title: Classification, genetic variation and pathogenicity of Lymantria dispar nucleopolyhedrovirus isolates from Asia, Europe, and North America.
abstract: Lymantria dispar multiple nucleopolyhedrovirus (LdMNPV) has been formulated and applied to control outbreaks of the gypsy moth, L. dispar. To classify and determine the degree of genetic variation among isolates of L. dispar NPVs from different parts of the range of the gypsy moth, partial sequences of the lef-8, lef-9, and polh genes were determined for Lymantria spp. virus samples from host populations throughout the world. Sequence analysis confirmed that all L. dispar virus samples tested contained isolates of the species Lymantria dispar multiple nucleopolyhedrovirus (Baculoviridae: Alphabaculovirus). Phylogenetic inference based on the lef-8 sequences indicated that the LdMNPV isolates formed two groups, one consisting primarily of isolates from Asia, and one consisting primarily of isolates from Europe and North America. The complete genome sequence was determined for an isolate from the Asian group, LdMNPV-2161 (S. Korea). The LdMNPV-2161 genome was 163,138bp in length, 2092bp larger than the previously determined genome of LdMNPV isolate 5-6 (CT, USA). The two genome sequences were co-linear, with an overall nucleotide sequence identity of 97.5% and some differences in ORF content. In droplet-feeding bioassays against neonate L. dispar larvae, isolates LdMNPV-3029 (Virin-ENSh/Russia) and LdMNPV-Ab-a624 (MA, USA) killed neonate larvae with an LC50 values that were 1.8- to 3.2-fold lower than a sample of Gypchek® (CT, USA) and isolates LdMNPV-3041 (Japan) and LdMNPV-2161. This study expands our knowledge about genetic variation among LdMNPV isolates and provides novel information on the distinct groups in which these NPVs occur.
authors.affiliation: Invasive Insect Biocontrol and Behavior Laboratory, Beltsville Agricultural Research Center, USDA Agricultural Research Service, 10300 Baltimore Avenue, Beltsville, MD 20705, USA. Electronic address: Robert.L.Harrison@ars.usda.gov.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Harrison
authors.affiliation: Northern Research Station, USDA Forest Service, 51 Mill Pond Road, Hamden, CT 06514, USA. Electronic address: mkeena@fs.fed.us.
authors.forename: Melody A
authors.initials: MA
authors.lastname: Keena
authors.affiliation: Invasive Insect Biocontrol and Behavior Laboratory, Beltsville Agricultural Research Center, USDA Agricultural Research Service, 10300 Baltimore Avenue, Beltsville, MD 20705, USA. Electronic address: Daniel.Rowley@ars.usda.gov.
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Rowley
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001208:Asia; D005060:Europe; D014644:Genetic Variation; D016679:Genome, Viral; D008969:Molecular Sequence Data; D009036:Moths / Q000821:virology*; D009656:North America; D017924:Nucleopolyhedroviruses / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity; D010802:Phylogeny; D016415:Sequence Alignment; D014774:Virulence
keywords: Baculovirus; Genome; Gypsy moth; LdMNPV; Lymantria dispar; Nucleopolyhedrovirus