Abstract
Stress response plays an important role on microbial adaptation under hostile environmental conditions. It is generally unclear how the signaling transduction pathway mediates a stress response in planktonic and biofilm modes of microbial communities simultaneously. Here, we showed that metalloid tellurite (TeO32-) exposure induced the intracellular content of the secondary messenger cyclic di-GMP (c-di-GMP) of Pseudomonas aeruginosa. Two diguanylate cyclases (DGCs), SadC and SiaD, were responsible for the increased intracellular content of c-di-GMP. Enhanced c-di-GMP levels by TeO32- further increased P. aeruginosa biofilm formation and resistance to TeO32-. P. aeruginosa Delta sadC Delta siaD and PAO(1)/p(lac)-yhjH mutants with low intracellular c-di-GMP content were more sensitive to TeO32- exposure and had low relative fitness compared to the wild-type PAO(1) planktonic and biofilm cultures exposed to TeO32-. Our study provided evidence that c-di-GMP level can play an important role in mediating stress response in microbial communities during both planktonic and biofilm modes of growth.