Saint-Georges-de-Luzençon, France
Saint-Georges-de-Luzençon, France

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Cock J.M.,CNRS Integrative Biology of Marine Models | Sterck L.,Vlaams Institute for Biotechnology | Sterck L.,Ghent University | Ahmed S.,CNRS Integrative Biology of Marine Models | And 99 more authors.
Advances in Botanical Research | Year: 2012

Brown algae are important organisms both because of their key ecological roles in coastal ecosystems and because of the remarkable biological features that they have acquired during their unusual evolutionary history. The recent sequencing of the complete genome of the filamentous brown alga Ectocarpus has provided unprecedented access to the molecular processes that underlie brown algal biology. Analysis of the genome sequence, which exhibits several unusual structural features, identified genes that are predicted to play key roles in several aspects of brown algal metabolism, in the construction of the multicellular bodyplan and in resistance to biotic and abiotic stresses. Information from the genome sequence is currently being used in combination with other genomic, genetic and biochemical tools to further investigate these and other aspects of brown algal biology at the molecular level. Here, we review some of the major discoveries that emerged from the analysis of the Ectocarpus genome sequence, with a particular focus on the unusual genome structure, inferences about brown algal evolution and novel aspects of brown algal metabolism. © 2012 Elsevier Ltd.

Heesch S.,CNRS Integrative Biology of Marine Models | Cho G.Y.,CNRS Integrative Biology of Marine Models | Peters A.F.,Bezhin Rosko | Le Corguille G.,Computer and Genomics Resource Center | And 8 more authors.
New Phytologist | Year: 2010

•Ectocarpus siliculosus has been proposed as a genetic and genomic model for the brown algae and the 214 Mbp genome of this organism has been sequenced. The aim of this project was to obtain a chromosome-scale view of the genome by constructing a genetic map using microsatellite markers that were designed based on the sequence supercontigs.•To map genetic markers, a segregating F2 population was generated from a cross between the sequenced strain (Ec 32) and a compatible strain from northern Chile. Amplified fragment length polymorphism (AFLP) analysis indicated a significant degree of polymorphism (41%) between the genomes of these two parental strains. Of 1,152 microsatellite markers that were selected for analysis based on their location on long supercontigs, their potential as markers and their predicted ability to amplify a single genomic locus, 407 were found to be polymorphic.•A genetic map was constructed using 406 markers, resulting in 34 linkage groups. The 406 markers anchor 325 of the longest supercontigs on to the map, representing 70.1% of the genome sequence.•The Ectocarpus genetic map described here not only provides a large-scale assembly of the genome sequence, but also represents an important tool for future genetic analysis using this organism. © The Authors (2010). Journal compilation © New Phytologist Trust (2010).

Ritter A.,University Pierre and Marie Curie | Ritter A.,French National Center for Scientific Research | Ritter A.,University of Santiago de Chile | Ubertini M.,University Pierre and Marie Curie | And 13 more authors.
Proteomics | Year: 2010

Ectocarpus siliculosus is a cosmopolitan brown alga with capacity to thrive in copper enriched environments. Analysis of copper toxicity was conducted in two strains of E. siliculosus isolated from (i) an uncontaminated coast in southern Peru (Es32) and (ii) a copper polluted rocky beach in northern Chile (Es524). Es32 was more sensitive than Es524, with toxicity detected at 50 mg/L Cu, whereas Es524 displayed negative effects only when exposed to 250 mg/L Cu. Differential soluble proteome profiling for each strain exposed to sub-lethal copper levels allowed to identify the induction of proteins related to processes such as energy production, glutathione metabolism as well as accumulation of HSPs. In addition, the inter-strain comparison of stress-related proteomes led to identify features related to copper tolerance in Es524, such as striking expression of a PSII Mn-stabilizing protein and a Fucoxanthine chlorophyll a-c binding protein. Es524 also expressed specific stress-related enzymes such as RNA helicases from the DEAD box families and a vanadium-dependent bromoperoxidase. These observations were supported by RT-qPCR for some of the identified genes and an enzyme activity assay for vanadium-dependent bromoperoxidase. Therefore, the occurrence of two different phenotypes within two distinct E. siliculosus strains studied at the physiological and proteomic levels strongly suggest that persistent copper stress may represent a selective force leading to the development of strains genetically adapted to copper contaminated sites. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.

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