Genomic Analysis Of Heliothis Virescens Ascovirus 3f Isolated From Helicoverpa Zea

Ascovirus is the only genus recognized in the family Ascoviridae with double-stranded circular DNA genomes. They can cause a chronic but ultimately fatal disease in the larvae of Lepidoptera, Hymenoptera and Coleoptera. With the development of structural genomics, comparative genomics and bioinformatics, as well as the availability to a large number of ascovirus whole genomes. The species HvAV-3a is the most diverse and widely distributed. HvAV-3f genomic sequences of the first HvAV-3a isolate from America was sequenced. This study explored the nucleotide and codon and comparative genomics analysis among ascovirus genomes.HvAV-3f genomic DNA was sequenced by the Solexa genome analyzer at the Beijing Genome Institution, Shenzhen, China (BGI). A total of 6,244,397 clean pair-end (PE) reads were obtained. Genome assembly was performed using the Edena and Abyss assembly software package. ORFs were identified through the GeneMarkS program, ORF finder (NCBI) and Geneious program. The HvAV-3f genome has a circular genome of 198,157 bp with a G+C content of 46.0%. The sequences were deposited in NCBI's GenBank with the accession number KJ755191.The HvAV-3f genome encodes 190 open reading frames (ORFs), in which 107 are in the forward orientation and 83 in the reverse. The coding region 108 (166,217 bp) accounted for 83.88% of the total sequences. Two major homologous regions (hrs),29'baculovirus repeat ORFs'(bro) and 5 iap-like gene were found in the genome. BLAST analyses revealed that three HvAV-3f genes were homologous to that of lepidopteran insects. Nine ORFs were unique to HvAV-3f. Twenty-five genes encoding for enzymes involved in gene transcription, DNA replication, and nucleotide metabolism were found in the Hv A V-3f genome.By Codon Composition, Relative Synonymous Codon Usage, Codon Adaptation Index, Dinucleotide Relative Abundance, Effective Number of Codon and correspondence analysis to reveal characterization of codon usage of HvAV-3f. It showed that the preferred synonymous codons were G/C. In addition, probably affected by its hosts.