title: Acquired resistance to a nucleopolyhedrovirus in the smaller tea tortrix Adoxophyes honmai (Lepidoptera: Tortricidae) after selection by serial viral administration.
abstract: A laboratory colony of Adoxophyes honmai was selected for resistance over 156 generations by feeding neonate larvae of every generation with the LC60or LC70of its nucleopolyhedrovirus, Adoxophyes honmai nucleopolyhedrovirus (AdhoNPV). A significant difference in LC50values between the selected (R-strain) and unselected (S1- and S2-strain) strains was first observed after three generations of selection, and the resistance level then increased continuously. The highest degree of acquired resistance, based on the ratio of the LC50values of R- and S1-strains, was more than 400,000-fold. After selection was stopped at either the 21st or the 149th generation, LC50values did not decrease significantly, suggesting that resistance of the R-strain to AdhoNPV was stable. To assess which of the two routes of baculovirus infection is affected by resistance to AdhoNPV, 5th instar larvae of the R-strain were inoculated orally and intrahemocoelically with AdhoNPV and their susceptibility was compared to that of S-strain. The ratio of the LC25values of selected and unselected strains was 91-fold when budded viruses were injected into 5th instar larvae, but was 107,000-fold after oral inoculation. These results indicate that the resistance mechanism of the R-strain of A. honmai disrupts both midgut primary infection and hemocoelic secondary infection.
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan. Electronic address: madoka@cc.tuat.ac.jp.
authors.forename: Madoka
authors.initials: M
authors.lastname: Nakai
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Takahashi
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Kento
authors.initials: K
authors.lastname: Iwata
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Junko
authors.initials: J
authors.lastname: Koyanagi
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Akemi
authors.initials: A
authors.lastname: Ookuma
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Takatsuka
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Shohei
authors.initials: S
authors.lastname: Okuno
authors.affiliation: Institute of Agriculture, Tokyo University of Agriculture and Technology, Saiwai, Fuchu, Tokyo 183-8509, Japan.
authors.forename: Yasuhisa
authors.initials: Y
authors.lastname: Kunimi
mesh_terms: D000818:Animals; D060467:Disease Resistance / Q000502:physiology*; D007915:Lepidoptera / Q000276:immunology* / Q000821:virology*; D017924:Nucleopolyhedroviruses
keywords: Adoxophyes honmai; Baculovirus; Nucleopolyhedrovirus; Resistance