Glutathione impacts Hfq condensation in nitrogen-starved Escherichia coli

Nitrogen (N) is essential for bacterial growth, and adaptation to N starvation involves extensive reprogramming of metabolism and gene expression. A hallmark subcellular feature in long-term N-starved Escherichia coli cells is the presence of biomolecular condensates of the major bacterial RNA regulator Hfq. The Hfq condensates, which accumulate gradually during N starvation, contribute to adaptation by modulating RNA metabolism and central metabolic pathways. Metabolites play central roles in stress responses, often acting as modulators of protein function to support survival and recovery. Glutathione (GSH), a universal stress protectant, has broad roles in bacterial stress adaptation, yet its function during N starvation remains unexplored. Using a GSH-deficient mutant (ΔgshAB), we show that GSH is required for optimal survival and recovery from prolonged N starvation. We reveal that GSH regulates the temporal dynamics of Hfq condensation and dissipation during N starvation and recovery from N starvation, respectively, via an as-yet unknown mechanism. However, the contribution of GSH to survival during and recovery from N starvation and Hfq condensation dynamics seems to be unlinked. Overall, the results point to a role for GSH in the adaptive response to N starvation, potentially extending its canonical function as a stress protectant.IMPORTANCENitrogen is a vital nutrient for bacterial growth. When nitrogen becomes scarce, bacteria must quickly adapt to survive. Escherichia coli forms tiny structures called Hfq condensates, which help manage genetic information flow and metabolism. Small molecules called metabolites aid bacteria in coping with stress, and one such molecule, glutathione (GSH), protects cells under various stress conditions. GSH's role during nitrogen starvation is unknown. We used an E. coli mutant unable to produce GSH and found that these bacteria struggle to survive and recover from nitrogen starvation. We also discovered that GSH helps control when and how Hfq condensates form and disappear. Although these two functions seem unrelated, our study highlights GSH's versatile role in helping bacteria adapt to nitrogen stress.