111 |
Benzylsuccinate Synthase is Post-Transcriptionally Regulated in the Toluene-Degrading Denitrifier Magnetospirillum sp. Strain 15-1Meyer-Cifuentes, Ingrid, Gruhl, Sylvie, Haange, Sven-Bastiaan, Lünsmann, Vanessa, Jehmlich, Nico, von Bergen, Martin, Heipieper, Hermann J., Müller, Jochen A. 20 April 2023 (has links)
The facultative denitrifying alphaproteobacterium Magnetospirillum sp. strain 15-1 had been isolated from the hypoxic rhizosphere of a constructed wetland model fed with toluene. This bacterium can catabolize toluene anaerobically but not aerobically. Here, we used strain 15-1 to investigate regulation of expression of the highly oxygen-sensitive glycyl radical enzyme benzylsuccinate synthase, which catalyzes the first step in anaerobic toluene degradation. In cells growing aerobically with benzoate, the addition of toluene resulted in a ~20-fold increased transcription of bssA, encoding for the catalytically active subunit of the enzyme. Under anoxic conditions, bssA mRNA copy numbers were up to 129-fold higher in cells growing with toluene as compared to cells growing with benzoate. Proteomics showed that abundance of benzylsuccinate synthase increased in cells growing anaerobically with toluene. In contrast, peptides of this enzyme were never detected in oxic conditions. These findings show that synthesis of benzylsuccinate synthase was under stringent post-transcriptional control in the presence of oxygen, which is a novel level of regulation for glycyl radical enzymes.
|
112 |
Targeting the Active Rhizosphere Microbiome of Trifolium pratense in Grassland Evidences a Stronger-Than-Expected Belowground Biodiversity-Ecosystem Functioning LinkWahdan, Sara Fareed Mohamed, Heintz-Buschart, Anna, Sansupa, Chakriya, Tanunchai, Benjawan, Wu, Yu-Ting, Schädler, Martin, Noll, Matthias, Purahong, Witoon, Buscot, François 27 March 2023 (has links)
The relationship between biodiversity and ecosystem functioning (BEF) is a central issue
in soil and microbial ecology. To date, most belowground BEF studies focus on the
diversity of microbes analyzed by barcoding on total DNA, which targets both active and
inactive microbes. This approach creates a bias as it mixes the part of the microbiome
currently steering processes that provide actual ecosystem functions with the part not
directly involved. Using experimental extensive grasslands under current and future
climate, we used the bromodeoxyuridine (BrdU) immunocapture technique combined
with pair-end Illumina sequencing to characterize both total and active microbiomes
(including both bacteria and fungi) in the rhizosphere of Trifolium pratense. Rhizosphere
function was assessed by measuring the activity of three microbial extracellular enzymes
(β-glucosidase, N-acetyl-glucosaminidase, and acid phosphatase), which play central
roles in the C, N, and P acquisition. We showed that the richness of overall and specific
functional groups of active microbes in rhizosphere soil significantly correlated with the
measured enzyme activities, while total microbial richness did not. Active microbes of
the rhizosphere represented 42.8 and 32.1% of the total bacterial and fungal taxa,
respectively, and were taxonomically and functionally diverse. Nitrogen fixing bacteria
were highly active in this system with 71% of the total operational taxonomic units (OTUs)
assigned to this group detected as active. We found the total and active microbiomes to
display different responses to variations in soil physicochemical factors in the grassland,
but with some degree of resistance to a manipulation mimicking future climate. Our
findings provide critical insights into the role of active microbes in defining soil ecosystem
functions in a grassland ecosystem. We demonstrate that the relationship between
biodiversity-ecosystem functioning in soil may be stronger than previously thought.
|
113 |
Transgenerational Effects of Kin Recognition in Plants: Soil Conditioning by an Invasive PlantWu, Albert January 2021 (has links)
Monospecific stands of invasive plant species are found in nearly all known ecosystems and can cause permanent lasting ecosystem damage via deleterious effects in soils. These deleterious soil effects are a proposed mechanism which drives invasions by plants and are known to be influenced by kin recognition in plants. Uncovering whether invasive species utilize kin recognition to facilitate their own ecological persistence via soil conditioning will allow us to better understand the drivers of plant invasions and help combat them. In my master’s thesis, I examined the role of kin recognition and kin selection on soil effects. I grew groups of Potentilla recta in groups of maternal half-sibs or strangers to condition the soil. I then grew a second generation of plants in that conditioned soil to determine the impacts of soil conditioning effects on plant performance. I found soil conditioning by groups of plants affected the performance of a second generation of plants based on the relatedness of the conditioning plants. Further, these soil effects of conditioning selectively benefit future individuals of a subsequent generation based on their relatedness. Moreover, these soil effects only existed in soil that has not been sterilized, indicating these soil effects depended on soil microbes. / Thesis / Master of Biological Science (MBioSci) / Invasive plants form dense stands of same-species individuals that can cause lasting deleterious effects to the soil. These deleterious soil effects have been proposed as a mechanism driving plant invasions. In my master’s thesis, I examined the role of kin recognition and kin selection on soil effects. I first grew groups of Potentilla recta in groups of maternal half-sibs or strangers to condition the soil, and then grew a second generation of plants in that conditioned soil to determine the impacts on plant performance. I found that soil influenced by groups of related plants affect increased the performance of a second generation of plants, particularly if the second generation was related to the first. Moreover, these soil effects only existed in soil that has not been sterilized, indicating these soil effects depended on soil microbes. I found that these soil effects of conditioning selectively benefited future individuals of a subsequent generation based on their relatedness.
|
114 |
Long Term Glyphosate Effects on Roundup Ready Soybean Rhizosphere MicroorganismsLee, Nathan Robert William 20 December 2018 (has links)
No description available.
