Legionella pneumophila belongs to the growing list of pathogens capable of undergoing natural genetic transformation. Natural transformation results from the capture, import and integration of exogenous DNA and is a common mode of horizontal gene transfer (HGT). Natural transformation is considered the sole mechanism of HGT inherent to the species. It is under control of the recipient cell that actively acquires genetic material from its direct environment using a dedicated DNA uptake system. We found that the pLPL plasmid, found in ~5% of clinical isolates, associates with low transformability levels. The pLPL plasmid carries a homolog of RocR, termed RocRp. RocR is a chromosome-encoded small RNA known to repress expression of the DNA uptake system. The purpose of this study was to determine the effect of the absence of pLPL or the deletion of the RocR homolog (RocRp) on the transcriptional profile of the Legionella pneumophila clinical isolate HL-0640-3009.