Publication - Journal Article Trichodesmium genome maintains abundant, widespread noncoding DNA in situ, despite oligotrophic lifestyle

Proceedings of the National Academy of Sciences, vol. 112, iss. 14, pp. 4251-4256, 2015

Nathan Walworth, Ulrike Pfreundt, William C. Nelson, Tracy Mincer, John F. Heidelberg, Feixue Fu, John B. Waterbury, Tijana Glavina del Rio, Lynne Goodwin, Nikos C. Kyrpides, Miriam L. Land, Tanja Woyke, David A. Hutchins, Wolfgang R. Hess, Eric A. Webb

Significance The free-living cyanobacterium Trichodesmium is a major source of new nitrogen and fixed carbon to the tropical and subtropical oceans, but despite its importance, we know little about the molecular mechanisms it uses to succeed in its oligotrophic habitat. Here we show that its gene-sparse genome is littered with large, conserved, expressed intergenic spaces, which is atypical for most known free-living prokaryotes. Paradoxically, although its genome is enriched in predicted transposases and repeat sequences, it exhibits conserved intragenus synteny and similar intergenic architecture relative to its sympatric, gene-dense relatives Prochlorococcus and Synechococcus . This observation demonstrates a successful alternative to the genomic streamlining strategy observed in other free-living oligotrophs such as Prochlorococcus or Pelagibacter .