Life Sciences Commons^™

Determining Effects Of Management Practices On Potato Early Dying And Soil Microbiome And Assessing Risk Of Fungicide Resistance In Verticillium Dahliae, Kedi Li

Electronic Theses and Dissertations

Potato early dying (PED) is a yield-constraining soilborne disease of potato, caused by Verticillium spp. with V. dahliae being the predominant causal agent. Since the pathogen inhabits soil for long periods, PED management aims to reduce the population of V. dahliae in soil. Benzovindiflupyr and azoxystrobin are effective chemicals and frequently used in the control of V. dahliae. In this study, field trials were conducted at Aroostook Farm, Presque Isle, ME in 2019 and 2020. Chemical and biological products have been studied for PED control, and fungicide resistance was also examined. To evaluate fungicide resistance, benzovindiflupyr was characterized on …

Genetic Characterization Of Antimicrobial Activities Of Endophytic Bacteria Burkholderia Strains Ms455 And Ms389, Jiayuan Jia

Theses and Dissertations

Strains MS455 and MS389, endophytic bacteria, were isolated from healthy soybean plant growing adjacent to a patch of plants affected by charcoal rot disease, caused by the fungal pathogen Macrophomina phaseolina. The complete genomes of both strains were sequenced and identified as Burkholderia species Strain MS455 exhibits broad-spectrum antifungal activities against economically important pathogens, including Aspergillus flavus. Random and site-specific mutations were employed in discovery of the genes that share high homology to the ocf gene cluster of Burkholderia contaminans strain MS14, which is responsible for production of the antifungal compound occidiofungin. RNA-seq analysis demonstrated ORF1, a …

Ecological And Morphological Differentiation Among Coi Haplotype Groups In The Plant Parasitic Nematode Species Mesocriconema Xenoplax, Julianne N. Matczyszyn, Timothy Harris, Kirsten S. Powers, Sydney E. Everhart, Thomas O. Powers

Department of Plant Pathology: Faculty Publications

DNA barcoding with the mitochondrial COI gene reveals distinct haplotype subgroups within the monophyletic and parthenogenetic nematode species, Mesocriconema xenoplax. Biological attributes of these haplotype groups (HG) have not been explored. An analysis of M. xenoplax from 40 North American sites representing both native plant communities and agroecosystems was conducted to identify possible subgroup associations with ecological, physiological, or geographic factors. A dataset of 132 M. xenoplax specimens was used to generate sequences of a 712 bp region of the cytochrome oxidase subunit I gene. Maximum-likelihood and Bayesian phylogenies recognized seven COI HG (≥99/0.99 posterior probability/bootstrap value). Species delimitation …

Ecological And Morphological Differentiation Among Coi Haplotype Groups In The Plant Parasitic Nematode Species Mesocriconema Xenoplax, Julianne N. Matczyszyn, Timothy Harris, Kirsten S. Powers, Sydney E. Everhart, Tom Powers

Department of Plant Pathology: Faculty Publications

DNA barcoding with the mitochondrial COI gene reveals distinct haplotype subgroups within the monophyletic and parthenogenetic nematode species, Mesocriconema xenoplax. Biological attributes of these haplotype groups (HG) have not been explored. An analysis of M. xenoplax from 40 North American sites representing both native plant communities and agroecosystems was conducted to identify possible subgroup associations with ecological, physiological, or geographic factors. A dataset of 132 M. xenoplax specimens was used to generate sequences of a 712 bp region of the cytochrome oxidase subunit I gene. Maximum-likelihood and Bayesian phylogenies recognized seven COI HG (≥99/0.99 posterior probability/bootstrap value). Species …

Utility Of Anaerobic Soil Disinfestation For Weed And Disease Management In Solanaceous Vegetable Crops, Gursewak Singh

