The first large scale rDNA amplicon database of soil microbiomes from Pamir Plateau, China.

The Eastern Pamir, distinguished with high altitude, extremely arid and cold climate, limited nutrients and sparse vegetation, is a unique ecological reservoir. Microbial communities play a central role in maintaining Eastern Pamir's ecosystem functioning. Despite the ecological significance, due to the difficulty of sample collection and microbial isolation, the microbial diversity and its functionality at the Pamir Plateau have been rarely documented. To fill this gap, 80 soil samples from 17 sites across different elevations were collected, performed the rDNA amplicon sequencing to present the first large-scale overview of bacterial, archaeal, and fungal communities in the Eastern Pamir. Microbiome analysis revealed that the bacteria Actinobacteria, Alphaproteobacteria and Bacteroidia, alongside such as archaea Nitrososphaeria and Halobacteria, and fungi including Dothideomycetes, Sordariomycetes and Eurotiomycetes were dominant lineages at class level in soil microbial communities. The community structure and biodiversity of soil microorganisms provided by this dataset would be pivotal for future studies aimed at understanding the biogeographical distribution, ecological functions and environmental responses of microbial communities of the Pamir Plateau.

Composition and distribution of bacterial communities and potential radiation-resistant bacteria at different elevations in the eastern Pamirs.

Altitude and ultraviolet (UV) radiation may affect the community composition and distribution of microorganisms in soil ecosystems. In this study, 49 soil samples from 10 locations were collected from different elevations on the eastern Pamir Plateau and analyzed for soil microbial community structure and function using high-throughput sequencing. The results showed that soil samples from different elevations of the eastern Pamir Plateau contained 6834 OTUs in 26 phyla and 399 genera. The dominant phyla common to different elevations were Actinobacteria, Proteobacteria, Bacteroidota, Acidobacteriota, and Gemmatimonadota. The dominant genera were Rubrobacter, Sphingomonas, Nocardioides, and Solirubrobacter. Species richness increased slightly with elevation, and there were significant differences in community composition between the elevations. Elevation and UV exposure are important factors that drive changes in bacterial communities. The results of the KEGG pathway showed that drug resistance, antineoplastic, aging, replication, and repair were enhanced and then slightly decreased with increasing elevation. Bacterial communities at different elevations were rich in radiation-resistant microorganisms, and the main genera were Rubrobacter, Sphingomonas, Nocardioides, Pontibacter, and Streptomyces. The findings have shown the composition and distribution of bacterial communities at different elevations on the Eastern Pamir Plateau. Potentially radiation tolerant microbial species were also examined. The results are of considerable importance for the succession of bacterial microorganisms in the plateau region, the study of radiation tolerant bacterial germplasm resources, and the application of biofunctionality.

Pontibacter kalidii sp. nov., isolated from rhizosphere soil of Kalidium foliatum.

A Gram-negative, aerobic, gliding motile, rod-shaped bacterium, designated XAAS-72T, was isolated from the rhizosphere soil of Kalidium foliatum sampled in the Xinjiang Uyghur Autonomous Region, PR China. Cells grew at 4-45 °C, pH 5.0-8.0 and 0-8% NaCl, with optimal growth at 20-30 °C, pH 6.0-7.0 and 1-2 % NaCl. Strain XAAS-72T is closely related to members of the genus Pontibacter, namely Pontibacter korlensis CCTCC AB 206081T (97.6%) and Pontibacter flavimaris ACCC 19859T (97.2 %), and <94.6 % related to other currently described Pontibacter strains. The average nucleotide identity values between XAAS-72T and P. korlensis CCTCC AB 206081T and P. flavimaris ACCC 19859T were 77.9 and 86.9 %, respectively; the corresponding digital DNA-DNA hybridization values were 21.7 and 31.8 %. Menaquinone-7 was the predominant respiratory menaquinone. The polar lipids consisted of phosphatidylethanolamine, two unidentified aminophospholipids, two unidentified glycolipids and five unidentified lipids. The major cellular fatty acids were summed feature 4 (containing iso-C17 : 1 I/anteiso-C17 : 1 B), summed feature 3 (containing C16 : 1 ω7c/C16 : 1 ω6c) and iso-C15 : 0. The genome length of strain XAAS-72T was 5 054 860 bp with a genomic DNA G+C content of 54.5 mol%. The phenotypic and genotypic data suggest that strain XAAS-72T represents a novel species of the genus Pontibacter, for which the name Pontibacter kalidii sp. nov. is proposed. The strain is XAAS-72T (CGMCC 16594T=KCTC 72095T).

