Soil Ecology
535 views | +0 today
Follow
Your new post is loading...
Your new post is loading...
Rescooped by Fabiane Vezzani from Plant roots and rhizosphere
Scoop.it!

Lost in diversity: the interactions between soil‐borne fungi, biodiversity and plant productivity - Mommer - 2018 - New Phytologist -

Lost in diversity: the interactions between soil‐borne fungi, biodiversity and plant productivity - Mommer - 2018 - New Phytologist - | Soil Ecology | Scoop.it
There is consensus that plant species richness enhances plant productivity within natural grasslands, but the underlying drivers remain debated. Recently, differential accumulation of soil‐borne fungal pathogens across the plant diversity gradient has been proposed as a cause of this pattern. However, the below‐ground environment has generally been treated as a ‘black box’ in biodiversity experiments, leaving these fungi unidentified.
Using next generation sequencing and pathogenicity assays, we analysed the community composition of root‐associated fungi from a biodiversity experiment to examine if evidence exists for host specificity and negative density dependence in the interplay between soil‐borne fungi, plant diversity and productivity.
Plant species were colonised by distinct (pathogenic) fungal communities and isolated fungal species showed negative, species‐specific effects on plant growth. Moreover, 57% of the pathogenic fungal operational taxonomic units (OTUs) recorded in plant monocultures were not detected in eight plant species plots, suggesting a loss of pathogenic OTUs with plant diversity.
Our work provides strong evidence for host specificity and negative density‐dependent effects of root‐associated fungi on plant species in grasslands. Our work substantiates the hypothesis that fungal root pathogens are an important driver of biodiversity‐ecosystem functioning relationships.

Via Christophe Jacquet
more...
No comment yet.
Scooped by Fabiane Vezzani
Scoop.it!

Feed Your Friends: Do Plant Exudates Shape the Root Microbiome?

Feed Your Friends: Do Plant Exudates Shape the Root Microbiome? | Soil Ecology | Scoop.it
Plant health in natural environments depends on interactions with complex and dynamic communities comprising macro- and microorganisms. While many studies have provided insights into the composition of rhizosphere microbiomes (rhizobiomes), little is known about whether plants shape their rhizobiomes. Here, we discuss physiological factors of plants that may govern plant–microbe interactions, focusing on root physiology and the role of root exudates. Given that only a few plant transport proteins are known to be involved in root metabolite export, we suggest novel families putatively involved in this process. Finally, building off of the features discussed in this review, and in analogy to well-known symbioses, we elaborate on a possible sequence of events governing rhizobiome assembly.
more...
No comment yet.
Scooped by Fabiane Vezzani
Scoop.it!

Quantification of root water uptake in soil using X‐ray computed tomography and image‐based modelling

Quantification of root water uptake in soil using X‐ray computed tomography and image‐based modelling | Soil Ecology | Scoop.it
Spatially averaged models of root–soil interactions are often used to calculate plant water uptake. Using a combination of X-ray computed tomography (CT) and image-based modelling, we tested the accuracy of this spatial averaging by directly calculating plant water uptake for young wheat plants in two soil types. The root system was imaged using X-ray CT at 2, 4, 6, 8 and 12 d after transplanting. The roots were segmented using semi-automated root tracking for speed and reproducibility. The segmented geometries were converted to a mesh suitable for the numerical solution of Richards' equation. Richards' equation was parameterized using existing pore scale studies of soil hydraulic properties in the rhizosphere of wheat plants. Image-based modelling allows the spatial distribution of water around the root to be visualized and the fluxes into the root to be calculated. By comparing the results obtained through image-based modelling to spatially averaged models, the impact of root architecture and geometry in water uptake was quantified. We observed that the spatially averaged models performed well in comparison to the image-based models with <2% difference in uptake. However, the spatial averaging loses important information regarding the spatial distribution of water near the root system.
more...
No comment yet.
Rescooped by Fabiane Vezzani from Plant-Microbe Symbiosis
Scoop.it!

