Plant Biology Commons^™

Edaphic, Microtopographic, And Light Characteristics Associated With The Endangered Running Buffalo Clover (Trifolium Stoloniferm) At The Blue Grass Army Depot, Madison County, Kentucky, Lance Austin Watt

Online Theses and Dissertations

Soil, microtopographic, and light parameters associated with federally endangered running buffalo clover (Trifolium stoloniferum) plants on the Blue Grass Army Depot, Richmond, KY, were examined during the 2004 and 2005 growing season. Study samples or measurements were determined at 27 "long-term" sites (plots which have had clover present since 1992-1994), 23 "disappeared" sites (plots which had clover in 1992-1994, but did not have plants present at the time of this study) and 25 random/control sites (randomly selected 1 m2 plots in areas in which running buffalo clover has never been reported).

Average precipitation on the Blue Grass Army Depot was …

Heterogeneous Stress Response In A Clonal Invader (Imperata Cylindrica): Implications For Management, Sarah Grace Sanford

USF Tampa Graduate Theses and Dissertations

Life history traits such as growth, survival, and clonality can vary within a population. When such variation exists in a population of an invasive species, it can affect population dynamics, and if any part of the variation has a genetic basis the population can evolve in response to control regimes. Evolutionary responses to control efforts may shift the population towards a few more resilient genotypes, or towards different types in different microenvironments, depending on the scale of gene flow with respect to the patchiness of the environment. The purpose of this study is to examine whether the application of stress …

Switchgrass, Kenneth P. Vogel, Gautam Sarath, Aaron J. Saathoff, Robert B. Mitchell

Department of Agronomy and Horticulture: Faculty Publications

17.1 Introduction

Switchgrass (Panicum virgatum L.) is a warm-season perennial grass that is native to North America that is being developed into a biomass energy crop. It has been used in pastures and for conservation purposes in the Great Plains and the Midwest, USA, for over 70 years.1 The research supporting its use as a pasture and conservation species was largely conducted by US Department of Agriculture (USDA) research programs, most notably the Agricultural Research Service (ARS) project located at the University of Nebraska-Lincoln and USDA Plant Materials Centers that are located throughout the United States. In this report, …

Identification Of A Second Asian Soybean Rust Resistance Gene In Hyuuga Soybean, Mandy D. Kendrick, Donna K. Harris, Bo-Keun Ha, D. L. Hyten, P. B. Cregan, Reid D. Frederick, H. Roger Boerma, Kerry F. Pedley

Department of Agronomy and Horticulture: Faculty Publications

Asian soybean rust (ASR) is an economically significant disease caused by the fungus Phakopsora pachyrhizi. The soybean genes Rpp3 and Rpp?(Hyuuga) confer resistance to specific isolates of the pathogen. Both genes map to chromosome 6 (Gm06) (linkage group [LG] C2). We recently identified 12 additional soybean accessions that harbor ASR resistance mapping to Gm06, within 5 centimorgans of Rpp3 and Rpp?(Hyuuga). To further characterize genotypes with resistance on Gm06, we used a set of eight P. pachyrhizi isolates collected from geographically diverse areas to inoculate plants and evaluate them for differential phenotypic responses. …

Mutational Analysis Of The Major Soybean Uref Paralogue Involved In Urease Activation, Joe C. Polacco, D. L. Hyten, Mônica Medeiros-Silva, David A. Sleper, Kristin D. Bilyeu

Department of Agronomy and Horticulture: Faculty Publications

The soybean genome duplicated ~14 and 45 million years ago and has many paralogous genes, including those in urease activation (emplacement of Ni and CO₂ in the active site). Activation requires the UreD and UreF proteins, each encoded by two paralogues. UreG, a third essential activation protein, is encoded by the single-copy Eu3, and eu3 mutants lack activity of both urease isozymes. eu2 has the same urease-negative phenotype, consistent with Eu2 being a single-copy gene, possibly encoding a Ni carrier. Unexpectedly, two eu2 alleles co-segregated with missense mutations in the chromosome 2 UreF paralogue (Ch02UreF), suggesting …

Cytokinin-Mediated Source ⁄Sink Modifications Improve Drought Tolerance And Increase Grain Yield In Rice Under Water-Stress, Zvi Peleg, Maria Reguera, Ellen Tumimbang, Harkamal Walia, Eduardo Blumwald

Department of Agronomy and Horticulture: Faculty Publications

Drought is the major environmental factor limiting crop productivity worldwide. We hypothesized that it is possible to enhance drought tolerance by delaying stress-induced senescence through the stress-induced synthesis of cytokinins in crop-plants. We generated transgenic rice (Oryza sativa) plants expressing an isopentenyltransferase (IPT) gene driven by PSARK, a stress- and maturation-induced promoter. Plants were tested for drought tolerance at two yield-sensitive developmental stages: pre- and post-anthesis. Under both treatments, the transgenic rice plants exhibited delayed response to stress with significantly higher grain yield (GY) when compared to wild-type plants. Gene expression analysis revealed a significant shift in expression of hormone-associated …

Cloning, Expression Analysis, And Transformation Vector Construction Of Dam Homologs In Peach And Poplar, Yuhui Xie

All Theses

Genetic fine mapping and sequencing of the EVG locus in peach [Prunus persica (L.) Batsch] identified six tandem arrayed Dormancy-Associated MADS-box (DAM) genes as candidates for regulating growth cessation and terminal bud formation in the non-dormant evergrowing (evg) mutant. Since the mutant is lacking expression of six genes in the mapped locus, further functional analysis is needed to narrow the list of gene candidates for the non-dormant evg phenotype. Here I report three sets of experiments designed to functionally test DAM genes in peach and their homologs in a model tree, hybrid poplar.
First I constructed overexpression and knockdown vectors …

Efficient And Stable Expression Of Gfp Through Wheat Streak Mosaic Virus-Based Vectors In Cereal Hosts Using A Range Of Cleavage Sites: Formation Of Dense Fluorescent Aggregates For Sensitive Virus Tracking, Satyanarayana Tatineni, Anthony J. Mcmechan, Gary L. Hein, Roy French

Department of Plant Pathology: Faculty Publications

A series of Wheat streak mosaic virus (WSMV)-based expression vectors were developed by engineering a cycle 3 GFP (GFP) cistron between P1 and HC-Pro cistrons with several catalytic/cleavage peptides at the Cterminus of GFP. WSMV-GFP vectors with the Foot-and-mouth disease virus 1D/2A or 2A catalytic peptides cleaved GFP from HC-Pro but expressed GFP inefficiently. WSMV-GFP vectors with homologous NIa-Pro heptapeptide cleavage sites did not release GFP from HC-Pro, but efficiently expressed GFP as dense fluorescent aggregates. However, insertion of one or two spacer amino acids on either side of NIb/CP heptapeptide cleavage site or deletion in HC-Pro cistron improved processing …

Another Really, Really Big Virus, James L. Van Etten

Department of Plant Pathology: Faculty Publications

Viruses with genomes larger than 300 kb and up to 1.2 Mb, which encode hundreds of proteins, are being discovered and characterized with increasing frequency. Most, but not all, of these large viruses (often referred to as giruses) infect protists that live in aqueous environments. Bioinformatic analyses of metagenomes of aqueous samples indicate that large DNA viruses are quite common in nature and await discovery. One issue that is perhaps not appreciated by the virology community is that large viruses, even those classified in the same family, can differ significantly in morphology, lifestyle, and gene complement. This brief commentary, which …

Motus, Morphology, And Biodiversity Estimation: A Case Study Using Nematodes Of The Suborder Criconematina And A Conserved 18s Dna Barcode, Thomas O. Powers, Timothy Harris, Rebecca Higgins, Peter Mullin, Lisa Sutton, Kirsten Powers

Department of Plant Pathology: Faculty Publications

DNA barcodes are increasingly used to provide an estimate of biodiversity for small, cryptic organisms like nematodes. Nucleotide sequences generated by the barcoding process are often grouped, based on similarity, into molecular operational taxonomic units (MOTUs). In order to get a better understanding of the taxonomic resolution of a 3’ 592-bp 18S rDNA barcode, we have analyzed 100 MOTUs generated from 214 specimens in the nematode suborder Criconematina. Previous research has demonstrated that the primer set for this barcode reliably amplifies all nematodes in the Phylum Nematoda. Included among the Criconematina specimens were 25 morphologically described species representing 12 genera. …

Presence Of Fusarium Spp. In Air And Soil Associated With Sorghum Fields, Deanna L. Funnell-Harris, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

Sorghum grain, valuable for feed, food, and bioenergy, can be colonized by several Fusarium spp.; therefore, it was of interest to identify possible sources of conidia. Analysis of air and soil samples provided evidence for the presence of propagules from Fusarium genotypes that may cause grain infections. Soil population estimates of members of the Gibberella fujikuroi species complex, that includes sorghum pathogens and other Fusarium spp., suggested that adequate inoculum for systemic infections was present. Conidia in air samples within two sorghum fields were collected by passive trapping for 2 years. Subsampled Fusarium isolates indicated that numbers of G. fujikuroi …

First Report Of Goss's Bacterial Wilt And Leaf Blight (Clavibacter Michiganensis Subsp. Nebraskensis) Of Corn In Texas, K. A. Korus, A. D. Timmerman, R. D. French-Monar, T. A. Jackson

Department of Plant Pathology: Faculty Publications

In September 2009, the University of Nebraska–Lincoln Plant and Pest Diagnostic Clinic received leaf samples of hybrid corn (Zea mays L.) displaying long, necrotic lesions with wavy margins. The lesions had discontinuous water-soaked spots that are indicative of Goss's bacterial wilt and leaf blight. The symptomatic leaves were submitted from Dallam County, located in the Texas Panhandle (northwest Texas). According to the USDA Farm Service Agency and the National Agricultural Statistics Service, in 2009 Dallam County had 54,025 ha planted to corn. This is approximately 19% of the total corn planted in the 26 counties in the Texas Panhandle …

Effects Of Integrating Cultivar Resistance And Fungicide Application On Fusarium Head Blight And Deoxynivalenol In Winter Wheat, Stephen N. Wegulo, William W. Bockus, John Hernandez Nopsa, Erick D. De Wolf, Kent M. Eskridge, Kamaranga H. S. Peiris, Floyd E. Dowell

Department of Plant Pathology: Faculty Publications

Fusarium head blight (FHB) or scab, incited by Fusarium graminearum, can cause significant economic losses in small grain production. Five field experiments were conducted from 2007 to 2009 to determine the effects on FHB and the associated mycotoxin deoxynivalenol (DON) of integrating winter wheat cultivar resistance and fungicide application. Other variables measured were yield and the percentage of Fusarium-damaged kernels (FDK). The fungicides prothioconazole + tebuconazole (formulated as Prosaro 421 SC) were applied at the rate of 0.475 liters/ha, or not applied, to three cultivars (experiments 1 to 3) or six cultivars (experiments 4 and 5) differing in their …

Characterization Of Three-Dimensional Spatial Aggregation And Association Patterns Of Brown Rot Symptoms Within Intensively Mapped Sour Cherry Trees, Sydney E. Everhart, Ashley Askew, Lynne Seymour, Imre J. Holb, Harald Scherm

Department of Plant Pathology: Faculty Publications

Characterization of spatial patterns of plant disease can provide insights into important epidemiological processes such as sources of inoculum, mechanisms of dissemination, and reproductive strategies of the pathogen population. While two-dimensional patterns of disease (among plants within fields) have been studied extensively, there is limited information on three-dimensional patterns within individual plant canopies. Reported here are the detailed mapping of different symptom types of brown rot (caused by Monilinia laxa) in individual sour cherry tree (Prunus cerasus) canopies, and the application of spatial statistics to the resulting data points to de-termine patterns of symptom aggregation and association. …

Synthesis, Linda H. Pardo, Linda H. Geiser, Mark E. Fenn, Charles T. Driscoll, Christine L. Goodale, Edith B. Allen, Jill S. Baron, Roland Bobbink, William D. Bowman, Christopher M. Clark, Bridget Emmett, Frank S. Gilliam, Tara Greaver, Sharon J. Hall, Erik A. Lilleskov, Lingli Liu, Jason A. Lynch, Knute Nadelhoffer, Steven S. Perakis, Molly J. Robin-Abbott, John L. Stoddard, Kathleen C. Weathers

Biological Sciences Faculty Research

Human activity in the last century has led to a substantial increase in nitrogen (N) emissions and deposition. This N deposition has reached a level that has caused or is likely to cause alterations to the structure and function of many ecosystems across the United States. One approach for quantifying the level of pollution that would be harmful to ecosystems is the critical loads approach. The critical load is dei ned as the level of a pollutant below which no detrimental ecological effect occurs over the long term according to present knowledge.

The objective of this project was to synthesize …

Floristic And Environmental Characteristics Of Sub-Boreal Peatlands Of Minnesota And Western Wisconsin, Kevin Douglas Clement

All Graduate Theses, Dissertations, and Other Capstone Projects

Peatland communities in the sub-boreal region of Minnesota and western Wisconsin were characterized by floristic composition, structure and environmental characteristics to determine the natural variation among peatland communities in the region and their shared associations with the boreal and temperate peatlands of North America. Floristic classification revealed five, distinct peatland community types, identified as Sphagnum Bogs, Herbaceous Fens, Forested Fens, Rich/Calcareous Fens and Phalaris anrundinacea dominated peatlands. Differences among sub-boreal peatlands largely reflected changes in the significant indicator and dominant plant species identified, which were found to exhibit high fidelities to a particular peatland community type. Floristic variations among sub-boreal …