Effect of Ionizing Radiation on the Bacterial and Fungal Endophytes of the Halophytic Plant Kalidium schrenkianum.

Endophytic bacteria and fungi colonize plants that grow in various types of terrestrial and aquatic ecosystems. Our study investigates the communities of endophytic bacteria and fungi of halophyte Kalidium schrenkianum growing in stressed habitats with ionizing radiation. The geochemical factors and radiation (at low, medium, high level and control) both affected the structure of endophytic communities. The bacterial class Actinobacteria and the fungal class Dothideomycetes predominated the endophytic communities of K. schrenkianum. Aerial tissues of K. schrenkianum had higher fungal diversity, while roots had higher bacterial diversity. Radiation had no significant effect on the abundance of bacterial classes. Soil pH, total nitrogen, and organic matter showed significant effects on the diversity of root endophytes. Radiation affected bacterial and fungal community structure in roots but not in aerial tissues, and had a strong effect on fungal co-occurrence networks. Overall, the genetic diversity of both endophytic bacteria and fungi was higher in radioactive environments, however negative correlations were found between endophytic bacteria and fungi in the plant. The genetic diversity of both endophytic bacteria and fungi was higher in radioactive environments. Our findings suggest that radiation affects root endophytes, and that the endophytes associated with aerial tissues and roots of K. schrenkianum follow different mechanisms for community assembly and different paradigms in stress response.

Seasonal Dynamics and Persistency of Endophyte Communities in Kalidium schrenkianum Shifts Under Radiation Stress.

Endophytes are essential components of plant microbiota. Studies have shown that environmental factors and seasonal alternation can change the microbial community composition of plants. However, most studies have mainly emphasized the transitive endophyte communities and seasonal alternation but paid less attention to their persistence through multiple seasons. Kalidium schrenkianum is a perennial halophyte growing in an arid habitat with radiation stress (137Cs) in northwest China. In this study, K. schrenkianum growing under different environmental stresses were selected to investigate the dynamics and persistency of endophytic microbial communities amid seasons in a year. The results showed that Gammaproteobacteria and unassigned Actinobacteria were the most dominant bacterial communities, while the most dominant fungal communities were Dothideomycetes, unassigned Fungi, and Sodariomycetes. The bacterial community diversity in roots was higher than that in aerial tissues, and root communities had higher diversity in summer and autumn. In contrast, the fungal community diversity was higher in aerial tissues comparing to roots, and the highest diversity was in spring. Season was a determinant factor in the microbial community composition in the roots but not in the aerial tissues. RaupCrick index suggested that the bacterial communities were mainly shaped by stochastic processes. Our research investigated the community traits and members with temporal persistency. For example, bacterial taxa Afipia, Delftia, Stenotrophomonas, Xanthomonadaceae_B_OTU_211, and fungal taxa Neocamarosporium F_OTU_388, F_OTU_404, F_OTU_445, and unassigned Fungi F_OTU_704, F_OTU_767 showed higher frequencies than predicted in all the four seasons tested with neutral community model. The networks of co-occurrence associations presented in two or more seasons were visualized which suggested potential time-continuous core modules in most communities. In addition, the community dynamics and persistency also showed different patterns by radiation levels. Our findings would enhance our understanding of the microbial community assembly under environmental stress, and be promising to improve the development of integrated concept of core microbiome in future.

Deinococcus detaillensis sp. nov., isolated from humus soil in Antarctica.

