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Bacillus thuringiensis cry3Ca1 Protein Is Toxic to the Colorado Potato Beetle, Leptinotarsa decemlineata (Say)
Author(s) -
Haffani Yosr Z.,
Cloutier Conrad,
Belzile François J.
Publication year - 2001
Publication title -
biotechnology progress
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.572
H-Index - 129
eISSN - 1520-6033
pISSN - 8756-7938
DOI - 10.1021/bp000150d
Subject(s) - leptinotarsa , bacillus thuringiensis , colorado potato beetle , biology , instar , larva , pest analysis , bioassay , insect , escherichia coli , bacillales , microbiology and biotechnology , toxicology , botany , bacteria , ecology , gene , biochemistry , bacillus subtilis , genetics
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 δ‐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.