scholarly journals Identifying the Biogeographic Patterns of Rare and Abundant Bacterial Communities Using Different Primer Sets on the Loess Plateau

2021 ◽  
Vol 9 (1) ◽  
pp. 139
Author(s):  
Quanchao Zeng ◽  
Shaoshan An
Keyword(s):  
Community Structure ◽  
Environmental Factors ◽  
Bacterial Community ◽  
Bacterial Diversity ◽  
Bacterial Communities ◽  
Land Uses ◽  
The Loess Plateau ◽  
Soil Bacterial Diversity ◽  
Soil Bacterial ◽  
Rare Bacteria

High-throughput sequencing is commonly used to study soil microbial communities. However, different primers targeting different 16S rRNA hypervariable regions often generate different microbial communities and result in different values of diversity and community structure. This study determined the consequences of using two bacterial primers (338f/806r, targeting the V3-V4 region, and 520f/802r, targeting the V4 region) to assess bacterial communities in the soils of different land uses along a latitudinal gradient. The results showed that the variations in the soil bacterial diversity in different land uses were more evident based on the former pair. The statistical results showed that land use had no significant impact on soil bacterial diversity when primer pair 520f/802r was used. In contrast, when primer pair 338f/806r was used, the cropland and orchard soils had significantly higher operational taxonomic units (OTUs) and Shannon diversity index values than those of the shrubland and grassland soils. Similarly, the soil bacterial diversity generated by primer pair 338f/806r was significantly impacted by mean annual precipitation, soil total phosphorus (TP), soil total nitrogen (TN), and soil available phosphorus (AVP), while the soil bacterial diversity generated by primer pair 520f/802r showed no significant correlations with most of these environmental factors. Multiple regression models indicated that soil pH and soil organic carbon (SOC) shaped the soil bacterial community structure on the Loess Plateau regardless of what primer pair was used. Climatic conditions mainly affected the diversity of rare bacteria. Abundant bacteria are more sensitive than rare bacteria to environmental changes. Very little of the variation in the rare bacterial community was explained by environmental factors or geographic distance, suggesting that the communities of rare bacteria are unpredictable. The distributions of the abundant taxa were mainly determined by variations in environmental factors.

scholarly journals Regulating soil bacterial diversity, community structure and enzyme activity using residues from golden apple snails

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiaxin Wang ◽  
Xuening Lu ◽  
Jiaen Zhang ◽  
Guangchang Wei ◽  
Yue Xiong
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Diversity ◽  
Soil Nutrients ◽  
Pomacea Canaliculata ◽  
Soil Bacterial Diversity ◽  
Amended Soils ◽  
Soil Bacterial ◽  
The Impact ◽  
Amended Soil

Abstract It has been shown that the golden apple snail (GAS, Pomacea canaliculata), which is a serious agricultural pest in Southeast Asia, can provide a soil amendment for the reversal of soil acidification and degradation. However, the impact of GAS residue (i.e., crushed, whole GAS) on soil bacterial diversity and community structure remains largely unknown. Here, a greenhouse pot experiment was conducted and 16S rRNA gene sequencing was used to measure bacterial abundance and community structure in soils amended with GAS residue and lime. The results suggest that adding GAS residue resulted in a significant variation in soil pH and nutrients (all P < 0.05), and resulted in a slightly alkaline (pH = 7.28–7.75) and nutrient-enriched soil, with amendment of 2.5–100 g kg−1 GAS residue. Soil nutrients (i.e., NO3-N and TN) and TOC contents were increased (by 132–912%), and some soil exocellular enzyme activities were enhanced (by 2–98%) in GAS residue amended soil, with amendment of 1.0–100 g kg−1 GAS residue. Bacterial OTU richness was 19% greater at the 2.5 g kg−1 GAS residue treatment than the control, while it was 40% and 53% lower at 100 g kg−1 of GAS residue and 50 g kg−1 of lime amended soils, respectively. Firmicutes (15–35%) was the most abundant phylum while Bacterioidetes (1–6%) was the lowest abundant one in GAS residue amended soils. RDA results suggest that the contents of soil nutrients (i.e., NO3-N and TN) and soil TOC explained much more of the variations of bacterial community than pH in GAS residue amended soil. Overuse of GAS residue would induce an anaerobic soil environment and reduce bacterial OTU richness. Soil nutrients and TOC rather than pH might be the main factors that are responsible for the changes of bacterial OTU richness and bacterial community structure in GAS residue amended soil.