Chemical signaling involved in plant–microbe interactions

Chemical signaling involved in plant–microbe interactions | Soil Ecology | Scoop.it
Microorganisms are found everywhere, and they are closely associated with plants. Because the establishment of any plant–microbe association involves chemical communication, understanding crosstalk processes is fundamental to defining the type of relationship. Although several metabolites from plants and microbes have been fully characterized, their roles in the chemical interplay between these partners are not well understood in most cases, and they require further investigation. In this review, we describe different plant–microbe associations from colonization to microbial establishment processes in plants along with future prospects, including agricultural benefits.


Via Jean-Michel Ané
more...
No comment yet.
Rescooped by Fabiane Vezzani from MycorWeb Plant-Microbe Interactions
Scoop.it!

Ecosystem responses to elevated CO2 governed by plant–soil interactions and the cost of nitrogen acquisition

Ecosystem responses to elevated CO2 governed by plant–soil interactions and the cost of nitrogen acquisition | Soil Ecology | Scoop.it
Land ecosystems sequester on average about a quarter of anthropogenic CO2 emissions. It has been proposed that nitrogen (N) availability will exert an increasingly limiting effect on plants’ ability to store additional carbon (C) under rising CO2, but these mechanisms are not well understood. Here, we review findings from elevated CO2 experiments using a plant economics framework, highlighting how ecosystem responses to elevated CO2 may depend on the costs and benefits of plant interactions with mycorrhizal fungi and symbiotic N-fixing microbes. We found that N-acquisition efficiency is positively correlated with leaf-level photosynthetic capacity and plant growth, and negatively with soil C storage. Plants that associate with ectomycorrhizal fungi and N-fixers may acquire N at a lower cost than plants associated with arbuscular mycorrhizal fungi. However, the additional growth in ectomycorrhizal plants is partly offset by decreases in soil C pools via priming. Collectively, our results indicate that predictive models aimed at quantifying C cycle feedbacks to global change may be improved by treating N as a resource that can be acquired by plants in exchange for energy, with different costs depending on plant interactions with microbial symbionts.

Via Francis Martin
more...
No comment yet.
Rescooped by Fabiane Vezzani from Plant-Microbe Symbiosis
Scoop.it!

Ecosystem responses to elevated CO2 governed by plant–soil interactions and the cost of nitrogen acquisition

Land ecosystems sequester on average about a quarter of anthropogenic CO2 emissions. It has been proposed that nitrogen (N) availability will exert an increasingly limiting effect on plants’ ability to store additional carbon (C) under rising CO2, but these mechanisms are not well understood. Here, we review findings from elevated CO2 experiments using a plant economics framework, highlighting how ecosystem responses to elevated CO2 may depend on the costs and benefits of plant interactions with mycorrhizal fungi and symbiotic N-fixing microbes. We found that N-acquisition efficiency is positively correlated with leaf-level photosynthetic capacity and plant growth, and negatively with soil C storage. Plants that associate with ectomycorrhizal fungi and N-fixers may acquire N at a lower cost than plants associated with arbuscular mycorrhizal fungi. However, the additional growth in ectomycorrhizal plants is partly offset by decreases in soil C pools via priming. Collectively, our results indicate that predictive models aimed at quantifying C cycle feedbacks to global change may be improved by treating N as a resource that can be acquired by plants in exchange for energy, with different costs depending on plant interactions with microbial symbionts.

Via Jean-Michel Ané
more...
No comment yet.
Rescooped by Fabiane Vezzani from Plant-Microbe Symbiosis
Scoop.it!

Food for thought: how nutrients regulate root system architecture

Food for thought: how nutrients regulate root system architecture | Soil Ecology | Scoop.it
The spatial arrangement of the plant root system (root system architecture, RSA) is very sensitive to edaphic and endogenous signals that report on the nutrient status of soil and plant. Signalling pathways underpinning RSA responses to individual nutrients, particularly nitrate and phosphate, have been unravelled. Researchers have now started to investigate interactive effects between two or more nutrients on RSA. Several proteins enabling crosstalk between signalling pathways have recently been identified. RSA is potentially an important trait for sustainable and/or marginal agriculture. It is generally assumed that RSA responses are adaptive and optimise nutrient uptake in a given environment, but hard evidence for this paradigm is still sparse. Here we summarize recent advances made in these areas of research.


