Development of a BtBooster Synergist for Bt Transgenic Plants

Insecticidal efficacy is a major insecticide market driver. In 2004, InsectiGen, Inc. announced a scientific breakthrough, BtBooster, a new technology that enhances the performance of the leading biopesticide, Bacillus thuringiensis (Bt). Although extended efforts to improve Bt biopesticides have led to the discovery of over 250 cry genes, only a few are deployed in Bt plants. BtBooster is a peptide obtained from a cadherin of Manduca sexta (tobacco hornworm) and has no known or predicted toxicity to living organisms. It also has no homology to known allergens. Yet BtBooster can synergize the potency of Bt toxins and has potential as an additive to current Bt crops. Previous research results demonstrated that two early forms of BtBooster could enhance Bt toxicity and could also partially overcome Bt resistance in a Bt-resistant strain of Plutella xylostella (diamondback moth). The commercially relevant biotechnical hypothesis behind this project is that co-expression of Bt and BtBooster together or in separate cellular compartments in transgenic plants will produce substantial increases in insect mortality relative to toxin expression alone. In this proposal, we will examine expression of Cry1Ac and a new protease-stabilized form of BtBooster together in the cytoplasm and separately in the cytoplasmic and apoplastic compartments in a model plant species to find the optimal Bt/BtBooster co-expression pattern. The goal is to demonstrate enhanced efficacy of co-expression of Bt and BtBooster within a model plant. We envision it will broaden opportunities for Bt-based insect control by overcoming Bt expression limitations in Bt crops.