Distributions And Abundances Of Microstegium Vimineum Along Forest Roadsides At The Grassy Hill Natural Area, Franklin County, Virginia, Gregory D. Turner

Virginia Journal of Science

In summer 2005, plots were surveyed along roads passing through forest habitats at the Grassy Hill Natural Area Preserve in Franklin County, Virginia to assess the distributions and abundances of Microstegium vimineum in transects located at increasing distances away from roadsides into forest interiors. Across plots, Microstegium was encountered almost exclusively in roadside transects, where abundances were relatively high. While forest composition and topographic features were similar across plots, percent canopy cover and leaf litter depth were greater in interior compared to roadside transects due to undisturbed tree canopies and ground cover located in interior plot areas. Results imply that …

Role Of The Sexual Cycle In Development Of Genotypic And Phenotypic Diversity In Gibberella Zeae, Sladana Bec

Theses and Dissertations--Plant Pathology

Gibberella zeae (anamorph Fusarium graminearum) is a homothallic ascomycete pathogen that is responsible for causing Fusarium head blight (FHB) of wheat and small grains. In addition to causing a reduction in yield, harvested grain is frequently contaminated with trichothecene mycotoxins that are harmful for human and animal health. Use of wheat varieties with resistance to FHB is an important strategy to lower its impact. In order to produce varieties with durable resistance, we must understand the origin and degree of genetic diversity present in the pathogen population. In my research, I focused my efforts on an investigation of the …

Saplings 2011, Sean M. Goins, Joseph Braner, Amy L. Myers, Charlie Jackson, Julia I. Chapman, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Sapling data (woody species >50 centimeters in height and <2.5 cm diameter at breast height) collected in 2011 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.

Overstory 2011, Sean M. Goins, Joseph Braner, Amy L. Myers, Charlie Jackson, Albert J. Burky, Julia I. Chapman, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Overstory data (woody species ≥2.5 centimeters in diameter at breast height) collected in 2011 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.

The Role Of The Acidic Domain Of The Toc159 Protein Import Receptor Family In Toc Complex Assembly In Arabidopsis Thaliana, Yi Chen

Theses and Dissertations (Comprehensive)

Most chloroplast proteins are encoded in the nucleus and translated in the cytosol with an N-terminal cleavable transit peptide, which can be recognized by the translocon at the outer envelope membrane of chloroplasts (Toc complex). The core Toc complex is composed of two GTPases, Toc159 and Toc34, and the Toc75 channel. atToc159, atToc132 and atToc120 are homologues of the Toc159 family in Arabidopsis, and have been shown to assemble into structurally and functionally distinct Toc complexes. Targeting of atToc159 to the chloroplast outer membrane is mediated by its GTPase (G-) domain. However, the role of the acidic (A-) domain in …

Role Of Lipids In Tombusvirus Replication, Monika Sharma

University of Kentucky Doctoral Dissertations

Positive-strand RNA virus group are the most abundant among viruses affecting plants and animals. To successfully achieve replication, these viruses usurp or co-opt host proteins. To facilitate the discovery of host factors involved in Tomato bushy stunt virus (TBSV), yeast has been developed as a surrogate model host. Genome-wide approaches covering 95% of yeast genes, has revealed approximately hundred factors that could affect virus replication. Among the identified host factors, there are fourteen yeast genes, which affect/regulate lipid metabolism of the host.

One of the identified host gene is ERG25, which is an important factor for sterol biosynthesis pathway, affecting …

Characterization Of G10h Promoter And Isolation Of Wrky Transcription Factors Involved In Catharanthus Terpenoid Indole Alkaloid Biosynthesis Pathway, Nitima Suttpanta

University of Kentucky Doctoral Dissertations

Catharanthus roseus produces a large array of terpenoid indole alkaloids (TIAs) that are an important source of natural or semi-synthetic anticancer drugs. Biosynthesis of TIAs is tissue-specific and induced by certain phytohormones and fungal elicitors, indicating the involvement of a complex transcriptional control network. However, the transcriptional regulation of the TIA pathway is poorly understood. This study reports the isolation and characterization of the G10H promoter and two WRKY transcription factors regulating TIA biosynthesis.

