Cloning and expression of delta-endotoxin gene of Bacillus thuringiensis in Escherichia coli.

Fragments (larger than 4 kb) of partially Sau 3AI-digested plasmid DNA from Bacillus thuringiensis subsp. kenyae 7404 and kurstaki HD-1 were cloned into the BamH I site of pBR322. Four transformants, containing the corresponding delta-endotoxin gene and producing proteins that reacted with antiserum against crystalline protein, were selected on the basis of results from in situ colony hybridization, radioimmunologic screening, and Western blot analysis. Three of those tested, i.e., the lysates of one transformant (TK89) carrying the delta-endotoxin gene of B.t. 7404 and two transformants (TH12 and TH48) carrying the delta-endotoxin gene of HD-1, were toxic for tobacco budworm (Heliothis assulta) and armyworm (Leucania separata Walker) caterpillars. This is the first report on cloning of the delta-endotoxin gene from B.t. subsp. kenyae, which is different in serotype from the well-studied subsp. kurstaki.