All Theses

Managing weeds is one of the most challenging aspects of growing specialty crops. Weed control options are limited for specialty crops due to absence of effective herbicide options. The limited current herbicide options risk carryover and damage to subsequent crops. Bacterial wilt is another problem causing significant yield losses in southeast vegetable production. After the termination of methyl bromide due to health and environmental concerns, several other chemical fumigants gained interest, including 1,3-dichloropropene, chloropicrin and metam sodium/potassium. While less toxic to the environment than methyl bromide, these fumigants pose carcinogenic and mutagenic threats. Alternative weed control and diseases management tactics …

Sensitivity Of Soybean And Rice To Dicamba, Owen Wesley France

Graduate Theses and Dissertations

Although the integration of dicamba as a postemergence (POST) herbicide has proven useful in controlling many herbicide-resistant weeds, its damage to soybean at low rates, such as supplied by drift and volatility, has been well-documented. Injury to other crops, such as rice, from off-target movement of dicamba and other commonly used herbicides, such as glyphosate, may also occur. Practical options for mitigating injury and yield loss to soybean and other crops from dicamba off-target movement could prove beneficial if dicamba continues to be used during summer months. Experiments were conducted to determine the effects of multiple agricultural practices, including cultivar …

Palmer Amaranth [Amaranthus Palmeri (S.) Wats.] Resistance To S-Metolachlor In The Mid-Southern Us And S-Metolachlor Dissipation In Soil, Koffi Badou Jeremie Kouame

Graduate Theses and Dissertations

Palmer amaranth [Amaranthus palmeri (S.) Wats.] presents both a high genetic diversity and propensity to evolve resistance to herbicides of several sites-of-action which have made it one of the worst weeds in US agriculture. In Arkansas, Palmer amaranth is resistant to herbicides of seven sites-of-action, which are 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) inhibitor, acetolactate synthase inhibitors, microtubule inhibitors, protoporphyrinogen oxidase inhibitors, very long chain fatty acid inhibitors, glutamine synthetase inhibitors, and hydroxyphenylpyruvate dioxygenase inhibitors. Sustainable management requires a better understanding of its biology and that of herbicide environmental fate. This research had five objectives: 1) characterize the current status of Palmer amaranth …

Mitigating Rice Injury Caused By Florpyrauxifen-Benzyl And Optimizing Florpyrauxifen-Benzyl Rate And Timing For Use In Furrow-Irrigated Rice, James Winston Beesinger

Graduate Theses and Dissertations

Florpyrauxifen-benzyl (synthetic auxin, WSSA Group 4) is a postemergence, broad-spectrum herbicide labeled for use in Mid-South rice (Oryza sativa L.) production. Introduction of florpyrauxifen-benzyl to Arkansas rice production led to observations of varying levels of injury caused by the herbicide across cultivars and environments. Findings from previous research indicated hybrid long-grain rice and medium-grain rice were more susceptible to florpyrauxifen-benzyl and hypotheses were formed using this research regarding the impact of environmental conditions on the amount of injury observed. Concerns of yield loss, delay in maturity and loss of groundcover as well as questions regarding the ability of florpyrauxifen-benzyl to …

Arkansas Soybean Research Studies 2020, Jeremy Ross

Arkansas Agricultural Experiment Station Research Series

The 2020 Arkansas Soybean Research Studies includes research reports on topics pertaining to soybean across several disciplines from breeding to post-harvest processing. Research reports contained in this publication may represent preliminary or only data from a single year or limited results; therefore, these results should not be used as a basis for long-term recommendations. Several research reports in this publication will appear in other University of Arkansas System Division of Agriculture’s Arkansas Agricultural Experiment Station publications. This duplication is the result of the overlap in research coverage between disciplines and our effort to inform Arkansas soybean producers of the research …

Effects Of Nitrogen Management And Cultivar On Strawberry Production Under Disease Pressure, Kamille A. Garcia-Brucher

Master's Theses

Effects of nitrogen management and cultivar on strawberry production under disease pressure

Kamille Garcia-Brucher

California strawberry growers face increasing regulatory pressures to manage nitrogen (N) applications in their production system. Standard practice in the California strawberry industry is to apply a synthetic pre-plant controlled release fertilizer (CRF) to ensure the crop has sufficient N during winter establishment. Some research from the UC Cooperative Extension suggests this practice is not efficient at delivering N to the crop since most of the N is released from CRF before strawberry crop N uptake is significant. Another concern for California strawberry growers is loss …

