Genome editing by natural genetic transformation in Streptococcus mutans

Area of Science:

• Microbiology
• Molecular Biology
• Bacterial Genetics

Background:

• Classical mutagenesis relies on selective markers, which can be cumbersome and lead to unwanted gene accumulation.
• Alternative strategies using temporary insertions face challenges in designing counter-selected markers.
• Direct genome editing offers a solution to overcome the drawbacks of existing mutagenesis techniques.

Purpose of the Study:

• To develop and describe a simplified direct genome editing strategy for Streptococcus mutans (S. mutans).
• To demonstrate the application of this method in the S. mutans UA159 reference strain.
• To provide a more efficient and less problematic approach for targeted mutagenesis in bacteria.

Main Methods:

• Construction of a single synthetic donor amplicon containing the desired mutation and extensive homology arms.
• Transformation of highly competent S. mutans cells, induced by a synthetic competence pheromone.
• Identification of desired mutants through a simple Polymerase Chain Reaction (PCR) screening of a small number of clones.

Main Results:

• The developed strategy enables direct genome editing in S. mutans UA159 with high efficiency.
• The method requires only one transformation step and a simple PCR screen, significantly reducing complexity.
• This approach avoids the accumulation of unwanted genes associated with traditional marker-based mutagenesis.

Conclusions:

• Direct genome editing provides an advantageous alternative to classical and temporary insertion-based mutagenesis strategies.
• The described method offers extreme simplicity and efficiency for targeted mutagenesis in S. mutans.
• This technique facilitates precise genetic modifications in bacteria, paving the way for advanced genetic studies.