scholarly journals Interspecies Social Spreading: Interaction between two sessile soil bacteria leads to emergence of surface motility

2018 ◽  
Author(s):  
Lucy M. McCully ◽  
Adam S. Bitzer ◽  
Sarah C. Seaton ◽  
Leah M. Smith ◽  
Mark W. Silby
Keyword(s):  
Microbial Communities ◽  
Pseudomonas Fluorescens ◽  
Soil Bacteria ◽  
Interspecific Interactions ◽  
Close Association ◽  
Soil Microbiome ◽  
Emergent Properties ◽  
Community Members ◽  
Holistic Understanding ◽  
Nutrient Conditions

AbstractBacteria often live in complex communities in which they interact with other organisms. Consideration of the social environment of bacteria can reveal emergent traits and behaviors that would be overlooked by studying bacteria in isolation. Here we characterize a social trait which emerges upon interaction between the distantly-related soil bacteriaPseudomonas fluorescensPf0-1 andPedobactersp. V48. On hard agar, which is not permissive for motility of the mono-culture of either species, co-culture reveals an emergent phenotype we term ‘interspecies social spreading,’ where the mixed colony spreads across the hard surface. We show that initiation of social spreading requires close association between the two species of bacteria. Both species remain associated throughout the spreading colony, with reproducible and non-homogenous patterns of distribution. The nutritional environment influences social spreading; no social behavior is observed under high nutrient conditions, but low nutrient conditions are insufficient to promote social spreading without high salt concentrations. This simple two-species consortium is a tractable model system that will facilitate mechanistic investigations of interspecies interactions and provide insight into emergent properties of interacting species. These studies will contribute to the broader knowledge of how bacterial interactions influence the functions of communities they inhabit.ImportanceThe wealth of studies on microbial communities has revealed the complexity and dynamics of the composition of communities in many ecological settings. Fewer studies probe the functional interactions of the community members. Function of the community as a whole may not be fully revealed by characterizing the individuals. In our two-species model community, we find an emergent trait resulting from the interaction of the soil bacteriaPseudomonas fluorescensPf0-1 andPedobactersp. V48. Observation of emergent traits suggests there may be many functions of a community that are not predicted based ona prioriknowledge of the community members. These types of studies will provide a more holistic understanding of microbial communities, allowing us to connect information about community composition with behaviors determined by interspecific interactions. These studies increase our ability to understand communities, such as the soil microbiome, plant-root microbiome, and human gut microbiome, with the final goal of being able to manipulate and rationally improve these communities.

scholarly journals Interspecies Social Spreading: Interaction between Two Sessile Soil Bacteria Leads to Emergence of Surface Motility

mSphere ◽  
2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Lucy M. McCully ◽  
Adam S. Bitzer ◽  
Sarah C. Seaton ◽  
Leah M. Smith ◽  
Mark W. Silby
Keyword(s):  
Microbial Communities ◽  
Pseudomonas Fluorescens ◽  
Soil Bacteria ◽  
Interspecific Interactions ◽  
Soil Microbiome ◽  
Emergent Properties ◽  
Community Members ◽  
Content Type ◽  
Holistic Understanding ◽  
Nutrient Conditions

ABSTRACTBacteria often live in complex communities in which they interact with other organisms. Consideration of the social environment of bacteria can reveal emergent traits and behaviors that would be overlooked by studying bacteria in isolation. Here we characterize a social trait which emerges upon interaction between the distantly related soil bacteriaPseudomonas fluorescensPf0-1 andPedobactersp. strain V48. On hard agar, which is not permissive for motility of the monoculture of either species, coculture reveals an emergent phenotype that we term “interspecies social spreading,” where the mixed colony spreads across the hard surface. We show that initiation of social spreading requires close association between the two species of bacteria. Both species remain associated throughout the spreading colony, with reproducible and nonhomogenous patterns of distribution. The nutritional environment influences social spreading: no social behavior is observed under high-nutrient conditions, but low-nutrient conditions are insufficient to promote social spreading without high salt concentrations. This simple two-species consortium is a tractable model system that will facilitate mechanistic investigations of interspecies interactions and provide insight into emergent properties of interacting species. These studies will contribute to the broader knowledge of how bacterial interactions influence the functions of communities they inhabit.IMPORTANCEThe wealth of studies on microbial communities has revealed the complexity and dynamics of the composition of communities in many ecological settings. Fewer studies probe the functional interactions of the community members. Function of the community as a whole may not be fully revealed by characterizing the individuals. In our two-species model community, we find an emergent trait resulting from the interaction of the soil bacteriaPseudomonas fluorescensPf0-1 andPedobactersp. V48. Observation of emergent traits suggests there may be many functions of a community that are not predicted based ona prioriknowledge of the community members. These types of studies will provide a more holistic understanding of microbial communities, allowing us to connect information about community composition with behaviors determined by interspecific interactions. These studies increase our ability to understand communities, such as the soil microbiome, plant-root microbiome, and human gut microbiome, with the final goal of being able to manipulate and rationally improve these communities.

