A Gram-staining-negative, rod-shaped, non-spore-forming bacterium, designated strain RG4-7T, was isolated from the moss Polytrichastrum formosum collected from Gawalong glacier in Tibet, China, and characterized by using a polyphasic taxonomic approach. The predominant fatty acids of strain RG4-7T were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), iso-C15 : 0 and iso-C17 : 0 3-OH. The major polar lipids were phosphatidylethanolamine, one unidentified aminophospholipid, one unidentified phospholipid, two unidentified aminolipids and one unidentified lipid. Strain RG4-7T contained MK-7 as the dominant menaquinone and the G+C content of its genomic DNA was 39.1 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain RG4-7T was affiliated to species of the genus Mucilaginibacter , and its closest relative was Mucilaginibacter jinjuensis YC7004T (97.0 % sequence similarity). However, the DNA–DNA relatedness between this strain and strain RG4-7T was only 49.1±3.7 %. Based on phylogenetic inference and phenotypic data, strain RG4-7T is considered to represent a novel species of the genus Mucilaginibacter , for which the name Mucilaginibacter polytrichastri sp. nov. is proposed. The type strain is RG4-7T ( = CGMCC 1.12493T = DSM 26907T). An emended description of the genus Mucilaginibacter is also proposed.

BackgroundPrevious studies on the bacteria associated with the bryophytes showed that there were abundant bacteria inhabited in/on these hosts. However, the type of bacteria and whether these discriminate between different bryophytes based on a particular factor remains largely unknown.ResultsThis study was designed to analyze the biodiversity and community of the bacteria associated with ten liverworts and ten mosses using Illumina-sequencing techniques based on bacterial 16S rRNA gene. A total of 125,762 high quality sequences and 437 OTUs were obtained from twenty bryophytes. Generally, there were no obvious differences between the richness of bacteria associated with liverworts and mosses; however, the diversity was significantly higher in liverworts than in mosses. The taxonomic analyses showed that there were abundant bacteria inhabited with each bryophyte and those primarily detected in all samples were within the phyla Proteobacteria, Actinobacteria, Acidobacteria, Bacteroidetes, Armatimonadetes and Planctomycetes. In addition, bacteria assigned to Chloroflexi, Fibrobacteres, Gemmatimonadetes, Chlamydiae, group of TM6 and WCHB1-60 also appeared in part of the bryophytes. The assigned bacteria included those adapted to aquatic, anaerobic and even extreme drought environments, which is consistent with the bryophyte transition from aquatic to terrestrial conditions. Of them, approximately 10 recognized genera were shared by all the samples in a higher proportion, such as Burkholderia, Novosphingobium, Mucilaginibacter, Sorangium, Frankia, Frondihatitans, Haliangium, Rhizobacter, Granulicella and Hafnia, and 11 unclassified genera were also detected in all samples, which exhibited that large amounts of unclassified bacteria could interact with the bryophytes. The Heatmap and Principle Coordinate Analyses showed that bacteria associated with six mosses displayed a higher community similarity. Notably, the bacteria associated with another four mosses exhibited higher similarity with the ten liverworts.ConclusionsThe result of further analysis of the bacterial community in different bryophytes revealed that the phylogeny of hosts might portray a strong influence on the associated bacterial community and that niche also played important roles when the hosts were phylogenetically more similar. Further studies are needed to confirm the role of phylogeny on bacterial communities and determine the level of influence on predicting which bacteria is associated with the host.

