Construction and optimization of Lactobacillus plantarum expression system expressing glycoprotein 5 of porcine reproductive and respiratory syndrome virus

Porcine reproductive and respiratory syndrome virus (PRRSV) causes serious reproductive failure and respiratory disease in pigs. Although numerous vaccines were developed against the virus, licensed vaccines showed limited efficacy. Here, we describe the construction and optimization of Lactobacillus plantarum expression system of PRRSV GP5 gene. The wild-type truncated GP5 or codon-optimized truncated GP5 was linked with endogenous signal peptide and target peptides (DCpep or Mpep) at 5′ and 3′ end of the gene, respectively. Then, the fragments were cloned into the L. plantarum expression plasmid pSIP411 and expressed under the induction of SppIP. As a result, PRRSV GP5 genes with optimized codons have higher expressions than that of the GP5 genes with wild-type codons, indicating codons optimization is an effective way to enhance the expression of an exogenous gene in L. plantarum. Further analysis showed that the codon-optimized GP5 with endogenous signal peptide can be effectively displayed on the surface of the L. plantarum, and the GP5 harboring target peptide Mpep displayed the highest antigenicity than the others. The highest production of PRRSV GP5 was obtained under the following conditions: L. plantarum harboring the plasmid pSIP-1320-O5MH are induced with 200 ng/mL SppIP at 33 °C for 7 h.