A Gram-staining-positive, non-motile, coccus or short-rod-shaped bacterium, designated H1T, was isolated from a humus soil sample in the Detaille Island of Antarctica. The 16S rRNA gene sequence result indicated that strain H1T shared the highest 16S rRNA gene sequence identity with the type strain of Deinococcus alpinitundrae (96.2%). Growth of strain H1T occurred at 4-25 °C, pH 6.0-8.0 and in the presence of 0-1.0% NaCl (w/v). The respiratory quinone was MK-8. The major fatty acids were C16:0, C17:0 cyclo and summed feature 3 (C16:1 ω7c/C16:1 ω6c). The polar lipids were aminoglycophospholipid, aminophospholipid, glycolipid and glycophospholipid. The cell wall peptidoglycan type was A3ß. The genomic DNA G + C content was 61.3 mol%. The average nucleotide identity (ANI) between strain H1T and the closely related Deinococcus members was below the cut-off level (95-96%) for species identification. Based on the above results, strain H1T represents a novel species of the genus Deinococcus, for which the name Deinococcus detaillensis sp. nov. is proposed. Type strain is H1T (= CGMCC 1.13938T = JCM 33291T).

Biotransformation of Huperzine A by Irpex lacteus-A fungal endophyte of Huperzia serrata.

The biotransformation of huperzine A (hupA), one of the characteristic bioactive constituents of the medicinal plant Huperzia serrata, by a fungal endophyte of the host plant was studied. Two previously undescribed compounds 1-2, along with a known analog 8α,15α-epoxyhuperzine A (3), were isolated and identified. The structures of all the isolates were established by spectroscopic methods including NMR, MS, IR, and UV spectra. In particular, the absolute configurations of 1 and 2 were elucidated by CD spectra comparison and theoretic NOE strength calculation. In the LPS-induced neuro-inflammation injury assay, 1-3 exhibited moderate neuroprotective activity by increasing the viability of U251 cell lines with EC50 values of 35.3 ±â€¯0.9, 32.1 ±â€¯0.9, and 50.3 ±â€¯0.8 nM, respectively.

Biotransformation of Huperzine B by a Fungal Endophyte of Huperzia serrata.

The biotransformation of huperzine B (hupB), one of the characteristic bioactive constituents of the medicinal plant Huperzia serrata, by a fungal endophyte of the host plant was studied. One new compound, 8α,15α-epoxyhuperzine B (1), along with two known oxygenated hupB analogs, 16-hydroxyhuperzine B (2) and carinatumin B (3), was isolated and identified. The structures of all the isolates were deduced by spectroscopic methods including NMR, MS, IR, and UV spectra. The known compounds 2 and 3 were obtained from a microbial source for the first time. To the best of our knowledge, it is the first report on the microbial transformation of hupB and would facilitate further structural modification of hupB by chemo-enzymatic method. In the LPS-induced neuro-inflammation injury assay, 8α,15α-epoxyhuperzine B (1) exhibited moderate neuroprotective activity by increasing the viability of U251 cell lines with an EC50 of 40.1 nm.

Deinococcus malanensis sp. nov., isolated from radiation-polluted soil.

A Gram-staining positive, non-spore forming, short rod-shaped and coccus-shaped, non-motile, pink-colored, gamma- and UV-resistant strain, designated T93T was isolated from soil of Malan area in Xinjiang Uyghur Autonomous Region, Northwest China. The taxonomic position of the new isolate was determined using a polyphasic approach. Strain T93T shared the highest 16 S rRNA gene sequence similarity with Deinococcus deserti VCD115T (97.54%). The genomic DNA G+C content of the isolate T93T was 61.7 mol%. The predominant menaquinone was MK-8, while the major cellular fatty acids were iso-C16:0, C15:1 ω6c, C16:0, C17:1 ω8c and Summed Feature 3 (comprising C16:1 ω7c and/or C16:1 ω6c). The major polar lipid profiles consisted of diphosphatidylglycerol and phosphatidylinositol mannoside. Based on the phenotypic and genotypic data, strain T93T is considered to represent a novel species of the genus Deinococcus, for which the name Deinococcus malanensis sp. nov. is proposed. The type strain is T93T (= KCTC 33563T = JCM 30331T).

Paenibacillus wulumuqiensis sp. nov. and Paenibacillus dauci sp. nov., two novel species of the genus Paenibacillus.

