Sequencing of the Bacillus thuringiensis plasmid genome

Bacillus thuringiensis has cry genes, which encode the δ-endotoxins, with activity for insect larvae of agricultural and health interest. The toxins are located in high molecular mass conjugative plasmids, which replicate with low copy number and have remarkable segregational stability. Although B. thuringiensis is the most widely used microorganism in biological pest control, it is always necessary to screen for new cry genes to combat new insects or replace Cry proteins to avoid insect resistance. Complete sequencing of the plasmids will provide information on cry gene sequences and possible operons and regulatory sequences.