Oenococcus oeni is a lactic acid bacteria species encountered particularly in wine, where it achieves the malolactic fermentation. Molecular typing methods have previously revealed that the species is made of several genetic groups of strains, some being specific to certain types of wines, ciders or regions. Here, we describe 36 recently released O. oeni genomes and the phylogenomic analysis of these 36 plus 14 previously reported genomes. We also report three genome sequences of the sister species Oenococcus kitaharae that were used for phylogenomic reconstructions. Phylogenomic and population structure analyses performed revealed that the 50 O. oeni genomes delineate two major groups of 12 and 37 strains, respectively, named A and B, plus a putative group C, consisting of a single strain. A study on the orthologs and single nucleotide polymorphism contents of the genetic groups revealed that the domestication of some strains to products such as cider, wine, or champagne, is reflected at the genetic level. While group A strains proved to be predominant in wine and to form subgroups adapted to specific types of wine such as champagne, group B strains were found in wine and cider. The strain from putative group C was isolated from cider and genetically closer to group B strains. The results suggest that ancestral O. oeni strains were adapted to low-ethanol containing environments such as overripe fruits, and that they were domesticated to cider and wine, with group A strains being naturally selected in a process of further domestication to specific wines such as champagne.

BackgroundFructobacillus spp. in fructose-rich niches belong to the family Leuconostocaceae. They were originally classified as Leuconostoc spp., but were later grouped into a novel genus, Fructobacillus, based on their phylogenetic position, morphology and specific biochemical characteristics. The unique characters, so called fructophilic characteristics, had not been reported in the group of lactic acid bacteria, suggesting unique evolution at the genome level. Here we studied four draft genome sequences of Fructobacillus spp. and compared their metabolic properties against those of Leuconostoc spp.ResultsFructobacillus species possess significantly less protein coding sequences in their small genomes. The number of genes was significantly smaller in carbohydrate transport and metabolism. Several other metabolic pathways, including TCA cycle, ubiquinone and other terpenoid-quinone biosynthesis and phosphotransferase systems, were characterized as discriminative pathways between the two genera. The adhE gene for bifunctional acetaldehyde/alcohol dehydrogenase, and genes for subunits of the pyruvate dehydrogenase complex were absent in Fructobacillus spp. The two genera also show different levels of GC contents, which are mainly due to the different GC contents at the third codon position.ConclusionThe present genome characteristics in Fructobacillus spp. suggest reductive evolution that took place to adapt to specific niches.Electronic supplementary materialThe online version of this article (doi:10.1186/s12864-015-2339-x) contains supplementary material, which is available to authorized users.

Root-associated microbial communities are very important in the adaptation of halophytes to coastal environments. However, little has been reported on microbial community structures related to halophytes, or on comparisons of their compositions among halophytic plant species. Here, we studied the diversity and community structure of both rhizosphere and root endosphere bacteria in two halophytic plants: Glaux maritima and Salicornia europaea. We sampled the rhizosphere, the root endosphere, and bulk control soil samples, and performed bacterial 16S rRNA sequencing using the Illumina MiSeq platform to characterize the bacterial community diversities in the rhizosphere and root endosphere of both halophytes. Among the G. maritima samples, the richness and diversity of bacteria in the rhizosphere were higher than those in the root endosphere but were lower than those of the bulk soil. In contrast for S. europaea, the bulk soil, the rhizosphere, and the root endosphere all had similar bacterial richness and diversity. The number of unique operational taxonomic units within the root endosphere, the rhizosphere, and the bulk soil were 181, 366, and 924 in G. maritima and 126, 416, and 596 in S. europaea, respectively, implying habitat-specific patterns for each halophyte. In total, 35 phyla and 566 genera were identified. The dominant phyla across all samples were Proteobacteria and Bacteroidetes. Actinobacteria was extremely abundant in the root endosphere from G. maritima. Beneficial bacterial genera were enriched in the root endosphere and rhizosphere in both halophytes. Rhizobium, Actinoplanes, and Marinomonas were highly abundant in G. maritima, whereas Sulfurimonas and Coleofasciculus were highly abundant in S. europaea. A principal coordinate analysis demonstrated significant differences in the microbiota composition associated with the plant species and type of sample. These results strongly indicate that there are clear differences in bacterial community structure and diversity between G. maritima and S. europaea. This is the first report to characterize the root microbiome of G. maritima, and to compare the diversity and community structure of rhizosphere and root endosphere bacteria between G. maritima and S. europaea.

