Plant Biology Commons^™

Effect Of Temperature On Wheat Streak Mosaic Disease Development In Winter Wheat, Everlyne N. Wosula, Satyanarayana Tatineni, Stephen N. Wegulo, Gary L. Hein

Department of Plant Pathology: Faculty Publications

Temperature is one of the key factors that influence viral disease development in plants. In this study, temperature effect on Wheat streak mosaic virus (WSMV) replication and in planta movement was determined using a green fluorescent protein (GFP)-tagged virus in two winter wheat cultivars. Virus-inoculated plants were first incubated at 10, 15, 20, and 25°C for 21 days, followed by 27°C for 14 days; and, in a second experiment, virus-inoculated plants were initially incubated at 27°C for 3 days, followed by 10, 15, 20, and 25°C for 21 days. In the first experiment, WSMV-GFP in susceptible ‘Tomahawk’ wheat at 10°C …

Detection And Characterization Of Xanthomonas Vasicola Pv. Vasculorum (Cobb 1894) Comb. Nov. Causing Bacterial Leaf Streak Of Corn In The United States, J. M. Lang, E. Ducharme, J. Ibarra Caballero, E. Luna, T. Hartman, M. Ortiz-Castro, K. A. Korus, J. Rascoe, T. A. Jackson-Ziems, K. Broders, J. E. Leach

Department of Plant Pathology: Faculty Publications

Bacterial leaf streak of corn (Zea mays) recently reached epidemic levels in three corn-growing states and has been detected in another six states in the central United States. Xanthomonas vasicola was identified as the causal agent of this disease. A multilocus sequence alignment of six housekeeping genes and comparison of average nucleotide identity from draft genome sequence were used to confirm phylogenetic relationships and classification of this bacteria relative to other X. vasicola strains. X. vasicola isolates from Nebraska and South Africa were highly virulent on corn and sugarcane and less virulent on sorghum but caused water-soaking symptoms …

Plant Disease Management, Tamra A. Jackson-Ziems, Anthony O. Adesemoye, Loren J. Giesler, Robert M. Harveson, Stephen N. Wegulo, Joshua J. Miller, James D. Harbour

Department of Plant Pathology: Faculty Publications

Fungicides are an important component of the pesticide program for some Nebraska fields. While not all fields of corn, dry bean, sorghum, soybean, sugarbeet, sunflower, and wheat will require a fungicide application, it’s critical that you know the correct product for the disease in your field when you do need it.

Identification. The first step with any disease management program is to make sure you have correctly identified the problem. Identification is critical as there are many bacterial diseases with symptoms similar to fungal diseases, and fungicides will have no activity on them. For help identifying crop diseases, visit the …

What's New In Plant Pathology, Joshua J. Miller, Anthony O. Adesemoye, Loren Giesler, Robert M. Harveson, Tamra A. Jackson-Ziems, Stephen N. Wegulo, James D. Harbour, Terra Hartman

Department of Plant Pathology: Faculty Publications

Changes to the Disease Management Section of the 2017 Guide for Weed, Disease, and Insect Management in Nebraska

Bacterial Leaf Streak of Corn—An Emerging Disease in Nebraska and First Report in the United States

Pest and Plant Diagnostic Clinic Position Change

New Products … Ethos XB … Majestene

Table 1. Foliar products for disease control that were updated in the 2017 Guide for Weed, Disease, and Insect Management in Nebraska

Table 2. Seed treatment products for disease control that were updated in the 2017 Guide for Weed, Disease, and Insect Management in Nebraska

Table 3. Biological products that were updated …

Response Of Sorghum Stalk Pathogens To Brown Midrib Plants And Soluble Phenolic Extracts From Near Isogenic Lines, Deanna L. Funnell-Harris, Patrick M. O'Neill, Scott E. Sattler, Tammy Gries, Mark A. Berhow, Jeffrey F. Pedersen

Department of Plant Pathology: Faculty Publications

Sorghum [Sorghum bicolor (L.) Moench] has drawn attention as potential feedstock for lignocellulosic biofuels production, and reducing lignin is one way to increase conversion efficiency. Little research has been previously conducted to assess the response of reduced lignin sorghum lines to the Fusarium stalk rot pathogens Fusarium verticillioides and Fusarium proliferatum and the charcoal rot pathogen, Macrophomina phaseolina. Loss of function mutations in either the Brown midrib (Bmr) 6 or 12 gene that both encode a monolignol biosynthetic enzyme in the pathway that produces subunits of the lignin polymer, results in reduced lignin content. Near-isogenic bmr6, …

