Abstract: [Objective] To screen an enhanced expressed promoter with high stability using the known Lactobacillus plantarum promoter and the green fluorescent protein reporter gene, and to provide genetic element for construction of the highly efficient and specific expression vectors in Lactobacillus plantarum. [Method] The known Lactobacillus plantarum promoters of P11, Pefp, Ptuf33 and Ptuf34 as well as the corresponding downstream green fluorescent protein reporter genes were synthesized, respectively. To construct the promoter-screening vectors, the above synthesized sequences were used to replace the original multiple cloning sites and the corresponding upstream promoters of the pMG36e, a lactic acid bacteria expression vector, respectively. The successfully constructed promoter-screening vectors were transformed into Lactobacillus plantarum by electroporation, and the promoters were screened by detecting the strength of green fluorescent signal of recombinants. [Result] Among the four constructed promoters, Ptuf33 and Ptuf34, the promoters of transcription elongation factor TU gene, had significantly （P<0.05) higher expression levels in the target genes compared with the other two promoters. [Conclusion] In combination with the results obtained in this study and related reports, it is known that the promoters of Ptuf33 and Ptuf34 are generally highly expressed in Lactobacillus plantarum, and they can serve as the candidates for subsequent construction of highly expressed vectors in Lactobacillus plantarum.

Key words: promoter, Lactobacillus plantarum, green fluorescent protein reporter gene