title: Role of hypermutability in the evolution of the genus Oenococcus.
abstract: Oenococcus oeni is an alcohol-tolerant, acidophilic lactic acid bacterium primarily responsible for malolactic fermentation in wine. A recent comparative genomic analysis of O. oeni PSU-1 with other sequenced lactic acid bacteria indicates that PSU-1 lacks the mismatch repair (MMR) genes mutS and mutL. Consistent with the lack of MMR, mutation rates for O. oeni PSU-1 and a second oenococcal species, O. kitaharae, were higher than those observed for neighboring taxa, Pediococcus pentosaceus and Leuconostoc mesenteroides. Sequence analysis of the rpoB mutations in rifampin-resistant strains from both oenococcal species revealed a high percentage of transition mutations, a result indicative of the lack of MMR. An analysis of common alleles in the two sequenced O. oeni strains, PSU-1 and BAA-1163, also revealed a significantly higher level of transition substitutions than were observed in other Lactobacillales species. These results suggest that the genus Oenococcus is hypermutable due to the loss of mutS and mutL, which occurred with the divergence away from the neighboring Leuconostoc branch. The hypermutable status of the genus Oenococcus explains the observed high level of allelic polymorphism among known O. oeni isolates and likely contributed to the unique adaptation of this genus to acidic and alcoholic environments.
authors.affiliation: Department of Viticulture and Enology, University of California, One Shields Ave., Davis, CA 95616, USA.
authors.forename: Angela M
authors.initials: AM
authors.lastname: Marcobal
authors.forename: David A
authors.initials: DA
authors.lastname: Sela
authors.forename: Yuri I
authors.initials: YI
authors.lastname: Wolf
authors.forename: Kira S
authors.initials: KS
authors.lastname: Makarova
authors.forename: David A
authors.initials: DA
authors.lastname: Mills
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D002352:Carrier Proteins / Q000235:genetics* / Q000502:physiology; D053843:DNA Mismatch Repair; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D012321:DNA-Directed RNA Polymerases / Q000235:genetics; D019143:Evolution, Molecular; D006095:Gram-Positive Cocci / Q000235:genetics*; D008969:Molecular Sequence Data; D051719:MutS DNA Mismatch-Binding Protein / Q000235:genetics* / Q000502:physiology; D017354:Point Mutation; D011110:Polymorphism, Genetic; D017422:Sequence Analysis, DNA
chemical_list: D001426:Bacterial Proteins; D002352:Carrier Proteins; D004269:DNA, Bacterial; D012321:DNA-Directed RNA Polymerases; C105078:RNA polymerase beta subunit; D051719:MutS DNA Mismatch-Binding Protein