scholarly journals Extreme drought triggers transition to an alternative soil microbial state

2021 ◽  
Author(s):  
Irene Cordero ◽  
Ainara Leizeaga ◽  
Lettice C Hicks ◽  
Johannes Rousk ◽  
Richard D Bardgett

Soil microbial communities play a pivotal role in regulating ecosystem functioning but they are increasingly threatened by human-driven perturbations, including climate extremes, which are predicted to increase in frequency and intensity with climate change. It has been demonstrated that soil microbial communities are sensitive to climate extremes, such as drought, and that effects can be long-lasting. However, considerable uncertainties remain concerning the response of soil microbial communities to increases in the intensity and frequency of climate extremes, and their potential to trigger transitions to alternative, and potentially deleterious, taxonomic and functional states. Here we demonstrate that extreme, frequent drought induces a shift to an alternative soil microbial state characterised by strongly altered bacterial and fungal community structure of reduced complexity and functionality. Moreover, we found that this drought-induced alternative microbial state persisted after returning soil to its previous moisture status. However, bacterial communities were able to adapt by increasing their growth capacity, despite being of reduced diversity. Abrupt transitions to alternative states are well documented in aquatic and terrestrial plant communities in response to human-induced perturbations, including climate extremes. Our results provide experimental evidence that such transitions also occur in soil microbial communities in response to extreme drought with potentially deleterious consequences for soil health.

2020 ◽  
Vol 375 (1794) ◽  
pp. 20190112 ◽  
Author(s):  
Richard D. Bardgett ◽  
Tancredi Caruso

A major challenge for advancing our understanding of the functional role of soil microbial communities is to link changes in their structure and function under climate change. To address this challenge requires new understanding of the mechanisms that underlie the capacity of soil microbial communities to resist and recover from climate extremes. Here, we synthesize emerging understanding of the intrinsic and extrinsic factors that influence the resistance and resilience of soil microbial communities to climate extremes, with a focus on drought, and identify drivers that might trigger abrupt changes to alternative states. We highlight research challenges and propose a path for advancing our understanding of the resistance and resilience of soil microbial communities to climate extremes, and of their vulnerability to transitions to alternative states, including the use of trait-based approaches. We identify a need for new approaches to quantify resistance and resilience of soil microbial communities, and to identify thresholds for transitions to alternative states. We show how high-resolution time series coupled with gradient designs will enable detecting response patterns to interacting drivers. Finally, to account for extrinsic factors, we suggest that future studies should use environmental gradients to track soil microbial community responses to climate extremes in space and time. This article is part of the theme issue ‘Climate change and ecosystems: threats, opportunities and solutions’.


2019 ◽  
Vol 24 (1) ◽  
pp. 43
Author(s):  
Lily Ishak ◽  
Philip Hugh Brown

The role of microbial communities in maintaining soil health is mostly influenced by chemical condition of soil. Microbial communities vary in response to soil chemical factors. The contradictive results from previous findings emphasise that it is difficult to define a pattern of the influence of soil chemical factors on soil microbial diversity and activity. The aim of the study was to assess soil microbial responses to soil chemical factors in agricultural soils. Composite soil (Dermosol order) samples taken from 16 commercial crop sites in Bundaberg, Queensland, Australia, were chemically and biologically analysed. It was found that bacterial and fungal activity and diversity were significantly affected by soil EC, SOM and NO3-N content, but were not influenced by soil pH, CEC, and Ca:Mg ratio. The diversity of bacterial and fungal communities displayed a positive linear relationship with soil EC, whereas the activity and diversity of these two microbial groups and SOM displayed a significant quadratic relationship. The finding suggested that microbial community was predominantly influenced by SOM content.


