A5086944434- Protist diversity and phylogeny
- Microbial Community Ecology and Physiology
- Algal biology and biofuel production
- Light effects on plants
- Circadian rhythm and melatonin
- Plant Molecular Biology Research
- Photosynthetic Processes and Mechanisms
- Marine and coastal ecosystems
- Photoreceptor and optogenetics research
- Marine and coastal plant biology
- Diatoms and Algae Research
- Microtubule and mitosis dynamics
- Genomics and Phylogenetic Studies
- Folate and B Vitamins Research
- bioluminescence and chemiluminescence research
- Gene Regulatory Network Analysis
- Plant Reproductive Biology
- Plant nutrient uptake and metabolism
- Cancer-related Molecular Pathways
- Microbial Fuel Cells and Bioremediation
- Steroid Chemistry and Biochemistry
- Marine Biology and Ecology Research
- Plant and Biological Electrophysiology Studies
- Marine Biology and Environmental Chemistry
- Animal Genetics and Reproduction
Centre National de la Recherche Scientifique
2014-2025
Sorbonne Université
2015-2025
Laboratoire d'Océanographie Microbienne
2015-2025
Observatoire Océanologique de Banyuls-sur-Mer
2005-2020
Université Paris Cité
2012-2019
Institut de Chimie de Nice
2018
Centre National pour la Recherche Scientifique et Technique (CNRST)
2012
Marie Curie
2012
Charles University
2012
Vlaams Instituut voor Biotechnologie
2006
The green lineage is reportedly 1,500 million years old, evolving shortly after the endosymbiosis event that gave rise to early photosynthetic eukaryotes. In this study, we unveil complete genome sequence of an ancient member lineage, unicellular alga Ostreococcus tauri (Prasinophyceae). This cosmopolitan marine primary producer world's smallest free-living eukaryote known date. Features likely reflecting optimization environmentally relevant pathways, including resource acquisition, unusual...
Red seaweeds are key components of coastal ecosystems and economically important as food a source gelling agents, but their genes genomes have received little attention. Here we report the sequencing 105-Mbp genome florideophyte Chondrus crispus (Irish moss) annotation 9,606 genes. The features an unusual structure characterized by gene-dense regions surrounded repeat-rich dominated transposable elements. Despite its fairly large size, this shows typical compact genomes, e.g., on average...
Abstract Diverse microbial ecosystems underpin life in the sea. Among these microbes are many unicellular eukaryotes that span diversity of eukaryotic tree life. However, genetic tractability has been limited to a few species, which do not represent or environmentally relevant taxa. Here, we report on development tools range protists primarily from marine environments. We present evidence for foreign DNA delivery and expression 13 species never before transformed advancement eight other as...
To identify molecular players implicated in cytokinesis and division plane determination, the Arabidopsis thaliana genome was explored for potential genes. More than 100 open reading frames were selected based on similarity to yeast animal genes, cytoskeleton polarity Nicotiana tabacum genes showing cell cycle-controlled expression. The subcellular localization of these proteins determined by means GFP tagging tobacco Bright Yellow-2 cells plants. Detailed confocal microscopy identified 15...
Abstract Biological rhythms that allow organisms to adapt the solar cycle are generated by endogenous circadian clocks. In higher plants, many clock components have been identified and cellular rhythmicity is thought be driven a complex transcriptional feedback circuitry. small genome of green unicellular alga Ostreococcus tauri, two master genes Timing Cab expression1 (TOC1) Circadian Clock-Associated1 (CCA1) appear conserved, but others like Gigantea or Early-Flowering4 lacking. Stably...
Abstract Background Picoeukaryotes represent an important, yet poorly characterized component of marine phytoplankton. The recent genome availability for two species Ostreococcus and Micromonas has led to the emergence picophytoplankton comparative genomics. Sequencing revealed many unexpected features about structure several hypotheses on biology physiology. Despite accumulation genomic data, little is known gene expression in eukaryotic picophytoplankton. Results We have conducted a...
Cryptochromes (Crys) are blue light receptors believed to have evolved from the DNA photolyase protein family, implying that control and protection share a common ancient origin. In this paper, we report identification of five genes Cry/photolyase family (CPF) in two green algae Ostreococcus genus. Phylogenetic analyses were used confidently assign three these sequences cyclobutane pyrimidine dimer (CPD) photolyases, one them DASH-type Cry, third CPF gene has high homology with recently...
Abstract TPLATE was previously identified as a potential cytokinesis protein targeted to the cell plate. Disruption of in Arabidopsis thaliana leads production shriveled pollen unable germinate. Vesicular compartmentalization mature is dramatically altered, and large callose deposits accumulate near intine wall layer. Green fluorescent (GFP)–tagged expression under control promoter Lat52 complements phenotype. Downregulation seedlings tobacco (Nicotiana tabacum) BY-2 suspension cells results...
Cost effective next generation sequencing technologies now enable the production of genomic datasets for many novel planktonic eukaryotes, representing an understudied reservoir genetic diversity. O. tauri is smallest free-living photosynthetic eukaryote known to date, a coccoid green alga that was first isolated in 1995 lagoon by Mediterranean sea. Its simple features, ease culture and its 13 Mb haploid nuclear genome have promoted this microalga as new model organism cell biology. Here, we...
Abstract We investigated iron uptake mechanisms in five marine microalgae from different ecologically important phyla: the diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana, prasinophyceae Ostreococcus tauri Micromonas pusilla, coccolithophore Emiliania huxleyi. Among these species, only two were clearly able to reduce iron, via an inducible (P. tricornutum) or constitutive (T. pseudonana) ferrireductase system displaying characteristics similar yeast (Saccharomyces cerevisiae)...
