A5060444520- Photosynthetic Processes and Mechanisms
- Algal biology and biofuel production
- Agriculture and Rural Development Research
- Metalloenzymes and iron-sulfur proteins
- African Botany and Ecology Studies
- Soil Carbon and Nitrogen Dynamics
- Electrocatalysts for Energy Conversion
- Rangeland Management and Livestock Ecology
- Marine and coastal ecosystems
- Photoreceptor and optogenetics research
- Plant Water Relations and Carbon Dynamics
- Plant nutrient uptake and metabolism
- Agronomic Practices and Intercropping Systems
- Hydrogen Storage and Materials
- Light effects on plants
- Mitochondrial Function and Pathology
- Ecology and Vegetation Dynamics Studies
- Microbial Community Ecology and Physiology
- Plant-Microbe Interactions and Immunity
- Rice Cultivation and Yield Improvement
- Legume Nitrogen Fixing Symbiosis
- Advanced battery technologies research
- Agroforestry and silvopastoral systems
- Plant responses to elevated CO2
- Spectroscopy and Quantum Chemical Studies
Ecologie fonctionnelle & biogéochimie des sols & des agro-systèmes
2016-2025
Institut de Recherche pour le Développement
2015-2025
Institut Agro Montpellier
2014-2025
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
2020-2025
Centre de Coopération Internationale en Recherche Agronomique pour le Développement
2016-2025
Université de Montpellier
2018-2025
Institut Sénégalais de Recherches Agricoles
2017-2024
LMI Adaptation des Plantes et Microorganismes Associés aux Stress Environnementaux
2018-2024
Institut de Recherche pour le Développement
2019-2023
Forschungsinstitut für Biologischen Landbau
2023
Cyanobacterial flavodiiron proteins (FDPs; A-type flavoprotein, Flv) comprise, besides the β-lactamase-like and flavodoxin domains typical for all FDPs, an extra NAD(P)H:flavin oxidoreductase module thus differ from FDPs in other Bacteria Archaea. Synechocystis sp. PCC 6803 has four genes encoding FDPs. Flv1 Flv3 function as NAD(P)H:oxygen oxidoreductase, donating electrons directly to O2 without production of reactive oxygen species. Here we show that are crucial cyanobacteria under...
The unicellular green alga Chlamydomonas reinhardtii is a prime model for deciphering processes occurring in the intracellular compartments of photosynthetic cell. Organelle-specific proteomic studies have started to delineate its various subproteomes, but sequence-based prediction software necessary assign proteins subcellular localizations at whole genome scale. Unfortunately, existing tools are oriented toward land plants and tend mispredict localization nuclear-encoded algal proteins,...
Abstract Background The rhizosheath, a cohesive soil layer firmly adhering to plant roots, plays vital role in facilitating water and mineral uptake. In pearl millet, rhizosheath formation is genetically controlled influenced by root exudates. Here, we investigated the impact of exudates on microbiota composition, interactions, assembly processes, structure millet using four distinct lines with contrasting aggregation abilities. Results Utilizing 16S rRNA gene ITS metabarcoding for...
The ndh genes encoding for the subunits of NAD(P)H dehydrogenase complex represent largest family plastid without a clearly defined function. Tobacco (Nicotiana tabacum) transformants were produced in which thendhB gene was inactivated by replacing it with mutant version possessing translational stops coding region. Western-blot analysis indicated that no functional can be assembled transformants. Chlorophyll fluorescence measurements showed dark reduction plastoquinone pool stromal...
The interaction between hydrogen metabolism, respiration, and photosynthesis was studied in vivo whole cells of Synechocystis sp. strain PCC 6803 by continuously monitoring the changes gas concentrations (H2, CO2, O2) with an online mass spectrometer. activity bidirectional [NiFe]hydrogenase [H2:NAD(P) oxidoreductase], encoded hoxEFUYH genes, also measured independently proton-deuterium (H-D) exchange reaction presence D2. This technique allowed us to demonstrate that hydrogenase insensitive...
An inducible chloroplast gene expression system was developed in Chlamydomonas reinhardtii by taking advantage of the properties copper-sensitive cytochrome c(6) promoter and nucleus-encoded Nac2 protein. This protein is specifically required for stable accumulation psbD RNA acts on its 5' UTR. A construct containing coding sequence fused to introduced into nac2-26 mutant strain deficient Nac2. In this transformant, expressed copper-depleted but not copper-replete medium. Because encodes D2...
In photosynthetic eukaryotes, nonphotochemical plastoquinone (PQ) reduction is important for the regulation of electron flow. green microalgae where this process has been demonstrated, chloroplastic enzyme that catalyses PQ not identified yet. Here, we show by an RNA interference (RNAi) approach NDA2 gene, belonging to a type II NAD(P)H dehydrogenases family in microalga Chlamydomonas reinhardtii, encodes dehydrogenase functions reduce nonphotochemically alga. Using specific antibody, Nda2...
Hydrogen photoproduction by eukaryotic microalgae results from a connection between the photosynthetic electron transport chain and plastidial hydrogenase. Algal H2 production is transitory phenomenon under most natural conditions, often viewed as safety valve protecting overreduction. From colony screening of an insertion mutant library unicellular green alga Chlamydomonas reinhardtii based on analysis dark-light chlorophyll fluorescence transients, we isolated impaired in cyclic flow...
