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The Future Of The Big Sagebrush Ecosystem: Plant Community Response To Grazing, Wildfire, And Invasive Annual Grass In A Changing Climate, Margaret Eleanor England

Theses, Dissertations and Capstones

Climate change is increasingly affecting the plant communities across the world. In the Western United States, these changes are affecting plant communities and their risk of invasive species, as well as the frequency and severity of wildfire. Big sagebrush (Artemisia tridentata Nutt.) ecosystems of the Western United States are facing threats of increasingly frequent wildfire and invasion of the annual grass cheatgrass (Bromus tectorum L.), which may be exacerbated by global climate change. Past studies have found cheatgrass to exhibit a positive feedback loop with wildfire, and climate change is expected to facilitate expansion of the cheatgrass …

Thermal Tolerances Of The Invasive Macrophyte Hydrilla Verticillata, Joshua Williams

Graduate Research Showcase

Invasive species often rapidly spread due to their ability to adapt to a wide range of habitats they can occupy and lack of competition. Hydrilla verticillata is an invasive aquatic macrophyte that has spread across the United States due to human activities. Like many aquatic plants, Hydrilla has the ability to reproduce through fragmentation of the mother plant. In this method, Hydrilla fragments are then dispersed by water current to other areas where they can settle and grow. To date, little is known about the abiotic conditions that may restrict the spread of invasive Hydrilla. However, compared to other macrophytes …

Environmental Gradients Impact Key Leaf Traits In Riparian Trees, Amanda Malone

Electronic Theses and Dissertations

Specific leaf area (SLA) reflects a plant’s carbon investment per area and relates to generalized leaf economics spectrum growth strategies (LES). To fill gaps of knowledge about intraspecific SLA variation and why it is often inconsistent with the LES, we studied the response of two riparian tree species along the urban-rural gradient in Northeastern Colorado: an invasive, nitrogen-fixer with broad tolerances and a nitrogen-limited and shade-intolerant native. Despite these differences, the two species responded similarly, apart from the response to the urban-rural gradient, in which lower nitrogen in rural areas was associated with a more conservative strategy in the native …

Fddm1 And Fddm2, Two Sgs3-Like Proteins, Function As A Complex To Affect Dna Methylation In Arabidopsis, Shengjun Li, Weilong Yang, Yunfeng Liu, Guangyong Li, Xiang Liu, Yaling Liu, James R. Alfano, Chi Zhang, Bin Yu

Center for Plant Science Innovation: Faculty Publications

DNA methylation is an important epigenetic modification required for the specific regulation of gene expression and the maintenance of genome stability in plants and animals. However, the mechanism of DNA demethylation remains largely unknown. Here, we show that two SGS3-like proteins, FACTOR OF DNA DEMETHYLATION 1 (FDDM1) and FDDM2, negatively affect the DNA methylation levels at ROS1-dependend DNA loci in Arabidopsis. FDDM1 binds dsRNAs with 50 overhangs through its XS (rice gene X and SGS3) domain and forms a heterodimer with FDDM2 through its XH (rice gene X Homology) domain. A lack of FDDM1 or FDDM2 increased DNA methylation levels …

Qteller: A Tool For Comparative Multi-Genomic Gene Expression Analysis, Margaret R. Woodhouse, Shatabdi Sen, David Schott, John L. Portwood Ii, Michael Freeling, Justin W. Walley, Carson M. Andorf, James Schnable

Center for Plant Science Innovation: Faculty Publications

Motivation: Over the last decade, RNA-Seq whole-genome sequencing has become a widely used method for measuring and understanding transcriptome-level changes in gene expression. Since RNA-Seq is relatively inexpensive, it can be used on multiple genomes to evaluate gene expression across many different conditions, tissues and cell types. Although many tools exist to map and compare RNA-Seq at the genomics level, few web-based tools are dedicated to making data generated for individual genomic analysis accessible and reusable at a gene-level scale for comparative analysis between genes, across different genomes and meta-analyses. Results: To address this challenge, we revamped the comparative gene …

A Phytobacterial Tir Domain Effector Manipulates Nad+ To Promote Virulence, Samuel Eastman, Thomas Smith, Mark A. Zaydman, Panya Kim, Samuel Martinez, Neha Damaraju, Aaron Diantonio, Jeffrey Milbrandt, Thomas Clemente, James R. Alfano, Ming Guo

