Chemical surprises from an uncultivated sponge symbiont

Marine sponges are a rich source of bioactive natural products and are promising sources for drug discovery and development An impressive example is the sponge Theonella swinhoei, which has yielded more than 120 compounds belonging to diverse structural types. Many sponges also harbor highly complex consortia of symbiotic bacteria that are suspected to be the true source of at least some of the secondary metabolites. In previous work, our group demonstrated a bacterial origin of onnamide- and psymberin-type polyketides for two different sponges (1–3), but there were no insights into the producer of compounds from other natural product families. In addition, the exact taxonomic identity of sponge-associated producers remained unknown.