scholarly journals Exploration of social spreading reveals behavior is prevalent among Pedobacter and P. fluorescens isolates, and shows variations in induction of phenotype

2019 ◽  
Author(s):  
Lucy M. McCully ◽  
Jasmine Graslie ◽  
Adam S. Bitzer ◽  
Auður M. Sigurbjörnsdóttir ◽  
Oddur Vilhelmsson ◽  
...  
Keyword(s):  
Social Context ◽  
Microbial Communities ◽  
Soil Bacteria ◽  
Close Contact ◽  
Microbial Interactions ◽  
Emergent Properties ◽  
High Nutrient ◽  
Agar Surface ◽  
Nutritional Environment ◽  
Emergent Community

AbstractWithin soil, bacteria are naturally found in multi-species communities, where interactions can lead to emergent community properties. It is critical that we study bacteria in a social context to investigate community-level functions. We previously showed that when co-cultured, Pseudomonas fluorescens Pf0-1 and Pedobacter sp. V48 engage in interspecies social spreading on a hard agar surface, a behavior which required close contact and was dependent on the nutritional environment. In this study, we investigate whether the ability to participate in social spreading is widespread among P. fluorescens and Pedobacter isolates, and whether the requirements for interaction vary. We find that this phenotype is not restricted to the interaction between P. fluorescens Pf0-1 and Pedobacter sp. V48, but is a more prevalent behavior found in one clade in the P. fluorescens group and two clades in the Pedobacter genus. We also discovered that the interaction with certain Pedobacter isolates occurred without close contact, indicating induction of spreading by a putative diffusible signal. As is the case for ISS by Pf0-1+V48, motility of all interacting pairs is influenced by the environment, with no spreading behaviors observed under high nutrient conditions. While Pf0-1+V48 require low nutrient but high NaCl conditions, in the broader range of interacting pairs this requirement for low nutrient and high salt was variable. The prevalence of motility phenotypes observed in this study and found within the literature indicates that community-induced locomotion in general, and social spreading in particular, is likely important within the environment. It is crucial that we continue to study microbial interactions and their emergent properties to gain a fuller understanding of the functions of microbial communities.

scholarly journals Long-Term Amelioration Practices Reshape the Soil Microbiome in a Coastal Saline Soil and Alter the Richness and Vertical Distribution Differently Among Bacterial, Archaeal, and Fungal Communities

2022 ◽  
Vol 12 ◽  
Author(s):  
Ruibo Sun ◽  
Xiaogai Wang ◽  
Yinping Tian ◽  
Kai Guo ◽  
Xiaohui Feng ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Soil Salinity ◽  
Saline Soil ◽  
Saline Water ◽  
Soil Microbial Communities ◽  
Soil Microbiome ◽  
Economic Losses ◽  
Saline Water Irrigation ◽  
Coastal Saline Soil ◽  
Plastic Mulching

