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Detecting Genomic Regions Responsible For Resistance In Arabidopsis, Valeria Cancino, Anjali Iyer-Pascuzzi, Rucha Karve

The Summer Undergraduate Research Fellowship (SURF) Symposium

Ralstonia solanacearum is a soil-borne plant root colonizing pathogen and the casual agent of bacterial wilt (BW) disease. BW leads to severe yield loss in a wide variety of agricultural commodity crops, such as tomato, banana, and pepper. In this study, we look at the plant-pathogen interaction between Ralstonia solanacearum and various ecotypes of Arabidopsis thaliana with the goal of finding resistant ecotypes. To identify resistant ecotypes, seeds are first sterilized and left to soak in the dark. Then the seeds are plated on agar media, transferred to a growth chamber, and allowed to grow for 5 days. On day …

Chlorophyll Synthase Under Epigenetic Surveillance Is Critical For Vitamin E Synthesis, And Altered Expression Affects Tocopherol Levels In Arabidopsis, Chunyu Zhang, Wei Zhang, Guodong Ren, Denli Li, Rebecca E. Cahoon, Ming Chen, Yongming Zhou, Bin Yu, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty Publications

Chlorophyll synthase catalyzes the final step in chlorophyll biosynthesis: the esterification of chlorophyllide with either geranylgeranyl diphosphate or phytyl diphosphate (PDP). Recent studies have pointed to the involvement of chlorophyll-linked reduction of geranylgeranyl by geranylgeranyl reductase as a major pathway for the synthesis of the PDP precursor of tocopherols. This indirect pathway of PDP synthesis suggests a key role of chlorophyll synthase in tocopherol production to generate the geranylgeranyl-chlorophyll substrate for geranylgeranyl reductase. In this study, contributions of chlorophyll synthase to tocopherol formation in Arabidopsis (Arabidopsis thaliana) were explored by disrupting and altering expression of the corresponding gene …

Once Again, My Epiphyllum: Hope, Joy And Excitement, Wenling Ma

Librarian Publications

Wenling Ma describes the second flowering of her Epiphyllum in August 2015.

Transport Regimes And Spread Of The Common Reed, Phramites Australis, In The Saco River, Me, Usa, Michelle A. Slater

All Theses And Dissertations

Allee effects are important to species invasions because population growth may be limited by low outcrossing potential in newly founded populations leading to depressed levels of fitness. Non-native Phragmites australis (common reed) has been present in the United States for over 200 years, but has been slow to reach some areas, possibly owing to the Allee phenomenon, whereby young or isolated Phragmites patches with initially low genotypic richness are slow to recruit viable seedlings due to inbreeding, which limits the rate of patch expansion. In order to explore the importance of the Allee effect in a recently invaded system, the …

Removal Of Heavy Metal Ions From Aqueous Solution Using Rice Husks-Based Adsorbents, Fanuel J Ligate, James E.G Mdoe

Tanzania Journal of Science

This study reports on the preparation and characterization of rice husks-based adsorbents and their application in the removal of heavy metal ions from aqueous solution. Three different adsorbents were developed: rice husks ash (RHA), rice husks ash-derived silica (RHS) and triaminopropyl-silica hybrid (TSH-R). The prepared materials were characterized by acid titration, Attenuated Total Reflectance Fourier Transform Infrared (ATR-FTIR) spectroscopy, Scanning Electron Microscopy-Energy Dispersive X-ray (SEM-EDX) spectroscopy and nitrogen physisorption analysis. Results from the ATR-FTIR analysis indicated that pure silica was obtained from RHA and that after surface modification the triaminopropyl group was successfully attached onto the silica framework with a …

Agro-Waste As Source Of Fine And Industrial Chemicals: Synthesis Of 2-Formyl-6-Hydroxybenzoic Acid And 4-Methoxyisobenzofuran-1,3-Dione From Cashew Nut Shell Liquid, Lydia Kisula, Stephen J.M. Mdachi, Charles De Koning, Quintino A. Mgani