Via Jean-Michel Ané
more...
No comment yet.
Scooped by Fabiane Vezzani
Scoop.it!

Food for thought: how nutrients regulate root system architecture

Food for thought: how nutrients regulate root system architecture | Soil Ecology | Scoop.it

Highlights

• Root system architecture is a precise readout of nutrient signalling.
• RSA is regulated by transcriptional, translational, redox and cell-wall processes.
• Peptides act as local and systemic signals in N and P signalling.
• Crosstalk of nutrient signalling pathways underpins interactive effects.


RSA correlates with nutrient use efficiency and yield in crop genotypes.

The spatial arrangement of the plant root system (root system architecture, RSA) is very sensitive to edaphic and endogenous signals that report on the nutrient status of soil and plant. Signalling pathways underpinning RSA responses to individual nutrients, particularly nitrate and phosphate, have been unravelled. Researchers have now started to investigate interactive effects between two or more nutrients on RSA. Several proteins enabling crosstalk between signalling pathways have recently been identified. RSA is potentially an important trait for sustainable and/or marginal agriculture. It is generally assumed that RSA responses are adaptive and optimise nutrient uptake in a given environment, but hard evidence for this paradigm is still sparse. Here we summarize recent advances made in these areas of research.

more...
No comment yet.
Scooped by Fabiane Vezzani
Scoop.it!

How Plant Root Exudates Shape the Nitrogen Cycle

How Plant Root Exudates Shape the Nitrogen Cycle | Soil Ecology | Scoop.it
Although the global nitrogen (N) cycle is largely driven by soil microbes, plant root exudates can profoundly modify soil microbial communities and influence their N transformations. A detailed understanding is now beginning to emerge regarding the control that root exudates exert over two major soil N processes – nitrification and N2 fixation. We discuss recent breakthroughs in this area, including the identification of root exudates as nitrification inhibitors and as signaling compounds facilitating N-acquisition symbioses. We indicate gaps in current knowledge, including questions of how root exudates affect newly discovered microbial players and N-cycle components. A better understanding of these processes is urgent given the widespread inefficiencies in agricultural N use and their links to N pollution and climate change.
more...
No comment yet.
Scooped by Fabiane Vezzani
Scoop.it!

Building a better foundation: improving root‐trait measurements to understand and model plant and ecosystem processes

Building a better foundation: improving root‐trait measurements to understand and model plant and ecosystem processes | Soil Ecology | Scoop.it
Trait-based approaches provide a useful framework to investigate plant strategies for resource acquisition, growth, and competition, as well as plant impacts on ecosystem processes. Despite significant progress capturing trait variation within and among stems and leaves, identification of trait syndromes within fine-root systems and between fine roots and other plant organs is limited. Here we discuss three underappreciated areas where focused measurements of fine-root traits can make significant contributions to ecosystem science. These include assessment of spatiotemporal variation in fine-root traits, integration of mycorrhizal fungi into fine-root-trait frameworks, and the need for improved scaling of traits measured on individual roots to ecosystem-level processes. Progress in each of these areas is providing opportunities to revisit how below-ground processes are represented in terrestrial biosphere models. Targeted measurements of fine-root traits with clear linkages to ecosystem processes and plant responses to environmental change are strongly needed to reduce empirical and model uncertainties. Further identifying how and when suites of root and whole-plant traits are coordinated or decoupled will ultimately provide a powerful tool for modeling plant form and function at local and global scales.
more...
No comment yet.
Rescooped by Fabiane Vezzani from Plant pathogenic fungi
Scoop.it!

