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Bacillus thuringiensis isolates from the Philippines: habitat distribution, delta-endotoxin diversity, and toxicity to rice stem borers (Lepidoptera: Pyralidae)

  • Author(s) / Creator(s)
  • Abstract: Bacillus thuringiensis Berliner isolates were detected in 57% of 801 samples of rice grain dust, soil, rice field arthropods, and miscellaneous habitats (rice straw compost and mammal faeces) collected at 100 sites in the Philippines. The collection yielded 3950 isolates of B. thuringiensis (8.7 isolates/positive sample). Grain dust from rice mills was the richest source (63% of the samples were positive, with 10.2 isolates/positive sample), followed by rice field arthropods, soil, and miscellaneous habitats. Polyclonal antibodies to six delta-endotoxin groups (Cry1A, Cry1B, Cry1C, Cry1D, Cry1E, and Cry3A) were used in enzyme-linked immunosorbent assays (ELISA) to characterize the toxins produced by each isolate. Subsamples of isolates representing the diversity of isolate sources and delta-endotoxin profiles were bioassayed against the yellow stem borer, Scirpophaga incertulas (Walker) and striped stem borer, Chile suppressalis (Walker). Eighteen isolates highly toxic to both species were selected for characterization of delta-endotoxin genes by polymerase chain reaction (PCR) with primers specific to 14 genes or gene subfamilies, and Western blotting with Cry2A antibodies. At least two novel delta-endotoxin genes, related to cry1B and cry1F, were detected by DNA sequencing of PCR products.

  • Date created
    1998
  • Subjects / Keywords
  • Type of Item
    Article (Published)
  • DOI
    https://doi.org/10.7939/R38G8FK3N
  • License
    © 1998 Cambridge University Press. This version of this article is open access and can be downloaded and shared. The original author(s) and source must be cited.
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  • Citation for previous publication
    • Theunis W, Aguda RM, Cruz WT, Decock C, Peferoen M, Lambert B, Bottrell DG, Gould FL, Litsinger JA, Cohen MB. (1998). Bacillus thuringiensis isolates from the Philippines: habitat distribution, delta-endotoxin diversity, and toxicity to rice stem borers (Lepidoptera: Pyralidae). Bulletin of Entomological Research 88:335-42.