The Impact Of Beneficial Organisms In Corn Agroecosystems, Callie Rosalind Braley

Doctor of Plant Health Program: Dissertations and Student Research

Corn is one of the world’s, and Nebraska’s, most important crops. Millions of acres are planted to corn each year in the Cornhusker State. However, each year there are a plethora of arthropod, weed, and microorganism pests that rob farmers of reaching their maximum yield potential. There are many options available to manage these pests in corn agroecosystems, but one option is often underutilized: beneficial organisms. For each pest, there are a variety of natural enemies that can assist in mitigating the damage caused by pests.

Many beneficial organisms exist, and they can be grouped by the type of pest …

Identification And Genetic Characterization Of Pseudomonas Syringae Pv. Syringae From Sweet Cherry In Turkey, Cansu Oksel, Farhat A. Avin, Mustafa Mirik, Fulya Baysal-Gurel

Agricultural and Environmental Sciences Faculty Research

Pseudomonas syringae pv. syringae (Pss), which causes bacterial canker, is the most polyphagous bacterium in the P. syringae complex due to its broad host range. This pathogen is considered the major bacterial disease in cherry orchards. In this study, several samples were collected from infected sweet cherry trees in different locations of the Marmara region in Turkey between 2016-2018. Sixty-three isolates were identified as Pss by pathogenicity, LOPAT, GATTa, and MALDI-TOF MS tests. Total genomic DNA was extracted to confirm identity, followed by PCR amplification of syrB and cfl genes. Out of 63 isolates, 12 were randomly selected for Repetitive …

Response Of Roseau Cane (Phragmites Australis) To Two Biotic Stresses: Hyalopterus Pruni And Bipolaris Yamadae, Heather E. Cizek

LSU Master's Theses

Roseau cane (Phragmites australis) is considered an invasive plant because of its ability to replace native plant species. However, in Louisiana it plays an important role protecting coastal infrastructure and being part of the marsh ecosystem in the lower Mississippi River Delta. In recent years, Roseau cane has been affected by a die-off, a problem that has also been reported in some European countries. Possible biotic and abiotic factors that have been associated with the die-off include scale insects, climate change, pollution, salinity levels, and pathogens.

In this research, the individual and combined effect of a foliar disease …

Lily Leaf Beetle, Ann Mull, Lori R. Spears

All Current Publications

The lily leaf beetle (LLB) (Coleoptera: Chrysomelidae) is an important pest from Eurasia that threatens native and cultivated true lilies (Lilium spp.) and fritillaries (Fritillaria spp.). It is also known as the red lily leaf beetle or scarlet lily beetle. LLB was first reported in North America in Montréal, Canada, in 1945 and in the U.S. in 1992 in Massachusetts, likely arriving via European shipments of lily bulbs. LLB has been detected in nine of the 10 Canadian provinces and 14 U.S. states, including the New England states, Pennsylvania, Wisconsin, Minnesota, and Washington (EDDMapS, 2021). Based on LLB’s native distribution …

Global Distribution And Richness Of Armillaria And Related Species Inferred From Public Databases And Amplicon Sequencing Datasets, Rachel A. Koch, Joshua Herr

Department of Plant Pathology: Faculty Publications

Armillaria is a globally distributed fungal genus most notably composed of economically important plant pathogens that are found predominantly in forest and agronomic systems. The genus sensulato has more recently received attention for its role in woody plant decomposition and in mycorrhizal symbiosis with specific plants. Previous phylogenetic analyses suggest that around 50 species are recognized globally. Despite this previous work, no studies have analyzed the global species richness and distribution of the genus using data derived from fungal community sequencing datasets or barcoding initiatives. To assess the global diversity and species richness of Armillaria, we mined publicly available sequencing …

Using Uav Technology Paired With Multispectral Cameras To Assess Crown Rust Epidemics In Oats, Turner A. Graham

