Previous studies have revealed that the protection of restriction-modification system (R-M system) in Bacillus subtilis cells is a major impediment to the transformations of exogenous DNAs through the recognition sites and methyl-modifications. Iin our study, transformations of um-methylized plasmids with no recognition-sites were still improved in constructed strains B.subtilis 168-R- and 168-R-M- with inefficient R-M systems compared with B.subtilis 168. In order to investigate the regulatory mechanism conducted by the R-M system to the plasmids transformtions, host cells during competence-forming stage was explored through comparative transcriptomic analysis to cells under GM2-incubation in the Spizizen method compared with LB-incubation.