RESEARCH ARTICLE Streptococcus thermophilus Biofilm Formation: A Remnant Trait of Ancestral Commensal Life? Benoit Couvigny1,2☯, Claire Thérial1,2☯¤, Céline Gautier1,2, Pierre Renault1,2, Romain Briandet1,2, Eric Guédon1,2* 1 INRA, UMR 1319 Micalis, Domaine de Vilvert, F-78352 Jouy-en-Josas, France, 2 AgroParisTech, UMR MICALIS, Jouy-en-Josas, France ☯ These authors contributed equally to this work. ¤ Current address: Laboratoire Eau Environnement et Systèmes Urbains, Faculté des sciences et technologie, Créteil, France *
[email protected] a11111 Abstract Microorganisms have a long history of use in food production and preservation. Their adap- tation to food environments has profoundly modified their features, mainly through genomic flux. Streptococcus thermophilus, one of the most frequent starter culture organisms con- sumed daily by humans emerged recently from a commensal ancestor. As such, it is a use- OPEN ACCESS ful model for genomic studies of bacterial domestication processes. Many streptococcal species form biofilms, a key feature of the major lifestyle of these bacteria in nature. Howev- Citation: Couvigny B, Thérial C, Gautier C, Renault S thermophilus P, Briandet R, Guédon E (2015) Streptococcus er, few descriptions of . biofilms have been reported. An analysis of the thermophilus Biofilm Formation: A Remnant Trait of ability of a representative collection of natural isolates to form biofilms revealed that S. ther- Ancestral Commensal Life? PLoS ONE 10(6): mophilus was a poor biofilm producer and that this characteristic was associated with an in- e0128099. doi:10.1371/journal.pone.0128099 ability to attach firmly to surfaces. The identification of three biofilm-associated genes in the Academic Editor: Ali Al-Ahmad, University Hospital strain producing the most biofilms shed light on the reasons for the rarity of this trait in this of the Albert-Ludwigs-University Freiburg, GERMANY species.