Previous Article | Next Article ![]()
J Virol, March 1998, p. 2526-2531, Vol. 72, No. 3
Program in Genetics,1
Departments of Entomology2 and
Microbiology,5 and
Pesticide
Research Center,3 Michigan State University,
East Lansing, Michigan 48224-1115, and
Agricultural Research
Division, American Cyanamid, Princeton, New Jersey
08543-04004
Received 14 July 1997/Accepted 4 December 1997
The gypsy moth (Lymantria dispar) is nonpermissive for
Autographa californica nucleopolyhedrovirus (AcNPV)
infection. We previously isolated a gene, host range factor 1 (hrf-1), from L. dispar nucleopolyhedrovirus that promotes AcNPV replication in Ld652Y cells, a nonpermissive L. dispar cell line (S. M. Thiem, X. Du, M. E. Quentin, and M. M. Berner, J. Virol. 70:2221-2229, 1996). In
the present study, we investigated the ability of hrf-1 to
alter the larval host range of AcNPV. Bioassays using recombinant AcNPV
bearing hrf-1 were conducted with insect larvae by use of
oral infection. AcNPV bearing hrf-1 was infectious for
neonate L. dispar larvae, with a 50% lethal concentration
of 1.2 × 105 polyhedral inclusion bodies/ml of diet,
which is similar to that of wild-type AcNPV for permissive hosts. AcNPV
can kill neonate L. dispar larvae at high doses, but it
does not kill third-instar larvae. However, electron microscopy studies
of AcNPV-inoculated third-instar larvae revealed virus replication in
the midgut cells. PCR analyses indicated that the virus was AcNPV.
These results suggest that the block for AcNPV infection of L. dispar larvae is its inability to spread systematically from
primary infection sites in the midgut epithelium and that this barrier
is leaky in neonates. hrf-1 allows AcNPV to overcome this
barrier. AcNPV recombinants bearing hrf-1 were also
significantly more infectious for Helicoverpa zea, a
resistant species, suggesting that the blocks for AcNPV infection of
L. dispar and H. zea larvae may be similar.
0022-538X/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.
Lymantria dispar Nucleopolyhedrovirus
hrf-1 Expands the Larval Host Range of Autographa
californica Nucleopolyhedrovirus

*
Corresponding author. Mailing address: Department of
Entomology, 243 Natural Science, Michigan State University, East
Lansing, MI 48824-1115. Phone: (517) 432-1713. Fax: (517) 353-5598. E-mail: smthiem{at}pilot.msu.edu.
Present address: The Wistar Institute, Philadelphia, PA 19104.
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»