Life Sciences Commons^™

Integrated Management Strategies For Phytophthora Sojae Combining Host Resistance And Seed Treatments, A. E. Dorrance, A. E. Robertson, S. Cianzo, L. J. Giesler, C. R. Grau, M. A. Draper, A. U. Tenuta, T. R. Anderson

Department of Plant Pathology: Faculty Publications

Phytophthora sojae has re-emerged as a serious soybean pathogen in the past decade. This may be due in part to changes in resistance levels in current cultivars, adoption of P. sojae populations to deployed Rps genes, and highly favorable environments in the past decade. This multilocation study evaluated the effect of seed treatments on the incidence and severity of Phytophthora root and stem rot on soybeans with different combinations of Rps genes and levels of partial resistance. The efficacy of the seed treatments was highly variable across locations. Seed treatments (metalaxyl and mefenoxam) provided protection and increased yields across cultivars …

Joint Fire Science Program – Lake Mead National Recreation Area: Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis, Quarterly Progress Report, October 1 — December 31, 2008, Margaret N. Rees

Fire Science

• Presented poster at Natural Areas Conference in Nashville, TN

• Initiated granivory study at Goodsprings.

• Outplanted 2376 plants for Experiment 1 at Lake Mead nursery.

• Presented poster at Wildfires and Invasive Plants in American Deserts conference in Reno, NV.

• Submitted manuscript covering our distance from road - microsite invasibility study to Journal of Arid Environments.

A High-Oleic-Acid And Low-Palmitic-Acid Soybean: Agronomic Performance And Evaluation As A Feedstock For Biodiesel, George L. Graef, Bradley J. Lavallee, Patrick Tenopir, Mustafa Tat, Bruce Schweiger, Anthony J. Kinney, Jon H. Van Gerpen, Thomas E. Clemente

Department of Agronomy and Horticulture: Faculty Publications

Phenotypic characterization of soybean event 335-13, which possesses oil with an increased oleic acid content (> 85%) and reduced palmitic acid content (< 5%), was conducted across multiple environments during 2004 and 2005. Under these conditions, the stability of the novel fatty acid profile of the oil was not influenced by environment. Importantly, the novel soybean event 335-13 was not compromised in yield in both irrigated and non-irrigated production schemes. Moreover, seed characteristics, including total oil and protein, as well as amino acid profile, were not altered as a result of the large shift in the fatty acid profile. The novel oil trait was inherited in a simple Mendelian fashion. The event 335-13 was also evaluated as a feedstock for biodiesel. Extruded oil from event 335-13 produced a biodiesel with improved cold flow and enhanced oxidative stability, two critical fuel parameters that can limit the utility of this renewable transportation fuel.

Ecotypic Variation In Elymus Elymoides Subspecies Brevifolius Race C In The Northern Intermountain West, Matthew C. Parsons

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Little information is available on the extent of local adaptation for many native grass species. This is the case for squirreltail (Elymus section Sitanion), despite this group's prevalence and importance in rangeland restoration efforts. I evaluated 32 populations of E. elymoides ssp. brevifolius race C, a phylogenetic subdivision of bottlebrush squirreltail (E. elymoides) centered in the northern Intermountain West, for phenotypic variables and neutral genetic markers to measure their association with geographical origin. Phenotypic traits were measured in common field and greenhouse environments, and genetic diversity was assessed using Amplified Fragment Length Polymorphism. Three factors were extracted from the phenotypic …

Aminoglycosides And Syringomycin E As Fungicides Against Fusarium Graminearum In Head Blight Disease, Yukie Kawasaki

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Fusarium graminearum is one of the most problematic phytopathogens in US agriculture. This fungus causes head blight, foot rot, and damping off on wheat and barley. The infection lowers the grain yield and causes contamination of the grain product with mycotoxins. Effective control measures are lacking, and new fungicides that kill F. graminearum but remain safe and economical to use are needed. Newly synthesized aminoglycosides (JL22, JL38, JL39, JL40, NEOF004, NEOF005), classic aminoglycosides (amikacin, gentamicin, kanamycin A, kanamycin B, neomycin, and ribostamycin), and a lipopeptide, syringomycin E (SRE), were studied to determine their antifungal potential to control F. graminearum. …

First Report Of Soybean Rust Caused By Phakopsora Pachyrhizi In Nebraska, S. R. Watson, L. J. Giesler, A. D. Ziems, T. E. Brovont

Department of Plant Pathology: Faculty Publications

Soybean rust caused by Phakopsora pachyrhizi Sydow was first observed in the continental United States in Louisiana in November 2004 (2). As part of the national soybean rust monitoring effort, samples were collected on 3 October 2007 during the scouting of fields with green leaves in southeastern Nebraska. After incubation at room temperature for 24 h, uredinea and urediniospores were observed with microscopic examination. Urediniospores were obovoid, hyaline to pale brown, and measured 20 to 30 × 18 to 20 μm.

Enhanced Plant Nutrient Use Efficiency With Pgpr And Amf In An Integrated Nutrient Management System, A. O. Adesemoye, H. A. Torbert, J. W. Kloepper

Department of Plant Pathology: Faculty Publications

A 3-year field study was conducted with field corn from 2005 to 2007 to test the hypothesis that microbial inoculants that increase plant growth and yield can enhance nutrient uptake, and thereby remove more nutrients—especially N, P, and K—from the field as part of an integrated nutrient management system. The field trial evaluated microbial inoculants, which include a commercially available plant growth-promoting rhizobacteria (PGPR), arbuscular mycorrhiza fungi (AMF), and their combination across 2 tillage systems (no-till and conventional till) and 2 fertilization regimes (poultry litter and ammonium nitrate). Data were collected on plant height, yield (dry mass of ears and …

Joint Fire Science Program – Lake Mead National Recreation Area: Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis, Quarterly Progress Report, July 1 — September 30, 2008, Margaret N. Rees

Fire Science

• Cones monitored and reseeded to obtain plants for nursery study.

• Goodsprings revegetation studies monitored.

• Website developed for JFS study.

• Writing short communication for Journal of Arid Environments.

• Working on poster for NAA conference in October.

The Very-Long-Chain Hydroxy Fatty Acyl-Coa Dehydratase Pasticcino2 Is Essential And Limiting For Plant Development, Liên Bach, Louise V. Michaelson, Richard Haslam, Yannick Bellec, Lionel Gissot, Jessica Marion, Marco Da Costa, Jean-Pierre Boutin, Martine Miquel, Frédérique Tellier, Frederic Domergue, Jennifer E. Markham, Frederic Beaudoin, Johnathan A. Napier, Jean-Denis Faure

Department of Biochemistry: Faculty Publications

Very-long-chain fatty acids (VLCFAs) are synthesized as acyl-CoAs by the endoplasmic reticulum-localized elongase multiprotein complex. Two Arabidopsis genes are putative homologues of the recently identified yeast 3-hydroxy-acyl-CoA dehydratase (PHS1), the third enzyme of the elongase complex. We showed that Arabidopsis PASTICCINO2 (PAS2) was able to restore phs1 cytokinesis defects and sphingolipid long chain base overaccumulation. Conversely, the expression of PHS1 was able to complement the developmental defects and the accumulation of long chain bases of the pas2–1 mutant. The pas2–1 mutant was characterized by a general reduction of VLCFA pools in seed storage triacylglycerols, cuticular waxes, …

Shrub-Interspace Dynamics Alter Relationships Between Microbial Community Composition And Belowground Ecosystem Characteristics, Rebecca E. Drenovsky, Z. T. Aanderud, M. I. Shuldman, J. H. Richards

Biology

In desert ecosystems, belowground characteristics are influenced chiefly by the formation and persistence of “shrub-islands of fertility” in contrast to barren plant interspaces. If soil microbial communities are exclusively compared between these two biogeochemically distinct soil types, the impact of characteristics altered by shrub species, especially soil C and N, are likely to be overemphasized and overshadow the role of other characteristics in structuring microbial composition. To determine how belowground characteristics influence microbial community composition, and if the relative importance of these characteristics shifts across the landscape (i.e., between and within shrub and interspace soils), changes in microbial communities across …

Gender Variation In The Prezygotic Reproductive Effort Of The Common Silver Moss, Kimberley Horsley, Lloyd Stark

Undergraduate Research Opportunities Program (UROP)

The bryophyte Bryum argenteum is a vigorous moss with a cosmopolitan distribution and high tolerance to desiccation and temperature stress. Due to its widespread nature, B. argenteum has been highly investigated (e.g., Chopra and Bhatla 1981). However, very little research has been done on the reproductive aspects of this moss with respect to gender differences. This project will address the prefertilization reproductive efforts of the moss, and look for any differences in the rate of growth and sexual expression between the sexes. The hypothesis to be tested is that males actually have a higher prefertilization reproductive effort than females and …

Decoding The Protein Interaction Network - An Approach Integrating Biology And Math, Ryan Huang, Lingkun Gu, Qingxi J. Shen

