The Experts below are selected from a list of 339 Experts worldwide ranked by ideXlab platform
Stephen D J Archer - One of the best experts on this subject based on the ideXlab platform.
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airborne microbial transport limitation to isolated antarctic Soil Habitats
Nature microbiology, 2019Co-Authors: Kevin C Lee, Stephen D J Archer, Tancredi Caruso, Teruya Maki, C K Lee, Craig S Cary, Don A Cowan, Fernando T Maestre, Stephen B PointingAbstract:Dispersal is a critical yet poorly understood factor underlying macroecological patterns in microbial communities1. Airborne microbial transport is assumed to occupy a central role in determining dispersal outcomes2,3, and extra-range dispersal has important implications for predicting ecosystem resilience and response to environmental change4. One of the most pertinent biomes in this regard is Antarctica, given its geographic isolation and vulnerability to climate change and human disturbance5. Here, we report microbial diversity in near-ground and high-altitude air above the largest ice-free Antarctic habitat, as well as that of underlying Soil microbial communities. We found that persistent local airborne inputs were unable to fully explain Antarctic Soil community assembly. Comparison with airborne microbial diversity from high-altitude and non-polar sources suggests that strong selection occurs during long-range atmospheric transport. The influence of selection during airborne transit and at sink locations varied between microbial phyla. Overall, the communities from this isolated Antarctic ecosystem displayed limited connectivity to the non-polar microbial pool, and alternative sources of recruitment are necessary to fully explain extant Soil diversity. Our findings provide critical insights into the role of airborne transport limitation in determining microbial biogeographic patterns.
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microbial dispersal limitation to isolated Soil Habitats in the mcmurdo dry valleys of antarctica
bioRxiv, 2018Co-Authors: Kevin C Lee, Stephen D J Archer, Tancredi Caruso, Teruya Maki, C K Lee, Don A Cowan, Fernando T Maestre, Stephen B PointingAbstract:Dispersal is a critical yet poorly understood factor underlying macroecological patterns in microbial communities. Airborne microbial transport is assumed to occupy a central role in determining dispersal outcomes and extra-range dispersal has important implications for predicting ecosystem resilience and response to environmental change. One of the most pertinent biomes in this regard is Antarctica given its geographic isolation and vulnerability to climate change and human disturbance. Here we report the first characterisation of microbial diversity in near-ground and high-altitude air above a typical Antarctic Dry Valley as well as that of underlying Soil microbial communities. We found that persistent airborne inputs were unable to fully explain local Soil community assembly. Comparison with airborne microbial diversity from non-polar sources suggests that strong selection occurs during atmospheric transport resulting in regionally isolated airborne inputs and highly specialized Soil communities where fungi displayed greater isolation than bacteria from non-polar sources. Overall microbial communities from this isolated Antarctic ecosystem displayed limited connectivity to the global microbial pool. Our findings provide critical insights to forecast the potential outcomes for microbial communities of climate change-mediated shifts in air circulation to the Dry Valleys, the largest ice-free region of Antarctica.
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Soil microbial Habitats in an extreme desert mars analogue environment
bioRxiv, 2018Co-Authors: Kimberley A Warrenrhodes, Kevin C Lee, Stephen D J Archer, Donnabella C Lacap, Linda Ngboyle, David Wettergreen, Kris Zacny, Cecilia Demergasso, Jeff Moersch, Guillermo ChongAbstract:The Atacama Desert represents one of the closest terrestrial analogues to Mars' surface and subsurface environments. Understanding the distribution and drivers of life in the Soil may thus give critical clues on how to search for biosignatures in the Martian regolith with the upcoming Mars2020 and ExoMars missions. Here, we show the result of a field experiment that combined an autonomous rover-mounted drill with ground-truth from manual sample recovery to characterize the most extreme Atacama Desert Soil Habitats. Distinct habitability zones were identified in Soil horizons to 800mm depth in two Mars-like terrains, an evaporite-rich playa and a gravel desert pavement. Highly specialised bacterial community assembly was depth-dependent and strongly influenced by Soil geochemistry linked to moisture. Colonisation was also patchy and several putatively lifeless zones that correlated with high salt content were encountered. We demonstrate a clear linkage between geochemistry, moisture and biocomplexity in Mars analogue Soils, and resident bacterial communities displayed putative traits that might allow survival in the Martian regolith. We discuss implication of the findings in extreme desert geobiological systems and their scientific and operational significance for upcoming Mars missions.
