Uncovering the regulatory network of the small RNA SuhB and its contribution to stress resistance in <i>Sphingopyxis granuli</i> TFA

Post-transcriptional regulation by small RNAs (sRNAs) enables bacteria to fine-tune gene expression and rapidly adapt to fluctuating environmental conditions. In <i>Sphingopyxis granuli</i> TFA, SuhB, the only sRNA characterized to date in this strain, was previously shown to repress <i>thnR</i> translation to control tetralin degradation under carbon catabolite repression conditions. Here, we reveal additional regulatory roles of SuhB beyond carbon metabolism. Deletion of <i>suhB</i> increases sensitivity to diverse abiotic stresses, including osmotic, oxidative, desiccation, and copper stress. Label-free quantitative proteomic analysis indicates widespread alterations in the proteome in the absence of SuhB, affecting metabolic pathways and membrane-associated processes. Moreover, a LysR-type transcription factor mutant, identified as a direct activator of <i>suhB,</i> shows similar phenotypes. Together, these findings demonstrate that SuhB functions as a global post-transcriptional regulator, coordinating metabolic balance, membrane composition, and stress resistance in <i>S. granuli</i> TFA, highlighting the critical role of sRNA-mediated regulation in environmental bacteria.