Development of bacteriophage resistant starter cultures - genetic engineering vs. classical methods

摘要

Infections with bacteriophages are still a major problem during dairy fermentations. A possible way to solve this problem is the introduction of phage insensitive starter cultures. However, due to strict legislative regulations and lack of consumer acceptance in Europe the improvement of phage resistance by genetic engineering is problematic. Here we describe three different possibilities to generate phage insensitive mutants with different degrees of using genetic tools: 1. Genetic engineering resulting in a GMO: inactivation of pip gene. 2. Spontaneous mutant selection resulting in nonGMO variants: screening for spontaneous phage resistant mutants towards c2-type phages. 3. Combination of genetic engineering tools with a classical method resulting in a new variant: introduction of a marker plasmid by electroporation, conjugative transfer of phage resistance plasmids and successive curing of the marker plasmid.