Microbiota of three colormorphs of the precious coral Corallium rubrum

Corals engage in symbioses with micro-organisms that provide nutrients and protect the host. The microbiota of the coral Corallium rubrum is quite unique as it has a relatively low diversity and its dominant symbionts (e.g. Spirocheates, Parcubacteria) are not commonly found in other corals. As the white polyps harbour a different microbial community than the red-colored coenenchyme (tissue between the polyps), we investigated the microbiota of three colormorphs of C. rubrum (red, light pink and a very rare white colormorph) in order to assess whether microbes may play a role in this coral's color. We found a very low abundance of Spirochaeta in white colormorphs, similar as in the white polyps.