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Impact of co‐deficiency of RpoN and RpoS on stress tolerance, virulence and gene regulation in Edwardsiella tarda
Author(s) -
Liu Enfu,
Ye Jiang,
Song ShanShan,
Wang Keping,
Zhang Yuanxing,
Zhang Huizhan
Publication year - 2014
Publication title -
journal of basic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.58
H-Index - 54
eISSN - 1521-4028
pISSN - 0233-111X
DOI - 10.1002/jobm.201300622
Subject(s) - rpos , rpon , sigma factor , biology , edwardsiella tarda , virulence , microbiology and biotechnology , mutant , genetics , gene , gene expression , promoter
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 H 2 O 2 , 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 .