En-Gen: Bacterial Communication in Microbial Mats: A Metagenomic Approach to Understanding Quorum Sensing Gene Diversity and Expression

University South Carolina Research Foundation, Columbia SC

Investigators

Abstract

The bacterial world is the largest unexplored biological reservoir on Earth, yet little is known about how its members function. Bacteria appear to exist in complex social networks which depend on cooperation and communication that ultimately affect community function. Communication often involves a bacterial cell-to-cell process called quorum sensing (QS), and is used by bacteria to detect and control their responses to other bacteria. While QS was discovered over three decades ago, understanding has been limited to the less than 1% of all bacteria that can be grown in the laboratory so its ecological relevance is not yet clear. This project addresses this knowledge gap through a study of the diversity and expression of QS genes in natural habitats, using microbial mats as the model natural habitat. Microbial mats are one of the oldest and most diverse biological systems on Earth, and have been key to Earth's geochemical evolution. These microbially-dominated habitats are ideal for understanding environment-cell interactions as well as cell-cell interactions. This project will sequence all of the bacteria in the microbial mat (the so-called ' microbial metagenome') and look for possible QS genes. Then QS gene expression will be followed over time and space to determine what factors control their activities. Finally, QS gene expression will be correlated with major groups of bacteria in the mat in order to determine which groups are the key regulators in the mat. The outreach program includes: (1) a public exhibit on the 'Unseen World of Bacteria' at a nationally-renowned Zoo; (2) development of a 'Young Genomic Scientist' program in primary/secondary schools; (3) involvement of minority graduate and undergraduate students in research. A QS expression array with the newly-discovered QS genes from this study and those from other databases will be developed as a community resource. This expression array chip can be used by scientists interested in bacterial cell-cell communication in natural and in human (pathogen) systems.