Archaeal diversity in acid mine drainage from Dabaoshan Mine, China

Three acid mine drainage (AMD) samples collected from Dabaoshan Mine (Guangdong Province, China) were studied. In addition to physicochemical analyses, the diversity and community structures of the archaeal communities in these samples were described at the genetic level by amplified ribosomal DNA restriction analysis (ARDRA). Nine different ARDRA patterns were obtained from 146 clones and were studied as operational taxonomic units (OTUs), which were re-amplified and sequenced. Sequence data and phylogenetic analysis showed that most of the clones belonged to the Thermoplasmatales, and that archaea belonging to the Sulfolobales were absent. Only 1 OTU attributed to Ferroplasma was found and was observed to be abundant in all 3 samples. Eight OTUs were related to 2 new undefined groups in the Thermoplasmatales. Of the 8 OTUs, the clones in 2 similar units were isolated from samples collected from an abandoned sulfide mine (Huelva, Spain) and those in 5 similar units were isolated from samples collected from a closed copper mine (Tonglushan, China). These diversities were characterized by the reciprocal of Simpson's index (1/D) and correlated with the concentrations of ferrous ions and toxic ions in the AMD samples. The high temperature of the sampling sites was one of the factors that could explain why archaea belonging to the Thermoplasmatales were abundant in the analyzed AMD samples while those belonging to the Sulfolobales were absent.     

Novel prokaryotic diversity in sediments of Tunisian multipond solar saltern

The phylogenetic diversity of a sediment microbial community from two ponds having different salinities, 150–200 g/l (M2) and 250–300 g/l (TS38), of an Sfax (Tunisia) solar saltern, was investigated using 16S rRNA clone libraries. The 16S rRNA genes from 135 bacterial clones and 105 archaeal clones were sequenced and phylogenetically analyzed. 32 operational taxonomic units (OTUs) were generated for Bacteria and 64 for Archaea. The bacterial community in M2 sediment was affiliated only with Bacteroidetes, while that in TS38 sediment was dominated by clones affiliated with Bacteroidetes, (gamma, alpha, delta) Proteobacteria and unclassified bacteria; these represented 56.52, 26.08, 4.34, 4.34 and 8.7% of the OTUs, respectively. In the M2 and TS38 sediments, 44.44 and 43.47% of the bacterial OTUs, respectively, were novel. All archaeal sequences fell into the Euryarchaeota phylum. In both sediments, 38.46 and 72.55% of the OTUs had less than 97% 16S rRNA sequence identity, representing novel OTUs. Two sequences, retrieved from TS38 sediment, were found to be affiliated with the candidate division MSBL-1 defining two OTUs. The sediment phylogenetic study revealed the presence of a highly diverse microbial population in highly salty media.     

Microbial diversity at the moderate acidic stage in three different sulfidic mine tailings dumps generating acid mine drainage

In freshly deposited sulfidic mine tailings the pH is alkaline or circumneutral. Due to pyrite or pyrrhotite oxidation the pH is dropping over time to pH values <3 at which acidophilic iron- and sulfur-oxidizing prokaryotes prevail and accelerate the oxidation processes, well described for several mine waste sites. The microbial communities at the moderate acidic stage in mine tailings are only scarcely studied. Here we investigated the microbial diversity via 16S rRNA gene sequence analysis in eight samples (pH range 3.2–6.5) from three different sulfidic mine tailings dumps in Botswana, Germany and Sweden. In total 701 partial 16S rRNA gene sequences revealed a divergent microbial community between the three sites and at different tailings depths. Proteobacteria and Firmicutes were overall the most abundant phyla in the clone libraries. Acidobacteria, Actinobacteria, Bacteroidetes, and Nitrospira occurred less frequently. The found microbial communities were completely different to microbial communities in tailings at <pH 3 described in the literature.     

