Roseobacticides: Small molecule modulators of an algal-bacterial symbiosis

Mohammad R. Seyedsayamdost, Gavin Carr, Roberto Kolter, Jon Clardy

Research output: Contribution to journalArticlepeer-review

115 Scopus citations


Marine bacteria and microalgae engage in dynamic symbioses mediated by small molecules. A recent study of Phaeobacter gallaeciensis, a member of the large roseobacter clade of α-proteobacteria, and Emiliania huxleyi, a prominent member of the microphytoplankton found in large algal blooms, revealed that an algal senescence signal produced by E. huxleyi elicits the production of novel algaecides, the roseobacticides, from the bacterial symbiont. In this report, the generality of these findings are examined by expanding the number of potential elicitors. This expansion led to the identification of nine new members of the roseobacticide family, rare bacterial troponoids, which provide insights into both their biological roles and their biosynthesis. The qualitative and quantitative changes in the levels of roseobacticides induced by the additional elicitors and the elicitors varied efficiencies support the concept of host-targeted roseobacticide production. Structures of the new family members arise from variable substituents at the C3 and C7 positions of the roseobacticide core as the diversifying elements and suggest that the roseobacticides result from modifications and combinations of aromatic amino acids. Together these studies support a model in which algal senescence converts a mutualistic bacterial symbiont into an opportunistic parasite of its hosts.

Original languageEnglish (US)
Pages (from-to)18343-18349
Number of pages7
JournalJournal of the American Chemical Society
Issue number45
StatePublished - Nov 16 2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General Chemistry
  • Biochemistry
  • Catalysis
  • Colloid and Surface Chemistry


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