Natural competence-deficient mutant of Bacillus subtilis BR151, which carries plasmid pUB110, was obtained by nitrosoguanidine mutagenesis on solid medium.

• 以携带pUB110质粒的枯草芽孢杆菌BR151菌株为出发菌株，利用亚硝基胍作诱变剂，直接在LB平板上进行诱变。