Small RNA-mediated regulation of stress tolerance in Deinococcus radiodurans

Deinococcus radiodurans exhibits exceptional resilience to extreme stressors like ionizing radiation, oxidative damage, and desiccation. This extraordinary resistance stems from a sophisticated regulatory network that enables survival in environments lethal to most organisms. Within this regulatory framework, small RNAs (sRNA) have emerged as key regulators of the stress response. Acting primarily through post-transcriptional regulation, sRNA modulates gene expression by binding target mRNAs to influence their stability or translation, enabling rapid cellular adaptation. Despite significant advances in understanding D. radiodurans' DNA repair capabilities, studies of its RNA-based regulatory pathways are relatively limited. Recent studies have revealed the critical role of sRNAs in D. radiodurans, particularly through advanced RNA sequencing techniques that identified numerous previously unknown sRNAs. These sRNAs act as global regulators, altering the expression of genes involved in the stress response, DNA repair, and metal homeostasis. Mn²⁺ homeostasis is an important adaptation that enables D. radiodurans to alleviate oxidative stress, a major risk in radiation-rich environments. The role of sRNA in regulating D. radiodurans is more complex than simply responding to the stress. In addition, sRNA controls other bacterial systems, such as quorum sensing and biofilm formation, though these systems are still poorly understood in D. radiodurans. This review focuses on the sRNAs of D. radiodurans and their responses to various stresses. We highlight these riboregulators for their role in one of the most remarkable bacterial survival mechanisms.