The Type Strain of Bifidobacterium indicum Scardovi and Trovatelli 1969 (Approved Lists 1980) is ATCC 25912, not DSM 20214, and Rejection to Reclassify Bifidobacterium coryneforme as Bifidobacterium indicum.

In 2018, Nouioui et al. proposed that Bifidobacterium coryneforme was a later synonym of Bifidobacterium indicum on the basis of the digital DNA-DNA hybridization (dDDH) value (85.0%) between B. coryneforme LMG 18911T and B. indicum LMG 11587T. However, in the study of Scardovi et al. (1970), the type strains of B. indicum and B. coryneforme only exhibited 60% DNA-DNA hybridization value. In the present study, the genomes of B. coryneforme CGMCC 1.2279T, B. coryneforme JCM 5819T, B. indicum JCM 1302T, B. indicum CGMCC 1.2275T, B. indicum DSM 20214T, B. indicum LMG 27437T, B. indicum ATCC 25912T, B. indicum KCTC 3230T, B. indicum CCUG 34985T, were sequenced, and the taxonomic relationship between B. coryneforme and B. indicum was re-evaluated. On the basis of the results presented here, (i) ATCC 25912 and DSM 20214 deposited by Vittorio Scardovi are two different strains; (ii) the type strain of B. indicum is ATCC 25912T (= JCM 1302T = LMG 27437T = CGMCC 1.2275T = KCTC 3230T), and not DSM 20214 (= BCRC 14674 = CCUG 34985 = LMG 11587); (iii) B. coryneforme and B. indicum represent two different species of the genus Bifidobacterium; (iv) strain DSM 20214 (= BCRC 14674 = CCUG 34985 = LMG 11587) belongs to B. coryneforme.

Bifidobacterium apis sp. nov., isolated from the gut of honeybee (Apis mellifera).

A novel bifidobacterium (designated F753-1T) was isolated from the gut of honeybee (Apis mellifera). Strain F753-1T was characterized using a polyphasic taxonomic approach. Strain F753-1T was phylogenetically related to the type strains of Bifidobacterium mizhiensis, Bifidobacterium asteroides, Bifidobacterium choladohabitans, Bifidobacterium mellis, Bifidobacterium apousia and Bifidobacterium polysaccharolyticum, having 98.4-99.8 % 16S rRNA gene sequence similarities. The phylogenomic tree indicated that strain F753-1T was most closely related to the type strains of B. mellis and B. choladohabitans. Strain F753-1T had the highest average nucleotide identity (94.1-94.5 %) and digital DNA-DNA hybridization (56.3 %) values with B. mellis Bin7NT. Acid production from amygdalin, d-fructose, gentiobiose, d-mannose, maltose, sucrose and d-xylose, activity of α-galactosidase, pyruvate utilization and hydrolysis of hippurate could differentiate strain F753-1T from B. mellis CCUG 66113T and B. choladohabitans JCM 34586T. Based upon the data obtained in the present study, a novel species, Bifidobacterium apis sp. nov., is proposed, and the type strain is F753-1T (=CCTCC AB 2023227T=JCM 36562T=LMG 33388T).

Lactiplantibacillus paraxiangfangensis sp. nov., isolated from traditional Chinese pickle.

Three Gram-stain-positive bacterial strains (designated 231-9T, 142-6 and 463-4) were isolated from traditional Chinese pickle, and were characterized using a polyphasic taxonomic approach. Results of 16S rRNA gene sequence analysis indicated that strains 231-9T, 142-6 and 463-4 were phylogenetically related to the type strains of Lactiplantibacillus xiangfangensis, Lactiplantibacillus garii, Lactiplantibacillus carotarum, Lactiplantibacillus plajomi and Lactiplantibacillus modestisalitolerans, having 98.6-99.9 % 16S rRNA gene sequence similarities. Strains 231-9T, 142-6 and 463-4 were most closely related to the type strain of L. xiangfangensis, having 99.9 % 16S rRNA gene, 95.6 % pheS, 99.4 % rpoA and 98.2 % concatenated pheS and rpoA sequence similarities. Relatively low pheS (95.6 %) sequence similarity indicated that strain 231-9T should be further identified. Strain 231-9T shared 99.7-99.9 % average nucleotide identity (ANI) and 98.8-98.9 % digital DNA-DNA hybridization (dDDH) values with strains 142-6 and 463-4, indicating that they belonged to the same species. The ANI and dDDH values between strain 231-9T and L. xiangfangensis LMG 26013T were 92.4-92.9 and 49.6 %, respectively, less than the threshold for species demarcation (95-96% ANI and 70 % dDDH values, respectively), indicating that strains 231-9T, 142-6 and 463-4 represented a novel species within the genus Lactiplantibacillus. Acid production from d-ribose, d-adonitol, d-galactose and lactose, activity of ß-galactosidase and ß-glucosidase, Voges-Proskauer reaction, hydrolysis of hippurate, resistance to 5 µg ml-1 erythromycin, 100 µg ml-1 tetracycline hydrochloride, 50 µg ml-1 bacitracin, 300 µg ml-1 each of gentamicin sulphate, streptomycin sulphate and neomycin sulphate, tolerance to 6 % NaCl could distinguish strains 231-9T, 142-6 and 463-4 from L. xiangfangensis 3.1.1T. Based upon the data of polyphasic characterization obtained in the present study, a novel species, Lactiplantibacillus paraxiangfangensis sp. nov., is proposed and the type strain is 231-9T (=JCM 36258T=CCTCC AB 2023133T).

