title: Complex microbiome underlying secondary and primary metabolism in the tunicate-Prochloron symbiosis.
abstract: The relationship between tunicates and the uncultivated cyanobacterium Prochloron didemni has long provided a model symbiosis. P. didemni is required for survival of animals such as Lissoclinum patella and also makes secondary metabolites of pharmaceutical interest. Here, we present the metagenomes, chemistry, and microbiomes of four related L. patella tunicate samples from a wide geographical range of the tropical Pacific. The remarkably similar P. didemni genomes are the most complex so far assembled from uncultivated organisms. Although P. didemni has not been stably cultivated and comprises a single strain in each sample, a complete set of metabolic genes indicates that the bacteria are likely capable of reproducing outside the host. The sequences reveal notable peculiarities of the photosynthetic apparatus and explain the basis of nutrient exchange underlying the symbiosis. P. didemni likely profoundly influences the lipid composition of the animals by synthesizing sterols and an unusual lipid with biofuel potential. In addition, L. patella also harbors a great variety of other bacterial groups that contribute nutritional and secondary metabolic products to the symbiosis. These bacteria possess an enormous genetic potential to synthesize new secondary metabolites. For example, an antitumor candidate molecule, patellazole, is not encoded in the genome of Prochloron and was linked to other bacteria from the microbiome. This study unveils the complex L. patella microbiome and its impact on primary and secondary metabolism, revealing a remarkable versatility in creating and exchanging small molecules.
authors: Department of Medicinal Chemistry, University of Utah, Salt Lake City, UT 84112, USA.
authors: Mohamed S
authors: MS
authors: Donia
authors: W Florian
authors: WF
authors: Fricke
authors: Frédéric
authors: F
authors: Partensky
authors: James
authors: J
authors: Cox
authors: Sherif I
authors: SI
authors: Elshahawi
authors: James R
authors: JR
authors: White
authors: Adam M
authors: AM
authors: Phillippy
authors: Michael C
authors: MC
authors: Schatz
authors: Joern
authors: J
authors: Piel
authors: Margo G
authors: MG
authors: Haygood
authors: Jacques
authors: J
authors: Ravel
authors: Eric W
authors: EW
authors: Schmidt
mesh_terms: D000818:Animals; D016678:Genome; D023281:Genomics; D054892:Metagenome / Q000502:physiology*; D056186:Metagenomics; D008954:Models, Biological; D008957:Models, Genetic; D008969:Molecular Sequence Data; D010788:Photosynthesis; D010802:Phylogeny; D019691:Prochloron / Q000378:metabolism*; D012336:RNA, Ribosomal, 16S / Q000378:metabolism; D017422:Sequence Analysis, DNA; D013559:Symbiosis; D014561:Urochordata
chemical_list: D012336:RNA, Ribosomal, 16S