2021 ◽  
Author(s):  
Jing Zhang ◽  
Peter G.L. Klinkhamer ◽  
Klaas Vrieling ◽  
T. Martijn Bezemer

Abstract Background and aimsMany plant species grow better in sterilized than in live soil. Foliar application of SA mitigates this negative effect of live soil on the growth of the plant Jacobaea vulgaris. To examine what causes the positive effect of SA application on plant growth in live soils, we analyzed the effects of SA application on the composition of active rhizosphere bacteria in the live soil. Methods We studied this over four consecutive plant cycles (generations), using mRNA sequencing of the microbial communities in the rhizosphere of J. vulgaris. ResultsOur study shows that the composition of the rhizosphere bacterial communities of J. vulgaris greatly differed among generations. Application of SA resulted in both increases and decreases in a number of active bacterial genera in the rhizosphere soil, but the genera that were affected by the treatment differed among generations. In the first generation, there were no genera that were significantly affected by the SA treatment, indicating that induction of the SA defense pathway in plants does not lead to immediate changes in the soil microbial community. 89 species out of the total 270 (32.4%) were present in all generations in all soils of SA-treated and control plants suggesting that these make up the “core” microbiome. On average in each generation, 72.9% of all genera were present in both soils. Application of SA to plants significantly up-regulated genera of Caballeronia, unclassified Cytophagaceae, Crinalium and Candidatus Thermofonsia Clade 2, and down-regulated genera of Thermomicrobiales, unclassified Rhodobacterales, Paracoccus and Flavihumibacter. While the functions of many of these bacteria are poorly understood, bacteria of the genus Caballeronia play an important role in fixing nitrogen and promoting plant growth, and hence this suggests that activation of the SA signaling pathway in J. vulgaris plants may select for bacterial genera that are beneficial to the plant. ConclusionsOverall, our study shows that aboveground activation of defenses in the plant affects soil microbial communities and, as soil microbes can greatly influence plant performance, this implies that induction of plant defenses can lead to complex above-belowground feedbacks. Further studies should examine how activation of the SA signaling pathway in the plant changes the functional genes of the rhizosphere soil bacterial community.


2019 ◽  
Vol 6 (1) ◽  
pp. 181054
Author(s):  
Zhenhua Yu ◽  
Jian Jin ◽  
Yansheng Li ◽  
Yue Yang ◽  
Yue Zhao ◽  
...  

Eroded black soils (classified as Mollisols) lead to a thinner topsoil layer, reduced organic carbon storage and declined crop productivity. Understanding the changes in soil microbial communities owing to soil erosion is of vital importance as soil microbial communities are sensitive indicators of soil condition and are essential in soil nutrient cycling. This study used the reconstructed facility with 10, 20 and 30 cm topsoil thickness under no-till soya bean–corn rotation in black soil region of Northeast China. Illumina MiSeq sequencing targeting 16S rRNA, q PCR and soil respiration measurement were performed to assess the changes in soya bean and corn rhizosphere bacterial communities, as well as their abundance and activities due to the topsoil thickness. The results showed that soil bacterial communities from both soya bean and corn were more sensitive to topsoil removal than to soil biogeochemical characteristics. Topsoil depths significantly influenced both soya bean and corn bacterial communities, while they only significantly influenced the bacterial abundance and respiration in corn. We also found that the topsoil depths significantly induced the changes in phyla and genera from both soya bean and corn rhizosphere bacterial community, which aid further understandings on how topsoil layer influences the global nutrient cycling of Mollisols by influencing the change in microbial communities.


2020 ◽  
Author(s):  
Ziyuan Zhou ◽  
Guodong Ding ◽  
Minghan Yu ◽  
Guanglei Gao ◽  
Genzhu Wang

ABSTRACTBy assessing diversity variations of bacterial communities under different rhizocompartment types (i.e., roots, rhizosphere soil, root zone soil, and inter-shrub bulk soil), we explore the structural variability of bacterial communities in different root microenvironments under desert leguminous plant shrubs. Results will enable the influence of niche differentiation of plant roots and root soil on the structural stability of bacterial communities under three desert leguminous plant shrubs to be examined. High-throughput 16S rRNA genome sequencing was used to characterize diversity and structural differences of bacterial microbes in the rhizocompartments of three xeric leguminous plants. Results from this study confirm previous findings relating to niche differentiation in rhizocompartments under related shrubs, and they demonstrate that diversity and structural composition of bacterial communities have significant hierarchical differences across four rhizocompartment types under leguminous plant shrubs. Desert leguminous plants had significant effects on the enrichment and filtration of specific bacterial microbiomes across different rhizocompartments (P<0.05). The core bacterial microbiomes causing structure and composition variability of bacterial communities across different niches of desert leguminous plants are also identified. By investigating the influence of niches on the structural variability of soil bacterial communities with the differentiation of rhizocompartments under desert leguminous plant shrubs, we provide data support for the identification of dominant bacteria and future preparation of inocula, and provide a foundation for further study of the host plants-microbial interactions.IMPORTANCEColonization by plant communities make valued contribution to sand-fixing in poor ecological desert environments, thereby reducing the effects of wind erosion in these areas. Our study revealed that specific core bacterial microbiomes in under-shrub soil microbial communities had a significant hierarchical enrichment effect among rhizocompartments, and were filtered into roots. The root endophyte microbiomes thus formed had low abundance and diversity, but their structural variability was the highest. In addition, our data also verified that the rhizocompartments of under desert leguminous plant shrubs had a significant differentiation effect for the core bacterial microbiomes enriched and filtered by host plants, and that each rhizocompartment represented a unique niche of bacterial communities. Understanding the interactions between xeric shrubs and soil microbial communities is a fundamental step for describing desert soil ecosystems, which in turn can offer a microbe-associated reference for evaluating the restoration of desert vegetation.


2019 ◽  
Vol 8 (1) ◽  
pp. 1 ◽  
Author(s):  
Sarah R. Carrino-Kyker ◽  
Kaitlin P. Coyle ◽  
Laurel A. Kluber ◽  
David J. Burke

Chronic acid deposition affects many temperate hardwood forests of the northeastern United States, reduces soil pH and phosphorus (P) availability, and can alter the structure and function of soil microbial communities. The strategies that microorganisms possess for survival in acidic, low P soil come at a carbon (C) cost. Thus, how microbial communities respond to soil acidification in forests may be influenced by plant phenological stage as C allocation belowground varies; however, this remains largely unexplored. In this study, we examined microbial communities in an ecosystem level manipulative experiment where pH and/or P availability were elevated in three separate forests in Northeastern Ohio. Tag-encoded pyrosequencing was used to examine bacterial and fungal community structure at five time points across one year corresponding to plant phenological stages. We found significant effects of pH treatment and time on fungal and bacterial communities in soil. However, we found no interaction between pH treatment and time of sampling for fungal communities and only a weak interaction between pH elevation and time for bacterial communities, suggesting that microbial community responses to soil pH are largely independent of plant phenological stage. In addition, fungal communities were structured largely by site, suggesting that fungi were responding to differences between the forests, such as plant community differences.


2021 ◽  
Vol 12 ◽  
Author(s):  
Qianxin Deng ◽  
Tong Zhang ◽  
Deti Xie ◽  
Yuheng Yang

Soil rhizosphere microorganisms play crucial roles in promoting plant nutrient absorption and maintaining soil health. However, the effects of different phosphorus (P) managements on soil microbial communities in a slope farming system are poorly understood. Here, rhizosphere microbial communities under two P fertilization levels—conventional (125 kg P2O5 ha–1, P125) and optimal (90 kg P2O5 ha–1, P90)—were compared at four growth stages of maize in a typical sloped farming system. The richness and diversity of rhizosphere bacterial communities showed significant dynamic changes throughout the growth period of maize, while different results were observed in fungal communities. However, both the P fertilization levels and the growth stages influenced the structure and composition of the maize rhizosphere microbiota. Notably, compared to P125, Pseudomonas, Conexibacter, Mycobacterium, Acidothermus, Glomeromycota, and Talaromyces were significantly enriched in the different growth stages of maize under P90, while the relative abundance of Fusarium was significantly decreased during maize harvest. Soil total nitrogen (TN) and pH are the first environmental drivers of change in bacterial and fungal community structures, respectively. The abundance of Gemmatimonadota, Proteobacteria, and Cyanobacteria showed significant correlations with soil TN, while that of Basidiomycota and Mortierellomycota was significantly related to pH. Additionally, P90 strengthened the connection between bacteria, but reduced the links between fungi at the genus level. Our work helps in understanding the role of P fertilization levels in shaping the rhizosphere microbiota and may manipulate beneficial microorganisms for better P use efficiency.


