title: Role of alternative sigma factor 54 (RpoN) from Vibrio anguillarum M3 in protease secretion, exopolysaccharide production, biofilm formation, and virulence.
abstract: The sigma factor σ(54) (RpoN) is an important regulator of bacterial response to environmental stresses. Here, we demonstrate the roles of RpoN in Vibrio anguillarum M3 by comparative investigation of physiological phenotypes and virulence of the wild-type, an rpoN mutant, and an rpoN complemented strain. Disruption of rpoN was found to decrease biofilm formation, production of exopolysaccharides, and production of the metalloproteases EmpA and PrtV. Injection experiments in fish showed that the M3 ΔrpoN mutant was attenuated in virulence when administrated either by intramuscular injection or by immersion challenge. Slower proliferation of the mutant in fish was also observed. Complementation of the mutant strain with rpoN restored some of the phenotypes to wild-type levels. RpoN was involved in regulation of some virulence-associated genes, as shown by real-time quantitative reverse PCR analysis. These results revealed a pleiotropic regulatory role of RpoN in biofilm formation, production of proteases and exopolysaccharides, and virulence in V. anguillarum M3.
authors.affiliation: Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, 7 Nanhai Road, Qingdao 266071, People's Republic of China.
authors.forename: Bin
authors.initials: B
authors.lastname: Hao
authors.forename: Zhao-Lan
authors.initials: ZL
authors.lastname: Mo
authors.forename: Peng
authors.initials: P
authors.lastname: Xiao
authors.forename: Hai-Jian
authors.initials: HJ
authors.lastname: Pan
authors.forename: Xin
authors.initials: X
authors.lastname: Lan
authors.forename: Gui-Yang
authors.initials: GY
authors.lastname: Li
mesh_terms: D000818:Animals; D018441:Biofilms / Q000254:growth & development*; D004195:Disease Models, Animal; D005393:Fish Diseases / Q000382:microbiology / Q000473:pathology; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D055786:Gene Knockout Techniques; D005816:Genetic Complementation Test; D010447:Peptide Hydrolases / Q000378:metabolism*; D010473:Perciformes; D011135:Polysaccharides, Bacterial / Q000378:metabolism*; D051877:RNA Polymerase Sigma 54 / Q000235:genetics / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D014733:Vibrio / Q000378:metabolism / Q000472:pathogenicity* / Q000502:physiology*; D014735:Vibrio Infections / Q000382:microbiology / Q000473:pathology; D014774:Virulence
chemical_list: D011135:Polysaccharides, Bacterial; D051877:RNA Polymerase Sigma 54; D010447:Peptide Hydrolases