title: Impact of co-deficiency of RpoN and RpoS on stress tolerance, virulence and gene regulation in Edwardsiella tarda.
abstract: Edwardsiella tarda the etiological agent for edwardsiellosis, a devastating fish disease prevailing in worldwide aquaculture industries was subjected to a molecular genetic study. To research into the influence when RpoN (σ(54) ) and RpoS (σ(38) ) were deleted simultaneously, the double deletion mutant of RpoN (σ(54) ) and RpoS (σ(38) ), namely rnrs, was constructed. Firstly, RpoN and RpoS are both essential for H2 O2 , starvation, high osmotic pressure and acid resistance, which have synergistic effect. Secondly, virulence of rnrs reduces significantly compared to E. tarda EIB 202 WT, ΔrpoN mutant and ΔrpoS mutant. Furthermore, transcriptional control of rpoS by rpoN in stationary phase was observed through qRT-PCR, while rpoS had no influence on rpoN in the level of transcription. Meanwhile, regulation of flagellar sigma factor σ(F) (FliA) and other flagella-related genes including flgA, flgK, flgL, motA, and motB by rpoS, and rpoN was found. fliA and other flagella-related genes were controlled positively by rpoN, while negatively by rpoS. At last, two differential expression genes in transcriptional level of rnrs strain were detected by DD-RT-PCR, namely cheY and narK. This study therefore indicated interaction between sigma factors RpoN and RpoS, which modulates stress response, virulence, motility, and provides new insights into the regulatory networks of E. tarda.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, P. R., China.
authors.forename: Enfu
authors.initials: E
authors.lastname: Liu
authors.forename: Jiang
authors.initials: J
authors.lastname: Ye
authors.forename: ShanShan
authors.initials: S
authors.lastname: Song
authors.forename: Keping
authors.initials: K
authors.lastname: Wang
authors.forename: Yuanxing
authors.initials: Y
authors.lastname: Zhang
authors.forename: Huizhan
authors.initials: H
authors.lastname: Zhang
mesh_terms: D000143:Acids / Q000494:pharmacology; D000818:Animals; D020609:Edwardsiella tarda / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D005393:Fish Diseases / Q000382:microbiology; D005399:Fishes / Q000382:microbiology; D005407:Flagella / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D006861:Hydrogen Peroxide / Q000494:pharmacology; D009997:Osmotic Pressure; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D012808:Sigma Factor / Q000235:genetics* / Q000378:metabolism; D013312:Stress, Physiological; D014158:Transcription, Genetic; D014774:Virulence
chemical_list: D000143:Acids; D020033:Protein Isoforms; D012808:Sigma Factor; D006861:Hydrogen Peroxide
keywords: Edwardsiella tarda EIB202; Housekeeping genes; Stress tolerance; Virulence; rpoN rpoS