scholarly journals Changes in the Soil Bacterial Community in a Chronosequence of Temperate Walnut-Based Intercropping Systems

Forests ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 299 ◽  
Author(s):  
Pengxiang Gao ◽  
Xiaofeng Zheng ◽  
Lai Wang ◽  
Bin Liu ◽  
Shuoxin Zhang

Agroforestry (tree-based intercropping) is regarded as a promising practice in sustainable agricultural management. However, the impacts of converting cropland to an agroforestry system on microbial communities remain poorly understood. In this study, we assessed the soil bacterial communities in conventional wheat monoculture systems and a chronosequence (5–14 years) walnut-wheat agroforestry system through the high-throughput sequencing of 16S rRNA genes to investigate the effect of agroforestry age on soil bacterial communities and the correlation between soil properties and bacterial communities in the agroecosystem. Our results demonstrate that establishing and developing walnut tree-based agroforestry increased soil bacterial diversity and changed bacterial community structure. Firmicutes, Proteobacteria, Actinobacteria and Acidobacteria were the dominant soil bacterial phyla and Bacillus was the dominant genus. Crop monoculture systems were characterized by the Bacillus (Firmicutes)-dominated microbial community. The relative abundance of Bacillus decreased with agroforestry age; however, subgroups of Proteobacteria and Actinobacteria increased. Of the selected soil physicochemical properties, soil pH and bulk density were significantly correlated with bacterial alpha diversity, and soil pH and organic carbon were the principal drivers in shaping the soil microbial structure as revealed by redundancy analysis (RDA).

2006 ◽  
Vol 72 (3) ◽  
pp. 1852-1857 ◽  
Author(s):  
Michelle Sait ◽  
Kathryn E. R. Davis ◽  
Peter H. Janssen

ABSTRACT The pH strongly influenced the development of colonies by members of subdivision 1 of the phylum Acidobacteria on solid laboratory media. Significantly more colonies of this group formed at pH 5.5 than at pH 7.0. At pH 5.5, 7 to 8% of colonies that formed on plates that were incubated for 4 months were formed by subdivision 1 acidobacteria. These colonies were formed by bacteria that spanned almost the entire phylogenetic breadth of the subdivision, and there was considerable congruence between the diversity of this group as determined by the cultivation-based method and by surveying 16S rRNA genes in the same soil. Members of subdivision 1 acidobacteria therefore appear to be readily culturable. An analysis of published libraries of 16S rRNAs or 16S rRNA genes showed a very strong correlation between the abundance of subdivision 1 acidobacteria in soil bacterial communities and the soil pH. Subdivision 1 acidobacteria were most abundant in libraries from soils with pHs of <6, but rare or absent in libraries from soils with pHs of >6.5. This, together with the selective cultivation of members of the group on lower-pH media, indicates that growth of many members of subdivision 1 acidobacteria is favored by slightly to moderately acidic growth conditions.


2009 ◽  
Vol 75 (15) ◽  
pp. 5111-5120 ◽  
Author(s):  
Christian L. Lauber ◽  
Micah Hamady ◽  
Rob Knight ◽  
Noah Fierer

ABSTRACT Soils harbor enormously diverse bacterial populations, and soil bacterial communities can vary greatly in composition across space. However, our understanding of the specific changes in soil bacterial community structure that occur across larger spatial scales is limited because most previous work has focused on either surveying a relatively small number of soils in detail or analyzing a larger number of soils with techniques that provide little detail about the phylogenetic structure of the bacterial communities. Here we used a bar-coded pyrosequencing technique to characterize bacterial communities in 88 soils from across North and South America, obtaining an average of 1,501 sequences per soil. We found that overall bacterial community composition, as measured by pairwise UniFrac distances, was significantly correlated with differences in soil pH (r = 0.79), largely driven by changes in the relative abundances of Acidobacteria, Actinobacteria, and Bacteroidetes across the range of soil pHs. In addition, soil pH explains a significant portion of the variability associated with observed changes in the phylogenetic structure within each dominant lineage. The overall phylogenetic diversity of the bacterial communities was also correlated with soil pH (R2 = 0.50), with peak diversity in soils with near-neutral pHs. Together, these results suggest that the structure of soil bacterial communities is predictable, to some degree, across larger spatial scales, and the effect of soil pH on bacterial community composition is evident at even relatively coarse levels of taxonomic resolution.