LSU Master's Theses

Crown rust, caused by Puccinia cornonata f. sp. avenae, is a common disease of oats (Avena sativa) found virtually everywhere oats are cultivated. This disease has caused yield losses of 10 to 40% worldwide. Early detection is important for effective management. A more recently utilized technology in agriculture is unmanned aerial vehicles (UAVs). UAVs, or drones, equipped with cameras are now being used as a resource to take images of fields to identify pests and other issues that may be occurring. Normalized differentiated vegetative index (NDVI) is a numerical indicator used to determine the vegetative health of …

Hyperspectral Reflectance-Based Phenotyping For Quantitative Genetics In Crops: Progress And Challenges, Marcin Grzybowski, Kuwan K. Wijewardane, Abbas Atefi, Yufeng Ge, James C. Schnable

Center for Plant Science Innovation: Faculty and Staff Publications

Many biochemical and physiological properties of plants that are of interest to breeders and geneticists have extremely low throughput and/or can only be measured destructively. This has limited the use of information on natural variation in nutrient and metabolite abundance, as well as photosynthetic capacity in quantitative genetic contexts where it is necessary to collect data from hundreds or thousands of plants. A number of recent studies have demonstrated the potential to estimate many of these traits from hyperspectral reflectance data, primarily in ecophysiological contexts. Here, we summarize recent advances in the use of hyperspectral reflectance data for plant phenotyping, …

The Role Of Low-Molecular Weight Fungal Metabolites In Eutypa Dieback Grapevine Trunk Disease, Dana Sebestyen

Masters Theses

Eutypa dieback, one of several grapevine trunk diseases (GTDs), is of serious concern to the grape industry globally. This disease is caused by the fungus Eutypa lata but it is often seen in consortia growth with Phaeoacremonium minimum and Phaeomoniella chlamydospora. It is vital to understand the mechanisms for how this disease functions to develop control measures to combat it. Brown rot fungi are able to use a complex of low molecular weight (LMW) metabolites to induce a Fenton reaction to deconstruct woody tissue. These metabolites are part of a chelator mediated Fenton (CMF) chemistry that produces reactive oxygen …

Transcriptomics Reveals The Putative Mycoparasitic Strategy Of The Mushroom Entoloma Abortivum On Species Of The Mushroom Genus Armillaria, Rachel A. Koch, Joshua Herr

Department of Plant Pathology: Faculty Publications

During mycoparasitism, a fungus—the host—is parasitized by another fungus—the mycoparasite. The genetic underpinnings of these relationships have been best characterized in ascomycete fungi. However, within basidiomycete fungi, there are rare instances of mushroom-forming species parasitizing the reproductive structures, or sporocarps, of other mushroom-forming species, which have been rarely investigated on a genetic level. One of the most enigmatic of these occurs between Entoloma abortivum and species of Armillaria, where hyphae of E. abortivum are hypothesized to disrupt the development of Armillaria sporocarps, resulting in the formation of carpophoroids. However, it remains unknown whether carpophoroids are the direct result of a …

Salicylic Acid: A Key Regulator Of Redox Signalling 1 And Plant Immunity, Mohd Saleem, Qazi Fariddudin, Christian Castroverde

Biology Faculty Publications

In plants, the reactive oxygen species (ROS) formed during normal conditions are essential in regulating several processes, like stomatal physiology, pathogen immunity and developmental signaling. However, biotic and abiotic stresses can cause ROS over-accumulation leading to oxidative stress. Therefore, a suitable equilibrium is vital for redox homeostasis in plants, and there have been major advances in this research arena. Salicylic acid (SA) is known as a chief regulator of ROS; however, the underlying mechanisms remain largely unexplored. SA plays an important role in establishing the hypersensitive response (HR) and systemic acquired resistance (SAR). This is underpinned by a robust and …

Automatic Identification And Monitoring Of Plant Diseases Using Unmanned Aerial Vehicles: A Review, Krishna Neupane, Fulya Baysal-Gurel

Agricultural and Environmental Sciences Faculty Research

Disease diagnosis is one of the major tasks for increasing food production in agriculture. Although precision agriculture (PA) takes less time and provides a more precise application of agricultural activities, the detection of disease using an Unmanned Aerial System (UAS) is a challenging task. Several Unmanned Aerial Vehicles (UAVs) and sensors have been used for this purpose. The UAVs’ platforms and their peripherals have their own limitations in accurately diagnosing plant diseases. Several types of image processing software are available for vignetting and orthorectification. The training and validation of datasets are important characteristics of data analysis. Currently, different algorithms and …

Identification Of Bacterial Wilt (Erwinia Tracheiphila) Resistances In Usda Melon Collection, Bimala Acharya, Lucas Mackasmiel, Ali Taheri, Christine A. Ondzighi-Assoume, Yiqun Weng, C. Korsi Dumenyo

Agricultural and Environmental Sciences Faculty Research

Bacterial wilt (BW) caused by the Gram-negative bacterium, Erwinia tracheiphila (Et.), is an important disease in melon (Cucumis melo L.). BW-resistant commercial melon varieties are not widely available. There are also no effective pathogen-based disease management strategies as BW-infected plants ultimately die. The purpose of this study is to identify BW-resistant melon accessions in the United States Department of Agriculture (USDA) collection. We tested 118 melon accessions in two inoculation trials under controlled environments. Four-week-old seedlings of test materials were mechanically inoculated with the fluorescently (GFP) labeled or unlabeled E. tracheiphila strain, Hca1-5N. We recorded the number of days to …

A Phytobacterial Tir Domain Effector Manipulates Nad+ To Promote Virulence, Samuel Eastman, Thomas Smith, Mark A. Zaydman, Panya Kim, Samuel Martinez, Neha Damaraju, Aaron Diantonio, Jeffrey Milbrandt, Thomas E. Clemente, James R. Alfano, Ming Guo

Department of Plant Pathology: Faculty Publications

• The Pseudomonas syringae DC3000 type III effector HopAM1 suppresses plant immunity and contains a Toll/interleukin-1 receptor (TIR) domain homologous to immunity-related TIR domains of plant nucleotide-binding leucine-rich repeat receptors that hydrolyze nicotinamide adenine dinucleotide (NAD⁺) and activate immunity. In vitro and in vivo assays were conducted to determine if HopAM1 hydrolyzes NAD⁺ and if the activity is essential for HopAM1’s suppression of plant immunity and contribution to virulence.
• HPLC and LC-MS were utilized to analyze metabolites produced from NAD⁺ by HopAM1 in vitro and in both yeast and plants. Agrobacterium-mediated transient expression and in planta …

Influence Of Planting Date, Maturity Group, Harvest Aids And Fungicide Application On Soybean (Glycine Max (L.) Seed Quality, Ana Priscila Campos

LSU Master's Theses

Field studies evaluated the influence of planting date, maturity group, and harvest timing on soybean yield and seed quality at the LSU AgCenter Northeast (NERS), Macon Ridge, and Dean Lee Research Stations in 2018-2020. In addition, the influence of harvest aid and fungicide application on seed quality impact from delayed harvest and environment was investigated at NERS in 2019 and 2020 in both field and environmentally controlled growth chambers. Soybean yield was maximized when maturity group IV and V soybean varieties were planted between Mid-April and Mid-May. Earlier and later planting dates did not result in maximized yield. Planting date …

Understanding The Etiology Of Taproot Decline Of Soybean Caused By Xylaria Necrophora, José E. Ortiz Solórzano

LSU Master's Theses

Taproot decline (TRD) of soybean is caused by Xylaria necrophora. However, the mechanisms by which it infects soybean and produces symptoms are unknown. Symptoms of TRD include foliar interveinal chlorosis and necrosis and root necrosis, yet X. necrophora appears to be restricted to the roots. While Xylaria species are predominantly wood decomposers, a few are pathogens. More importantly, they produce secondary metabolites (SMs) with multiple bioactivities, including phytotoxicity and antimicrobial activity. Preliminary experiments suggested that X. necrophora was producing SMs responsible for TRD symptoms. We evaluated cell-free culture filtrates (CFs) for phytotoxicity on soybeans, testing for changes in chlorophyll …

