Authors
Liu, M., Tian, E., Cui, X., Liu, K., Feng, L., Liu, Y., Wang, Y., Shi, X., Chen, L., Hao, M.
Abstract
Precise genome editing in Enterobacteriaceae is essential for studying gene function, pathogenesis, and antimicrobial resistance, yet many current systems face host-specific and efficiency limitations. We developed pGGTOX, a modular plasmid platform that enables efficient homologous recombination-mediated genome editing across diverse Enterobacteriaceae, including Escherichia coli, Klebsiella pneumoniae, Salmonella enterica, and Enterobacter intestinihominis. The system integrates a rhamnose-inducible toxin (MqsR) for stringent counterselection, a sfGFP reporter for visual tracking of recombination events, Golden Gate cloning for rapid assembly of homologous arms, an FRT-flanked resistance cassette for marker removal, and an oriT sequence for conjugative transfer. Together with the companion plasmid pCP20-oriT, pGGTOX supports precise, marker-free genomic modification. Using pGGTOX, we achieved targeted deletions of dapA in E. coli and mrkCD in carbapenem-resistant K. pneumoniae, both with 100% efficiency. The dapA mutant exhibited diaminopimelate auxotrophy, while mrkCD deletion markedly reduced biofilm formation, consistent with the loss of function associated with these genes. pGGTOX also enabled deletion of a 43.1-kb type IV secretion gene cluster (tra) from an IncN/FII plasmid in E. intestinihominis and insertion of a 10-kb CRISPR-Cas9 plasmid-curing module (pCasCure) into an S. enterica IncX1 plasmid. Deletion of the tra gene cluster resulted in a substantial reduction in plasmid conjugation efficiency. Conjugative transfer of the engineered IncX1-pCasCure plasmid into K. pneumoniae facilitated CRISPR-mediated curing of blaKPC, sensitizing carbapenem resistance to susceptibility. In summary, pGGTOX provides a versatile, efficient, and broadly applicable platform for genome engineering and CRISPR delivery in Enterobacteriaceae, expanding the toolkit for bacterial genetics and translational antimicrobial research.
Preprint server:
bioRxiv
The authors list and abstract were imported from bioRxiv on 12 Nov 2025.
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