Plant Sciences Commons^™

Investigating Birds As Dispersal Vectors Of Litylenchus Crenatae Subsp. Mccannii (Anguinidae), The Nematode Associated With Beech Leaf Disease, Spencer Rock Parkinson

Graduate Theses, Dissertations, and Problem Reports

Beech leaf disease (BLD) is an emerging forest pathogen primarily affecting American beech (Fagus grandifolia, Ehrh.) in North America and has been attributed to tree mortality of sapling sized trees within five to seven years of infection. Symptoms typically occur in regenerating American beech thickets sprouting from roots of trees killed by beech bark disease. Scientists first observed BLD in Ohio in 2012 and currently has spread to 15 states in the USA and one Canadian province. The nematode Litylenchus crenatae subsp. mccannii (Lcm) is highly associated with BLD symptoms, interveinal chlorosis and defoliation of leaves, and is currently …

Investigation Of Fungal Pathogens And Woodboring Beetles Of Sugarbush Stands In The Central Appalachian Region, Molly A. Sherlock

Graduate Theses, Dissertations, and Problem Reports

The production of maple syrup is a valuable source of income and cultural identity for many rural communities throughout the central Appalachian region. Regardless, maple syrup producers face difficulties maintaining the health and productivity
of their stands due to various impacts of climate change, which have given rise to extreme weather events that exacerbate damage caused by pests and diseases. To ensure the long-term sustainability of the maple syrup industry, it is crucial to obtain a comprehensive understanding of the current biotic threats within the region, particularly woodboring insects and fungal pathogens. However, insufficient information exists regarding the community assemblages …

Forage Grass Growth Habit And Allelopathy In Birdsfoot Trefoil Germination And Establishment, Nathan El Blake

Graduate Theses, Dissertations, and Problem Reports

Birdsfoot trefoil (Lotus corniculatus L.) (BFT) is a high quality, tanniniferous forage legume that has been shown to mitigate gastrointestinal nematode (GIN) infection in sheep. Reliable establishment of birdsfoot trefoil in existing pastures is difficult due to BFT’s poor seedling vigor, susceptibility to crown and root rot, and, perhaps chiefly, competition from other pasture plants. Most existing pastures in the Northeastern United States are primarily composed of cool-season grasses, many of which can be highly competitive. A common form of interplant competition is allelopathy, which occurs when secondary metabolites produced by a plant inhibit a necessary growth process of …

Revisiting The Dual Pathway Hypothesis Of Chorismate Production In Plants, Joseph H. Lynch

Faculty & Staff Scholarship

The shikimate pathway, the seven enzymatic steps that synthesize chorismate from phosphoenolpyruvate and erythrose 4-phosphate, produces the last common precursor of the three aromatic amino acids. It is firmly established that all seven enzymes are present in plastids, and it is generally accepted that this organelle is likely the sole location for production of chorismate in plants. However, recently a growing body of evidence has provided support for a previous proposal that at least portions of the pathway are duplicated in the cytosol, referred to as the Dual Pathway Hypothesis. Here I revisit this obscure hypothesis by reviewing the findings …

Identification Of Sesquiterpenes In Wild Tomato Accessions With Activities Against The Potato Aphid And Their Tissue-Specific Engineering In Cultivated Tomato, Fumin Wang

Graduate Theses, Dissertations, and Problem Reports

The potato aphid (Macrosiphum euphorbiae Thomas) poses a serious problem in the commercial production of horticultural crops including tomato, since it causes damage by stylet feeding and the transmission of viruses for which it serves as the vector. Application of conventional pesticides being the fundamental tactic in the control of the aphid is increasingly considered insufficient and problematic due to emerging pest resistances and biosafety issues, highlighting the continuing need to develop new efficient and sustainable approaches. Alternatively, glandular trichomes of plants are well-known epidermal hairy tissues producing various secondary metabolites that involve in plant-insect interactions, while the terpene …