In order to better understand the factors that influence bacterial diversity and community composition in moss-associated bacteria, a study of bacterial communities in four moss species collected in three seasons was carried out via high-throughput sequencing of 16S rDNA and 16S rRNA. Moss species included Cratoneuron filicinum, Pylaisiella polyantha, Campyliadelphus polygamum, and Grimmia pilifera, with samples collected in May, July, and October 2015 from rocks at Beijing Songshan National Nature Reserve. In total, the bacterial richness and diversity were high regardless of moss species, sampling season, or data source (DNA vs. RNA). Bacterial sequences were assigned to a total of 558 OTUs and 279 genera in 16 phyla. Proteobacteria and Actinobacteria were the two most abundant phyla, and Cellvibrio, Lapillicoccus, Jatrophihabitans, Friedmanniella, Oligoflexus, and Bosea the most common genera in the samples. A clustering algorithm and principal coordinate analysis revealed that C. filicinum and C. polygamum had similar bacterial communities, as did P. polyantha and G. pilifera. Metabolically active bacteria showed the same pattern in addition to seasonal variation: bacterial communities were most similar in summer and autumn, looking at each moss species separately. In contrast, DNA profiles lacked obvious seasonal dynamics. A partial least squares discriminant analysis identified three groups of samples that correlated with differences in moss species resources. Although bacterial community composition did vary with the sampling season and data source, these were not the most important factors influencing bacterial communities. Previous reports exhibited that mosses have been widely used in biomonitoring of air pollution by enriching some substances or elements in the moss-tag technique and the abundant moss associated bacteria might also be important components involved in the related biological processes. Thus, this survey not only enhanced our understanding of the factors which influence microbial communities in mosses but also would be helpful for better use and development of the moss-tag technique in the environmental biomonitoring.

A Gram-staining-negative, rod-shaped and non-spore-forming bacterium, designated strain RG1-1T, was isolated from Takakia lepidozioides collected from Gawalong glacier in Tibet, China, and characterized by using a polyphasic taxonomic approach. The predominant fatty acids of strain RG1-1T were iso-C15 : 0 (19.8 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c, 17.0 %), C16 : 0 (9.9 %) and iso-C17 : 0 3-OH (9.4 %); its major polar lipids were phosphatidylethanolamine, four unidentified aminolipids, one unidentified phospholipid, one unidentified aminoglycolipid, one unidentified glycolipid, and three unidentified lipids. Strain RG1-1T contained MK-7 as the dominant menaquinone, and the G+C content of its genomic DNA was 49.1 mol%. Strain RG1-1T exhibited the highest 16S rRNA gene sequence similarity (91.8 %) with Flavisolibacter ginsengiterrae Gsoil 492T and Flavisolibacter ginsengisoli Gsoil 643T. Phylogenetic analysis showed that strain RG1-1T was a member of the family Chitinophagaceae , phylum Bacteroidetes . On the basis of 16S rRNA gene sequence analysis, and phenotypic and chemotaxonomic data, strain RG1-1T is considered to represent a novel species of a novel genus, for which the name Cnuella takakiae gen. nov., sp. nov. is proposed. The type strain is RG1-1T ( = CGMCC 1.12492T = DSM 26897T).

A Gram-stain negative, rod-shaped and non-endospore forming bacterium, designated strain YG4-6(T), was isolated from Polytrichastrum formosum collected from Gawalong glacier in Tibet, China and characterized by using a polyphasic taxonomic approach. The predominant fatty acids of strain YG4-6(T) were identified as iso-C15:0 (29.3 %), summed feature 3 (C16:1 ω7c and/or C16:1 ω6c as defined by MIDI, 23.5 %) and iso-C17:0 3-OH (16.5 %). The major polar lipids were found to consist of five unidentified aminolipids and three unidentified lipids. Strain YG4-6(T) was found to contain MK-6 as the dominant menaquinone and the G+C content of its genomic DNA was determined to be 37.3 mol%. The phylogenetic analysis based on 16S rRNA gene sequences showed that strain YG4-6(T) is affiliated to Chryseobacterium species, and its closest related species were Chryseobacterium aahli T68(T) (97.9 % sequence similarity), Chryseobacterium zeae JM-1085(T) (97.8 % sequence similarity), Chryseobacterium yeoncheonense DCY67(T) (97.6 % sequence similarity) and Chryseobacterium soldanellicola NBRC 100864(T) (97.2 % sequence similarity). However, the DNA-DNA relatedness values between these strains and strain YG4-6(T) were found to be clearly below 70 %. Based on the phylogenetic inference and phenotypic data, strain YG4-6(T) is considered to represent a novel species of the genus Chryseobacterium, for which the name Chryseobacterium polytrichastri sp. nov. is proposed. The type strain is YG4-6(T) (=CGMCC 1.12491(T) = DSM 26899(T)). An emended description of the genus Chryseobacterium is also proposed.