title: Transcriptional changes in Manila clam (Ruditapes philippinarum) in response to Brown Ring Disease.
abstract: Brown Ring Disease (BRD) is a bacterial infection affecting the economically-important clam Ruditapes philippinarum. The disease is caused by a bacterium, Vibrio tapetis, that colonizes the edge of the mantle, altering the biomineralization process and normal shell growth. Altered organic shell matrices accumulate on the inner face of the shell leading to the formation of the typical brown ring in the extrapallial space (between the mantle and the shell). Even though structural and functional changes have been described in solid (mantle) and fluid (hemolymph and extrapallial fluids) tissues from infected clams, the underlying molecular alterations and responses remain largely unknown. This study was designed to gather information on clam molecular responses to the disease and to compare focal responses at the site of the infection (mantle and extrapallial fluid) with systemic (hemolymph) responses. To do so, we designed and produced a Manila clam expression oligoarray (15K Agilent) using transcriptomic data available in public databases and used this platform to comparatively assess transcriptomic changes in mantle, hemolymph and extrapallial fluid of infected clams. Results showed significant regulation in diseased clams of molecules involved in pathogen recognition (e.g. lectins, C1q domain-containing proteins) and killing (defensin), apoptosis regulation (death-associated protein, bcl-2) and in biomineralization (shell matrix proteins, perlucin, galaxin, chitin- and calcium-binding proteins). While most changes in response to the disease were tissue-specific, systemic alterations included co-regulation in all 3 tested tissues of molecules involved in microbe recognition and killing (complement-related factors, defensin). These results provide a first glance at molecular alterations and responses caused by BRD and identify targets for future functional investigations.
authors.affiliation: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, USA. Electronic address: Bassem.Allam@stonybrook.edu.
authors.forename: Bassem
authors.initials: B
authors.lastname: Allam
authors.affiliation: School of Marine and Atmospheric Sciences, Stony Brook University, Stony Brook, NY, USA.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Pales Espinosa
authors.affiliation: Station Biologique de Roscoff, UPMC-CNRS, Roscoff, France.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Tanguy
authors.affiliation: Institut Universitaire Européen de la Mer, Plouzané, France.
authors.forename: Fanny
authors.initials: F
authors.lastname: Jeffroy
authors.affiliation: Institut Universitaire Européen de la Mer, Plouzané, France.
authors.forename: Cedric
authors.initials: C
authors.lastname: Le Bris
authors.affiliation: Institut Universitaire Européen de la Mer, Plouzané, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Paillard
mesh_terms: D000818:Animals; D049872:Bivalvia / Q000235:genetics / Q000276:immunology / Q000382:microbiology*; D020869:Gene Expression Profiling / Q000379:methods; D005786:Gene Expression Regulation / Q000235:genetics / Q000276:immunology*; D063990:Gene Ontology; D006458:Hemolymph / Q000276:immunology / Q000382:microbiology; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D059467:Transcriptome / Q000235:genetics / Q000276:immunology*; D014733:Vibrio / Q000276:immunology*
keywords: Biomineralization; Extrapallial fluid; Gene expression; Immunity; Oligoarray