2015 ◽  
Vol 112 (35) ◽  
pp. 10967-10972 ◽  
Author(s):  
Jonathan W. Leff ◽  
Stuart E. Jones ◽  
Suzanne M. Prober ◽  
Albert Barberán ◽  
Elizabeth T. Borer ◽  
...  

Soil microorganisms are critical to ecosystem functioning and the maintenance of soil fertility. However, despite global increases in the inputs of nitrogen (N) and phosphorus (P) to ecosystems due to human activities, we lack a predictive understanding of how microbial communities respond to elevated nutrient inputs across environmental gradients. Here we used high-throughput sequencing of marker genes to elucidate the responses of soil fungal, archaeal, and bacterial communities using an N and P addition experiment replicated at 25 globally distributed grassland sites. We also sequenced metagenomes from a subset of the sites to determine how the functional attributes of bacterial communities change in response to elevated nutrients. Despite strong compositional differences across sites, microbial communities shifted in a consistent manner with N or P additions, and the magnitude of these shifts was related to the magnitude of plant community responses to nutrient inputs. Mycorrhizal fungi and methanogenic archaea decreased in relative abundance with nutrient additions, as did the relative abundances of oligotrophic bacterial taxa. The metagenomic data provided additional evidence for this shift in bacterial life history strategies because nutrient additions decreased the average genome sizes of the bacterial community members and elicited changes in the relative abundances of representative functional genes. Our results suggest that elevated N and P inputs lead to predictable shifts in the taxonomic and functional traits of soil microbial communities, including increases in the relative abundances of faster-growing, copiotrophic bacterial taxa, with these shifts likely to impact belowground ecosystems worldwide.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Thi-Minh-Dien Vuong ◽  
Jian-Yong Zeng ◽  
Xiu-Ling Man

AbstractLittle is known about the relationship between soil microbial communities and soil properties in southern boreal forests. To further our knowledge about that relationship, we compared the soil samples in southern boreal forests of the Greater Khingan Mountains—the southernmost boreal forest biome in the world. The forests can be divided into boardleaf forests dominated by birch (Betula platyphylla) or aspen (Populus davidiana) and coniferous forests dominated by larch (Larix gmelinii) or pine (Pinus sylvestris var. mongolica). Results suggested different soil microbial communities and soil properties between these southern boreal forests. Soil protease activity strongly associated with soil fungal communities in broadleaf and coniferous forests (p < 0.05), but not with soil bacterial communities (p > 0.05). Soil ammonium nitrogen and total phosphorus contents strongly associated with soil fungal and bacterial communities in broadleaf forests (p < 0.05), but not in coniferous forests (p > 0.05). Soil potassium content demonstrated strong correlations with both soil fungal and bacterial communities in broadleaf and coniferous forests (p < 0.05). These results provide evidence for different soil communities and soil properties in southern boreal forest, and further elucidate the explicit correlation between soil microbial communities and soil properties in southern boreal forests.


Author(s):  
Márton Mucsi ◽  
Gergely Krett ◽  
Tibor Szili-Kovács ◽  
János Móga ◽  
Andrea K. Borsodi

Abstract Soils play an important role in the ecosystem of karstic landscapes both as a buffer zone and as a source of acidity to belowground water. Although the microbiota of karstic soils is known to have a great effect on karstification processes, the activity and composition of these communities are largely unknown. This study gives a comparative analysis of soil microbial profiles from different parts of a doline located at Aggtelek, Hungary. The aim was to reveal the relationships between the vegetation type and genetic fingerprints and substrate utilisation (multi-SIR) profiles of the soil microbiota. Soil samples were collected in early and late springs along a transect in a doline covered with different types of vegetation. Genetic fingerprints of bacterial communities were examined by denaturing gradient gel electrophoresis (DGGE) based on the 16S rRNA gene, along with multi-SIR profiles of the microbial communities measured by the MicroResp method using 15 different carbon sources. Genetic fingerprinting indicated that vegetation cover had a strong effect on the composition of soil bacterial communities. Procrustean analysis showed only a weak connection between DGGE and multi-SIR profiles, probably due to the high functional redundancy of the communities. Seasonality had a significant effect on substrate usage, which can be an important factor to consider in future studies.


Sign in / Sign up

Export Citation Format

Share Document