Tanzania Journal of Science

This paper reports on the synthesis of 2-formyl-6-hydroxybenzoic acid (8) and 4-methoxyisobenzofuran-1,3-dione (10) from a renewable natural material Cashew Nut Shell Liquid (CNSL) achieved in five and seven steps, respectively. Anacardic acid was isolated from CNSL, dimethoxylated into (E)-methyl 2-methoxy-6-(pentadec-8-enyl)benzoate which was subsequently hydrogenated into methyl 2-methoxy-6-pentadecylbenzoate. Benzylic bromination of the methoxyester, and dehydrobromination afforded (E)-methyl 2-methoxy-6-(pentadec-1-enyl)benzoate which upon ozonolysis gave methyl 2-formyl-6-methoxybenzoate. Oxidation and dehydration of 8 formed methoxyphthalic anhydride (10). The work reported in this paper has further demonstrated the resourcefulness of cashew nut shell liquid as a renewable natural resource for synthesis of fine and industrial chemicals.

Occurrence Of An Herbicide-Resistant Plant Trait In Agricultural Field Margins, Karla L. Gag, David J. Gibson, Bryan G. Young, Julie M. Young, Joseph L. Matthews, Stephen C. Weller, Robert G. Wilson

Department of Agronomy and Horticulture: Faculty Publications

Agricultural environments allow study of evolutionary change in plants. An example of evolution within agroecological systems is the selection for resistance to the herbicide glyphosate within the weed, Conyza canadensis. Changes in survivorship and reproduction associated with the development of glyphosate resistance (GR) may impact fitness and influence the frequency of occurrence of the GR trait. We hypothesized that site characteristics and history would affect the occurrence of GR C. canadensis in field margins. We surveyed GR occurrence in field margins and asked whether there were correlations between GR occurrence and location, crop rotation, GR crop trait rotation, crop type, …

Osmotic Stress Induces Phosphorylation Of Histone H3 At Threonine 3 In Pericentromeric Regions Of Arabidopsis Thaliana, Zhen Wang, Juan Armando Casas-Mollano, Jianping Xu, Jean-Jack M. Riethoven, Chi Zhang, Heriberto Cerutti

Center for Plant Science Innovation: Faculty Publications

Histone phosphorylation plays key roles in stress-induced transcriptional reprogramming in metazoans but its function(s) in land plants has remained relatively unexplored. Here we report that an Arabidopsis mutant defective in At3g03940 and At5g18190, encoding closely related Ser/Thr protein kinases, shows pleiotropic phenotypes including dwarfism and hypersensitivity to osmotic/salt stress. The double mutant has reduced global levels of phosphorylated histone H3 threonine 3 (H3T3ph), which are not enhanced, unlike the response in the wild type, by drought-like treatments. Genome-wide analyses revealed increased H3T3ph, slight enhancement in trimethylated histone H3 lysine 4 (H3K4me3), and a modest decrease in histone H3 occupancy …

Osmotic Stress Induces Phosphorylation Of Histone H3 At Threonine 3 In Pericentromeric Regions Of Arabidopsis Thaliana, Zhen Wang, Juan Casas-Mollano, Jianping Xu, Jean-Jack Riethoven, Chi Zhang, Heriberto D. Cerutti

Center for Plant Science Innovation: Faculty Publications

Histone phosphorylation plays key roles in stress-induced transcriptional reprogramming in metazoans but its function(s) in land plants has remained relatively unexplored. Here we report that an Arabidopsis mutant defective in At3g03940 and At5g18190, encoding closely related Ser/Thr protein kinases, shows pleiotropic phenotypes including dwarfism and hypersensitivity to osmotic/salt stress. The double mutant has reduced global levels of phosphorylated histone H3 threonine 3 (H3T3ph), which are not enhanced, unlike the response in the wild type, by drought-like treatments. Genome-wide analyses revealed increased H3T3ph, slight enhancement in trimethylated histone H3 lysine 4 (H3K4me3), and a modest decrease in histone H3 occupancy …