Lactobacillus juensis sp. nov. and Lactobacillus rizhaonensis sp. nov., isolated from the gut of honeybee (Apis mellifera).

Four lactic acid bacteria, designated F690T, F697, F790T and F769-2, were isolated from the gut of honeybee (Apis mellifera). Results of 16S rRNA gene sequence analysis indicated that strains F690T and F697 were phylogenetically related to the type strains of Lactobacillus kimbladii, Lactobacillus laiwuensis, Lactobacillus kullabergensis and Lactobacillus huangpiensis, having 99.1-99.6 % 16S rRNA gene sequence similarities; and that strains F790T and F769-2 were most closely related to the type strain of Lactobacillus melliventris, having 99.2-99.3 % 16S rRNA gene sequence similarities. The phylogenies based on concatenated pheS, rpoA, gyrB, hsp60, recA, rpoB and tuf sequences and based on whole genome sequences were identical to that based on 16S rRNA gene sequences. Strains F690T and F697 exhibited the highest average nucleotide identity (ANI; 92.1-93.2 %), digital DNA-DNA hybridization (dDDH; 50-50.1 %) and average amino acid identity (AAI; 94.9-95.1 %) values with L. kimbladii Hma2NT. Strains F790T and F769-2 had the highest ANI (93.1-94 %), dDDH (54.4 %) and AAI (94.4-94.7 %) values with L. melliventris Hma8NT. Based upon the data obtained in the present study, two novel species, Lactobacillus juensis sp. nov. and Lactobacillus rizhaonensis sp. nov., are proposed and the type strains are F690T (=JCM 36259T=CCTCC AB 2023131T) and F790T (=JCM 36260T=CCTCC AB 2023132T), respectively.

Elevation of Lentilactobacillus rapi subsp. dabitei Li et al. 2022 to the species level as Lentilactobacillus dabitei sp. nov.

Lentilactobacillus rapi subsp. dabitei was proposed by Li et al. in 2022. The type strains of L. rapi subsp. dabitei and L. rapi subsp. rapi shared 93.1 % average nucleotide identity and 52.8 % digital DNA-DNA hybridization values. Strain IMAU80584T was proposed as a novel subspecies of L. rapi rather than a novel species of the genus Lentilactobacillus on the basis of similar phenotypic characteristics (including growth temperature and pH, tolerance to NaCl and features based on API 50CH and API ZYM). However, the phenotypic investigation performed by Li et al. was insufficient because some physiological and biochemical characteristics recommended by Mattarelli et al. were not included. In the present study, the taxonomic relationship between L. rapi subsp. dabitei and L. rapi subsp. rapi was re-evaluated. Based upon the data obtained in the present study, we propose to elevate L. rapi subsp. dabitei to the species level as Lentilactobacillus dabitei sp. nov. The type strain is IMAU80584T (=GDMCC 1.2566T=JCM 34647T).

Proposal to Reclassify Companilactobacillus futsaii subsp. chongqingensis as a Later Heterotypic Synonym of Companilactobacillus futsaii subsp. futsaii.

Previous studies have shown that Lactobacillus futsaii (now Companilactobacillus futsaii) can be subdivided at the subspecies level. The main purpose of this study is to explore whether this is correct by using a polyphasic taxonomic approach. Lactobacillus futsaii subsp. chongqingii was proposed and effectively published in 2019. The names L. futsaii subsp. chongqingensis corrig. and Lactobacillus futsaii subsp. futsaii were not validated until March 2023. However, in the reclassification of the genus Lactobacillus by Zheng et al. in April 2020, L. futsaii was transferred to Companilactobacillus as Companilactobacillus futsaii. So Lactobacillus futsaii subsp. chongqingensis and Lactobacillus futsaii subsp. futsaii should be transferred to Companilactobacillus futsaii now. In the present study, the relationship between L. futsaii subsp. chongqingensis and L. futsaii subsp. futsaii was re-evaluated. The type strains of L. futsaii subsp. chongqingensis and L. futsaii subsp. futsaii shared identical pheS and rpoA sequences, high dDDH value, similar phenotypic characteristics and fatty acid compositions, indicating that they belonged to the same subspecies. Here, we propose to reclassify Lactobacillus futsaii subsp. chongqingensis and Lactobacillus futsaii subsp. futsaii as Companilactobacillus futsaii subsp. chongqingensis comb. nov. and Companilactobacillus futsaii subsp. futsaii comb. nov., respectively, and Companilactobacillus futsaii subsp. chongqingensis as a later heterotypic synonym of Companilactobacillus futsaii subsp. futsaii.

Bifidobacterium mizhiense sp. nov., isolated from the gut of honeybee (Apis mellifera).

A novel bifidobacteria (designated S053-2T) was isolated from the gut of honeybee (Apis mellifera). Strain S053-2T was characterized using a polyphasic taxonomic approach. The result of 16S rRNA gene sequence analysis indicated that strain S053-2T was phylogenetically related to the type strains of Bifidobacterium asteroides, Bifidobacterium indicum, Bifidobacterium actinocoloniiforme, Bifidobacterium xylocopae, Bifidobacterium coryneforme, Bifidobacterium apousia, Bifidobacterium choladohabitans and Bifidobacterium polysaccharolyticum, and had 95.5-99.7 % 16S rRNA gene sequence similarities. Based on the 16S rRNA gene sequence analysis, strain S053-2T was most closely related to the type strain of B. asteroides, having 99.7 % 16S rRNA gene sequence similarity. Strain S053-2T had relatively low (91.6-95.7 %) pheS, atpA, clpC, dnaG, fusA, glnA, glyS, hsp60, argS, pyrG and recA sequence similarities to the type strain of B. asteroides. Strain S053-2T had 94.5-95.3% atpA, clpC, dnaG, dnaK and pyrG sequence similarities to the type strain of B. apousia. The phylogenomic tree indicated that strain S053-2T belonged to the B. asteroides group, and was most closely related to the type strains of B. asteroides, B. apousia, B. choladohabitans and B. polysaccharolyticum, and distantly related to type strains of other phylogenetically related species in the B. asteroides group. Strain S053-2T shared the highest average nucleotide identity (ANI, 93.8 %), digital DNA-DNA hybridization (dDDH, 52.4 %) and average amino acid identity (AAI, 95.6%) values with B. apousia W8102T. Strain S053-2T shared 91.1 % ANI, 41.9 % dDDH and 92.5 % AAI values with B. asteroides DSM 20089T. Acid production from l-arabinose, d-xylose, d-mannose, amygdalin, cellobiose, maltose, melibiose, sucrose, raffinose, gentiobiose and l-fucose, and activity of esterase lipase (C8) and α-fucosidase could differentiate strain S053-2T from B. asteroides DSM 20089T. Acid production from d-mannose, maltose, sucrose, melezitose and gentiobiose, and activity of α-fucosidase could differentiate strain S053-2T from B. apousia W8102T. Based upon the data obtained in the present study, a novel species, Bifidobacterium mizhiense sp. nov., is proposed, and the type strain is S053-2T (=JCM 34710T=CCTCC AB 2021129T).

Apilactobacillus zhangqiuensis sp. nov. and Apilactobacillus xinyiensis sp. nov., isolated from the gut of honeybee (Apis mellifera).

Three Gram-stain-positive bacterial strains (designated F502-1T, F575-4T and F582-1) were isolated from the gut of honeybee (Apis mellifera). These strains were characterized using a polyphasic taxonomic approach. Results of 16S rRNA gene sequence analysis indicated that strain F502-1T was phylogenetically related to the type strains of Apilactobacillus kunkeei, Apilactobacillus nanyangensis and Apilactobacillus apinorum, having 98.7-99.9 % 16S rRNA gene sequence similarities, 84.6-92.5 % pheS sequence similarities and 95.2-99.0 % rpoA sequence similarities, and that strains F575-4T and F582-1 were closely related to the type strain of Apilactobacillus ozensis, having 99.7 and 99.4 % 16S rRNA gene sequence similarities, respectively. Strains F575-4T and F582-1 had less than 88.7 % pheS and 96.4 % rpoA sequence similarities to strain F502-1T and type strains of all Apilactobacillus species. The average nucleotide identity and digital DNA-DNA hybridization values between strains F502-1T, F575-4T, F582-1 and type strains of all Apilactobacillus species were less than 91.3 and 43.5 %, respectively, confirming that they represent two novel species within the genus Apilactobacillus. Based upon the data obtained in the present study, two novel species, Apilactobacillus zhangqiuensis sp. nov. and Apilactobacillus xinyiensis sp. nov., are proposed and the type strains are F502-1T (=JCM 34500T=CCTCC AB 2021026T) and F575-4T (=JCM 34501T=CCTCC AB 2021028T), respectively.

Companilactobacillus salsicarnum Zheng et al. 2020 is a later heterotypic synonym of Companilactobacillus mishanensis (Wei and Gu 2019) Zheng et al. 2020.

Lactobacillus mishanensis was isolated from Chinese traditional pickle, and validly published in October 2019. Lactobacillus salsicarnum was isolated from salami products in Germany, and effectively described in November 2019. In the reclassification of the genus Lactobacillus by Zheng et al. in April 2020, L. mishanensis was transferred to Companilactobacillus as Companilactobacillus mishanensis comb. nov., and Companilactobacillus salsicarnum was proposed as a novel species. In the present study, the relationship between C. mishanensis and C. salsicarnum was evaluated. The type strains of C. mishanensis and C. salsicarnum shared 100 % 16S rRNA gene sequence similarity, 100 % pheS sequence similarity, 99.9 % rpoA sequence similarity, a 99.9 % average nucleotide identity value and a 99.5 % digital DNA-DNA hybridization value, indicating that they represent the same species. On the basis of the results presented here, we propose C. salsicarnum [Zheng et al. 2020] as a later heterotypic synonym of C. mishanensis (Wei and Gu 2019) [Zheng et al. 2020].

Lactobacillus huangpiensis sp. nov. and Lactobacillus laiwuensis sp. nov., isolated from the gut of honeybee (Apis mellifera).

Four Gram-stain-positive bacterial strains were isolated from the gut of honeybee (Apis mellifera) in China. These strains were characterized using a polyphasic taxonomic approach. The data demonstrated that three of the four strains represented two novel species of the genus Lactobacillus, strains F306-1T and F551-2T were designated as the type strains. Results of 16S rRNA gene sequence analysis indicated that strains F306-1T, F447 and F551-2T were phylogenetically related to the type strains of Lactobacillus kimbladii and Lactobacillus kullabergensis, having 99.1-99.7 % 16S rRNA gene sequence (about 1400 bp) similarities. The phylogenetic tree based on concatenated pheS, rpoA, gyrB, hsp60, recA, rpoB and tuf sequences (4114 bp) and the phylogenomic tree based on whole genome sequences indicated that strains F306-1T and F447 were most closely related to L. kullabergensis Biut2NT, and strain F551-2T was most closely related to L. kimbladii Hma2NT. Strains F306-1T and F447 shared 99.9 % average nucleotide identity (ANI), 99.7 % digital DNA-DNA hybridization (dDDH) and 99.9 % average amino acid identity (AAI) values, indicating that they belong to the same species. Strain F306-1T exhibited the highest ANI (94.4 %), dDDH (56.7 %) and AAI (94.7 %) values to L. kullabergensis Biut2NT. Strain F551-2T had the highest ANI (94.0 %), dDDH (54.3 %) and AAI (95.8 %) values with L. kimbladii Hma2NT. Acid production from amygdalin, maltose, starch, gentiobiose and turanose, activity of esterase (C4) and α-glucosidase, growth with 3 % NaCl at 37 °C under strict anaerobic condition (on mMRS agar plates), and growth with 1-6% NaCl at 37 °C under aerobic condition (on mMRS agar plates supplemented with 0.05 % cysteine or with 1 % cysteine and 2 % fructose) could differentiate strains F306-1T and F447 from L. kullabergensis DSM 26262T. Acid production from d-glucose, arbutin and gentiobiose, growth with 3 % NaCl at 37 °C under strict anaerobic condition (on mMRS agar plates), and growth at 45 °C under strict anaerobic condition (on mMRS agar plates) could differentiate strain F551-2T from L. kimbladii DSM 26263T. Based upon the data obtained in the present study, two novel species, Lactobacillus huangpiensis sp. nov. and Lactobacillus laiwuensis sp. nov., are proposed and the type strains are F306-1T (=LMG 32144T=JCM 34361T=CCTCC AB 2020300T) and F551-2T (=JCM 34502T=CCTCC AB 2021027T), respectively.

Levilactobacillus humaensis sp. nov. and Lapidilactobacillus luobeiensis sp. nov., isolated from traditional Chinese pickle.

Two Gram-stain-positive bacterial strains, designated 213-9(3)T and 30-1(2)T, were isolated from traditional Chinese pickle, and were characterized using a polyphasic taxonomic approach. Results of 16S rRNA gene sequence analysis indicated that strain 213-9(3)T was most closely related to Levilactobacillus paucivorans TMW 1.1424T, Levilactobacillus huananensis 151-2BT and Levilactobacillus lindianensis 220-4T, having 99.7-99.9 % 16S rRNA gene sequence similarities; strain 30-1(2)T was most closely related to Lapidilactobacillus achengensis 247-4T, with 99.4 % 16S rRNA gene sequence similarity. Strain 213-9(3)T shared the highest pheS (93.9 %), rpoA (99.3 %) and concatenated pheS and rpoA (97.5 %) sequence similarities to L. paucivorans TMW 1.1424T. Strain 30-1(2)T had the highest pheS (82.4 %), rpoA (95.5 %) and concatenated pheS and rpoA (91.2 %) sequence similarities to L. achengensis 247-4T. The phylogenetic relationships based on concatenated pheS and rpoA sequences and whole genome sequences were identical to those based on 16S rRNA gene sequences. Strain 213-9(3)T exhibited the highest average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values (92.7 and 48.8 %, respectively) to L. paucivorans DSM 22467T. Strain 30-1(2)T had the highest ANI (84.4 %) and dDDH (32.8 %) values with L. achengensis 247-4T. Acid production from d-galactose, d-glucose, d-mannose, N-acetyl-ß-glucosaminidase, arbutin, salicin, cellobiose, maltose, gentiobiose, d-tagatose and gluconate, hydrolysis of aesculin, and activity of cystine arylamidase could differentiate strain 213-9(3)T from L. paucivorans DSM 22467T. Acid production from l-arabinose, d-ribose, d-xylose and d-galactose, and activity of alkaline phosphatase, esterase (C4), α-mannosidase and α-fucosidase could differentiate strain 30-1(2)T from L. achengensis 247-4T. Based upon the data obtained in the present study, two novel species, Levilactobacillus humaensis sp. nov. and Lapidilactobacillus luobeiensis sp. nov., are proposed and the type strains are 213-9(3)T (=CCM 9241T=CCTCC AB 2022115T=JCM 35554T) and 30-1(2)T (=CCM 9240T=CCTCC AB 2022114T=JCM 35553T), respectively.

Rejection of the reclassification of Leuconostoc gasicomitatum as Leuconostoc gelidum subsp. gasicomitatum based on whole genome analysis.

In 2014, Rahkila et al. transferred Leuconostoc gasicomitatum to Leuconostoc gelidum as L. gelidum subsp. gasicomitatum comb. nov. based on a 75 % DNA-DNA hybridization value. In the present study, the taxonomic status of L. gelidum subsp. gasicomitatum is re-evaluated by a polyphasic approach, including 16S rRNA, pheS, rpoA, recA, and atpA gene sequence analyses, phylogenomic treeing, analyses of ANI (average nucleotide identity) and dDDH (digital DNA-DNA hybridization), fatty acid methyl ester analysis and a phenotypic characterization. On the basis of the ANI and dDDH values, we propose to reject the proposal of Rahkila et al. to reclassify L. gasicomitatum as L. gelidum subsp. gasicomitatum.

Proposal of Lactococcus garvieae subsp. bovis Varsha and Nampoothiri 2016 as a later heterotypic synonym of Lactococcus formosensis Chen et al. 2014 and Lactococcus formosensis subsp. bovis comb. nov.

Currently, Lactococcus garvieae contains two subspecies: L. garvieae subsp. bovis and L. garvieae subsp. garvieae. In a study by Varsha and Nampoothiri, high pheS (99.7 %) and rpoA (99.6 %) sequence similarities indicated that L. garvieae subsp. bovis and Lactococcus formosensis probably have a close taxonomic relationship; low pheS (92.2 %) and rpoA (97.8 %) sequence similarities and relatively low DNA-DNA hybridization value (75.8 %) indicated that L. garvieae subsp. bovis and L. garvieae subsp. garvieae probably represent two different species. In the present study, the taxonomic relationships between L. garvieae subsp. bovis, L. garvieae subsp. garvieae and L. formosensis were re-examined based on sequence analyses of 16S rRNA, pheS, recA, rpoA and rpoB genes, average nucleotide identity (ANI), digital DNA-DNA hybridization (dDDH) values, average amino acid identity (AAI), fatty acid methyl ester analysis and phenotypic characterization. L. garvieae subsp. bovis LMG 30663T exhibited 97.3 % ANI, 78.3 % dDDH and 96.4 % AAI values to L. formosensis NBRC 109475T, higher than the threshold for species demarcation (95-96, 70 and 95-96 %, respectively), indicating that L. garvieae subsp. bovis LMG 30663T and L. formosensis NBRC 109475T belong to the same species. L. garvieae subsp. bovis LMG 30663T had 91.2 % ANI, 43.3 % dDDH and 92.9-93.0% AAI values with the type strain of L. garvieae subsp. garvieae, indicating that they represent two different species. Because L. formosensis has been proposed and validated before L. garvieae subsp. bovis, L. garvieae subsp. bovis is transferred to L. formosensis as L. formosensis subsp. bovis comb. nov. The type strain of L. formosensis subsp. bovis is BSN307T (=DSM 100577T=MCC 2824T=KCTC 21083T=LMG 30663T). The type strain of L. formosensis subsp. formosensis is 516T (=NBRC 109475T=BCRC 80576T).

The mutL Gene as a Genome-Wide Taxonomic Marker for High Resolution Discrimination of Lactiplantibacillus plantarum and Its Closely Related Taxa.

The current taxonomy of the Lactiplantibacillus plantarum group comprises of 17 closely related species that are indistinguishable from each other by using commonly used 16S rRNA gene sequencing. In this study, a whole-genome-based analysis was carried out for exploring the highly distinguished target genes whose interspecific sequence identity is significantly less than those of 16S rRNA or conventional housekeeping genes. In silico analyses of 774 core genes by the cano-wgMLST_BacCompare analytics platform indicated that csbB, morA, murI, mutL, ntpJ, rutB, trmK, ydaF, and yhhX genes were the most promising candidates. Subsequently, the mutL gene was selected, and the discrimination power was further evaluated using Sanger sequencing. Among the type strains, mutL exhibited a clearly superior sequence identity (61.6-85.6%; average: 66.6%) to the 16S rRNA gene (96.7-100%; average: 98.4%) and the conventional phylogenetic marker genes (e.g., dnaJ, dnaK, pheS, recA, and rpoA), respectively, which could be used to separat tested strains into various species clusters. Consequently, species-specific primers were developed for fast and accurate identification of L. pentosus, L. argentoratensis, L. plantarum, and L. paraplantarum. During this study, one strain (BCRC 06B0048, L. pentosus) exhibited not only relatively low mutL sequence identities (97.0%) but also a low digital DNA-DNA hybridization value (78.1%) with the type strain DSM 20314T, signifying that it exhibits potential for reclassification as a novel subspecies. Our data demonstrate that mutL can be a genome-wide target for identifying and classifying the L. plantarum group species and for differentiating novel taxa from known species.

Apilactobacillus nanyangensis sp. nov., Secundilactobacillus hailunensis sp. nov., Secundilactobacillus yichangensis sp. nov., Levilactobacillus andaensis sp. nov., Levilactobacillus wangkuiensis sp. nov., Levilactobacillus lanxiensis sp. nov., Lacticaseibacillus mingshuiensis sp. nov. and Lacticaseibacillus suilingensis sp. nov., isolated from traditional Chinese pickle and the gut of honeybee (Apis mellifera).

Thirteen Gram-stain-positive bacterial strains were isolated from Chinese traditional pickle and the gut of honeybee (Apis mellifera). These strains were characterized using a polyphasic taxonomic approach. The data demonstrated that 12 of the 13 strains represented eight novel species belonging to the genera Apilactobacillus, Secundilactobacillus, Levilactobacillus and Lacticaseibacillus; strains HN36-1T, 887-11T, F79-211-2T, 866-3T, 6-5(1)T, 13B17T, 117-1T and ZW152T were designated as the type strains. Based upon the data of polyphasic characterization obtained in the present study, eight novel species, Apilactobacillus nanyangensis sp. nov., Secundilactobacillus hailunensis sp. nov., Secundilactobacillus yichangensis sp. nov., Levilactobacillus andaensis sp. nov., Levilactobacillus wangkuiensis sp. nov., Levilactobacillus lanxiensis sp. nov., Lacticaseibacillus mingshuiensis sp. nov. and Lacticaseibacillus suilingensis sp. nov., are proposed and the type strains are HN36-1T (=JCM 33867T=CCTCC AB 2019385T), 887-11T (=NCIMB 15201T=CCM 8950T=JCM 33864T=CCTCC AB 2018396T), F79-211-2T (=NCIMB 15254T=JCM 33866T=CCTCC AB 2019384T), 866-3T (=JCM 33863T=CCTCC AB 2019383T), 6-5(1)T (=NCIMB 15229T=CCM 8977T=JCM 33564T=CCTCC AB 2019168T), 13B17T (=NCIMB 15230T=CCM 8979T=JCM 33565T=CCTCC AB 2019167T), 117-1T (=NCIMB 15232T=CCM 8980T=JCM 33567T) and ZW152T (=JCM 34363T=CCTCC AB 2020299T=LMG 32143T=CCM 9110T), respectively.

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

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).

Proposal to reclassify Lactobacillus zhaodongensis, Lactobacillus zeae, Lactobacillus argentoratensis and Lactobacillus buchneri subsp. silagei as Lacticaseibacillus zhaodongensis comb. nov., Lacticaseibacillus zeae comb. nov., Lactiplantibacillus argentoratensis comb. nov. and Lentilactobacillus buchneri subsp. silagei comb. nov., respectively and Apilactobacillus kosoi as a later heterotypic synonym of Apilactobacillus micheneri.

Recently, the members of the genus Lactobacillus have been reclassified by Zheng et al. At the same time, Lactobacillus buchneri subsp. silagei, Lactobacillus zhaodongensis, Lactobacillus argentoratensis and Lactobacillus zeae have been successively and validly published, and Lactobacillus kosoi has also been reclassified. In the present study, all these species and subspecies were re-evaluated by 16S rRNA gene sequence analysis or a combination of 16S rRNA gene sequence analysis and phylogenomic treeing. On the basis of the results presented here, we propose to reclassify Lactobacillus zhaodongensis, Lactobacillus zeae, Lactobacillus argentoratensis and Lactobacillus buchneri subsp. silagei as Lacticaseibacillus zhaodongensis comb. nov., Lacticaseibacillus zeae comb. nov., Lactiplantibacillus argentoratensis comb. nov. and Lentilactobacillus buchneri subsp. silagei comb. nov., respectively and Apilactobacillus kosoi as a later heterotypic synonym of Apilactobacillus micheneri.

Proposal of Bifidobacterium saeculare Biavati et al. 1992 as a later heterotypic synonym of Bifidobacterium gallinarum Watabe et al. 1983 and Bifidobacterium gallinarum subsp. saeculare subsp. nov.

In 2018, Nouioui et al. transferred Bifidobacterium gallinarum and Bifidobacterium saeculare to Bifidobacterium pullorum as B. pullorum subsp. gallinarum and B. pullorum subsp. saeculare on the basis of digital DNA-DNA hybridization (dDDH) values. These two new subspecies were validated in the same year. However, we found that the genome (GenBank/ENA/DDBJ accession number JGZJ01000000) of B. pullorum used by Nouioui et al. in the dDDH analysis cannot represent B. pullorum. So, the taxonomic relationship between B. gallinarum, B. saeculare and B. pullorum should be re-examined. B. pullorum DSM 20433T had 88.7-89.0 % average nucleotide identity (ANI) values and 37.5-38.0 % dDDH values to the type strains of B. gallinarum and B. saeculare, respectively, less than the threshold for species demarcation, confirming that B. pullorum represents a different species from B. gallinarum and B. saeculare. The ANI values and dDDH values between the type strains of B. gallinarum and B. saeculare were 96.7-96.9 % and 73.0-73.3 %, respectively, greater than the threshold for species demarcation, confirming that they represent the same species. Relatively low dDDH values (less than the 79-80 % threshold for subspecies demarcation) between the type strains of B. gallinarum and B. saeculare indicated that B. saeculare can be considered as a subspecies of B. gallinarum. On the basis of the results presented here, (i) B. gallinarum and B. saeculare should not be transferred to B. pullorum; (ii) we propose B. saeculare Biavati et al. 1992 as a later heterotypic synonym of B. gallinarum Watabe et al. 1983 and as a new subspecies of B. gallinarum, for which the name B. gallinarum subsp. saeculare subsp. nov. is proposed.

Proposal of Lactobacillus kosoi Chiou et al. 2018 as a later heterotypic synonym of Lactobacillus micheneri McFrederick et al. 2018, elevation of Lactobacillus plantarum subsp. argentoratensis to the species level as Lactobacillus argentoratensis sp. nov., and Lactobacillus zhaodongensis sp. nov., isolated from traditional Chinese pickle and the intestinal tract of a honey bee (Apis mellifera).

