scholarly journals The Distribution and Turnover of Bacterial Communities in the Root Zone of Seven Stipa Species Across an Arid and Semi-arid Steppe

2021 ◽  
Vol 12 ◽  
Author(s):  
Xiaodan Ma ◽  
Lumeng Chao ◽  
Jingpeng Li ◽  
Zhiying Ding ◽  
Siyu Wang ◽  
...  

The bacterial communities of the root-zone soil are capable of regulating vital biogeochemical cycles and the succession of plant growth. Stipa as grassland constructive species is restricted by the difference features of east–west humidity and north–south heat, which shows the population substituting distribution. The distribution, turnover, and potential driving factors and ecological significance of the root-zone bacterial community along broad spatial gradients of Stipa taxa transition remain unclear. This paper investigated seven Stipa species root-zone soils based on high-throughput sequencing combined with the measurements of multiple environmental parameters in arid and semi-arid steppe. The communities of soil bacteria in root zone had considerable turnover, and some regular variations in structure along the Stipa taxa transition are largely determined by climatic factors, vegetation coverage, and pH at a regional scale. Bacterial communities had a clear Stipa population specificity, but they were more strongly affected by the main annual precipitation, which resulted in a biogeographical distribution pattern along precipitation gradient, among which Actinobacteria, Acidobacteria, Proteobacteria, and Chloroflexi were the phyla that were most abundant. During the transformation of Stipa taxa from east to west, the trend of diversity shown by bacterial community in the root zone decreased first, and then increased sharply at S. breviflora, which was followed by continuous decreasing toward northwest afterwards. However, the richness and evenness showed an opposite trend, and α diversity had close association with altitude and pH. There would be specific and different bacterial taxa interactions in different Stipa species, in which S. krylovii had the simplest and most stable interaction network with the strongest resistance to the environment and S. breviflora had most complex and erratic. Moreover, the bacterial community was mainly affected by dispersal limitation at a certain period. These results are conducive to the prediction of sustainable ecosystem services and protection of microbial resources in a semi-arid grassland ecosystem.

2018 ◽  
Vol 84 (9) ◽  
Author(s):  
Bing Li ◽  
Wei-Min Wu ◽  
David B. Watson ◽  
Erick Cardenas ◽  
Yuanqing Chao ◽  
...  

ABSTRACTA site in Oak Ridge, TN, USA, has sediments that contain >3% iron oxides and is contaminated with uranium (U). The U(VI) was bioreduced to U(IV) and immobilizedin situthrough intermittent injections of ethanol. It then was allowed to reoxidize via the invasion of low-pH (3.6 to 4.0), high-nitrate (up to 200 mM) groundwater back into the reduced zone for 1,383 days. To examine the biogeochemical response, high-throughput sequencing and network analysis were applied to characterize bacterial population shifts, as well as cooccurrence and coexclusion patterns among microbial communities. A pairedttest indicated no significant changes of α-diversity for the bioactive wells. However, both nonmetric multidimensional scaling and analysis of similarity confirmed a significant distinction in the overall composition of the bacterial communities between the bioreduced and the reoxidized sediments. The top 20 major genera accounted for >70% of the cumulative contribution to the dissimilarity in the bacterial communities before and after the groundwater invasion.Castellaniellahad the largest dissimilarity contribution (17.7%). For the bioactive wells, the abundance of the U(VI)-reducing generaGeothrix,Desulfovibrio,Ferribacterium, andGeobacterdecreased significantly, whereas the denitrifyingAcidovoraxabundance increased significantly after groundwater invasion. Additionally, seven genera, i.e.,Castellaniella,Ignavibacterium,Simplicispira,Rhizomicrobium,AcidobacteriaGp1,AcidobacteriaGp14, andAcidobacteriaGp23, were significant indicators of bioactive wells in the reoxidation stage. Canonical correspondence analysis indicated that nitrate, manganese, and pH affected mostly the U(VI)-reducing genera and indicator genera. Cooccurrence patterns among microbial taxa suggested the presence of taxa sharing similar ecological niches or mutualism/commensalism/synergism interactions.IMPORTANCEHigh-throughput sequencing technology in combination with a network analysis approach were used to investigate the stabilization of uranium and the corresponding dynamics of bacterial communities under field conditions with regard to the heterogeneity and complexity of the subsurface over the long term. The study also examined diversity and microbial community composition shift, the common genera, and indicator genera before and after long-term contaminated-groundwater invasion and the relationship between the target functional community structure and environmental factors. Additionally, deciphering cooccurrence and coexclusion patterns among microbial taxa and environmental parameters could help predict potential biotic interactions (cooperation/competition), shared physiologies, or habitat affinities, thus, improving our understanding of ecological niches occupied by certain specific species. These findings offer new insights into compositions of and associations among bacterial communities and serve as a foundation for future bioreduction implementation and monitoring efforts applied to uranium-contaminated sites.


