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  • 2019-Red Sea SAR11

    Accepted author manuscript, 1 MB, PDF-document

    Embargo ends: 17/12/19

DOI

  • Luke R. Thompson
    King Abdullah University of Science and Technology, Saudi Arabia
  • Mohamed F. Haroon
  • Ahmed A. Shibl
  • Matt J. Cahill
  • David K. Ngugi
  • Gareth J. Williams
  • James T. Morton
  • Rob Knight
    University of California, San Diego
  • Kelly D. Goodwin
  • Ulrich Stingl
    King Abdullah University of Science and Technology, Saudi Arabia
Evidence suggests many marine bacteria are cosmopolitan, with widespread but sparse strains poised to seed abundant populations upon conducive growth conditions. However, studies supporting this 'microbial seed bank' hypothesis have analyzed taxonomic marker genes rather than whole genomes/metagenomes, leaving open the possibility that disparate ocean regions harbor endemic gene content. The Red Sea is isolated geographically from the rest of the ocean and has a combination of high irradiance, high temperature, and high salinity that is unique among the ocean; we therefore asked whether it harbors endemic gene content. We sequenced and assembled single-cell genomes of 21 SAR11 (subclades Ia, Ib, Id, II) and 5 Prochlorococcus (ecotype HLII) cells from the Red Sea and combined them with globally-sourced reference genomes to cluster genes into ortholog groups (OGs). Ordination of OG composition could distinguish clades, including phylogenetically cryptic Prochlorococcus ecotypes LLII and LLIII. Compared with reference genomes, 1% of Prochlorococcus and 17% of SAR11 OGs were unique to the Red Sea genomes (RS-OGs). Most (83%) RS-OGs had no annotated function, but 65% of RS-OGs were expressed in diel Red Sea metatranscriptomes, suggesting they could be functional. Searching Tara Oceans metagenomes, RS-OGs were as likely to be found as non-RS-OGs; nevertheless, Red Sea and other warm samples could be distinguished from cooler samples using the relative abundances of OGs. The results suggest that the prevalence of OGs in these surface ocean bacteria is largely cosmopolitan, with differences in population metagenomes manifested by differences in relative abundance rather than complete presence-absence of OGs
Original languageEnglish
Article numbere00369-19
JournalApplied and Environmental Microbiology
Volume85
Issue number13
Early online date17 Jun 2019
DOIs
Publication statusPublished - Jul 2019
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