Complete Genome Sequence Analysis Of Anagrapha Falcifera Nucleopolyhe-Drovirus

The celery looper(Lepidoptera:Noctuidae)is a harmful agri-cultural pest that causes severe damages to a wide range of crops and vegetables,Ana-grapha falcifera nucleopolyhedrovirus(AnfaNPV)is a pathogen and an ecological con-trol factor of the pest.Previously,AnfaNPV was shown to be closely related toα-baculoviruses Rachiplusia ou multiple nucleopolyhedrovirus(RaouNPV),Autographa californica multiple nucleopolyhedrovirus(AcMNPV)and Plutella xylostella multiple nucleopolyhedrovirus(PlxyMNPV).In this study,the complete genome of AnfaNPV was sequenced and analyzed to provide basic data for understanding the genetic characteris-tics and application of the virus.The viral occlusion bodies were isolated and purified from the rot tissue of the beet armyworm larvae killed by AnfaNPV infection by differential centrifugation,and the DNA was purified from the viral occlusion bodies by alkaline cracking,protease K treatment,phenol-chloroform extraction,and ethanol precipitation,gradually.Based on the RaouNPV genome sequence,108 pairs of PCR primers were synthesized.The puri-fied AnfaNPV DNA was used as a template to amplify DNA fragments with an average length of about 1900 BP,and the sequencing was completed using the ABI system;Using the Geneious Prime 2019.1 software,187 read-order sequences of 200-900 nt were ob-tained and assembled into a complete genome sequence.The genome of AnfaNPV has a double-stranded DNA of 133258bp in length with a G+C content of 39.96%and contained 150 non-overlapping opening reading frames(ORFs)encoding predicted proteins of over 50 amino acid residues in size.Nine homol-ogous repeating regions(hrs)were identified,consisting of a variable number of 30bp imperfect palindromic sequences.The AnfaNPV genome contained the 38 core genes of the Baculoviridae family,and all of its ORFs had homologous genes from other bacu-loviruses.There was not any ORF unique to AnfaNPV.Af95 only has a single homolog,ac97.Gene polarity plots showed that AnfaNPV genome was perfectly collinear with Ra-ouMNPV,AcMNPV,and PlxyMNPV genomes.The AnfaNPV genome is 1732bp more than RaouMNPV,636bp and 1159bp less than AcMNPV and PlxyMNPV,respectively.The sequence similarities between the AnfaNPV genome and the RaouMNPV,AcMNPV and PlxyMNPV genomes were 97.34%,97.05%and 96.32%,respectively.145 ORFs are common to these four baculoviruses.The number of ORFs with identical codons be-tween AnfaNPV and RaouMNPV,AcMNPV and PlxyMNPV were 46,42 and 23,respec-tively.Phylogenetic analysis based on 34 core genes of baculoviruses demonstrated that AnfaNPV belonged to α-baculoviruses group I,being most close to RaouMNPV.