Optimization Of Dna Extraction From Difficult Sandy-Loam Soils, Anka Colo

Undergraduate Student Research Internships Conference

Ginseng is a high value perennial crop grown for its roots. A four-year cultivation cycle is required to obtain marketable ginseng roots, during which a condition called ginseng replant disease (GRD) develops. GRD is characterized by a severe root rot disease, and prevents the growth of newly planted ginseng in a former ginseng garden1. Microbiome analysis of ginseng garden soil will help our understanding of the formation of GRD and its severity. However, extracting DNA from the sandy-loam soils required for ginseng cultivation is difficult. Commercial kits are either too expensive or not applicable to the large volumes of soil …

Primary Industries Development Research Highlights 2021, Department Of Primary Industries And Regional Development, Tim Scanlon

Books & book chapters

The Primary Industries Development Research Highlights 2021 showcases the breadth and depth of the Department of Primary Industries and Regional Development’s research and development activities over the past several years.

Stories featured in Research Highlights 2021 stem from about 60 (of 140) current and recently-completed projects undertaken by the Department of Primary Industries and Regional Development’s (DPIRD) 1100 scientists, technical experts and economists throughout the State.

Explore our Research Highlights 2021.

The publication demonstrates the innovative and applicable research that DPIRD and its collaborators and investment partners deliver to Western Australia.

Download the Research Highlights 2021 here. Alternatively, …

Powdery Mildews On Vegetables, Nick Volesky, Marion Murray, Claudia Nischwitz

All Current Publications

Powdery mildew is one of the most easily recognized fungal plant diseases. It is categorized by spots or patches of white-to-gray powder-like growth on foliage, stems, or fruit. Roughly 700 species exist that infect grasses, ornamentals, weeds, fruit trees, landscape trees, shrubs, and vegetables. The closely related species of fungi that cause powdery mildew are host-specific, meaning they cannot survive without the proper host. Powdery mildew fungi spread in conditions of low rainfall and hot temperatures, making Utah’s climate the perfect environment. This fact sheet provides information on powdery mildew and its management.

Telomere Roles In Fungal Genome Evolution And Adaptation, Mostafa Rahnama, Baohua Wang, Jane Dostart, Olga Novikova, Daniel Yackzan, Andrew T. Yackzan, Haley Bruss, Maray Baker, Haven Jacob, Xiaofei Zhang, April Lamb, Alex Stewart, Melanie Heist, Joey Hoover, Patrick Calie, Li Chen, Jinze Liu, Mark L. Farman

Plant Pathology Faculty Publications

Telomeres form the ends of linear chromosomes and usually comprise protein complexes that bind to simple repeated sequence motifs that are added to the 3′ ends of DNA by the telomerase reverse transcriptase (TERT). One of the primary functions attributed to telomeres is to solve the “end-replication problem” which, if left unaddressed, would cause gradual, inexorable attrition of sequences from the chromosome ends and, eventually, loss of viability. Telomere-binding proteins also protect the chromosome from 5′ to 3′ exonuclease action, and disguise the chromosome ends from the double-strand break repair machinery whose illegitimate action potentially generates catastrophic chromosome aberrations. Telomeres …

B.R. Wells Arkansas Rice Research Studies 2020, J. Hardke, X. Sha, N. Bateman

Arkansas Agricultural Experiment Station Research Series

Arkansas is the leading rice producer in the United States. The state represents 47.5% of total U.S. rice production and 48.1% of the total acres planted to rice in 2020. Rice cultural practices vary across the state and across the U.S. However, these practices are also dynamic and continue to evolve in response to changing political, environmental, and economic times. This survey was initiated in 2002 to monitor and record changes in the way Arkansas rice producers approach their livelihood. The survey was conducted by polling county extension agents in each of the counties in Arkansas that produce rice. Questions …