Department of Agronomy and Horticulture: Faculty Publications

The Pseudomonas syringae DC3000 type III effector HopAM1 suppresses plant immunity and contains a Toll/interleukin-1 receptor (TIR) domain homologous to immunity-related TIR domains of plant nucleotide-binding leucine-rich repeat receptors that hydrolyze nicotinamide adenine dinucleotide (NAD+) and activate immunity. In vitro and in vivo assays were conducted to determine if HopAM1 hydrolyzes NAD+ and if the activity is essential for HopAM1’s suppression of plant immunity and contribution to virulence. HPLC and LC-MS were utilized to analyze metabolites produced from NAD+ by HopAM1 in vitro and in both yeast and plants. Agrobacterium-mediated transient expression and in planta inoculation assays were performed to …

Geospatial Data Trees 1981, Grace K. Attea, Ryan W. Mcewan, John L. Vankat

Data Files for Old-Growth Deciduous Forest Dynamics Archive: Hueston Woods

Location and demographic data collected for each individual tree in 1981 in Hueston Woods State Nature Preserve. These maps were digitized from the historical field maps to a GIS shapefile for each sampling year. Geographic Coordinate System: GCS_North_American_1983. Projected Coordinate System: NAD_1983_StatePlane_Ohio_South_FIPS_3402 (meters).

Predicting Munsell Color For Turfgrass Leaves, William L. Berndt, Roch E. Gaussoin

Department of Agronomy and Horticulture: Faculty Publications

Linking turfgrass color to hue, value, chroma (H V/C) in the Munsell Plant Tissue Color Book is a visual comparison process for specifying and communicating plant color. If subjectivity of visual comparison can be mitigated, then accuracy of color matching may be improved. Research was conducted to develop an algorithm predicting H V/C from CIE-xyY color (xyY) in digital images of leaves of four turfgrasses. First, value-chroma (V/C) arrays for Munsell hue groups 5Y, 2.5GY, 5GY, 7.5GY, 10GY, and 2.5G were converted to xyY. Next, chromaticity (xy) plots from each array were fitted with …

Degradation And Nitrogen Cycling In The Context Of Biodiversity-Ecosystem Function Relationships In The Inquiline Bacterial Community Of Darlingtonia Californica, Megan Teigen

Cal Poly Humboldt theses and projects

Biodiversity-ecosystem function (BEF) research aims to explain how species and their environments interact with each other. Microbial communities engage in vital biogeochemical pathways in a variety of natural ecosystems, and yet there are large knowledge gaps about the specific metabolic pathways in which they are involved. Degradation specifically contributes to nitrogen cycling globally through the breakdown of large organic nitrogen compounds into small inorganic nitrogen that is necessary for the survival of many other organisms. In this study, I focused on the degradative function of the inquiline microbial communities found within the carnivorous pitcher plant, Darlingtonia californica. Darlingtonia grows in …

Characterization Of Salt And Drought Tolerance In Sunflower (Helianthus Annuus L.), Sevgi Saylak

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Consequent to the increasing world population, food sources are needed to be increased to meet the nutritional needs. However, due to natural processes and agricultural activities, the most destructive environmental factors that limit crop production, soil salinity, and drought-exposed areas are growing. As one of the major oilseed crops, sunflower (Helianthus annuus L.), is considered to be moderately tolerant to salt and drought. Although it can grow in arid to semi-arid regions, increasing salinity and drought might adversely affect sunflower production. This study aimed to investigate several sunflower germplasms' morphological responses to salt and drought stresses. For this purpose, …

Geomorphic Gradients In Shallow Seagrass Carbon Stocks, Jahson Berhane Alemu, Siti Maryam Yaakub, Erik S. Yando, Rachel Yu San Lau, Cheng Chang Lim, Jun Yu Puah, Daniel A. Friess

Biological Sciences Faculty Publications

Seagrass meadows are important sinks of organic carbon (C_org), in particular the near-surface C_org pool (≤ 15 cm) compared to deeper sediments. Near-surface carbon is highly susceptible to disturbance and loss to the atmosphere, however, inadequate accounting for variability in this pool of carbon limits their uptake into carbon accounting frameworks. We therefore investigated the spatial variability in seagrass near-surface C_org and biomass C_org across different geomorphic (estuary, lagoonal and reef-associated) and community typologies (pioneer and persistent). Near-surface C_org stock in vegetated areas (25.78 Mg C_org ha⁻¹ ± 26.64) was twice that …