Characterization of specificity of bacterial community structure within the burrow environment of the marine polychaete Hediste (Nereis) diversicolor

Bioturbation is known to stimulate microbial communities, especially in macrofaunal burrows where the abundance and activities of bacteria are increased. Until now, these microbial communities have been poorly characterized and an important ecological question remains: do burrow walls harbor similar or specific communities compared with anoxic and surface sediments? The bacterial community structure of coastal sediments inhabited by the polychaete worm Hediste diversicolor was investigated. Surface, burrow wall and anoxic sediments were collected at the Carteau beach (Gulf of Fos, Mediterranean Sea). Bacterial diversity was determined by analyzing small subunit ribosomal RNA (16S rRNA) sequences from three clone libraries (168, 179 and 129 sequences for the surface, burrow wall and anoxic sediments, respectively). Libraries revealed 306 different operational taxonomic units (OTUs) belonging to at least 15 bacterial phyla. Bioinformatic analyses and comparisons between the three clone libraries showed that the burrow walls harbored a specific bacterial community structure which differed from the surface and anoxic environments. More similarities were nevertheless found with the surface assemblage. Inside the burrow walls, the bacterial community was characterized by high biodiversity, which probably results from the biogeochemical heterogeneity of the burrow system.     

High Archaea diversity in Varvara hot spring, Bulgaria

The phylogeny of the latest recognized domain, Archaea, is still complicated and it is largely based on environmental sequences. A culture independent molecular phylogenetic analysis revealed high Archaea diversity in a terrestrial hot spring, village Varvara, Bulgaria. A total of 35 archaeal operational taxonomic units (OTUs) belonging to three of the classified five Archaea phyla were identified. Most of the sequences were affiliated with the phylum Crenarchaeota (23), grouped in four branches. The rest of the sequences showed highest similarity to the unidentified archaeal clones (9), Euryarchaeota (2), and "Korarchaeota " (1). Eight (23%) of the sequenced 16S rDNAs didn't have known close relatives and represented new and diverse OTUs, four of them forming a new archaeal subgroup without close described sequences or culturable relatives. A sequence affiliated with "Korarchaeota " showed low similarity (90%) to the closest neighbor and both sequences formed unique branch in this phylum. Consequently, the constructed archaeal libraries are characterized by (1) high proportion of OTUs representing uncultivated archaeal phylogroups, (2) the abundance of novel phylotype sequences, (3) the presence of high proportions of Crenarchaeota phylotypes unrelated to cultivated organisms and (4) the presence of a sequence only distantly related to "Korarchaeota " phylum.     

Temporal bacterial diversity and detection of putative methanotrophs in surface mats of Lonar crater lake

The phylogenetic diversity of bacterial communities in microbial mats of two different seasons from saline and hyperalkaline Lonar Lake was investigated using 16S rRNA gene library analysis. Arthrospira (Cyanobacteria) related clones (>80% of total clones) dominated libraries of both the seasons. Clear differences were found in both the seasons as the operational taxonomic units (OTUs) related to Fusibacter (LAI‐1 and LAI‐59) and Tindallia magadiensis (LAI‐27) found in post‐monsoon were not found in the pre‐monsoon library. Likewise, OTUs related to Planococcus rifietensis (LAII‐67), Bordetella hinzii (LAII‐2) and Methylobacterium variabile (LAII‐25) found in the pre‐monsoon were not found in post‐monsoon. The study was extended to identify methanotrophs in the surface mats. Libraries constructed with type I and type II methanotroph specific 16S rRNA gene primers showed the presence of clones (LAMI‐99 and LAMII‐2) closely related to Methylomicrobium buryaticum and Beijerinckiaceae family members. Denaturing gradient gel electrophoresis (DGGE) fingerprinting based on protein‐coding genes (pmoA and mxaF) further confirmed the detection of Methylomicrobium sp. Hence, we report here for the first time the detection of putative methanotrophs in surface mats of Lonar Lake. The finding of clones related to organisms with interesting functional attributes such as assimilation of C₁ compounds (LAII‐25, LAMI‐39, LAMI‐99 and LAMII‐2), non‐sulfur photosynthetic bacteria (LAMII‐43) and clones distantly affiliated to organisms of heavily polluted environments (LAI‐59 and LAMII‐52), is of significant note. These preliminary results would direct future studies on the functional dynamics of microbial mat associated food web chain in the extreme environment. (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Activity and bacterial diversity of snow around Russian Antarctic stations

The diversity and temporal dynamics of bacterial communities in pristine snow around two Russian Antarctic stations was investigated. Taxonomic analysis of rDNA libraries revealed that snow communities were dominated by bacteria from a small number of operational taxonomic units (OTUs) that underwent dramatic swings in abundance between the 54th (2008–2009) and 55th (2009–2010) Russian Antarctic expeditions. Moreover, analysis of the 55th expedition samples indicated that there was very little, if any, correspondence in abundance of clones belonging to the same OTU present in rDNA and rRNA libraries. The latter result suggests that most rDNA clones originate from bacteria that are not alive and/or active and may have been deposited on the snow surface from the atmosphere. In contrast, clones most abundant in rRNA libraries (mostly belonging to Variovorax, Janthinobacterium, Pseudomonas, and Sphingomonas genera) may be considered as endogenous Antarctic snow inhabitants.     