Globally soil salinity is one of the most devastating environmental stresses affecting agricultural systems and causes huge economic losses each year. High soil salinity causes osmotic stress, nutritional imbalance and ion toxicity to plants and severely affects crop productivity in farming systems. Freezing saline water irrigation and plastic mulching techniques were successfully developed in our previous study to desalinize costal saline soil. Understanding how microbial communities respond during saline soil amelioration is crucial, given the key roles soil microbes play in ecosystem succession. In the present study, the community composition, diversity, assembly and potential ecological functions of archaea, bacteria and fungi in coastal saline soil under amelioration practices of freezing saline water irrigation, plastic mulching and the combination of freezing saline water irrigation and plastic mulching were assessed through high-throughput sequencing. These amelioration practices decreased archaeal and increased bacterial richness while leaving fungal richness little changed in the surface soil. Functional prediction revealed that the amelioration practices, especially winter irrigation with saline water and film mulched in spring, promoted a community harboring heterotrophic features. β-null deviation analysis illustrated that amelioration practices weakened the deterministic processes in structuring coastal saline soil microbial communities. These results advanced our understanding of the responses of the soil microbiome to amelioration practices and provided useful information for developing microbe-based remediation approaches in coastal saline soils.

scholarly journals Spatially-resolved correlative microscopy and microbial identification reveals dynamic depth- and mineral-dependent anabolic activity in salt marsh sediment

2020 ◽  
Author(s):  
Jeffrey Marlow ◽  
Rachel Spietz ◽  
Keun-Young Kim ◽  
Mark Ellisman ◽  
Peter Girguis ◽  
...  
Keyword(s):  
Salt Marsh ◽  
Microbial Communities ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Community Members ◽  
Marsh Sediment ◽  
Anabolic Activity ◽  
Salt Marsh Sediment ◽  
Rrna Gene Sequencing ◽  
And Function

AbstractCoastal salt marshes are key sites of biogeochemical cycling and ideal systems in which to investigate the community structure of complex microbial communities. Here, we clarify structural-functional relationships among microorganisms and their mineralogical environment, revealing previously undescribed metabolic activity patterns and precise spatial arrangements within salt marsh sediment. Following 3.7-day in situ incubations with a non-canonical amino acid that was incorporated into new biomass, samples were embedded and analyzed by correlative fluorescence and electron microscopy to map the microscale arrangements of anabolically active and inactive organisms alongside mineral grains. Parallel sediment samples were examined by fluorescence-activated cell sorting and 16S rRNA gene sequencing to link anabolic activity to taxonomic identity. Both approaches demonstrated a rapid decline in the proportion of anabolically active cells with depth into salt marsh sediment, from ∼60% in the top cm to 10-25% between 2-7 cm. From the top to the bottom, the most prominent active community members shifted from sulfur cycling phototrophic consortia, to sulfate-reducing bacteria likely oxidizing organic compounds, to fermentative lineages. Correlative microscopy revealed more abundant (and more anabolically active) organisms around non-quartz minerals including rutile, orthoclase, and plagioclase. Microbe-mineral relationships appear to be dynamic and context-dependent arbiters of biogeochemical cycling.Statement of SignificanceMicroscale spatial relationships dictate critical aspects of a microbiome’s inner workings and emergent properties, such as evolutionary pathways, niche development, and community structure and function. However, many commonly used methods in microbial ecology neglect this parameter – obscuring important microbe-microbe and microbe-mineral interactions – and instead employ bulk-scale methodologies that are incapable of resolving these intricate relationships.This benchmark study presents a compelling new approach for exploring the anabolic activity of a complex microbial community by mapping the precise spatial configuration of anabolically active organisms within mineralogically heterogeneous sediment through in situ incubation, resin embedding, and correlative fluorescence and electron microscopy. In parallel, active organisms were identified through fluorescence-activated cell sorting and 16S rRNA gene sequencing, enabling a powerful interpretive framework connecting location, identity, activity, and putative biogeochemical roles of microbial community members.We deploy this novel approach in salt marsh sediment, revealing quantitative insights into the fundamental principles that govern the structure and function of sediment-hosted microbial communities. In particular, at different sediment horizons, we observed striking changes in the proportion of anabolically active cells, the identities of the most prominent active community members, and the nature of microbe-mineral affiliations. Improved approaches for understanding microscale ecosystems in a new light, such as those presented here, reveal environmental parameters that promote or constrain metabolic activity and clarify the impact that microbial communities have on our world.