Best Practices For Population Genetic Analyses, Niklaus J. Grünwald, Sydney E. Everhart, B. J. Knaus, Z. N. Kamvar

Department of Plant Pathology: Faculty Publications

Population genetic analysis is a powerful tool to understand how pathogens emerge and adapt. However, determining the genetic structure of populations requires complex knowledge on a range of subtle skills that are often not explicitly stated in book chapters or review articles on population genetics. What is a good sampling strategy? How many isolates should I sample? How do I include positive and negative controls in my molecular assays? What marker system should I use? This review will attempt to address many of these practical questions that are often not readily answered from reading books or reviews on the topic, …

Phenotypic And Genotypic Characterization Of Relevant Sclerotinia Sclerotiorum Isolates, Thomas J. Justo Miorini, Anthony G. Pannullo, T. Hornby, Robert Higgins, Sydney E. Everhart, James R. Steadman

Department of Plant Pathology: Faculty Publications

Knowledge of pathogen population structure is useful to identify isolates for screening cultivars and lines for resistance. For S. sclerotiorum, causal agent of white mold in more than 400 plant species, including common bean and soybean, breeding for resistance is particularly challenging. The objective of this study was to characterize phenotypic and genotypic variation of S. sclerotiorum isolates from soybean production areas of the U.S.A. (15), Brazil (75), and Argentina (5) to compare them with 366 isolates from dry bean characterized previously (Everhart et al., 2016).

Best Practices For Population Genetic Analyses, Niklaus J. Grünwald, Sydney E. Everhart, B. J. Knaus, Zhian N. Kamvar

Department of Plant Pathology: Faculty Publications

Population genetic analysis is a powerful tool to understand how pathogens emerge and adapt. However, determining the genetic structure of populations requires complex knowledge on a range of subtle skills that are often not explicitly stated in book chapters or review articles on population genetics. What is a good sampling strategy? How many isolates should I sample? How do I include positive and negative controls in my molecular assays? What marker system should I use? This review will attempt to address many of these practical questions that are often not readily answered from reading books or reviews on the topic, …

Control Of White Mold Of Dry Bean And Residual Activity Of Fungicides Applied By Chemigation, Thomas J.J. Miorini, Carlos G. Raetano, Sydney E. Everhart

Department of Plant Pathology: Faculty Publications

Sclerotinia sclerotiorum is a necrotrophic fungal pathogen that causes white mold of dry bean (Phaseolus vulgaris L.). Chemigation with fungicides is used for disease control, but effectiveness of this application method and impact of irrigation level on residual fungicide activity in the plant over time under field conditions has not been well characterized. To assess the best method of application and fungicide for disease control, we conducted field studies in three field sites in São Paulo State in Brazil. Contact fungicide, fluazinam, was applied via center pivot at three irrigation levels (2.5, 5.1, 10.1 mm) at the Itaí field …

Glucose-Abl1-Tor Signaling Modulates Cell Cycle Tuning To Control Terminal Appressorial Cell Differentiation, Margarita Marroquin-Guzman, Guangchao Sun, Richard Wilson

Department of Plant Pathology: Faculty Publications

The conserved target of rapamycin (TOR) pathway integrates growth and development with available nutrients, but how cellular glucose controls TOR function and signaling is poorly understood. Here, we provide functional evidence from the devastating rice blast fungus Magnaporthe oryzae that glucose can mediate TOR activity via the product of a novel carbon- responsive gene, ABL1, in order to tune cell cycle progression during infection-related development. Under nutrient-free conditions, wild type (WT) M. oryzae strains form terminal plant-infecting cells (appressoria) at the tips of germ tubes emerging from three-celled spores (conidia). WT appressorial development is accompanied by one round …

Comparative Leaf Anatomy Of C3 And Cam Species In Oncidiinae (Maxillarieae, Orchidaceae), Samuel A. Eident

Masters Theses

The subtribe Oncidiinae is a diverse group of mostly epiphytic orchids within the tribe Maxillarieae, consisting of 55 genera and 1700 species. In this group, there have been many studies examining morphological and anatomical variation as well as metabolic pathways of carbon fixation, but most have not integrated morphological and anatomical variation with a physiological aspect of inquiry. The objective of my research was to establish a suite of anatomical characteristics that can be used to distinguish between C₃ and CAM species. Secondarily, I hoped to use that suite of characteristics in determining whether intermediate CAM species (those that …

