title: Succinate dehydrogenase mutant of Listonella anguillarum protects rainbow trout against vibriosis.
abstract: Listonella anguillarum is a Gram-negative facultative anaerobic rod causing hemorrhagic septicemia in marine and rarely in freshwater fish. Succinate dehydrogenase (SDH) plays an important role in the tricarboxylic acid (TCA) cycle by oxidizing succinate to fumarate while reducing ubiquinone to ubiquinol. Recent studies indicate that central metabolic pathways, including the TCA cycle, contribute to bacterial virulence. However, the role of SDH in L. anguillarum virulence has not been studied. Here, we report in-frame deletion of the succinate dehydrogenase iron-sulfur protein (SDHB) and its role in L. anguillarum virulence in rainbow trout. To accomplish this goal, upstream and downstream regions of the L. anguillarum sdhB gene were amplified in-frame and cloned into a suicide plasmid. The chromosomal sdhB gene of L. anguillarum was deleted by homologous recombination. Virulence and immunogenicity of the L. anguillarum ΔsdhB mutant (LaΔsdhB) were determined in rainbow trout. Results show that LaΔsdhB was highly attenuated in rainbow trout, and fish immunized with LaΔsdhB displayed high relative survival rate after exposure to wild type L. anguillarum. These findings indicate SDH is important in L. anguillarum virulence in rainbow trout, and LaΔsdhB could be used as an immersion, oral, or injection vaccine to protect rainbow trout against vibriosis.
authors.affiliation: Department of Fisheries Technology Engineering, Faculty of Marine Science, Karadeniz Technical University, Trabzon 61530, Turkey. Electronic address: ialtinok@ktu.edu.tr.
authors.forename: Ilhan
authors.initials: I
authors.lastname: Altinok
authors.affiliation: Department of Fisheries Technology Engineering, Faculty of Marine Science, Karadeniz Technical University, Trabzon 61530, Turkey.
authors.forename: Erol
authors.initials: E
authors.lastname: Capkin
authors.affiliation: Department of Basic Sciences, College of Veterinary Medicine, Mississippi State University, Mississippi State, MS 39762, USA. Electronic address: a.karsi@msstate.edu.
authors.forename: Attila
authors.initials: A
authors.lastname: Karsi
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics; D001428:Bacterial Vaccines / Q000276:immunology*; D005393:Fish Diseases / Q000517:prevention & control*; D007506:Iron-Sulfur Proteins / Q000235:genetics; D053526:Listonella / Q000201:enzymology* / Q000235:genetics / Q000472:pathogenicity; D017686:Oncorhynchus mykiss / Q000276:immunology* / Q000382:microbiology; D017384:Sequence Deletion; D013385:Succinate Dehydrogenase / Q000235:genetics*; D014613:Vaccines, Attenuated / Q000276:immunology; D014735:Vibrio Infections / Q000517:prevention & control / Q000662:veterinary*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D007506:Iron-Sulfur Proteins; D014613:Vaccines, Attenuated; D013385:Succinate Dehydrogenase
keywords: Listonella anguillarum; Rainbow trout; SDH; Vaccine; sdhB