Transformation of Bacillus subtilis, antifungal-antibiotic iturin producers with isolated antibiotic resistance plasmids

In order to obtain appropriate vectors to transform several strains of Bacillus subtilis, antifungal iturin producers, plasmids have been isolated as covalently closed circular deoxyribonucleic acid from antibiotic-resistant bacteria inhabited in composts. Eight plasmids coding antibiotic resistance transformed both competent cells of a derivative of B. subtilis Marburg 168 and protoplasts of B. subtilis NB22, an antifungal-antibiotic iturin producer, in the presence of polyethylene glycol. However, transformation efficiency was not high enough as a cloning host-vector system. To improve transformation efficiency, KCl-treatment method and electroporation method were applied to four iturin producers, and electroporation method was most effective for transformation with newly-isolated plasmids with great efficiency.