Elucidation Of Abscisic Acid In Stress Resistance Of Mnium Cuspidatum Through Salt Exposure And Chlorophyll Content Analysis, Kurt Corsbie

Undergraduate Honors Thesis Collection

Upon exposure to stresses, a battery of reactions occurs within the model moss Physcomitrella patens that induces the expression of defense-related genes. One of these reactions results in the production of abscisic acid (ABA), a plant hormone that helps a plant resist desiccation by inducing the activation of defense genes which results in protective physiological reactions. In this study, experiments were conducted on the moss species Mnium cuspidatum to see if it responds similarly to P. patens. This comparison was investigated as sample groups of M. cuspidatum and P. patens were pre-treated with 0µM, 50µM, or 500µM ABA to …

1980 Lilley Cornett Woods Soil Data, Ryan W. Mcewan, Julia I. Chapman, Robert N. Muller

Data Files: Big Everidge Hollow Permanent Plots

Data collected in 1980 on the soil in the Big Everidge Hollow portion of the Lilley Cornett Woods Appalachian Ecological Research Station in southeastern Kentucky. Data key is provided in a supplemental file.

DOI: https://doi.org/10.26890/lcw.4b97vlypkk

1979 Lilley Cornett Woods Overstory Data, Ryan W. Mcewan, Julia I. Chapman, Robert N. Muller

Data Files: Big Everidge Hollow Permanent Plots

Data collected in 1979 on the overstory in the Big Everidge Hollow portion of the Lilley Cornett Woods Appalachian Ecological Research Station in southeastern Kentucky. Data key is provided in a supplemental file.

Accompanying photo by Julia I. Chapman.

DOI: https://doi.org/10.26890/lcw.s2qvt68sox

Robust Spatial Frameworks For Leveraging Research On Sustainable Crop Intensification, Patricio Grassini, Cameron M. Pittelkow, Kenneth Cassman, Haishun S. Yang, Sotirios Archontoulis, Mark Licht, Kendall R. Lamkey, Ignacio A. Ciampitti, Jeffrey A. Coulter, Sylvie M. Brouder, Jeffrey J. Volenec, Noemi Guindin-Garcia

Department of Agronomy and Horticulture: Faculty Publications

Meeting demand for food, fiber, feed, and fuel in a world with 9.7 billion people by 2050 without negative environmental impact is the greatest scientific challenge facing humanity. We hypothesize that this challenge can only be met with current and emerging technologies if guided by proactive use of a broad array of relevant data and geospatial scaling approaches to ensure local to global relevance for setting research priorities and implementing agricultural systems responsive to real-time status of weather, soils, crops, and markets. Despite increasing availability of field-scale agricultural data, robust spatial frameworks are lacking to convert these data into actionable …

The Effects Of Elevated Co2 Levels On Broad Bean, Vicia Faba, Growth/Defense Tradeoffs, Harley B. Kitching

Honors College Theses

Atmospheric changes, associated with global climate change, are increasing at an unprecedented rate. Plants generally display higher rates of growth in response to elevated CO₂ levels, but this response varies among species. In addition, very little is known about how plant growth/defense tradeoffs will be altered by increasing CO₂ levels. By raising Broad bean, Vicia faba L., plants under ambient (400 ppm) and elevated (900 ppm) levels of CO₂, it was shown that atmospheric composition directly altered plant growth/defense tradeoffs. Plants grown under elevated CO₂ had lighter stem weights but greater numbers of extrafloral nectaries …

Micro-Spectroscopy Of Bio-Assemblies At The Single Cell Level, Jeslin Kera

Honors Undergraduate Theses

In this thesis, we investigate biological molecules on a micron scale in the ultraviolet spectral region through the non-destructive confocal absorption microscopy. The setup involves a combination of confocal microscope with a UV light excitation beam to measure the optical absorption spectra with spatial resolution of 1.4 μm in the lateral and 3.6 μm in the axial direction. Confocal absorption microscopy has the benefits of requiring no labels and only low light intensity for excitation while providing a strong signal from the contrast generated by the attenuation of propagating light due to absorption. This enables spatially resolved measurements of single …

Sexual Dimorphism In The Moss Bryum Argenteum And Its Implications For Sex Ratio Bias, Jonathan David Moore Iii

Theses and Dissertations--Biology

In dioecious plants, selection due to sex function differences has produced sex-specific life histories, morphologies, and physiologies. In many dioecious seed plants, dimorphisms and population sex ratios have been plausibly linked, but similar links are not yet apparent in dioecious bryophytes. Population sex ratio bias is often expected to favor the sex with lower investment in sexual reproduction, especially in resource-poor environments. Unlike in seed plants, bryophyte males may have higher average reproductive investment than females, which typically have low offspring production rates due to sperm limitation. However, traits aside from reproductive investment such as shoot and leaf arrangement may …

Column Key, Big Everidge Hollow Permanent Plots, Ryan W. Mcewan, Julia I. Chapman, Robert N. Muller

Data Files: Big Everidge Hollow Permanent Plots

Column key for .csv data files.

