Project description:Mostly, lactic acid bacteria (LAB), including food-spoilage-associated, grow in communities consisting of several microbial species. The interspecies interactions eventually shape the structure and global activity of a given microbial community. Generally, the knowledge on system level responses of LAB (especially food-spoilage-associated) during such interactions is very limited. To study transcriptome responses during interactions between three MAP meat-spoilage-associated LAB (Leuconostoc gelidum subsp. gasicomitatum LMG 18811T, Lactococcus piscium MKFS47 and Lactobacillus oligofermentans LMG 22743T) we grew them separately in individual cultures and in mixed cultures pairwise (three combinations) and all together (triple culture) in three replicates on a glucose-containing growth medium (MRS) under microaerobic conditions at 25 C, samples were taken at three time points (3, 5 and 11 h) and extracted RNA were sequenced. The experiments were performed in two batches. At first (batch 1), co-cultivation of Le. gelidum and Lc. piscium accompanied with their individual cultures was performed and processed. The raw RNA-seq data for the individual culture of Lc. piscium from the batch 1 were uploaded earlier and are available in the ArrayExpress database under accession number E-MTAB-3245. Later (batch 2), two other pairwise cultures (Le. gelidum + Lb. oligofermentans and Lc. piscium + Lb. oligofermentans) and the triple culture were grown together with the individual cultures of all three LAB. Designations used for the sample names: G: Le. gelidum; P: Lc. piscium; O: Lb. oligofermentans; GO, PO, PG: pairwise cultures of the corresponding species; OPG: triple culture; b1: batch 1; b2: batch 2. Example: 3G2_b1: 3 h, Le. gelidum, 2nd replicate, batch 1; 11PO3_b2: 11 h, pairwise culture of Lc. piscium and Lb. oligofermentans, 3d replicate, batch 2. One sample (5PO3_b2) had very low number of reads ~ 9000, and, therefore, was not uploaded under this project. RNA extraction and library construction were done analogously as in the study (Andreevskaya M et al., 2015. Appl. Environ. Microbiol. 81:38003811, doi: 10.1128/AEM.00320-15). Ribosomal RNA was omitted. Libraries were sequenced in five lanes using SOLiD 5500XL (Life technologies, Foster City, Ca, USA) to produce 75 bp single-end reads. For the data submission, xsq files obtained from SOLiD 5500XL machine, were converted into fastq files. Adapter sequences were removed using cutadapt 1.4.1.

Project description:BackgroundLeuconostoc gelidum and Leuconostoc gasicomitatum have dual roles in foods. They may spoil cold-stored packaged foods but can also be beneficial in kimchi fermentation. The impact in food science as well as the limited number of publicly available genomes prompted us to create pangenomes and perform genomic taxonomy analyses starting from de novo sequencing of the genomes of 37 L. gelidum/L. gasicomitatum strains from our culture collection. Our aim was also to evaluate the recently proposed change in taxonomy as well as to study the genomes of strains with different lifestyles in foods.MethodsWe selected as diverse a set of strains as possible in terms of sources, previous genotyping results and geographical distribution, and included also 10 publicly available genomes in our analyses. We studied genomic taxonomy using pairwise average nucleotide identity (ANI) and calculation of digital DNA-DNA hybridisation (dDDH) scores. Phylogeny analyses were done using the core gene set of 1141 single-copy genes and a set of housekeeping genes commonly used for lactic acid bacteria. In addition, the pangenome and core genome sizes as well as some properties, such as acquired antimicrobial resistance (AMR), important due to the growth in foods, were analysed.ResultsGenome relatedness indices and phylogenetic analyses supported the recently suggested classification that restores the taxonomic position of L. gelidum subsp. gasicomitatum back to the species level as L. gasicomitatum. Genome properties, such as size and coding potential, revealed limited intraspecies variation and showed no attribution to the source of isolation. The distribution of the unique genes between species and subspecies was not associated with the previously documented lifestyle in foods. None of the strains carried any acquired AMR genes or genes associated with any known form of virulence.ConclusionGenome-wide examination of strains confirms that the proposition to restore the taxonomic position of L. gasicomitatum is justified. It further confirms that the distribution and lifestyle of L. gelidum and L. gasicomitatum in foods have not been driven by the evolution of functional and phylogenetic diversification detectable at the genome level.

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Leuconostoc gelidum JB7

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