The LspC3-41I restriction-modification system is the major determinant for genetic manipulations of Lysinibacillus sphaericus C3-41.

LspC3-41I is identified as the major determinant for the restriction barrier of L. sphaericus C3-41. Only three strains of the tested 16 L. sphaericus strains, which all belonging to serotype H5 and ST1 by MLST scheme, contain LspC3-41I system. Two different methods can be used to overcome the restriction barrier of the three isolates to get transformants efficiently: 1) to methylate plasmid DNA prior to the electroporation; and 2) to delete the major restriction endonuclease encoding gene lspC3-41IR.