Digital Commons Network^™

Developing The Framework For A Risk Map For Mite Vectored Viruses In Wheat Resulting From Pre-Harvest Hail Damage, Anthony L. Nguy-Robertson, Arthur Zygielbaum, Anthony J. Mcmechan, Gary L. Hein, Stephen N. Wegulo, Abby R. Stilwell, Travis M. Smith

Department of Plant Pathology: Faculty Publications

There is a strong economic incentive to reduce mite-vectored virus outbreaks. Most outbreaks in the central High Plains of the United States occur in the presence of volunteer wheat that emerges before harvest as a result of hail storms. This study provides a conceptual framework for developing a risk map for wheat diseases caused by mite-vectored viruses based on pre-harvest hail events. Traditional methods that use NDVI were found to be unsuitable due to low chlorophyll content in wheat at harvest. Site-level hyperspectral reflectance from mechanically hailed wheat showed increased canopy albedo. Therefore, any increase in NIR combined with large …

Sequence Variation In Two Genes Determines The Efficacy Of Transmission Of Citrus Tristeza Virus By The Brown Citrus Aphid, S. J. Harper, N. Killiny, Satyanarayana Tatineni, S. Gowda, S. J. Cowell, T. Shilts, W. O. Dawson

Department of Plant Pathology: Faculty Publications

Vector transmission is an important part of the viral infection cycle, yet for many viruses little is known about this process, or how viral sequence variation affects transmission efficacy. Here we examined the effect of substituting genes from the highly transmissible FS577 isolate of citrus tristeza virus (CTV) in to the poorly transmissible T36-based infectious clone. We found that introducing p65 or p61 sequences from FS577 significantly increased transmission efficacy. Interestingly, replacement of both genes produced a greater increase than either gene alone, suggesting that CTV transmission requires the concerted action of co-evolved p65 and p61 proteins.

Diseases Of Trees In The Great Plains, Aaron D. Bergdahl, Alison Hill, Gerard C. Adams, Rachel A. Allison, John A. Appel, John Ball, James T. Blodgett, Kelly S. Burns, Whitney Cranshaw, Kelsey L. Dunnell, Mark L. Gleason, Mark O. Harrell, Thomas C. Harrington, Marcus B. Jackson, William R. Jacobi, Jennifer Juzwik, Megan M. Kennwlly, Les Koch, Jared M. Leboldus, Phillip A. Mason, Douglas L. Mcnew, Judith O'Mara, Hayley M. Nelson, Nicole Opbroek, Michael E. Ostry, Scott C. Redlin, Glen R. Stanosz, Laurie J. Stepanek, Ned Tisserat, Timothy C. Todd, James A. Walla, James J. Worrall, Simeon Wright

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Hosts, distribution, symptoms and signs, disease cycle, and management strategies are described for 84 hardwood and 32 conifer diseases in 56 chapters. Color illustrations are provided to aid in accurate diagnosis. A glossary of technical terms and indexes to hosts and pathogens also are included.

Scope

The purpose of this handbook is to assist users in diagnosing tree diseases and reducing their impact. Included are the most damaging diseases, along with some that are the subject of frequent inquiry although of minor importance. The diseases included were those encountered primarily on trees in conservation plantings such as windbreaks, farmstead plantings, …

Letter From The Dean, Lona Robertson

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

From Seed To Sky: Impacts Of Explosive Compounds On Vegetation Across Spatial And Developmental Scales, Stephen M. Via

Theses and Dissertations

Explosive compounds are broadly distributed across the globe as a result of nearly two centuries of munitions use in warfare and military activities. Two explosive compounds have seen disproportionate use; RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) and TNT (2-methyl- 1,3,5-trinitrobenzene), being the most commonly found explosives in the environment. The effects of explosives on biota have been studied in great detail; however, there is a general lack of understanding with regard to broader ecological impacts of these contaminants. My dissertation objective was to follow the impacts of explosive compounds on vegetation across scales. Impacts on vegetation at the species scale alter community composition via …

