GSE203348
Phenotypic and integrated analysis of a comprehensive Pseudomonas aeruginosa PAO1 library of mutants lacking cyclic-di-GMP-related genes
Pseudomonas aeruginosa is a Gram-negative bacterium able to survive and adapt in a multitude of niches as well as thriving within many different hosts. This versatility lies within a large genome of ca 6Mbp and a tight control in the expression of thousands of genes. Among the regulatory mechanisms widely spread in bacteria, cyclic-di-GMP signaling is one which influences all levels of control. It is made by diguanylate cyclases and broken by phosphodiesterases while the intracellular level of this molecule drives phenotypic responses. The signaling involve modification of enzymes or proteins function upon c-di-GMP binding, including modifying the activity of regulators which in turn will impact the transcriptome. In P. aeruginosa, there are ca 40 genes encoding putative DGC or PDE. The combined activity of those enzymes should reflect the c-di-GMP concentration while specific phenotypic output could be correlated to a given set of dgc/pde. This notion of specificity has been addressed in several studies and different strains of P. aeruginosa. Here, we engineered a mutant library for the 41 individual dgc/pde genes in P. aeruginosa PAO1. In most cases, we observed a significant to slight variation in the global c-di-GMP pool, with essentially an impact on biofilm phenotypes including initial attachment and maturation, while very little is observed on motility which differs from previous studies. We observe that minor changes in c-di-GMP level have a drastic phenotypic impact thus supporting the idea of local vs global c-di-GMP pool. Our RNA-seq analysis indicates that all PAO1 dgc/pde genes are expressed in both planktonic and biofilm growth conditions and our work suggests that c-di-GMP networks owe to be reconstructed in one single strain and cannot be built by cross-comparison with studies in other strains. Overall design: We engineered a mutant library of 41 diguanylate cyclases (dgc) and phosphodiesterases (pde) genes in P. aeruginosa PAO1. We tested the impact of these mutants on biofilm formation, motility and intracellular c-di-GMP contents. We performed transcriptomic analysis on wild-type P. aeruginosa PAO1 to reveal the regulation of deg/pde genes in planktonic and biofilm growth conditions.