Pseudomonas fluorescens C7R12 type III secretion system impacts mycorrhization of Medicago truncatula and associated microbial communities

Mycorrhiza ◽  
2016 ◽  
Vol 27 (1) ◽  
pp. 23-33 ◽  
Author(s):  
Amandine Viollet ◽  
Barbara Pivato ◽  
Christophe Mougel ◽  
Jean-Claude Cleyet-Marel ◽  
Cécile Gubry-Rangin ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Pseudomonas Fluorescens ◽  
Medicago Truncatula ◽  
Type Iii Secretion ◽  
Type Iii Secretion System ◽  
Secretion System ◽  
Type Iii

In Situ Gene Expression in Mixed-Culture Biofilms: Evidence of Metabolic Interactions between Community Members

1998 ◽  
Vol 64 (2) ◽  
pp. 721-732 ◽  
Author(s):  
Søren Møller ◽  
Claus Sternberg ◽  
Jens Bo Andersen ◽  
Bjarke Bak Christensen ◽  
Juan Luis Ramos ◽  
...  
Keyword(s):  
Gene Expression ◽  
Microbial Communities ◽  
Pure Culture ◽  
Fluorescent Protein ◽  
Confocal Laser ◽  
Specific Gene ◽  
Community Members ◽  
Metabolic Interactions ◽  
Green Fluorescent

ABSTRACT Microbial communities growing in laboratory-based flow chambers were investigated in order to study compartmentalization of specific gene expression. Among the community members studied, the focus was in particular on Pseudomonas putida and a strain of anAcinetobacter sp., and the genes studied are involved in the biodegradation of toluene and related aromatic compounds. The upper-pathway promoter (Pu) and themeta-pathway promoter (Pm) from the TOL plasmid were fused independently to the gene coding for the green fluorescent protein (GFP), and expression from these promoters was studied inP. putida, which was a dominant community member. Biofilms were cultured in flow chambers, which in combination with scanning confocal laser microscopy allowed direct monitoring of promoter activity with single-cell spatial resolution. Expression from thePu promoter was homogeneously induced by benzyl alcohol in both community and pure-culture biofilms, while the Pmpromoter was induced in the mixed community but not in a pure-culture biofilm. By sequentially adding community members, induction ofPm was shown to be a consequence of direct metabolic interactions between an Acinetobacter species and P. putida. Furthermore, in fixed biofilm samples organism identity was determined and gene expression was visualized at the same time by combining GFP expression with in situ hybridization with fluorescence-labeled 16S rRNA targeting probes. This combination of techniques is a powerful approach for investigating structure-function relationships in microbial communities.

scholarly journals Bio-organic fertilizers stimulate indigenous soil Pseudomonas populations to enhance plant disease suppression

Microbiome ◽  
2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Chengyuan Tao ◽  
Rong Li ◽  
Wu Xiong ◽  
Zongzhuan Shen ◽  
Shanshan Liu ◽  
...  
Keyword(s):  
Microbial Communities ◽  
Plant Pathogens ◽  
Organic Fertilizer ◽  
Soil Microbial Communities ◽  
Plant Diseases ◽  
Disease Suppression ◽  
Organic Fertilizers ◽  
Soil Microbiome ◽  
Soil Microbial ◽  
Bioorganic Fertilizer

