A survey of invasive plants on grassland soil microbial communities and ecosystem services

Soil microbial communities are enormously diverse, with at least millions of species and trillions of genes unknown to science or poorly described. Soil microbial communities are key components of agriculture, for example, in provisioning nitrogen and protecting crops from pathogens, providing overall ecosystem services in excess of $1000bn per year. It is important to know how humans are affecting this hidden diversity. Much is known about the negative consequences of agricultural intensification on higher organisms, but almost nothing is known about how alterations to landscapes affect microbial diversity, distributions and processes. We review what is known about spatial flows of microbes and their response to land-use change, and outline nine hypotheses to advance research of microbiomes across landscapes. We hypothesize that intensified agriculture selects for certain taxa and genes, which then ‘spill over’ into adjacent unmodified areas and generate a halo of genetic differentiation around agricultural fields. Consequently, the spatial configuration and management intensity of different habitats combines with the dispersal ability of individual taxa to determine the extent of spillover, which can impact the functioning of adjacent unmodified habitats. When landscapes are heterogeneous and dispersal rates are high, this will select for large genomes that allow exploitation of multiple habitats, a process that may be accelerated through horizontal gene transfer. Continued expansion of agriculture will increase genotypic similarity, making microbial community functioning increasingly variable in human-dominated landscapes, potentially also impacting the consistent provisioning of ecosystem services. While the resulting economic costs have not been calculated, it is clear that dispersal dynamics of microbes should be taken into consideration to ensure that ecosystem functioning and services are maintained in agri-ecosystem mosaics.

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An invasive plant rapidly increased the similarity of soil fungal pathogen communities

Annals of Botany ◽

10.1093/aob/mcaa191 ◽

2020 ◽

Author(s):

Meiling Wang ◽

Xuefei Tang ◽

Xiaoqiu Sun ◽

Bingbing Jia ◽

Hao Xu ◽

...

Keyword(s):

Microbial Communities ◽

Invasive Plants ◽

Fungal Pathogen ◽

High Throughput Sequencing ◽

Invasive Plant ◽

Soil Microbial Communities ◽

Plant Invasions ◽

Alternanthera Philoxeroides ◽

Native Plant ◽

Soil Microbial

Abstract Background and Aims Plant invasions can change soil microbial communities and affect subsequent invasions directly or indirectly via foliar herbivory. It has been proposed that invaders promote uniform biotic communities that displace diverse, spatially variable communities (the biotic homogenization hypothesis), but this has not been experimentally tested for soil microbial communities, so the underlying mechanisms and dynamics are unclear. Here, we compared density-dependent impacts of the invasive plant Alternanthera philoxeroides and its native congener A. sessilis on soil fungal communities, and their feedback effects on plants and a foliar beetle. Methods We conducted a plant–soil feedback (PSF) experiment and a laboratory bioassay to examine PSFs associated with the native and invasive plants and a beetle feeding on them. We also characterized the soil fungal community using high-throughput sequencing. Key Results We found locally differentiated soil fungal pathogen assemblages associated with high densities of the native plant A. sessilis but little variation in those associated with the invasive congener A. philoxeroides, regardless of plant density. In contrast, arbuscular mycorrhizal fungal assemblages associated with high densities of the invasive plant were more variable. Soil biota decreased plant shoot mass but their effect was weak for the invasive plant growing in native plant-conditioned soils. PSFs increased the larval biomass of a beetle reared on leaves of the native plant only. Moreover, PSFs on plant shoot and root mass and beetle mass were predicted by different pathogen taxa in a plant species-specific manner. Conclusion Our results suggest that plant invasions can rapidly increase the similarity of soil pathogen assemblages even at low plant densities, leading to taxonomically and functionally homogeneous soil communities that may limit negative soil effects on invasive plants.

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Plant functional trait shifts explain concurrent changes in the structure and function of grassland soil microbial communities

Journal of Ecology ◽

10.1111/1365-2745.13182 ◽

2019 ◽

Vol 107 (5) ◽

pp. 2197-2210 ◽

Cited By ~ 15

Author(s):

Runa S. Boeddinghaus ◽

Sven Marhan ◽

Doreen Berner ◽

Steffen Boch ◽

Markus Fischer ◽

...

