le domaine des sciences du vivant, est essentielle à la compréhension des phénomènes cellulaires subcellulaires régulant le fonctionnement des cellules et tissus. En microscopie électronique, la mise en oeuvre de cryo-méthodes permet de préserver l’intégrité moléculaire et spatiale des protéines et lipides intracellulaires ou membranaires (de faible poids moléculaire, présentes en faible quantité ou très labiles) dont la localisation in situ est recherchée afin de caractériser leur organisation, participer à la détermination de leur fonction au sein de la cellule et d’analyser leur distribution. Ces techniques, en pleine évolution, seront abord…
Localisation et visualisation de transcrits fongiques in situ: Une méthode originale qui combine biologie moléculaire et microscopie confocale
National audience; Les Gloméromycètes, formant la symbiose mycorhizienne à arbuscules, sont des champignons biotrophes obligatoires qui sont intimement associés aux tissus végétaux qu’ils colonisent. Les techniques utilisées pour suivre l’expression des gènes fongiques dans les racines mycorhizées ne permettent pas de définir le profil spatio-temporel de leur activité. Afin de tracer l’activité transcriptionnelle fongique dans les racines mycorhizées, une méthode innovante, basée sur la RT-PCR in situ, a donc été développée. Cette technique permet de localiser, en microscopie optique confocale à balayage laser, des transcrits fongiques, à l’aide d’amorces spécifiques marquées par un fluoroc…
Analyse des interactions trophiques entre les plantes et les microorganismes par des biosenseurs de sucres
Expression of Sorghum bicolor ammonium transporters upon colonization with arbuscular mycorrhizal fungi
Arbuscular mycorrhizal fungi (AMF) are important plant symbionts, trading mineral nutrients beyond the reach of roots, in particular ammonium, in exchange to their host’s photosynthetic products. Sorghum bicolor is one of the world's leading cereal crops, providing food, fibre and fuel across a range of environments and production systems. It has a particular ability to be productive even under strongly adverse conditions, tolerating much more severe drought than most other grain crops. As its genome has recently been sequenced, we have characterized all eight members of the ammonium transporter (AMT) family and studied their expression in different tissues of field-grown plants. While most…
Adhesion of salivary mucins (MUC5B) to human buccal cells as affected by a taste solution
National audience
Structure-function analysis of peroxisomal ATP-binding cassette transporters using chimeric dimers
Background: Peroxisomal ABC transporters are predicted to function as homodimers in mammals. [br/] Results: ABCD1 interacts with ABCD2. Chimeric proteins mimicking full-length dimers represent novel tools for functional study. Artificial homodimers and heterodimers are functional. [br/] Conclusion: Interchangeability between ABCD1 and ABCD2 is confirmed, but PUFA transport depends on ABCD2. [br/] Significance: For the first time, heterodimers in mammals are proven to be functional.[br/] ABCD1 and ABCD2 are two closely related ATP-binding cassette half-transporters predicted to homodimerize and form peroxisomal importers for fatty acyl-CoAs. Available evidence has shown that ABCD1 and ABCD2 …
Symbiose ou pathogenèse? Quels peuvent être les mécanismes moléculaires déterminants?
National audience
Erratum to “Hydrolytic enzyme activity of Paenibacillus sp. strain B2 and effects of the antagonistic bacterium on cell integrity of two soil-borne pathogenic fungi”
Ce texte contient des corrections apportées à l'article " Hydrolytic enzyme activity of Paenibacillus sp. strain B2 and effects of the antagonistic bacterium on cell integrity of two soil-borne pathogenic fungi" sorti dans le numéro 15 du journal "Applied Soil Ecology" sorti en 2000.
Symbiosis-related plant genes modulate molecular responses in an arbuscular mycorrhizal fungus during early root interactions: molecular in vitro and in situ approaches
National audience
Symbiosis-related plant genes modulate molecular responses in an arbuscular mycorrhizal fungus during early root interactions.