In Chlamydomonas reinhardtii cells, H2 photoproduction can be induced in conditions of sulfur deprivation the presence acetate. The decrease photosystem II (PSII) activity by leads to anoxia, respiration becoming higher than photosynthesis, thereby allowing production. Two different electron transfer pathways, one PSII dependent and other independent, have been proposed account for photoproduction. this study, we investigated contribution both pathways as well acetate requirement production...
Abstract Under sulfur deprivation conditions, the green alga Chlamydomonas reinhardtii produces hydrogen in light a sustainable manner thanks to contribution of two pathways, direct and indirect. In pathway, photosystem II (PSII) supplies electrons hydrogenase through photosynthetic electron transport chain, while indirect is produced absence PSII I-dependent process. Starch metabolism has been proposed contribute both pathways by feeding respiration maintaining anoxia during pathway...
Hydrogenases, which catalyze H 2 to + conversion as part of the bioenergetic metabolism many microorganisms, are among metalloenzymes for a gas-substrate tunnel has been described by using crystallography and molecular dynamics. However, correlation between protein structure gas-diffusion kinetics is unexplored. Here, we introduce two quantitative methods probing rates diffusion within hydrogenases. One uses film voltammetry resolve binding release competitive inhibitor CO; other based on...
Electron transfer pathways associated to oxygenic photosynthesis, including cyclic electron flow around photosystem I and chlororespiration, rely on non-photochemical reduction of plastoquinones (PQs). In higher plant chloroplasts, a bacterial-like NDH complex homologous is involved in PQ reduction, but such absent from Chlamydomonas plastids where type II NAD(P)H dehydrogenase activity has been proposed operate. With the aim elucidate nature enzyme-supporting PQs, one dehydrogenases...
Flavodiiron (Flv) proteins are involved in detoxification of O(2) and NO anaerobic bacteria archaea. Cyanobacterial Flv proteins, on the contrary, function oxygenic environment possess an extra NAD(P)H:flavin oxidoreductase module. Synechocystis sp. PCC 6803 has four genes (sll1521, sll0219, sll0550, sll0217) encoding (Flv1, Flv2, Flv3, Flv4). Previous vitro studies with recombinant Flv3 protein from provided evidence that it functions as a NAD(P)H:oxygen oxidoreductase, subsequent vivo...
When enzymes are optimized for biotechnological purposes, the goal often is to increase stability or catalytic efficiency. However, many reversibly convert their substrate and product, if one interested in catalysis only direction, it may be necessary prevent reverse reaction. In other cases, reversibility advantageous because an enzyme that can operate both directions turnover at a high rate even under conditions of low thermodynamic driving force. Therefore, understanding basic mechanisms...
Abstract Cyclic electron flow around photosystem (PS) I has been widely described in vitro chloroplasts or thylakoids isolated from C3 plant leaves, but its occurrence vivo is still a matter of debate. Photoacoustic spectroscopy and kinetic spectrophotometry were used to analyze cyclic PS activity tobacco (Nicotiana tabacum cv Petit Havana) leaf discs illuminated with far-red light. Only very weak was measured air both techniques. When placed anaerobiosis, high rapid measured. The maximal...
In <i>Chlamydomonas reinhardtii</i> mutants deficient in photosystem I because of inactivation the chloroplast genes <i>psaA</i> or <i>psaB</i>, oxygen evolution from II occurs at significant rates and is coupled to a stimulation uptake. Both activities can be simultaneously monitored by continuous mass spectrometry presence of<sup>18</sup>O<sub>2</sub>. The light-driven O<sub>2</sub> exchange was shown involve plastoquinone pool as an electron carrier, but not cytochrome <i>b</i>...
Chlororespiration has been defined as a respiratory electron transport chain in interaction with photosynthetic involving both non-photochemical reduction and oxidation of plastoquinones. Different enzymatic activities, including plastid-encoded NADH dehydrogenase complex, have reported to be involved the However, enzyme responsible for plasquinol not yet clearly identified. In order determine whether newly discovered plastid oxidase (PTOX) carotenoid biosynthesis acts plastoquinol higher...
Summary Among the three distinct starch phosphorylase activities detected in Chlamydomonas reinhardtii , two plastidial enzymes (PhoA and PhoB) are documented while a single extraplastidial form (PhoC) displays higher affinity for glycogen as vascular plants. The phosphorylases shown to function homodimers containing 91‐kDa (PhoA) subunits 110‐kDa (PhoB) subunits. Both lack typical 80‐amino‐acid insertion found plant forms. PhoB is exquisitely sensitive inhibition by ADP‐glucose has low...
Hydrogenases catalyze the conversion between 2H(+) + 2e(-) and H(2)(1). Most of these enzymes are inhibited by O(2), which represents a major drawback for their use in biotechnological applications. Improving hydrogenase O(2) tolerance is therefore contemporary challenge to allow implementation sustainable hydrogen economy. We succeeded improving tolerance, we define here as ability enzyme resist several minutes exposure, substituting with methionines small hydrophobic residues strongly...