Structural differentiation of bacterial communities in indole-degrading bioreactors under denitrifying and sulfate-reducing conditions

The acclimated, anaerobic microbial community is an efficient method for indole-containing wastewater treatment. However, our understanding of the diversity of indole-degrading communities is still limited. We investigated two anaerobic, indole-decomposing microbial communities under both denitrifying and sulfate-reducing conditions. Utilizing a near full-length 16S rRNA gene clone library, the most dominant bacteria in the denitrifying bioreactor identified was β-proteobacteria. Among these, bacteria from genera Alicycliphilus, Acaligenes and Thauera were abundant and thought responsible for indole degradation. However, in the sulfate-reducing bioreactor, Clostridia and Actinobacteria were the dominant bacterial class found and likely the main degrading species. Microbial communities in these bioreactors shared only two operational taxonomic units (OTUs). Differences in the electron acceptors of denitrification or sulfate reduction may be responsible for the higher indole removal capacity in the denitrifying bioreactor (80%) than the capacity in the sulfate-reducing bioreactor (52%). This study is the first detailed analysis of an anaerobic indole-degrading community.     

First insights to the microbial communities in the plant process water of the multi-metal Kevitsa mine

Metallurgical processes demand large quantities of water. However, in many locations, water is becoming scarce and process water recycling is needed. Closing water loops can be challenging due to build-up of flotation chemicals, metal ions and microorganisms in the recycled water affecting the flotation performance. Here, we have characterized the microbial communities over a 2-month period in different locations of the multi-metal Kevitsa mine in Northern Finland, by microbiome sequencing, enumeration of bacteria, archaea and fungi by qPCR, and cultivation. The microbial communities showed high diversity, but were dominated by Alpha- and Gammaproteobacteria. In addition, various fungal taxa were detected, whereas the archaeal taxa were only sparsely detected from the sequence data. The number of bacterial 16S rRNA gene copies in Process water and Ni thickener overflow varied between 0.5–3.3 × 10⁵ mL⁻¹, whereas the Flotation tailings showed two orders of magnitude lower amounts. Fungi were present at 3.0 × 10²–8.1 × 10⁴ 5.8S rRNA gene copies mL⁻¹ in all samples, while the number of archaea fluctuated between 8.8 × 10¹–3.2 × 10⁵ 16S rRNA gene copies mL⁻¹. The number of all microbial groups were generally lower in September than in August. When tested on 8 different cultivation media, the microorganisms generally responded positively to organic carbon, and were also shown to oxidize thiosulfate, which may indicate that build-up of organic flotation chemicals and sulfur species from the ore may cause the microbial numbers to increase. This study is part of the H2020 ITERAMS project (Grant agreement# 730480), which strives to improve the recycling of water and minimize the environmental impact of mines.     

Detection of methanogenic Archaea in peat: comparison of PCR primers targeting the mcrA gene

Methanogens (domain Archaea) have a unique role in the carbon cycle as producers of the greenhouse gas methane (CH(4)). Methyl-coenzyme M reductase (MCR) is a vital enzyme in CH(4) production, and the mcrA gene coding for a subunit of MCR has been employed as a specific marker for the detection and differentiation of methanogen communities. A critical step in assessing environmental mcrA diversity is the selection of PCR primers. The objective of this study was to compare the diversity coverage of three published mcrA primer sets MCR, ME and ML (also known as MCR and Luton-mcrA) and their ability to discern methanogen communities in a drained peatland. The primers were applied to DNA extracts from unfertilised and ash-fertilised peat from two different depths. Amplified mcrA communities were cloned and sequenced, and the sequences were divided into operational taxonomic units (OTUs) by restriction fragment length polymorphism (RFLP) and sequence analysis. All primers recovered characteristic OTUs associated with the peat depths and treatments and confirmed a previous observation of low methanogen diversity. The minor differences in OTU ranges of the primers did not greatly affect the observed community composition. However, as the proportions of several OTUs varied strongly, the primers provided different quantitative representations of mcrA communities. We concluded that the ML and MCR primers had better amplification ranges than the ME set, but the use of MCR with peat samples was problematic due to poor amplification. Consequently, the ML primers were best suited for mcrA analysis of peatland methanogen communities.     

