Roles of Alp and Prt Regulons in the Response of Pseudomonas aeruginosa to UV ‐C Light

UV light is a well-studied environmental DNA damaging agent. Bacterial cells respond to UV exposure by upregulating several pathways to repair and tolerate the lesions induced by this agent. The SOS response is the primary pathway activated during genotoxic stress that can shift the balance between mutagenesis and genome integrity. However, in Pseudomonas aeruginosa, the canonical SOS response is not the only pathway activated after DNA damage. This opportunistic pathogen also activates the production of pyocins (Prt regulon) and an autolysis pathway controlling the alp genes (Alp regulon) in response to DNA damage. This study aims to characterise gene expression changes in response to UV-C damage. We performed RNA sequencing analysis to determine the set of differentially expressed genes, and qRT-PCR to track the course of expression of representative genes from each regulon. Our results show that the canonical LexA-regulated SOS response is the earliest activated one, while the Alp regulon displays a delayed induction. We also investigated the contribution of the Alp and Prt regulons to UV-induced cell death and found that the predominant mechanism varies between PAO1 sublines.