Lactobacillus kosoi Chiou et al. 2018 and Lactobacillus micheneri McFrederick et al. 2018 are closely related, and they share 100 % 16S rRNA gene sequence similarity, 99.6 % pheS gene sequence similarity, 100 % rpoA gene sequence similarity, 97.3 % average nucleotide identity (ANI) value and 76.6 % in silico DNA-DNA hybridization (isDDH) value, indicating that they represent the same species. Fatty acid methyl esters (FAME) analysis and phenotypic characterization also indicated that L. kosoi and L. micheneri are very similar. We propose L. kosoi Chiou et al. 2018 as a later heterotypic synonym of L. micheneri McFrederick et al. 2018. The taxonomic position of Lactobacillus plantarum subsp. argentoratensis in the L. plantarum group was re-examined using a polyphasic approach, including sequence analyses of 16S rRNA, pheS, rpoA and recA genes, average nucleotide identity analysis, in silico DNA-DNA hybridization, fatty acid methyl ester analysis and phenotypic characterization. Results of 16S rRNA gene sequence analysis indicated that L. plantarum subsp. argentoratensis was closely related to L. plantarum subsp. plantarum, L. pentosus and L. paraplantarum in the L. plantarum group, sharing 99.6-99.7 % 16S rRNA gene sequence similarities. Results of pheS, rpoA and recA gene sequence analyses indicated that L. plantarum subsp. argentoratensis was most closely related to L. plantarum subsp. plantarum, having 91.8 % pheS gene sequence similarity, 98.9 % rpoA gene sequence similarity and 93.1 % recA gene sequence similarity. L. plantarum subsp. argentoratensis DSM 16365T shared 95.6 % ANI value and 62.9 % isDDH value with L. plantarum subsp. plantarum ATCC 14917T. The low isDDH value confirmed that L. plantarum subsp. argentoratensis and L. plantarum subsp. plantarum represent two different species, rather than two different subspecies in the L. plantarum group. On the basis of the data from polyphasic characterization obtained in the present study and in previous studies, L. plantarum subsp. argentoratensis is elevated to the species level and represents a novel species of the genus Lactobacillus, for which the name Lactobacillus argentoratensis sp. nov. is proposed and the type strain is DKO 22T (=CIP 108320T=DSM 16365T=JCM 16169T). Two novel Gram-stain-positive bacterial strains, designated 1206-1T and F027-1-2, were isolated from traditional pickle in Heilongjiang Province, PR China, and from the intestinal tract of a honey bee (Apis mellifera) in Hubei Province, PR China, respectively. The two bacteria were characterized by a polyphasic approach, including 16S rRNA gene sequence analysis, pheS gene sequence analysis, rpoA gene sequence analysis, fatty acid methyl ester analysis, average nucleotide identity analysis, in silico DNA-DNA hybridization analysis and an analysis of phenotypic features. The results of 16S rRNA gene sequence analysis indicated that strains 1206-1T and F027-1-2 were distantly related to Lactobacillus sharpeae, Lactobacillus hulanensis, Lactobacillus songhuajiangensis, Lactobacillus pantheris, Lactobacillus thailandensis, Lactobacillus camelliae, Lactobacillus jixianensis, Lactobacillus nasuensis, Lactobacillus baoqingensis, Lactobacillus manihotivorans and Lactobacillus porcinae. Strain 1206-1T exhibited 94.2-96.4 % 16S rRNA gene sequence similarities, 69.5-83.3 % pheS gene sequence similarities and 73.1-90.3 % rpoA gene sequence similarities to type strains of phylogenetically related species. ANI and isDDH values between strain 1206-1T and the type strains of phylogenetically related species were 52.7-73.7 % and 21.1-30.1 %, respectively. On the basis of the data obtained in the present study, a novel species, Lactobacillus zhaodongensis sp. nov. is proposed and the type strain is 1206-1T (=CCM 8981T=CCTCC AB 2019200T=LMG 31620T).

Weissella sagaensis sp. nov., isolated from traditional Chinese yogurt.

Three Gram-stain-positive bacterial strains, designated X0750T, X0278 and X0401, isolated from traditional yogurt in Tibet Autonomous Region, PR China, were characterized by a polyphasic approach, including sequence analyses of the 16S rRNA gene and three housekeeping genes (pheS, rpoA and recA), determination of average nucleotide identity (ANI) and average amino acid identity (AAI), in silico DNA-DNA hybridization (isDDH), fatty acid methyl ester (FAME) analysis and phenotypic characterization. Strain X0750T was phylogenetically related to the type strains of Weissella hellenica, Weissella bombi, Weissella paramesenteroides, Weissella jogaejeotgali, Weissella thailandensis, Weissella oryzae, Weissella cibaria and Weissella confusa, having 94.4-100 % 16S rRNA gene sequence similarities, 76.7-90.0 % pheS gene sequence similarities, 88.9-99.4 % rpoA gene sequence similarities and 77.6-92.8 % recA gene sequence similarities, respectively. ANI, isDDH and AAI values between strain X0750T and type strains of phylogenetically related species were less than 90.4, 40.9 and 92.8 % respectively, confirming that strain X0750T represents a novel species within the genus Weissella. Based upon the data obtained in the present study, a novel species, Weissella sagaensis sp. nov., is proposed and the type strain is X0750T(=NCIMB 15192T=CCM 8924T=LMG 31184T=CCTCC AB 2018403T).