2014 ◽  
Author(s):  
Alese Colehour ◽  
James F Meadow ◽  
Tara J Cepon-Robins ◽  
Theresa E Gildner ◽  
Melissa A Liebert ◽  
...  

Cassava beer, or chicha, is typically consumed daily by the indigenous Shuar people of the Ecuadorian Amazon. This traditional beverage made from cassava tuber (Manihot esculenta) improves nutritional quality and flavor while extending shelf life in a tropical climate. Bacteria responsible for chicha fermentation could be a source of microbes beneficial to human health, but little is known regarding the microbiology of chicha. We investigated bacterial community composition of chicha batches using Illumina high-throughput sequencing. Fermented chicha samples were collected from seven Shuar households in two neighboring villages in the Morona-Santiago region of Ecuador, and the composition of the bacterial communities within each chicha sample was determined by sequencing a region of the 16S ribosomal gene. Members of the genus Lactobacillus dominated all samples, demonstrating that chicha is a source of organisms related to known probiotics. Significantly greater taxonomic similarity was observed between communities in chicha samples taken within a village than those from different villages. Community composition varied among chicha samples, even those separated by short geographic distances, suggesting that ecological and/or evolutionary processes, including human preference, may be responsible for creating locally adapted and regionally resilient ferments. Our results suggest that traditional fermentation may be a form of domestication that provides endemic beneficial inocula for consumers.


2021 ◽  
Vol 12 ◽  
Author(s):  
Wen Tian ◽  
Xing Xiang ◽  
Hongmei Wang

The level of water table and temperature are two environmental variables shaping soil bacterial communities, particularly in peatland ecosystems. However, discerning the specific impact of these two factors on bacterial communities in natural ecosystems is challenging. To address this issue, we collected pore water samples across different months (August and November in 2017 and May 2018) with a gradient of water table changes and temperatures at the Dajiuhu peatland, Central China. The samples were analyzed with 16S rRNA high-throughput sequencing and Biolog EcoMicroplates. Bacterial communities varied in the relative abundances of dominant taxa and harbored exclusive indicator operational taxonomic units across the different months. Despite these differences, bacterial communities showed high similarities in carbon utilization, with preferences for esters (pyruvic acid methyl ester, Tween 40, Tween 80, and D-galactonic acid γ-lactone), amino acids (L-arginine and L-threonine), and amines (phenylethylamine and putrescine). However, rates of carbon utilization (as indicated by average well-color development) and metabolic diversity (McIntosh and Shannon index) in May and August were higher than those in November. Redundancy analysis revealed that the seasonal variations in bacterial communities were significantly impacted by the level of the water table, whereas the temperature had a fundamental role in bacterial carbon utilization rate. Co-occurrence analysis identified Sphingomonas, Mucilaginibacter, Novosphingobium, Lacunisphaera, Herminiimonas, and Bradyrhizobium as keystone species, which may involve in the utilization of organic compounds such as amino acids, phenols, and others. Our findings suggest that bacterial community functions were more stable than their compositions in the context of water table changes. These findings significantly expand our current understanding of the variations of bacterial community structures and metabolic functions in peatland ecosystems in the context of global warming and fluctuation of the water table.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9612
Author(s):  
Tong Jia ◽  
Tingyan Guo ◽  
Baofeng Chai

This study analyzed Imperata cylindrica litter to determine variation in bacterial community composition and function along with enzyme activity as phytoremediation progresses. We found significant differences in physical and chemical properties of soil and litter in the different sub-dams investigated. The Actinobacteria, Gammaproteobacteria and Alphaproteobacteria were the dominant bacteria found in the litter of the different sub-dams. The alpha diversity (α-diversity) of litter bacterial community increased over as phytoremediation progressed, while total soil carbon and total litter carbon content were positively correlated to bacterial α-diversity. Total litter carbon and total nitrogen were the key factors that influenced bacterial community structure. Heavy metal can influence the degradation of litters by altering the composition of the microbial community. Furthermore, bacterial communities encoded with alpha-amylase (α-amylase) dominated during the initial phytoremediation stage; however, bacterial communities encoded with hemicellulase and peroxidase gradually dominated as phytoremediation progressed. Findings from this study provide a basis for exploring litter decomposition mechanisms in degraded ecosystems, which is critically important to understand the circulation of substances in copper tailings dams.


2014 ◽  
Author(s):  
Alese Colehour ◽  
James F Meadow ◽  
Tara J Cepon-Robins ◽  
Theresa E Gildner ◽  
Melissa A Liebert ◽  
...  