The Pioneer Of Santa Rosa Island, Andrea Martinez, Michael Perez, Kathryn Mceachern, Sarah Chaney, Ken Niessen

STAR Program Research Presentations

Santa Rosa Island which is part of the Channel Islands in California has a ranching history that goes as far back as the year 1843. While rich in history, the island is no longer “rich” in native plant populations due to the sheep, cattle and other livestock that once occupied the island. As a result of these grazers that the ranchers livelihood depended on, a great disturbance in the native plant population took place. It is up to plants such as Baccharis pilularis, commonly known as Coyote brush, to assist these endangered and threatened plants to once again flourish …

Pythium: Characterization Of Resistance In Soybean And Population Diversity, Keiddy Esperanza Urrea Romero

Graduate Theses and Dissertations

Pythium spp. are an important group of pathogens causing stand losses in Arkansas soybean production. New inoculation methods and advances in molecular techniques allow a better understanding of cultivar resistance and responses of Pythium communities to cultural practices. The objectives of this research were to i) characterize the resistance of soybean to P. aphanidermatum with two phenotyping assays that evaluated the seed rot phase of the disease; and ii) understand the effect of long term crop rotation on species diversity and iii) to determine the effect of location, temperature and continuous soybean and soybean-rice rotation on Pythium spp. diversity in …

Investigations Of Ethylene And Ethylene Inhibition, Ball Lie, And Synthetic Turf Color, William Daniel Strunk

Graduate Theses and Dissertations

This dissertation is comprised of several studies over three unrelated areas of focus. Chapters two and three investigate the role of the hormone ethylene on growth of creeping bentgrass through (1) exposure of turf to exogenous ethylene and (2) testing an ethylene inhibiting compound for use to alleviate stress related injury. Previous research demonstrated a correlation of stress injury and ethylene and lessening of injury through ethylene inhibition, but little work has been conducted evaluating the direct effects of ethylene. These studies failed to confirm findings in previous research. Chapters four and five aim to illustrate the impact of turfgrass …

When It Comes To Clethra: Roots Matter, W. John Hayden

Biology Faculty Publications

Roots, too often, are out of sight and out of mind, but they are critical for vigorous, healthy plant growth. All plant enthusiasts—including gardeners, farmers, foresters, and naturalists—should think about and appreciate roots if they wish to acquire a holistic understanding of plant biology. This article introduces readers to the mycorrhizal roots of the 2015 VNPS Wildflower of the Year, Clethra alnifolia (Sweet Pepperbush), and explores the diversity of mycorrhizae in a closely related family, Ericaceae.

Biochemical And Proteomic Profiling Of Maize Endosperm Texture And Protein Quality, Kyla J. Morton

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

The research described herein, focuses on the biochemical and proteomic analysis of the maize endosperm and what influences kernel texture. Quality Protein Maize (QPM) is a hard endosperm version of the high-lysine opaque2 (o2) mutant but the genes involved in modifying the soft o2 endosperm are unknown. Pyrophosphate (PPi)-dependent fructose 6-phosphate 1-phosphotransferase (PFP) catalyzes the ATP-independent conversion of fructose 6-phosphate to fructose 1, 6-bisphosphate in glycolysis. We found a large increase in transcript and protein levels of the alpha regulatory subunit of PFP (PFPα) in QPM endosperm. In vitro enzyme assays show a significant increase in forward PFP …

Alliaria Petiolata (M.Bieb.) Cavara & Grande [Brassicaceae], An Invasive Herb In The Southern Ozark Plateaus: A Comparison Of Species Composition And Richness, Soil Properties, And Earthworm Composition And Biomass In Invaded Versus Non-Invaded Sites, Jennifer D. Ogle

Graduate Theses and Dissertations

Invasive species are widely recognized as organisms that severely alter ecosystem processes in the habitats to which they are introduced. Alliaria petiolata is one of the most important invasive plants in forests of the northern United States. This study examined the geographic distribution of the plant in the southern Ozarks, as well as the effect that it may be having on natural processes within forests of the region by comparing plant species richness, plant cover, and soil properties in invaded and non-invaded plots. It was found that A. petiolata is not significantly altering species richness, cover, or soil properties in …

The Impact Of Herbicide-Resistant Rice And Hybrid Rice Technology On Weedy Rice Evolution, Vijay Singh

Graduate Theses and Dissertations

Weedy rice (Oryza sativa L.) competes aggressively with rice, reducing yields and grain quality. ClearfieldTM rice, is nontransgenic herbicide-resistant (HR) rice introduced in 2002 to control weedy rice, has resulted in ALS-resistant weedy rice due to gene flow. Volunteers of ClearfieldTM rice (F2) accelerate the HR weedy rice evolution by acting as agents of gene flow. Weedy rice (89) collected from 11 counties in Arkansas were screened for resistance in a field experiment in Stuttgart (2011). Seventy-nine percent of accessions were resistant to imazethapyr and harbored S653N mutation. These HR weedy accessions were outcrosses of ClearfieldTM rice and weedy rice. …

Temperature In The Cotton (Gossypium Hirsutum L.) Canopy And Effects On Cotton Leaf And Boll Growth, Maria Soledad Berlangieri Costa

Graduate Theses and Dissertations

Cotton development and yield are negatively influenced by extremes temperatures, mainly during reproductive stage. Ambient air temperature is used to evaluate temperature stress effect on yield under field conditions; however, there is evidence that actual temperatures in the canopy where bolls develop are different. In terms of cotton responses, there is limited research about the effects of elevated day and night temperatures upon boll carbohydrate content, size, and boll respiration. Field and growth chamber experiments were performed during 2014-2015 using the cotton (Gossypium hirsutum L.) cultivar DP0912B2RF. Field studies for determining temperature gradients through the canopy consisted of two planting …

The Argos Gene Family Functions In A Negative Feedback Loop To Desensitize Plants To Ethylene, Muneeza I. Rai, Xiaomin Wang, Derek M. Thibault, Hyo Jung Kim, Matthew M. Bombyk, Brad M. Binder, Samina N. Shakeel, G. Eric Schaller

Dartmouth Scholarship

Ethylene plays critical roles in plant growth and development, including the regulation of cell expansion, senescence, and the response to biotic and abiotic stresses. Elements of the initial signal transduction pathway have been determined, but we are still defining regulatory mechanisms by which the sensitivity of plants to ethylene is modulated. We report here that members of the ARGOS gene family of Arabidopsis, previously implicated in the regulation of plant growth and biomass, function as negative feedback regulators of ethylene signaling. Expression of all four members of the ARGOS family is induced by ethylene, but this induction is blocked in …

Fuels And Fires Influence Vegetation Via Above- And Belowground Pathways In A High-Diversity Plant Community, Paul R. Gagnon, Heather A. Passmore, Matthew Slocum, Jonathan A. Myers, Kyle E. Harms, William J. Platt, C.E. Timothy Paine

Biology Faculty Research

1. Fire strongly influences plant populations and communities around the world, making it an important agent of plant evolution. Fire influences vegetation through multiple pathways, both above- and belowground. Few studies have yet attempted to tie these pathways together in a mechanistic way through soil heating even though the importance of soil heating for plants in fire-prone ecosystems is increasingly recognized.
2. Here we combine an experimental approach with structural equation modelling (SEM) to simultaneously examine multiple pathways through which fire might influence herbaceous vegetation. In a high-diversity longleaf pine groundcover community in Louisiana, USA, we manipulated fine-fuel biomass and monitored the …

