Artificial induction of genetic competence in Bacillus amyloliquefaciens isolates

Objectives

To induce natural genetic competence in Bacillus amyloliquefaciens isolates through overexpression of the master regulator, ComK, from B. subtilis (ComK _Bsu ).

Results

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 × 10⁴ cfu per μg DNA in the four tested strains.

Conclusion

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.