Cassava beer, or chicha, is typically consumed daily by the indigenous Shuar people of the Ecuadorian Amazon. This traditional beverage made from cassava tuber (Manihot esculenta) improves nutritional quality and flavor while extending shelf life in a tropical climate. Bacteria responsible for chicha fermentation could be a source of microbes beneficial to human health, but little is known regarding the microbiology of chicha. We investigated bacterial community composition of chicha batches using Illumina high-throughput sequencing. Fermented chicha samples were collected from seven Shuar households in two neighboring villages in the Morona-Santiago region of Ecuador, and the composition of the bacterial communities within each chicha sample was determined by sequencing a region of the 16S ribosomal gene. Members of the genus Lactobacillus dominated all samples, demonstrating that chicha is a source of organisms related to known probiotics. Significantly greater taxonomic similarity was observed between communities in chicha samples taken within a village than those from different villages. Community composition varied among chicha samples, even those separated by short geographic distances, suggesting that ecological and/or evolutionary processes, including human preference, may be responsible for creating locally adapted and regionally resilient ferments. Our results suggest that traditional fermentation may be a form of domestication that provides endemic beneficial inocula for consumers.


2020 ◽  
Author(s):  
Zongfu Hu ◽  
Deying Ma ◽  
huaxin Niu ◽  
Jie Chang ◽  
Jianhua Yu ◽  
...  

Abstract This study aimed to evaluate the effects of enzymes (cellulase combined with galactosidase),, and the combination of these enzymes with Lactobacillus plantarum (LP) on bacterial diversity using high-throughput sequencing. Alfalfa forages were treated without or with cellulase + ɑ-galactosidase (CEGA), cellulase + LP (CELP), ɑ-galactosidase + LP (GALP). After 56 days of ensiling, All the treated silages exhibited improved fermentation quality as reflecting by decreased pH, ammonium-N and increased lactic acid levels compared to the control silage. Enzymatic treatment improved nutrients value by increased the level of crude protein and decreased the neutral detergent fibre (NDF) level. Treatment of the silage significantly changed the bacterial community, as determined by the PCoA test. LAB dominated the bacterial community of the treated silage after ensiling. The dominant bacteria from Garciella, Enterococcus, Lactobacillus and Pediococcus in control silage changed to Lactobacillus and Pediococcus in CEGA silage, and Lactobacillus in CELP and GALP silages. Collectively, enzymes and enzyme in combination with inoculants both greatly increased the abundance of LAB, with Enterococcus, Lactobacillus and Pediococcus in enzymes only silge (CEGA) and Lactobacillus in enzyme combination with inoculants silage (CELP and GALP).


2019 ◽  
Vol 69 (13) ◽  
pp. 1461-1473 ◽  
Author(s):  
Cheng-yu Wang ◽  
Xue Zhou ◽  
Dan Guo ◽  
Jiang-hua Zhao ◽  
Li Yan ◽  
...  

Abstract Purpose To understand which environmental factors influence the distribution and ecological functions of bacteria in agricultural soil. Method A broad range of farmland soils was sampled from 206 locations in Jilin province, China. We used 16S rRNA gene-based Illumina HiSeq sequencing to estimated soil bacterial community structure and functions. Result The dominant taxa in terms of abundance were found to be, Actinobacteria, Acidobacteria, Gemmatimonadetes, Chloroflexi, and Proteobacteria. Bacterial communities were dominantly affected by soil pH, whereas soil organic carbon did not have a significant influence on bacterial communities. Soil pH was significantly positively correlated with bacterial operational taxonomic unit abundance and soil bacterial α-diversity (P<0.05) spatially rather than with soil nutrients. Bacterial functions were estimated using FAPROTAX, and the relative abundance of anaerobic and aerobic chemoheterotrophs, and nitrifying bacteria was 27.66%, 26.14%, and 6.87%, respectively, of the total bacterial community. Generally, the results indicate that soil pH is more important than nutrients in shaping bacterial communities in agricultural soils, including their ecological functions and biogeographic distribution.


Author(s):  
Yi-Feng Li ◽  
Xing-Pan Guo ◽  
Yu-Ru Chen ◽  
De-Wen Ding ◽  
Jin-Long Yang

Mussels are typical macrofouling organisms in the world. In this study, the interaction between the settlement ofMytilus coruscusplantigrades and bacterial community on coloured substrata was determined. Bacterial communities in biofilms developed on seven coloured substrata were analysed by Illumina Miseq sequencing. The mussel settlement response to coloured substrata with no biofilms was also examined.Flavobacteria, AlphaproteobacteriaandGammaproteobacteriawere the first, second and third most dominant groups in seven biofilm samples. The results suggest that the inducing activities of these biofilms on plantigrade settlement varied with coloured substrata and the lowest percentage of settlement was observed on biofilms on the green substratum. High-throughput sequencing showed that bacterial community in biofilms also changed with the substratum colour. No significant difference in the inducing activity on plantigrade settlement was observed between the coloured substrata with no biofilms. Thus, difference in plantigrade settlement response may be correlated to the changes in bacterial community on coloured substrata. This finding extends current knowledge of interaction among mussel settlement and bacterial community variability.


