Systematic Functional Genomics Analysis of the Oral Pathogen Streptococcus Mutans

Project Summary In this project we will construct a powerful new tool to systematically identify infection-relevant genes in the dental caries pathogen Streptococcus mutans. Sequence-defined arrayed mutant libraries are available for several medical and model bacterial species. These tools have greatly accelerated the pace of genetic screens

and the identification of important pathogenic genetic determinants. We will construct an arrayed transposon mutant library in the model laboratory strain UA159 and use a sequencing approach to determine the identity of each mutant. After constructing the library, we will use it to study genetic determinants of sucrose-mediated

biofilm formation, which is a critical virulence trait of S. mutans. We will also use a comparative transposon sequencing (Tn-seq) approach to identify genes that provide a selective advantage in biofilms. The results of this research will include the following: 1) construction of an arrayed and sequence defined transposon mutant

resource for the S. mutans research community, 2) an improved understanding of the genetic determinants of sucrose-mediated biofilm formation both in monoculture and in complex communities, and 3) we expect this knowledge to contribute to the development of new approaches to target and reduce S. mutans colonization of

the oral cavity. This project will also provide training opportunities for undergraduate and graduate students from Arkansas, an area that is underrepresented in biomedical research.