CRISPR/Cas12a-mediated genome engineering in the photosynthetic bacterium Rhodobacter capsulatus.

Purple non-sulfur photosynthetic bacteria (PNSB) such as Rhodobacter capsulatus serve as a versatile platform for fundamental studies and various biotechnological applications. In this study, we sought to develop the class II RNA-guided CRISPR/Cas12a system from Francisella novicida for genome editing and transcriptional regulation in R. capsulatus. Template-free disruption method mediated by CRISPR/Cas12a reached ~ 90% editing efficiency when targeting ccoO or nifH gene. When both genes were simultaneously edited, the multiplex editing efficiency reached > 63%. In addition, CRISPR interference (CRISPRi) using deactivated Cas12a was also evaluated using reporter genes egfp and lacZ, and the transcriptional repression efficiency reached ~ 80%. In summary, our work represents the first report to develop CRISPR/Cas12a-mediated genome editing and transcriptional regulation in R. capsulatus, which would greatly accelerate PNSB-related researches.