scholarly journals Assessing soil bacterial community and dynamics by integrated high-throughput absolute abundance quantification

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e4514 ◽  
Author(s):  
Jun Lou ◽  
Li Yang ◽  
Haizhen Wang ◽  
Laosheng Wu ◽  
Jianming Xu

Microbial ecological studies have been remarkably promoted by the high-throughput sequencing approach with explosive information of taxonomy and relative abundance. However, relative abundance does not reflect the quantity of the microbial community and the inter-sample differences among taxa. In this study, we refined and applied an integrated high-throughput absolute abundance quantification (iHAAQ) method to better characterize soil quantitative bacterial community through combining the relative abundance (by high-throughput sequencing) and total bacterial quantities (by quantitative PCR). The proposed iHAAQ method was validated by an internal reference strain EDL933 and a laboratory strain WG5. Application of the iHAAQ method to a soil phenanthrene biodegradation study showed that for some bacterial taxa, the changes of relative and absolute abundances were coincident, while for others the changes were opposite. With the addition of a microbial activity inhibitor (NaN3), the absolute abundances of soil bacterial taxa, including several dominant genera of Bacillus, Flavobacterium, and Paenibacillus, decreased significantly, but their relative abundances increased after 28 days of incubation. We conclude that the iHAAQ method can offer more comprehensive information to reflect the dynamics of soil bacterial community with both relative and absolute abundances than the relative abundance from high-throughput sequencing alone.

2020 ◽  
Author(s):  
Han-Wen Deng ◽  
Xin-Fu Bai ◽  
Ping Zhu ◽  
Yu-Meng Lu ◽  
Lei Ji ◽  
...  

Abstract Background Grazing exclusion is a common grassland management strategy for restoring degraded grasslands. Its effectiveness on optimizing plant species community, increasing vegetation diversity and biomass, improving soil fertility, has been widely documented in literatures. However, little is known on the responses of the absolute abundance and the ecological functions of soil bacterial community to long-term grazing exclusion. Result In this study, the absolute abundance, diversity, and ecological functions of soil bacterial community were determined by the high-throughput absolute quantitative sequencing technology on a long-term grazing exclusion (40 years, GE) area and three free grazing areas (FGs) within a Leymus chinensis steppe of Inner Mongolia, China, and analyzed the driving forces leading to the variations in soil bacterial community and functions. Our results showed that there was significantly higher soil bacterial abundance in the GE than the FGs along with corresponding variations in vegetation and soil properties. With the decrease of vegetation aboveground biomass, the absolute abundance of soil bacterial community also decreased. Among the phyla of the soil bacterial communities, the relative abundances of Chloroflexi and Firmicutes phyla were especially lower, and that of Verrucomicrobia phylum was higher in the GE than the FGs; the absolute abundances of Euryarchaeota and Microgenomates phyla were especially higher in the GE than the FGs. Conclusions This study suggested that long-term grazing exclusion significantly increased the absolute abundance, changed soil bacterial composition, and especially enhanced bacterial motility and chemotaxis. In particular, soil organic matter was the important agent to influence and connect vegetation and soil. This work will enrich our understanding of the responses of absolute abundance, diversity, and function of the soil bacterial community to long-term grazing exclusion, and help the evaluation of grassland degradation degree and restoration strategy effectiveness.


Diversity ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 317
Author(s):  
Meide Zhang ◽  
Yinsheng He ◽  
Wuxian Zhou ◽  
Lunqiang Ai ◽  
Haihua Liu ◽  
...  