Keyword(s):

Microbial Communities ◽

Soil Microbial Communities ◽

Functional Trait ◽

Structure And Function ◽

Grassland Soil ◽

Soil Microbial ◽

Plant Functional Trait ◽

And Function

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Effects of Mikania Sesquiterpene Lactones on Soil Microbes

10.21203/rs.3.rs-225278/v1 ◽

2021 ◽

Author(s):

Hanxia Yu ◽

Johannes J. Le Roux ◽

Mengxin Zhao ◽

Weihua Li

Keyword(s):

Microbial Communities ◽

Functional Groups ◽

Invasive Plants ◽

Soil Microbes ◽

Sulfur Metabolism ◽

Sesquiterpene Lactones ◽

Soil Microbial Communities ◽

Soil Microbial Activity ◽

Invasion Success ◽

Soil Microbial

Abstract Background and aims Allelopathy is frequently invoked as being important for successful invasion by non-native plants. Yet, the effects of specific phytochemicals of invasive plants on soil microbes remain unexplored. Methods Here we used manipulative experiments and next generation sequencing (NGS) approaches to investigate how the sesquiterpene lactones (STLs) of invasive Mikania micrantha influence soil microbial communities and nutrients.Results We found Mikania STLs to significantly increase the regulation of soil microbial activity (i.e. increased CO2 concentrations). Using the specific STL, dihydromikanolide, we found available soil nutrients to increase in the presence of this phytochemical and that bacterial richness increased while fungal richness decreased. The presence of dihydromikanolide also increased the abundance of beneficial soil bacteria and fungi associated with nutrient cycling and supply, while simultaneously lowering pathogen abundance. Clustering analysis found bacterial functional groups, such as those involved in carbon, nitrogen, phosphorus, and sulfur metabolism, to be similar in experimentally-treated dihydromikanolide soils and Mikania-invaded soils collected from the field, but significantly higher than those in uninvaded soils. This suggests that M. micrantha can enhance certain bacterial functional groups via its phytochemicals. Soil fungi, on the other hand, appeared to be less sensitive to dihydromikanolide than bacteria. Conclusions We conclude Mikania STLs, and in particular dihydromikanolide, may be key factors in determining soil microbial structure and function and may contribute to the invasion success of the species. Our findings provided a new perspective for understanding the effects of invasive plants on soil microbial communities via their impacts through phytochemicals.

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Functional shifts of soil microbial communities associated with Alliaria petiolata invasion

10.1101/2020.08.13.248849 ◽

2020 ◽

Author(s):

Katherine Duchesneau ◽

Anneke Golemiec ◽

Robert I. Colautti ◽

Pedro M. Antunes

Keyword(s):

Microbial Communities ◽

Invasive Plants ◽

Mycorrhizal Fungi ◽

Soil Microbial Communities ◽

Arbuscular Mycorrhizal ◽

Alliaria Petiolata ◽

Native Plant ◽

Soil Microbial Diversity ◽

Soil Microbial ◽

Enemy Hypothesis

AbstractSoil feedback is thought to be an important contributor to the success of invasive plants. Despite evidence that invasive plants change soil microbial diversity, the functional roles of microbes impacted by invasion are still unclear. This knowledge is a critical component of our understanding of ecological mechanisms of plant invasion. Mounting evidence suggests Alliaria petiolata can suppress arbuscular mycorrhizal fungi (AMF) to disrupt native plant communities in controlled laboratory and greenhouse experiments, though it is less clear if allelochemicals persist under natural field conditions. Alternatively, invasive plants may accumulate pathogens that are more harmful to competitors as predicted by the Enemy of my Enemy Hypothesis (EEH). We examined changes in functional groups of soil bacteria and fungi associated with ten naturally occurring populations of A. petiolata using amplicon sequences (16S and ITS rRNA). To relate soil microbial communities to impacts on co-occurring plants, we measured root infections and AMF colonization. We found no changes in the diversity and abundance of AMF in plants co-occurring with A. petiolata, suggesting that mycorrhizal suppression in the field may not be as critical to the invasion of A. petiolata as implied by more controlled experiments. Instead, we found changes in pathogen community composition and marginal evidence of increase in root lesions of plants growing with A. petiolata, lending support to the EEH. In addition to these impacts on plant health, changes in ectomycorrhiza, and other nutrient cycling microbes may be important forces underlying the invasion of A. petiolata and its impact on ecosystem function.

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