To gain further insight into the role of the plant genome in arbuscular mycorrhiza (AM) establishment, we investigated whether symbiosis-related plant genes affect fungal gene expression in germinating spores and at the appressoria stage of root interactions. Glomus intraradices genes were identified in expressed sequence tag libraries of mycorrhizal Medicago truncatula roots by in silico expression analyses. Transcripts of a subset of genes, with predicted functions in transcription, protein synthesis, primary or secondary metabolism, or of unknown function, were monitored in spores and germinating spores and during interactions with roots of wild-type or mycorrhiza-defective (Myc–) mutan…
An STE12 gene identified in the mycorrhizal fungus Glomus intraradices restores infectivity of a hemibiotrophic plant pathogen
International audience; * • Mechanisms of root penetration by arbuscular mycorrhizal (AM) fungi are unknown and investigations are hampered by the lack of transformation systems for these unculturable obligate biotrophs. Early steps of host infection by hemibiotrophic fungal phytopathogens, sharing common features with those of AM fungal colonization, depend on the transcription factor STE12. * • Using degenerated primers and rapid amplification of cDNA ends, we isolated the full-length cDNA of an STE12-like gene, GintSTE, from Glomus intraradices and profiled GintSTE expression by real-time and in situ RT-PCR. GintSTE activity and function were investigated by heterologous complementation …
Ultrastructural and cell wall modifications during infection of Eucalyptus viminalis roots by a pathogenic Fusarium oxysporum strain
Fusarium species are soil-borne fungal pathogens that produce a variety of disease symptoms when attacking crop plants. The mode of root colonization of Eucalyptus viminalis seedlings by a pathogenic F. oxyporum strain (Foeu1) at the ultrastructural level and changes in cell wall pectin during host pathogen interactions are described. Root systems of E. viminalis plants were inoculated with F. oxysporum in an in vitro model system. Hyphae of F. oxysporum adhered to the outer epidermal cell walls through fibrillar material, and after penetration they spread into the internal tissues. They developed intercellularly and intracellularly in the root cortex and invaded vascular tissues. Papillae …
Signposting compatibility events initiating the mycorrhizal route
International audience
Approche tridimensionnelle de la répartition spatiale du champignon mycorhizien à arbuscule sur racines transparisées
L’imagerie tridimensionnelle d’échantillons volumineux est limitée par les phénomènes de réfraction et d’absorption de la lumière par les composants tissulaires (lipides, pigments...). Afin de limiter ses phénomènes et permettre l’acquisition d’image sur toute l’épaisseur d’une racine mycorhizée, il est nécessaire de rendre transparent les échantillons. Cela est possible en dépigmentant et en homogénéisant les différents indices de réfraction au sein du tissu, via des traitements chimiques. Cette technique, appelée transparisation, permet une analyse tridimensionnelle sur échantillon entier des structures d’intérêt marquées par fluorescence. Une vingtaine de techniques différentes de clarif…
Cell interactions between a nonpathogenic Fusarium oxysporum strain and root tissues of Eucalyptus viminalis
Nonpathogenic isolates of Fusarium oxysporum can be successful antagonists of pathogenic forms of the same fungal species that commonly attacks crop plants. The characteristics that distinguish nonpathogenic from pathogenic forms are not well understood. In this study, the mode of root colonization of Eucalyptus viminalis seedlings by a nonpathogenic F. oxysporum strain is described at the ultrastructural level. Root systems of E. viminalis plants were inoculated with nonpathogenic F. oxysporum strain Fo47 in an in vitro model system. Changes in the occurrence of nonesterified and methyl-esterified pectins in colonized E. viminalis roots were evaluated by in situ immunolabeling using two mo…
Sugar exchanges in arbuscular mycorrhiza : Characterization and role of two new monosaccharide transporters from the model fungus Rhizophagus irregularis
How does composition of model cheeses affect sodium and aroma release?
International audience
Phylogeny and gene expression analyses of ammonium transporters (AMT) induced by mycorrhization and nodule symbiosis among Papilionoideae subfamily
The study of plant-microbe associations through nutrient exchanges has significantly improved our understanding of plant microbiome. Legume plants establish mutualistic associations with both rhizobial bacteria and arbuscular mycorrhizal fungi [1]. These symbioses improve mineral plant nutrition and increase plant resistance against biotic and abiotic stresses. Plant-microbe associations provide key features for the current agricultural and environmental challenges [2]. Translocation mechanisms of nitrogen from the fungal and rhizobial symbiotic interfaces to the plant are not well-defined yet. In Poaceae plant, inductions of specific ammonium transporters (AMT) genes [3, 4] and nitrogen/pe…
Fungal genes related to calcium homeostasis and signalling are upregulated in symbiotic arbuscular mycorrhiza interactions
Fluctuations in intracellular calcium levels generate signalling events and regulate different cellular processes. Whilst the implication of Ca2+ in plant responses during arbuscular mycorrhiza (AM) interactions is well documented, nothing is known about the regulation or role of this secondary messenger in the fungal symbiont. The spatio-temporal expression pattern of putatively Ca2+-related genes of Glomus intraradices BEG141 encoding five proteins involved in membrane transport and one nuclear protein kinase, was investigated during the AM symbiosis. Expression profiles related to successful colonization of host roots were observed in interactions of G. intraradices with roots of wild-ty…
