Complete Sequences of Four Plasmids ofLactococcus lactissubsp.cremorisSK11 Reveal Extensive Adaptation to the Dairy Environment
- 1 December 2005
- journal article
- research article
- Published by American Society for Microbiology in Applied and Environmental Microbiology
- Vol. 71 (12), 8371-8382
- https://doi.org/10.1128/aem.71.12.8371-8382.2005
Abstract
Lactococcus lactis strains are known to carry plasmids encoding industrially important traits. L. lactis subsp. cremoris SK11 is widely used by the dairy industry in cheese making. Its complete plasmid complement was sequenced and found to contain the plasmids pSK11A (10,372 bp), pSK11B (13,332 bp), pSK11L (47,165 bp), and pSK11P (75,814 bp). Six highly homologous repB-containing replicons were found, all belonging to the family of lactococcal theta-type replicons. Twenty-three complete insertion sequence elements segment the plasmids into numerous modules, many of which can be identified as functional units or containing functionally related genes. Plasmid-encoded functions previously known to reside on L. lactis SK11 plasmids were now mapped in detail, e.g., lactose utilization (lacR-lacABCDFEGX), the proteolytic system (prtM-prtP, pepO, pepF), and the oligopeptide permease system (oppDFBCA). Newly identified plasmid-encoded functions could facilitate the uptake of various cations, while the pabA and pabB genes could be essential for folate biosynthesis. A competitive advantage could be obtained by using the putative flavin adenine dinucleotide-dependent d-lactate dehydrogenase and oxalate:formate antiporter for enhanced ATP synthesis, while the activity of the predicted α-acetolactate decarboxylase may contribute to the formation of an additional electron sink. Various stress response proteins are plasmid encoded, which could enhance strain robustness. A substantial number of these “adaptation” genes have not been described before on L. lactis plasmids. Moreover, several genes were identified for the first time in L. lactis, possibly reflecting horizontal gene transfer.Keywords
This publication has 88 references indexed in Scilit:
- Complete sequence and comparative genome analysis of the dairy bacterium Streptococcus thermophilusNature Biotechnology, 2004
- The Pfam protein families databaseNucleic Acids Research, 2004
- IS 981 -Mediated Adaptive Evolution Recovers Lactate Production by ldhB Transcription Activation in a Lactate Dehydrogenase-Deficient Strain of Lactococcus lactisJournal of Bacteriology, 2003
- The CorA Magnesium Transporter Gene FamilyMicrobial & Comparative Genomics, 1998
- Gapped BLAST and PSI-BLAST: a new generation of protein database search programsNucleic Acids Research, 1997
- DNA sequence of recombinase‐binding sites can determine Xer site‐specific recombination outcomeMolecular Microbiology, 1997
- Theta replication of the lactococcal plasmid pWVO2Molecular Microbiology, 1993
- Molecular and functional characterization of a carbon starvation gene of Escherichia coliJournal of Molecular Biology, 1991
- Cloning of usp45, a gene encoding a secreted protein from Lactococcus lactis subsp. lactis MG1363Gene, 1990
- Plasmid encoded bacteriophage resistance inStreptococcus cremorisSK11FEMS Microbiology Letters, 1984