scholarly journals Organic Amendments to Avocado Crops Induce Suppressiveness and Influence the Composition and Activity of Soil Microbial Communities

2015 ◽  
Vol 81 (10) ◽  
pp. 3405-3418 ◽  
Author(s):  
Nuria Bonilla ◽  
Carmen Vida ◽  
Maira Martínez-Alonso ◽  
Blanca B. Landa ◽  
Nuria Gaju ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Microbial Communities ◽  
Root Rot ◽  
Bacterial Community Composition ◽  
Soil Microbial Communities ◽  
Organic Amendments ◽  
Bulk Soil ◽  
White Root Rot ◽  
Content Type ◽  
Soil Microbial

ABSTRACTOne of the main avocado diseases in southern Spain is white root rot caused by the fungusRosellinia necatrixPrill. The use of organic soil amendments to enhance the suppressiveness of natural soil is an inviting approach that has successfully controlled other soilborne pathogens. This study tested the suppressive capacity of different organic amendments againstR. necatrixand analyzed their effects on soil microbial communities and enzymatic activities. Two-year-old avocado trees were grown in soil treated with composted organic amendments and then used for inoculation assays. All of the organic treatments reduced disease development in comparison to unamended control soil, especially yard waste (YW) and almond shells (AS). The YW had a strong effect on microbial communities in bulk soil and produced larger population levels and diversity, higher hydrolytic activity and strong changes in the bacterial community composition of bulk soil, suggesting a mechanism of general suppression. Amendment with AS induced more subtle changes in bacterial community composition and specific enzymatic activities, with the strongest effects observed in the rhizosphere. Even if the effect was not strong, the changes caused by AS in bulk soil microbiota were related to the direct inhibition ofR. necatrixby this amendment, most likely being connected to specific populations able to recolonize conducive soil after pasteurization. All of the organic amendments assayed in this study were able to suppress white root rot, although their suppressiveness appears to be mediated differentially.

scholarly journals The effects of soil depth on the structure of microbial communities in agricultural soils in Iowa, USA

2020 ◽  
Author(s):  
Jingjie Hao ◽  
Yen Ning Chai ◽  
Raziel A. Ordóñez ◽  
Emily E. Wright ◽  
Sotirios Archontoulis ◽  
...  
Keyword(s):  
Community Structure ◽  
Microbial Community ◽  
Bacterial Community ◽  
Microbial Communities ◽  
Community Composition ◽  
Microbial Community Structure ◽  
Soil Depth ◽  
Bacterial Community Composition ◽  
Soil Microbial Communities ◽  
Soil Microbial

AbstractThe determination of how microbial community structure changes within the soil profile, will be beneficial to understanding the long-term health of agricultural soil ecosystems and will provide a first step towards elucidating how deep soil microbial communities contribute to carbon sequestration. This study aimed to investigate the differences in the microbial community abundance, composition and diversity throughout from the surface layers down to deep soils in corn and soybean fields in Iowa, USA. We used 16S rRNA amplicon sequencing of soil samples to characterize the change in microbial community structure. Our results revealed decreased richness and diversity in bacterial community structure with increasing soil depth. We also observed distinct distribution patterns of bacterial community composition along soil profiles. Soil and root data at different depths enabled us to demonstrate that the soil organic matter, soil bulk density and plant water availability were all significant factors in explaining the variation in soil microbial community composition. Our findings provide valuable insights in the changes in microbial community structure to depths of 180 cm in one of the most productive agricultural regions in the world. This knowledge will be important for future management and productivity of agroecosystems in the face of increasing demand for food and climate change.

Alkaline soil pH affects bulk soil, rhizosphere and root endosphere microbiomes of plants growing in a Sandhills ecosystem

2021 ◽  
Vol 97 (4) ◽  
Author(s):  
Lucas Dantas Lopes ◽  
Jingjie Hao ◽  
Daniel P Schachtman
Keyword(s):  
Microbial Communities ◽  
Plant Species ◽  
Soil Ph ◽  
Soil Microbial Communities ◽  
Bulk Soil ◽  
Strong Impact ◽  
Alkaline Soil ◽  
Alkaline Soils ◽  
Soil Microbial ◽  
Soil Rhizosphere

ABSTRACT Soil pH is a major factor shaping bulk soil microbial communities. However, it is unclear whether the belowground microbial habitats shaped by plants (e.g. rhizosphere and root endosphere) are also affected by soil pH. We investigated this question by comparing the microbial communities associated with plants growing in neutral and strongly alkaline soils in the Sandhills, which is the largest sand dune complex in the northern hemisphere. Bulk soil, rhizosphere and root endosphere DNA were extracted from multiple plant species and analyzed using 16S rRNA amplicon sequencing. Results showed that rhizosphere, root endosphere and bulk soil microbiomes were different in the contrasting soil pH ranges. The strongest impact of plant species on the belowground microbiomes was in alkaline soils, suggesting a greater selective effect under alkali stress. Evaluation of soil chemical components showed that in addition to soil pH, cation exchange capacity also had a strong impact on shaping bulk soil microbial communities. This study extends our knowledge regarding the importance of pH to microbial ecology showing that root endosphere and rhizosphere microbial communities were also influenced by this soil component, and highlights the important role that plants play particularly in shaping the belowground microbiomes in alkaline soils.

scholarly journals Intercropping with Potato-Onion Enhanced the Soil Microbial Diversity of Tomato

2020 ◽  
Vol 8 (6) ◽  
pp. 834
Author(s):  
Naihui Li ◽  
Danmei Gao ◽  
Xingang Zhou ◽  
Shaocan Chen ◽  
Chunxia Li ◽  
...  
Keyword(s):  
Community Structure ◽  
Organic Carbon ◽  
Bacterial Community ◽  
Soil Organic Carbon ◽  
Microbial Communities ◽  
Fungal Community ◽  
Soil Microbial Communities ◽  
Tomato Seedling ◽  
Soil Microbial ◽  
Potato Onion

Intercropping can achieve sustainable agricultural development by increasing plant diversity. In this study, we investigated the effects of tomato monoculture and tomato/potato-onion intercropping systems on tomato seedling growth and changes of soil microbial communities in greenhouse conditions. Results showed that the intercropping with potato-onion increased tomato seedling biomass. Compared with monoculture system, the alpha diversity of soil bacterial and fungal communities, beta diversity and abundance of bacterial community were increased in the intercropping system. Nevertheless, the beta-diversity and abundance of fungal community had no difference between the intercropping and monoculture systems. The relative abundances of some taxa (i.e., Acidobacteria-Subgroup-6, Arthrobacter, Bacillus, Pseudomonas) and several OTUs with the potential to promote plant growth were increased, while the relative abundances of some potential plant pathogens (i.e., Cladosporium) were decreased in the intercropping system. Redundancy analysis indicated that bacterial community structure was significantly influenced by soil organic carbon and pH, the fungal community structure was related to changes in soil organic carbon and available phosphorus. Overall, our results suggested that the tomato/potato-onion intercropping system altered soil microbial communities and improved the soil environment, which may be the main factor in promoting tomato growth.

scholarly journals Effects of Wildfire and Harvest Disturbances on Forest Soil Bacterial Communities

2007 ◽  
Vol 74 (1) ◽  
pp. 216-224 ◽  
Author(s):  
Nancy R. Smith ◽  
Barbara E. Kishchuk ◽  
William W. Mohn
Keyword(s):  
Microbial Biomass ◽  
Microbial Communities ◽  
Community Composition ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Microbial Biomass Carbon ◽  
Bacterial Community Composition ◽  
Soil Microbial Communities ◽  
Rrna Gene ◽  
Microbial Biomass Nitrogen ◽  
Soil Microbial

ABSTRACT Wildfires and harvesting are important disturbances to forest ecosystems, but their effects on soil microbial communities are not well characterized and have not previously been compared directly. This study was conducted at sites with similar soil, climatic, and other properties in a spruce-dominated boreal forest near Chisholm, Alberta, Canada. Soil microbial communities were assessed following four treatments: control, harvest, burn, and burn plus timber salvage (burn-salvage). Burn treatments were at sites affected by a large wildfire in May 2001, and the communities were sampled 1 year after the fire. Microbial biomass carbon decreased 18%, 74%, and 53% in the harvest, burn, and burn-salvage treatments, respectively. Microbial biomass nitrogen decreased 25% in the harvest treatment, but increased in the burn treatments, probably because of microbial assimilation of the increased amounts of available NH4 + and NO3 − due to burning. Bacterial community composition was analyzed by nonparametric ordination of molecular fingerprint data of 119 samples from both ribosomal intergenic spacer analysis (RISA) and rRNA gene denaturing gradient gel electrophoresis. On the basis of multiresponse permutation procedures, community composition was significantly different among all treatments, with the greatest differences between the two burned treatments versus the two unburned treatments. The sequencing of DNA bands from RISA fingerprints revealed distinct distributions of bacterial divisions among the treatments. Gamma- and Alphaproteobacteria were highly characteristic of the unburned treatments, while Betaproteobacteria and members of Bacillus were highly characteristic of the burned treatments. Wildfire had distinct and more pronounced effects on the soil microbial community than did harvesting.

scholarly journals Short-Term Effects of Different Forest Management Methods on Soil Microbial Communities of a Natural Quercus aliena var. acuteserrata Forest in Xiaolongshan, China

Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 161 ◽  
Author(s):  
Pan Wan ◽  
Gongqiao Zhang ◽  
Zhonghua Zhao ◽  
Yanbo Hu ◽  
Wenzhen Liu ◽  
...  
Keyword(s):  
Microbial Community ◽  
Forest Management ◽  
Bacterial Community ◽  
Microbial Communities ◽  
Relative Abundance ◽  
Fungal Community ◽  
Soil Microbial Community ◽  
Soil Microbial Communities ◽  
Short Term ◽  
Soil Microbial

One of the aims of sustainable forest management is to preserve the diversity and resilience of ecosystems. Unfortunately, changes in the soil microbial communities after forest management remain unclear. We analyzed and compared the soil microbial community of a natural Quercus aliena var. acuteserrata forest after four years of four different management methods using high-throughput sequencing technology. The forest management methods were close-to-nature management (CNFM), structure-based forest management (SBFM), secondary forest comprehensive silviculture (SFCS) and unmanaged control (CK). The results showed that: (1) the soil microbial community diversity indices were not significantly different among the different management methods. (2) The relative abundance of Proteobacteria in the SBFM treatment was lower than in the CK treatment, while the relative abundance of Acidobacteria in the SBFM was significantly higher than that in the CK treatment. The relative abundance of Ascomycota was highest in the CNFM treatment, and that of Basidiomycota was lowest in the CNFM treatment. However, the relative abundance of dominant bacterial and fungal phyla was not significantly different in CK and SFCS. (3) Redundancy analysis (RDA) showed that the soil organic matter (SOM), total nitrogen (TN), and available nitrogen (AN) significantly correlated with the bacterial communities, and the available potassium (AK) was the only soil nutrient, which significantly correlated with the composition of the fungal communities. The short-term SBFM treatment altered microbial bacterial community compositions, which may be attributed to the phyla present (e.g., Proteobacteria and Acidobacteria), and the short-term CNFM treatment altered microbial fungal community compositions, which may be attributed to the phyla present (e.g., Ascomycota and Basidiomycota). Furthermore, soil nutrients could affect the dominant soil microbial communities, and its influence was greater on the bacterial community than on the fungal community.

scholarly journals Artificial Plantation Responses to Periodic Submergence in Massive Dam and Reservoir Riparian Zones: Changes in Soil Properties and Bacterial Community Characteristics

Biology ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 819 ◽  
Author(s):  
Jiajia Li ◽  
Lijuan Li ◽  
Muhammad Arif ◽  
Dongdong Ding ◽  
Xin Hu ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Microbial Communities ◽  
Rhizosphere Soil ◽  
Soil Microbial Communities ◽  
Chemical Properties ◽  
Riparian Zones ◽  
Woody Vegetation ◽  
Community Characteristics ◽  
Soil Microbial ◽  
Late Emergence

Plant and microbiome interactions are necessary for plant nutrient acquisition. However, relatively little is known about the responses of roots, bulk, and rhizosphere soil microbial communities in different artificial vegetation types (woody and herbaceous) in riparian areas of massive dams and reservoirs. Therefore, this study aims to assess such responses at elevations of 165–170 m a.s.l. in the riparian zones of the Three Gorges Dam Reservoir, China. The samples were collected containing the rhizosphere soil, bulk soil, and roots of herbaceous and woody vegetation at different emergence stages in 2018. Then, all the samples were analyzed to quantify the soil properties, bacterial community characteristics, and their interaction in the early and late emergence phases. In different periods, the weight of dominant soil bacteria, including Proteobacteria, Acidobacteria, Actinobacteria, Chloroflexi, and Cyanobacteria, was higher, and their composition was different in the rhizosphere, bulk soil, and endophytes. Moreover, the soil co-occurrence networks indicated that the weight of soil physical properties was higher than chemical properties in the early emergence stage. In contrast, the weight of chemical properties was relatively higher in the late emergence stage. Furthermore, the richness and diversity of the bacterial community were mainly affected by soil organic matter. This study suggests that these herbaceous and woody vegetation are suitable for planting in reservoir areas affected by hydrology and human disturbance in light of soil nutrients and soil microbial communities, respectively. Additionally, these results provide valuable information to inoculate the soil with key microbiota members by applying fertilizers, potentially improving plant health and soil production.

