Comparative genome analysis ofLactobacillus mudanjiangensis, an understudied member of theLactobacillus plantarumgroup

Abstract

AbstractThe genusLactobacillusis known to be extremely diverse and consists of different phylogenetic groups that show a diversity roughly equal to the expected diversity of a typical bacterial genus. One of the most prominent phylogenetic groups within this genus is theLactobacillus plantarumgroup which contains the understudiedLactobacillus mudanjiangensisspecies. Before this study, only oneL. mudanjiangensisstrain, DSM 28402T, was described but without whole-genome analysis. In this study, three strains classified asL. mudanjiangensis, were isolated from three different carrot juice fermentations and their whole-genome sequence was determined, together with the genome sequence of the type strain. The genomes of all four strains were compared with publicly availableL. plantarumgroup genome sequences. This analysis showed thatL. mudanjiangensisharbored the second largest genome size and gene count of the wholeL. plantarumgroup. In addition, all members of this species showed the presence of a gene coding for a putative cellulose-degrading enzyme. Finally, three of the fourL. mudanjiangensisstrains studied showed the presence of pili on scanning electron microscopy (SEM) images, which were linked to conjugative gene regions, coded on plasmids in at least two of the strains studied.Author summaryLactobacillus mudanjiangensisis an understudied species within theLactobacillus plantarumgroup. Since its first description, no other studies have reported its isolation. Here, we present the first four genome sequences of this species, which include the genome sequence of the type strain and three newL. mudanjiangensisstrains isolated from fermented carrot juice. The genomes of all four strains were compared with publicly availableL. plantarumgroup genome sequences. We found that this species harbored the second largest genome size and gene count of the wholeL. plantarumgroup. Furthermore, we present the first scanning electron microscopy (SEM) images ofL. mudanjiangensis, which showed the formation of pili in three strains that we linked to genes related to conjugation. Finally, we found the presence of a unique putative cellulose-degrading enzyme, opening the door for different industrial applications of theseLactobacillusstrains.