Construction of Non-Antibiotic Resistance Expression Vector by Secretory <i>β-Gal</i> as a Selective Marker in <i>Lactobacillus</i>

On account of the spreading problem of resistance gene and off-target effects of functional gene products expressed by bacteria, pMG36e, a plasmid with the erythromycin- resistance (Emr) gene, which could shuttle between Lactobacillus and E. coli, was reconstructed into a non-antibiotic secretory expression vector with the beta-Galactosidase (β-Gal) gene for selection, then linked a secretory signal peptide sequence to the non-antibiotic resistance vector, thus the secretory non-antibiotic resistance vector was constructed. Finally, to test the vector's function, the SO7 gene of Eimeria tenella (E. tenella) was cloned into the vector and expressed successfully. This system may be used as a model to explore the feasibility of vaccine vectors using the β-Gal gene for selection, and collect fundamental data for expressing other homogeneous and heterogeneous functional genes in such a novel vector.