Codonopsis tangshen, a perennial herbaceous, has been shown to be affected by continuous cropping, with significant decline in both yield and quality. In this study, we studied the effect of continuous cropping on the abundance and composition of rhizospheric soil bacterial community. Results showed that continuous cropping causes a significant decline in both yield and quality. The nutrient content in continuous cropping soil was higher than that of soil in main cropping. Pyrosequencing analyses revealed Proteobacteria and Acidobacteria as the main phyla in two types of soils. Relative abundance of Acidobacteria, Nitrospirae, TM7, and AD3 phyla was observed to be high in continuous cropping soils, whereas Chloroflexi, Bacteroidetes, and Planctomycetes phyla were richer in main cropping soils. At the genus level, high relative abundance of Pseudomonas (γ-Proteobacteria), Rhodanobacter, Candidatus Koribacter, and Candidatus were observed in continuous cropping soil. Different patterns of bacterial community structure were observed between different soils. Redundancy analysis indicated that organic matter content and available nitrogen content exhibited the strongest effect on bacterial community structure in the continuous cropping soil. Taken together, continuous cropping led to a significant decline in yield and quality, decrease in rhizospheric soil bacterial abundance, and alteration of rhizospheric soil microbial community structure, thereby resulting in poor growth of C. tangshen in the continuous cropping system.


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.


2021 ◽  
Author(s):  
Zhuxiu Liu ◽  
Haidong Gu ◽  
Aizhen Liang ◽  
Lujun Li ◽  
Qin Yao ◽  
...  

Abstract Aims Conventional tillage is a serious threat to the stability of soil ecosystems. Understanding the response mechanisms of soil microbial community assemblies to anthropogenic activities is a major topic of ecological research. Methods Here, we investigated the bacterial community structures and assemblies in bulk and rhizosphere soils of soybeans grown with conventional tillage (moldboard plow, MP) and with conservation tillage that involved no-tillage (NT) or ridge tillage (RT) using high-throughput sequencing methods. Results We found that soil bacterial community compositions, structures and assembly processes were primarily altered by tillage practices. Briefly, in comparison to MP, NT and RT increased the relative abundances of the nitrogen-fixing bacteria Mesorhizobium sp., Bradyrhizobium sp. and Burkholderia sp., but decreased the abundance of soil carbon-degrading bacteria, especially Blastococcus sp., Streptomyces sp. and Sphingomonas sp. In addition, in comparison to MP, NT and RT resulted in more stable bacterial networks and more lower the relative contribution of homogenizing dispersal. Soil pH was the primary soil factor regulating both the bacterial community structures and assembly processes under the three tillage practices. Conclusions The altered functional bacteria under conservation tillage was mostly affiliated with biomarkers and keystone taxa, inferring that conservation tillage might contribute to biological nitrogen fixation and soil carbon sequestration.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9122
Author(s):  
Li Chen ◽  
Yuzhu Li ◽  
Lei Jin ◽  
Li He ◽  
Xiaolin Ao ◽  
...  

“Yibin Baijiu” (YB) is a special Chinese strong-aroma Baijiu (CSAB) that originated in Yibin, a city in western China. YB is fermented in cellars lined with pit mud (PM), the microbiota in which may affect YB quality. In this study, high throughput sequencing of the 16S rRNA gene was used to demonstrate the bacterial community structure and diversity in PM of YB. In addition, the physicochemical characteristics of PM were also analyzed, including moisture content, pH, and available phosphorous, ammonia nitrogen, and humic acid levels. Results showed that Firmicutes was the dominant phylum in all PM samples with abundance > 70.0%, followed by Euryarchaeota (11.3%), Bacteroidetes (6.5%), Synergistetes (3.0%), Actinobacteria (1.4%), and Proteobacteria (1.2%). Furthermore, 14 different genera with average relative abundance of > 1% were detected. The Chao1 and Shannon indexes did not vary significantly between the sub-layer and middle-layer PM (P > 0.05). However, Linear discriminant analysis Effect Size (LEfSe) analysis showed that the relative abundance of Lactobacillus in the sub-layer PM was significantly higher than in middle-layer PM. pH differed significantly (P < 0.05) between the two groups. Canonical correspondence analysis revealed that bacterial community in PM correlated significantly with available phosphorous content and pH. Our study provides basic data for further elucidating the diversity of microbiota in the PM of YB and the potential mechanism of Baijiu production.


Sign in / Sign up

Export Citation Format

Share Document