Single amino acid mutation in an ATP-binding cassette transporter gene causes resistance to Bt toxin Cry1Ab in the silkworm, Bombyx mori.
Bt toxins derived from the arthropod bacterial pathogen Bacillus thuringiensis are widely used for insect control as insecticides or in transgenic crops. Bt resistance has been found in field populations of several lepidopteran pests and in laboratory strains selected with Bt toxin. Widespread planting of crops expressing Bt toxins has raised concerns about the potential increase of resistance mutations in targeted insects. By using Bombyx mori as a model, we identified a candidate gene for a recessive form of resistance to Cry1Ab toxin on chromosome 15 by positional cloning. BGIBMGA007792-93, which encodes an ATP-binding cassette transporter similar to human multidrug resistance protein 4 and orthologous to genes associated with recessive resistance to Cry1Ac in Heliothis virescens and two other lepidopteran species, was expressed in the midgut. Sequences of 10 susceptible and seven resistant silkworm strains revealed a common tyrosine insertion in an outer loop of the predicted transmembrane structure of resistant alleles. We confirmed the role of this ATP-binding cassette transporter gene in Bt resistance by converting a resistant silkworm strain into a susceptible one by using germline transformation. This study represents a direct demonstration of Bt resistance gene function in insects with the use of transgenesis.
Division of Insect Sciences, National Institute of Agrobiological Sciences, Tsukuba 305-8634, Japan.
Shogo
S
Atsumi
Kazuhisa
K
Miyamoto
Kimiko
K
Yamamoto
Junko
J
Narukawa
Sawako
S
Kawai
Hideki
H
Sezutsu
Isao
I
Kobayashi
Keiro
K
Uchino
Toshiki
T
Tamura
Kazuei
K
Mita
Keiko
K
Kadono-Okuda
Sanae
S
Wada
Kohzo
K
Kanda
Marian R
MR
Goldsmith
Hiroaki
H
Noda
D018528:ATP-Binding Cassette Transporters / Q000737:chemistry / Q000235:genetics*; D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000494:pharmacology*; D012831:Bombyx / Q000235:genetics*; D002874:Chromosome Mapping; D004731:Endotoxins / Q000494:pharmacology*; D008040:Genetic Linkage; D006460:Hemolysin Proteins / Q000494:pharmacology*; D007305:Insecticide Resistance / Q000235:genetics*; D008969:Molecular Sequence Data; D009154:Mutation; D020641:Polymorphism, Single Nucleotide; D017386:Sequence Homology, Amino Acid
D018528:ATP-Binding Cassette Transporters; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis