Characterization of prophages containing evolved Dit/Tal modules in the genome of Lactobacillus casei BL23

MARIA EUGENIA DIETERLE; JOAQUINA FINA MARTÍN; ROSARIO DURÁN ; SERGIO NEMIROVSKY; CARMEN SANCHEZ RIVAS; CHARLES BOWMAN; DANIEL RUSSELL; GRAHAM HATFULL; CHRISTIAN CAMBILLAU; MARIANA PIURI

APPLIED MICROBIOLOGY AND BIOTECHNOLOGY

SPRINGER

Lugar: Berlin; Año: 2016 vol. 100 p. 9201 - 9215

0175-7598

Lactic acid bacteria (LAB) have manyapplications in food and industrial fermentations. Prophage induction andgeneration of new virulent phages is a risk for the dairy industry. We identifiedthree complete prophages (PLE1, PLE2 and PLE3) in the genome of the wellstudied probiotic strain Lactobacilluscasei BL23. All of them have mosaic architectures with homologous sequencesto Streptococcus, Lactococcus, Lactobacillus and Listeria phages or strains. Using a combination ofquantitative real time PCR, genomics and proteomics we showed that PLE2 andPLE3 can be induced ? but with different kinetics ? in the presence of mitomycinC, although PLE1 remains as a prophage. A structural analysis of the distal tail (Dit) and tail associated lysin(Tal) baseplate proteins of these prophages and other L. casei/paracasei phages and prophages provides evidence that carbohydratebinding modules (CBM) located within these ?evolved? proteins may replacereceptor binding proteins (RBPs) present in other well studied LAB phages. Thedetailed study of prophage induction in this prototype strain in combinationwith characterization of the proteins involved in host recognition will facilitatethe design of new strategies for avoiding phage propagation in the dairyindustry