Targeting Transgenic Proteins To The Mitochondria In Plants, Susan Qudus, Jeffrey P. Mower

Honors Program: Senior Projects (Public)

Cytoplasmic male sterility (CMS) in plants can convert an individual into female through sterilization of the male reproductive parts, creating an inability to produce functional pollen. In nature, this is advantageous for genetic diversity and producing progeny with unique genes that may be beneficial in evolution. For agriculture, this method is preferential for selection of desirable traits in crops when cross breeding. CMS is typically caused by genes in the mitochondrial DNA (mtDNA), such as novel open reading frames (ORFs) that form after imperfect repair of double-stranded breaks in the mtDNA. Specific CMS genes vary among various plant species. It …

Genome-Wide Identification Of Wrky Transcription Factor Encoding Genes In Amborella Trichopoda Baill. (Amborellaceae), Bijaya Pradhan

Electronic Theses and Dissertations

WRKY transcription factors (TFs) are DNA-binding proteins, which play important roles in managing plant stresses and regulating growth and development processes. The WRKY TF family has expanded significantly through genome/gene duplications in the plant evolutionary process. Although the WRKY TFs have been identified in hundreds of plant species, they are yet to be identified in Amborella trichopoda, a species that represents the most basal group of Angiosperms. The main objectives of this study were to conduct genome-wide identification of the WRKY gene family in A. trichopoda and to assess their homologs in Angiosperms. In this study, we identified …

E. Coli Persister Cell Survival And Rhizobia Attachment To Soybean Roots, Tanim Islam

Electronic Theses and Dissertations

The theme of this thesis revolves around how bacteria respond and thrive during stress. Chapters 1-3 are about how bacteria deal with life-threatening antibiotics. Chapter 4 covers new research on how bacteria can move from a stressful individual lifestyle (free-living bacteria) to initiating a symbiotic relationship with a plant (a less stressful lifestyle). In Chapter 1, I briefly summarize the current state of knowledge in the field of antibiotic resistance and persistence. In Chapter 2, I add to this knowledge by providing new insights into several antibiotics' potency and exploring the antibiotic Eagle effect. In Chapter 3, I use pyruvate …

The Role Of Nitric Oxide In Inter- And Intra- Cellular Signaling In Plant Defense, Fan Xia

Theses and Dissertations--Plant Pathology

Plants have evolved a sophisticated immune system to defend themselves against pathogens. This immune response can be triggered in response to pathogen-associated molecular patterns (PAMP) or specialized effectors that are recognized by the plant resistance (R) proteins. The latter, commonly referred to as effector-triggered immunity (ETI), is well known to induce broad-spectrum resistance throughout the plants. This phenomenon known as systemic acquired resistance (SAR) is regulated by several chemical signals including salicylic acid (SA), and free radical nitric oxide (NO) and reactive oxygen species (ROS). These signals operate in two parallel branches with NO/ROS functioning downstream of pipecolic acid (Pip) …

Callery Pear Removal Experiment: Trees-Intact (Medlar Conservation Area), Margaret E. Maloney, Eric B. Borth, Grace Dietsch, Mary C. Lloyd, Ryan W. Mcewan

Five Rivers MetroParks Collaboration Data Archive

The invasive tree Callery pear (Pyrus calleryana) is problematic in open habitats in the American Midwest. We investigated the efficacy of various control techniques on P. calleryana invasion in grasslands. Treatments were applied to P. calleryana stems that were single-stemmed trees (around 7 years; n = 40 stems), and response of those stems was measured.

Callery Pear Removal Experiment: Trees-Sprouting (Stillwater Conservation Area), Margaret E. Maloney, Eric B. Borth, Grace Dietsch, Mary C. Lloyd, Ryan W. Mcewan

Five Rivers MetroParks Collaboration Data Archive

The invasive tree Callery pear (Pyrus calleryana) is problematic in open habitats in the American Midwest. We investigated the efficacy of various control techniques on P. calleryana invasion in grasslands. Treatments were applied to P. calleryana stems that had experienced mowing annually for several years and were sprouting (n = 100 stems) and response of those stems was measured.

