Trichodesmium genome maintains abundant, widespread noncoding DNA in situ, despite oligotrophic lifestyle
Abstract
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.
- Publication:
-
Proceedings of the National Academy of Science
- Pub Date:
- April 2015
- DOI:
- 10.1073/pnas.1422332112
- Bibcode:
- 2015PNAS..112.4251W