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Filtering by: Creator Marshall, Nicole S. Remove constraint Creator: Marshall, Nicole S. Degree Field Botany and Plant Pathology Remove constraint Degree Field: Botany and Plant Pathology Degree Level Doctoral Remove constraint Degree Level: Doctoral

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  • Systematic, genomic, and transcriptomic analysis of mycoparasitic Tolypocladium species and their Elaphomyces hosts

    Creator:
    Quandt, C. Alisha
    Abstract:
    Fungi in the genus Tolypocladium are diverse in their host associations, but the predominant ecologies include parasites of the ectomycorrhizal genus Elaphomyces and pathogens of insects. The aim of this dissertation research is to examine the evolution of these fungi and their host associations. To accomplish this several lines of...
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    Dissertation
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    committee members, Aaron Liston, Carol Mallory-Smith, Chris Marshall, and Pat Muir for their encouragement

  • Understory herb and shrub responses to root trenching, pre-commercial thinning, and canopy closure in Douglas-fir forest of the western Cascades, Oregon

    Creator:
    Lindh, Briana C.
    Abstract:
    This thesis examines factors limiting understory herb presence and flowering in young second-growth Douglas-fir (Pseudotsuga menziesii) forests on the west side of the Cascade Mountains, Oregon, USA. I studied the belowground effects of canopy trees on understory herbs and shrubs in old-growth forests using trenched plots from which tree roots...
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    Dissertation
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    Forests of the Western Cascades, Oregon. Abstract approved: Patricia S. Muir This thesis examines

  • Seed and seedling ecology of Artemisia tridentata in a restoration context

    Creator:
    Wijayratne, Upekala C.
    Abstract:
    The semi-arid sagebrush steppe ecosystem is one of the largest biomes in North America. The steppe provides critical habitat and forage for wildlife and is economically important to recreation and livestock industries. However, the ecosystem is threatened primarily due to several negative effects associated with expansion of the exotic annual...
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    Dissertation
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    : _____________________________________________________________________ David A. Pyke Patricia S. Muir The semi-arid sagebrush steppe ecosystem is one of

  • Host and Pathogen Genetics in the Sharp Eyespot Disease of Wheat

    Creator:
    Liu, Jiang
    Abstract:
    Wheat sharp eyespot (SES), caused by the soil-borne fungus Rhizoctonia cerealis is a common stem disease of wheat globally. The disease caused a severe and extensive epidemic throughout the Willamette Valley of Oregon in 2014 and has remained one of the most important wheat diseases in this region. However, litte...
    Resource Type:
    Dissertation
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    , Dr. David Vaquez, Dr. Nicole Anderson, Kathryn Sackett, Dr. Paul Severns, Dr. Karasi Mills, Evan

  • Responses of forest understory plants to burial by volcanic tephra from Mount St. Helens, Washington

    Creator:
    Antos, Joseph A.
    Abstract:
    The effects of burial by tephra (volcanic aerial ejecta) on forest understory plants were examined northeast of Mount St. Helens, Washington, in the area where the 18 May 1980 eruption deposited tephra but did not destroy canopy trees. At six sites along a tephra depth gradient from 2-15 cm, understory...
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    Dissertation
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    graduate committee: Drs. Peter S. Dawson, Jerry F. Franklin, Robert E. Frenkel, J. Herbert Huddleston

  • Post-dispersal seed fates in a Western Oregon native prairie

    Creator:
    Clark, Deborah L.
    Abstract:
    Knowledge of post-dispersal seed fates and other regeneration characteristics is crucial for predicting abundances and distributions of populations and, ultimately, community species composition and diversity. Seed fate studies, however, are rare primarily due to the difficulty of determining seed fates and causes of mortality. This thesis investigated post-dispersal seed fates...
    Resource Type:
    Dissertation
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    , Mark V. Wilson, Kenneth B. Johnson, Patricia S. Muir, Donald B. Zobel, and Jeffrey C. Miller, for

  • Pathogenic variability and adaptation of Septoria tritici to different wheat cultivars

    Creator:
    Ahmed, Hafiz Uddin
    Abstract:
    Experiments were done to determine pathogenic variability and pathogenic adaptation of Septoria tritici to different wheat cultivars. Fifteen S. tritici isolates from California, Oregon, and Texas were evaluated on seedlings of two sets of geographically diverse wheat cultivars under greenhouse conditions. Significant isolate effects, cultivar effects, and isolate X cultivar...
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    Dissertation
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    disease-free conditions (Nelson & Marshall, 1990). Resistance to S. tritici has been reported by

  • A two-component regulatory system controlling antibiotic production by Pseudomonas flourescens Pf-5

    Creator:
    Corbell, Nathan
    Abstract:
    Tn5 mutagenesis of apdA (for antibiotic production) and deletion of gacA (for global antibiotic and cyanide) resulted in the same pleiotropic phenotype in Pseudomonas fluorescens (i.e. production of an array of secondary metabolites including the antibiotics pyrrolnitrin, pyoluteorin, and 2,4-diacetylphloroglucinol as well as a tryptophan-side-chain oxidase, hydrogen cyanide, and an...
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    Dissertation
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    motif was fused to the glutathione S-transferase protein. The glutathione S-transferase GacA C

  • A G-type Lectin Receptor-like Kinase Associated with Septoria Canker Resistance and Susceptibility Described using Multi-omics and Biotechnology

    Creator:
    Lenz, Ryan R.
    Abstract:
    Managers of forest and plantation ecosystems are encountering growing problems involving plant pathogens and the expanding geographic ranges of these pathogens. Historically unexposed stands are exceptionally vulnerable when a non-native pathogen is introduced because these pathogens can cause devastating disease in a host population that lacks co-evolved resistance mechanisms. One...
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    Dissertation
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    relates to resistance and susceptibility mechanisms deployed in poplar stems in response to S. musiva

  • Secondary Metabolism in Tolypocladium : Characterization, Ecology, Evolution and Regulation

    Creator:
    Blount, Rheannon Rua
    Abstract:
    An increased understanding of secondary metabolism in fungi is important for both biological and societal reasons. The ascomycete genus, Tolypocladium, is an ideal system to explore secondary metabolism characterization, ecology, evolution and regulation. The genus produces and has the genomic potential to produce a wide array of metabolites. Paired with...
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    Dissertation
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    always saying yes to fun; Milan Milovancev and Nicole LeBlanc for calm, reasonable support and physical