Professor Jeonbuk National University Iksan-si, Cholla-bukto, Republic of Korea
The cryptochrome/photolyase family (CPF) consists of structurally conserved flavoproteins with diverse functions. Here, we identified and characterized a putative CPF protein (Pc-Phr) in Pseudomonas cichorii JBC1 (PcJBC1). The absorption spectrum of recombinant Pc-Phr revealed an oxidized FAD form (peak at 445 nm) in the dark, which shifted under blue light (BL) to the semiquinone radical (587, 632 nm) and fully reduced states (360 nm). Pc-Phr exhibited BL-dependent photoreactivation, repairing UV-induced CPD dimers in vitro and restoring UVC-irradiated PcJBC1 viability in vivo—effects absent in a phr-deficient mutant. Additionally, BL exposure upregulated phr expression in UVC-irradiated PcJBC1 cells, underscoring its role in UV damage repair. Pc-Phr also enhanced PcJBC1 virulence by promoting bacterial survival, growth, and adhesion as well as resistance to oxidative stress, UVC, and high-intensity BL exposure. Since plant disease development depends on both virulence and stress tolerance of pathogen, our findings highlight photolyase as a key factor in PcJBC1's ecological fitness and virulence. Future studies should explore the regulatory mechanisms linking photolyase activity to bacterial growth and host interactions
