Project description:Drought and salinity are most ubiquitous environmental factors that causing hyperosmotic threats to Sphingomonas and impairs their efficiency of performing environmental functions. However, bacteria have developed various responses and regulation systems to coping with these abiotic challenges. Among which post-transcriptional regulation plays vital roles in regulating gene expression and cellular homeostasis, as hyperosmotic stress conditions could lead to induction of specific small RNA (sRNA) that participates in stress response regulation. Here, we report a candidate functional sRNAs landscape of S. melonis which could help for comprehensive analyses of sRNA regulation in Sphingomonas species. WGCNA analysis revealed a 263 nt sRNA SNC251 which transcribed from its own promoter and shew the most dramatic correlation coefficient with hyperosmotic factors was characterized. An in vivo translation-reporter system constructed in this study revealed positive regulation and feedback mechanisms between the SNC251 and nicotine degradation genes. Deletion of snc251 affected multiple cellular processes and nicotine degradation capacity of S. melonis TY, while overexpression of SNC251 facilitated the biofilm formation capability of TY under hyperosmotic stress. Two genes of TonB system were further verified could be activated by SNC251, which also means SNC251 is a trans-acting small RNA. Briefly, this research reported a summary of sRNAs which participate in hyperosmotic stress response in S. melonis TY and revealed a novel sRNA SNC251 which is necessary for hyperosmotic stress response.