A novel sRNA srvg17985 identified in Vibrio alginolyticus involving into metabolism and stress response

Abstract

Vibrio alginolyticus is an opportunistic pathogen that is a threat to the aquaculture industry. Evidence has revealed critical roles for small RNAs (sRNAs) in bacterial physiology and pathology by modulating gene expression post transcription. However, little information about sRNA-mediated regulation in V. alginolyticus is available. We experimentally verified the existence and characterized the function of sRNA srvg17985 in V. alginolyticus ZJ-T. We identified a 179 nt and growth-phase-dependent transcript with a σ70 promoter and a ρ-independent terminator. The transcript consisted of five stem-loops and was conserved in Vibrio spp. Phenotype microarray assays showed that deletion of srvg17985 led to less use of Gly-Glu as a carbon source but a gain in ability to use l-phenylalanine as a nitrogen source. Srvg17985 regulated the osmotic stress response with stronger tolerance to NaCl but weaker tolerance to urea. In addition, srvg17985 inhibited the deamination of l-serine at pH 9.5 and promoted the hydrolysis of X-beta-d-glucuronide, thus affecting the pH stress response. Bioinformatics by IntaRNA and TargetRNA2 identified 45 common target mRNAs, some of which probably contributed to the observed phenotypes. These results indicated that srvg17985 regulated environmental adaptation. The results provide valuable information for in-depth studies of sRNA-mediated regulation mechanisms of the complex physiological processes of V alginolyticus and provide new targets for antibacterial therapeutics or attenuated vaccines for Vibrio spp.