Group II nucleopolyhedrovirus subgroups revealed by phylogenetic analysis of polyhedrin and DNA polymerase gene sequences

Two major clades, designated Groups I and II, of nucleopolyhedroviruses (NP Vs) from lepidopteran hosts have been previously identified. To reveal more detailed relationships, a series of DNA polymerase nucleotide sequences fr om the taxa MbMNPV, SeMNPV, HzSNPV, HearNPV, SpltNPV, BusuNPV, and OranNPV have been determined using a polymerase chain reaction (PCR)-based approach . This technique enabled gene sequence determination using microliter sampl es of NPV-infected insect cadavers. Polyhedrin genes from HearNPV, OranNPV, SeMNPV, and SpltNPV were also isolated and sequenced using a similar appro ach. These sequences, together with other database entries, were aligned fo r positional homology of peptide sequences. Phylogenetic analysis of DNA po lymerase molecular sequence alignments supports LdMNPV as a taxon of Group II and three Group II subclades, designated A, B, and C. Comparison of DNA polymerase trees with those estimated from occlusion protein molecular sequ ences enabled identification of three subclades of Group II. These are Subg roup II-A [MbMNPV, LeseNPV, MacoNPV, PaflNPV, SeMNPV, SpltNPV (India isolat e), SfMNPV]; Subgroup II-B [SpliNPV, SpltNPV (Japan isolate), SpltNPV (Quee nsland isolate), and possibly HzSNPV, HearNPV, and ManeNPV], and Subgroup I I-C [OpSNPV, OranNPV (S-type), BusuNPV (S-type), and possibly EcobNPV (S-ty pe)]. Notably, all Subgroup II-A taxa are from noctuid hosts. Correlations of virus and host evolution within Group II taxa are discussed. The methods and data developed in this study will allow rapid sequencing of NPV DNA po lymerase genes. (C) 1999 Academic Press.