2004 ◽  
Vol 70 (9) ◽  
pp. 5057-5065 ◽  
Author(s):  
Evelyn Hackl ◽  
Sophie Zechmeister-Boltenstern ◽  
Levente Bodrossy ◽  
Angela Sessitsch

ABSTRACT The diversity and composition of soil bacterial communities were compared among six Austrian natural forests, including oak-hornbeam, spruce-fir-beech, and Austrian pine forests, using terminal restriction fragment length polymorphism (T-RFLP, or TRF) analysis and sequence analysis of 16S rRNA genes. The forests studied differ greatly in soil chemical characteristics, microbial biomass, and nutrient turnover rates. The aim of this study was to relate these differences to the composition of the bacterial communities inhabiting the individual forest soils. Both TRF profiling and clone sequence analysis revealed that the bacterial communities in soils under Austrian pine forests, representing azonal forest types, were distinct from those in soils under zonal oak-hornbeam and spruce-fir-beech forests, which were more similar in community composition. Clones derived from an Austrian pine forest soil were mostly affiliated with high-G+C gram-positive bacteria (49%), followed by members of the α-Proteobacteria (20%) and the Holophaga/Acidobacterium group (12%). Clones in libraries from oak-hornbeam and spruce-fir-beech forest soils were mainly related to the Holophaga/Acidobacterium group (28 and 35%), followed by members of the Verrucomicrobia (24%) and the α-Proteobacteria (27%), respectively. The soil bacterial communities in forests with distinct vegetational and soil chemical properties appeared to be well differentiated based on 16S rRNA gene phylogeny. In particular, the outstanding position of the Austrian pine forests, which are determined by specific soil conditions, was reflected in the bacterial community composition.


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.


2019 ◽  
Vol 131 ◽  
pp. 01091
Author(s):  
Jie Hong ◽  
Yue Yang ◽  
Yi Gao ◽  
LianQuan Zhong ◽  
QuanMing Xu ◽  
...  

The variation of bacterial community in lettuce continuous cropping was determined by high throughput sequencing. During the continuous planting of lettuce, the richness and diversity of bacterial communities in the soil increased, and the ACE index and Chao index increased by 40.21 % and 36.91 %, respectively. The proportion of Actinobacteria, Chloroflexi, Firmicutes and Nitrospirae in the soil increased, while the abundance of Acidobacteria, Bacteroidetes, Gemmatimonadetes, Planctomycetes and Proteobacteria gradually declined. And the abundance in the soil accounting for 1 % of the dominant bacterial genera increased to 11, among them, Anaerolinea, Bacillus, Nitrosomonas, and Xanthomonas etc became the dominant bacterium genus in the soil after lettuce continuous cropping. After the lettuce had been planted 8 times, the yield decreased by 21.20 % compared to the first harvest. Lettuce continuous cropping had an effect on bacterial community and lettuce yield to some extent.


PLoS ONE ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. e0246919
Author(s):  
Lukas Beule ◽  
Petr Karlovsky

Background Tree-based intercropping (agroforestry) has been advocated to reduce adverse environmental impacts of conventional arable cropping. Modern agroforestry systems in the temperate zone are alley-cropping systems that combine rows of fast-growing trees with rows of arable crops. Soil microbial communities in these systems have been investigated intensively; however, molecular studies with high taxonomical resolution are scarce. Methods Here, we assessed the effect of temperate agroforestry on the abundance, diversity and composition of soil bacterial communities at three paired poplar-based alley cropping and conventional monoculture cropland systems using real-time PCR and Illumina sequencing of bacterial 16S rRNA genes. Two of the three systems grew summer barley (Hordeum vulgare); one system grew maize (Zea mays) in the sampling year. To capture the spatial heterogeneity induced by the tree rows, soil samples in the agroforestry systems were collected along transects spanning from the centre of the tree rows to the centre of the agroforestry crop rows. Results Tree rows of temperate agroforestry systems increased the abundance of soil bacteria while their alpha diversity remained largely unaffected. The composition of the bacterial communities in tree rows differed from those in arable land (crop rows of the agroforestry systems and conventional monoculture croplands). Several bacterial groups in soil showed strong association with either tree rows or arable land, revealing that the introduction of trees into arable land through agroforestry is accompanied by the introduction of a tree row-associated microbiome. Conclusion The presence of tree row-associated bacteria in agroforestry increases the overall microbial diversity of the system. We speculate that the increase in biodiversity is accompanied by functional diversification. Differences in plant-derived nutrients (root exudates and tree litter) and management practices (fertilization and tillage) likely account for the differences between bacterial communities of tree rows and arable land in agroforestry systems.


2019 ◽  
Author(s):  
Juanjuan Fu ◽  
Yilan Luo ◽  
Pengyue Sun ◽  
Jinzhu Gao ◽  
Donghao Zhao ◽  
...  

Abstract Background: Perturbations in the abiotic stress directly or indirectly affect plants and root-associated microbial communities. Shade stress presents one of the major abiotic limitations for turfgrass growth, as light availability is severely reduced under a leaf canopy. Studies have shown that shade stress influences plant growth and alters plant metabolism, yet little is known about how it affects the structure of rhizosphere soil bacterial communities. In this study, a glasshouse experiment was conducted to examine the impact of shade stress on the physiology of two contrasting shade-tolerant turfgrasses and their rhizosphere soil microbes. Shade-tolerant dwarf lilyturf (Ophiopogon japonicus, OJ) and shade-intolerant perennial turf-type ryegrasss (Lolium perenne, LP) were used. Bacterial community composition was assayed using high-throughput sequencing. Results: Our physiochemical data showed that under shade stress, OJ maintained higher photosynthetic capacity and root growth, thus OJ was found to be more shade-tolerant than LP. Illumina sequencing data revealed that shade stress had little impact on the diversity of the OJ and LP’s bacterial communities, but instead impacted the composition of bacterial communities. The bacterial communities were mostly composed of Proteobacteria and Acidobacteria in OJ soil. Further pairwise fitting analysis showed that a positive correlation of shade-tolerance in two turfgrasses and their bacterial community compositions. Several soil properties (NO3--N, NH4+-N, AK) showed a tight coupling with several major bacterial communities under shade stress, indicating that they are important drivers determining bacterial community structures. Moreover, OJ shared core bacterial taxa known to promote plant growth and confer tolerance to shade stress, which suggests common principles underpinning OJ-microbe interactions. Conclusion: OJ was more shade-tolerant than LP. Shifts in rhizosphere soil bacterial community structure play a vital role in shade-tolerance of OJ plants.


