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Title: EVALUATION OF BACILLUS THURINGIENSIS STRAINS FOR CRY TOXINS EFFECTIVE IN CONTROLLING THE RICE INSECT PESTS

Author
item Rice, William

Submitted to: Rice Technical Working Group Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/1/1997
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Bacillus thuringiensis strains have been used to develop a number of biopesticides, which have been used to protect agronomically important crops. A number of agronomically important crops face severe pressure from a variety of insect pests. For instance rice is exposed to intense insect pressure from Coleopteran and Lepidopteran pests. In addition toxin genes from these biopesticides can serve as a source of insecticidal genes for the development of enhanced germplasm conferring resistance to injurious insects. Methods to rapidly identify and classify insect specific toxin genes (Cry toxins from B. thuringiensis) would facilitate their implementation and use in crop protection. Recent approaches to the characterization of novel isolates involve the use of the Polymerase Chain Reaction (PCR) to rapidly identify and classify Cry toxins based on the presence of diagnostic fragments when employing specific classes of oligonucleotide primers. We have extended this approach using existing primers and have developed new primers for the rapid detection of potentially new and useful insecticidal genes from Bacillus thuringiensis strains. New primers for the detection of Vip3A(a) and Vip3A(b) insecticidal genes were developed. B. thuringiensis strains were identified that contain different gene-toxin combinations. Field trials were conducted utilizing B. thuringiensis isolates that contain different toxin combinations in order to value their potential for controlling RWW larval populations. Several B. thuringiensis strains caused a reduction in RWW larval numbers. Immunological methods to facilitate the identification and monitor the expression of B. thuringiensis toxin proteins were also developed. Factors relative to the implementation of B. thuringiensis gene