Plant Functional Trait And Hyperspectral Reflectance Responses To Comp B Exposure: Efficacy Of Plants As Landmine Detectors, Paul V. Manley Ii

Theses and Dissertations

At least 110 million landmines have been planted since the 1970s in about 70 nations, many of which remain in place today. Some risk of detection may be mitigated using currently available remote sensing techniques when vegetation is present. My study focused on using plants as phytosensors to detect buried explosives. I exposed three species representing different functional types (Cyperus esculentus (sedge), Ulmus alata (tree), Vitis labrusca (vine)) to 500 mg kg^-1 of Composition B (Comp B; 60/40 mixture of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) and 2,4,6-trinitrotoluene (TNT)), a commonly used explosive mixture, and measured functional traits and reflectance over …

Polyphenol Content And Differential Expression Of Flavonoid Biosynthetic Pathway Genes Of Fragaria Spp. With White Fruit, Sutapa Roy

Theses and Dissertations--Plant and Soil Sciences

Strawberries are a rich source of polyphenols which contribute to berry color and plant disease resistance, and have been shown to lower the risk of many chronic when consumed. While a considerable body of work exists on the polyphenolic composition of commercial strawberry (Fragaria x ananassa Duch.), less information is available concerning polyphenols in Fragaria vesca, or Alpine strawberry, considered a model system for the Rosaceae family of crop species. The study of natural and genetically-engineered F. vesca mutants with white fruit can provide unique insight into regulation of metabolic flux through the complex branched phenylpropanoid/flavonoid biosynthetic pathway. …

Transcriptional Regulation Of Specialized Metabolites In Arabidopsis Thaliana And Catharanthus Roseus, Craig M. Schluttenhofer

Theses and Dissertations--Plant and Soil Sciences

For millennia humans have utilized plant specialized metabolites for health benefits, fragrances, poisons, spices, and medicine. Valued metabolites are often produced in small quantities and may command high prices. Understanding when and how the plant synthesizes these compounds is important for improving their production. Phytohormone signaling cascades, such as jasmonate (JA) activate or repress transcription factors (TF) controlling expression of metabolite biosynthetic genes. TFs regulating specialized metabolite biosynthetic genes can be manipulated to engineer plants with increased metabolite production.

WRKY transcription factor are known components of both JA signaling cascades and regulation of specialized metabolism. The presence of WRKY binding …

The Effects Of Manufactured Nanomaterial Transformations On Bioavailability, Toxicity And Transcriptomic Responses Of Caenorhabditis Elegans, Daniel L. Starnes

Theses and Dissertations--Plant and Soil Sciences

In recent decades, there has been a rapid expansion in the use of manufactured nanoparticles (MNPs). Experimental evidence and material flow models predict that MNPs enter wastewater treatment plants and partition to sewage sludge and majority of that sludge is land applied as biosolids. During wastewater treatment and after land application, MNPs undergo biogeochemical transformations (aging). The primary transformation process for silver MNPs (Ag-MNPs) is sulfidation, while zinc oxide MNPs (ZnO-MNPs) most likely undergo phosphatation and sulfidation. Our overall goal was to assess bioavailability and toxicogenomic impacts of both pristine, defined as-synthesized, and aged Ag- and ZnO-MNPs, as well as …

Evaluating The Evolutionary And Genetic Relationships Of The Andean Orchids Of Northwestern Ecuador, Kylie Bucalo

Theses and Dissertations

DNA barcoding is a molecular based technique used to separate and identify individual species. Here we establish a DNA Barcode library for the orchid flora of an Andean cloud forest in Northwestern Ecuador. The library contains 135 matK and 136 rbcL DNA Barcodes representing over 33 Orchidaceae genera. Sequence analysis shows percent species resolution was higher for matK (98.8%) than rbcL (70.24%), with a large portion of the unresolved species for the rbcL loci coming from taxonomically complex genera in the subtribe Pleurothallidinae. Neighbor Joining (NJ) trees revealed that the orchid flora of Siempre Verde is divided taxonomically into …