2020 ◽  
Author(s):  
Hao Qing Zhang ◽  
Xue Qiang Zhao ◽  
Yu Shi ◽  
Yuting Liang ◽  
Ren Fang Shen

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.


2021 ◽  
Vol 12 ◽  
Author(s):  
Tingwen Huang ◽  
Weiguo Liu ◽  
Xi-En Long ◽  
Yangyang Jia ◽  
Xiyuan Wang ◽  
...  

Bacterial communities in soil serve an important role in controlling terrestrial biogeochemical cycles and ecosystem processes. Increased nitrogen (N) deposition in Northwest China is generating quantifiable changes in many elements of the desert environment, but the impacts of N deposition, as well as seasonal variations, on soil bacterial community composition and structure are poorly understood. We used high-throughput sequencing of bacterial 16S rRNA genes from Gurbantünggüt Desert moss crust soils to study the impacts of N addition on soil bacterial communities in March, May, and November. In November, we discovered that the OTU richness and diversity of soil bacterial community dropped linearly with increasing N input. In November and March, the diversity of the soil bacterial community decreased significantly in the medium-N and high-N treatments. In May, N addition caused a substantial change in the makeup of the soil bacterial composition, while the impacts were far less apparent in November and March. Furthermore, the relative abundance of major bacterial phyla reacted non-linearly to N addition, with high-N additions decreasing the relative richness of Proteobacteria, Bacteroidetes, and Acidobacteria while increasing the relative abundance of Actinobacteria and Chloroflexi. We also discovered that seasonality, as characterized by changes in soil moisture, pH, SOC, and AK content, had a significant impact on soil bacterial communities. Significant variations in the makeup of the community were discovered at the phylum and genus levels throughout the various months. In May, the variety of soil bacterial community was at its peak. Further investigation showed that the decrease in soil bacterial diversity was mostly attributed to a drop in soil pH. These results indicated that the impact of N deposition on the soil bacterial community was seasonally dependent, suggesting that future research should evaluate more than one sample season at the same time.


2019 ◽  
Vol 20 (3) ◽  
pp. 811-818
Author(s):  
MARINI WIJAYANTI ◽  
ARIS TRI WAHYUDI ◽  
MUNTI YUHANA ◽  
MARTIN ENGELHAUPT ◽  
ANJA MERYANDINI

Abstract. Wijayanti M, Wahyudi AT, Yuhana M, Engelhaupt M, Meryandini A. 2019. Impact of Bukit Dua Belas rainforest transformation to oil palm plantation on phylogenetic of soil bacterial communities in Sarolangun, Jambi, Sumatra, Indonesia. Biodiversitas 20: 811-818. Land use change from forest to oil palm plantation at Sumatra could decrease biodiversity, including bacterial diversity. The case of Bukit Dua Belas transformation from forest to oil palm plantation was gotten for measuring shift community of soil bacterial in both areas. The diversity of bacterial communities from rainforest and oil palm plantation topsoil in Sumatra was studied using pyrosequencing of 16S rRNA gene and common biodiversity indices. Phylogenetic approach was used to reveal the community shift of bacterial phyla and genera in both areas. Ecological approach was carried out by measuring soil pH, TC (total carbon), TN (total nitrogen), AP (available phosphorous), bacterial diversity with Shannon and Simpson indices, and bacterial richness with Chao1-ACE index and OTUs. Bacterial diversity and richness on lowland forest topsoil and oil palm plantation soil were not different, as soil pH, TC, and TN as substrate factors were not different significantly. The majority of sequences related to Acidobacteria (56.33%), Proteobacteria (27.43%), Actinobacteria (7.11%), and Cyanobacteria (5.55%) were from forest; whereas those related to Acidobacteria (50.11%), Proteobacteria (31.63%), Actinobacteria (7.58%), Chloroflexi (2.60%), and Gemmatimonadetes (2.71%) invented from oil palm plantation. Acidobacteria was the most dominant phyla in both habitats, because soil pH in both areas was acidic (3.77 - 4.80 pHH2O). The genera of alpha-proteobacteria dominated in genera phylotype of bacterial 16S rRNA phylogenetic revealed in both forest and oil palm plantation topsoil. The most genera in phylogenetic tree are Burkholderia from Beta-proteobacteria. The bacterial community shift occurred in forest transformation, even though the oil palm plantation showed more bacterial phyla and genera than the lowland rainforest.


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