MICROBIAL PATHOGENESIS, cilt.207, ss.1-9, 2025 (SCI-Expanded)
Ascoviruses are circular double-stranded DNA viruses that infect lepidopterans, producing large enveloped virions
and causing a chronic, deadly disease with apoptosis-like cytopathology. Understanding the codon usage patterns
of ascoviruses could shed light on host-virus interactions, evolutionary pressure, gene expression optimization.
Nevertheless, thorough analyses of codon usage bias (CUB) within the genomes of Ascovirus (a genus in the
Ascoviridae family) have yet to be conducted. Herein, a systematic analysis was performed to clarify the codon usage
patterns in nine viruses of the Ascovirus genus, using their complete genomes. The results revealed a higher
average nucleotide composition for A and T compared to G and C, with a preference for A/T nucleotides, particularly
at the third codon position. Moreover, the results indicated that Ascovirus has a relatively low CUB. Dinucleotide
composition significantly influences the codon usage patterns in Ascovirus. Further analyses, including
ENC plot, neutrality plot, parity rule 2 (PR2) analysis, correspondence analysis, and correlation analysis, confirmed
that mutational pressure had a more significant influence than natural selection in shaping codon usage.
Codon adaptation index (CAI) analysis indicated that Ascovirus is strongly adapted to its hosts. The results of our
study illustrated the codon usage patterns in Ascovirus genomes and provided essential primary data for foundational
evolutionary research on these viruses.