Seeing Red In A Sea Of Green: Anthocyanin Production In A Carnivorous Plant, Pinguicula Planifolia, Jenna Annis

Masters Theses

The Southeastern United States is a biological hot-spot for carnivorous plants, with over half of the North American species occurring along the Gulf Coast. Pinguicula planifolia Chapman is one of six carnivorous perennial butterwort species found in the Florida Panhandle. Among these species, only P. planifolia expresses a distinct variation of red coloration on its leaves. The functional role of foliar anthocyanins may include stress response to drought and nutrient deficiency, herbivory defense, free radical scavenging, and photoprotection. Carnivorous plant leaves face strong selection pressures to optimize prey capture and nutrient absorption. Given the frequency of these red pigments in …

Small Unmanned Aerial Vehicles (Micro-Uavs, Drones) In Plant Ecology, Mitchell B. Cruzan, Ben G. Weinstein, Monica R. Grasty, Brendan F. Kohrn, Elizabeth C. Hendrickson, Tina M. Arredondo, Pamela G. Thompson

Biology Faculty Publications and Presentations

Premise of the study: Low-elevation surveys with small aerial drones (micro–unmanned aerial vehicles [UAVs]) may be used for a wide variety of applications in plant ecology, including mapping vegetation over small- to medium-sized regions. We provide an overview of methods and procedures for conducting surveys and illustrate some of these applications.

Methods: Aerial images were obtained by flying a small drone along transects over the area of interest. Images were used to create a composite image (orthomosaic) and a digital surface model (DSM). Vegetation classification was conducted manually and using an automated routine. Coverage of an individual species …

Plpt 496/892: Disease Dynamics & Evolution—A Peer Review Of Teaching Project Benchmark Portfolio, Sydney E. Everhart

UNL Faculty Course Portfolios

This benchmark course portfolio was developed as a component of the University of Nebraska Peer Review of Teaching. The course selected for this portfolio was a new course developed and taught as an Independent Study PLPT 496/892. The working title for the course was Disease Dynamics and Evolution. This course was designed to cover core concepts of disease ecology and pathogen emergence/evolution. Concepts were organism-agnostic and important for understanding infectious diseases of humans, animals, and plants. The course format was lecture-based and inquiry driven, using primary literature as case studies. The goal of this course was to use interesting and …

Growing South Dakota (Winter 2016), College Of Agriculture &. Biological Sciences

Growing South Dakota (Publication of the College of Agriculture, Food and Environmental Sciences)

This issue includes the 2015 South Dakota Agricultural Experiment Station Annual Report.

[Page] 2 Director's Message
[Page] 3 Concentrating On Cattle: Researcher Studying Mechanics To Improve Reproduction Efficiency In Beef Cattle
[Page] 5 At The Forefront: SDSU Diagnostic Lab Scientists Sequence Avian Influenza Genome
[Page] 6 Seeking Superior Wheat: Breeder Using Extensive Genome Testing To Improve Winter Wheat Cultivars
[Page] 8 Profiles In Leadership: Plant And Fungi Interactions May Offer New Plant Production Possibilities
[Page] 9 Targeting Emerging Diseases: Plant Pathologists Working To Better Manage Soybean & Sunflower Diseases
[Page] 10 Compelling New Crop: Carinata Offers Potential For Crop Diversity, …

Development Of Functional Markers For Resistance To Leaf Scald In Sugarcane, Andres Felipe Gutierrez Viveros

LSU Doctoral Dissertations

Leaf scald, caused by Xanthomonas albilineans, is a major sugarcane disease worldwide. The disease is managed primarily with resistant cultivars obtained through classical breeding; however, the erratic symptom expression hinders the reliability and reproducibility of the selection process. The development of molecular markers associated with incompatible/compatible reaction can overcome this limitation. Suppression subtractive hybridization (SSH) and quantitative trait locus (QTL) mapping were the strategies used to find leaf scald resistance-associated genes and molecular markers in sugarcane. SSH results showed that genes involved in signal perception and transduction, and DNA binding, were highly expressed in the resistant clone LCP 85-384 compared …