L W Duncan - One of the best experts on this subject based on the ideXlab platform.
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entomopathogenic nematodes phoretic paenibacillus spp and the use of real time quantitative pcr to explore Soil food webs in florida citrus groves
Journal of Invertebrate Pathology, 2011Co-Authors: Raquel Camposherrera, Fahiem E Elborai, Robin J Stuart, J H Graham, L W DuncanAbstract:Quantitative real-time PCR (qPCR) is a powerful tool to detect and quantify species of cryptic organisms such as bacteria, fungi and nematodes from Soil samples. As such, qPCR offers new opportunities to study the ecology of Soil Habitats by providing a single method to characterize communities of diverse organisms from a sample of DNA. Here we describe molecular tools to detect and quantify two bacteria (Paenibacillus nematophilus and Paenibacillus sp.) phoretically associated with entomopathogenic nematodes (EPNs) in the families Heterorhabditidae and Steinernematodae. We also extend the repertoire of species specific primers and TaqMan® probes for EPNs to include Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae and Steinernema scapterisci, all widely distributed species used commercially for biological control. Primers and probes were designed from the ITS rDNA region for the EPNs and the 16S rDNA region for the bacteria. Standard curves were established using DNA from pure cultures of EPNs and plasmid DNA from the bacteria. The use of TaqMan probes in qPCR resolved the non-specificity of EPN and some bacterial primer amplifications whereas those for Paenibacillus sp. also amplified Paenibacillus thiaminolyticus and Paenibacillus popilliae, two species that are not phoretically associated with nematodes. The primer-probe sets for EPNs were able to accurately detect three infective juvenile EPNs added to nematodes recovered from Soil samples. The molecular set for Paenibacillus sp. detected the bacterium attached to Steinernema diaprepesi suspended in water or added to nematodes recovered from Soil samples but its detection decreased markedly in the Soil samples, even when a nested PCR protocol was employed. Using qPCR we detected S. scapterisci at low levels in a citrus grove, which suggested natural long-distance spread of this exotic species, which is applied to pastures and golf courses to manage mole crickets (Scapteriscus spp.). Paenibacillus sp. (but not P. nematophilus) was detected in low quantities in the same survey but was unrelated to the spatial pattern of S. diaprepesi. The results of this research validate several new tools for studying the ecology of EPNs and their phoretic bacteria.
Christopher Ngosong - One of the best experts on this subject based on the ideXlab platform.
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influence of management intensity and environmental conditions on microbiota in biological Soil crust and crust free Soil Habitats of temperate forests
Soil Biology & Biochemistry, 2020Co-Authors: Christopher Ngosong, Thomas Buse, Martin Ewald, Andreas Richter, Karin Glaser, Ingo Schoning, Liliane RuessAbstract:Abstract The microbiota in three distinct terrestrial Habitats (biological Soil crusts – BSC, crust-adhering Soil beneath BSC – trans, and crust-free Soil close to BSC – Soil) was studied in 33 temperate forest stands differing in management intensity (ForMI). Specific lipid fractions and respective marker fatty acids were used to determine microbial biomass and community structure (phospholipid fatty acids – PLFA), energy reserves (neutral lipid fatty acids – NLFA), and community level lipid profiles (CLLP) of nematodes and enchytraeids. The density and diversity of nematode fauna were additionally determined morphologically. The highest total amounts of PLFA and NLFA occurred in the BSC, followed by Soil and trans Habitats, indicating stronger effects of Habitats than forest management intensity. This corresponds to the distribution pattern of bacterial PLFA that dominated the Soil microbiota. The highest nematode population density occurred in the BSC, followed by Soil and trans. The BSC was dominated by bacterial feeders and omnivores, while plant feeding nematodes were most frequent in the crust-free Soil habitat. The highest biomass of photoautotrophs also occurred in the BSC, followed by the crust-adhering and crust-free Soil Habitats. Redundancy analysis indicated strong effect of ForMI and total N on Soil PFLAs and NFLAs across Habitats. The C:N and C:S ratios were important for the separation of NLFAs while P:S accounted for the separation of PLFAs. Bacterial and fungal PLFAs largely separated the microbial community across Habitats, and particularly between BSC and trans Habitats. The separation of nematodes and enchytraeids by CLLP was less pronounced, and most distinct between the crust-free Soil and BSC or crust-adhering Soil Habitats. Overall, BSC and crust-adhering Soil Habitats provide different suitability for microbiota, resulting in specifically adapted communities that are shaped by the management intensity and nutrient availability.