Ancestral alliances: Plant mutualistic symbioses with fungi and bacteria

Ancestral alliances: Plant mutualistic symbioses with fungi and bacteria | Soil Ecology | Scoop.it
BACKGROUND
Among the extensive cortège of plant-associated microorganisms (the so-called plant microbiota), mutualistic fungal and bacterial symbionts are striking examples of soil microorganisms that have successfully coevolved with their hosts since plants adapted to terrestrial ecosystems. They promote plant growth by facilitating the acquisition of scarce nutrients. In these associations, plant root colonization requires complex molecular cross-talk between symbiotic partners to activate a variety of host developmental pathways and specialized symbiotic tissues and organs. Despite the evolutionary distances that separate mycorrhizal and nitrogen-fixing symbioses, recent research has identified certain highly conserved features associated with early stages of root colonization. We focus on recent and emerging areas of investigation concerning these major mutualistic symbioses and discuss some of the molecular pathways and cellular mechanisms involved in their evolution and development.
ADVANCES
Phylogenomic analyses and divergence time estimates based on symbiotic plant fossils are shedding light on the evolution of mutualistic symbioses. The earliest land plants [~407 million years ago (Ma)] were associated with fungi producing mycorrhiza-like intracellular structures similar to extant symbioses involving Glomeromycotina and Mucoromycotina. Arbuscular mycorrhizal endosymbioses then diversified by the Late Carboniferous. Pinaceae species from the Late Jurassic and Early Cretaceous (~180 Ma) formed the first ectomycorrhizal associations involving Dikarya. More recently, certain angiosperms evolved a “predisposition” for the evolution of nitrogen-fixing root nodule symbioses (~100 Ma) with bacteria.

A conserved core module of the “common symbiotic signaling pathway” (CSSP) is shared by all host plants that establish endosymbioses, including arbuscular mycorrhizal, rhizobial, and actinorhizal associations. This striking conservation among widely divergent host species underlines the shared evolutionary origin for this ancient symbiotic signaling pathway. Furthermore, chitin-based signaling molecules secreted by both arbuscular mycorrhizal fungi and rhizobia activate the host CSSP after perception by related receptor-like kinases. Downstream signal transduction pathways then lead to the apoplastic intracellular infection modes that characterize the majority of these associations and, finally, to the coordinated development of sophisticated bidirectional symbiotic interfaces found in both arbuscules and nitrogen-fixing nodules. A common feature of all these mutualistic associations is phytohormone-associated modifications of root development, which lead to an increase in potential colonization sites as well as major structural and functional changes to the root during the establishment of symbiotic tissues.
OUTLOOK
Although we are at last beginning to understand how mutualistic microorganisms communicate with plants, how associated root developmental pathways are modulated, and how plant immune responses are successfully circumvented, many important questions remain. For example, little is currently known about more primitive modes of intercellular apoplastic colonization, whether for ectomycorrhizal fungi or for certain nitrogen-fixing symbioses. Neither do we know whether the CSSP has a key role in ectomycorrhizal associations, nor how host plants distinguish between structurally similar chitin-based “symbiotic” and “pathogenic” microbial signals. Answering these questions should contribute to our understanding of the underlying mechanisms that govern the relationships between plants and their entire microbiota. On a broader level, improved understanding of how environmental and genetic cues, together with plant metabolism, modulate microbial colonization will be crucial for the future exploitation of the microbiota for the benefit of sustainable plant growth.

Via Steve Marek
more...
No comment yet.
Rescooped by Fabiane Vezzani from MycorWeb Plant-Microbe Interactions
Scoop.it!

Leaf bacterial diversity mediates plant diversity and ecosystem function relationships : Nature

Leaf bacterial diversity mediates plant diversity and ecosystem function relationships : Nature | Soil Ecology | Scoop.it
Research on biodiversity and ecosystem functioning has demonstrated links between plant diversity and ecosystem functions such as productivity1, 2. At other trophic levels, the plant microbiome has been shown to influence host plant fitness and function3, 4, and host-associated microbes have been proposed to influence ecosystem function through their role in defining the extended phenotype of host organisms5, 6 However, the importance of the plant microbiome for ecosystem function has not been quantified in the context of the known importance of plant diversity and traits. Here, using a tree biodiversity–ecosystem functioning experiment, we provide strong support for the hypothesis that leaf bacterial diversity is positively linked to ecosystem productivity, even after accounting for the role of plant diversity. Our results also show that host species identity, functional identity and functional diversity are the main determinants of leaf bacterial community structure and diversity. Our study provides evidence of a positive correlation between plant-associated microbial diversity and terrestrial ecosystem productivity, and a new mechanism by which models of biodiversity–ecosystem functioning relationships can be improved.

Via Francis Martin
more...
No comment yet.
Scooped by Fabiane Vezzani
Scoop.it!

Soil Biodiversity Effects from Field to Fork

Soil Biodiversity Effects from Field to Fork | Soil Ecology | Scoop.it
Our knowledge of soil biodiversity in agriculture in general is currently increasing rapidly. However, almost all studies have stopped with the quantification of soil biodiversity effects on crops at harvest time, ignoring subsequent processes along the agrifood chain until food arrives on our plates. Here we develop a conceptual framework for the study of such postharvest effects. We present the main mechanisms (direct and indirect) via which soil biodiversity can influence crop quality aspects and give examples of how effects at harvest time may become attenuated through postharvest operations and how biodiversity may also affect some of these operations (i.e., storage) themselves. Future research with a broader focus has the potential to unveil how soil biodiversity may benefit from what ends up on our forks.
more...
No comment yet.
Rescooped by Fabiane Vezzani from The Plant Microbiome
Scoop.it!

Cropping practices manipulate abundance patterns of root and soil microbiome members paving the way to smart farming

Cropping practices manipulate abundance patterns of root and soil microbiome members paving the way to smart farming | Soil Ecology | Scoop.it
Harnessing beneficial microbes presents a promising strategy to optimize plant growth and agricultural sustainability. Little is known to which extent and how specifically soil and plant microbiomes can be manipulated through different cropping practices. Here, we investigated soil and wheat root microbial communities in a cropping system experiment consisting of conventional and organic managements, both with different tillage intensities. While microbial richness was marginally affected, we found pronounced cropping effects on community composition, which were specific for the respective microbiomes. Soil bacterial communities were primarily structured by tillage, whereas soil fungal communities responded mainly to management type with additional effects by tillage. In roots, management type was also the driving factor for bacteria but not for fungi, which were generally determined by changes in tillage intensity. To quantify an “effect size” for microbiota manipulation, we found that about 10% of variation in microbial communities was explained by the tested cropping practices. Cropping sensitive microbes were taxonomically diverse, and they responded in guilds of taxa to the specific practices. These microbes also included frequent community members or members co-occurring with many other microbes in the community, suggesting that cropping practices may allow manipulation of influential community members. Understanding the abundance patterns of cropping sensitive microbes presents the basis towards developing microbiota management strategies for smart farming. For future targeted microbiota management—e.g., to foster certain microbes with specific agricultural practices—a next step will be to identify the functional traits of the cropping sensitive microbes.

Via Stéphane Hacquard
more...
Jonathan Lapleau's curator insight, January 20, 5:50 AM
Combining cropping practices and soil microbes management = smart farming. We are at the beginning of big changes in agriculture.
Rescooped by Fabiane Vezzani from Plant-Microbe Symbiosis
Scoop.it!

Exploiting rhizosphere microbial cooperation for developing sustainable agriculture strategies

The rhizosphere hosts a considerable microbial community. Among that community, bacteria called plant growth-promoting rhizobacteria (PGPR) can promote plant growth and defense against diseases using diverse distinct plant-beneficial functions. Crop inoculation with PGPR could allow to reduce the use of pesticides and fertilizers in agrosystems. However, microbial crop protection and growth stimulation would be more efficient if cooperation between rhizosphere bacterial populations was taken into account when developing biocontrol agents and biostimulants. Rhizospheric bacteria live in multi-species biofilms formed all along the root surface or sometimes inside the plants (i.e., endophyte). PGPR cooperate with their host plants and also with other microbial populations inside biofilms. These interactions are mediated by a large diversity of microbial metabolites and physical signals that trigger cell–cell communication and appropriate responses. A better understanding of bacterial behavior and microbial cooperation in the rhizosphere could allow for a more successful use of bacteria in sustainable agriculture. This review presents an ecological view of microbial cooperation in agrosystems and lays the emphasis on the main microbial metabolites involved in microbial cooperation, plant health protection, and plant growth stimulation. Eco-friendly inoculant consortia that will foster microbe–microbe and microbe–plant cooperation can be developed to promote crop growth and restore biodiversity and functions lost in agrosystems.


Via Jean-Michel Ané
more...
No comment yet.
Rescooped by Fabiane Vezzani from Plant-Microbe Symbiosis
Scoop.it!

Previous crop and rotation history effects on maize seedling health and associated rhizosphere microbiome

Previous crop and rotation history effects on maize seedling health and associated rhizosphere microbiome | Soil Ecology | Scoop.it
To evaluate crop rotation effects on maize seedling performance and its associated microbiome, maize plants were grown in the greenhouse in soils preceded by either maize, pea, soybean or sunflower. Soils originated from a replicated field experiment evaluating different four-year rotation combinations. In the greenhouse, a stressor was introduced by soil infestation with western corn rootworm (WCR) or Fusarium graminearum. Under non-infested conditions, maize seedlings grown in soils preceded by sunflower or pea had greater vigor. Stress with WCR or F. graminearum resulted in significant root damage. WCR root damage was equivalent for seedlings regardless of soil provenance; whereas F. graminearum root damage was significantly lower in maize grown in soils preceded by sunflower. Infestation with WCR affected specific microbial taxa (Acinetobacter, Smaragdicoccus, Aeromicrobium, Actinomucor). Similarly, F. graminearum affected fungal endophytes including Trichoderma and Endogone. In contrast to the biological stressors, rotation sequence had a greater effect on rhizosphere microbiome composition, with larger effects observed for fungi compared to bacteria. In particular, relative abundance of Glomeromycota was significantly higher in soils preceded by sunflower or maize. Defining the microbial players involved in crop rotational effects in maize will promote selection and adoption of favorable crop rotation sequences.


Via Jean-Michel Ané
more...
No comment yet.
Scooped by Fabiane Vezzani
Scoop.it!

Disentangling above‐ and below‐ground facilitation drivers in arid environments: the role of soil microorganisms, soil properties and microhabitat

Disentangling above‐ and below‐ground facilitation drivers in arid environments: the role of soil microorganisms, soil properties and microhabitat | Soil Ecology | Scoop.it
Nurse plants promote establishment of other plant species by buffering climate extremes and improving soil properties. Soil biota plays an important role, but an analysis to disentangle the effects of soil microorganisms, soil properties and microclimate on facilitation is lacking.
In three microhabitats (gaps, small and large Retama shrubs), we placed six microcosms with sterilized soil, two per soil origin (i.e. from each microhabitat). One in every pair received an alive, and the other a sterile, inoculum from its own soil. Seeds of annual plants were sown into the microcosms. Germination, survival and biomass were monitored. Soil bacterial communities were characterized by pyrosequencing.
Germination in living Retama inoculum was nearly double that of germination in sterile inoculum. Germination was greater under Retama canopies than in gaps. Biomass was up to three times higher in nurse than in gap soils. Soil microorganisms, soil properties and microclimate showed a range of positive to negative effects on understory plants depending on species identity and life stage.
Nurse soil microorganisms promoted germination, but the effect was smaller than the positive effects of soil properties and microclimate under nurses. Nurse below-ground environment (soil properties and microorganisms) promoted plant growth and survival more than nurse microhabitat.
more...
No comment yet.
Rescooped by Fabiane Vezzani from MycorWeb Plant-Microbe Interactions
Scoop.it!

A communal catalogue reveals Earth’s multiscale microbial diversity : Nature

A communal catalogue reveals Earth’s multiscale microbial diversity : Nature | Soil Ecology | Scoop.it
Our growing awareness of the microbial world’s importance and diversity contrasts starkly with our limited understanding of its fundamental structure. Despite recent advances in DNA sequencing, a lack of standardized protocols and common analytical frameworks impedes comparisons among studies, hindering the development of global inferences about microbial life on Earth. Here we present a meta-analysis of microbial community samples collected by hundreds of researchers for the Earth Microbiome Project. Coordinated protocols and new analytical methods, particularly the use of exact sequences instead of clustered operational taxonomic units, enable bacterial and archaeal ribosomal RNA gene sequences to be followed across multiple studies and allow us to explore patterns of diversity at an unprecedented scale. The result is both a reference database giving global context to DNA sequence data and a framework for incorporating data from future studies, fostering increasingly complete characterization of Earth’s microbial diversity.

Via Francis Martin
more...
No comment yet.
Scooped by Fabiane Vezzani
Scoop.it!

Ex situ conservation of plant diversity in the world’s botanic gardens

Ex situ conservation of plant diversity in the world’s botanic gardens | Soil Ecology | Scoop.it

Botanic gardens conserve plant diversity ex situ and can prevent extinction through integrated conservation action. Here we quantify how that diversity is conserved in ex situ collections across the world’s botanic gardens. We reveal that botanic gardens manage at least 105,634 species, equating to 30% of all plant species diversity, and conserve over 41% of known threatened species. However, we also reveal that botanic gardens are disproportionately temperate, with 93% of species held in the Northern Hemisphere. Consequently, an estimated 76% of species absent from living collections are tropical in origin. Furthermore, phylogenetic bias ensures that over 50% of vascular genera, but barely 5% of non-vascular genera, are conserved ex situ. While botanic gardens are discernibly responding to the threat of species extinction, just 10% of network capacity is devoted to threatened species. We conclude that botanic gardens play a fundamental role in plant conservation, but identify actions to enhance future conservation of biodiversity.

more...
No comment yet.
Scooped by Fabiane Vezzani
Scoop.it!

Role of root exudates in metal acquisition and tolerance

Role of root exudates in metal acquisition and tolerance | Soil Ecology | Scoop.it

Highlights

• Strategy I plants secrete riboflavins or phenolics to facilitate Fe acquisition.
• Strategy II plants secrete phytosiderophores to acquire Fe.
• Exudation of organic acids is important for heavy metal detoxification.

Plants acquire mineral nutrients mostly through the rhizosphere; they secrete a large number of metabolites into the rhizosphere to regulate nutrient availability and to detoxify undesirable metal pollutants in soils. The secreted metabolites are inorganic ions, gaseous molecules, and mainly carbon-based compounds. This review focuses on the mechanisms and regulation of low-molecular-weight organic-compound exudation in terms of metal acquisition. We summarize findings on riboflavin/phenolic-facilitated and phytosiderophore-facilitated iron acquisition and discuss recent studies of the functions and secretion mechanisms of low-molecular-weight organic acids in heavy-metal detoxification.

more...
No comment yet.
Rescooped by Fabiane Vezzani from Soil Ecology
Scoop.it!

A global Fine‐Root Ecology Database to address below‐ground challenges in plant ecology

A global Fine‐Root Ecology Database to address below‐ground challenges in plant ecology | Soil Ecology | Scoop.it
Variation and tradeoffs within and among plant traits are increasingly being harnessed by empiricists and modelers to understand and predict ecosystem processes under changing environmental conditions. While fine roots play an important role in ecosystem functioning, fine-root traits are underrepresented in global trait databases. This has hindered efforts to analyze fine-root trait variation and link it with plant function and environmental conditions at a global scale. This Viewpoint addresses the need for a centralized fine-root trait database, and introduces the Fine-Root Ecology Database (FRED, http://roots.ornl.gov) which so far includes > 70 000 observations encompassing a broad range of root traits and also includes associated environmental data. FRED represents a critical step toward improving our understanding of below-ground plant ecology. For example, FRED facilitates the quantification of variation in fine-root traits across root orders, species, biomes, and environmental gradients while also providing a platform for assessments of covariation among root, leaf, and wood traits, the role of fine roots in ecosystem functioning, and the representation of fine roots in terrestrial biosphere models. Continued input of observations into FRED to fill gaps in trait coverage will improve our understanding of changes in fine-root traits across space and time.

Via Jean-Michel Ané, Fabiane Vezzani
more...
No comment yet.
Rescooped by Fabiane Vezzani from Plant-Microbe Symbiosis
Scoop.it!

