Bacillus thuringiensis cry3Ca1 protein is toxic to the Colorado potato beetle, Leptinotarsa decemlineata (Say).
We expressed the wild-type cry3Aa3 and cry3Ca1 Bacillus thuringiensis genes, which code for insecticidal proteins, in an Escherichia coli expression system. Highly purified preparations of the soluble delta-endotoxins were used to perform comparative bioassays with third-instar larvae of the Colorado potato beetle (CPB). Acute mortality data showed that Cry3Ca1 (LD(50) = 320.1 ng) was 2-fold more toxic than Cry3Aa3 (LD(50) = 672.9 ng). We also compared the chronic effects of sublethal doses of these toxins by measuring the consumption of untreated foliage and monitoring survival and development for 6 days after intoxication. No significant additional mortality was recorded, but we found that surviving larvae fed Cry3Ca1 consumed foliage at a slower rate than the larvae fed Cry3Aa3, suggesting more damage to their digestive epithelium. This study, the first assessment of the toxicity of cry3Ca1 in third-instar CPB, suggests cry3Ca1 will prove useful for the control of this important insect pest.
Haffani
Y Z
YZ
Département de Phytologie, Pavillon C. E. Marchand, and Département de Biologie, Pavillon Vachon, Université Laval, Sainte-Foy, Québec G1K 7P4, Canada.
Cloutier
C
C
Belzile
F J
FJ
D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000633:toxicity*; D001427:Bacterial Toxins; D001483:Base Sequence; D003001:Cloning, Molecular; D001517:Coleoptera / Q000254:growth & development; D017931:DNA Primers; D004591:Electrophoresis, Polyacrylamide Gel; D004731:Endotoxins / Q000235:genetics / Q000302:isolation & purification / Q000633:toxicity*; D004926:Escherichia coli / Q000235:genetics; D006460:Hemolysin Proteins; D007814:Larva / Q000187:drug effects / Q000254:growth & development; D007928:Lethal Dose 50; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000302:isolation & purification / Q000633:toxicity
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D017931:DNA Primers; D004731:Endotoxins; D006460:Hemolysin Proteins; D011993:Recombinant Fusion Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis