Modulation of physiological functions and metabolome of <i>Vibrio alginolyticus</i> by quorum-regulatory sRNA, Qrr1

Vibrio alginolyticus, the causative agent of aquatic vertebrates and invertebrates, can cause severe infections (e.g. septicemia, gill necrosis, and surface ulcers) and high mortality in aquatic organisms, leading to serious economic losses in global aquaculture. Small non-coding RNAs (sRNAs), emerging modulators of gene expression, played vital regulatory roles in virulence, pathogenicity, and physiological metabolism of bacteria. In this work, the modulation of physiological functions and metabolome of V. alginolyticus by the quorum-regulatory sRNA, Qrr1, was figured out. We found that the deletion of qrr1 induced significant cell shape elongation. Meanwhile, Qrr1 could inhibit the production of alkaline serine protease by weakening the expression of main regulator LuxR in the quorum sensing (QS) system. Moreover, the untargeted metabolomics and lipidomics approaches showed that most of nucleotides, organic acids, carbohydrates, and lipidome (both lipid content and category) were significantly altered in response to the qrr1 deletion. Spearman correlation analysis demonstrated that most of the intermediates involved in glutamate metabolism, sphingolipid metabolism, and glycerolipid metabolism displayed high correlations with cell virulence factors. These findings illuminate the mechanism of bacterial virulence regulation and further exploit potential therapeutic targets for virulence prevention in V. alginolyticus.