Geraniol 10-hydroxylase (G10H) controls the first committed step in the biosynthesis of terpenoid indole alkaloids (TIA). The C. roseus G10H promoter sequence was isolated by a …

Estimation Of Surface Soil Organic Matter Using A Ground-Based Active Sensor And Aerial Imagery, D. F. Roberts, V. I. Adamchuk, J. F. Shanahan, R. B. Ferguson, J. S. Schepers

Department of Agronomy and Horticulture: Faculty Publications

Active canopy sensors are currently being studied as a tool to assess crop N status and direct in-season N applications. The objective of this study was to use a variety of strategies to evaluate the capability of an active sensor and a wide-band aerial image to estimate surface soil organic matter (OM). Grid soil samples, active sensor reflectance and bare soil aerial images were obtained from six fields in central Nebraska before the 2007 and 2008 growing seasons. Six different strategies to predict OM were developed and tested by dividing samples randomly into calibration and validation datasets. Strategies included uniform, …

Soil Fertility And Crop Yields In Long-Term Organic And Conventional Cropping Systems In Eastern Nebraska, Samuel E. Wortman, Tomie D. Galusha, Stephen C. Mason, Charles A. Francis

Department of Agronomy and Horticulture: Faculty Publications

Organic agriculture aims to build soil quality and provide long-term benefits to people and the environment; however, organic practices may reduce crop yields. This long-term study near Mead, NE was conducted to determine differences in soil fertility and crop yields among conventional and organic cropping systems between 1996 and 2007. The conventional system (CR) consisted of corn (Zea mays L.) or sorghum (Sorghum bicolor (L.) Moench)–soybean (Glycine max (L.) Merr.)–sorghum or corn–soybean, whereas the diversified conventional system (DIR) consisted of corn or sorghum– sorghum or corn–soybean–winter wheat (wheat, Triticum aestivum L.). The animal manure-based organic system (OAM) …

Stacking Resistance Alleles From Wild And Domestic Soybean Sources Improves Soybean Cyst Nematode Resistance, Myungsik Kim, D. L. Hyten, Terry L. Niblack, Brian W. Diers

Department of Agronomy and Horticulture: Faculty Publications

The soybean cyst nematode (SCN; Heterodera glycines Ichinohe) is the most economically important soybean [Glycine max (L.) Merr.] pathogen in the United States. Field SCN populations are adapting to the narrowly based SCN resistance currently deployed in soybean cultivars. The objective of our research was to measure the effects of combinations of SCN resistance genes or quantitative trait loci (QTL) from the wild soybean (Glycine soja Siebold & Zucc.) PI 468916 and the domesticated soybean accessions PI 88788 and PI 437654. Two populations were developed to test the combinations of QTL and genes. Both populations segregated for the …

Moving Micronutrients From The Soil To The Seeds: Genes And Physiological Processes From A Biofortification Perspective, Brian M. Waters, Renuka P. Sankaran

Department of Agronomy and Horticulture: Faculty Publications

The micronutrients iron (Fe), zinc (Zn), and copper (Cu) are essential for plants and the humans and animals that consume plants. Increasing the micronutrient density of staple crops, or biofortification, will greatly improve human nutrition on a global scale. This review discusses the processes and genes needed to translocate micronutrients through the plant to the developing seeds, and potential strategies for developing biofortified crops.

2011 Wildflower Of The Year: White Oak, Quercus Alba, W. John Hayden

Biology Faculty Publications

Emblematic of strength and longevity, white oaks grace the deciduous forests of eastern North America.

Restoration Of Tall Fescue Pastures To Native Warm Season Grasslands: Does A Fungal Endophyte Symbiosis Play A Role In Restoration Success?, Sarah Lynn Hall

University of Kentucky Doctoral Dissertations

Tall fescue, a cool-season grass native to Europe, central Asia, and northern Africa, has been widely distributed throughout the U.S. for use as turf and forage. Following its widespread planting, its ability to associate with a toxic fungal endophyte, Neotyphodium coenophialum, was discovered. Research has linked this fescue-endophyte association with increased biotic and abiotic stress resistance in endophyte-infected (E+) versus endophyte-free (E-) plants, and these differences may affect the ability of land managers to eradicate tall fescue and restore native grasslands. I conducted three studies to examine whether E+ tall fescue plants respond differently to management than E- plants, …

T-Phylloplanin And Cis-Abienol, Two Natural Products From Tobacco Have Broad Spectrum, Anti-Fungal Activities, Brian Christopher King

University of Kentucky Doctoral Dissertations

Tobacco phylloplanins (T-phylloplanin) are a group of closely-related glycoproteins that are formed and disposed at the interface between the plant aerial surface (the phylloplane) and the atmosphere. They are synthesized in short procumbent trichomes and are secreted to aerial surfaces where they are thought to serve the plant as a first line of defense against fungal pathogens. Here it is shown using in vitro and in planta assays that tobacco and sunflower phylloplanins have broad-spectrum antifungal activities against spores - and also hyphae for two species - of several true fungi. Field tests show that T-phylloplanin reduces diseases caused by …