Rôle du facteur de transcription fongique GintSTE dans l’établissement de la symbiose mycorhizienne à arbuscules
National audience
Identification of sugar transporters in arbuscular mycorrhiza
Our study focuses on sugar transporters from both plant and fungal partners at the symbiotic interface to better understand biotrophic exchange systems. Thereby, a collection of putative contigs and ESTs of hexose transporters from Medicago truncatula and Fragaria x ananassa will be processed. The full length sequences will be cloned for functional complementation and uptake experiments in transport deficient yeast mutants. This work also investigates the influence of different mycorrhizal fungi on (1) the expression level of sugar transporters and (2) the economically relevant part of F. x ananassa by analyzing its impact on the plant and the fruit. To this aim, combination of phenological…
Proteomic analysis of sub-retinal deposits in age-related macular degeneration
National audience
The use of genomic repeated sequences to characterize arbuscular mycorrhizal fungi
International audience
La microdissection laser: une technique d’analyse du profil d’expression génique et protéique des types cellulaires spécifiques de la symbiose mycorhizienne à arbuscules
Spatial monitoring of gene activity in extraradical and intraradical developmental stages of arbuscular mycorrhizal fungi by direct fluorescent in situ RT-PCR
International audience; Gene expression profiling based on tissue extracts gives only limited information about genes associated with complex developmental processes such as those implicated in fungal interactions with plant roots during arbuscular mycorrhiza development and function. To overcome this drawback, a direct fluorescent in situ RT-PCR methodology was developed for spatial mapping of gene expression in different presymbiotic and symbiotic structures of an arbuscular mycorrhizal fungus. Transcript detection was optimized by targeting the LSU rRNA gene of Glomus intraradices and monitoring expression of a stearoyl-CoA-desaturase gene that is consistently expressed at high levels in…
Pea genes modulate symbiosis-associated fungal and plant molecular responses during late stages of the arbuscular mycorrhizal symbiosis
International audience
Hydrolytic enzyme activity of Paenibacillus sp. strain B2 and effects of the antagonistic bacterium on cell integrity of two soil-borne pathogenic fungi
Paenibacillus sp. strain B2, isolated from the mycorrhizosphere of Sorghum bicolor and having an antagonistic activity towards soil-borne fungal pathogens, possessed extracellular cellulolytic, proteolytic, chitinolytic and pectinolytic enzyme activities. The eventual role of these lytic enzymes in cellular interactions between Paenibacillus sp. strain B2 and Phytophthora parasitica and Fusariumoxysporum was investigated by electron microscopy and molecular cytology. Electron microscopic observations showed that the presence of Paenibacillus sp. strain B2 resulted in disorganisation of cell walls and/or cell contents of P. parasitica and F. oxysporum. However, when P. parasitica was treated…
Structure and composition of flavoured model cheeses impact on sodium and aroma release
Présentation d'un diaporama ; https://colloque4.inra.fr/biopolymeres2010; Health authorities have called for a reduction of salt quantity in various foodstuffs. Cheese is one of the most targeted products because of its high sodium content. In order to understand how to reduce salt in cheeses without modifying salty perception, the interactions between cheese structure and in-mouth sodium release have to be studied. In this way, model cheeses have been selected due to their great variability of formulation. The current study was conducted to determine how the release of sodium ions and aroma compounds could be modified by structure and composition of model cheeses (lipid/protein ratio, sodi…
Preservation of viability and anti-Listeria activity of lactic acid bacteria, Lactococcus lactis and Lactobacillus paracasei, entrapped in gelling matrices of alginate or alginate/caseinate
In order to control undesirable microorganisms growth in foods, the performance of alginate and alginate-caseinate (an aqueous two-phase system) matrices entrapping lactic acid bacteria (LAB) (Lactobacillus paracasei LAB1 and Lactococcus lactis LAB3) was investigated. Polymeric matrices were initially loaded with Lcells at similar to 10(8-10) or similar to 10(4-6) CFU mL(-1), and were monitored, in liquid and gelled form (beads), for 12 days at 30 degrees C. In the liquid form, maximum cell density (similar to 10(9) CFU mL(-1)) was reached after 24 h whatever the matrix. Then, the Lpopulation decreased but remained higher in alginate-caseinate matrices: 10(7) and 10(6) CFU mL(-1) of LAB3 ce…
Corrigendum to “Spatial monitoring of gene activity in extraradical and intraradical developmental stages of arbuscular mycorrhizal fungi by direct fluorescent in situ RT-PCR” [Fungal Genet. Biol. 45 (2008) 1155–1165]
Mycorhization en viticulture : état des lieux et étude de l’intérêt au vignoble
SPEIPMUBINRA; Mycorhization en viticulture : état des lieux et étude de l’intérêt au vignoble. 13. Journée Technique du CIVB (Conseil Interprofessionnel du Vin de Bordeaux)
Dual Cherenkov Radiation-Induced Near-Infrared Luminescence Imaging and Photodynamic Therapy toward Tumor Resection
International audience; Cherenkov radiation (CR), the blue light seen in nuclear reactors, is emitted by some radiopharmaceuticals. This study showed that (1) a portion of CR could be transferred in the region of the optical spectrum, where biological tissues are most transparent: as a result, upon radiance amplification in the near-infrared window, the detection of light could occur twice deeper in tissues than during classical Cherenkov luminescence imaging and (2) Cherenkov-photodynamic therapy (CR-PDT) on cells could be achieved under conditions mimicking unlimited depth using the CR-embarked light source, which is unlike standard PDT, where light penetration depth is limited in biologi…