RESUMO
Oenococcus oeni strains are well-known for their considerable phenotypic variations in terms of tolerance to harsh wine conditions and malolactic activity. Genomic subtractive hybridization (SH) between two isolates with differing enological potentials was used to elucidate the genetic bases of this intraspecies diversity and identify novel genes involved in adaptation to wine. SH revealed 182 tester-specific fragments corresponding to 126 open reading frames (ORFs). A large proportion of the chromosome-related ORFs resembled genes involved in carbohydrate transport and metabolism, cell wall/membrane/envelope biogenesis, and replication, recombination, and repair. Six regions of genomic plasticity were identified, and their analysis suggested that both limited recombination and insertion/deletion events contributed to the vast genomic diversity observed in O. oeni. The association of selected sequences with adaptation to wine was further assessed by screening a large collection of strains using PCR. No sequences were found to be specific to highly performing (HP) strains alone. However, there was a statistically significant positive association between HP strains and the presence of eight gene sequences located on regions 2, 4, and 5. Gene expression patterns were significantly modified in HP strains, following exposure to one or more of the common stresses in wines. Regions 2 and 5 showed no traces of mobile elements and had normal GC content. In contrast, region 4 had the typical hallmarks of horizontal transfer, suggesting that the strategy of acquiring genes from other bacteria enhances the fitness of O. oeni strains.
Assuntos
Hibridização Genômica Comparativa , Variação Genética , Genoma Bacteriano , Bactérias Gram-Positivas/genética , Vinho/microbiologia , Adaptação Biológica , DNA Bacteriano/química , DNA Bacteriano/genética , Ordem dos Genes , Bactérias Gram-Positivas/isolamento & purificação , Bactérias Gram-Positivas/fisiologia , Mutação INDEL , Dados de Sequência Molecular , Recombinação Genética , Análise de Sequência de DNA , SinteniaRESUMO
This study reports on monitoring Oenococcus oeni intraspecific diversity evolution during winemaking. Three different wines were monitored. The proportion of O. oeni species was determined by species-specific PCR and O. oeni strains were distinguished by multiplex PCR-RAPD. Each strain was tested by PCR for 16 significant markers revealed by a previous genetic comparison between a strong oenological potential strain and one with poor oenological potential. Population levels and diversity changed according to winemaking stages, oenological practices and the chemical properties of the wine. In all situations, O. oeni was the best-adapted species. Within the O. oeni group, intraspecific strain diversity decreased and the malolactic fermentation was the result of the most resistant strains with the highest number of markers.
Assuntos
Marcadores Genéticos/genética , Cocos Gram-Positivos/classificação , Cocos Gram-Positivos/crescimento & desenvolvimento , Vinho/microbiologia , Técnicas de Tipagem Bacteriana , DNA Bacteriano/genética , Fermentação , Cocos Gram-Positivos/genética , Cocos Gram-Positivos/isolamento & purificação , Microbiologia Industrial , Malatos/metabolismo , Reação em Cadeia da Polimerase , Dinâmica Populacional , Técnica de Amplificação ao Acaso de DNA Polimórfico , Especificidade da Espécie , Vitis/microbiologiaRESUMO
Using molecular techniques and sequencing, we studied the intraspecific diversity of Oenococcus oeni, a lactic acid bacterium involved in red winemaking. A relationship between the phenotypic and genotypic characterization of 16 O. oeni strains isolated from wine with different levels of enological potential was shown. The study was based on the comparative genomic analysis by subtractive hybridization between two strains of O. oeni with opposite enological potential. The genomic sequences obtained from subtractive hybridization were amplified by polymerase chain reaction and sequenced for the 16 strains. A considerable diversity among strains of O. oeni was observed.
