Metabarcoding reveals distinct microbiotypes in the giant clam Tridacna maxima

Guibert, Isis, Lecellier, Gael, Torda, Gergely, Pochon, Xavier, and Berteaux-Lecellier, Véronique (2020) Metabarcoding reveals distinct microbiotypes in the giant clam Tridacna maxima. Microbiome, 8. 57.

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Giant clams and scleractinian (reef-building) corals are keystone species of coral reef ecosystems. The basis of their ecological success is a complex and fine-tuned symbiotic relationship with microbes. While the effect of environmental change on the composition of the coral microbiome has been heavily studied, we know very little about the composition and sensitivity of the microbiome associated with clams. Here, we explore the influence of increasing temperature on the microbial community (bacteria and dinoflagellates from the family Symbiodiniaceae) harbored by giant clams, maintained either in isolation or exposed to other reef species. We created artificial benthic assemblages using two coral species (Pocillopora damicornis and Acropora cytherea) and one giant clam species (Tridacna maxima) and studied the microbial community in the latter using metagenomics.


Our results led to three major conclusions. First, the health status of giant clams depended on the composition of the benthic species assemblages. Second, we discovered distinct microbiotypes in the studied T. maxima population, one of which was disproportionately dominated by Vibrionaceae and directly linked to clam mortality. Third, neither the increase in water temperature nor the composition of the benthic assemblage had a significant effect on the composition of the Symbiodiniaceae and bacterial communities of T. maxima.


Altogether, our results suggest that at least three microbiotypes naturally exist in the studied clam populations, regardless of water temperature. These microbiotypes plausibly provide similar functions to the clam host via alternate molecular pathways as well as microbiotype-specific functions. This redundancy in functions among microbiotypes together with their specificities provides hope that giant clam populations can tolerate some levels of environmental variation such as increased temperature. Importantly, the composition of the benthic assemblage could make clams susceptible to infections by Vibrionaceae, especially when water temperature increases.

Item ID: 63203
Item Type: Article (Research - C1)
ISSN: 2049-2618
Keywords: Giant clams, Assemblages, Microbiome, Symbiodiniaceae, Microbiotype
Copyright Information: © The Author(s). 2020 Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.
Funders: LabexCorail, French National Centre for Scientific Research (CNRS), Sorbonne University
Date Deposited: 20 May 2020 07:33
FoR Codes: 31 BIOLOGICAL SCIENCES > 3105 Genetics > 310506 Gene mapping @ 100%
SEO Codes: 19 ENVIRONMENTAL POLICY, CLIMATE CHANGE AND NATURAL HAZARDS > 1901 Adaptation to climate change > 190102 Ecosystem adaptation to climate change @ 100%
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