Proteomics for depicting the secreted protein patterns of Lactiplantibacillus plantarum strains isolated from different food matrices

Lactiplantibacillus plantarum (formerly known as Lactobacillus plantarum), a bacterial species isolated from a wide variety of ecological niches, plays an important role in food industries, being used as a starter culture of food fermentations and contributing to improve flavor, texture, sensorial qualities, and shelf life. It also improves the nutritional and functional properties of fermented foods through the biosynthesis of bioactive compounds and several strains exhibit probiotic features. In recent years, this bacterial species has also shown great potential for controlling plant pathogenic fungi. Shotgun proteomic approach and label free quantitative analyses were used to realize a detailed catalog of the proteins secreted by five L. plantarum strains isolated from vegetable foods or dairy products and exhibiting specific function features. In particular, these strains showed in vitro inhibitory activity against bacteria and molds. Results led to identify 602 proteins differently present in the secretome of the analyzed strains. For instance, proteins of application interest such as bacteriocins, glucansucrase, glycoside hydrolase and chitin binding proteins were differentially secreted in the five strains. The information gathered in this study is a valuable contribution to increasing knowledge in relation to one of the most important bacterial species used as probiotic, for biocontrol of plant pathogenic bacteria and fungi and in different food production worldwide.