PA5402-5407 of Pseudomonas aeruginosa Regulate the Expression of the Aa3-Type Oxidases and Their Growth Under Carbon Starvation and High-Density Conditions.

Our previous studies identified PA5407 in Pseudomonas aeruginosa as a new regulatory protein for bacterial division and named it ZapAL. This protein enhances the assembly of the key bacterial division protein FtsZ and participates in the assembly of the bacterial Z-ring, but its physiological function is not clear. ZapAL is in the same gene cluster as PA5402-5406, and in this study, we found that these genes are involved in the regulation of bacterial growth under nutrient deficiency and high-density conditions. The expression of Aa3 oxidase increases significantly at the end of the stationary phase of bacterial growth under aerobic conditions, and appropriately accelerate energy intake to adapt to the adversity. In our study, we found that the knockout of PA5402-5407 in P. aeruginosa promotes the further expression of Aa3 oxidase and its expression increased more and faster than the wild type, especially under carbon starvation and high-density conditions. This results in a larger bacteria population, but the average length of the bacteria is abnormally reduced. In summary, our study found that the P. aeruginosa gene cluster PA5402-5407 regulated the expression of Aa3 oxidase in the late stationary phase, and these genes balance energy intake, growth and division of bacteria under adverse conditions.