Selection of reference genes for gene expression studies in Lactic acid bacteria

Abstract

Lactic acid bacteria (LAB) are used to preserve meat, dairy products and fermented or raw vegetables against food-borne human pathogens. Besides, they have potential as biological control agents of plant pathogenic bacteria and fungi. The success of LAB in preventing the growth and activity of undesirable microorganisms is due to different mechanisms of action including the production of bacteriocins. Bacteriocins of LAB are antimicrobial peptides that have attracted much interest in recent years because of their suitability as food preservatives or plant bio pesticides. One of the prospects on the use of bacteriocins is the possibility of increasing its activity. The synthesis of bacteriocins is controlled by complex regulatory systems, therefore it is of great interest to study the factors affecting the expression of bacteriocin biosynthetic genes. The aim of this study was to set up a technique select the reference genes to evaluate the expression levels of some selected LAB bacteriocin genes using a biomolecular approach based on reverse transcription quantitative PCR (RT-qPCR). Specifically, the bacteriocins selected for the quantification were nisin synthesized by Lactococcus lactis and mesentericin by Leuconostoc mesenteroides. RTqPCR technique allows quantifying the transcript levels of target genes in order to study the influence of environmental conditions in the synthesis of genes. Hence, to set up the technique a reference gene (internal control gene) for the normalization of gene expression values should be selected