Undergraduate Research Opportunities Program (UROP)

The WRKY super family is known to play a major role during the plant stress response and development. My project focuses on the protein-protein interaction of an Oryzasativa (rice) transcription factor, OsWRKY71 which functions as the repressor of gibberellins signaling pathway. Previous literature revealed that OsWRKY71 can interact with itself or OsWRKY51 to form dimmers by using bimolecular fluorescence complementation (BiFC). To confirm this result, we use yeast two-hybrid system. As our data showed, OsWRKY71 seems to suppress the reporter gene expression of the conventional yeast two-hybrid system, so we use a modified yeast two-hybrid, Mating-based Split Ubiquitin System (MbSUS). …

Transcriptional Responses Of Arabidopsis Thaliana Plants To As (V) Stress, Jason M. Abercrombie, Matthew D. Halfhill, Priya Ranjan, Murali R. Rao, Arnold M. Saxton, Joshua S. Yuan, Neal Stewart

Plant Sciences Publications and Other Works

Background

Arsenic is toxic to plants and a common environmental pollutant. There is a strong chemical similarity between arsenate [As (V)] and phosphate (Pi). Whole genome oligonucleotide microarrays were employed to investigate the transcriptional responses of Arabidopsis thaliana plants to As (V) stress.

Results

Antioxidant-related genes (i.e. coding for superoxide dismutases and peroxidases) play prominent roles in response to arsenate. The microarray experiment revealed induction of chloroplast Cu/Zn superoxide dismutase (SOD) (at2g28190), Cu/Zn SOD (at1g08830), as well as an SOD copper chaperone (at1g12520). On the other hand, Fe SODs were strongly repressed in response to As (V) stress. Non-parametric rank …

Phytopathogen Type Iii Effector Weaponry And Their Plant Targets, Anna Block, Guangyong Li, Zheng Qing Fu, James R. Alfano

Center for Plant Science Innovation: Faculty and Staff Publications

Phytopathogenic bacteria suppress plant innate immunity and promote pathogenesis by injecting proteins called type III effectors into plant cells using a type III protein secretion system. These type III effectors use at least three major strategies to alter host responses. One strategy is to alter host protein turnover, either by direct cleavage or by modulating ubiquitination and targeting to the 26S proteasome. Another strategy involves alteration of RNA metabolism by transcriptional activation or ADP-ribosylation of RNA-binding proteins. A third major strategy is to inhibit the kinases involved in plant defence signalling, either by removing phosphates or by direct inhibition. The …

Nectar Secondary Compounds Affect Self-Pollen Transfer: Implications For Female And Male Reproduction, Rebecca E. Irwin, Lynn S. Adler

Dartmouth Scholarship

Pollen movement within and among plants affects inbreeding, plant fitness, and the spatial scale of genetic differentiation. Although a number of studies have assessed how plant and floral traits influence pollen movement via changes in pollinator behavior, few have explored how nectar chemical composition affects pollen transfer. As many as 55% of plants produce secondary compounds in their nectar, which is surprising given that nectar is typically thought to attract pollinators. We tested the hypothesis that nectar with secondary compounds may benefit plants by encouraging pollinators to leave plants after visiting only a few flowers, thus reducing self-pollen transfer. We …

Genetic Diversity In Native And Invasive Rubus (Rosaceae), Ashley A. Wint

Masters Theses & Specialist Projects

Invasive species are an increasing threat to biological diversity as well as a leading cause of recent species’ extinctions. Invasives spread quickly and efficiently, and the U.S spends millions of dollars annually in the control and eradication of these species. More information is necessary in order to predict which species may become invasive. Rubus (Rosaceae) was chosen for study because this genus includes various ploidy levels, reproductive modes, and species that are invasive as well as native.

Three Rubus species were chosen to represent apomictic and tetraploid invasives (Rubus armeniacus), a sexual and diploid native species (R. occidentalis), and a …

"Effect Of Transplant Age, Tobacco Cultivar, Acibenzolar-S-Methyl, And Imidacloprid On Tomato Spotted Wilt Infection In Flue-Cured Tobacco", Claudia Nischwitz

All Current Publications

No abstract provided.

Spiderworts: Not Just Another Pretty Face For Science, W. John Hayden

Biology Faculty Publications

Species of Tradescantia, or spiderworts, are handsome plants. Several wild species, including the VNPS wildflower of the Year for 2008 (T. virginiana), can be found in eastern North America and additional species grace gardens, and hothouse conservatories. Spiderworts are not, however, just a bunch of pretty faces. Spiderworts have a long history of service to science, both in terms of teaching and pure research.

