title: Mis-splicing of the ABCC2 gene linked with Bt toxin resistance in Helicoverpa armigera.
abstract: Toxins from the bacterium Bacillus thuringiensis (Bt) are used widely for insect control in sprays and transgenic plants, but their efficacy is reduced when pests evolve resistance. Previous work showed that mutations in a gene encoding the transporter protein ABCC2 are linked with resistance to Bt toxins Cry1Ab, Cry1Ac or both in four species of Lepidoptera. Here we compared the ABCC2 gene of Helicoverpa armigera (HaABCC2) between susceptible strains and a laboratory-selected strain with >1,000-fold resistance to Cry1Ac relative its susceptible parent strain. We discovered a 73-base pair (bp) insertion in the cDNA of the resistant strain that generates a premature stop codon expected to yield a truncated ABCC2 protein. Sequencing of genomic DNA revealed that this insertion is an intron that is not spliced out because of a 6-bp deletion at its splicing site. Analysis of progeny from crosses revealed tight genetic linkage between HaABCC2 and resistance to Cry1Ac. These results provide the first evidence that mis-splicing of a gene encoding an ABCC2 protein confers resistance to a Bt toxin.
authors.affiliation: The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China.
authors.forename: Yutao
authors.initials: Y
authors.lastname: Xiao
authors.affiliation: The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Zhang
authors.affiliation: The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China.
authors.forename: Chenxi
authors.initials: C
authors.lastname: Liu
authors.affiliation: Department of Entomology, Max Planck Institute for Chemical Ecology, Hans-Knoell-Str. 8, D-07745 Jena, Germany.
authors.forename: David G
authors.initials: DG
authors.lastname: Heckel
authors.affiliation: Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Xianchun
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Entomology, University of Arizona, Tucson, AZ 85721, USA.
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Tabashnik
authors.affiliation: The State Key Laboratory for Biology of Plant Disease and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, West Yuanmingyuan Road, Beijing, 100193, China.
authors.forename: Kongming
authors.initials: K
authors.lastname: Wu
mesh_terms: D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry; D001427:Bacterial Toxins / Q000494:pharmacology*; D001483:Base Sequence; D005260:Female; D008040:Genetic Linkage; D019476:Insect Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*; D007305:Insecticide Resistance; D007306:Insecticides / Q000494:pharmacology*; D007814:Larva / Q000187:drug effects / Q000235:genetics; D007928:Lethal Dose 50; D008297:Male; D008969:Molecular Sequence Data; D009036:Moths / Q000187:drug effects / Q000235:genetics*; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*
chemical_list: D001427:Bacterial Toxins; D019476:Insect Proteins; D007306:Insecticides; D000089762:Multidrug Resistance-Associated Protein 2; D027425:ATP-Binding Cassette, Sub-Family C Proteins