Evaluation of the genetic polymorphism among Lactococcus lactis subsp. cremoris strains using comparative genomic...

Area of Science:

• Microbiology
• Genomics
• Food Science

Background:

• Lactococcus lactis subsp. cremoris is crucial for dairy fermentation.
• Understanding strain genetic diversity is key for selecting effective starter cultures with specific technological and sensory properties.

Purpose of the Study:

• To investigate the genetic variation among eight Lactococcus lactis subsp. cremoris strains.
• To identify genetic markers for differentiating strains and their variants.
• To facilitate the formulation of compatible and complementary mixed starters for industrial use.

Main Methods:

• Microarray-based comparative genomic hybridization (CGH) was employed to analyze genome-wide differences.
• Multilocus sequence analysis (MLSA) using eight genes was performed to assess genetic relatedness.
• Strain grouping and identification of divergent genes related to metabolism, biosynthesis, osmoregulation, and proteolysis were conducted.

Main Results:

• CGH analysis enabled strain grouping and pinpointed genes involved in key metabolic pathways.
• MLSA clustering demonstrated a strong correlation with CGH groupings.
• Specific strain clusters were identified (e.g., HP, ATCC 19257, Wg2 together; E8 separate; SK11 separate).

Conclusions:

• Genetic profiles serve as valuable markers for distinguishing Lactococcus lactis subsp. cremoris strains.
• This knowledge supports the rational selection of strains for developing improved starter cultures.
• Optimized strain selection opens new possibilities for industrial dairy applications.