Diverse Microbial Community Found on Sea Squirt Coat


The sea squirt Ciona intestinalis is a well-studied model organism in developmental biology. Ciona is the closest invertebrate relative to the chordate (backboned) lineage to which humans and other primates belong. Little is known about its associated bacterial community in spite of growing evidence that microbes play key roles in organisms from plants to humans. New research supported by the Department of Energy’s Joint Genome Institute (DOE JGI) combined several technologies to characterize the bacteria living inside and on the exterior coating, or tunic, of C. intestinalis adults. The Ciona tunic is a complex cellulose and mucopolysaccharide envelope; the sequencing data demonstrates that the bacterial community structure on Ciona’s tunic differs from that of bacteria in the surrounding seawater. The observed tunic bacterial consortium contains a shared community of less than 10 abundant bacterial phylotypes across three individuals. The relatively simple bacterial community and availability of dominant community members in culture make C. intestinalis a promising system in which to investigate functional interactions between host-associated microbiota and bacterial enzymes that could digest or alter celluloses. Leveraging the original sequencing work of the C. intestinalis by DOE JGI, this work was supported by an interagency program, the International Collaborative Biodiversity Group program administered by the National Institutes of Health’s Fogarty International Center, in which multiple agencies participated.


Blasiak, L. C., S. H. Zinder, D. H. Buckley, and R. T. Hill. 2014. “Bacterial Diversity Associated with the Tunic of the Model Chordate Ciona intestinalis,” The ISME Journal 8, 309–20. DOI:10.1038/ismej.2013.156.