|
115 |
INVESTIGATIONS INTO THE USE OF TREES FOR PHYTOREMEDIATION OF PAH CONTAMINATED SOILSMUELLER, KEVIN E. 30 September 2005 (has links)
No description available.
|
116 |
Needle-Type Sensor For In Situ 3-D Multi-Analyte MappingChoi, Woo-Hyuck January 2011 (has links)
No description available.
|
117 |
Soil nitrogen dynamics affected by fine roots of a canopy tree species in a northern hardwood forest in eastern Hokkaido, Japan / 北海道東部の北方広葉樹林において林冠木の細根が影響を及ぼす土壌窒素動態Nakayama, Masataka 23 March 2022 (has links)
京都大学 / 新制・課程博士 / 博士(農学) / 甲第23946号 / 農博第2495号 / 新制||農||1090(附属図書館) / 学位論文||R4||N5381(農学部図書室) / 京都大学大学院農学研究科森林科学専攻 / (主査)教授 舘野 隆之輔, 教授 北島 薫, 教授 德地 直子 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM
|
118 |
Exploring candidate genes and rhizosphere microbiome in relation to iron cycling in Andean potatoesXiao, Hua 05 June 2017 (has links)
Fe biofortification of potato is a promising strategy to prevent Fe deficiency worldwide either through traditional breeding or biotechnological approaches. These approaches require the identification of candidate genes to uptake, transport and store Fe in potato tubers. We employed multiple approaches including SNP genotyping, QTL analysis, identifying genes orthologous to Arabidopsis ferrome, yeast complementation assay and genetic transformation to avoid the limitation from a single approach. We revealed several candidate genes potentially associated with potato plant Fe acquisition, PGSC0003DMG400024976 (metal transporter), PGSC0003DMG400013297 (oligopeptide transporter), PGSC0003DMG400021155 (IRT1) and IRTunannotated (an ortholog to the IRT gene that is not annotated in the potato genome). The microorganisms in the rhizosphere react intensely with the various metabolites released by plant roots in a variety of ways such as positive, negative, and neutral. These interactions can influence the uptake and transport of micronutrients in the plant roots. Therefore, the contribution of soil microorganisms in the rhizosphere to improve Fe supply of plants may play a key role in Fe biofortification, especially under real world field-based soil scenarios. We thus investigated rhizosphere microbial community diversity in Andean potato landraces to understand the role of plant-microbial interaction in potato Fe nutrient cycling. From the analysis of the high-throughput Illumina sequences of 16S and ITS region of ribosomal RNA gene, we found that both potato landraces with low and high Fe content in tubers and a landrace on which low or high Fe content fertilizer was applied to the leaf surface had large impacts on the rhizosphere fungal community composition. Indicator species analysis (ISA) indicated that Operational Taxonomic Units (OTUs) contributing most to these impacts were closely related to Eurotiomycetes and Leotiomycetes in the phylum Ascomycota, Glomeromycetes in the phylum Glomeromycota and Microbotryomycetes in the phylum Basidiomycota. Lots of species from these groups have been shown to regulate plant mineral nutrient cycling. Our research revealed potential candidate genes and fungal taxa involved in the potato plant Fe nutrient dynamics, which provides new insights into crop management and breeding strategies for sustainable Fe fortification in agricultural production. / Ph. D.
|
119 |
Investigating Structure and Function of Rhizosphere Associated Microbial Communities in Natural and Managed Plant SystemsRodrigues, Richard Rosario 21 April 2016 (has links)
Many plants, especially grasses, have Nitrogen (N) as their growth-limiting nutrient. Large amounts of N fertilizer (>100 kg N ha-1) are used in managed systems to maximize crop productivity. However, the plant captures less than 50% of the (~12 million tons per year, U.S.) applied N-fertilizer. The remaining mobile N lost through leaching and denitrification accumulates in waterways and the atmosphere, respectively. Losses of fertilizers create environmental and economic concerns globally and create conditions that support the invasion of exotic plants in the natural landscapes. There is thus a need to come up with biological solutions to better manage nitrogen for plant growth and ecosystem sustainability. Microbial communities in the rhizosphere are known to potentially have beneficial effects on plant growth. Diazotrophs, for example, are bacteria that can convert the atmospheric nitrogen to ammonia, a process called 'nitrogen fixation.' Utilizing the natural process of associative nitrogen fixation to support most of the plant's N needs would substantially reduce fertilizer use and thus reduce production and environmental costs. The goal of this dissertation was to determine the structure and function of root-zone microbial communities for increasing productivity of native plants. Towards this end, we study the root-zone bacterial and fungal communities of native and exotic invasive plants. This study identifies that shifts in rhizosphere microbial communities are associated with invasion and highlights the importance of rhizosphere associated structure and function of microbes. A study of root-zone associated microbes in switchgrass (Panicum virgatum L.) - a U.S. native, warm-season, perennial, bioenergy crop indicates that high biomass yield and taller growth are associated with increased plant N-demand and supportive of bacteria with greater rates of N2-fixation in the rhizosphere. Another crucial outcome of the thesis is a better description of the core and cultivar-specific taxa that comprise the switchgrass root-zone associated microbiome. The work in this dissertation has brought us closer to designing N supply strategies by utilizing the natural microbial communities to balance the N-cycle in agroecosystems and support a sustainable environment. / Ph. D.
|
120 |
Fine root traits, belowground interactions and competition effects on the rhizosphere of <i>Fagus sylvatica</i> and <i>Fraxinus excelsior</i> saplingsBeyer, Friderike 05 December 2012 (has links)
No description available.
|
Page generated in 0.0715 seconds