ABSTRACT
Extensive screening programs have been carried out worldwide to search for a Bacillus thuringiensis (Bt) strain with a new insecticidal spectrum, and recent advances in recombinant DNA technology have now made it more feasible to use Bt for pest control. The technology has enabled the cloning of insecticidal protein genes and their expression in heterologous host cells, thereby providing novel production and delivery systems for these proteins. This chapter reviews genetic engineering on Bt, and the potential of recombinant DNA technology for improving the effectiveness and usefulness of Bt-based insecticides. In this system, an insecticidal protein gene is introduced and expressed in P. fluorescence cells. Conjugal transfer of the plasmids was used to construct Bt strains with improved insecticidal activities, and these have been employed as the active ingredients of commercial Bt-based insecticides. An efficient transformation system for Bt has been recently developed by employing electroporation.
