New single-stranded DNA virus with a unique genomic structure that infects marine diatom Chaetoceros setoensis

Sci Rep. 2013 Nov 26:3:3337. doi: 10.1038/srep03337.


Diatoms are among the most abundant organisms in nature; however, their relationships with single-stranded DNA (ssDNA) viruses have not yet been defined in detail. We report the isolation and characterisation of a virus (CsetDNAV) that lytically infects the bloom-forming diatom Chaetoceros setoensis. The virion is 33 nm in diameter and accumulates in the nucleus of its host. CsetDNAV harbours a covalently closed-circular ssDNA genome comprising 5836 nucleotides and eight different short-complementary fragments (67-145 nucleotides), which have not been reported in other diatom viruses. Phylogenetic analysis based on the putative replicase-related protein showed that CsetDNAV was not included in the monophyly of the recently established genus Bacilladnavirus. This discovery of CsetDNAV, which harbours a genome with a structure that is unique among known viruses that infect diatoms, suggests that other such undiscovered viruses possess diverse genomic architectures.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • DNA Viruses / genetics*
  • DNA Viruses / isolation & purification
  • DNA Viruses / pathogenicity
  • DNA, Circular / genetics
  • DNA, Single-Stranded / genetics
  • DNA, Viral / genetics*
  • Diatoms / virology*
  • Genome, Viral / genetics*
  • Phylogeny
  • Sequence Analysis, DNA
  • Viral Proteins / genetics*
  • Virus Assembly / physiology
  • Virus Replication / physiology


  • DNA, Circular
  • DNA, Single-Stranded
  • DNA, Viral
  • Viral Proteins