scholarly journals Drivers of Soil Bacterial Diversity in Sandy Grasslands in China

2021 ◽  
Author(s):  
Chengchen Pan ◽  
Qi Feng ◽  
Yulin Li ◽  
Xiaoya Yu ◽  
Shilong Ren
Keyword(s):  
Community Structure ◽  
Environmental Factors ◽  
Bacterial Community ◽  
Bacterial Diversity ◽  
Bacterial Community Structure ◽  
Rrna Gene ◽  
Sandy Land ◽  
Α Diversity ◽  
Soil Bacterial ◽  
Sandy Grasslands

Abstract Bacteria constitute great abundances and groups on Earth and control many important processes in terrestrial ecosystems. However, our understanding of the interactions between soil bacteria and environmental factors remains limited, especially in sensitive and fragile ecosystems. In this study, geographic patterns of bacterial diversity across the four sandy grasslands along a 1600 km north-south transect in northern China were characterized by high-throughput 16S rRNA gene sequencing. Then, we analyzed the driving factors behind the patterns in bacterial diversity. The results showed that of the 21 phyla detected, the most abundant were Proteobacteria, Actinobacteria, Acidobacteria and Firmicutes (average relative abundance > 5%). Soil bacterial α diversity, calculated as the bacterial phylotype richness and Faith’s phylogenetic diversity, was highest in the Otingdag Sandy Land and lowest in the Mu Us Sandy Land. Soil EC was the most influential factor driving bacterial α diversity. The bacterial communities differed significantly among the four sandy grasslands, and the bacterial community structure was significantly affected by environmental factors and geographic distance. Of the environmental variables examined, climatic factors (MAT and MAP) and edaphic properties (pH and EC) explained the highest proportion of the variation in bacterial community structure. Biotic factors such as plant species richness and aboveground biomass exhibited weak but significant associations with bacterial α diversity. Our findings revealed the important role of climate and salinity factors in controlling bacterial diversity; understanding these roles is critical for predicting the impacts of climate change and promoting sustainable management strategies for ecosystem services in these sandy lands.

scholarly journals Soil Bacterial Community Response and Nitrogen Cycling Variations Associated with Subalpine Meadow Degradation on the Loess Plateau, China

2020 ◽  
Vol 86 (9) ◽  
Author(s):  
Zhengming Luo ◽  
Jinxian Liu ◽  
Tong Jia ◽  
Baofeng Chai ◽  
Tiehang Wu
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Loess Plateau ◽  
Bacterial Communities ◽  
N Cycling ◽  
The Loess Plateau ◽  
Soil Bacterial Communities ◽  
Subalpine Meadow ◽  
Soil Bacterial ◽  
Meadow Degradation

ABSTRACT Grassland degradation is an ecological problem worldwide. This study aimed to reveal the patterns of the variations in bacterial diversity and community structure and in nitrogen cycling functional genes along a subalpine meadow degradation gradient on the Loess Plateau, China. Meadow degradation had a significant effect on the beta diversity of soil bacterial communities (P < 0.05) but not on the alpha diversity (P > 0.05). Nonmetric multidimensional scaling (NMDS) and analysis of similarity (ANOSIM) indicated that the compositions of bacterial and plant communities changed remarkably with increasing meadow degradation (all P < 0.05). The beta diversities of the plant and soil bacterial communities were significantly correlated (P < 0.05), while their alpha diversities were weakly correlated (P > 0.05) along the meadow degradation gradient. Redundancy analysis (RDA) showed that the structure of the bacterial community was strongly correlated with total nitrogen (TN), nitrate nitrogen (NO3−-N), plant Shannon diversity, plant coverage, and soil bulk density (all P < 0.05). Moreover, the abundances of N fixation and denitrification genes of the bacterial community decreased along the degradation gradient, but the abundance of nitrification genes increased along the gradient. The structure of the set of N cycling genes present at each site was more sensitive to subalpine meadow degradation than the structure of the total bacterial community. Our findings revealed compositional shifts in the plant and bacterial communities and in the abundances of key N cycling genes as well as the potential drivers of these shifts under different degrees of subalpine meadow degradation. IMPORTANCE Soil microbes play a crucial role in the biogeochemical cycles of grassland ecosystems, yet information on how their community structure and functional characteristics change with subalpine meadow degradation is scarce. In this study, we evaluated the changes in bacterial community structure and nitrogen functional genes in degraded meadow soils. Meadow degradation had a significant effect on bacterial community composition. Soil total nitrogen was the best predictor of bacterial community structure. The beta diversities of the plant and soil bacterial communities were significantly correlated, while their alpha diversities were only weakly correlated. Meadow degradation decreased the potential for nitrogen fixation and denitrification but increased the potential for nitrification. These results have implications for the restoration and reconstruction of subalpine meadow ecosystem on the Loess Plateau.