Geospatial Data Permanent Plot, Grace K. Attea, Ryan W. Mcewan, John L. Vankat

Data Files for Old-Growth Deciduous Forest Dynamics Archive: Hueston Woods

Permanent plot GIS shapefile that measures 100m x 105m and consists of 420 contiguous 5m x 5m subplots. There are 21 transects that run from south to north and 20 subplots per transect that run east to west. This downloadable data is a zipped file containing 8 shapefile building blocks. Geographic Coordinate System: GCS_North_American_1983. Projected Coordinate System: NAD_1983_StatePlane_Ohio_South_FIPS_3402 (meters).

Field Maps 2022, Grace K. Attea, Ryan W. Mcewan, John L. Vankat

Data Files for Old-Growth Deciduous Forest Dynamics Archive: Hueston Woods

Historical field map scans (2022) for the permanent 100m x 105m research plot in Hueston Woods State Nature Preserve.

Geospatial Data Trees 1994, Grace K. Attea, Ryan W. Mcewan, John L. Vankat

Data Files for Old-Growth Deciduous Forest Dynamics Archive: Hueston Woods

Location and demographic data collected for each individual tree in 1994 in Hueston Woods State Nature Preserve. These maps were digitized from the historical field maps to a GIS shapefile for each sampling year. Geographic Coordinate System: GCS_North_American_1983. Projected Coordinate System: NAD_1983_StatePlane_Ohio_South_FIPS_3402 (meters).

Geospatial Data Trees 2000, Grace K. Attea, Ryan W. Mcewan, John L. Vankat

Data Files for Old-Growth Deciduous Forest Dynamics Archive: Hueston Woods

Location and demographic data collected for each individual tree in 2000 in Hueston Woods State Nature Preserve. These maps were digitized from the historical field maps to a GIS shapefile for each sampling year. Geographic Coordinate System: GCS_North_American_1983. Projected Coordinate System: NAD_1983_StatePlane_Ohio_South_FIPS_3402 (meters).

Geospatial Data Trees 2022, Grace K. Attea, Ryan W. Mcewan, John L. Vankat

Data Files for Old-Growth Deciduous Forest Dynamics Archive: Hueston Woods

Location and demographic data collected for each individual tree in 2022 in Hueston Woods State Nature Preserve. These maps were digitized to a GIS shapefile for each sampling year. Geographic Coordinate System: GCS_North_American_1983. Projected Coordinate System: NAD_1983_StatePlane_Ohio_South_FIPS_3402 (meters).

Geospatial Data Trees 1988, Grace K. Attea, Ryan W. Mcewan, John L. Vankat

Data Files for Old-Growth Deciduous Forest Dynamics Archive: Hueston Woods

Location and demographic data collected for each individual tree in 1988 in Hueston Woods State Nature Preserve. These maps were digitized from the historical field maps to a GIS shapefile for each sampling year. Geographic Coordinate System: GCS_North_American_1983. Projected Coordinate System: NAD_1983_StatePlane_Ohio_South_FIPS_3402 (meters).

Garlic Curing: Post-Harvest Nutrient Remobilization From Leaves To Cloves, Mary L. Books

Graduate Theses/Dissertations

Garlic (Allium sativum L.) is grown on small and large scales worldwide. After harvesting, garlic undergoes a drying process for long-term preservation, called curing. Some producers cure with leaves intact, while others will remove and discard the leaves, curing only the bulbs. Due to the ability of plants to remobilize nutrients from leaves to underground storage organs, such as bulbs, the curing method of garlic may affect clove nutrient content. This study explores nutrient remobilization responses in garlic when cured with leaves intact compared to leaves separated from bulbs. Four cultivars of garlic, German White, Chesnok Red, Romanian Red, and …

Analysis Of Root System Architecture And Qtl Identification In Grapevines, Sujan Thapa

Graduate Theses/Dissertations

The root system of the plant plays a vital role in water and nutrient uptake. Native North American grapevines adapted to a broad range of climatic and soil conditions, which led to the evolution of diverse root system architecture (RSA) within the Vitis genus. Despite the importance of RSA in viticulture, little is known about the genetic basis of the RSA in grapevine. I used novel root phenotyping tool, RhizoVision Analyzer to characterize the root system of 208 genotypes of an F₁ grapevine progeny obtained from a cross between Vitis rupestris Scheele B38 and Vitis riparia Michx. HP-1. Dormant …

