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Zheng J, Wittouck S, Salvetti E, Franz CMAP, Harris HMB, Mattarelli P, O'Toole PW, Pot B, Vandamme P, Walter J, Watanabe K, Wuyts S, Felis GE, Gänzle MG, Lebeer S. A taxonomic note on the genus Lactobacillus: Description of 23 novel genera, emended description of the genus Lactobacillus Beijerinck 1901, and union of Lactobacillaceae and Leuconostocaceae. Int J Syst Evol Microbiol 2020; 70:2782-2858. [PMID: 32293557 DOI: 10.1099/ijsem.0.004107] [Citation(s) in RCA: 1565] [Impact Index Per Article: 391.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The genus Lactobacillus comprises 261 species (at March 2020) that are extremely diverse at phenotypic, ecological and genotypic levels. This study evaluated the taxonomy of Lactobacillaceae and Leuconostocaceae on the basis of whole genome sequences. Parameters that were evaluated included core genome phylogeny, (conserved) pairwise average amino acid identity, clade-specific signature genes, physiological criteria and the ecology of the organisms. Based on this polyphasic approach, we propose reclassification of the genus Lactobacillus into 25 genera including the emended genus Lactobacillus, which includes host-adapted organisms that have been referred to as the Lactobacillus delbrueckii group, Paralactobacillus and 23 novel genera for which the names Holzapfelia, Amylolactobacillus, Bombilactobacillus, Companilactobacillus, Lapidilactobacillus, Agrilactobacillus, Schleiferilactobacillus, Loigolactobacilus, Lacticaseibacillus, Latilactobacillus, Dellaglioa, Liquorilactobacillus, Ligilactobacillus, Lactiplantibacillus, Furfurilactobacillus, Paucilactobacillus, Limosilactobacillus, Fructilactobacillus, Acetilactobacillus, Apilactobacillus, Levilactobacillus, Secundilactobacillus and Lentilactobacillus are proposed. We also propose to emend the description of the family Lactobacillaceae to include all genera that were previously included in families Lactobacillaceae and Leuconostocaceae. The generic term 'lactobacilli' will remain useful to designate all organisms that were classified as Lactobacillaceae until 2020. This reclassification reflects the phylogenetic position of the micro-organisms, and groups lactobacilli into robust clades with shared ecological and metabolic properties, as exemplified for the emended genus Lactobacillus encompassing species adapted to vertebrates (such as Lactobacillus delbrueckii, Lactobacillus iners, Lactobacillus crispatus, Lactobacillus jensensii, Lactobacillus johnsonii and Lactobacillus acidophilus) or invertebrates (such as Lactobacillus apis and Lactobacillus bombicola).
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Affiliation(s)
- Jinshui Zheng
- Huazhong Agricultural University, State Key Laboratory of Agricultural Microbiology, Hubei Key Laboratory of Agricultural Bioinformatics, Wuhan, Hubei, PR China
| | - Stijn Wittouck
- Research Group Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | - Elisa Salvetti
- Dept. of Biotechnology, University of Verona, Verona, Italy
| | - Charles M A P Franz
- Max Rubner-Institut, Department of Microbiology and Biotechnology, Kiel, Germany
| | - Hugh M B Harris
- School of Microbiology & APC Microbiome Ireland, University College Cork, Co. Cork, Ireland
| | - Paola Mattarelli
- University of Bologna, Dept. of Agricultural and Food Sciences, Bologna, Italy
| | - Paul W O'Toole
- School of Microbiology & APC Microbiome Ireland, University College Cork, Co. Cork, Ireland
| | - Bruno Pot
- Research Group of Industrial Microbiology and Food Biotechnology (IMDO), Vrije Universiteit Brussel, Brussels, Belgium
| | - Peter Vandamme
- Laboratory of Microbiology, Department of Biochemistry and Microbiology, Ghent University, Ghent, Belgium
| | - Jens Walter
- Department of Biological Sciences, University of Alberta, Edmonton, Canada.,Department of Agricultural, Food & Nutritional Science, University of Alberta, Edmonton, Canada
| | - Koichi Watanabe
- Food Industry Research and Development Institute, Bioresource Collection and Research Center, Hsinchu, Taiwan, ROC.,National Taiwan University, Dept. of Animal Science and Technology, Taipei, Taiwan, ROC
| | - Sander Wuyts
- Research Group Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
| | | | - Michael G Gänzle
- Hubei University of Technology, College of Bioengineering and Food Science, Wuhan, Hubei, PR China.,Department of Agricultural, Food & Nutritional Science, University of Alberta, Edmonton, Canada
| | - Sarah Lebeer
- Research Group Environmental Ecology and Applied Microbiology, Department of Bioscience Engineering, University of Antwerp, Antwerp, Belgium
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Comparative genomics of Lactobacillus species as bee symbionts and description of Lactobacillus bombintestini sp. nov., isolated from the gut of Bombus ignitus. J Microbiol 2020; 58:445-455. [PMID: 32222941 DOI: 10.1007/s12275-020-9596-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2019] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 12/18/2022]
Abstract
The Lactobacillus genus is widely used for fermentation of plant materials and dairy products. These species are typically found in highly specialized environments, with the bee gut serving as one of the niche locations in which Lactobacillus is detected. Lactobacillus species isolated from the bee gut and bee-related habitats were phylogenetically classified into three distinct groups, Lactobacillus kunkeei, Firm-4, and Firm-5. The L. kunkeei group was clearly differentiated from other members of the Lactobacillus buchneri group isolated from non-bee habitats. In comparison with non-bee members of the L. buchneri group, three bee-symbiotic Lactobacillus groups had a small-sized genome with low G + C content and showed a sharp reduction in the number of genes involved in energy production, carbohydrate transport and metabolism, and amino acid transport and metabolism. In addition, all three groups lacked the mutY gene, which encodes A/G-specific adenine glycosylase. The phylogenetic dendrogram based on the presence or absence of 1,199 functional genes indicated that these bee-symbiotic groups experienced convergent evolution. The occurrence of convergent evolution is thought to stem from the three bee-symbiotic groups sharing a similar habitat, i.e., the bee gut. The causative factor underlying genomic reduction was postulated to be mutY, which was absent in all three groups. Here, a novel strain, BHWM-4T, isolated from the gut of Bombus ignites was studied using polyphasic taxonomy and classified as a new member of the L. kunkeei group. The strain was Gram-positive, facultative anaerobic, and rod-shaped. The 16S ribosomal RNA gene sequence and genome analysis revealed that strain BHWM-4T was clustered into the L. kunkeei group, forming a compact cluster with L. kunkeei and Lactobacillus apinorum. Biochemical, chemotaxonomic, and genotypic data of strain BHWM-4T supports the proposal of a novel species, Lactobacillus bombintestini sp. nov., whose type strain is BHWM-4T (= KACC 19317 = NBRC 113067T).
