Index Catalog // ScholarsArchive@OSU

Genomic Resources for Phylogenetics, Species Delimitation, and Geographic Localization of Neotropical Tree Species Cedrela odorata L. (Meliaceae)

Creator:: Finch, Kristen N.
Abstract:: Biodiversity loss is of global concern, and is due in part to deforestation and high consumer demand for wood and wood products. The neotropical tree species Cedrela odorata (“Spanish cedar” or “cedro”) is economically valuable for its wood and faces threats of overexploitation. Due to strong similarities in wood features...
Resource Type:: Dissertation

Structure and Function of Foliar Fungal Communities of Populus trichocarpa Across its Native Range, Pacific Northwest, USA

Creator:: Barge, Edward G.
Abstract:: Foliar fungi – pathogens, endophytes, epiphytes – form taxonomically diverse communities that affect plant health and productivity. The composition of foliar fungal communities is variable at spatial scales both small (e.g., individual plants) and large (e.g., continents). However, few studies have focused on how environmental factors and host plant traits...
Resource Type:: Dissertation

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

Lichen Studies of Tropical Dry Forest: A Systematic and Ecological Approach

Creator:: Miranda-González, Ricardo
Abstract:: In recent years, our ecological knowledge of tropical dry forests has increased dramatically. However, whole components of the ecosystem, like lichenized fungi, remain mostly unknown. Crustose lichens in these forests are so abundant, that they are responsible for the characteristic appearance of a “white bark forest” during the dry season....
Resource Type:: Dissertation

Diagnosis and Etiology of a Soilborne Disease Complex of Winter Squash (Cucurbita maxima) in the Willamette Valley, OR

Creator:: Rivedal, Hannah M.
Abstract:: Winter squash (Cucurbita maxima) grown in Oregon’s Willamette Valley for edible seed, frozen foods, and fresh markets is susceptible to an undiagnosed soilborne disease. Diseased squash fields exhibit symptoms of stunting, root and crown rot, vascular discoloration, and late-season wilt, which in extreme cases can lead to total crop failure....
Resource Type:: Dissertation

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...
Resource Type:: Dissertation

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...
Resource Type:: Dissertation

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

Candidate Genes Associated with Blister Rust Resistance in Whitebark Pine (Pinus albicaulis) Revealed through de novo Transcriptome Assembly and Differential Gene Expression Analysis

Creator:: Bair, Zolton J.
Abstract:: Whitebark pine (Pinus albicaulis) is an iconic North American high-elevation tree species currently threatened by climate change, mountain pine beetle, and white pine blister rust (WPBR), a lethal disease caused by the non-native fungal pathogen Cronartium ribicola. In collaboration with the USDA Forest Service Dorena Genetic Resource Center, germplasm was...
Resource Type:: Dissertation

Realized and potential climate responses of lichen and bryophyte communities in a national forest inventory

Creator:: Smith, Robert J.
Abstract:: Climate and terrestrial vegetation have had mutual feedbacks for nearly five hundred million years, yet both are now departing from recent historical norms, with uncertain implications for forest ecosystems. This dissertation outlines the current and potential future climate responses of lichen and bryophyte communities in the United States as part...
Resource Type:: Dissertation

Unearthing the Cretaceous Diversification of Cornales

Creator:: Atkinson, Brian A.
Abstract:: The order Cornales (dogwoods) is the earliest diverging lineage within the most diverse group of flowering plants, the asterids (>80,000 species). Although molecular phylogenetics have significantly improved our understanding of cornalean systematics, early phylogenetic relationships remain uncertain due to an initial rapid radiation. The fossil record of Cornales is extensive...
Resource Type:: Dissertation

Identification of Endogenous and Exogenous Pararetroviruses in Red Raspberry (Rubus idaeus L.) and Blueberry (Vaccinium corymbosum L.)

Creator:: Diaz Lara, Alfredo
Abstract:: The Pacific Northwest (Oregon and Washington in the United States and British Columbia in Canada) is one of the major producers of red raspberry (Rubus idaeus L.) and blueberry (Vaccinium corymbosum L.) in the world. The expansion of growing area with these crops has resulted in the emergence of new...
Resource Type:: Dissertation

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

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...
Resource Type:: Dissertation

Genomic Investigations of Diversity within the Milkweed Genus Asclepias, at Multiple Scales

Creator:: Weitemier, Kevin A.
Abstract:: At a time when the biodiversity on Earth is being rapidly lost, new technologies and methods in genomic analysis are fortunately allowing scientists to catalog and explore the diversity that remains more efficiently and precisely. The studies in this dissertation investigate genomic diversity within the milkweed genus, Asclepias, at multiple...
Resource Type:: Dissertation