Spatial Separation Of Semiochemical Lurem-Tr And Entomopathogenic Fungi To Enhance Their Compatibility And Infectivity In An Autoinoculation System For Thrips Management, David K. Mfuti, Sevgan Subramanian, Rob Whm Van Tol, Gerrie L. Wiegers, Willem J. De Kogel, Saliou Niassy, Hannalene Du Plessis, Sunday Ekesi, Nguya K. Maniania

All Peer-Reviewed Publications

BACKGROUND: The effect of spatial separation of the semiochemical Lurem-TR, which has been found to inhibit conidia of entomopathogenic fungi when put together, on the persistence of conidia of Metarhizium brunneum and M. anisopliae was evaluated in the greenhouse and field in order to develop an autodissemination strategy for the management of Megalurothrips sjostedti on cowpea crop. Influence of spatial separation of the semiochemical on thrips attraction and conidial acquisition by thrips from the autoinoculation device was also investigated in the field. RESULTS: Persistence of conidia of M. brunneum and M. anisopliae increased with distance of separation of Lurem-TR. Direct …

02. My Career In Prairie Research And Restoration, Peter Schramm

North American Prairie Conference Proceedings

No abstract provided.

Using Linear Mixed Models To Analyze Native And Non-Native Species Abundances In Coastal Sage Scrub, Kaylee Anderson

Scripps Senior Theses

Coastal Sage Scrub (CSS) is a low scrubland plant community native to the coasts of California, housing many threatened and endangered species. Due to the invasion of non-native plants, many areas of CSS have type converted to annual grasslands and the fire frequency has accelerated; fire in turn, may facilitate further invasion, leading to a loss of biodiversity. While many studies document post-fire succession in these communities, pre-fire data are rarely available for comparison, especially data on seedling emergence. I analyzed post-fire recovery of a type-converted grassland community, comparing seedling emergence data for the first and third year after fire …

Impact Of Reduced Tillage And Crop Residue Management On Soil Properties And Crop Yields In A Long-Term Trial In Western Kenya, Jeremiah M. Okeyo, Jay Norton, Saidou Koala, Boaz Waswa, Job Kihara, Andre Bationo

All Peer-Reviewed Publications

Sustainable farming practices are required to address the persistent problems of land degradation and declining crop productivity in Sub-Saharan Africa. Approaches such as reducing tillage and retaining crop residues as mulch are potential entry points for smallholder farmers to move towards sustainability. In this study, we assessed the impact of reduced tillage (RT) compared with conventional tillage (CT), each combined with crop residue reapplication, on soil quality indicators and crop yields under an 8-year trial in western Kenya. Our results indicate that RT combined with crop residue reapplication enhanced soil physical quality through increased macroaggregate (>2000μm) proportions and mean …

What Would The Babel Fish Say?, Monica Gagliano

Animal Sentience

Starting with its title, Key’s (2016) target article advocates the view that fish do not feel pain. The author describes the neuroanatomical, physiological and behavioural conditions involved in the experience of pain in humans and rodents and confidently applies analogical arguments as though they were established facts in support of the negative conclusion about the inability of fish to feel pain. The logical reasoning, unfortunately, becomes somewhat incoherent, with the arbitrary application of the designated human criteria for an analogical argument to one animal species (e.g., rodents) but not another (fish). Research findings are reported selectively, and questionable interpretations are …

Cryptic Species: A Leitmotif Of Contemporary Mycology Has Challenges And Benefits For Plant Pathologists, Frank M. Dugan, Sydney Everhart

Department of Plant Pathology: Faculty Publications

Multiple traditional species names for plant pathogenic fungi have been supplemented with new names that delimit formerly cryptic species. In separate instances, isolates within a species are clearly differentiated by both phylogeny and distinctive pathogenic traits and are assigned sub-specific designations. These new species names and the sub-specific designations are both cases of cryptic species that are, in some instances, relevant and/or critical for plant disease management. Here we provide examples of such instances in which newly described taxa differ from the original (“parent”) in phenotypic traits of importance to plant disease management: host range, fungicide sensitivity, environmental niche, metabolite …