Holzforschung ◽  
2018 ◽  
Vol 72 (7) ◽  
pp. 609-619 ◽  
Author(s):  
Qiuxia Li ◽  
Lixiang Cao ◽  
Wenfeng Wang ◽  
Hongming Tan ◽  
Tao Jin ◽  
...  

AbstractThe microbial impact on waterlogged wooden cultural relics fromXiaobaijiao No. 1shipwreck was investigated by means of a high-throughput sequencing technology, while the focus was on the composition of prokaryotic microorganisms in 10 wood samples collected from different parts of the shipwreck. A total of 28 501 different operational taxonomic units (OTUs) were obtained based on 97% sequence similarity. The α-diversity index is for the bacterial diversity, which was the highest and the lowest in the samples SS8 and SS5, respectively. Proteobacteria was the largest category of bacterial abundance (47.3%) followed by Bacteroidetes (10%). α-Proteobacteria was the first largest bacteria class with the maximum abundance (21.0%) followed by γ-Proteobacteria (16.9%). Other groups rich in the following species were found: Bacteroidales (13.3%), Thiotrichales (5.0%), Rhodobacterales (4.2%), Rhizobiales (4.0%), Chromatiales (3.5%), Oceanospirillales (3.3%), Flavobacteriales (2.9%) and Sphingomonadales (2.8%). At the level of the bacterial genus,Marinomonaswas the most abundant one. Phylogenetic analysis revealed that there are some differences in the composition of bacterial communities from different wood samples. The species number of bacteria in the relics of this shipwreck was far more than that reported in those found in Europe, and in which species composition was similar to the benthic bacteria in the corresponding sea area. The coexistence of anaerobic and aerobic bacteria is remarkable.


PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12105
Author(s):  
Fangnan Xiao ◽  
Yuanyuan Li ◽  
Guifang Li ◽  
Yaling He ◽  
Xinhua Lv ◽  
...  

Tamarix is a dominant species in the Tarim River Basin, the longest inland river in China. Tamarix plays an important role in the ecological restoration of this region. In this study, to investigate the soil bacterial community diversity in Tamarix shrubs, we collected soil samples from the inside and edge of the canopy and the edge of nebkhas and non-nebkhas Tamarix shrubs located near the Yingsu section in the lower reaches of Tarim River. High throughput sequencing technology was employed to discern the composition and function of soil bacterial communities in nebkhas and non-nebkhas Tamarix shrubs. Besides, the physicochemical properties of soil and the spatial distribution characteristics of soil bacteria and their correlation were analyzed. The outcomes of this analysis demonstrated that different parts of Tamarix shrubs had significantly different effects on soil pH, total K (TK), available K (AK), ammonium N (NH4+), and available P (AP) values (P < 0.05), but not on soil moisture (SWC), total salt (TDS), electrical conductivity (EC), organic matter (OM), total N (TN), total P (TP), and nitrate N (NO3−) values. The soil bacterial communities identified in Tamarix shrubs were categorized into two kingdoms, 71 phyla, 161 classes, 345 orders, 473 families, and 702 genera. Halobacterota, unidentified bacteria, and Proteobacteria were found to be dominant phyla. The correlation between the soil physicochemical factors and soil bacterial community was analyzed, and as per the outcomes OM, AK, AP, EC, and NH4+ were found to primarily affect the structure of the soil bacterial community. SWC, TK and pH were positively correlated with each other, but negatively correlated with other soil factors. At the phyla level, a significantly positive correlation was observed between the Halobacterota and AP, OM as well as Bacteroidota and AK (P < 0.01), but a significantly negative correlation was observed between the Chloroflexi and AK, EC (P < 0.01). The PICRUSt software was employed to predict the functional genes. A total of 6,195 KEGG ortholog genes were obtained. The function of soil bacteria was annotated, and six metabolic pathways in level 1, 41 metabolic pathways in level 2, and 307 metabolic pathways in level 3 were enriched, among which the functional gene related to metabolism, genetic information processing, and environmental information processing was found to have the dominant advantage. The results showed that the nebkhas and canopy of Tamarix shrubs had a certain enrichment effect on soil nutrients content, and bacterial abundance and significant effects on the structure and function of the soil bacterial community.


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