title: The complete genome sequence of Lactobacillus bulgaricus reveals extensive and ongoing reductive evolution.
abstract: Lactobacillus delbrueckii ssp. bulgaricus (L. bulgaricus) is a representative of the group of lactic acid-producing bacteria, mainly known for its worldwide application in yogurt production. The genome sequence of this bacterium has been determined and shows the signs of ongoing specialization, with a substantial number of pseudogenes and incomplete metabolic pathways and relatively few regulatory functions. Several unique features of the L. bulgaricus genome support the hypothesis that the genome is in a phase of rapid evolution. (i) Exceptionally high numbers of rRNA and tRNA genes with regard to genome size may indicate that the L. bulgaricus genome has known a recent phase of important size reduction, in agreement with the observed high frequency of gene inactivation and elimination; (ii) a much higher GC content at codon position 3 than expected on the basis of the overall GC content suggests that the composition of the genome is evolving toward a higher GC content; and (iii) the presence of a 47.5-kbp inverted repeat in the replication termination region, an extremely rare feature in bacterial genomes, may be interpreted as a transient stage in genome evolution. The results indicate the adaptation of L. bulgaricus from a plant-associated habitat to the stable protein and lactose-rich milk environment through the loss of superfluous functions and protocooperation with Streptococcus thermophilus.
authors.affiliation: Génétique Microbienne and Mathématique, Informatique et Génome, Institut National de la Recherche Agronomique, 78352 Jouy en Josas Cedex, France. maarten.vandeguchte@jouy.inra.fr
authors.forename: M
authors.initials: M
authors.lastname: van de Guchte
authors.forename: S
authors.initials: S
authors.lastname: Penaud
authors.forename: C
authors.initials: C
authors.lastname: Grimaldi
authors.forename: V
authors.initials: V
authors.lastname: Barbe
authors.forename: K
authors.initials: K
authors.lastname: Bryson
authors.forename: P
authors.initials: P
authors.lastname: Nicolas
authors.forename: C
authors.initials: C
authors.lastname: Robert
authors.forename: S
authors.initials: S
authors.lastname: Oztas
authors.forename: S
authors.initials: S
authors.lastname: Mangenot
authors.forename: A
authors.initials: A
authors.lastname: Couloux
authors.forename: V
authors.initials: V
authors.lastname: Loux
authors.forename: R
authors.initials: R
authors.lastname: Dervyn
authors.forename: R
authors.initials: R
authors.lastname: Bossy
authors.forename: A
authors.initials: A
authors.lastname: Bolotin
authors.forename: J-M
authors.initials: JM
authors.lastname: Batto
authors.forename: T
authors.initials: T
authors.lastname: Walunas
authors.forename: J-F
authors.initials: JF
authors.lastname: Gibrat
authors.forename: P
authors.initials: P
authors.lastname: Bessières
authors.forename: J
authors.initials: J
authors.lastname: Weissenbach
authors.forename: S D
authors.initials: SD
authors.lastname: Ehrlich
authors.forename: E
authors.initials: E
authors.lastname: Maguin
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D050260:Carbohydrate Metabolism; D019143:Evolution, Molecular; D016680:Genome, Bacterial; D020071:Interspersed Repetitive Sequences; D048668:Lactobacillus delbrueckii / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D048249:Streptococcus thermophilus / Q000378:metabolism; D026801:Synteny; D015014:Yogurt / Q000382:microbiology
chemical_list: D001426:Bacterial Proteins