Taxonomic and Environmental Variation of Metabolite Profiles in Marine Dinoflagellates of the Genus Symbiodinium

Abstract

Microorganisms in terrestrial and marine ecosystems are essential to environmental sustainability. In the marine environment, invertebrates often depend on metabolic cooperation with their endosymbionts. Coral reefs, one of the most important marine ecosystems, are based on the symbiosis between a broad diversity of dinoflagellates of the genus Symbiodinium and a wide phyletic diversity of hosts (i.e., cnidarian, molluscan, poriferan). This diversity is reflected in the ecology and physiology of the symbionts, yet the underlying biochemical mechanisms are still poorly understood. We examined metabolite profiles of four cultured species of Symbiodinium known to form viable symbioses with reef-building corals, S. microadriaticum (cp-type A194), S. minutum (cp-type B184), S. psygmophilum (cp-type B224) and S. trenchii (cp-type D206). Metabolite profiles were shown to differ among Symbiodinium species and were found to be affected by their physiological response to growth in different temperatures and light regimes. A combined Random Forests and Bayesian analysis revealed that the four Symbiodinium species examined primarily differed in their production of sterols and sugars, including a C29 stanol and the two sterols C28Δ5 and C28Δ5,22, as well as differences in metabolite abundances of a hexose and inositol. Inositol levels were also strongly affected by changes in temperature across all Symbiodinium species. Our results offer a detailed view of the metabolite profile characteristic of marine symbiotic dinoflagellates of the genus Symbiodinium, and identify patterns of metabolites related to several growth conditions.

Correspondence of coral holobiont metabolome with symbiotic bacteria, archaea and Symbiodinium communities

“…While our approach advances the field by providing a framework to investigate the roles of the symbiotic partners in a complex milieu, further metagenomic approaches will provide a detailed comparison between the functions of different microbes (Dinsdale et al ., ). Our findings lend weight to growing information on the metabolic role of mixed microbial communities, with various Symbiodinium types characterized by different chemical profiles (Klueter et al ., ) and shifts in associated bacterial/archaeal communities altering the metabolic potential of the holobiont (Wegley et al ., ).…”

Mapping carbon fate during bleaching in a model cnidarian symbiosis: the application of 13C metabolomics

“…). These data also support a previous study with Symbiodinium in culture, which reported significant increases in pools of several inositol types (which were not identified) with elevated temperature in multiple Symbiodinium genotypes, suggesting that the accumulation of these groups may be a conserved response in Symbiodinium (Klueter et al ., ). Once again, the cellular roles of inositol derivatives and that of the wider signalling network within the cnidarian–dinoflagellate symbiosis warrant more in‐depth study; in particular, the potential roles of inositol in signal transduction in the holobiont during the breakdown of symbiosis (e.g.…”

Ocean acidification influences hostDNAmethylation and phenotypic plasticity in environmentally susceptible corals

“…) and their dinoflagellate symbionts (Klueter et al. ). This initial application was primarily concerned with methodology and reproducibility, but did identify differences in the metabolite profiles between coral species (Sogin et al.…”