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Overexpression of mltA in Edwardsiella tarda reduces resistance to antibiotics and enhances lethality in zebra fish
Author(s) -
Liu W.,
Dong N.,
Zhang X.H.
Publication year - 2012
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1111/j.1365-2672.2012.05291.x
Subject(s) - edwardsiella tarda , microbiology and biotechnology , biology , autolysis (biology) , virulence , mutant , pathogen , lytic cycle , plasmid , bacteria , gene , virology , genetics , biochemistry , enzyme , virus
Aims: The aim of this study was to investigate the role of membrane‐bound lytic murein transglycosylase A (MltA) in a bacterial fish pathogen Edwardsiella tarda . Methods and Results: An mltA in‐frame deletion mutant (Δ mltA ) and an mltA overexpression strain ( mltA + ) of Edw. tarda were constructed through double‐crossover allelic exchange and by transformation of a low‐copy plasmid carrying the intact mltA into the Δ mltA mutant, respectively. Either inactivation or overexpression of MltA in Edw. tarda resulted in elevated sensitivity to β‐lactam antibiotics and lower viability in oligotrophic or high osmotic environment than wild‐type strain. Autolysis induced by EDTA was reduced in Δ mltA strain, while mltA + strain was virtually flimsy, indicating that MltA is responsible for the lysis effect. Moreover, mltA + strain exhibited significant increases in lipopolysaccharide (LPS) biosynthesis and virulence to zebra fish compared with wild‐type strain. Conclusions: The results indicated that MltA plays essential roles in β‐lactam antibiotics and environmental stresses resistance, autolysis, LPS biosynthesis and pathogenicity of Edw. tarda . This is the first report that MltA has a virulence‐related function in Edw. tarda . Significance and Impact of the Study: This study provided useful information for further studies on pathogenesis of Edw. tarda .