Comparative analysis of the genomes of Clostera anastomosis (L.) granulovirus and Clostera anachoreta granulovirus

摘要

Clostera anastomosis (L.) granulovirus (CaLGV) and Clostera anachoreta granulovirus (ClanGV) are both capable of infecting each other's native host insects. Despite this, we have little information on their genetic relationship. The complete nucleotide sequence of CaLGV was determined and compared with that of the genome of ClanGV. The circular, double-stranded DNA CaLGV genome (GenBank accession no. KC179784) had a G+C content of 46.7 % and was 101,818 bp in size (331 bp larger than the ClanGV genome). Overall, the CaLGV nucleotide sequence was found to be 90 % identical to that of ClanGV. It contained a total of 123 ORFs, 119 of which had ClanGV homologues, with an identical transcription direction and ORF organization. Seventy-five of the 119 ORFs showed 90 % or greater identity to their ClanGV homologues. CaLGV contained only a single identifiable homologous region (hrs)/repeat region (similar to ClanGV hr4). The mean frequency of nucleotide substitutions in the CaLGV/ClanGV coding regions was 8.33 %. CaLGV contained four unique ORFs (CaL23, CaL39, CaL48 and CaL92). Eight ORFs found in both CaLGV and ClanGV have no homologues in other baculoviruses. Intergenic regions of CaLGV and ClanGV occupied 6.6 % and 7 % of their respective genomes. CaLGV appears closer phylogenetically to ClanGV than to any other baculoviruses.