Identification of Putative Phr Signaling Peptide Encoding Genes in Non-Bacillus Species Using a Bioinformatic Approach

Quorum sensing occurs when bacterial cells secrete a specific signaling molecule that is then sensed by proximal bacterial cells, and it mediates regulation of important cell processes such as pathogenesis, antibiotic production, and biofilm formation. Quorum sensing is a common technique utilized by bacterial cells to communicate and monitor neighboring cell density; however this type of signaling has been closely studied in only a handful of microbes. Bacillus subtilis, a Gram-positive bacterium, has been shown to produce a group of quorum sensing molecules known as Phr peptides. Using bioinformatics, this study aims to identify genes in a variety of bacterial genomes (non-Bacillus species) that appear to encode Phr peptides involved in quorum sensing. Putative Phr genes were derived and sorted from all sequenced bacterial genomes. They were then scored based on the similarity of their genetic features to known Phr peptides found in Bacilli. A score of “3” would imply a high probability of being a Phr encoding gene whereas a score of “0” indicated a low probability. Thus far we have identified 146 genomes of varying bacterial species that have a high likelihood of utilizing Phr mediated signaling. The last portion of this project aims to identify common features that define subclasses of putative Phr genes. The overall objective is to be able to determine the array of bacteria that likely utilize Phr mediated quorum sensing.