Characterization of the transition to the progamic phase in Zea mays pollen

Creator:: Smyth, Johanna C.
Abstract:: The transition of mature pollen to the progamic phase represents an important step in the regulation of plant sexual reproduction. The progamic phase encompasses the initiation of pollen tube germination, growth of the pollen tube through the stigma (the silk in maize) and concludes with fertilization of the female gametophyte....
Resource Type:: Dissertation

Dynamics of Zymoseptoria tritici Fungicide Resistance in the Willamette Valley of Oregon

Creator:: Hagerty, Christina H.
Abstract:: The development of resistance to multiple fungicide classes is currently limiting disease management options for many pathogens, while the discovery of new fungicide classes has become less frequent. To address this pressing issue, a three-part study with different layers of complexity, objectives, and experimental approaches was conducted using the model...
Resource Type:: Dissertation

Biological Soil Crusts of the Great Basin : An Examination of their Distribution, Recovery from Disturbance and Restoration

Creator:: Condon, Lea A.
Abstract:: We are at risk of losing the sagebrush steppe in the floristic Great Basin to the invasion of Bromus tectorum L., cheatgrass. The floristic Great Basin includes the Central Basin and Range, the Northern Basin and Range, and the Snake River Plain. The Great Basin receives most of its precipitation...
Resource Type:: Dissertation

Understanding Host-Pathogen Interactions in the Sphaerulina musiva-Populus Pathosystem

Creator:: Dunnell, Kelsey Liann
Abstract:: Host-parasite interactions between the pathogen, Sphaerulina musiva, and its host, Populus spp., were examined in a series of studies. In the first study, variation in resistance of Populus nigra from 7 locations in Europe was differentiated based on the parameters cankers per cm and disease severity score. The analysis evaluated...
Resource Type:: Dissertation

Overwintering of Erysiphe necator and Inoculum Monitoring for Decision Aids

Creator:: Thiessen, Lindsey D.
Abstract:: Grape powdery mildew (Erysiphe necator) causes economic damages to grape worldwide due to the cost of management and injury to berries. Each region where European grapevine (Vitis vinifera) is grown experiences a unique epidemic, and disease prediction models that are based on empirical correlations of weather data to disease fail...
Resource Type:: Dissertation

Mulching to Manage Mummy Berry of Blueberry

Creator:: Florence, Jade
Abstract:: Monilinia vaccinii-corymbosi pseudosclerotia overwinter on the soil surface and produce apothecia in early spring, providing primary inoculum for Mummy Berry Disease of blueberry. Burial under 2.5 cm of soil or the absence of light have previously been identified as critical factors preventing the development of apothecia. Mulches were applied to...
Resource Type:: Dissertation

Symbiosis in the Pacific Ring of Fire : evolutionary-biology of Rhizopogon subgenus Villosuli as mutualists of Pseudotsuga

Creator:: Mujic, Alija Bajro
Abstract:: Rhizopogon is a large genus of ectomycorrhizal (EM) fungi that grows in association with host trees of the family Pinaceae. We have conducted a series of studies investigating the ecology and evolutionary biology of the EM symbiosis shared between R. subgenus Villosuli and trees of the genus Pseudotsuga. Two members...
Resource Type:: Dissertation

Yosemite region nitrogen deposition and patterns in the composition of lichen communities

Creator:: Hutten, Martin
Abstract:: This dissertation describes patterns in epiphytic macrolichen community composition along a nitrogen deposition gradient in the Yosemite region of the Sierra Nevada in California. This region is part of the largest federal air quality Class 1 designated air-shed in the western United States, covering the entire crest of the Sierra...
Resource Type:: Dissertation

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...
Resource Type:: Dissertation

Phytophthora species and riparian alder tree damage in western Oregon

Creator:: Sims, Laura L.
Abstract:: The genus Phytophthora contains some of the most destructive pathogens of forest trees, including the most destructive pathogen of alder in recent times, Phytophthora alni. Alder trees were reported to be suffering from canopy dieback in riparian ecosystems in western Oregon, which prompted a survey of alder health and monitoring...
Resource Type:: Dissertation

Lichen communities and caribou habitat in Denali National Park and Preserve, Alaska, USA

Creator:: Nelson, Peter R.
Abstract:: Lichens play many important roles in subarctic terrestrial ecosystems by fixing nitrogen, colonizing rock and gravel, stabilizing otherwise bare soil, adding significantly to vegetation biodiversity and serving as the primary food for caribou in the winter. In these chapters, I analyzed lichen community and ecological trait structure along environmental gradients,...
Resource Type:: Dissertation

Studies on the centromere-specific histone, CenH3, of Neurospora crassa and related ascomycetes

Creator:: Phatale, Pallavi A.
Abstract:: In eukaryotes, the defined loci on each chromosome, the centromeres, accomplish the critical task of correct cell division. In some organisms, centromeres are composed of a euchromatic central core region embedded in a stretch of heterochromatin and the inheritance and maintenance of centromeres are controlled by dynamic epigenetic phenomena. Although...
Resource Type:: Dissertation