Getting To The Root Cause: The Genetic Underpinnings Of Root System Architecture And Rhizodeposition In Sorghum, Farren Smith

Graduate Theses, Dissertations, and Problem Reports

Plants are some of the most diverse organisms on earth, consisting of more than 350,000 different species. To understand the underlying processes that contributed to plant diversification, it is fundamental to identify the genetic and genomic components that facilitated various adaptations over evolutionary history. Most studies to date have focused on the underlying controls of above-ground traits such as grain and vegetation; however, little is known about the “hidden half” of plants. Root systems comprise half of the total plant structure and provide vital functions such as anchorage, resource acquisition, and storage of energy reserves. The execution of these key …

Phenomic And Genetic Controls Of The Drought Stress Response In Sorghum, Melissa A. Lehrer

Graduate Theses, Dissertations, and Problem Reports

Drought, one of the most common abiotic stressors, is a result of the precipitation and temperature fluctuations influenced by climate change. As consistent weather patterns are crucial for the maintenance of crop yield, drought threatens food security through its impact on plant growth and development. It is essential to ensure the quality, availability, and affordability of grain-based products in the face of climate change due to expectations of population growth. Therefore, shedding light on the mechanisms associated with drought tolerance is integral to maintaining agricultural production under water-limited conditions. My dissertation work aimed to uncover the morphological, physiological, and genetic …

The Impacts Of Maple Syrup Production On The Herbaceous Layer In Appalachian Hardwood Forests, Logan Scott Ferguson

Graduate Theses, Dissertations, and Problem Reports

Vegetation data were collected from eight maple syrup farms (sugarbushes) and eight undeveloped maple-dominated sites to examine potential differences in understory plant communities due to disturbance effects. Understory plants were identified to the species level and percent cover of aboveground leaf-area for each species was estimated within 600 total quadrats. Overstory data and environmental data were collected to help determine if they had any effect on herbaceous-layer plant communities. Species richness, Shannon diversity, and Pielou’s evenness were calculated, with the analysis showing no significant differences between the site types. The absolute cover of plant functional groups was also compared between …

Soil Response Of Helicopter Liming In The Monongahela National Forest, Jarrett Douglas Fowler

Graduate Theses, Dissertations, and Problem Reports

Soils in the Monongahela National Forest (MNF) are acidic due to sandstone parent material, acid deposition, uptake of base cations by vegetation, and release of organic acids by organic matter (OM) decomposition. Increases in soil acidity have caused declines in forest health and changed species composition and nutrient status. Liming can neutralize soil acidity, but no large-scale liming projects have been done on acid forest soils in the USA. In anticipation of acquiring funding for a proposed liming project in the MNF, in 2007 and 2009 10 sites were selected to sample and analyze soils before lime was applied. In …

Biofortification Of Sodium Selenate Improves Dietary Mineral Contents And Antioxidant Capacity Of Culinary Herb Microgreens, Rachel Newman G. Newman, Youyoun Moon, Carl E. Sams, Janet C. Tou, Nicole L. Waterland

Faculty & Staff Scholarship

Selenium biofortification of plants has been suggested as a method of enhancing dietary seleniumintake to prevent deficiency and chronic disease in humans, while avoiding toxic levels of intake. Popular herbs such as basil (Ocimum basilicum L.), cilantro (Coriandrum sativum L.), and scallions (Allium fistulosum L.) present an opportunity for biofortification as these plants are used for added flavors to meals and are available as microgreens, young plants with increasing popularity in the consumer marketplace. In this study, basil, cilantro, and scallion microgreens were biofortified with sodium selenate under hydroponic conditions at various selenium concentrations to investigate the effects on yield, …

Evaluation Of Calcium Application Methods On Delaying Plant Wilting Under Water Deficit In Bedding Plants, Suejin Park, Nicole L. Waterland