A global Fine‐Root Ecology Database to address below‐ground challenges in plant ecology

A global Fine‐Root Ecology Database to address below‐ground challenges in plant ecology | Soil Ecology | Scoop.it
Variation and tradeoffs within and among plant traits are increasingly being harnessed by empiricists and modelers to understand and predict ecosystem processes under changing environmental conditions. While fine roots play an important role in ecosystem functioning, fine-root traits are underrepresented in global trait databases. This has hindered efforts to analyze fine-root trait variation and link it with plant function and environmental conditions at a global scale. This Viewpoint addresses the need for a centralized fine-root trait database, and introduces the Fine-Root Ecology Database (FRED, http://roots.ornl.gov) which so far includes > 70 000 observations encompassing a broad range of root traits and also includes associated environmental data. FRED represents a critical step toward improving our understanding of below-ground plant ecology. For example, FRED facilitates the quantification of variation in fine-root traits across root orders, species, biomes, and environmental gradients while also providing a platform for assessments of covariation among root, leaf, and wood traits, the role of fine roots in ecosystem functioning, and the representation of fine roots in terrestrial biosphere models. Continued input of observations into FRED to fill gaps in trait coverage will improve our understanding of changes in fine-root traits across space and time.

Via Jean-Michel Ané
more...
No comment yet.
Scooped by Fabiane Vezzani
Scoop.it!

Lux bacterial biosensors for in vivo spatiotemporal mapping of root secretion

Lux bacterial biosensors for in vivo spatiotemporal mapping of root secretion | Soil Ecology | Scoop.it
Plants engineer the rhizosphere to their advantage by secreting various nutrients and secondary metabolites. Coupling transcriptomic and metabolomic analysis of the Pisum sativum rhizosphere, a suite of bioreporters has been developed in Rhizobium leguminosarum bv. viciae 3841, and these detect metabolites secreted by roots in space and time. Fourteen bacterial lux-fusion bioreporters, specific for sugars, polyols, amino acids, organic acids or flavonoids, have been validated in vitro and in vivo. Using different bacterial mutants (nodC, nifH), the process of colonization and symbiosis has been analyzed, revealing compounds important in the different steps of the rhizobial-legume association. Dicarboxylates and sucrose are the main carbon sources within the nodules; in ineffective (nifH) nodules, particularly low levels of sucrose were observed suggesting that plant sanctions affect carbon supply to nodules. In contrast, high myo-inositol levels were observed prior to nodule formation and also in nifH senescent nodules. Amino-acid biosensors showed different patterns: a GABA biosensor was active only inside nodules, whereas the phenylalanine bioreporter showed a high signal also in the rhizosphere. The bioreporters were further validated in vetch, producing similar results. In addition, vetch exhibited a local increase of nod-gene inducing flavonoids at sites where nodules subsequently developed. These bioreporters will be particularly helpful to understand the dynamics of root exudation and the role of different molecules secreted into the rhizosphere.
more...
No comment yet.
Rescooped by Fabiane Vezzani from MycorWeb Plant-Microbe Interactions
Scoop.it!

Secrets of life in the soil

Secrets of life in the soil | Soil Ecology | Scoop.it
Wall, a soil ecologist and environmental scientist at Colorado State University in Fort Collins, has come to this site about an hour east of the campus to collect data for one of her latest experiments. She and her colleagues are creating an artificial drought in a patch of grassland by covering it with temporary shelters. They expect that predatory nematodes will die or enter a type of suspended animation, leaving the parasitic nematodes that prey on plants to dominate the ecosystem. “How do plants respond below-ground to drought?” she wonders.

Wall has been asking — and answering — similar questions about soil for decades. She has become one of the most celebrated and outspoken experts on the hidden biodiversity in dirt, having studied soils and their inhabitants in nearly every corner of the world. She has a special fondness for Antarctica, which she has visited almost every year since 1989. It was there that she and a colleague made a landmark discovery, demonstrating that the soil in one of the driest spots on Earth is home to some animal life and not sterile, as many had thought.

The same drive to challenge orthodoxy also helped her to advance in a field in which women were once rare. “Many times, I felt like I was hitting the glass ceiling and got discouraged,” she says, before emphasizing how things have improved. “Today, I love seeing so many women in Antarctic and other research.”

Via Francis Martin
more...
No comment yet.