Horizontal Transfer of BT Virulence Plasmid among Bacillus cereus sensu lato Population

BT(Bacillus thuringiensis)subsp,kurstaki was taken as a KTO plasmid donor and synaptic transfer hap- pened with Bacillus cereus sensu lato(BCSL)population in liquid conditions.The plasmid stability of the screened synaptic transferee was detected,and proved with PCR,and the chromosomal background of donor and receptor was analyzed with RAPD atlas.Data of plasmid transferring rate in different medium suggested that in artificial LB medium and sterile cow milk plasmid pHT73 could all transfer into BCSL receptor,and the transferring activity of those in cow milk was even higher and reaching 4.8×10~(-4)cfu/donor at the highest.The plasmid receptor bacteria possesses at the same time functions coded by the plasmid,and produces insecticidal crystalline protein that coded.The results of SDS-PAGE electrophoresis and microscopy indicated that after obtaining exogenous plasmid pHT73 the transformant bacteria could produce 130 ku of Cry Ac protein coded by cryl Ac gene,and form stable rhombic crystal during the sporogenesis.