scholarly journals Local Environmental Factors Drive Divergent Grassland Soil Bacterial Communities in the Western Swiss Alps

2016 ◽  
Vol 82 (21) ◽  
pp. 6303-6316 ◽  
Author(s):  
Erika Yashiro ◽  
Eric Pinto-Figueroa ◽  
Aline Buri ◽  
Jorge E. Spangenberg ◽  
Thierry Adatte ◽  
...  
Keyword(s):  
Community Structure ◽  
Bacterial Community ◽  
Water Content ◽  
Bacterial Diversity ◽  
Bacterial Communities ◽  
Bacterial Community Structure ◽  
Swiss Alps ◽  
Content Type ◽  
Soil Bacterial ◽  
Western Swiss Alps

ABSTRACTMountain ecosystems are characterized by a diverse range of climatic and topographic conditions over short distances and are known to shelter a high biodiversity. Despite important progress, still little is known on bacterial diversity in mountain areas. Here, we investigated soil bacterial biogeography at more than 100 sampling sites randomly stratified across a 700-km2area with 2,200-m elevation gradient in the western Swiss Alps. Bacterial grassland communities were highly diverse, with 12,741 total operational taxonomic units (OTUs) across 100 sites and an average of 2,918 OTUs per site. Bacterial community structure was correlated with local climatic, topographic, and soil physicochemical parameters with high statistical significance. We found pH (correlated with % CaO and % mineral carbon), hydrogen index (correlated with bulk gravimetric water content), and annual average number of frost days during the growing season to be among the groups of the most important environmental drivers of bacterial community structure. In contrast, bacterial community structure was only weakly stratified as a function of elevation. Contrasting patterns were discovered for individual bacterial taxa.Acidobacteriaresponded both positively and negatively to pH extremes. Various families within theBacteroidetesresponded to available phosphorus levels. Different verrucomicrobial groups responded to electrical conductivity, total organic carbon, water content, and mineral carbon contents. Alpine grassland bacterial communities are thus highly diverse, which is likely due to the large variety of different environmental conditions. These results shed new light on the biodiversity of mountain ecosystems, which were already identified as potentially fragile to anthropogenic influences and climate change.IMPORTANCEThis article addresses the question of how microbial communities in alpine regions are dependent on local climatic and soil physicochemical variables. We benefit from a unique 700-km2study region in the western Swiss Alps region, which has been exhaustively studied for macro-organismal and fungal ecology, and for topoclimatic modeling of future ecological trends, but without taking into account soil bacterial diversity. Here, we present an in-depth biogeographical characterization of the bacterial community diversity in this alpine region across 100 randomly stratified sites, using 56 environmental variables. Our exhaustive sampling ensured the detection of ecological trends with high statistical robustness. Our data both confirm previously observed general trends and show many new detailed trends for a wide range of bacterial taxonomic groups and environmental parameters.

scholarly journals Ammonium and Nitrate Shift the Spatial Distribution of Soil Bacterial Communities and Association Networks Along a Distance from Maize Roots in an Acidic Red Soil

2020 ◽  
Author(s):  
Hao Qing Zhang ◽  
Xue Qiang Zhao ◽  
Yu Shi ◽  
Yuting Liang ◽  
Ren Fang Shen
Keyword(s):  
Spatial Distribution ◽  
Community Structure ◽  
Bacterial Community ◽  
Bacterial Diversity ◽  
Soil Ph ◽  
Bacterial Communities ◽  
Root Zone ◽  
Soil Bacterial Communities ◽  
Maize Roots ◽  
Soil Bacterial