Accompanying photo by Julia I. Chapman.

DOI: https://doi.org/10.26890/lcw.rx26w6rcvs

2010 Lilley Cornett Woods Overstory Data, Ryan W. Mcewan, Julia I. Chapman, Robert N. Muller

Data Files: Big Everidge Hollow Permanent Plots

Data collected in 2010 on the overstory in the Big Everidge Hollow portion of the Lilley Cornett Woods Appalachian Ecological Research Station in southeastern Kentucky. Data key is provided in a supplemental file.

Accompanying photo by Julia I. Chapman.

DOI: https://doi.org/10.26890/lcw.s3l6btsgv3

1999 Lilley Cornett Woods Overstory Data, Ryan W. Mcewan, Julia I. Chapman, Robert N. Muller

Data Files: Big Everidge Hollow Permanent Plots

Data collected in 1999 on the overstory in the Big Everidge Hollow portion of the Lilley Cornett Woods Appalachian Ecological Research Station in southeastern Kentucky. Data key is provided in a supplemental file.

Accompanying photo by Ryan W. McEwan.

DOI: https://doi.org/10.26890/lcw.5pn95oc6d7

1989 Lilley Cornett Woods Overstory Data, Ryan W. Mcewan, Julia I. Chapman, Robert N. Muller

Data Files: Big Everidge Hollow Permanent Plots

Data collected in 1989 on the overstory in Big Everidge Hollow portion of the Lilley Cornett Woods Appalachian Ecological Research Station in southeastern Kentucky. Data key is provided in a supplemental file.

Accompanying photo by Ryan W. McEwan.

DOI: https://doi.org/10.26890/lcw.jt5ds3db92

Overstory 2017, Mitchell J. Kukla, Corey M. Kuminecz, Julia I. Chapman, Taylor M. Sparbanie, Katherine Schrader, Michelle N. Little, Keith E. Gilland, Ryan W. Mcewan

Data Files: Drew Woods Permanent Plots

Overstory data (woody species ≥2.5 centimeters in diameter at breast height) collected in 2017 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.

Saplings 2017, Mitchell J. Kukla, Corey M. Kuminecz, 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 2017 at Drew Woods State Nature Preserve in Darke County, OH. Data key is provided in a supplemental file.

Are Weevils Picky Eaters? Community Structure And Host Specificity Of Neotropical Saproxylic Beetles (Coleoptera: Curculionidae), Jhunior A. Morillo

Dissertations and Theses

Abstract Primary saproxylic beetles play a major role in forest nutrient cycling and making deadwood accessible to other decomposers. Understanding beetle host preferences and patterns of community assembly is critical for their conservation, and for predicting which species might become invasive. This project aims to investigate the ecological and host specificity, as well as the community composition of curculionids in a mosaic of old-growth (OG) and secondary forest on the Osa Peninsula, Costa Rica. The subfamily Scolytinae was expected to be the most species-rich and abundant. Ambrosia beetles were expected to have more generalist species than other curculionids. Old growth …

Influence Of Topography And Moisture And Nutrient Availability On Green Alder Function On The Low Arctic Tundra, Nt, Katherine Louise Black Ms., Jennifer Lynn Baltzer Dr.