Abstract Background Plant diseases caused by fungal pathogen result in a substantial economic impact on the global food and fruit industry. Application of organic fertilizers supplemented with biocontrol microorganisms (i.e. bioorganic fertilizers) has been shown to improve resistance against plant pathogens at least in part due to impacts on the structure and function of the resident soil microbiome. However, it remains unclear whether such improvements are driven by the specific action of microbial inoculants, microbial populations naturally resident to the organic fertilizer or the physical-chemical properties of the compost substrate. The aim of this study was to seek the ecological mechanisms involved in the disease suppressive activity of bio-organic fertilizers. Results To disentangle the mechanism of bio-organic fertilizer action, we conducted an experiment tracking Fusarium wilt disease of banana and changes in soil microbial communities over three growth seasons in response to the following four treatments: bio-organic fertilizer (containing Bacillus amyloliquefaciens W19), organic fertilizer, sterilized organic fertilizer and sterilized organic fertilizer supplemented with B. amyloliquefaciens W19. We found that sterilized bioorganic fertilizer to which Bacillus was re-inoculated provided a similar degree of disease suppression as the non-sterilized bioorganic fertilizer across cropping seasons. We further observed that disease suppression in these treatments is linked to impacts on the resident soil microbial communities, specifically by leading to increases in specific Pseudomonas spp.. Observed correlations between Bacillus amendment and indigenous Pseudomonas spp. that might underlie pathogen suppression were further studied in laboratory and pot experiments. These studies revealed that specific bacterial taxa synergistically increase biofilm formation and likely acted as a plant-beneficial consortium against the pathogen. Conclusion Together we demonstrate that the action of bioorganic fertilizer is a product of the biocontrol inoculum within the organic amendment and its impact on the resident soil microbiome. This knowledge should help in the design of more efficient biofertilizers designed to promote soil function.

scholarly journals Visualizing Microbial Community Dynamics via a Controllable Soil Environment

mSystems ◽  
2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Arunima Bhattacharjee ◽  
Dusan Velickovic ◽  
Thomas W. Wietsma ◽  
Sheryl L. Bell ◽  
Janet K. Jansson ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Microbial Community ◽  
Microbial Communities ◽  
Community Dynamics ◽  
Soil Microbial Communities ◽  
Soil Microbiome ◽  
Soil Core ◽  
Soil Microbial ◽  
Functional Relationships ◽  
Microbial Community Dynamics

ABSTRACT Understanding the basic biology that underpins soil microbiome interactions is required to predict the metaphenomic response to environmental shifts. A significant knowledge gap remains in how such changes affect microbial community dynamics and their metabolic landscape at microbially relevant spatial scales. Using a custom-built SoilBox system, here we demonstrated changes in microbial community growth and composition in different soil environments (14%, 24%, and 34% soil moisture), contingent upon access to reservoirs of nutrient sources. The SoilBox emulates the probing depth of a common soil core and enables determination of both the spatial organization of the microbial communities and their metabolites, as shown by confocal microscopy in combination with mass spectrometry imaging (MSI). Using chitin as a nutrient source, we used the SoilBox system to observe increased adhesion of microbial biomass on chitin islands resulting in degradation of chitin into N-acetylglucosamine (NAG) and chitobiose. With matrix-assisted laser desorption/ionization (MALDI)-MSI, we also observed several phospholipid families that are functional biomarkers for microbial growth on the chitin islands. Fungal hyphal networks bridging different chitin islands over distances of 27 mm were observed only in the 14% soil moisture regime, indicating that such bridges may act as nutrient highways under drought conditions. In total, these results illustrate a system that can provide unprecedented spatial information about interactions within soil microbial communities as a function of changing environments. We anticipate that this platform will be invaluable in spatially probing specific intra- and interkingdom functional relationships of microbiomes within soil. IMPORTANCE Microbial communities are key components of the soil ecosystem. Recent advances in metagenomics and other omics capabilities have expanded our ability to characterize the composition and function of the soil microbiome. However, characterizing the spatial metabolic and morphological diversity of microbial communities remains a challenge due to the dynamic and complex nature of soil microenvironments. The SoilBox system, demonstrated in this work, simulates an ∼12-cm soil depth, similar to a typical soil core, and provides a platform that facilitates imaging the molecular and topographical landscape of soil microbial communities as a function of environmental gradients. Moreover, the nondestructive harvesting of soil microbial communities for the imaging experiments can enable simultaneous multiomics analysis throughout the depth of the SoilBox. Our results show that by correlating molecular and optical imaging data obtained using the SoilBox platform, deeper insights into the nature of specific soil microbial interactions can be achieved.

scholarly journals Resilience and Assemblage of Soil Microbiome in Response to Chemical Contamination Combined with Plant Growth

2019 ◽  
Vol 85 (6) ◽  
Author(s):  
Shuo Jiao ◽  
Weimin Chen ◽  
Gehong Wei
Keyword(s):  
Microbial Communities ◽  
Soil Microbial Communities ◽  
Soil Microbiome ◽  
Chemical Contamination ◽  
Plant Interactions ◽  
Soil Microbial Diversity ◽  
Soil Microbial ◽  
Microbial Responses ◽  
Legume Plants ◽  
Functional Profiles