Faculty & Staff Scholarship

Floriculture crops can lose their aesthetic quality due to water deficit during postproduction. Calcium is a secondary messenger in plant stress signaling, and the treatment of calcium has been proposed to alleviate damage by various abiotic stresses. The objective of this research was to evaluate application methods of calcium to delay plant wilting under water deficiency in three species of bedding plants: viola (Viola cornuta), impatiens (Impatiens walleriana), and petunia (Petunia grandiflora). Three application methods were compared including spray, drench, and pre-drench. Calcium was applied as CaCl₂ and Ca(NO₃)₂ at three concentrations ranging from 50 to …

Plant Species Identification In The Wild Based On Images Of Organs, Meghana Kovur

Graduate Theses, Dissertations, and Problem Reports

Image-based plant species identification in the wild is a difficult problem for several reasons. First, the input data is subject to a very high degree of variability because it is captured under fully unconstrained conditions. The same plant species may look very different in different images, while different species can often appear very similar, challenging even the recognition skills of human experts in the field. The large intra-class and small inter-class image variability makes this a fine-grained visual classification problem. One way to cope with this variability and to reduce image background noise is to predict species based on the …

Traditional And Modern Breeding Strategies Towards Developing Resilient Crops: Two Case Studies In Tomato, Estefania Tavares Flores

Graduate Theses, Dissertations, and Problem Reports

Crop designing for resilience traits to produce satisfactorily under adverse conditions and scenarios is a priority for the future of global food security. In this thesis, two different approaches addressing major stress factors for tomato cropping are presented. We first aimed to domesticate tomato de novo as a high-salinity resistant crop using the wild relative, S. cheesmaniae via gene editing. We conducted single-gene and multiplex knock-out strategies using CRISPR/Cas9 genome editing to create loss-of-function alleles for the domestication-related genes BIF, CycB, J2, EJ2, MULTI, SP, SP5G, and FW11.3 in order to create a novel, halophyte tomato harboring an inherent high-salinity …

Environmental Controls On The Terrestrial Water Cycle In Forested Mountain Ecosystems., Luis Andrés Guillén

Graduate Theses, Dissertations, and Problem Reports

Water is a key resource to natural ecosystems and human societies alike, and the water cycle is fundamentally linked to the climate and the characteristics of catchments. However, the challenges posed by environmental change makes it imperative to understand how the water cycle is affected by biotic and abiotic factors, in particular, in areas that are crucial sources of water like forested headwater catchments. Therefore, this doctoral dissertation aims to advance the knowledge on the dynamics between climate, vegetation and landscape that determine the water balance of forested mountain ecosystems. This document presents five chapters, an introductory chapter, three standalone …

Treatment With Calcium Chloride Enhances Water Deficit Stress Tolerance In Viola (Viola Cornuta), Suejin Park, Youyoun Moon, Nicole L. Waterland

Faculty & Staff Scholarship

Water deficit stress can reduce the postproduction shelf life and marketability of floriculture crops. To alleviate the damage by water deficiency, plants need to limit transpirational water loss by inducing stomatal closure. Osmotic stress induces stomatal closure like the response to water deficit stress. It could be used as a convenient tool to enhance water deficit stress tolerance by reducing water loss. The objective of this research was to investigate whether osmotic treatment with a high concentration of chemical solutions could trigger a response to osmotic stress so that stomatal closure can be induced, resulting in enhanced water deficit stress …

Occurrence, Mating Strategy, And Pathogenicity Of Members Of Nectriaceae In Central Appalachia, Cameron Michael Stauder

Graduate Theses, Dissertations, and Problem Reports

Members of the Nectriaceae occupy many ecological niches including dominant canker pathogens, such as Neonectria ditissima and N. faginata. These two pathogens contribute to the decline of American beech (Fagus grandifolia) forests across the Appalachian Mountains due to beech bark disease (BBD). Interestingly, N. ditissima represents a well-known canker pathogen many hardwood species, while N. faginata has not been observed outside of BBD. Additionally, N. faginata occurs at higher incidences than N. ditissima in BBD stands. Nectriaceae in Central Appalachia were surveyed as to further characterize the diversity and possibly identify a non-beech host of N. faginata. …

