Metagenomic analysis of mesopelagic Antarctic plankton reveals a novel deltaproteobacterial group

Microbiology (Reading). 2006 Feb;152(Pt 2):505-517. doi: 10.1099/mic.0.28254-0.


Phylogenetic screening of 3200 clones from a metagenomic library of Antarctic mesopelagic picoplankton allowed the identification of two bacterial 16S-rDNA-containing clones belonging to the Deltaproteobacteria, DeepAnt-1F12 and DeepAnt-32C6. These clones were very divergent, forming a monophyletic cluster with the environmental sequence GR-WP33-58 that branched at the base of the myxobacteria. Except for the possession of complete rrn operons without associated tRNA genes, DeepAnt-1F12 and DeepAnt-32C6 were very different in gene content and organization. Gene density was much higher in DeepAnt-32C6, whereas nearly one-third of DeepAnt-1F12 corresponded to intergenic regions. Many of the predicted genes encoded by these metagenomic clones were informational (i.e. involved in replication, transcription, translation and related processes). Despite this, a few putative cases of horizontal gene transfer were detected, including a transposase. DeepAnt-1F12 contained one putative gene encoding a long cysteine-rich protein, probably membrane-bound and Ca2+-binding, with only eukaryotic homologues. DeepAnt-32C6 carried some predicted genes involved in metabolic pathways that suggested this organism may be anaerobic and able to ferment and to degrade complex compounds extracellularly.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antarctic Regions
  • DNA, Bacterial / analysis
  • DNA, Ribosomal / analysis
  • Deltaproteobacteria / enzymology
  • Deltaproteobacteria / genetics*
  • Deltaproteobacteria / growth & development
  • Genome, Bacterial
  • Molecular Sequence Data
  • Plankton
  • RNA, Ribosomal, 16S / analysis
  • RNA, Ribosomal, 16S / genetics


  • DNA, Bacterial
  • DNA, Ribosomal
  • RNA, Ribosomal, 16S

Associated data

  • GENBANK/DQ267495
  • GENBANK/DQ267496