Abstract Background: Ammonium (NH4+) and nitrate (NO3−) are two major inorganic nitrogen (N) forms available for plant growth. Soil microbes affect the availability and transformation of these N forms in the rhizosphere, and this affects the N-use efficiency of plants. However, little is known about the responses of the rhizosphere bacterial community structure to NH4+ and NO3−. Here, a rhizobox containing a root zone (root growing area) and various soil compartments (0–0.5 cm, 0.5–1 cm, 1–2 cm, 2–4 cm, and 4–9 cm from the root zone) was designed to investigate the spatial distribution of bacterial diversity, community structure, and co-occurrence patterns along a distance from maize (Zea mays L.) roots with the addition of 15N-labeled NH4+ or NO3− in an acidic red soil.Results: Addition of NH4+ and NO3− reduced soil bacterial diversity in the maize root zone. The structures of soil bacterial communities differed between NH4+ and NO3− in the root zone and 0.5 cm away from the root zone. Soil pH was the major driver of bacterial community assembly during plant uptake of N. Maize roots recruited potentially beneficial acidophilic bacteria (e.g. Acidibacter, Burkholderia, and Catenulispora) under NH4+ treatment, and recruited growth-promoting bacteria that prefer higher pH (e.g. Sphingomonas, Sphingobium, Azospirillum, and Novosphingobium) under NO3− treatment. In the N-fertilization treatments, the soil bacterial networks were more complex in the root zone and its adjacent 0.5–1 cm zone than in other soil compartments. The soil bacterial networks were more complex under NH4+ treatment than under NO3−. More bacterial taxa in the networks responded positively and negatively to soil residual NH4+ than to NO3− in all zones in the rhizobox.Conclusions: The combined effects of the N form and the rhizosphere influenced the spatial patterns and co-occurrence network of soil bacterial communities at different distances from the maize root zone, mainly because of changes in soil pH during the uptake of NH4+ and NO3− by maize roots. Regulating microbial communities by adjusting soil pH through NH4+ and NO3− supply may be an environmentally friendly option for promoting soil microbial functions in intensively managed agro-ecosystems.

scholarly journals Different Responses of Soil Environmental Factors, Soil Bacterial Community, and Root Performance to Reductive Soil Disinfestation and Soil Fumigant Chloropicrin

2021 ◽  
Vol 12 ◽  
Author(s):  
Yu Zhan ◽  
Ning Yan ◽  
Xinyue Miao ◽  
Qiong Li ◽  
Changbao Chen
Keyword(s):  
Community Structure ◽  
Environmental Factors ◽  
Bacterial Community ◽  
Bacterial Diversity ◽  
Bacterial Community Structure ◽  
Treated Soil ◽  
Soil Disinfestation ◽  
Soil Fumigant ◽  
Soil Bacterial ◽  
Soil Environmental Factors

Reductive soil disinfestation (RSD) and soil fumigant chloropicrin (SFC) are two common agricultural strategies for the elimination of soil-borne pathogens. However, the differences in soil environmental factors, soil bacterial microbiome, and root performance between SFC and RSD are poorly understood. In this study, three soil treatments, untreated control (CK), SFC with 0.5 t⋅ha–1 chloropicrin, and RSD with 15 t⋅ha–1 animal feces, were compared. We evaluated their effects on soil environmental factors, bacterial community structure, and root activity using chemical analysis and high-throughput sequencing. RSD treatment improved soil composition structure, bacterial diversity, and root performance to a greater extent. Carbon source utilization preference and bacterial community structure were strikingly altered by SFC and RSD practices. Bacterial richness, diversity, and evenness were notably lowered in the SFC- and RSD-treated soil compared with the CK-treated soil. However, RSD-treated soil harbored distinct unique and core microbiomes that were composed of more abundant and diverse potentially disease-suppressive and organic-decomposable agents. Also, soil bacterial diversity and composition were closely related to soil physicochemical properties and enzyme activity, of which pH, available Na (ANa), available Mg (AMg), available Mn (AMn), total Na (TNa), total Ca (TCa), total Cu (TCu), total Sr (TSr), urease (S-UE), acid phosphatase (S-ACP), and sucrase (S-SC) were the main drivers. Moreover, RSD treatment also significantly increased ginseng root activity. Collectively, these results suggest that RSD practices could considerably restore soil nutrient structure and bacterial diversity and improve root performance, which can be applied as a potential agricultural practice for the development of disease-suppressive soil.