怀有先天性心脏病胎儿的孕妇与正常孕妇肠道菌群的高通量测序分析

目的:分析怀有先天性心脏病胎儿的孕妇(PW组)与正常孕妇(NW组)的肠道菌群特征。方法:对可能引起个体肠道菌群差异的因素加以控制,2013年6月18号~2013年12月17号收集15例正常孕妇和17例异常孕妇的粪便样本,提取细菌基因组DNA,用PCR方法扩增16S r DNA,进行二代Illumina测序。测序数据应用运算分类单位(operational taxonomic unit,OTU)聚类分析、多样性分析和分类学分析等生物信息技术分析2类孕妇肠道菌群的结构、多样性和丰度。结果:2类孕妇肠道菌群的高通量测序分析分别得到2 696 276(NW组)条和2 445 530(PW组)条优化序列,测序覆盖深度97%。经过97%相似度归并后分别得到77 243个(NW组)和75 600个OTUs(PW组);菌群多样性分析显示正常孕妇肠道菌群的Chao 1指数和Shannon指数均高于异常孕妇。在最佳分类水平上,正常孕妇肠道菌群由38个科的细菌构成,归属于14个门,以厚壁菌门(Firmicutes)为主,其次为变形菌门(Proteobacteria)、放线菌门(Actinobacteria)等。怀有先心胎儿孕妇肠道菌群构成与正常孕妇相似,最佳分类水平上由33个科的细菌构成,归属于9个门,其中Firmicutes为(75.7±15.8)%,Proteobacteria为(21.1±17.0)%,Actinobacteria为(2.0±2.1)%。在最佳分类水平上,方差分析显示两者的双歧杆菌科(Bifidobacteriaceae)和红蝽杆菌科(Coriobacteriaceae)菌种丰度有明显差异。结论:PW组孕妇与NW组孕妇相比,整体肠道菌群含量明显下降,提示PW组孕妇有更恶劣的肠道环境,其中部分菌群含量存在明显差异。先天性心脏病胎儿的发生可能与孕妇恶劣的肠道微环境有关,其中Bifidobacteriaceae和Coriobacteriaceae在先天性心脏病的预防方面可能有重要作用。     

Microbial diversity analysis of former salterns in southern Taiwan by 16S rRNA-based methods

The microbiota diversity of the former salterns in southern Taiwan was investigated by denaturing gradient gel electrophoresis (DGGE) and fluorescence in situ hybridization (FISH). Soil samples from three salterns were analyzed using DGGE and 16S rRNA from 502 colonies representing 5 archaea and 18 bacteria taxonomic groups. Each representative taxonomic group was further identified, whereas 8.7% of clones were unclassified microorganisms. Chromohalobacter, Halomonas and Virgibacillus are dominant in the Biemen saltern, Chiguensis saltern and Szutsau saltern, respectively. During FISH analysis, several taxonomic-specific probes were used. The DAPI-stained-cell count in the Szutsao saltern had a higher number of microorganisms (4.58 x 10(7) cell/cm(3)) than the other salterns. Archaea occupied 2.7-6.6% whereas bacteria accounted for 37.2-52.9% of total microbial population at the three sites. Among these three sampling sites, the Szutsao saltern had the highest diversity in halophilic microbial composition, as indicated by DGGE and FISH.     

Phylogenetic diversity of bacterial communities in South China Sea mesoscale cyclonic eddy perturbations

Eddy pumping drives a set of biogeochemical processes by lifting deep waters into the euphotic zone. To address the potential effect of such physical processes upon the bacterial community, phylogenetic diversity was determined in two cold-core cyclonic eddies in the South China Sea. 16S rDNA terminal restriction fragment length polymorphism analysis of the microbial communities through the whole water column showed a wider depth range for the intermediate transition water mass at sites inside the eddies than for those outside. This water mass contained a relatively more complex community than the euphotic and deep-water zones. Stratification of prokaryotic populations between the surface and chlorophyll maximum layer of eddy-related sites versus homogeneity of communities in the euphotic zone of the reference site, revealed by statistical analysis of 16S rDNA libraries, is most likely a reflection of isopycnal displacement induced by differing water movement inside and outside eddies. Phylogenetic analysis revealed that eddy center sites were characterized by deep-water group Alteromonadales-affiliated clones, the psychrophilic genus Octadecabacter cluster and the nitrogen-fixing phototrophic Rhodospirillaceae cluster, while Paracoccus, an important functional group, abundantly existed at the reference site outside eddies. Our analysis revealed that bacterial community structure was significantly influenced by cyclonic eddy perturbations.     

