Background Corals are known for their symbiotic relationships, yet there is limited evidence of chemoautotrophic associations. This is despite some corals occurring near cold seeps where chemosymbiotic fauna abound including mussels that host sulfur-oxidizing chemoautotrophs from the SUP05 cluster (family Ca. Thioglobaceae). We investigated whether corals near cold seeps associate with related bacteria and report here that these associations are widespread. Results We screened corals, water, and sediment for Thioglobaceae using 16S metabarcoding and found ASVs associated with corals at high relative abundance (10 – 91%). These ASVs were specific to coral hosts, absent in water samples, and rare or absent in sediment samples. Using metagenomics and transcriptomics, we assembled the genome of one phylotype associated with Paramuricea sp. B3 (ASV 4) which contained the genetic potential to oxidize sulfur and fix carbon, and confirmed that these pathways were transcriptionally active. Furthermore, its relative abundance was negatively correlated with the stable isotopic composition of its host coral’s tissue suggesting some contribution of chemoautotrophy to the coral holobiont. Conclusions We propose that some lineages of Thioglobaceae may facultatively supplement the diet of their host corals through chemoautotrophy at seeps or may provide essential amino acids or vitamins. This is the first documented association between chemoautotrophic symbionts and corals at seeps and suggests that the footprint of chemosynthetic environments is wider than currently understood.

Der Exzellenzcluster CIBSS – Centre for Integrative Biological Signalling Studies erforscht biologische Signale und entwickelt Lösungsansätze in den Bereichen Gesundheit und Ernährungssicherung.

Symbioses have been fundamental to colonization of terrestrial ecosystems by plants and their evolution. Emergence of the ancient arbuscular mycorrhizal symbiosis was followed by the diversification o...

Bienvenue dans Symbioses, le podcast qui célèbre le collectif et les réussites qui arrivent quand on décide de collaborer ensemble. Click to read Symbioses, by Symbioses, le podcast, a Substack public...

Whether looking out your window, or looking in your refrigerator, the view would be very different were it not for pollinators. Modern plants have evolved in concert with a diverse...

A symbiosis with arbuscular mycorrhizal fungi helps plants during nutrient shortages. But in legumes this is slightly different regulated. A new study analysing this finds that once the symbioses i…

As the ecological and evolutionary importance of symbiotic interactions between protists (microbial eukaryotes) and prokaryotes (bacteria and archaea) is better appreciated, keeping an overview of th...

Discovery of a marine diatom-associated Bradyrhizobium that nodulates a terrestrial legume expands our understanding of the environmental and host range of nitrogen-fixing symbioses.

Discovery of a marine diatom-associated Bradyrhizobium that nodulates a terrestrial legume expands our understanding of the environmental and host range of nitrogen-fixing symbioses.

YouTube video by MicrobeTV

The emergence of multicellularity and division of labor in cyanobacteria is a major evolutionary transition and remains elusive due to scarcity of fossil records. We investigate specialized cells used for nitrogen fixation by reconstructing the origin and evolution of molecules unique to their me...

The authors provide a molecular explanation for how a plant stress hormone called ethylene suppresses root colonization by arbuscular mycorrhiza fungi. These fungi form symbioses with most land plants...