High c-di-GMP promotes expression of fpr-1 and katE involved in oxidative stress resistance in Pseudomonas putida KT2440
Oxidative stress is an unavoidable consequence of interactions with various reactive oxygen species (ROS)-inducing agents that would damage cells or even cause cell death. Bacteria have developed defensive systems, including induction of stress-sensing proteins and detoxification enzymes, to handle oxidative stress. Cyclic diguanylate (c-di-GMP) is a ubiquitous intracellular bacterial second messenger that coordinates diverse aspects of bacterial growth and behavior. In this study, we revealed a mechanism by which c-di-GMP regulated bacterial oxidative stress resistance in Pseudomonas putida KT2440. High c-di-GMP level was found to enhance bacterial resistance towards hydrogen peroxide. Transcription assay showed that expression of two oxidative stress resistance genes, fpr-1 and katE, was promoted under high c-di-GMP level. Deletion of fpr-1 and katE both decreased bacterial tolerance to hydrogen peroxide and weakened the effect of c-di-GMP on oxidative stress resistance. The promoted expression of fpr-1 under high c-di-GMP level was caused by increased cellular ROS via a transcriptional regulator FinR. We further demonstrated that the influence of high c-di-GMP on cellular ROS depend on the existence of FleQ, a transcriptional regulatory c-di-GMP effector. Besides, the regulation of katE by c-di-GMP was also FleQ dependent in an indirect way. Our results proved a connection between c-di-GMP and oxidative stress resistance and revealed a mechanism by which c-di-GMP regulated expression of fpr-1 and katE in P. putida KT2440.
KeywordsOxidative stress resistance c-di-GMP fpr-1 katE FleQ Pseudomonas putida KT2440
The research was financially supported by The National Key Research and Development Program of China (2016YFD0800206), the National Natural Science Foundation of China (41571230), and The China Postdoctoral Science Foundation (2018M642861).
Compliance with ethical standards
This article does not contain any studies with human participants or animals performed by any of the authors.
Conflict of interest
The authors declare that they have no conflict of interest.
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