A novel Tenebrio molitor cadherin is a functional receptor for Bacillus thuringiensis Cry3Aa toxin.
Cry toxins produced by the bacterium Bacillus thuringiensis are effective biological insecticides. Cadherin-like proteins have been reported as functional Cry1A toxin receptors in Lepidoptera. Here we present data that demonstrate that a coleopteran cadherin is a functional Cry3Aa toxin receptor. The Cry3Aa receptor cadherin was cloned from Tenebrio molitor larval midgut mRNA, and the predicted protein, TmCad1, has domain structure and a putative toxin binding region similar to those in lepidopteran cadherin B. thuringiensis receptors. A peptide containing the putative toxin binding region from TmCad1 bound specifically to Cry3Aa and promoted the formation of Cry3Aa toxin oligomers, proposed to be mediators of toxicity in lepidopterans. Injection of TmCad1-specific double-stranded RNA into T. molitor larvae resulted in knockdown of the TmCad1 transcript and conferred resistance to Cry3Aa toxicity. These data demonstrate the functional role of TmCad1 as a Cry3Aa receptor in T. molitor and reveal similarities between the mode of action of Cry toxins in Lepidoptera and Coleoptera.
Fabrick
Jeff
J
United States Department of Agriculture Agricultural Research Service United States Arid-Land Agricultural Research Center, Maricopa, Arizona 85238, USA.
Oppert
Cris
C
Lorenzen
Marcé D
MD
Morris
Kaley
K
Oppert
Brenda
B
Jurat-Fuentes
Juan Luis
JL
D000595:Amino Acid Sequence; D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism* / Q000633:toxicity; D001483:Base Sequence; D015820:Cadherins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D004731:Endotoxins / Q000378:metabolism* / Q000633:toxicity; D006460:Hemolysin Proteins / Q000378:metabolism* / Q000633:toxicity; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000382:microbiology; D008969:Molecular Sequence Data; D010802:Phylogeny; D011485:Protein Binding / Q000502:physiology; D017434:Protein Structure, Tertiary; D034741:RNA, Small Interfering; D013712:Tenebrio / Q000235:genetics* / Q000254:growth & development / Q000382:microbiology
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D015820:Cadherins; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; D034741:RNA, Small Interfering; C030956:insecticidal crystal protein, Bacillus Thuringiensis