Development of a multilocus variable number of tandem repeat typing method for Oenococcus oeni.

Area of Science:

• Microbiology
• Food Science
• Genetics

Background:

• Oenococcus oeni drives malolactic fermentation in wine, but its genomic diversity impacts starter culture efficiency.
• Monitoring indigenous and selected O. oeni strains is crucial for understanding their survival and implantation during winemaking.

Purpose of the Study:

• To develop and validate the first typing scheme for O. oeni using multiple-locus variable number of tandem repeat (VNTR) analysis.
• To assess the discriminatory power of VNTR compared to existing methods like REA-PFGE and MLST.
• To investigate the phylogenetic relationships and geographical distribution of O. oeni strains based on VNTR profiles.

Main Methods:

• Evaluated 14 VNTR loci from the O. oeni PSU-1 strain against 18 distinct starter strains.
• Identified five highly discriminative VNTR loci for genotyping 236 O. oeni strains.
• Compared VNTR typing results with previous classifications by REA-PFGE and MLST.

Main Results:

• The developed VNTR scheme achieved a higher discriminatory power (201 VNTR types) than REA-PFGE (136 types) and MLST (110 types).
• VNTR markers demonstrated stability over time, with no changes observed in cloned strains.
• Phylogenetic groups were established, and O. oeni strains from different wine regions were statistically linked to their VNTR profiles.

Conclusions:

• Multiple-locus VNTR analysis provides a robust and highly discriminatory method for typing O. oeni.
• This new scheme facilitates effective monitoring of O. oeni populations in winemaking environments.
• VNTR loci are located in sequences homologous to membrane-anchored proteins, suggesting potential functional relevance.