Sequence and gene organization of 24 circles from the Cotesia plutellae bracovirus genome

Twenty-four genomic segments of Cotesia plutellae bracovirus (CpBV) were completely sequenced, and their genomic structures were analyzed. The aggregated genome size is 351,299 bp long and exhibits an average GC content of approximately 34.6%. Average coding density is about 32.3%, and 125 putative open reading frames (ORFs) are predicted. More than half (52.5%) of predicted genes are annotated as hypothetical, but they share sequence similarities with those of other bracoviral genomes. The annotated ORFs can be classified into the known bracoviral families, in which a family of protein tyrosine phosphatase is the largest, including 36 ORFs, suggesting a significant role during parasitization. In addition, 8 and 7 ORFs encode ankyrin-like and EP1-like genes, respectively. Some predicted genes are known only in Cotesia-associated bracoviral genomes. Phylogenetic analyses based on PTP, ankyrin and EP1-like gene groups revealed no correlation between bracoviruses.