Fahiem E Elborai - One of the best experts on this subject based on the ideXlab platform.
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entomopathogenic nematodes phoretic paenibacillus spp and the use of real time quantitative pcr to explore Soil food webs in florida citrus groves
Journal of Invertebrate Pathology, 2011Co-Authors: Raquel Camposherrera, Fahiem E Elborai, Robin J Stuart, J H Graham, L W DuncanAbstract:Quantitative real-time PCR (qPCR) is a powerful tool to detect and quantify species of cryptic organisms such as bacteria, fungi and nematodes from Soil samples. As such, qPCR offers new opportunities to study the ecology of Soil Habitats by providing a single method to characterize communities of diverse organisms from a sample of DNA. Here we describe molecular tools to detect and quantify two bacteria (Paenibacillus nematophilus and Paenibacillus sp.) phoretically associated with entomopathogenic nematodes (EPNs) in the families Heterorhabditidae and Steinernematodae. We also extend the repertoire of species specific primers and TaqMan® probes for EPNs to include Heterorhabditis bacteriophora, Steinernema carpocapsae, Steinernema feltiae and Steinernema scapterisci, all widely distributed species used commercially for biological control. Primers and probes were designed from the ITS rDNA region for the EPNs and the 16S rDNA region for the bacteria. Standard curves were established using DNA from pure cultures of EPNs and plasmid DNA from the bacteria. The use of TaqMan probes in qPCR resolved the non-specificity of EPN and some bacterial primer amplifications whereas those for Paenibacillus sp. also amplified Paenibacillus thiaminolyticus and Paenibacillus popilliae, two species that are not phoretically associated with nematodes. The primer-probe sets for EPNs were able to accurately detect three infective juvenile EPNs added to nematodes recovered from Soil samples. The molecular set for Paenibacillus sp. detected the bacterium attached to Steinernema diaprepesi suspended in water or added to nematodes recovered from Soil samples but its detection decreased markedly in the Soil samples, even when a nested PCR protocol was employed. Using qPCR we detected S. scapterisci at low levels in a citrus grove, which suggested natural long-distance spread of this exotic species, which is applied to pastures and golf courses to manage mole crickets (Scapteriscus spp.). Paenibacillus sp. (but not P. nematophilus) was detected in low quantities in the same survey but was unrelated to the spatial pattern of S. diaprepesi. The results of this research validate several new tools for studying the ecology of EPNs and their phoretic bacteria.
John H Willis - One of the best experts on this subject based on the ideXlab platform.
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major qtl controls adaptation to serpentine Soils in mimulus guttatus
Molecular Ecology, 2018Co-Authors: Jessica P Selby, John H WillisAbstract:: Spatially varying selection is a critical driver of adaptive differentiation. Yet, there are few examples where the fitness effects of naturally segregating variants that contribute to local adaptation have been measured in the field. Plant adaptation to harsh Soil Habitats provides an ideal study system for investigating the genetic basis of local adaptation. The work presented here identifies a major locus underlying adaptation to serpentine Soils in Mimulus guttatus and estimates the strength of selection on this locus in native field sites. Reciprocal transplant and common-garden studies show that serpentine and nonserpentine populations of M. guttatus differ in their ability to survive on serpentine Soils. We directly mapped these field survival differences by performing a bulk segregant analysis with F2 survivors from a field transplant study and identify a single QTL where individuals that are homozygous for the nonserpentine allele do not survive on serpentine Soils. Genotyping the survivors from an independent mapping population reveals that this same QTL controls serpentine tolerance in a second, geographically distant population. Finally, we show that this QTL controls tolerance to Soil properties, as opposed to some other aspect of the field sites that may differ, by performing a laboratory-based common-garden experiment in native serpentine Soils that replicates the survival differences observed in the field. These results indicate that despite the myriad chemical and physical challenges plants face in serpentine Habitats, adaptation to these Soils in M. guttatus has a simple genetic basis.