Evolutionary Genomics Of Dynamic Sex Chromosomes In The Salicaceae, Ran Zhou

Graduate Theses, Dissertations, and Problem Reports

Identifying the sex-determination region (SDR) and other genomic features of sex chromosomes are of great importance in the studies of the evolution of sex. However, the process of accurately identifying the size and location of the SDR is often difficult, even when a genomic sequence is available. This usually is hindered by large repetitive elements and a lack of recombination in the SDR. In this thesis, I assemble sex chromosomes with whole genomic sequencing data, identify SDRs and explore their genomic features in two sister species from the Salicaceae family. I also develop an interpretation of the lability of the …

Comparing And Linking Organic Carbon And Iron In Soil And Headwater Stream In A Pasture And A Forest Catchment In A Central Appalachian Region, West Virginia, Lili Lei

Graduate Theses, Dissertations, and Problem Reports

Continued global warming and surface water brownification are two main environmental issues which have attracted attention and are related to soil organic carbon (SOC) cycling. Iron oxides differ in reducibility and thus have essential roles in regulating SOC preservation and remineralization in soil and transport of dissolved organic carbon (DOC) from soil to surface water. In the central Appalachian region, anthropogenic disturbances are increasing, which leads to major issues of soil degradation and depletion of SOC concentrations. Cropland and pasture soils are subject to intense disturbances compared to the forest soil, which may lead to differences in SOC fractions and …

Trees, Fungi, Insects: How Host Plant Genetics Builds A Community, Sandra Jeanne Simon

Graduate Theses, Dissertations, and Problem Reports

Organisms, such as fungi and insects, can cause millions of acres of agricultural and forest damage, while others provide billions of dollars in ecological services such as education, aesthetic enjoyment, pollination, and gardening. Plant breeding and biotechnology can potentially help establish a balance between the proliferation of detrimental pests and attraction of beneficial insects. Variation in plant physiological and morphological characteristics are extremely important in the ability of host tissues to support many different types of organisms. When that variation is genetically heritable in a plant population, shifts in the underlying genes can have predictable consequences in structuring entire ecosystems. …

Improving The Biological Control Of Persicaria Perfoliata (Polygonaceae) Using Rhinoncomimus Latipes Korotyaev (Coleoptera: Curculionidae), Jaewon Kim

Graduate Theses, Dissertations, and Problem Reports

Persicaria perfoliata (L.) H. Gross (Polygonaceae; Mile-a-minute weed) is a rapid-growing invasive vine introduced from eastern Asia to northeastern United States in the 1930s. This vine has been invaded in disturbed areas and reforestation sites in 15 states in the U.S. and forms dense, monocultural patches that may inhibit natural forest regeneration. To control this weed, a host-specific biocontrol agent, Rhinoncomimus latipes Korotyaev (Coleoptera: Curculionidae) has been released in the P. perfoliata invaded states in the U.S. during the past 15 years. Currently, R. latipes is released by hand to the invaded area where the presence of the weed is …

Genetic And Biochemical Characterization Of Ergot Alkaloid Synthesizing Fungi And Their Symbionts, Matthew Duane Maust

Graduate Theses, Dissertations, and Problem Reports

Ergot alkaloids are fungal tryptophan derived toxins which affect mammalian circulation and neurotransmission. These compounds are biosynthesized by a conserved genetic pathway, known as the ergot alkaloid synthesis (EAS) pathway by fungi belonging to the ascomycete families Trichocomaceae and Clavicipitaceae. Several Ipomoea species and related plants in the morning glory family harbor vertically transmitted symbiotic fungi in the genus Periglandula, also members of Clavicipitaceae, that produce ergot alkaloids. Metabolomic analysis of seeds identified a previously uncharacterized glycoside form of the pharmaceutically important ergot alkaloid, ergonovine. Several species belonging to the fungal genus Metarhizium have recently been shown to have the …