An aerobic, Gram-negative bacterium, strain KMM 329 T , was isolated from a deep-sea sponge specimen from the Philippine Sea and subjected to a polyphasic taxonomic investigation. Comparative 16S rRNA gene sequence analysis showed that strain KMM 329 T clustered with the species of the genus Lysobacter. The highest level of 16S rRNA gene sequence similarity (97.0 %) was found with respect to Lysobacter concretionis KCTC 12205 T ; lower values (96.4-95.2 %) were obtained with respect to the other recognized Lysobacter species. The value for DNA-DNA relatedness between strain KMM 329 T and L. concretionis KCTC 12205 T was 47 %. Branched fatty acids 16 : 0 iso, 15 : 0 iso, 11 : 0 iso 3-OH and 17 : 1 iso were found to be predominant. Strain KMM 329 T had a DNA G+C content of 69.0 mol%. On the basis of the phenotypic, chemotaxonomic, DNA-DNA hybridization and phylogenetic data, strain KMM 329 T represents a novel species of the genus Lysobacter, for which the name Lysobacter spongiicola sp. nov. is proposed. The type strain is KMM 329 T (5NRIC 0728 T 5JCM 14760 T ).

The contents, components, and synthesis genes of cell wall teichoic acid (WTA) in 18 strains of Lactobacillus plantarum were compared. The WTA of each strain was classified by its components as being either the glycerol- or the ribitol-type. The different strains in the WTA type showed marked differences also in two gene regions, tagD1-tagF2 and lp_1816-tagB2, as for the presence or absence, nucleotide sequences, and transcriptional activities. Our results clearly showed that the tagD1-tagF2 and lp_1816-tagB2 regions contained the synthesis genes of the WTA backbone of L. plantarum. We verified that the genes in the tagD1-tagF2 region were involved in the synthesis of the glycerol-type backbone. Furthermore, we propose that the genes in the lp_1816-tagB2 region were tarI, tarJ, tarK, and tarL, which are involved in the synthesis of the ribitol-type backbone.

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A group of five Gram-negative, aerobic, halotolerant, non-pigmented bacteria isolated from shallow sediment samples and invertebrate specimens collected from the Gulf of Alaska and the Sea of Japan was subjected to taxonomic study. On the basis of 16S rRNA gene sequence analysis, the novel isolates were affiliated to the genus Cobetia , sharing the highest sequence similarity of 99.3–99.9 % with Cobetia marina DSM 4741T. DNA–DNA hybridization experiments between and among the novel strains and C. marina DSM 4741T and Cobetia crustatorum JCM 15644T revealed that the five strains represent three separate genospecies, which could be differentiated in their morphological, physiological and biochemical characteristics. Halomonas halodurans NBRC 15607T was included in this study as it has recently been reported to exhibit high 16S rRNA gene sequence similarity to C. marina DSM 4741T, and it showed a high DNA relatedness value of 96 % with C. marina DSM 4741T, indicating that they belong to the same species. On the basis of phylogenetic analysis, DNA–DNA hybridization and phenotypic characterization, three novel species are proposed, named Cobetia amphilecti sp. nov. (type strain KMM 1561T  = NRIC 0815T  = CCUG 49560T), Cobetia litoralis sp. nov. (type strain KMM 3880T  = NRIC 0814T  = CCUG 49563T) and Cobetia pacifica sp. nov. (type strain KMM 3879T  = NRIC 0813T  = CCUG 49562T). It is also proposed that Halomonas halodurans is a later heterotypic synonym of Cobetia marina , and emended descriptions of the genus Cobetia and the species Cobetia marina are provided.

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