Artificial induction of genetic competence in Bacillus amyloliquefaciens isolates.

Abstract

To induce natural genetic competence in Bacillus amyloliquefaciens isolates through overexpression of the master regulator, ComK, from B. subtilis (ComK Bsu ). Plasmid pUBXC carrying the xylose-inducible comK expression cassette was constructed using plasmid pUB110 as a backbone. Plasmid pUBXC could be transferred from B. subtilis to B. amyloliquefaciens through plasmid pLS20-mediated biparental conjugation. After being induced by xylose, four B. amyloliquefaciens strains harbouring plasmid pUBXC developed genetic competence. Under optimal conditions, the transformation efficiencies of plasmid DNA ranged from 129±20.6 to 1.7±0.1×105 cfu (colony-forming units) per μg DNA, and the transformation efficiencies of PCR-assembled deletion constructs ranged from 3.2±0.76 to 3.5±0.42×104cfu per μg DNA in the four tested strains. Artificial induction of genetic competence through overexpressing ComK Bsu in B. amyloliquefaciens completed the tasks of replicative plasmid delivery and gene knockout via direct transformation of PCR-generated deletion cassettes.