The Morphological, Physiological, And Genetic Underpinnings Of Intraspecific Salinity Tolerance In Sorghum Bicolor, Ashley N. Henderson

Graduate Theses, Dissertations, and Problem Reports

Decreases in land quality and quantity threaten the efficient production of agriculturally and economically pivotal crops. Such reductions in arable lands are a consequence of population growth and urbanization, and often result in the introduction of various abiotic stresses. The most common abiotic stressors include water limitation (drought), water logging (over watering), poor water quality (salinity), and extreme temperatures (cold, frost, heat). Each of these stressors negatively impact plant growth, development, and yield. Soil salinity, specifically, is a considerable constraint affecting lands used in agriculture. Salts in the soil rise both naturally and through anthropogenic factors making the abundance a …

Alternative Media And Mulches In Organic Vegetable Production, Heather R. Griffith

Graduate Theses, Dissertations, and Problem Reports

Reducing or eliminating waste from organic vegetable production can conserve money as well as resources. Conventional greenhouse production of vegetable transplants often relies on abundant fertigation which produces large amounts of polluted runoff, and the field production of organic vegetables frequently relies on the use of polyethylene mulch. A greenhouse study was conducted to determine if organic transplants can be successfully produced in a greenhouse under reduced soil moisture in order to reduce leaching of nutrients and potential water pollution. To test this, we compared the effect of reduced irrigation volumes to the standard practice of irrigating with 120% of …

The Nac Family Transcription Factor Gmnac42–1 Regulates Biosynthesis Of The Anticancer And Neuroprotective Glyceollins In Soybean, Md Asraful Jahan, Brianna Harris, Matthew Lowery, Katie Coburn, Aniello M. Infante, Ryan J. Percifield, Amanda G. Ammer, Nik Kovinich

Faculty & Staff Scholarship

Background

Glyceollins are isoflavonoid-derived pathogen-inducible defense metabolites (phytoalexins) from soybean (Glycine max L. Merr) that have important roles in providing defense against pathogens. They also have impressive anticancer and neuroprotective activities in mammals. Despite their potential usefulness as therapeutics, glyceollins are not economical to synthesize and are biosynthesized only transiently and in low amounts in response to specific stresses. Engineering the regulation of glyceollin biosynthesis may be a promising approach to enhance their bioproduction, yet the transcription factors (TFs) that regulate their biosynthesis have remained elusive. To address this, we first aimed to identify novel abiotic stresses that enhance …

Early Tree Growth In Reclaimed Mine Soils In Appalachia Usa, Kara Dallaire, Jefferey Skousen

Faculty & Staff Scholarship

Abstract: Surface mining disturbs hundreds of hectares of land every year in many areas of the world, thereby altering valuable, ecologically-diverse forests. Reforestation of these areas after mining helps to restore ecosystem functions and land value. In Appalachia, native topsoil is normally replaced on the surface during reclamation, but waivers allow for brown and gray sandstone materials to be used as topsoil substitutes. Numerous studies report the growth of trees in these substitute mine soil materials, but few studies have compared the height of trees grown in reclaimed mine soils to the heights of trees grown in native soils. This …

Integrated Pest Management Of Longan (Sapindales: Sapindaceae) In Vietnam, Hanh Tran, Hoa Nguyen Van, Rangaswamy Muniappan, James Amrine, Rayapati Naidu, Robert Cilbertson, Jaspreet Sidhu

