On the role of choline in natural DNA transformation in Streptococcus pneumoniae

This is the authors' abstract. We don't add key points for this paper.

Background Under laboratory conditions, DNA transformation of Streptococcus pneumoniae is facilitated by the addition of the Competence Stimulating Peptide (CSP). We recently showed that CSP can be dispensable for natural transformation but this depends on both the strains and the growth medium. Indeed, S. pneumoniae D39 biofilms or planktonic cells can naturally transform when grown in CDM medium but not in C+Y medium. Methods and results By comparing the recipes of the two media, we supplemented C+Y with a number of metabolites found in CDM and observed that increasing choline concentration in C+Y was sufficient to support natural transformation in D39 but also in S. pneumoniae ATCC49619. The addition of choline had a major impact in modulating the D39 transcriptome including in pathways related to competence induction and in the decrease expression of the capsule operon. Conclusion A change in the concentration of choline can impact natural transformation and thus contribute to the evolution of S. pneumoniae .