Two Gram-staining-positive, aerobic, motile, endospore-forming, rod-shaped bacteria, designated strains Y24(T) and H9(T) were isolated from cold spring and carrot (Daucus L.) samples, respectively, in Xinjiang Uyghur Autonomous Region, north-western China. The taxonomic positions of the two new isolates were determined by using a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences and DNA-DNA hybridizations showed that strains Y24(T) and H9(T) were two different novel species belonging to the genus Paenibacillus, with Paenibacillus hunanensis FeL05(T) as their closest relative. The genomic DNA G + C contents of the two isolates Y24(T) and H9(T) were 48.1 and 46.6 mol %, respectively. The cell wall peptidoglycan contained meso-diaminopimelic acid. The predominant menaquinone was both as MK-7. The major cellular fatty acids were anteiso-C15:0, C16:0, iso-C16:0, anteiso-C17:0 and iso-C15:0. The polar lipid profiles consisted of phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and two glycolipids as the major components. On the basis of their phenotypic characteristics, the two isolates represent two different novel species of the genus Paenibacillus, for which the names Paenibacillus wulumuqiensis sp. nov. (type strain Y24(T) = CPCC 100602(T) = JCM 30284(T)) and Paenibacillus dauci sp. nov. (type strain H9(T) = CPCC 100608(T) = JCM 30283(T)) are proposed.

Yuhushiella deserti gen. nov., sp. nov., a new member of the suborder Pseudonocardineae.

A thermotolerant, Gram-stain-positive, aerobic, sporangium-forming actinomycete, strain RA45(T), was isolated from a desert region in Xinjiang Uigur Autonomous Region, north-western China. Comparative analysis of the 16S rRNA gene sequence and phenotypic characterization revealed that strain RA45(T) belonged phylogenetically to the family Pseudonocardiaceae of the suborder Pseudonocardineae. Strain RA45(T) showed more than 5  % 16S rRNA gene sequence divergence from recognized species of genera in the family Pseudonocardiaceae, forming a distinct lineage within the evolutionary radiation occupied by the genera Amycolatopsis, Prauserella, Thermocrispum, Saccharomonospora, Saccharopolyspora and Sciscionella, but distinct from each of them. The affiliation to the family was supported by the presence of suborder- and family-specific 16S rRNA signature nucleotides, a DNA G+C content of 69.9 mol%, the presence of meso-diaminopimelic acid, ribose, arabinose, glucose and galactose, which are characteristic components of cell-wall chemotype IV of actinomycetes, the presence of menaquinone MK-9(H4) as the major respiratory lipoquinone, a lack of mycolic acids and the presence of an N-acetylated type of muramic acid. However, strain RA45(T) differed from known genera of the family in its polar lipid composition: the major phospholipids were phosphatidylethanolamine, phosphatidylinositol mannosides, phosphatidylmethylethanolamine, diphosphatidylglycerol, phospholipids of unknown structure and phospholipids of unknown structure containing glucosamine (phospholipid type IV). Based on its morphological, chemotaxonomic and phylogenetic characteristics, strain RA45(T) is considered to represent a novel species of a new genus in the family Pseudonocardiaceae, for which the name Yuhushiella deserti gen. nov., sp. nov. is proposed. The type strain of Yuhushiella deserti is RA45(T) (=CGMCC 4.5579(T) =JCM 16584(T)).

Paenibacillus algorifonticola sp. nov., isolated from a cold spring.

A Gram-stain-positive, endospore-forming, rod-shaped bacterium, designated XJ259(T), was isolated from a cold spring sample from Xinjiang Uyghur Autonomous Region, China. The isolate grew optimally at 20-30 °C and pH 7.3-7.8. Comparative analysis of the 16S rRNA gene sequence showed that isolate XJ259(T) belonged phylogenetically to the genus Paenibacillus, and was most closely related to Paenibacillus xinjiangensis B538(T) (with 96.6 % sequence similarity), Paenibacillus glycanilyticus DS-1(T) (96.3 %) and Paenibacillus castaneae Ch-32(T) (96.1 %), sharing less than 96.0 % sequence similarity with all other members of the genus Paenibacillus. Chemotaxonomic analysis revealing menaquinone-7 (MK-7) as the major isoprenoid quinone, diphosphatidylglycerol, phosphatidylethanolamine and two unknown phosphoglycolipids as the major cellular polar lipids, a DNA G+C content of 47.0 mol%, and anteiso-C15:0 and C16:0 as the major fatty acids supported affiliation of the new isolate to the genus Paenibacillus. Based on these data, isolate XJ259(T) is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus algorifonticola sp. nov. is proposed. The type strain is XJ259(T) ( = CGMCC 1.10223(T)  = JCM 16598(T)).