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Following Cell-fate in E. coli After Infection by Phage Lambda
Published on: October 14, 2011
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The plasmid complement of Lactococcus lactis UC509.9 encodes multiple bacteriophage resistance systems
Stuart Ainsworth1, Jennifer Mahony1, Douwe van Sinderen2
1Department of Microbiology, University College Cork, Cork, Ireland.
Applied and Environmental Microbiology
|May 13, 2014
Summary
Lactococcus lactis UC509.9 plasmids were analyzed, revealing four bacteriophage resistance systems. Mutations in the major capsid protein of phage sk1 were linked to AbiB escape mutants, enhancing cheese production understanding.
Area of Science:
- Microbiology
- Dairy Science
- Bacteriology
Background:
- Lactococcus lactis subsp. cremoris is crucial for fermented dairy, especially hard cheeses.
- L. lactis strains adapted to dairy environments via plasmid DNA acquisition, conferring key traits.
- Plasmids carry genes essential for industrial phenotypes in starter cultures.
Purpose of the Study:
- To analyze the eight plasmids of the Irish dairy starter strain L. lactis UC509.9.
- To map key industrial phenotypes and identify genes on these plasmids.
- To investigate the genetic basis of phage resistance in L. lactis UC509.9.
Main Methods:
- Detailed plasmid analysis of L. lactis UC509.9.
- Phenotypic mapping and gene identification.
- Generation and analysis of abortive infection (Abi) escape mutants.
Main Results:
- Eight plasmids were identified in L. lactis UC509.9.
- Four distinct plasmid-borne bacteriophage resistance systems were discovered, including AbiB and AbiD1.
- AbiB escape mutants for phage sk1 showed mutations in orf6, encoding the phage's major capsid protein.
Conclusions:
- The plasmids of L. lactis UC509.9 harbor significant genetic information for dairy applications.
- The identified phage resistance systems contribute to the strain's robustness in dairy fermentations.
- Understanding phage-resistance mechanisms, like AbiB, is vital for preventing phage contamination in industrial settings.
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