Vvrr2: A new Vibrio ncRNA involved in dynamic synthesis of multiple biofilm matrix exopolusaccharides, biofilm structuring and virulence

Abstract

Vibrio alginolyticus is a widely distributed aquatic pathogen. Therefore, it is urgent to better understand the pathogenic mechanism of V. alginolyticus infection. With RNA-seq, we previously found a novel ncRNA closely related to V. alginolyticus adhesion regulation and named it as Vvrr2. In the present study, we found that Vvrr2 was involved in environmental adaptation through a negative regulatory mode. Meanwhile, the Vvrr2-overexpression strain was impaired in adhesion, growth, biofilm formation, motility, drug resistance, and virulence. Furthermore, confocal laser microscopy and scanning electron microscopy showed that overexpression of Vvrr2 resulted in failing of biofilm structuring. The effect of Vvrr2-overexpression on the type and content of polysaccharide, protein and nucleic acid in the biofilm was also confirmed by Raman spectroscopy. fliG, lps, and cheV, which are closely related to the adhesion, motility and thus biofilm formation were proved to be the target genes of Vvrr2 by GFP reporter gene analysis. These indicated that Vvrr2 participated in the formation of biofilm in terms of chemical composition and structural completion, through regulations of fliG, lps, and cheV.