Characterization of fungal and bacterial communities associated with mat-forming ectomycorrhizal fungi from old-growth stands in the H.J. Andrews Experimental Forest

Creator:: Hesse, Cedar N.
Abstract:: Mat-forming ectomycorrhizal (EcM) fungi represent a prevalent constituent of many temperate forest ecosystems and create dramatic changes in soil structure and chemistry. EcM mat soil have been shown to have increased microbial respiration rates and have been hypothesized to harbor unique assemblages of fungi and bacteria. The objectives of this...
Resource Type:: Dissertation

TonB-dependent outer-membrane proteins of Pseudomonas fluorescens : diverse and redundant roles in iron acquisition

Creator:: Hartney, Sierra L.
Abstract:: Pseudomonas is a diverse genus of Gram-negative bacteria that includes pathogens of plants, insects, and humans as well as environmental strains with no known pathogenicity. Pseudomonas fluorescens itself encompasses a heterologous group of bacteria that are prevalent in soil and on foliar and root surfaces of plants. Some strains of...
Resource Type:: Dissertation

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...
Resource Type:: Dissertation

Impact of raspberry bushy dwarf virus, raspberry leaf mottle virus, and raspberry latent virus on plant growth and fruit crumbliness in red raspberry (Rubus idaeus L.) 'Meeker'

Creator:: Quito-Avila, Diego F.
Abstract:: The United States is the third-largest producer of raspberries in the world. Washington State leads the nation in red raspberry (Rubus idaeus L.) production. 'Meeker', the most grown red raspberry cultivar in the Pacific Northwest (Washington, Oregon and British Columbia, Canada) is highly susceptible to Raspberry crumbly fruit, a virusinduced...
Resource Type:: Dissertation

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...
Resource Type:: Dissertation

Cryptogam communities in forest and steppe ecosystems of Oregon, USA

Creator:: Root, Heather T.
Abstract:: I focus on addressing knowledge gaps relating to management of cryptogams in Oregon's public lands in Pseudotsuga menziesii-Tsuga heterophylla forests on the west side of the Cascade Range and dryland steppe in the Cascade Range's rainshadow. While a great deal of research has illustrated the importance of late-successional forests for...
Resource Type:: Dissertation

Plastome phylogenomics in the genus Pinus using massively parallel sequencing technology

Creator:: Parks, Matthew Benjamin
Abstract:: This thesis summarizes work completed over the previous four years primarily focusing on chloroplast phylogenomic inquiry into the genus Pinus and related Pinaceae outgroups using next-generation sequencing on Illumina platforms. During the time of our work, Illumina sequence read lengths have essentially been limited to 25 to 100 base pairs,...
Resource Type:: Dissertation

Ecological thresholds, climate extremes, and tree species' distributions across the Pacific coastal United States

Creator:: Lintz, Heather E.
Abstract:: Species' distributions across the landscape are perhaps the least understood yet most conspicuous features of life on earth. Ecologists have long studied species' distributions; yet, many questions remain about why species occur where they do. Such questions persist largely because species' distributions are complex systems with challenging properties like non-linearity,...
Resource Type:: Dissertation

Advances in molecular systematics of clavicipitaceous fungi (Sordariomycetes: Hypocreales)

Creator:: Kepler, Ryan M.
Abstract:: Historical concepts of Clavicipitaceae have included a broad range of species that display diverse morphologies, ecological modes and host associations. When subjected to multigene phylogenetic investigation of evolutionary history, the family was found to be polyphyletic, largely driven by diversity in the genus Cordyceps, previously containing over 400 taxa. The...
Resource Type:: Dissertation

Reproduction, demography, and habitat characterization of Astragalus peckii (Fabaceae), a rare central Oregon endemic

Creator:: Martin, Elizabeth F.
Abstract:: With little previous research on Astragalus peckii (Fabaceae), a state-listed Threatened species in Oregon, I investigated three facets of its biology which are integral to the conservation and management of the species. First, a four-year demographic study of two large populations revealed increasing population growth at one site (Chiloquin) and...
Resource Type:: Dissertation

Evolutionary relationships and an investigation of sympatric speciation within Limnanthaceae

Creator:: Meyers, Stephen C.
Abstract:: Limnanthes floccosa ssp. floccosa and L. floccosa ssp. grandiflora are two of five subspecies of Limnanthes floccosa endemic to vernal pools in southern Oregon and northern California. Three seasons of monitoring natural populations have quantified that L. floccosa ssp. grandiflora is always found growing sympatrically with L. floccosa ssp. floccosa...
Resource Type:: Dissertation

Search Constraints

Search Results

Limit your search