Broadening the insecticidal spectrum of Lepidoptera-specific Bacillus thuringiensis strains by chromosomal integration of cry3A.
A TnpI-TnpIA-mediated and thermosensitive recombination system was developed to construct genetically modified Bacillus thuringiensis strains encoding a crystal protein particularly active against Coleopteran species. Based on B. thuringiensis transposon Tn4430, an integrative vector, pBMB-R14E, was constructed, by which the cry3A delta-endotoxin gene highly toxic to Lepidoptera was delivered into a wildtype B. thuringiensis subsp. kurstaki strain YBT1520. The cry3A gene was integrated into the chromosome of the host strain. Then the integrative vector was eliminated by moving recombinant cultures to 46 degrees C. Two recombinant B. thuringiensis strains, BMB1520-S and BMB1520-T, were obtained. In recombinant strains, the cry3A gene was stably expressed in measurable amounts and did not reduce the expression of endogenous crystal protein genes. Bioassay results showed that BMB1520-S and BMB1520-T, in addition to the activity against lepidopteran Plutella xylostella third-instar larvae present in the parental strains, exhibited a high level of activity against coleopteran Rhyllodecta vulgatissima third-instar larvae, absent from the parental strains.
Yue
Chaoyin
C
Biotechnology Research Center, China Three Gorges University, Yichang, 443002 Hubei, People's Republic of China.
Sun
Ming
M
Yu
Ziniu
Z
D000818:Animals; D001413:Bacillus thuringiensis / Q000235:genetics* / Q000502:physiology; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics*; D001427:Bacterial Toxins / Q000096:biosynthesis / Q000235:genetics*; D002876:Chromosomes, Bacterial / Q000235:genetics; D004251:DNA Transposable Elements; D004731:Endotoxins / Q000096:biosynthesis / Q000235:genetics*; D015870:Gene Expression; D024861:Genetic Enhancement; D005822:Genetic Vectors / Q000235:genetics; D006460:Hemolysin Proteins; D007306:Insecticides; D007814:Larva / Q000382:microbiology; D007915:Lepidoptera / Q000382:microbiology*; D010572:Pest Control, Biological / Q000379:methods*; D010957:Plasmids / Q000235:genetics; D011995:Recombination, Genetic
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004251:DNA Transposable Elements; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; C030956:insecticidal crystal protein, Bacillus Thuringiensis