ABSTRACT
This paper reports the optimized electro-transformation parameters of Bacillus thuringiensis plasmid-free mutant strain BMB171 by electroporation, and expressing effect of several cry genes introduced in this recipient. It showed that a highest electro-transformation frequency could be obtained, when SG solution was used as the buffer, and a 10.0V/cm of field strength, one time of pulse as well as a growth phase of recipient cells at the exponential phase (OD650nm value was 0.2~0.3) were selected. The highest of electro-transformation frequency with pHT3101 could reach at 8 ?107 hansformants/?g DNA. The transformation frequencies increased at linear velocity as the concentration increase of pHT3101 from 54.69pg/ml to 3.50?g/mL, then reached saturation afterwards. All plasmids introduced in BMB171 could produce characteristic insecticidal crystal proteins through expression of relevent cry genes carried by them. Meanwhile, these insecticidal crystal proteins could form parasporal crystals, which have characteristic geometric shapes.