Induction of Loci Mutation during Lactococcus lactis Spontaneous Conversion to Bacteriophage-Insensitive Phenotype

Abstract

The dairy industry utilizes Lactococcus lactis strains as starter cultures to manufacture fermented products. Bacteriophages specific for the cultures are an important and persistent problem for the industry. The development of phage-insensitive strains is one approach to handle the problem. We have identified loci that were spontaneously mutated in Lactococcus lactis ssp. cremoris MG1363 during its natural conversion to the phage-resistant phenotype as a challenge to sk1 phage. Whole genome analysis by PCR fingerprinting technique pinpointed genes encoding proteins involved in cell wall metabolism, transmembrane and membrane associated proteins, transcriptional regulators, prophage components, and enzymes of basal metabolism.

Keywords:

• mutation
• spontaneous
• phage
• sk1
• Lactococcus lactis

ACKNOWLEDGMENTS

We are grateful to Prof. Todd R. Klaenhammer for his generous gift of L. lactis MG1363 and sk1 phage.