Natural Transformation of Oral Streptococci

Natural transformation is found in most groups of oral streptococci, including the mitis, the anginosus, and the mutans groups. This ability has been applied as a powerful tool to explore streptococcal gene functions and regulatory pathways, particularly in Streptococcus mutans and Streptococcus gordonii . The range of strains and species amenable to transformation has expanded in recent years with the identification of several competence-stimulating peptide signals (CSPs). In this chapter we present protocols for natural transformation in strains found in the three groups of transformable oral streptococci, with focus on methods using synthetic CSPs. We also include suggestions on how to optimize competence conditions for individual species or strains.