Catalogue of surface proteins of Lactiplantibacillus plantarum strains of dairy and vegetable niches.

Lactiplantibacillus plantarum (formerly Lactobacillus plantarum) exhibits relevant probiotic and technological features and is widely used in food industries, improving flavour, texture and organoleptic properties of fermented products. Cell-surface proteins have a key role in the molecular mechanisms responsible for healthy effects, being the first actors in the bacteria - host interactions. Proteins present on the surface of four L. plantarum strains (two isolated from vegetable matrices and two from dairy products) were identified by proteomics with the aim to gain a comprehensive picture of differences in protein profiles potentially related to the habitat of origin and specific properties of the analyzed strains. Results highlighted a more diversified pattern of surface proteins in strains from vegetable matrices compared to those from dairy matrices (>500 proteins vs about 200 proteins, respectively). The four strains shared a core of 143 proteins, while 445 were specifically present in strains from vegetable matrices and 26 were peculiar of strains from dairy origin. Sortase A, involved in adhesion, and choloylglycine hydrolase (bile salt hydrolase) were detected only in strains from vegetable matrices. The peculiar molecular functions of identified proteins suggested that these strains, and in particular L. plantarum S61, could have a significant probiotic and biotechnological potential.