The ComRS-SigX pathway regulates natural transformation in .

UNLABELLED

The ability to take up and incorporate foreign DNA via natural transformation is a well-known characteristic of some species of and is a mechanism that rapidly allows for the acquisition of antibacterial resistance. Here, we describe that the understudied species is also capable of natural transformation and uses a system analogous to that identified in . natural transformation is under the control of the alternative sigma factor (also known as ), whose expression is induced by two types of peptide signals: CSP ( c ompetence s timulating p eptide, encoded by ) and XIP ( -inducing p eptide, encoded by ). These systems induce competence via either the two-component signal-transduction system ComDE or the RRNPP transcriptional regulator ComR, respectively. Protein and nucleotide homology searches identified putative orthologs of and in , but not homologs of (also known as ). We demonstrate that natural transformation in is induced by a small, double-tryptophan containing competence-inducing peptide (XIP), akin to that of , and requires the presence of the and orthologs for efficient transformation. Additionally, we find that natural transformation is induced in by both the native XIP and the XIP variant of , implying that crosstalk between the two species is possible. This process has been harnessed to construct gene deletions in and provides a method to genetically manipulate this understudied species.

IMPORTANCE

Natural transformation is the process by which bacteria take up DNA and allows for acquisition of new genetic traits, including those involved in antibiotic resistance. This study demonstrates that the understudied species is capable of natural transformation using a peptide-pheromone system like that previously identified in and provides a framework for future studies concerning this organism.