Shuttle Vectors of Bacillus thuringiensis

Abstract

Bacillus thuringiensis is characterized by the synthesis of parasporal crystals during sporulation; these are composed of one or more highly specific insecticidal or nematocidal endotoxin proteins. Genetic manipulation of B. thuringiensis has been achieved due to the development of stable shuttle vectors and the establishment of efficient transformation systems. Shuttle vectors of B. thuringiensis have been constructed using essentially replicons from resident plasmids from this bacterium that replicate by the theta mechanism. Also, these vectors have been developed using plasmid replicons from other Gram-positive bacteria or RCR plasmids. The transformation of B. thuringiensis with these vectors has been accomplished mainly through electroporation. The development of shuttle vectors with better characteristics and protocols with high transformation efficiency have greatly facilitated basic research and engineering of B. thuringiensis.