Stratification of microbial communities throughout a biological sulphate reducing up-flow anaerobic packed bed reactor,revealed through 16S metagenomics

Biological sulphate reduction (BSR) is a promising low-cost treatment of acid rock drainage effluents. In this paper, the system performance and microbial ecology of a lactate supplemented BSR up-flow anaerobic packed bed reactor (UAPBR) are evaluated across reactor height and compared to a continuous stirred tank reactor (CSTR). The biomass concentrations of planktonic and biofilm communities were quantified and subsequently characterised by 16S rRNA gene amplicon sequencing. The defined microbial communities were shown to correlate with differing availability of lactate, volatile fatty acids produced from lactate degradation and sulphate concentration. The UAPBR was able to achieve near complete sulphate conversion at a 4-day hydraulic residence time (HRT) at a sulphate feed concentration of 10.41 mM (1 g/L). The high volumetric sulphate reduction rate of 0.184 mM/L.h achieved in the first third of the reactor was attributed to OTUs present in the planktonic and biofilm communities. While the scavenging of sulphate within the final third of the UAPBR was attributed to an acetate oxidising genus of SRB which was not detected in the lactate-fed CSTR. The detailed analyses of the microbial communities throughout the UAPBR and CSTR contribute to the growing understanding of the impact of the microbial communities of BSR reactors on system performance.     

Investigation on health effects of an abandoned metal mine

To investigate potential health risks associated with exposure to metals from an abandoned metal mine, the authors studied people living near an abandoned mine (n=102) and control groups (n=149). Levels of cadmium, copper, arsenic, lead, and zinc were measured in the air, soil, drinking water, and agricultural products. To assess individual exposure, biomarkers of each metal in blood and urine were measured. beta2-microglobulin, alpha1-microglobulin, and N-acetyl-beta-glucosaminidase and bone mineral density were measured. Surface soil in the study area showed 2-10 times higher levels of metals compared to that of the control area. Metal concentrations in the groundwater and air did not show any notable differences between groups. Mean concentrations of cadmium and copper in rice and barley from the study area were significantly higher than those of the control area (p<0.05). Geometric means of blood and urine cadmium in the study area were 2.9 microg/L and 1.5 microg/g Cr, respectively, significantly higher than those in the control area (p<0.05). There were no differences in the levels of urinary markers of early kidney dysfunction and bone mineral density. The authors conclude that the residents near the abandoned mine were exposed to higher levels of metals through various routes.     

Gelatin filter capture-based high-throughput sequencing analysis of microbial diversity in haze particulate matter

Airborne particulate matter (PM), especially PM_2.5, can be easily adsorbed by human respiratory system. Their roles in carrying pathogens for spreading epidemic diseases has attracted great concern. Herein, we developed a novel gelatin filter-based and culture-independent method for investigation of the microbial diversity in PM samples during a haze episode in Tianjin, China. This method involves particle capture by gelatin filters, filter dissolution for DNA extraction, and high-throughput sequencing for analysis of the microbial diversity. A total of 584 operational taxonomic units (OTUs) of bacteria and 370 OTUs of fungi at the genus level were identified during hazy days. The results showed that both bacterial and fungal diversities could be evaluated by this method. This study provides a convenient strategy for investigation of microbial biodiversity in haze, facilitating accurate evaluation of airborne epidemic diseases.     

Colorimetric microbial diversity analysis and halotolerance along a soil salinity gradient at the Great Salt Plains of Oklahoma

Microbial diversity was measured along a salinity gradient at the Great Salt Plains of Oklahoma using colony color quantified as RGB components of microbial isolate streaks. Numerical taxonomy was performed using a UPGMA method to create trees of relatedness, define OTUs, and calculate diversity indices. Surface soil samples along a 6-m salinity gradient (from hypersaline soil with 7.5% salinity to oligohaline rangeland soil) at WP68 were dilution-plated on SP medium of various salinities and hundreds of random colonies were collected. The salinity tolerance of isolates along the gradient was determined. From the 1364 colonies examined, 338 OTUs were defined by colony color and their distribution statistically analyzed by soil type and the salinity of enrichment media. Most colonies were shades of cream that became distinguishable based on RGB color components. Diversity indices were high overall and it is likely that the OTUs defined by colony color are below the species level, at the strain level, where the greatest diversity lies in this environment. These results are complementary to previous molecular genetic analyses of 16S rRNA clone libraries from soils at the Great Salt Plains. Great diversity at lower taxonomic levels supports the suggestion that gene flow is not highly fragmented, a result of less specialization, as expected given the highly variable salinity observed at the salt flats with rain events.     

