GSE120889
The Pleiotropic Effects of c-di-GMP content in Pseudomonas syringae
Although the ubiquitous bacterial secondary messenger cyclic diguanylate (c-di-GMP) plays important roles in various cellular functions including the formation of biofilm in a wide range of bacteria, its function in model plant pathogen Pseudomonas syringae is largely elusive. In order to test this in P. syringae, we overexpressed a diguanylate cyclase (YedQ) and a phosphodiesterase (YhjH) that are originally from Escherichia coli, resulting in high and low c-di-GMP levels in P. syringae, respectively. Through performing genome-wide RNA sequencing of these two strains, we found that c-di-GMP regulates (i) fliN, fliE and flhA genes, which are associated with flagellar assembly, (ii) alg8 and alg44, which are related to exopolysaccaride biosynthesis pathway, (iii) pvdE, pvdP and pvsA genes, related to siderophore biosynthesis pathway, and (iv) sodA, which is a superoxide dismutase. In particular, we identified five genes sensitive to elevated c-di-GMP level and constructed five luciferase-based reporters that effectively respond to intracellular level of c-di-GMP in P. syringae, which can be used to measure c-di-GMP levels in vivo in the future. Based on the RNA-seq results, phenotypic assays confirmed that c-di-GMP regulated many important biological pathways in P. syringae, such as negative regulation of type III secretion system (T3SS) and motility as well as positive regulation of EPS production, siderophore production and oxidative stress resistance. Taken together, the present study demonstrated that c-di-GMP is closely related to virulence and stress response in P. syringae, suggesting that tuning its level can be a new strategy to protect plants from the attack of this pathogen in the future. Overall design: Detecting the effects of c-di-GMP by changing c-di-GMP content in Pseudomonas syringae