ABSTRACT A lack of knowledge of the microbial responses to environmental change at the species and functional levels hinders our ability to understand the intrinsic mechanisms underlying the maintenance of microbial ecosystems. Here, we present results from temporal microcosms that introduced inorganic and organic contaminants into agro-soils for 90 days, with three common legume plants. Temporal dynamics and assemblage of soil microbial communities and functions in response to contamination under the influence of growth of different plants were explored via sequencing of the 16S rRNA amplicon and by shotgun metagenomics. Soil microbial alpha diversity and structure at the taxonomic and functional levels exhibited resilience patterns. Functional profiles showed greater resilience than did taxonomic ones. Different legume plants imposed stronger selection on taxonomic profiles than on functional ones. Network and random forest analyses revealed that the functional potential of soil microbial communities was fostered by various taxonomic groups. Betaproteobacteria were important predictors of key functional traits such as amino acid metabolism, nucleic acid metabolism, and hydrocarbon degradation. Our study reveals the strong resilience of the soil microbiome to chemical contamination and sensitive responses of taxonomic rather than functional profiles to selection processes induced by different legume plants. This is pivotal to develop approaches and policies for the protection of soil microbial diversity and functions in agro-ecosystems with different response strategies from global environmental drivers, such as soil contamination and plant invasion. IMPORTANCE Exploring the microbial responses to environmental disturbances is a central issue in microbial ecology. Understanding the dynamic responses of soil microbial communities to chemical contamination and the microbe-soil-plant interactions is essential for forecasting the long-term changes in soil ecosystems. Nevertheless, few studies have applied multi-omics approaches to assess the microbial responses to soil contamination and the microbe-soil-plant interactions at the taxonomic and functional levels simultaneously. Our study reveals clear succession and resilience patterns of soil microbial diversity and structure in response to chemical contamination. Different legume plants exerted stronger selection processes on taxonomic than on functional profiles in contaminated soils, which could benefit plant growth and fitness as well as foster the potential abilities of hydrocarbon degradation and metal tolerance. These results provide new insight into the resilience and assemblage of soil microbiome in response to environmental disturbances in agro-ecosystems at the species and functional levels.

scholarly journals Mapping metabolic activity at single cell resolution in intact volcanic fumarole sediment

2020 ◽  
Vol 367 (1) ◽  
Author(s):  
Jeffrey J Marlow ◽  
Isabella Colocci ◽  
Sean P Jungbluth ◽  
Nils Moritz Weber ◽  
Amy Gartman ◽  
...  
Keyword(s):  
Structure Function ◽  
Microbial Communities ◽  
Metabolic Activity ◽  
Point Sources ◽  
Emergent Properties ◽  
Spatial Relationships ◽  
Environmental Regime ◽  
Novel Approach ◽  
Stable Conditions ◽  
Metabolite Exchange

ABSTRACT Interactions among microorganisms and their mineralogical substrates govern the structure, function and emergent properties of microbial communities. These interactions are predicated on spatial relationships, which dictate metabolite exchange and access to key substrates. To quantitatively assess links between spatial relationships and metabolic activity, this study presents a novel approach to map all organisms, the metabolically active subset and associated mineral grains, all while maintaining spatial integrity of an environmental microbiome. We applied this method at an outgassing fumarole of Vanuatu's Marum Crater, one of the largest point sources of several environmentally relevant gaseous compounds, including H2O, CO2 and SO2. With increasing distance from the sediment-air surface and from mineral grain outer boundaries, organism abundance decreased but the proportion of metabolically active organisms often increased. These protected niches may provide more stable conditions that promote consistent metabolic activity of a streamlined community. Conversely, exterior surfaces accumulate more organisms that may cover a wider range of preferred conditions, implying that only a subset of the community will be active under any particular environmental regime. More broadly, the approach presented here allows investigators to see microbial communities ‘as they really are’ and explore determinants of metabolic activity across a range of microbiomes.

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