[Objective] The purpose of this study was to construct a vscC in-frame deletion mutant of Vibrio alginolyticus with no antibiotic resistance marker. [Method] The first vscC mutant molecules in vitro were generated by SOE-PCR and then lig- ated to a suicide vector pDM4 to construct a suicide recombinant vector pDM4- A vscC. To clone the recombinant vector, it was transformed to E. coli SY327 strain, and then positive clones were selected and proved by PCR analysis. After that, the pDM4-AvscC DNA was extracted in large numbers and transformed to the E. coil S17-1 strain that acted as a donor in bacterial conjugation using the heat shock method. The recombinant E. coli S17-1 strains then transferred the pDM4-AvscC to V. alginolyticus ZJ51-O by conjugation method; transconjugants were screened and selected sequentially using antibiotic selection strategy and sucrose based counter-selection system to find the suspected mutants wanted. Finally the putative mutants were identified by PCR and confirmed by sequencing analysis. [Result] ZJ51-OAvscC was successfully constructed. [Conclusion] This study laid foundation for further research on the function of vscC gene and molecular mechanism of type Ⅲ secretion system in V. alginolyticus. Simultaneously, by the effective method other unknown functional genes in V. alginolyticus genome would be researched.