Theses and Dissertations (Comprehensive)

The Arctic has warmed by at least 3^°C over the past 50 years and this rapid warming is expected to continue. Climate warming is driving the proliferation of shrubs across the tundra biome with implications for energy balance, climate, hydrology, nutrient cycling, and biodiversity. Changes in tundra plant water use attributable to shrub expansion are predicted to increase evapotranspirative water loss which may amplify local warming and reduce run-off. However, little is known about the extent to which shrubs will enhance evapotranspirative water loss in these systems. Direct measures of shrub water use are needed to accurately predict …

The Effect Of Artificial Selection On Phenotypic Plasticity In Maize, Joseph L. Gage, Diego Jarquin, Cinta Romay, Aaron Lorenz, Edward S. Buckler, Shawn Kaeppler, Naser Alkhalifah, Martin Bohn, Darwin A. Campbell, Jode Edwards, David Ertl, Sherry Flint-Garcia, Jack Gardiner, Byron Good, Candice N. Hirsch, Jim Holland, David C. Hooker, Joseph Knoll, Judith Kolkman, Greg Kruger, Nick Lauter, Carolyn J. Lawrence-Dill, Elizabeth Lee, Jonathan Lynch, Seth C. Murray, Rebecca Nelson, Jane Petzoldt, Torbert Rocheford, James C. Schnable, Patrick S. Schnable, Brian Scully, Margaret Smith, Nathan M. Springer, Srikant Srinivasan, Renee Walton, Teclemariam Weldekidan, Randall J. Wisser, Wenwei Xu, Jianming Yu, Natalia De Leon

Department of Agronomy and Horticulture: Faculty Publications

Remarkable productivity has been achieved in crop species through artificial selection and adaptation to modern agronomic practices. Whether intensive selection has changed the ability of improved cultivars to maintain high productivity across variable environments is unknown. Understanding the genetic control of phenotypic plasticity and genotype by environment (G × E) interaction will enhance crop performance predictions across diverse environments. Here we use data generated from the Genomes to Fields (G2F) Maize G × E project to assess the effect of selection on G × E variation and characterize polymorphisms associated with plasticity. Genomic regions putatively selected during modern temperate maize …

Allelic Variants Of Oshkt1;1 Underlie The Divergence Between Indica And Japonica Subspecies Of Rice (Oryza Sativa) For Root Sodium Content, Malachy T. Campbell, Nonoy Bandillo, Fouad Razzaq A. Al Shiblawi, Sandeep Sharma, Kan Liu, Qian Du, Aaron J. Schmitz, Chi Zhang, Anne-Alienor Very, Aaron J. Lorenz, Harkamal Walia

Department of Agronomy and Horticulture: Faculty Publications

Salinity is a major factor limiting crop productivity. Rice (Oryza sativa), a staple crop for the majority of the world, is highly sensitive to salinity stress. To discover novel sources of genetic variation for salt tolerance-related traits in rice, we screened 390 diverse accessions under 14 days of moderate (9 dS m^-1) salinity. In this study, shoot growth responses to moderate levels of salinity were independent of tissue Na⁺ content. A significant difference in root Na+ content was observed between the major subpopulations of rice, with indica accessions displaying higher root Na⁺ and japonica …

Jasmonoyl-L-Tryptophan Disrupts Iaa Activity Through The Aux1 Auxin Permease, Paul E. Staswick, Martha Rowe, Edgar P. Spalding, Bessie L. Splitt

Department of Agronomy and Horticulture: Faculty Publications

Amide-linked conjugates between tryptophan (Trp) and jasmonic (JA) or indole-3- acetic (IAA) acids interfered with gravitropism and other auxin-dependent activities in Arabidopsis, but the mechanism was unclear. To identify structural features necessary for activity several additional Trp conjugates were synthesized. The phenylacetic acid (PAA) conjugate was active, while several others were not. Common features of active conjugates is that they have ring structures that are linked to Trp through an acetic acid side chain, while longer or shorter linkages are inactive or less active. A dominant mutant, called tryptophan conjugate response1-D that is insensitive to JA-Trp, but still sensitive …

Tgbs® Genotyping-By-Sequencing Enables Reliable Genotyping Of Heterozygous Loci, Alina Ott, Sanzhen Liu, James C. Schnable, Cheng-Ting 'Eddy' Yeh, Kai-Sin Wang, Patrick S. Schnable

Department of Agronomy and Horticulture: Faculty Publications

Conventional genotyping-by-sequencing (cGBS) strategies suffer from high rates of missing data and genotyping errors, particularly at heterozygous sites. tGBS® genotyping-by-sequencing is a novel method of genome reduction that employs two restriction enzymes to generate overhangs in opposite orientations to which (single-strand) oligos rather than (double-stranded) adaptors are ligated. This strategy ensures that only doubledigested fragments are amplified and sequenced. The use of oligos avoids the necessity of preparing adaptors and the problems associated with inter-adaptor annealing/ligation. Hence, the tGBS protocol simplifies the preparation of high-quality GBS sequencing libraries. During polymerase chain reaction (PCR) amplification, selective nucleotides included at the 3'-end …