Genome streamlining and chemical defense in a coral reef symbiosis

Jason C. Kwan, Mohamed S. Donia, Andrew W. Han, Euichi Hirose, Margo G. Haygood, Eric W. Schmidt

Research output: Contribution to journalArticlepeer-review

115 Scopus citations


Secondary metabolites are ubiquitous in bacteria, but by definition, they are thought to be nonessential. Highly toxic secondary metabolites such as patellazoles have been isolated from marine tunicates, where their exceptional potency and abundance implies a role in chemical defense, but their biological source is unknown. Here, we describe the association of the tunicate Lissoclinum patella with a symbiotic α-proteobacterium, Candidatus Endolissoclinum faulkneri, and present chemical and biological evidence that the bacterium synthesizes patellazoles. We sequenced and assembled the complete Ca. E. faulkneri genome, directly from metagenomic DNA obtained from the tunicate, where it accounted for 0.6% of sequence data. We show that the large patellazoles biosynthetic pathway is maintained, whereas the remainder of the genome is undergoing extensive streamlining to eliminate un-needed genes. The preservation of this pathway in streamlined bacteria demonstrates that secondary metabolism is an essential component of the symbiotic interaction.

Original languageEnglish (US)
Pages (from-to)20655-20660
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number50
StatePublished - Dec 11 2012
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General


  • Ascidian
  • Biosynthesis
  • Natural products
  • Polyketide
  • Trans-acyltransferase


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