Faculty & Staff Scholarship

This paper describes the current state of pests and diseases of longan (Dimocarpus longan Lour.) and their management in Vietnam. Longan is the third most cultivated fruit crop and second major fruit crop exported from Vietnam. Brief descriptions of arthropod pests Eriophyes dimocarpi Kuang (Acari: Eriophyidae), Conogethes punctiferalis Guenée (Lepidoptera: Crambidae), Conopomorpha sinensis Bradley (Lepidoptera: Gracillariidae), Conopomorpha litchiella Bradley (Lepidoptera: Gracillariidae), Tessaratoma papillosa Drury (Hemiptera: Tessaratomidae), Eudocima phalonia L. comb. (Lepidoptera: Erebidae), oriental fruit fly Bactrocera dorsalis Hendel (Diptera: Tephretidae), Planococcus lilacinus Cockerell (Hemiptera: Pseudococcidae), Drepanococcus chiton Green (Hemiptera: Coccidae), and Cornegenapsylla sinica Yang & Li (Hemiptera: Psyllidae) and fungal …

Effects Of 1-Mcp On Quality And Storability Of Cherry Tomato (Solanum Lycopersicum L.), Adanech Melaku Taye, Shimeles Tilahun, Mu Hong Seo, Do Su Park, Cheon Soon Jeong

Faculty & Staff Scholarship

Cherry tomato is a perishable fruit due to its high rate of ethylene production and respiration during ripening. 1-Methylcyclopropene (1-MCP) is known to control ripening and reduce decay of fruit by inhibiting ethylene action. In the present study, the influence of 1-MCP application on quality and storability of ‘Unicorn’ cherry tomato was observed. Fruit at pink and red maturity stages were put in the commercial plastic containers and sealed with 40 μm low density polyethylene (LDPE) film, treated with 1-MCP (0 µL L−1 (control), 0.035 µL L−1 and 0.1 µL L−1), and stored at 10 °C in 85 ± 5% …

Portable X-Ray Fluorescence Spectroscopy For Rapid And Cost-Effective Determination Of Elemental Composition Of Ground Forage, Yadav Sapkota, Louis M. Mcdonald, Thomas C. Griggs, Thomas J. Basden, Brandon Lee Drake

Faculty & Staff Scholarship

The recent development of portable X-ray fluorescence spectrometers (PXRF) has created new avenues for rapid plant elemental concentration determination at reduced cost while avoiding hazardous chemicals. A few studies have indicated the potential use of PXRF for homogenous plant tissue analysis. However, there is a lack of information for analysis of heterogeneous plant samples like livestock forage, which consists of a mixture of several species and plant parts, each varying in elemental concentration. Our objective was to evaluate PXRF for forage analysis, specifically the effect of forage particle size and scan time on important elements including P, K, Ca, and …

Morphological And Phylogenetic Resolution Of Diplodia Spp., Emerging Canker Pathogens Of Oak (Quercus Spp.), In The United States, Savannah Lyn Ferreira

Graduate Theses, Dissertations, and Problem Reports

In Mediterranean Europe and the United States, oak species (Quercus spp.) have been in a state of declining health and vigor for the past several decades. Several biotic agents have been found to contribute to this decline to varying degrees including Phytophthora cinnamomi and Armillaria spp., both causal agents of root rots, and various insect defoliators. In the U.S., Bretziella fagacearum, the causal agent of oak wilt, has also been implicated. More recently, Diplodia corticola (Dc) and other Diplodia spp. have been implicated in causing dieback and mortality of oak species in Europe and in …

Enhancing Water Stress Tolerance In Floriculture Crops, Suejin Park

Graduate Theses, Dissertations, and Problem Reports

Water deficit is one of the major constraints on plant growth and development, causing reduction of crop productivity. To minimize water loss, among many adaptation strategies, plants close their stomata to reduce transpiration. The stomatal closure is regulated by light, internal CO2 concentration, and plant hormones, mainly abscisic acid. Plants’ response mechanisms to water deficit are complex processes involving numerous genes and various signaling pathways. Floriculture crops are often exposed to water deficit during shipping and retailing, and these periods often result in damaged crops and profit loss. Understanding of plant responses to water deficit stress will provide us an …