Seaweeds influence oyster microbiota and disease susceptibility

• Published in: Journal of Animal Ecology
• Main Authors: Dugeny, Elyne, de Lorgeril, Julien, Petton, Bruno, Toulza, Eve, Gueguen, Yannick, Pernet, Fabrice
• Other Authors: Laboratoire des Sciences de l'Environnement Marin (LEMAR) (LEMAR), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Interactions Hôtes-Pathogènes-Environnements (IHPE), Université de Perpignan Via Domitia (UPVD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM), European Project: 678589,H2020,H2020-SFS-2015-2,VIVALDI(2016)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2022
• Subjects: bivalve; disease ecology; epidemiology; macroalgae; microbiome; pathogen; [SDV.BID.EVO]Life Sciences [q-bio]/Biodiversity/Populations and Evolution [q-bio.PE]; Pacific; Crassostrea gigas; Pacific oyster
• Online Access: https://hal.science/hal-03609497; https://hal.science/hal-03609497/document; https://hal.science/hal-03609497/file/Dugeny-2022-JAnimEcol-Seaweeds-MANUSCRIT.pdf; https://doi.org/10.1111/1365-2656.13662

International audience 1-A growing awareness of role that microbiota can play in mediating the effects of pathogens on hosts has given rise to the concept of the pathobiome. Recently, we demonstrated that the Pacific oyster mortality syndrome affecting Crassostrea gigas oysters is caused by infection with the Ostreid herpesvirus type 1 (OsHV-1) followed by infection with multiple bacterial taxa. 2-Here we extend the concept of this pathobiome beyond the host species and its bacterial microbiota by investigating how seaweed living in association with oysters influences their response to the disease. We hypothesized that by their mere presence in the environment, different species of seaweeds can positively or negatively influence the risk of disease in oysters by shaping their bacterial microbiota and their immune response. Although seaweed and oysters do not have direct ecological interactions, they are connected by seawater and likely share microbes. 3-To test our hypothesis, oysters were acclimated with green, brown or red algae for 2 weeks and then challenged with OsHV-1. We monitored host survival and pathogen proliferation and performed bacterial microbiota and transcriptome analyses. 4-We found that seaweeds can alter the bacterial microbiota of the host and its response to the disease. More particularly, green algae belonging to the genus Ulva spp. induced bacterial microbiota dysbiosis in oyster and modification of its transcriptional immune response leading to increased susceptibility to the disease. 5-This work provides a better understanding of a marine disease and highlights the importance of considering both macrobiotic and microbiotic interactions for conservation, management and exploitation of marine ecosystems and resources.