scholarly journals Urbanization-induced environmental changes strongly affect wetland soil bacterial community composition and diversity

2021 ◽  
Author(s):  
Xinyu Yi ◽  
Chen Ning ◽  
Shuailong Feng ◽  
Haiqiang Gao ◽  
Jianlun Zhao ◽  
...  
Keyword(s):  
Bacterial Community ◽  
Bacterial Communities ◽  
Environmental Changes ◽  
Bacterial Community Composition ◽  
Soil Microbial Communities ◽  
Environmental Drivers ◽  
Wetland Soil ◽  
Rrna Gene ◽  
Soil Microbial ◽  
Soil Bacterial

Abstract Soil microbial communities potentially serve as indicators for their responses to changes in various ecosystems at scales from a region to the globe. However, changes in wetland soil bacterial communities and how they are related to urbanization intensities remains poorly understood. Here, we collected sixty soil samples along urbanization intensity gradients from twenty wetlands. We measured a range of environmental factors and characterized bacterial communities structure using 16S rRNA gene amplicon sequencing that targeted the V4-V5 region. Our results revealed the dominant soil microbial phyla included Proteobacteria (39.3%), Acidobacteria (21.4%) and Chloroflexi (12.3%) in the wetlands, and showed a significant divergence of composition in intensive urbanization area (UI_4) than other places. A critical "threshold" exists in the soil bacterial diversity, demonstrating different patterns: a gradual increase in the areas of low-to-intermediate disturbances but a significant decrease in highly urbanized areas where metabolic functions were significantly strong. Additionally, soil pH, total phosphorus (TP), available phosphorus (AP ) and ammonia nitrogen (NH4+-N) made a significant contribution to variations in bacterial communities, explaining 49.6%, 35.1%, 26.2% and 30.7% of the total variance, respectively. pH and NH4+-N were identified as the main environmental drivers to determine bacterial community structure and diversity in the urban wetlands. Our results highlight collective changes in multiple environmental variables induced by urbanization rather than by the proportion of impervious surface area (ISA), which were potentially attributed to the spatial heterogeneity along different urbanization gradients.

Methylmercury production and degradation by soil microbial communities

2020 ◽  
Author(s):  
Yu-Rong Liu ◽  
Qiaoyun Huang
Keyword(s):  
Microbial Communities ◽  
Bacterial Community Composition ◽  
Inorganic Mercury ◽  
Soil Microbial Communities ◽  
Paddy Soils ◽  
Equation Modeling ◽  
Soil Microbial ◽  
Anaerobic Microorganisms ◽  
Water Saturated ◽  
Reducing Bacteria

<p>Rice consumption is now recognized as an important pathway of human exposure to the neurotoxin methylmercury (MeHg), particularly in countries where rice is a staple food. Although the discovery of a two-gene cluster hgcAB has linked Hg methylation to several phylogenetically diverse groups of anaerobic microorganisms converting inorganic mercury (Hg) to MeHg, the prevalence and diversity of microbial communities associated with MeHg production and degradation in paddy soils remain unclear. Both Illumina and PacBio sequencing analyses revealed that Hg methylating communities were dominated by iron-reducing bacteria (i.e., Geobacter) and methanogens, with a relatively low abundance of hgcA+ sulfate-reducing bacteria in the soil. A positive correlation was observed between the MeHg content in soil and the relative abundance of Geobacter carrying the hgcA gene. Our structure equation modeling suggested a much stronger link between bacterial community composition and %MeHg, compared to the abundance of methylating gene (hgcA) and edaphic properties. More importantly, random forest models suggested a more important role of non-Hg methylators than Hg methylators in predicting variations of soil %MeHg.</p><p>Microbial demethylation was demonstrated by significantly more degradation of MeHg in the unsterilized soils than the sterilized controls, although more degradation was observed in water-saturated soils than the unsaturated soil. 16S rRNA Illumina sequencing and metatranscriptomic analyses consistently revealed that Catenulisporaceae, Frankiaceae, Mycobacteriaceae, and Thermomonosporaceae were among the most likely microbial taxa in influencing These findings provide new insights into microbial communities associated with MeHg accumulation in paddy soils, with important implications in mitigating the net production and bioaccumulation of MeHg in rice worldwide.</p>

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