Optogenetic Modification of <i>Pseudomonas aeruginosa</i> Enables Controllable Twitching Motility and Host Infection

Abstract

Cyclic adenosine monophosphate (cAMP) is an important secondary messenger that controls carbon metabolism, type IVa pili biogenesis, and virulence in <i>Pseudomonas aeruginosa</i>. Precise manipulation of bacterial intracellular cAMP levels may enable tunable control of twitching motility or virulence, and optogenetic tools are attractive because they afford excellent spatiotemporal resolution and are easy to operate. Here, we developed an engineered <i>P. aeruginosa</i> strain (termed <i>pactm</i>) with light-dependent intracellular cAMP levels through introducing a photoactivated adenylate cyclase gene (<i>bPAC</i>) into bacteria. On blue light illumination, <i>pactm</i> displayed a 15-fold increase in the expression of the cAMP responsive promoter and an 8-fold increase in its twitching activity. The skin lesion area of nude mouse in a subcutaneous infection model after 2-day <i>pactm</i> inoculation was increased 14-fold by blue light, making <i>pactm</i> suitable for applications in controllable bacterial host infection. In addition, we achieved directional twitching motility of <i>pactm</i> colonies through localized light illumination, which will facilitate the studies of contact-dependent interactions between microbial species.