Chloroviruses N-Linked Glycans Share A New Type Of Conserved Core Architecture Unprecedented In Any Form Of Life / [Published As] N-Linked Glycans Of Chloroviruses Sharing A Core Architecture Without Precedent, Cristina De Castro, Immacolata Speciale, Garry Duncan, David Dunigan, Irina Agarkova, Rosa Lanzetta, Luisa Sturiale, Angelo Palmigiano, Domenico Garozzo, Antonio Molinaro, Michela Tonetti, James L. Van Etten

James Van Etten Publications

N-glycosylation is a fundamental modification of proteins that exists in the three domains of life and in some viruses, including the chloroviruses, for which a new type of core N-glycan is described. This N-glycan core structure common to all chloroviruses is a pentasaccharide with a β-glucose linked to an asparagine residue that is not located in the typical sequon N-X-T/S. The glucose is linked to a terminal xylose unit and a hyperbranched fucose, in turn substituted with a terminal galactose and a second xylose residue. The third position of the fucose unit is always linked to a rhamnose, which is …

Fidelity And Survival Of Breeding Mallards In The Nebraska Sandhills, Zachary J. Cunningham, Larkin Powell, Mark P. Vrtiska

The Prairie Naturalist

Assessment of demographic parameters of a population allows managers to better understand factors affecting populations and increase efficiency of conservation efforts. Few data on demographics exist for mallards (Anas platyrhynchos) breeding in the Nebraska Sandhills. Thus, we used banding data to estimate probabilities of fidelity, survival, band recovery, and recapture of mallards banded in the eastern Sandhills, 2005–2008. Our recapture probability estimate for mallards was 0.074 (95% CI: 0.033–0.158), and the recovery probability estimate was 0.300 (95% CI: 0.156–0.497). Mallard annual survival was 0.795 (95% CI: 0.609–0.906) with a fidelity probability of 0.618 (95% CI: 0.283–0.868). High annual …

A Forest Vulnerability Index Based On Drought And High Temperatures, David Mildrexler, Zhiqiang Yang, Warren B. Cohen, David M. Bell

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Increasing forest stress and tree mortality has been directly linked to combinations of drought and high temperatures. The climatic changes expected during the next decades – large increases in mean temperature, increased heat waves, and significant long-term regional drying in the western USA – will likely increase chronic forest stress and mortality. The aim of this research is to develop and apply a new forest vulnerability index (FVI) associated with drought and high temperatures across the Pacific Northwest region (PNW; Oregon and Washington) of the USA during the MODIS Aqua era (since 2003). Our technique incorporates the alterations to canopy …

Pronghorn Habitat Suitability In The Texas Panhandle, Nathan P. Duncan, Samantha S. Kahl, Shawn S. Gray, Christopher J. Salice, Richard D. Stevens

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

Habitat quality is an important factor that can greatly affect wildlife populations. Pronghorn (Antilocapra americana) habitat in the Texas Panhandle, USA has been lost through growth of human settlements and agricultural lands. We determined the most pertinent environmental variables affecting habitat selection using multiple methods, including a search of peer-reviewed literature, expert opinion ranking, and habitat suitability modeling. We determined quality and extent of pronghorn habitat in the Texas Panhandle using the MAXENT modeling environment to build a presence-only habitat suitability model based on global positioning system (GPS) locations collected via aerial surveys. Our habitat suitability model indicated …

Pyrodiversity Promotes Avian Diversity Over The Decade Following Forest Fire, Morgan W. Tingley, Viviana Ruiz-Gutierrez, Robert L. Wilkerson, Christine A. Howell, Rodney B. Siegel

United States Department of Agriculture, Forest Service / University of Nebraska-Lincoln: Faculty Publications

