title: Genetic diversity and population structure of Lactobacillus delbrueckii subspecies bulgaricus isolated from naturally fermented dairy foods.
abstract: Lactobacillus delbrueckii subsp. bulgaricus is one of the most widely used starter culture strains in industrial fermented dairy manufacture. It is also common in naturally fermented dairy foods made using traditional methods. The subsp. bulgaricus strains found in naturally fermented foods may be useful for improving current industrial starter cultures; however, little is known regarding its genetic diversity and population structure. Here, a collection of 298 L. delbrueckii strains from naturally fermented products in Mongolia, Russia, and West China was analyzed by multi-locus sequence typing based on eight conserved genes. The 251 confirmed subsp. bulgaricus strains produced 106 unique sequence types, the majority of which were assigned to five clonal complexes (CCs). The geographical distribution of CCs was uneven, with CC1 dominated by Mongolian and Russian isolates, and CC2-CC5 isolates exclusively from Xinjiang, China. Population structure analysis suggested six lineages, L1-L6, with various homologous recombination rates. Although L2-L5 were mainly restricted within specific regions, strains belonging to L1 and L6 were observed in diverse regions, suggesting historical transmission events. These results greatly enhance our knowledge of the population diversity of subsp. bulgaricus strains, and suggest that strains from CC1 and L4 may be useful as starter strains in industrial fermentation.
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of China, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China.
authors.forename: Yuqin
authors.initials: Y
authors.lastname: Song
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of China, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Sun
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Chenyi
authors.initials: C
authors.lastname: Guo
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Yarong
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of China, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China.
authors.forename: Wenjun
authors.initials: W
authors.lastname: Liu
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of China, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Yu
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of China, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China.
authors.forename: Bilige
authors.initials: B
authors.lastname: Menghe
authors.affiliation: State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China.
authors.forename: Ruifu
authors.initials: R
authors.lastname: Yang
authors.affiliation: Key Laboratory of Dairy Biotechnology and Engineering, Education Ministry of China, Inner Mongolia Agricultural University, Hohhot, Inner Mongolia 010018, China.
authors.forename: Heping
authors.initials: H
authors.lastname: Zhang
mesh_terms: D058448:Biota; D002681:China; D005516:Food Microbiology; D014644:Genetic Variation; D005838:Genotype; D048668:Lactobacillus delbrueckii / Q000145:classification* / Q000235:genetics* / Q000302:isolation & purification; D008986:Mongolia; D058885:Multilocus Sequence Typing; D058974:Phylogeography; D012426:Russia; D017422:Sequence Analysis, DNA