Common Garden Study Reveals Frost-Tolerant, Generalist Northern Seed Sources Are Best Suited To Expand Range Of Quercus Rubra, Emily Lindback

Dissertations, Master's Theses and Master's Reports

Climate change is shifting the potential suitable range of northern red oak (Quercus rubra L.) faster than it can migrate, creating an adaptation lag. Quercus rubra is prominent in eastern North American forests and important for its carbon sequestration, ecological roles, and economic significance. Our study addresses which populations of Q. rubra are best suited for climatic conditions at the northern and central range limits. Our findings can inform forestry management policies such as assisted migration, where species are transferred within their native range to mitigate the effects of climate change. We planted over 800 Q. rubra seedlings …

Field Validation Of A Farmer Supplied Data Approach To Close Soybean Yield Gaps In The Us North Central Region, José F. Andrade, Spyridon Mourtzinis, Juan I. Rattalino Edreira, Shawn P. Conley, John Gaska, Herman J. Kandel, Laura E. Lindsey, Seth Naeve, Scott Nelson, Maninder P. Singhi, Laura J. Thompson, James E. Specht, Patricio Grassini

Department of Agronomy and Horticulture: Faculty Publications

CONTEXT: Producer-reported data can be used to identify suites of management practices that lead to higher yield and profit. However, a rigorous validation of the approach in relation to its potential impact on farmer yield and profit is lacking.

OBJECTIVE: This study aimed to validate a producer-data approach on its capability to guide on-farm evaluation of management practices with greatest potential for increasing producer yield and profit. We show proof of concept using soybean in the North Central US region as a case study.

METHODS: We used a combination of regression tree analysis and a spatial framework to determine practices …

A New Perspective When Examining Maize Fertilizer Nitrogen Use Efficiency, Incrementally, Newell R. Kitchen, Curtis J. Ransom, James S. Schepers, Jerry L. Hatfield, Raymond Massey, Scott T. Drummond

Department of Agronomy and Horticulture: Faculty Publications

For maize (Zea mays L.), nitrogen (N) fertilizer use is often summarized from field to global scales using average N use efficiency (NUE). But expressing NUE as averages is misleading because grain increase to added N diminishes near optimal yield. Thus, environmental risks increase as economic benefits decrease. Here, we use empirical datasets obtained in North America of maize grain yield response to N fertilizer (n = 189) to create and interpret incremental NUE (iNUE), or the change in NUE with change in N fertilization. We show for those last units of N applied to reach economic optimal N …

Inactivation Of The Entire Arabidopsis Group Ii Gh3s Confers Tolerance To Salinity And Water Deficit, Rubén Casanova-Sáez, Eduardo Mateo-Bonmatí, Jan Šimura, Aleš Pěnčík, Ondřej Novák, Paul Staswick, Karin Ljung

Department of Agronomy and Horticulture: Faculty Publications

Indole-3-acetic acid (IAA) controls a plethora of developmental processes. Thus, regulation of its concentration is of great relevance for plant performance. Cellular IAA concentration depends on its transport, biosynthesis and the various pathways for IAA inactivation, including oxidation and conjugation.

Group II members of the GRETCHEN HAGEN 3 (GH3) gene family code for acyl acid amido synthetases catalysing the conjugation of IAA to amino acids. However, the high degree of functional redundancy among them has hampered thorough analysis of their roles in plant development.

In this work, we generated an Arabidopsis gh3.1,2,3,4,5,6,9,17 (gh3oct) mutant to knock out the group II …

Root Exudates Impact Plant Performance Under Abiotic Stress, Yen Ning Chai, Daniel P. Schachtman

Department of Agronomy and Horticulture: Faculty Publications

Plant root exudates serve pivotal roles in supporting plant development and interactions with the physicochemical and biological factors in the rhizosphere. Under stress conditions, root exudation is involved in enhancing plant resource-use efficiency and facilitating the crosstalk between plant and soil microbes to ameliorate stress. Although there are a large number of root exudates that remain to be characterized, recent technological advancements have allowed for the function of many exudate compounds to be elucidated. In this review, we discuss current knowledge about the key root exudates that modulate plant resource-use efficiency under various abiotic stresses including drought, aluminum toxicity, phosphorus, …