Combinatorial Effects Of Fatty Acid Elongase Enzymes On Nervonic Acid Production In Camelina Sativa, Dongxin Huai, Yuanyuan Zhang, Chunyu Zhang, Edgar B. Cahoon, Yongming Zhou

Center for Plant Science Innovation: Faculty Publications

Very long chain fatty acids (VLCFAs) with chain lengths of 20 carbons and longer provide feedstocks for various applications; therefore, improvement of VLCFA contents in seeds has become an important goal for oilseed enhancement. VLCFA biosynthesis is controlled by a multi-enzyme protein complex referred to as fatty acid elongase, which is composed of β-ketoacyl-CoA synthase (KCS), β-ketoacyl-CoA reductase (KCR), β-hydroxyacyl-CoA dehydratase (HCD) and enoyl reductase (ECR). KCS has been identified as the ratelimiting enzyme, but little is known about the involvement of other three enzymes in VLCFA production. Here, the combinatorial effects of fatty acid elongase enzymes on VLCFA production …

Comparing Yield Monitors With Weigh Wagons For On-Farm Corn Hybrid Evaluation, Bjorn P. Nelson, Roger Wesley Elmore, Andrew W. Lenssen

Department of Agronomy and Horticulture: Faculty Publications

For many years, on-farm yield evaluations of corn (Zea mays L.) hybrids were done with weigh wagons, handheld moisture testers, and measuring wheels. Today, most combines have continuous flow yield and moisture sensors. Published research results comparing the accuracy of combine-mounted sensor systems with that of weigh wagons are limited for on-farm corn hybrid evaluation. This study examined the accuracy of combine-mounted yield sensors with traditional weigh wagon methodology in on-farm corn hybrid strip trials. Data from combine-mounted sensors for plot weight, moisture percentage, and yield were compared with weigh wagon weight, handheld moisture testers, and calculated yield …

Genetic Engineering Online Lessons Improve Teaching And Increase Knowledge And Accepting Attitudes Among Students, Grace Troupe

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

Genetic engineering has been used in the production of food in the U.S. for nearly three decades, however, science literacy in genetic engineering among consumers is still low. To address this problem, an online resource called The Journey of a Gene (passel.unl.edu/ge) was created to help incorporate genetic engineering education in high school and college curriculums. Here we report two studies conducted to evaluate the effectiveness of The Journey of a Gene in 1) improving student knowledge and attitudes about genetic engineering and 2) helping teachers increase their knowledge as well as quantity and quality of genetic engineering instruction. In …

Photosynthetic Performance And Anti-Oxidative Response Of Cornus Controversa Seedlings Under Cadmium And Lead Stress, Xinyu Huang, Yonglei Jiang, Xiaomao Cheng, Lilan Deng, Xuncheng Liu

Faculty Publications

The photosynthetic efficiency of Cornus controversa leaves was decreased significantly under Cd treatment while it was not affected by Pb exposure. Cd decreased while Pb treatment increased the chlorophyll contents of Cornus controversa leaves. Furthermore, the peroxidase (GPX) activities were decreased after Cd treatment while elevated by Pb exposure in Cornus controvera seedlings. In addition, both Cd and Pb exposures increased the malondialdehyde (MDA) and proline contents and elevated the superoxide dismutase (SOD) activities of Cornus controvera seedlings. Collectively, these results indicated that Cornus controversa may be more tolerant to Pb than Cd toxicity. This finding will contribute to the …

Expressing And Characterizing Mechanosensitive Channels In Xenopus Oocytes, Grigory Maksaev, Elizabeth S. Haswell

Biology Faculty Research

The oocytes of the African clawed frog (Xenopus laevis) comprise one of the most widely used membrane protein expression systems. While frequently used for studies of transporters and ion channels, the application of this system to the study of mechanosensitive ion channels has been overlooked, perhaps due to a relative abundance of native expression systems. Recent advances, however, have illustrated the advantages of the oocyte system for studying plant and bacterial mechanosensitive channels. Here we describe in detail the methods used for heterologous expression and characterization of bacterial and plant mechanosensitive channels in Xenopus oocytes.