Sphingolipid Long-Chain Base Hydroxylation Is Important For Growth And Regulation Of Sphingolipid Content And Composition In Arabidopsis, Ming Chen, Jennifer E. Markham, Charles R. Dietrich, Jan G. Jaworski, Edgar B. Cahoon

Department of Biochemistry: Faculty Publications

Sphingolipids are structural components of endomembranes and function through their metabolites as bioactive regulators of cellular processes such as programmed cell death. A characteristic feature of plant sphingolipids is their high content of trihydroxy long-chain bases (LCBs) that are produced by the LCB C-4 hydroxylase. To determine the functional significance of trihydroxy LCBs in plants, T-DNA double mutants and RNA interference suppression lines were generated for the two Arabidopsis thaliana LCB C-4 hydroxylase genes Sphingoid Base Hydroxylase1 (SBH1) and SBH2. These plants displayed reductions in growth that were dependent on the content of trihydroxy LCBs in sphingolipids. …

Joint Fire Science Program – Lake Mead National Recreation Area: Revegetating Burned Arid Lands: Identifying Successful Native Species Using Trait And Competition Analysis: Quarterly Progress Report, April 1— June 30, 2008, Margaret N. Rees

Fire Science

• Cones seeded for competition experiment at Lake Mead nursery.

• Cones monitored for seedling establishment.

• Goodsprings revegetation studies monitored.

• Invasibility data being entered and analyzed.

• Abstract for NAA conference submitted.

• Joint Fire Science update article submitted to Mojave Applied Ecology Notes newsletter.

The Effect Of Ginseng On Biofilm Formation By Wild Type And Mutant Strains Of Pseudomonas Aeruginosa, Premi Shekar

Morehead State Theses and Dissertations

A thesis presented to the faculty of the College of Science and Technology at Morehead State University in partial fulfillment of the requirements for the Degree of Master of Science by Premi Shekar on June 25, 2008.

Method For Efficient Post Transcriptional Gene Slencing Using Intrinsic Direct Repeat Sequences And Utilization Thereof Infunctional Genomics, Amitava Mitra, Chonglie Ma

Department of Plant Pathology: Faculty Publications

It is well documented that transgenes with inverted repeats can efficiently trigger post-transcriptional gene silencing (PTGS), presumably via a double stranded RNA induced by complementary sequences in their transcripts. We show here that transgenes with intrinsic direct repeats can also induce PTGS at a very high frequency (80-100%). A transgene with three or four repeats induced PTGS in almost 100% of the primary transformants, regardless of whether a strong (en hanced 35S promoter) or a relatively weak (chlorophyll a?b binding protein promoter) promoter was used. The PTGS induced by three or four repeats is consistently inherited in Subsequent generations, and …

An Antibiotic Complex From Lysobacter Enzymogenes Strain C3: Antimicrobial Activity And Role In Plant Disease Control, S. Li, C. C. Jochum, F. Yu, K. Zaleta-Rivera, L. Du, Steven D. Harris, Gary Y. Yuen

Department of Plant Pathology: Faculty Publications

Lysobacter enzymogenes C3 is a bacterial biological control agent that exhibits antagonism against multiple fungal pathogens. Its antifungal activity was attributed in part to lytic enzymes. In this study, a heat-stable antifungal factor (HSAF), an antibiotic complex consisting of dihydromaltophilin and structurally related macrocyclic lactams, was found to be responsible for antagonism by C3 against fungi and oomycetes in culture. HSAF in purified form exhibited inhibitory activity against a wide range of fungal and oomycetes species in vitro, inhibiting spore germination, and disrupting hyphal polarity in sensitive fungi. When applied to tall fescue leaves as a partially-purified extract, HSAF at …

Seed Invasion Filters And Forest Fire Severity, Tom R. Cottrell, Paul F. Hessburg, Jonathan A. Betz

Biology Faculty Scholarship

Forest seed dispersal is altered after fire. Using seed traps, we studied impacts of fire severity on timing of seed dispersal, total seed rain, and seed rain richness in patches of high and low severity fire and unburned Douglas-fir (Pseudotsuga menziesii) forests in the Fischer and Tyee fire complexes in the eastern Washington Cascades. Unburned plots had the lowest average seed production. The high severity fire patches in the Fischer Fire Complex had a higher total seed production than low severity fire patches of the same complex. At the Tyee Fire Complex, the total seed production for each …

