Identification of qseEGF genetic locus and its roles in controlling hemolytic activity and invasion in fish pathogen Edwardsiella tarda.
OBJECTIVE
The aims of this study were to reveal the roles of the gene locus qseEGF in the pathogenesis of Edwardsiella tarda.


RESULTS
Genome sequencing of fish pathogen E. tarda EIB202 reveals that the gene locus qseEGF, which encodes a novel two-component system QseEF, were located in E. tarda. The transcription of qseE, qseF and qseG was firstly characterized to be cotranscribed by reverse-transcribed PCR (RT-PCR). The mutant strains ΔqseE, ΔqseF and ΔqseG were constructed with in-frame deletion strategy. Compared with the wild type, all of the mutants showed attenuated virulence and impaired intracellular survival capabilities. Deletion in qseE, qseF and qseG resulted in different effects on hemolysin production in E. tarda. qRT-PCR results indicated that QseEF played a role in regulation of secretion systems, which in turn affected the virulence of E. tarda.


CONCLUSIONS
The results manifested that QseEF system affected the virulence in E. tarda EIB202 by controlling the secretion system and hemolysin production. QseE, QseG and QseF in E. tarda serve for the physiological fitness and pathogenesis related to the bacterial survival in macrophage and in vivo of fish.


CONCLUSIONS
The present results suggested that the important role of two-component system QseEF in regulation of E. tarda pathogenesis and its potential for attenuated live vaccine construction.
State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.
Jingfan
J
Xiao
Tao
T
Chen
Minjun
M
Yang
Yuanxing
Y
Zhang
Qiyao
Q
Wang
D000818:Animals; D002460:Cell Line; D020609:Edwardsiella tarda / Q000235:genetics* / Q000276:immunology / Q000472:pathogenicity*; D004756:Enterobacteriaceae Infections / Q000382:microbiology / Q000662:veterinary*; D005393:Fish Diseases / Q000382:microbiology*; D006460:Hemolysin Proteins / Q000235:genetics; D008264:Macrophages / Q000382:microbiology; D051379:Mice; D014774:Virulence; D015027:Zebrafish
D006460:Hemolysin Proteins