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Abstract
The Lactobacillus genus complex is a group of bacteria that constitutes an important source of strains with medical and food applications. The number of bacterial whole-genome sequences available for this taxon has been increasing rapidly in recent years. Despite this wealth of information, the species within this group are still largely defined by older techniques. Here, we constructed a completely new species-level taxonomy for the Lactobacillus genus complex based on ∼2,500 whole-genome sequences. As a result of this effort, we found that many genomes are not classified to their correct species, and we were able to correct these. In addition, we found that some published species are abnormally large, while others are too small. Finally, we discovered at least eight completely novel species that have not been published before. Our work will help the field to evolve toward a more meaningful and complete taxonomy, based on whole-genome sequences. There are more than 200 published species within the Lactobacillus genus complex (LGC), the majority of which have sequenced type strain genomes available. Although genome-based species delimitation cutoffs are accepted as the gold standard by the community, these are seldom actually checked for new or already published species. In addition, the availability of genome data is revealing inconsistencies in the species-level classification of many strains. We constructed a de novo species taxonomy for the LGC based on 2,459 publicly available genomes, using a 94% core nucleotide identity cutoff. We reconciled these de novo species with published species and subspecies names by (i) identifying genomes of type strains and (ii) comparing 16S rRNA genes of the genomes with 16S rRNA genes of type strains. We found that genomes within the LGC could be divided into 239 de novo species that were discontinuous and exclusive. Comparison of these de novo species to published species led to the identification of nine sets of published species that can be merged and one species that can be split. Further, we found at least eight de novo species that constitute new, unpublished species. Finally, we reclassified 74 genomes on the species level and identified for the first time the species of 98 genomes. Overall, the current state of LGC species taxonomy is largely consistent with genome-based species delimitation cutoffs. There are, however, exceptions that should be resolved to evolve toward a taxonomy where species share a consistent diversity in terms of sequence divergence. IMPORTANCE The Lactobacillus genus complex is a group of bacteria that constitutes an important source of strains with medical and food applications. The number of bacterial whole-genome sequences available for this taxon has been increasing rapidly in recent years. Despite this wealth of information, the species within this group are still largely defined by older techniques. Here, we constructed a completely new species-level taxonomy for the Lactobacillus genus complex based on ∼2,500 whole-genome sequences. As a result of this effort, we found that many genomes are not classified to their correct species, and we were able to correct these. In addition, we found that some published species are abnormally large, while others are too small. Finally, we discovered at least eight completely novel species that have not been published before. Our work will help the field to evolve toward a more meaningful and complete taxonomy, based on whole-genome sequences.
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Zhang Z, Hou Q, Wang Y, Li W, Zhao H, Sun Z, Guo Z. Lactobacillus zhachilii sp. nov., a lactic acid bacterium isolated from Zha-Chili. Int J Syst Evol Microbiol 2019; 69:2196-2201. [DOI: 10.1099/ijsem.0.003362] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Zhendong Zhang
- 1Northwest Hubei Research Institute of Traditional Fermented Food, College of Food Science and Technology, Hubei University of Arts and Science, Xiangyang, Hubei, PR China
| | - Qiangchuan Hou
- 2Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Huhhot, PR China
| | - Yurong Wang
- 1Northwest Hubei Research Institute of Traditional Fermented Food, College of Food Science and Technology, Hubei University of Arts and Science, Xiangyang, Hubei, PR China
| | - Weicheng Li
- 2Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Huhhot, PR China
| | - Huijun Zhao
- 1Northwest Hubei Research Institute of Traditional Fermented Food, College of Food Science and Technology, Hubei University of Arts and Science, Xiangyang, Hubei, PR China
| | - Zhihong Sun
- 2Key Laboratory of Dairy Biotechnology and Engineering, Ministry of Education, Key Laboratory of Dairy Products Processing, Ministry of Agriculture and Rural Affairs, Inner Mongolia Agricultural University, Huhhot, PR China
| | - Zhuang Guo
- 1Northwest Hubei Research Institute of Traditional Fermented Food, College of Food Science and Technology, Hubei University of Arts and Science, Xiangyang, Hubei, PR China
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