The complete genome sequence of the lactic acid bacterium Lactococcus lactis.
Alexander Bolotin*, Patrick Winckers§, Stephane Mauger*, Olivier Jaillon§, Karine Malarm*, Jean Weissenbach§, S. Dusko Ehrlich* and Alexei Sorokin*
Lactococcus lactis is a nonpathogenic AT-rich gram-positive bacterium closely related to the genus Streptococci and is the most commonly used cheese starter. It is also the best-characterized lactic acid bacterium. We sequenced the genome of the laboratory strain IL1403, using a novel two-step strategy that comprises diagnostic sequencing of the entire genome and a shotgun-polishing step. The genome contains 2,365,589 base pairs, and encodes 2,310 proteins, including 293 protein-coding genes for six prophages and 43 IS elements. Nonrandom distribution of IS elements indicates that the chromosome of the sequenced strain may be a product of recent recombination between two closely related genomes. It contains a complete set of late competence genes, indicating the ability to undergo DNA transformation. Genomic sequence revealed new possibilities for fermentation pathways and for aerobic respiration. It also indicated a horizontal transfer of genetic information from Lactococci to gram-negative enteric bacteria of Salmonella-Escherichia group.
