title: Disruption of amylase genes by RNA interference affects reproduction in the Pacific oyster Crassostrea gigas.
abstract: Feeding strategies and digestive capacities can have important implications for variation in energetic pathways associated with ecological and economically important traits, such as growth or reproduction in bivalve species. Here, we investigated the role of amylase in the digestive processes of Crassostrea gigas, using in vivo RNA interference. This approach also allowed us to investigate the relationship between energy intake by feeding and gametogenesis in oysters. Double-stranded (ds)RNA designed to target the two α-amylase genes A and B was injected in vivo into the visceral mass of oysters at two doses. These treatments caused significant reductions in mean mRNA levels of the amylase genes: -50.7% and -59% mRNA A, and -71.9% and -70.6% mRNA B in 15 and 75 µg dsRNA-injected oysters, respectively, relative to controls. Interestingly, reproductive knock-down phenotypes were observed for both sexes at 48 days post-injection, with a significant reduction of the gonad area (-22.5% relative to controls) and germ cell under-proliferation revealed by histology. In response to the higher dose of dsRNA, we also observed reductions in amylase activity (-53%) and absorption efficiency (-5%). Based on these data, dynamic energy budget modeling showed that the limitation of energy intake by feeding that was induced by injection of amylase dsRNA was insufficient to affect gonadic development at the level observed in the present study. This finding suggests that other driving mechanisms, such as endogenous hormonal modulation, might significantly change energy allocation to reproduction, and increase the maintenance rate in oysters in response to dsRNA injection.
authors.affiliation: Ifremer, UMR 6539 CNRS/UBO/IRD/Ifremer, Laboratoire des Sciences de l'Environnement Marin, Plouzané 29280, France ahuvet@ifremer.fr.
authors.forename: Arnaud
authors.initials: A
authors.lastname: Huvet
authors.affiliation: Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/Ifremer, Laboratoire des Sciences de l'Environnement Marin, Plouzané 29280, France.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Béguel
authors.affiliation: Laboratório Nacional de Computação Científica, Rua Getúlio Vargas 333, 25651-071 Petrópolis, Rio de Janeiro, Brazil.
authors.forename: Nathalia Pereira
authors.initials: NP
authors.lastname: Cavaleiro
authors.affiliation: Université de Nantes, Mer Molécules Santé EA 2160, Nantes 44322, Cedex 3, France.
authors.forename: Yoann
authors.initials: Y
authors.lastname: Thomas
authors.affiliation: Ifremer, UMR 6539 CNRS/UBO/IRD/Ifremer, Laboratoire des Sciences de l'Environnement Marin, Plouzané 29280, France.
authors.forename: Virgile
authors.initials: V
authors.lastname: Quillien
authors.affiliation: Ifremer, UMR 6539 CNRS/UBO/IRD/Ifremer, Laboratoire des Sciences de l'Environnement Marin, Plouzané 29280, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Boudry
authors.affiliation: Ifremer, UMR 6539 CNRS/UBO/IRD/Ifremer, Laboratoire des Sciences de l'Environnement Marin, Plouzané 29280, France.
authors.forename: Marianne
authors.initials: M
authors.lastname: Alunno-Bruscia
authors.affiliation: Institut Universitaire Européen de la Mer, Université de Bretagne Occidentale, UMR 6539 CNRS/UBO/IRD/Ifremer, Laboratoire des Sciences de l'Environnement Marin, Plouzané 29280, France.
authors.forename: Caroline
authors.initials: C
authors.lastname: Fabioux
mesh_terms: D000681:Amylases / Q000235:genetics* / Q000378:metabolism; D000818:Animals; D049896:Crassostrea / Q000235:genetics / Q000502:physiology*; D005260:Female; D005718:Gametogenesis / Q000502:physiology; D006066:Gonads / Q000502:physiology; D008297:Male; D034622:RNA Interference; D012098:Reproduction / Q000502:physiology
chemical_list: D000681:Amylases
keywords: Dynamic energy budget; Gametogenesis; Marine bivalve; dsRNA; α-Amylase