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Microparasite manipulation of an insect: the influence of the egt gene on the interaction between a baculovirus and its lepidopteran host
Author(s) -
CORY J. S.,
CLARKE E. E.,
BROWN M. L.,
HAILS R. S.,
O'REILLY D. R.
Publication year - 2004
Publication title -
functional ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.272
H-Index - 154
eISSN - 1365-2435
pISSN - 0269-8463
DOI - 10.1111/j.0269-8463.2004.00853.x
Subject(s) - biology , autographa californica , virus , trichoplusia , pathogen , virology , host (biology) , gene , nuclear polyhedrosis virus , baculoviridae , instar , genetics , insect , microbiology and biotechnology , larva , botany , spodoptera , noctuidae , recombinant dna
Summary1 Parasites and pathogens manipulate their hosts in a variety of ways that are thought to enhance their fitness. However, it is rare to be able to link such phenotypic changes to specific genes. 2 Here the effect of a single pathogen gene is examined. The ecdysteroid UDP‐glucosyltransferase ( egt ) gene of insect baculoviruses produces an enzyme that interferes with host moulting. 3 The effect of the egt gene was examined by comparing two baculoviruses that differed only in the expression of this gene. All three fitness traits examined – pathogenicity, infection duration and pathogen productivity – were affected by deletion of the gene. 4 Trichoplusia ni larvae in all five instars died earlier when infected with the egt ‐minus virus compared with those infected by the wild‐type Autographa californica nucleopolyhedrovirus. 5 Unexpectedly, the egt ‐minus virus was more pathogenic to final instar larvae than the wild‐type virus. Virus genotype and dose both influenced insect development. 6 Wild‐type infected insects had a significantly higher yield of virus at death, cadaver weight and yield of virus per unit weight than those infected with the egt ‐minus virus. 7 The size of the virus challenge had a major influence on the outcome of the interaction. The consequences of these data for pathogen fitness are discussed.