The Complete Plastid Genome Sequence Of Welwitschia Mirabilis: An Unusually Compact Plastome With Accelerated Divergence Rates, Skip R. Mccoy, Jennifer V. Kuehl, Jeffrey L. Boore, Linda A. Raubeson

All Faculty Scholarship for the College of the Sciences

Background

Welwitschia mirabilis is the only extant member of the family Welwitschiaceae, one of three lineages of gnetophytes, an enigmatic group of gymnosperms variously allied with flowering plants or conifers. Limited sequence data and rapid divergence rates have precluded consensus on the evolutionary placement of gnetophytes based on molecular characters. Here we report on the first complete gnetophyte chloroplast genome sequence, from Welwitschia mirabilis, as well as analyses on divergence rates of protein-coding genes, comparisons of gene content and order, and phylogenetic implications.

Results

The chloroplast genome of Welwitschia mirabilis [GenBank: EU342371] is comprised of 119,726 base pairs and exhibits …

Evaluating Vascular Plant Composition And Species Richness On Horn Island, Mississippi, Using Passive And Active Remote Sensing In Conjunction With Ground Based Measurements, Kelly Lynn Lucas

Dissertations

Barrier island vegetation is subjected to chronic abiotic stressors combined with periodic storm events that favor species adapted to harsh environments. These islands are the first landforms to be affected by changes in coastal subsidence and sea-level rise. Evaluating changes in vegetation is important for understanding the impact of global climate change on coastal environments.

This study assesses vegetation composition and plant species richness on Horn Island, Mississippi using ground data in conjunction with remotely sensed spectral and LIDAR data. The goals of this research are to: 1) classify and map vegetation composition on Horn Island using hyperspectral and LIDAR …

Stomatal Conductance Of Malosma Laurina In Frequently Burned And Non-Frequently Burned Sites, Kamron A. King, Matthew T. Bender, Stephen D. Davis

Featured Research

In the months following the Malibu fires, the fire zones have experienced and abundance of new growth. Among this new growth, there are differences that can be observed when comparing the top of the Malibu hill (frequent fire zone) to the base of the hill (nonfrequent fire zone). As the chaparral resprouted we noticed the behavior of the Malosma laurina in both frequent and non-frequent fire zones and stomatal conductance, height, and water potential were tested for plants in the two varying zones, with plants in the non-frequent fire zone outperforming their counterparts.

Soil Moisture Adjacent The Roots Of Post-Fire Ceanothus Megacarpus And Malosma Laurina, Kristi Holly, Kelly Sayre, Anson Snow

Featured Research

Hydraulic lift is a passive process in which a plant will bring water from subsoil to topsoil levels through its roots. In this experiment, we compared the soil moisture levels in the area surrounding two different chaparral species C. megacarpus, a shallow rooted nonsprouter, and M. laurina, a deep-rooted obligate sprouter, in order to determine the hydraulic lift patterns of chaparral as they regrow after fire. Furthermore, the C. Megacarpus had died due to the Malibu fire, while the M. Laurina was resprouting. Therefore, using a Hydrosense Soil Water Measurement System, we measured soil moisture percentages, and the results showed …

The Effect Of Fire Frequency On The Presence Of Native And Nonnative Species In The Santa Monica Mountains, Bobby Boss, Simone Ross, Taryn Thompson

Featured Research

We surveyed two sites in the Santa Monica Mountains of Southern California that experienced both high and low fire frequency (Figure 1). Our objective was to find out if increased fire frequency allowed for the invasion of non-native species. We collected data on herbaceous coverage and point to plant distance of woody chaparral species. A series of random points were used, and each area was divided up into four equal quadrants using two meter sticks. The individual nearest to the center in each quadrant was then identified and measured. To measure herbaceous coverage, percentages were took of cover of each …

Physiological Performance In Full-Sun Vs. Shaded Post-Fire Malosma Laurina Seedlings, Lindsey A. Murphy, David C. Valencia, Catherine D. Drummond

Featured Research

Post-fire Malosma laurina regenerates both by resprouting and by disseminating seeds. The objective of this study is to assess seedling performance either in full-sunlight or in artificially shaded treatments. By identifying under which conditions Malosma laurina seedlings grow more effectively, one can predict where post-fire M. laurina seedling communities will thrive. The methodology employed throughout this experiment began by covering existing seedlings with shade cloth held by wooden stakes. These treatments were adjacent to full-sun environments; each of which contained at least two Malosma laurina seedlings. Six experimental sites were set up, and the seedlings in question were monitored for …