Whole genome analysis of Japanese bovine toroviruses reveals natural recombination between porcine and bovine toroviruses

Infect Genet Evol. 2016 Mar:38:90-95. doi: 10.1016/j.meegid.2015.12.013. Epub 2015 Dec 18.


Bovine toroviruses (BToVs), belong to the subfamily Toroviridae within the family Coronaviridae, and are pathogens, causing enteric disease in cattle. In Japan, BToVs are distributed throughout the country and cause gastrointestinal infection of calves and cows. In the present study, complete genome sequences of two Japanese BToVs and partial genome sequences of two Japanese BToVs and one porcine torovirus (PToV) from distant regions in Japan were determined and genetic analyses were performed. Pairwise nucleotide comparison and phylogenetic analyses revealed that Japanese BToVs shared high identity with each other and showed high similarities with BToV Breda1 strain in S, M, and HE coding regions. Japanese BToVs showed high similarities with porcine toroviruses in ORF1a, ORF1b, and N coding regions and the 5' and 3' untranslated regions, suggestive of a natural recombination event. Recombination analyses mapped the putative recombinant breakpoints to the 3' ends of the ORF1b and HE regions. These findings suggest that the interspecies recombinant nature of Japanese BToVs resulted in a closer relationship between BToV Breda1 and PToVs.

Keywords: Bovine torovirus; Japan; Natural recombination; Porcine torovirus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Cattle
  • Cattle Diseases / virology*
  • Genome, Viral*
  • High-Throughput Nucleotide Sequencing
  • Japan
  • Molecular Sequence Data
  • Open Reading Frames
  • Phylogeny
  • Recombination, Genetic*
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Swine / virology*
  • Swine Diseases
  • Torovirus / classification
  • Torovirus / genetics*