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Filtering by: Creator Grünwald, N. J. Remove constraint Creator: Grünwald, N. J. Resource Type Dissertation Remove constraint Resource Type: Dissertation

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  • Development and Application of Tools for Genetic Analysis of Clonal Populations

    Creator:
    Kamvar, Zhian N.
    Abstract:
    Research on the population genetics of microbial organisms requires the use of specialized analyses designed for clonal organisms to avoid violating the assumptions of traditional population genetic models. The tools necessary for performing these analyses existed as a set of unrelated software with non-overlapping capabilities and did not cover all...
    Resource Type:
    Dissertation
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    and tested the code. Zhian N. Kamvar and Niklaus J. Grünwald conceived, discussed implications, and

  • Development of Computational, Visualization, and Molecular Tools for Fungal and Oomycete Community Ecology

    Creator:
    Foster, Zachary Stephen Longiaru
    Abstract:
    Oomycetes are an important group of organisms with a variety of ecological roles similar to fungi. Although many are well-studied plant pathogens known for their devastating effects on agricultural systems, most are little-studied saprobes and parasites of plants and animals in nearly every ecosystem on earth. The advent of affordable...
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    Dissertation
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    Oomycete Community Ecology Abstract approved: Niklaus J. Grünwald Oomycetes are an important group of

  • Inferring Patterns and Processes of Emergence in Clonal Phytophthora Epidemics using Population Genomic Approaches

    Creator:
    Cauldron, Nicholas C.
    Abstract:
    Oomycete and fungal pathogens threaten food, fiber, and forests around the world. With climate change, these pathogens are expected to emerge more frequently. Evolution can facilitate their emergence through mechanisms such as mutations that change or expand host range. Characterizing evolutionary mechanisms in plant pathogens will contribute to our ability...
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    Dissertation
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    . Abstract approved: ______________________________________________________ Niklaus J. Grünwald

  • Phylogeography and Evolution of Effector Genes in Phytophthora Species

    Creator:
    Shakya, Shankar K.
    Abstract:
    Plant pathogens in the genus Phytophthora are known to cause disease on field crops, nursery plants, and forest trees. The best known example probably is Phytophthora infestans, which triggered the infamous Irish potato famine. Other important Phytophthora species include: P. ramorum (sudden oak death pathogen), P. sojae (soybean root rot...
    Resource Type:
    Dissertation
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    . Abstract approved: ______________________________________________________ Niklaus J. Grünwald

  • Integration of Evolutionary Theory and Genomics to Understand Processes Involved in Host Adaptation and Divergence in Phytophthora Plant Pathogens

    Creator:
    Tabima, Javier F.
    Abstract:
    Modern plant pathology benefits from integrating methods and concepts from evolutionary biology. For example, evolutionary concepts are used to identify and examine species boundaries of plant pathogens, recognize processes underlying pathogen biogeography, identify traits that characterize emerging species, and discover new molecular interactions that originate under processes of selection. In...
    Resource Type:
    Dissertation
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    Niklaus J. Grünwald Modern plant pathology benefits from integrating methods and concepts from

  • Movement of zoospores of Phytophthora citricola in saturated porous media

    Creator:
    Ochiai, Naoyuki
    Abstract:
    The genus Phytophthora comprises numerous plant pathogens in both natural and managed ecosystems. For Phytophthora spp. that infect roots, dispersal occurs in soil water through a combination of advection and swimming of specialized motile propagules (zoospores). Specific biological and physico-chemical processes, however, remain poorly understood, due to difficulties in studying...
    Resource Type:
    Dissertation
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    ………………………………………………………………… 47 2.4 (A) Typical trajectories (n = 444) of colloids passing between a bead pair whose center-to

  • Genetic Structure in Populations of the Douglas-fir Swiss Needle Cast Fungus Nothophaeocryptopus gaeumannii

    Creator:
    Bennett, Patrick I.
    Abstract:
    The fungus Nothophaeocryptopus gaeumannii is the causative agent of Swiss needle cast (SNC), a foliar disease of Douglas-fir. Disease is characterized by premature loss of foliage and reduced growth resulting from the inhibition of photosynthesis due to the occlusion of stomata by the ascocarps of N. gaeumannii. Although the disease...
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    Dissertation
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    manuscript. Chapter 3: J. K. Stone sampled Douglas-fir foliage from New Zealand, isolated N

  • Insights into the pathology and epidemiology of Phytophthora ramorum, causal agent of sudden oak death

    Creator:
    Daniels, Hazel A.
    Abstract:
    Sudden oak death is caused by the clonally reproducing generalist oomycete Phytophthora ramorum. The pathogen can infect more than 130 different plant hosts including Quercus spp., Larix kaempferi, and Notholithocarpus densiflorus, as well as common nursery genera such as Rhododendron and Camelia, where it causes symptoms ranging from bleeding cankers...
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    Dissertation
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    , Niklaus Grünwald, Posy Busby, and Jim Kiser for their willingness to dig deep and engage with my

  • The Primary Disease Gradient of Wheat Stripe Rust (Puccinia striiformis f. sp. tritici) Across Spatial Scales

    Creator:
    Farber, Daniel
    Abstract:
    Wheat stripe rust (WSR), also called yellow rust of wheat (Tricitum spp.), causal agent Puccinia striiformis f.sp. tritici (Pst), is a foliar disease of major economic importance on wheat, especially grown in temperate locations. WSR causes major losses of wheat yield, estimated at nearly $ 1 billion per year, and...
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    Dissertation
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    Johnson, Dr. Niklaus Grunwald, Dr. Patrick De Leenheer, and Dr. Daniel Luoma. Additionally, I am very

  • The epidemiology of sudden oak death in Oregon forests

    Creator:
    Peterson, Ebba K.
    Abstract:
    The phytopathogen Phytophthora ramorum (Werres, DeCock & Man in't Veld), causal agent of Sudden Oak Death (SOD) of oaks (Quercus spp.) and tanoaks (Notholithocarpus densiflorus syn. Lithocarpus densiflorus), is established in coastal forests of the western United States. Since the discovery of SOD in the Douglas-fir / tanoak forests of...
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    Dissertation
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    Jennifer Parke, Chris Mundt, Jean Hall, Nik Grünwald, Michael Wing and Dave Shaw. I have enjoyed and