Limosilactobacillus reuteri, 2021

Li, Fuyong, Cheng, Christopher C., Zheng, Jinshui, Liu, Junhong, Quevedo, Rodrigo Margain, Li, Junjie, Roos, Stefan, Gänzle, Michael G. & Walter, Jens, 2021, Limosilactobacillus balticus sp. nov., Limosilactobacillus agrestis sp. nov., Limosilactobacillus albertensis sp. nov., Limosilactobacillus rudii sp. nov. and Limosilactobacillus fastidiosus sp. nov., five novel Limosilactobacillus species isolated from the vertebrate gastrointestinal tract, and proposal of six subspecies of Limosilactobacillus reuteri adapted to the gastrointestinal tract of specific vertebrate hosts, International Journal of Systematic and Evolutionary Microbiology (004644) 71 (2), pp. 1-21 : 19

DESCRIPTION OF LIMOSILACTOBACILLUS REUTERI SUBSP. SUIS SUBSP. NOV.

Limosilactobacillus reuteri subsp. suis (su′ is. L. gen. n. suis, of swine, reflecting the host origin of most strains of this subspecies being the swine intestinal tract).

L. reuteri strains clustered in lineage IV ( Fig. 3 ) belong to L. reuteri subsp. porcinus and were isolated from pig [ 5, 7]. Strains belonging to this subspecies have ANI values of 98.7–99.5% with each other and ANI values of 94.6–96.3% with other L. reuteri strains belonging to different subspecies ( Fig. 4 ). Acid is produced from L-arabinose, D-ribose, D-xylose, D-galactose, D-glucose, maltose, lactose, melibiose, sucrose and raffinose; acid is not produced from D-fructose, D-mannose, methyl α- D-glucopyranoside, aesculin, potassium gluconate, glycerol, erythritol, D-arabinose, L-xylose, D-adonitol, methyl β -D-xylopyranoside, L-sorbose, L-rhamnose, dulcitol, inositol, D-mannitol, D-sorbitol, methyl α- Dmannopyranoside, N -acetylglucosamine, amygdalin, arbutin, salicin, cellobiose, trehalose, inulin, melezitose, starch, glycogen, xylitol, gentiobiose, turanose, D-lyxose, D-tagatose, D-fucose, L-fucose, D-arabitol, L-arabitol, potassium 2-ketogluconate or potassium 5-ketogluconate. Phylogenetic analyses based on the core genes identified in this study ( Fig. 3 ) and previous studies [ 5, 43, 46, 47], AFLP and MLSA (using concatenated sequences of ddl, pkt, leuS, gyrB, dltA, rpoA and recA genes) [ 7] indicate that strains clustered in this lineage are pig-specific. A mucus-binding protein (Mub) that could bind mucus and/or IgA [ 8, 41, 42] exists within this subspecies and it specifically supports the colonization of this subspecies to the porcine gastrointestinal tract. Strains within this subspecies have been applied as probiotics to improve porcine intestinal health, enhance production, prevent diarrhoea, release stress and immune modulation [ 48].

The type strain, ATCC 53608 T (=LMG 31752 T =1063 T [original designation]), was isolated from porcine gastrointestinal tract [ 7, 49, 50], with a DNA G+C content of 39.0mol%.

Figures

Fig. 3. A maximum-likelihood phylogenetic tree reconstructed using core genes (n=100) identified from whole-genome sequences, showing the evolutionary relationships among six L. reuteri subspecies.The tree was reconstructed using 33 L. reuteri genomes available in public databases (n=6 for L. reuteri subsp. kinnaridis, n=2 for L. reuteri subsp. porcinus, n=5 for L. reuteri subsp. murium, n=10 for L. reuteri subsp. reuteri, n=5 for L. reuteri subsp. suis and n=5 for L. reuteri subsp. rodentium) and L. balticus BG-AF3-AT was used as an outgroup. Further information on the involved genome sequences is listed in Table S1. The tree was inferred based on the GTR+G model with 1000 bootstrap replicates and only bootstrap values above 60% are shown. The tree was drawn with iTOL [54].

Fig. 4. Pairwise average nucleotide identity values (ANI; %) of genome sequences belonging to the same or different L. reuteri subspecies. ANI values within the same subspecies and between different subspecies were calculated for 33 L. reuteri genomes available in public databases (n=6 for L. reuteri subsp. kinnaridis, n=2 for L. reuteri subsp. porcinus, n=5 for L. reuteri subsp.murium, n=10for L. reuteri subsp.reuteri, n=5 for L. reuteri subsp. suis and n=5 for L. reuteri subsp. rodentium). Further information on the involved genome sequences is listed in Table S1.