A5019533378- Legume Nitrogen Fixing Symbiosis
- Plant nutrient uptake and metabolism
- Nematode management and characterization studies
- Plant Micronutrient Interactions and Effects
- Agronomic Practices and Intercropping Systems
- Cassava research and cyanide
- Plant-Microbe Interactions and Immunity
- Plant Pathogenic Bacteria Studies
- Plant Stress Responses and Tolerance
- Soybean genetics and cultivation
- Plant responses to water stress
- Amino Acid Enzymes and Metabolism
- Plant Pathogens and Fungal Diseases
- Microbial Community Ecology and Physiology
- Plant Molecular Biology Research
- Microbial Metabolites in Food Biotechnology
- Metalloenzymes and iron-sulfur proteins
- Ammonia Synthesis and Nitrogen Reduction
Université Côte d'Azur
2000-2024
Centre National de la Recherche Scientifique
2012-2024
Institut Sophia Agrobiotech
2012-2024
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
2019-2024
Observatoire de la Côte d’Azur
2018-2019
Laboratoire des Interactions Plantes Micro-Organismes
2010
Dartmouth College
2000
Abstract Nitric oxide (NO) is a signaling and defense molecule of major importance in living organisms. In the model legume Medicago truncatula, NO production has been detected nitrogen fixation zone nodule, but systems responsible for its synthesis are yet unknown role symbiosis far from being elucidated. this work, using pharmacological genetic approaches, we explored enzymatic source M. truncatula-Sinorhizobium meliloti nodules under normoxic hypoxic conditions. When transferred normoxia...
A bacterial membrane protein, BacA, protects Sinorhizobium meliloti against the antimicrobial activity of host peptides, enabling peptides to induce persistence rather than death.
Nitric oxide (NO) is a signalling and defence molecule involved in diverse plant developmental processes, as well the response to pathogens. NO has also been detected at different steps of symbiosis between legumes rhizobia. required for an optimal establishment Medicago truncatula-Sinorhizobium meliloti symbiotic interaction, but little known about role mature nodules. Here, we investigate late symbiosis. Genetic pharmacological approaches were conducted modulate level inside root nodules,...
ABSTRACT The role of glycine betaine and choline in osmoprotection various Rhizobium , Sinorhizobium Mesorhizobium Agrobacterium Bradyrhizobium reference strains which display a large variation salt tolerance was investigated. When externally provided, both compounds enhanced the growth tropici meliloti fredii galegae tumefaciens loti huakuii demonstrating their utilization as osmoprotectants. However, were inefficient for most salt-sensitive strains, such leguminosarum (all biovars),...
Glycine betaine is a potent osmoprotectant accumulated by Sinorhizobium meliloti to cope with osmotic stress. The biosynthesis of glycine from choline encoded an operon four genes, betICBA , as determined sequence and mutant analysis. betI betC genes are separated intergenic region containing 130-bp mosaic element that also present between the betB betA genes. In addition encoding presumed regulatory protein ( ), aldehyde dehydrogenase ) enzymes found in Escherichia coli new gene was...
Legumes form a symbiotic interaction with Rhizobiaceae bacteria, which differentiate into nitrogen-fixing bacteroids within nodules. Here, we investigated in vivo the pH of peribacteroid space (PBS) surrounding bacteroid and variation throughout symbiosis. In confocal microscopy investigations, using acidotropic probes, demonstrated acidic state PBS. planta analysis nodule senescence induced by distinct biological processes drastically increased PBS N2 -fixing zone (zone III). Therefore,...
• Legumes form a symbiotic interaction with bacteria of the Rhizobiaceae family to produce nitrogen-fixing root nodules under nitrogen-limiting conditions. We examined importance glutathione (GSH) and homoglutathione (hGSH) during nitrogen fixation process. Spatial patterns expression genes involved in biosynthesis both thiols were studied using promoter-GUS fusion analysis. Genetic approaches nodule zone-specific cysteine rich (NCR001) promoter employed determine (h)GSH biological (BNF)....
Summary The symbiotic interaction between legumes and R hizobiaceae leads to the formation of new root organs called nodules. Within nodule, differentiate into nitrogen‐fixing bacteroids. However, this is time‐limited as a result initiation senescence process, leading complete degradation bacteroids host plant cells. increase in proteolytic activity one key features process. In study, we analysed involvement two different classes cysteine proteinases, M t CP 6 VPE , process edicago...
