Leuconostoc falkenbergense sp. nov., isolated from a lactic culture, fermentating string beans and traditional yogurt.

Abstract

In the present study, the taxonomic positions of five strains (C, 17-2, LMG 10779T, LMG 18969 and LMG 11483) of Leuconostoc pseudomesenteroides were re-evaluated by a polyphasic approach, including the analyses of 16S rRNA, pheS and rpoA gene sequences, cellular fatty acids, average nucleotide and amino acid identities (ANI and AAI), digital DNA-DNA hybridization (dDDH), and phenotypic features. Based on rpoA sequence analysis, the five strains and L. pseudomesenteroides LMG 11482T were divided into two groups: strains C, LMG 10779T and LMG 18969; strains 17-2, LMG 11483 and LMG 11482T. Each of the two groups had almost identical rpoA sequences. The rpoA sequence similarity between strain LMG 10779T and L. pseudomesenteroides LMG 11482T was 95.6 %. Strains LMG 11483 and 17-2 had 98.1 and 97.2 % ANI values, 83.5 and 73.2 % dDDH values, and a 97.0 % AAI value with L. pseudomesenteroides LMG 11482T, greater than the threshold for species demarcation, indicating that strains LMG 11483 and 17-2 belong to L. pseudomesenteroides. Strains LMG 18969 and C shared 97.1 and 98.2 % ANI values, 73.4 and 83.2 % dDDH values, and 96.9 and 96.6 % AAI values with strain LMG 10779T, greater than the threshold for species demarcation, indicating that strains LMG 10779T, LMG 18969 and C represent the same species. The ANI, dDDH and AAI values between strain LMG 10779T and the type strains of phylogenetically related species were 75.2-92.5, 20.0-48.2 and 75.3-93.9 %, respectively, below the thresholds for species demarcation, indicating that strain LMG 10779T represents a novel species within the genus Leuconostoc. On the basis of the results presented here, (i) strains 17-2 and LMG 11483 belong to L. pseudomesenteroides, and (ii) strains LMG 10779T, LMG 18969 and C are considered to represent a novel species within the genus Leuconostoc, for which the name Leuconostoc falkenbergense sp. nov. is proposed with the type strain LMG 10779T (=CCUG 27119T).