An emerging hypothesis in fire ecology is that pyrodiversity increases species diversity.We test whether pyrodiversity—defined as the standard deviation of fire severity—increases avian biodiversity at two spatial scales, and whether and how this relationship may change in the decade following fire. We use a dynamic Bayesian community model applied to a multi-year dataset of bird surveys at 1106 points sampled across 97 fires in montane California. Our results provide strong support for a positive relationship between pyrodiversity and bird diversity. This relationship interacts with time since fire, with pyrodiversity having a greater effect on biodiversity at 10 years post-fire than …

Genomic Prediction Of Single Crosses In The Early Stages Of A Maize Hybrid Breeding Pipeline, Dnyaneshwar C. Kadam, Sarah M. Potts, Martin O. Bohn, Alexander E. Lipka, Aaron J. Lorenz

Department of Agronomy and Horticulture: Faculty Publications

Prediction of single-cross performance has been a major goal of plant breeders since the beginning of hybrid breeding. Recently, genomic prediction has shown to be a promising approach, but only limited studies have examined the accuracy of predicting single-cross performance. Moreover, no studies have examined the potential of predicting single crosses among random inbreds derived from a series of biparental families, which resembles the structure of germplasm comprising the initial stages of a hybrid maize breeding pipeline. The main objectives of this study were to evaluate the potential of genomic prediction for identifying superior single crosses early in the hybrid …

Smokey Comes Of Age: Unmanned Aerial Systems For Fire Management, Dirac L. Twidwell Jr., Craig R. Allen, Carrick Detweiler, James Higgins, Christian Laney, Sebastian Elbaum

Department of Agronomy and Horticulture: Faculty Publications

During the past century, fire management has focused on techniques both to protect human communities from catastrophic wildfire and to maintain fire-dependent ecological systems. However, despite a large and increasing allocation of resources and personnel to achieve these goals, fire management objectives at regional to global scales are not being met. Current fire management techniques are clearly inadequate for the challenges faced by fire managers, and technological innovations are needed. Advances in unmanned aerial systems (UAS) technology provide opportunities for innovation in fire management and science. In many countries, fire management organizations are beginning to explore the potential of UAS …

Information Thermodynamics Of Cytosine Dna Methylation, Robersy Sanchez Rodriguez, Sally Ann Mackenzie

Department of Agronomy and Horticulture: Faculty Publications

Cytosine DNA methylation (CDM) is a stable epigenetic modification to the genome and a widespread regulatory process in living organisms that involves multicomponent molecular machines. Genome-wide cytosine methylation patterning participates in the epigenetic reprogramming of a cell, suggesting that the biological information contained within methylation positions may be amenable to decoding. Adaptation to a new cellular or organismal environment also implies the potential for genome-wide redistribution of CDM changes that will ensure the stability of DNA molecules. This raises the question of whether or not we would be able to sort out the regulatory methylation signals from the CDM background …

Horizontal Gene Acquisitions, Mobile Element Proliferation, And Genome Decay In The Host-Restricted Plant Pathogen Erwinia Tracheiphila, Lori R. Shapiro, Erin D. Scully, Timonthy J. Straub, Jihye Park, Andrew G. Stephenson, Gwyn A. Beattie, Mark L. Gleason, Roberto Kolter, Miguel C. Coelho, Consuelo M. De Moraes, Mark C. Mescher, Olga Zhaxybayeva

Department of Agronomy and Horticulture: Faculty Publications

Modern industrial agriculture depends on high-density cultivation of genetically similar crop plants, creating favorable conditions for the emergence of novel pathogens with increased fitness in managed compared with ecologically intact settings. Here, we present the genome sequence of six strains of the cucurbit bacterial wilt pathogen Erwinia tracheiphila (Enterobacteriaceae) isolated from infected squash plants in New York, Pennsylvania, Kentucky, and Michigan. These genomes exhibit a high proportion of recent horizontal gene acquisitions, invasion and remarkable amplification of mobile genetic elements, and pseudogenization of approximately 20% of the coding sequences. These genome attributes indicate that E. tracheiphila recently emerged as a …