title: Copper stress proteomics highlights local adaptation of two strains of the model brown alga Ectocarpus siliculosus.
abstract: 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 microg/L Cu, whereas Es524 displayed negative effects only when exposed to 250 microg/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.
authors.affiliation: Université Pierre et Marie Curie-Paris 6, Végétaux Marins et Biomolécules, Station Biologique, Place Georges Teissier, Roscoff, France.
authors.forename: Andrés
authors.initials: A
authors.lastname: Ritter
authors.forename: Martin
authors.initials: M
authors.lastname: Ubertini
authors.forename: Sarah
authors.initials: S
authors.lastname: Romac
authors.forename: Fanny
authors.initials: F
authors.lastname: Gaillard
authors.forename: Ludovic
authors.initials: L
authors.lastname: Delage
authors.forename: Aaron
authors.initials: A
authors.lastname: Mann
authors.forename: J Mark
authors.initials: JM
authors.lastname: Cock
authors.forename: Thierry
authors.initials: T
authors.lastname: Tonon
authors.forename: Juan A
authors.initials: JA
authors.lastname: Correa
authors.forename: Philippe
authors.initials: P
authors.lastname: Potin
mesh_terms: D000222:Adaptation, Physiological; D003300:Copper / Q000633:toxicity*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D000459:Phaeophyceae / Q000187:drug effects* / Q000378:metabolism*; D040901:Proteomics / Q000379:methods*
chemical_list: D003300:Copper