The complete genome sequence of the lactic acid bacterium Lactococcus lactis ssp lactis IL1403

Lactococcus lactis is a nonpathogenic AT-rich gram-positive bacterium close ly related to the genus Streptococcus and is the most commonly used cheese starter. It is also the best-characterized lactic acid bacterium. We sequen ced the genome of the laboratory strain IL1403, using a novel two-step stra tegy that comprises diagnostic sequencing of the entire genome and;a shotgu n polishing step. The genome contains 2,365,589 base pairs and encodes 2310 proteins, including 293 protein-coding genes belonging to six prophages an d 43 insertion sequence (IS) elements. Nonrandom distribution of IS element s indicates that the chromosome of the sequenced strain may be a product of recent recombination between two closely related genomes. A complete set o f late competence genes is present, indicating the ability of L. lactis to undergo DNA transformation. Genomic sequence revealed new possibilities for fermentation pathways and for aerobic respiration. It also indicated a hor izontal transfer of genetic information from Lactococcus to gram-negative e nteric bacteria of Salmonella-Escherichia group.