Evidence for polyploidy in the globally important diazotroph Trichodesmium

Elizabeth C. Sargent, Andrew Hitchcock, S. Andreas Johansson, Rebecca Langlois, C. Mark Moore, Julie LaRoche, Alex J. Poulton, Thomas S. Bibby

Research output: Contribution to journalLetter

18 Citations (Scopus)

Abstract

Polyploidy is a well-described trait in some prokaryotic organisms; however, it is unusual in marine microbes from oligotrophic environments, which typically display a tendency towards genome streamlining. The biogeochemically significant diazotrophic cyanobacterium Trichodesmium is a potential exception. With a relatively large genome and a comparatively high proportion of non-protein-coding DNA, Trichodesmium appears to allocate relatively more resources to genetic material than closely related organisms and microbes within the same environment. Through simultaneous analysis of gene abundance and direct cell counts, we show for the first time that Trichodesmium spp. can also be highly polyploid, containing as many as 100 genome copies per cell in field-collected samples and >600 copies per cell in laboratory cultures. These findings have implications for the widespread use of the abundance of the nifH gene (encoding a subunit of the N2-fixing enzyme nitrogenase) as an approach for quantifying the abundance and distribution of marine diazotrophs. Moreover, polyploidy may combine with the unusual genomic characteristics of this genus both in reflecting evolutionary dynamics and influencing phenotypic plasticity and ecological resilience.

Original languageEnglish
Article numberfnw244
JournalFEMS Microbiology Letters
Volume363
Issue number21
DOIs
Publication statusPublished - 25 Oct 2016

Keywords

  • Cyanobacteria
  • Diazotroph
  • nifH
  • Nitrogenase
  • Polyploidy
  • Trichodesmium

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology
  • Genetics

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  • Cite this

    Sargent, E. C., Hitchcock, A., Johansson, S. A., Langlois, R., Moore, C. M., LaRoche, J., Poulton, A. J., & Bibby, T. S. (2016). Evidence for polyploidy in the globally important diazotroph Trichodesmium. FEMS Microbiology Letters, 363(21), [fnw244]. https://doi.org/10.1093/femsle/fnw244