Molecular investigation of bacterial communities on intravascular catheters: no longer just Staphylococcus

Intravascular catheter-related bloodstream infections (IVC-BSIs) are associated with significant morbidity and mortality. Culture-independent molecular approaches can reveal and capture the composition of complex microbial communities, and are now being used to reveal “new” pathogens as well as the polymicrobial nature of some infections. Patients with concurrently sited arterial and central venous catheters who had clinically suspected IVC-BSIs, were examined by the high-throughput sequencing of microbial 16S rRNA. An average of 100 operational taxonomic units (OTUs, phylotypes) was observed on each IVC, indicating that IVCs were colonised by complex and diverse bacterial communities. Ralstonia (53 % of 16S rRNA sequences), Escherichia group (16 %), Propionibacterium (5 %), Staphylococcus (5 %), and Streptococcus (2 %) were the most abundant genera. There was no statistically significant difference in the bacterial communities examined from arterial and central venous catheters; from those with and without systemic antibiotic treatment; or from conventionally colonised and uncolonised IVCs. The genome of the predominant bacteria, R. pickettii AU12-08, was found to encode resistance to antimicrobial drugs of different classes. In addition, many encoded gene products are involved in quorum sensing and biofilm formation that would further contribute to increased antimicrobial drug resistance. Our results highlight the complex diversity of microbial ecosystems on vascular devices. High-throughput sequencing of 16S rRNA offers an insight into the pathogenesis of IVC-related infections, and opens up the scope for improving diagnosis and patient management.     

Novel application of the MSSCP method in biodiversity studies

Analysis of 16S rRNA sequence diversity is widely performed for characterizing the biodiversity of microbial samples. The number of determined sequences has a considerable impact on complete results. Although the cost of mass sequencing is decreasing, it is often still too high for individual projects. We applied the multi-temperature single-strand conformational polymorphism (MSSCP) method to decrease the number of analysed sequences. This was a novel application of this method. As a control, the same sample was analysed using random sequencing. In this paper, we adapted the MSSCP technique for screening of unique sequences of the 16S rRNA gene library and bacterial strains isolated from biofilms growing on the walls of an ancient gold mine in Poland and determined whether the results obtained by both methods differed and whether random sequencing could be replaced by MSSCP. Although it was biased towards the detection of rare sequences in the samples, the qualitative results of MSSCP were not different than those of random sequencing. Unambiguous discrimination of unique clones and strains creates an opportunity to effectively estimate the biodiversity of natural communities, especially in populations which are numerous but species poor.     

Study on the correlation between soil microbial diversity and ambient environmental factors influencing the safflower distribution in Xinjiang

The effects of soil microbial properties and physiographical factors on safflower distributions in the main safflower plantations of Xinjiang province in China were studied. This study may help determine the basis of the environmental factors for evaluating the geoherbalism of this medicinal plant. The soil microbial biodiversity in the bulk soil and rhizosphere of safflower at different growth stages and from different sampling plots were characterized by analyzing the environmental DNAs in the samples. With general primers targeting the 16S ribosomal DNA for bacteria and the internal transcribed spacer 1 gene for fungi, the study was performed using marker gene amplification coupled with Illumina HiSeq high-throughput sequencing technologies. Correlation analysis and a distance-based redundancy analysis were performed to determine the dominant factors affecting the distribution of the microorganism in safflower soils. A total of 16517 bacterial operational taxonomic units (OTUs) were obtained from all the 108 soil samples of nine safflower sampling plots. At the phylum level, 48 phyla have been identified with Actinobacteria (32.9%) and proteobacteria (28.7%) being predominant. For fungi, 8746 OTUs were obtained, which belonged to seven phyla with Ascomycota overwhelmingly superior in relative abundance. A significant positive correlation was found between soil microbe quantity and ASL (above sea level). Safflower was sensitive to changes in elevation, growing more abundantly in the mountainous regions at heights of around 1,200 m above sea level. It is concluded that the dominant factors affecting the distribution of microorganisms in safflower soils were soil moisture, available N, and ASL.