As a first step towards the elucidation of molecular mechanisms responsible for utilization choline and glycine betaine (betaine) either as carbon nitrogen sources or osmoprotectants in Sinorhizobium meliloti, we selected Tn5 mutant, LTS23-1020, which failed to grow on but grew betaine. The mutant was deficient dehydrogenase (CDH) activity, oxidize [ methyl - 14 C]choline C]betaine, did not use choline, still used betaine, an osmoprotectant. mutation LTS23-1020 complemented by plasmid...
Abstract Senescence determines plant organ lifespan depending on aging and environmental cues. During the endosymbiotic interaction with rhizobia, legume plants develop a specific organ, root nodule, which houses nitrogen (N)‐fixing bacteria. Unlike earlier processes of legume–rhizobium (nodule formation, N fixation), mechanisms controlling nodule senescence remain poorly understood. To identify senescence‐associated genes, we performed dual plant‐bacteria RNA sequencing approach Medicago...
The symbiotic soil bacterium Sinorhizobium meliloti has the capacity to synthesize osmoprotectant glycine betaine from choline-O-sulfate and choline. This pathway is encoded by betICBA locus, which comprises a regulatory gene, betI, three structural genes, betC (choline sulfatase), betB (betaine aldehyde dehydrogenase), betA dehydrogenase). Here, we report that genes constitute single operon, despite existence of intergenic regions containing mosaic elements between betI betC, betA....
Rhizobia live in the soil or enter into a nitrogen-fixing symbiosis with suitable host plant. Each environment presents different challenges respect to iron acquisition. The soybean symbiont Bradyrhizobium japonicum 61A152 can utilize variety of siderophores (Fe[III]-specific ligands). Purification iron-regulated outer membrane proteins had previously allowed cloning gene, fegA, from B. ja-ponicum 61A152, whose predicted protein shares significant amino acid similarity known TonB-dependent...
ABSTRACT The symbiotic soil bacterium Sinorhizobium meliloti uses the compatible solutes glycine betaine and proline for both protection against osmotic stress and, at low osmolarities, as an energy source. A PCR strategy based on conserved domains in components of uptake systems from Escherichia coli (ProU) Bacillus subtilis (OpuA OpuC) allowed us to identify a highly homologous ATP-binding cassette (ABC) binding protein-dependent transporter S. . This system was encoded by three genes (...
Legumes are able to interact symbiotically with Rhizobia. This interaction gives rise a new organ, named nodule. Nodules characterized by an increased glutathione (GSH) content compared roots. In order characterize the modification of nodule activity induced microsymbiont deficiency, physiological, biochemical and gene expression modifications were analysed in nodules after inoculation Medicago truncatula SmgshB mutant Sinorhizobium meliloti which is deficient GSH production. The decline...
Abstract PRAF proteins are present in all plants, but their functions remain unclear. We investigated the role of one member family, Mt ZR1 , on development roots and nitrogen‐fixing nodules M edicago truncatula . found that MtZR1 was expressed organs. Spatiotemporal analysis showed expression mostly limited to root meristem vascular bundles mature nodules. down‐regulated response various abiotic stresses known affect nitrogen fixation efficiency. The down‐regulation by RNA interference...
Symbiotic N(2) fixation of legume crops is highly sensitive to drought, which results in a dramatic drop N accumulation and yield. The symbiosis between soybean (Glycine max) Bradyrhizobium japonicum, because its extreme sensitivity was chosen as model analyse the response drought stress at molecular level. mRNA differential display technique performed isolate cDNA markers differentially expressed well-watered [100% capacity (NFC)] drought-stressed nodules (40% NFC). One gene noted, G93,...
The symbiotic association of legumes with rhizobia results in the formation new root organs called nodules. However, lifespan nodules is limited by senescence process. Increased proteolytic activity one hallmarks nodule senescence. In Medicago truncatula, a papain cysteine protease encoding gene, MtCP6, marker for onset under both developmental and stress-induced pathways. To identify promoter regions conferring MtCP6 senescence-related expression, progressive deletions were generated...
Abstract Under nitrogen‐limiting conditions, legumes are able to form a symbiotic interaction with bacteria of the Rhizobiaceae family produce root nodules. These new organs satisfy plant nitrogen needs by reducing atmospheric ammonium. However, senescence these disturbs assimilation nitrogen. In this study, we present different histological, biochemical, and genetic markers natural nodule in Medicago truncatula over 10‐week period following bacterial inoculation. During aging length weight...