Although the decision to proceed through cell division depends largely on metabolic status or size of cell, timing is often set by internal clocks such as circadian clock. Light a major cue for clock entrainment, and photosynthetic organisms it also main source energy supporting growth prior division. Little known about how light signals are integrated in control S phase entry. Here, we present an study light-dependent regulation marine green alga Ostreococcus. During early G1, genes were...
Circadian clocks are biological timekeepers that allow living cells to time their activity in anticipation of predictable environmental changes. Detailed understanding the circadian network higher plants, such as Arabidopsis thaliana, is hampered by high number partially redundant genes. However, picoeukaryotic alga Ostreococcus tauri, which was recently shown possess a small non-redundant clock genes, presents an attractive alternative target for detailed modelling green lineage. Based on...
In large regions of the open ocean, iron is a limiting resource for phytoplankton. The reduction quota and recycling internal pools are among diverse strategies that phytoplankton have evolved to allow them grow under chronically low ambient levels. Phytoplankton species also cope with sporadic supply such as long-term storage in ferritin. picophytoplanktonic Ostreococcus we report evidence from observations both field laboratory cultures ferritin main iron-binding proteins involved...
Several cosmopolitan marine picoeukaryotic phytoplankton are B1 auxotrophs requiring exogenous vitamin or precursor to survive. From genomic evidence, representatives of (Ostreococcus and Micromonas spp.) were predicted use known thiazole pyrimidine precursors meet their demands, however, recent culture-based experiments could not confirm this assumption. We hypothesized these strains grow on alone, but required a thiazole-related other the well-known extensively tested...
Summary Marine picoplankton contribute to global carbon sequestration and nutrient recycling. These processes are directly related the composition of communities, which in turn depends on microbial interactions environmental forcing. Under regular seasonal cycles, marine communities show strong predictable patterns annual re‐occurrences, but little is known about effect perturbation their organization. The aim our study was investigate co‐occurrence planktonic picoeukaryote, bacteria archaea...
The marine environment has unique properties of light transmission, with an attenuation long wavelengths within the first meters water column. Marine organisms have therefore evolved specific blue-light receptors such as aureochromes to absorb shorter-wavelength light. Here, we identify and characterize a light, oxygen, or voltage sensing (LOV) containing histidine kinase (LOV-HK) that functions new class eukaryotic receptor in pico-phytoplanktonic cell Ostreococcus tauri. This LOV-HK is...
With fewer than 8000 genes and a minimalist cellular organization, the green picoalga Ostreococcus tauri is one of simplest photosynthetic eukaryotes. contains many plant-specific but exhibits very low gene redundancy. The haploid genome extremely dense with few repeated sequences rare transposons. Thanks to implementation genetic transformation vectors for inducible overexpression/knockdown this picoeukaryotic alga has emerged in recent years as model organism functional genomics analyses...
Iron (Fe) is an essential element for marine microbial growth but present in trace amounts (<0.1 nM) surface waters of the ocean. In heterotrophic bacteria, Fe-limitation particularly impacts ATP production as Fe co-factor enzymes involved electron-transport chain well tricarboxylic acid (TCA) cycle. can therefore drastically reduce both bacterial and respiration, consequently affecting efficiency organic carbon remineralization. Heterotrophic bacteria possess various strategies to cope with...
The development of systemic approaches in biology has put emphasis on identifying genetic modules whose behavior can be modeled accurately so as to gain insight into their structure and function. However, most gene circuits a cell are under control external signals thus, quantitative agreement between experimental data mathematical model is difficult. Circadian been one notable exception: models the internal clock that orchestrates biological processes over 24-hour diurnal cycle have...
The Earth's rotation has driven the evolution of cellular circadian clocks to facilitate anticipation solar cycle. Some evidence for timekeeping mechanism conserved from early unicellular life through modern organisms was recently identified, but components this oscillator are currently unknown. Although very few clock appear be shared across higher species, Casein Kinase 1 (CK1) is known affect metazoans and fungi, not previously been implicated in plant kingdom. We now show that modulation...
Low iron bioavailability is a common feature of ocean surface water and therefore micro-algae developed original strategies to optimize uptake metabolism. The marine picoeukaryotic green alga Ostreococcus tauri very good model for studying physiological genetic aspects the adaptation algal lineage environment: it has compact genome, easy culture in laboratory conditions, can be genetically manipulated by efficient homologous recombination. In this study, we aimed at characterizing mechanisms...
ABSTRACT The early embryo of the brown alga Fucus comprises two cell types, i.e. rhizoid and thallus which are morphogically cytologically distinguishable. Previous work has pointed to wall as a source position-dependent information required for polarisation fate determination in zygote 2-celled embryo. In this study we have analysed mechanism(s) control pattern formation at later embryonic stages using combination laser microsurgery microinjection. results indicate that is maintenance...
Abstract Cyclin-dependent kinases (CDKs) are the main regulators of cell cycle progression in eukaryotes. The role and regulation canonical CDKs, such as yeast (Saccharomyces cerevisiae) Cdc2 or plant CDKA, have been extensively characterized. However, function plant-specific CDKB is not well understood. Besides being involved control, Arabidopsis (Arabidopsis thaliana) would integrate developmental processes to progression. We investigated Ostreococcus (Ostreococcus tauri), a unicellular...