scholarly journals Agricultural practice negatively affects soil microbial diversity and nitrogen functional genes comparing to adjacent native forest soils

2021 ◽  
Author(s):  
Tiehang Wu ◽  
Michael Sabula ◽  
Holli Milner ◽  
Gary Strickland ◽  
Gan Liu
Keyword(s):  
Community Structure ◽  
Bacterial Diversity ◽  
Forest Soils ◽  
Agricultural Practices ◽  
Functional Genes ◽  
Agricultural Practice ◽  
Soil Bacterial Diversity ◽  
Soil Microbial Diversity ◽  
Soil Microbial ◽  
Soil Bacterial

Soil microbial diversity and community are determined by anthropogenic activities and environmental conditions, which greatly affect the functioning of ecosystem. We investigated the soil bacterial diversity, communities, and nitrogen (N) functional genes with different disturbance intensity levels from crop, transition, to forest soils at three locations in the coastal region of Georgia, USA. Illumina high-throughput DNA sequencing based on bacterial 16S rRNA genes were performed for bacterial diversity and community analyses. Nitrifying (AOB amoA) and denitrifying (nirK) functional genes were further detected using quantitative PCR (qPCR) and Denaturing Gradient Gel Electrophoresis (DGGE). Soil bacterial community structure determined by Illumina sequences were significantly different between crop and forest soils (p < 0.01), as well as between crop and transition soils (p = 0.01). However, there is no difference between transition and forest soils. Compared to less disturbed forest, agricultural practice significantly decreased soil bacterial richness and Shannon diversity. Soil pH and nitrate contents together contributed highest for the observed different bacterial communities (Correlations = 0.381). Two OTUs (OTU5, OTU8) belonging to Acidobacteriales species decreased in crop soils, however, agricultural practices significantly increased an OTU (OTU4) of Nitrobacteraceae. The relative abundance of AOB amoA gene was significantly higher in crop soils than in forest and transition soils. Distinct grouping of soil denitrifying bacterial nirK communities was observed and agricultural practices significantly decreased the diversity of nirK gene compared to forest soils. Anthropogenic effects through agricultural practices negatively affecting the soil bacterial diversity, community structure, and N functional genes.

scholarly journals Successional trajectory of bacterial communities in soil are shaped by plant-driven changes during secondary succession

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Mayank Krishna ◽  
Shruti Gupta ◽  
Manuel Delgado – Baquerizo ◽  
Elly Morriën ◽  
Satish Chandra Garkoti ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Bacterial Diversity ◽  
Community Composition ◽  
Bacterial Communities ◽  
Secondary Succession ◽  
Positive Association ◽  
Ecological Networks ◽  
Growth Stages ◽  
Ecosystem Recovery ◽  
Soil Bacterial

Abstract This study investigated the potential role of a nitrogen-fixing early-coloniser Alnus Nepalensis D. Don (alder) in driving the changes in soil bacterial communities during secondary succession. We found that bacterial diversity was positively associated with alder growth during course of ecosystem development. Alder development elicited multiple changes in bacterial community composition and ecological networks. For example, the initial dominance of actinobacteria within bacterial community transitioned to the dominance of proteobacteria with stand development. Ecological networks approximating species associations tend to stabilize with alder growth. Janthinobacterium lividum, Candidatus Xiphinematobacter and Rhodoplanes were indicator species of different growth stages of alder. While the growth stages of alder has a major independent contribution to the bacterial diversity, its influence on the community composition was explained conjointly by the changes in soil properties with alder. Alder growth increased trace mineral element concentrations in the soil and explained 63% of variance in the Shannon-diversity. We also found positive association of alder with late-successional Quercus leucotrichophora (Oak). Together, the changes in soil bacterial community shaped by early-coloniser alder and its positive association with late-successional oak suggests a crucial role played by alder in ecosystem recovery of degraded habitats.

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