Multilocus sequence typing reveals a novel subspeciation of Lactobacillus delbrueckii

Abstract

Currently, the species Lactobacillus delbrueckii is divided into four subspecies, L. delbrueckii subsp. delbrueckii, L. delbrueckii subsp. bulgaricus, L. delbrueckii subsp. indicus and L. delbrueckii subsp. lactis. These classifications were based mainly on phenotypic identification methods and few studies have used genotypic identification methods. As a result, these subspecies have not yet been reliably delineated. In this study, the four subspecies of L. delbrueckii were discriminated by phenotype and by genotypic identification [amplified-fragment length polymorphism (AFLP) and multilocus sequence typing (MLST)] methods. The MLST method developed here was based on the analysis of seven housekeeping genes (fusA, gyrB, hsp60, ileS, pyrG, recA and recG). The MLST method had good discriminatory ability: the 41 strains of L. delbrueckii examined were divided into 34 sequence types, with 29 sequence types represented by only a single strain. The sequence types were divided into eight groups. These groups could be discriminated as representing different subspecies. The results of the AFLP and MLST analyses were consistent. The type strain of L. delbrueckii subsp. delbrueckii, YIT 0080 T , was clearly discriminated from the other strains currently classified as members of this subspecies, which were located close to strains of L. delbrueckii subsp. lactis. The MLST scheme developed in this study should be a useful tool for the identification of strains of L. delbrueckii to the subspecies level.

Lactobacillus delbrueckii subsp. jakobsenii subsp. nov., isolated from dolo wort, an alcoholic fermented beverage in Burkina Faso

“…sunkii, which were isolated from non-dairy based products, are lactosenegative indicating niche-associated carbohydrate fermentation phenotypes among these subspecies. Different molecular methods have been reported for identification of subspecies of L. delbrueckii (Cebeci & Gürakan, 2011;Gatti et al, 2001;Naser et al, 2007;Tanigawa & Watanabe, 2011;Torriani et al, 1999). Among these methods, multilocus sequence typing (MLST) has been indicated to offer the most successful way of discriminating between the different subspecies of L. delbrueckii (Tanigawa & Watanabe, 2011).…”

“…The length and accession numbers of all the sequences except for those of strain T were reported by Tanigawa & Watanabe (2011) and Kudo et al (2012). The sequences were manually concatenated and aligned using CLC Genomics Workbench.…”

“…Sequences of the seven housekeeping genes: ATP-dependent DNA helicase (recG), heat-shock protein 60 (hsp60), recombinase A (recA), CTP synthase (pyrG), DNA gyrase subunit B (gyrB), protein elongation factor EF-2 (fusA) and isoleucyl-tRNA synthase (ileS) used for MLST analysis of L. delbrueckii strains by Tanigawa & Watanabe (2011) were retrieved from the draft genome sequence of strain T by alignment with reference sequences using Vector NTI software v. 9.1.0. Those of 41 additional strains within the The type strain, ZN7a-9 T (5DSM 26046 T 5LMG 27067 T ), was isolated from malted sorghum wort in Burkina Faso.…”

“…Adimpong and others L. delbrueckii taxon reported by Tanigawa & Watanabe (2011) and Kudo et al (2012) were retrieved from the NCBI database (http://www.ncbi.nlm.nih.org). The length and accession numbers of all the sequences except for those of strain T were reported by Tanigawa & Watanabe (2011) and Kudo et al (2012).…”

Development of a multilocus sequence typing scheme for Streptococcus gallolyticus

“…Campylobacter fetus (van Bergen et al, 2005), Lactobacillus delbrueckii (Tanigawa & Watanabe, 2011)]. In this study, MLST clusters A, C and E consisted of S. gallolyticus subsp.…”