Arch Virol (1997) 142: 333—348
Organization and molecular characterization of genes
in the polyhedrin region of the Anagrapha falcifera
B. A. Federici and R. H. Hice
Department of Entomology and Interdepartmental Graduate Program in Genetics,
University of California, Riverside, California, U.S.A.
Accepted August 8, 1996
Summary. A multinucleocapsid nuclear polyhedrosis virus (MNPV) isolated
from the celery looper, Anagrapha falcifera, has been proposed as a new virus
based on diﬀerences in virulence and DNA fragment proﬁles between this isolate
and the Autographa californica MNPV, the MNPV type species. In the present
study, we examined the relatedness of the AfMNPV and AcMNPV genomes by
(1) Southern hybridization, (2) comparison of their genetic organization in the
polyhedrin gene region (AcMNPV EcoRI-I fragment), and (3) comparison of the
nucleotide and deduced amino acid sequences of eight viral genes in this region.
Both DNAs hybridized strongly to one another in reciprocal hybridization
experiments under stringent conditions, and physical mapping showed that gene
order was conserved between the two viruses in the polyhedrin gene region,
though the ORF 984 and ctl genes were absent from this region in the AfMNPV.
Gene and deduced amino acid sequences for p78, protein tyrosine phospatase,
protein kinase, lef-2, and ORFs 327, 453 and 603, showed identity between the
two viruses of greater than 91%. The sequences for the gp64 gene, located on
a diﬀerent EcoRI fragment, were also compared and had a nucleotide sequence
identity of 97%, and amino acid sequence identity of greater than 98%. The
polyhedrin gene showed the least relatedness between the two viruses, with
a nucleotide sequence identity of 80%, and a deduced amino acid sequence
identity of 90%. Based on these results, we conclude that the AfMNPV should be
considered a variant of the AcMNPV. These results also indicate that caution
must be used in basing phylogenetic relationships of NPVs on analysis of a single
gene, especially the polyhedrin gene, as is the current practice.
Nuclear polyhedrosis viruses (NPVs; Family Baculoviridae, genus Nucleopoly-
hedrovirus) that attack lepidopteran insects comprise the largest known group of