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Int J Food Microbiol

Title:		The large plasmidome of Lactococcus lactis subsp. lactis bv. diacetylactis S50 confers its biotechnological properties
Author(s):		Malesevic M; Stanisavljevic N; Miljkovic M; Jovcic B; Filipic B; Studholme DJ; Kojic M;
Address:		"Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia. Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia; Faculty of Biology, University of Belgrade, Belgrade, Serbia. Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia; Faculty of Pharmacy, University of Belgrade, Belgrade, Serbia. Biosciences, College of Life and Environmental Sciences, University of Exeter, Stocker Road, Exeter, EX4 4QD, UK. Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, Belgrade, Serbia. Electronic address: mkojic@imgge.bg.ac.rs"
Journal Title:		Int J Food Microbiol
Year:		2021
Volume:		20201029
Issue:
Page Number:		108935 -
DOI:		10.1016/j.ijfoodmicro.2020.108935
ISSN/ISBN:		1879-3460 (Electronic) 0168-1605 (Linking)
Abstract:		"Plasmids are autonomous episomally replicating genetic elements, which carry backbone genes important for the replication and maintenance within their host, and accessory genes that might confer an advantage to their host under specific selective pressure in its ecological niche. The genome of dairy isolate L. lactis subsp. lactis bv. diacetylactis S50 was sequenced using the PacBio SMRT Cell Seq-RSII platform and revealed to possess one of the largest plasmidomes among L. lactis strains studied so far, harboring six plasmids: pS6 (5553 bp), pS7a (7308 bp), pS7b (7266 bp), pS19 (19,027 bp), pS74 (74,256 bp) and pS127 (127,002 bp) in total representing 8.9% of genome size (240,412 bp). Based on predicted plasmid replication proteins and origins it appears that all six plasmids replicate via the theta-type mechanism. The two the largest plasmids (pS74 and pS127), carry a number of genes known to be important for growth and survival in the dairy environment. These genes encode technological functions such as bacteriocin production, protein degradation, magnesium and cobalt/nickel transporters, selenium binding, exopolysaccharides (EPS) production, bacteriophage and stress resistance. Beside genes for replication, the small plasmids (pS6, pS7a, pS7a, and pS19) also carry genes important for mobilization and host survival such as type I restriction-modification (R-M) system, metal transporters, enzymes and transcriptional regulators. All plasmids in S50 strain are mobilizable, containing an oriT sequences, while pS127 is self-conjugative and allows for mobilization of the other plasmids. Small plasmids are prone to structural and segregational instability, while pS127 appeared to be segregationally stable thanks to the possession of two partition systems. The main characteristic of plasmid pS74 is EPS production, while plasmid pS127 is characterized by proteinase and multiple bacteriocins, tra locus, phage abortive systems and metal transporters. In addition to LcnA and LcnB, plasmid pS127 encodes several bacteriocin-pheromone molecules and a new bacteriocin named LcnS50, with narrow spectrum of action limited to lactococci, that has been successfully cloned and heterologously expressed"
Keywords:		Bacteriocin Plasmids/*genetics Bacteriocins/*genetics *Biotechnology Industrial Microbiology Lactococcus lactis/*genetics Bacteriocins Dairy important features EPS production Fitness Mobilization Plasmidome;
Notes:		"MedlineMalesevic, Milka Stanisavljevic, Nemanja Miljkovic, Marija Jovcic, Branko Filipic, Brankica Studholme, David J Kojic, Milan eng Netherlands 2020/11/06 Int J Food Microbiol. 2021 Jan 16; 337:108935. doi: 10.1016/j.ijfoodmicro.2020.108935. Epub 2020 Oct 29"