Trip: Tracking Rhythms In Plants, An Automated Leaf Movement Analysis Program For Circadian Period Estimation, Kathleen Greenham, Ping Lou, Sara E. Remsen, Hany Farid, C Robertson Mcclung

Dartmouth Scholarship

Background: A well characterized output of the circadian clock in plants is the daily rhythmic movement of leaves. This process has been used extensively in Arabidopsis to estimate circadian period in natural accessions as well as mutants with known defects in circadian clock function. Current methods for estimating circadian period by leaf movement involve manual steps throughout the analysis and are often limited to analyzing one leaf or cotyledon at a time.

Methods: In this study, we describe the development of TRiP (Tracking Rhythms in Plants), a new method for estimating circadian period using a motion estimation algorithm that can …

Environmental Data: Soil Moisture, Julia I. Chapman, Eric B. Borth, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Volumetric soil water content measured on May 2, 2015 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.

Herbaceous 2015, Julia I. Chapman, Margaret E. Maloney, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Herbaceous vegetation data collected in 2015 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.

Heterologous Expression Of Arabidopsis Thaliana Purple Acid Phosphatase Gene (Atpap15) In Crops For Phytoremediation Of Sites Contaminated With Excess Phosphorus, Jane Jeruto Bartonjo

Masters Theses & Specialist Projects

AtPAP15 is one of the purple acid phosphatases expressed by Arabidopsis thaliana that has been extensively studied. Purified AtPAP15 has been shown to exhibit both phytase and phosphomonoesterase activities in acidic pH with maximal activity at pH 4.5. AtPAP15 is a phosphorus starvation inducible (PSI) gene that is expressed highly during phosphorus deficient conditions. In the current study, AtPAP15 was overexpressed in Nicotiana tabaccum under cauliflower mosaic virus (CaMV35S) constitutive promoter. After PCR confirmation of the gene, plants were transferred to the greenhouse and allowed to grow in pots. The pots contained Sta-Green potting mix (Lowe’s Inc., Mooresville, North Carolina,U.S.). …

Phylogenetic Relationships Of Samydaceae And Taxonomic Revision Of The Species Of Casearia In South-Central Asia, Tharangamala Samarakoon

Dissertations

The flowering plant family Samydaceae was recently reinstated to include 14 genera and about 256 species of tropical trees and shrubs. Preliminary analyses of relationships in the family, however, indicated that the largest genus in the family, Casearia, is not monophyletic and that several smaller groups are probably misplaced. In order to affirm or refute those hypotheses, additional DNA sequence data with broader taxon sampling from the Old World were gathered for phylogenetic analysis. In particular, rapidly evolving plastid (matK, ndhF, psbA-trnH, trnL, and trnL-F) and nuclear (EMB2765 and GBSSI) DNA …

Microsatellite Variations Of Elite Setaria Varieties Released During Last Six Decades In China, Guanqing Jia, Xiaotong Liu, James C. Schnable, Zhengang Niu, Chunfang Wang, Yuhui Li, Shujun Wang, Suying Wang, Jinrong Liu, Erhu Guo, Hui Zhi, Xianmin Diao

Department of Agronomy and Horticulture: Faculty Publications

Crop improvement is a multifaceted micro-evolutionary process, involving changes in breeding approaches, planting configurations and consumption preferences of human beings. Recent research has started to identify the specific genes or genomic regions correlate to improved agronomic traits, however, an apparent blank between the genetic structure of crop elite varieties and their improving histories in diverse modern breeding programs is still in existence. Foxtail millet (Setaria italica) was one of the earliest cereal crops to be domesticated and served as a staple crop for early civilizations in China, where it is still widely grown today. In the present trial, …