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Proceedings Of The 46th Annual Meeting Of The Southern Soybean Disease Workers (March 6-7, 2019, Pensacola Beach, Florida), Carl Bradley, Heather M. Kelly, Burt Bluhm, Danise Beadle, Patricia Bollich, Trey Price, Tom Allen

Southern Soybean Disease Workers: Conference Proceedings

Contents

List of SSDW Officers

Agenda for March 6-7, 2019

Abstracts for presented/contributed papers

Evaluating phytotoxicity in response to fungicide by adjuvant combinations. TW Allen and TH Wilkerson

Effect of delayed harvest on the seed quality of commercial soybean cultivars. JC Rupe, JA Rojas, R Holland, SR Segalin, RD Bond, and JA Still

Virome of Macrophomina phaseolina isolates collected from soybean fields in Mississippi. Nina Aboughanem-Sabanadzovic, Tessie Wilkerson, Tom Allen, and Sead Sabanadzovic

Genomic evidence for interspecific hybridization in Cercospora cf. flagellaris strains associated with Cercospora leaf blight of soybean. Alex Zaccaron, Kona Swift, Ahmad Fakhoury, and Burt Bluhm

Identification …

Global Responses Of Resistant And Susceptible Sorghum (Sorghum Bicolor) To Sugarcane Aphid (Melanaphis Sacchari), Hannah M. Tetreault, Sajjan Grover, Erin Scully, Tammy Gries, Nathan A. Palmer, Gautam Sarath, Joe Louis, Scott E. Sattler

Department of Entomology: Faculty Publications

The sugarcane aphid (Melanaphis sacchari) has emerged as a significant pest for sorghum. The use of sugarcane aphid-resistant sorghum germplasm with integrated pest management strategies appears to be an excellent solution to this problem. In this study, a resistant line (RTx2783) and a susceptible line (A/BCK60) were used to characterize the differences in plant responses to the sugarcane aphid through a series of experiments, which examined global sorghum gene expression, aphid feeding behavior and inheritance of aphid resistance. The global transcriptomic responses to sugarcane aphids in resistant and susceptible plants were identified using RNA-seq and compared to the …

Good To The Last Drop: The Emergence Of Coffee Ringspot Virus, Michael Goodin, Antonia Dos Reis Figueira

Plant Pathology Faculty Publications

Two and a half billion times per day a human hand reaches for a fresh cup of coffee. Although arguably dispensable for life per se, with an industry value of US$174 billion, coffee provides the lifeblood that sustains economies of producing countries located in the “coffee belt” situated between the Tropics of Cancer and Capricorn. As a “solvent” in which many human interactions take place, coffee is witness to the broad spectrum of human activities from the mundane to the pleasurable and personal. However, in opposition to its economic, cultural, and physiological importance, diseases such as coffee rust (caused by …

Investigations Into Aspergillus Flavus Infection Of Corn And Regulation Of Aflatoxin Production By Volatiles And Biocontrol Strains, Rebecca R. Sweany

LSU Doctoral Dissertations

Aspergillus flavus is an ascomycete fungus impacting agriculture, public and environmental health due to production of acutely-toxic, carcinogenic aflatoxins in oil seed crops, especially corn in Louisiana, and lung infections of immunocompromised patients resulting in a leading cause of AIDS patients’ deaths globally. The most effective aflatoxin mitigation strategy, biocontrol by atoxigenic A. flavus presents several concerns including: dissemination of a human pathogen, possible sexual reproduction and reliance on precise environmental conditions. Several aspects of A. flavus biology were investigated to potentially improve treatments. Studies investigated how genotypically diverse members within the A. flavus population interact with other population members …

The N-Glycan Structures Of The Antigenic Variants Of Chlorovirus Pbcv-1 Major Capsid Protein Help To Identify The Virus-Encoded Glycosyltransferases, Immacolata Speciale, Garry A. Duncan, Luca Unione, Irina Agarkova, Domenico Garozzo, Jesus Jimenez-Barbero, Sicheng Lin, Todd L. Lowary, Antonio Molinaro, Eric Noel, Maria Elena Laugieri, Michela Tonetti, James L. Van Etten, Cristina De Castro

James Van Etten Publications

The chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1) is a large dsDNA virus that infects the microalga Chlorella variabilis NC64A. Unlike most other viruses, PBCV-1 encodes most, if not all, of the machinery required to glycosylate its major capsid protein (MCP). The structures of the four N-linked glycans from the PBCV-1 MCP consist of nonasaccharides, and similar glycans are not found elsewhere in the three domains of life. Here, we identified the roles of three virus-encoded glycosyltransferases (GTs) that have four distinct GT activities in glycan synthesis. Two of the three GTs were previously annotated as GTs but the third …

Identification Of Climate And Genetic Factors That Control Fat Content And Fatty Acid Composition Of Theobroma Cacao L. Beans, Guiliana M. Mustiga, Joe Morrissey, Joseph Conrad Stack, Ashley Duval, Stefan Royaert, Johannes Jansen, Carolina Bizzotto, Cristiano Villela-Dias, Linkai Mei, Edgar B. Cahoon, Ed Seguine, Jean Philippe Marelli, Juan Carlos Motamayor

Center for Plant Science Innovation: Faculty Publications

The main ingredients of chocolate are usually cocoa powder, cocoa butter, and sugar. Both the powder and the butter are extracted from the beans of the cacao tree (Theobroma cacao L.). The cocoa butter represents the fat in the beans and possesses a unique fatty acid profile that results in chocolate’s characteristic texture and mouthfeel. Here, we used a linkage mapping population and phenotypic data of 3,292 samples from 420 progeny which led to the identification of 27 quantitative trait loci (QTLs) for fatty acid composition and six QTLs for fat content. Progeny showed extensive variation in fat levels …

Drought-Responsive Genes, Late Embryogenesis Abundant Group3 (Lea3) And Vicinal Oxygen Chelate, Function In Lipid Accumulation In Brassica Napus And Arabidopsis Mainly Via Enhancing Photosynthetic Efficiency And Reducing Ros, Yu Liang, Kai Kang, Lu Gan, Shaobo Ning, Jinye Xiong, Shuyao Song, Lingzhi Xi, Senying Lai, Yongtai Yin, Jianwei Gu, Jun Xiang, Shisheng Li, Baoshan Wang, Maoteng Li

Center for Plant Science Innovation: Faculty Publications

Drought is an abiotic stress that affects plant growth, and lipids are the main economic factor in the agricultural production of oil crops. However, the molecular mechanisms of drought response function in lipid metabolism remain little known. In this study, overexpression (OE) of different copies of the drought response genes LEA3 and VOC enhanced both drought tolerance and oil content in Brassica napus and Arabidopsis. Meanwhile, seed size, membrane stability and seed weight were also improved in OE lines. In contrast, oil content and drought tolerance were decreased in the AtLEA3 mutant (atlea3) and AtVOC-RNAi of Arabidopsis and in both …

Fad2 Gene Radiation And Positive Selection Contributed To Polyacetylene Metabolism Evolution In Campanulids1[Open], Tao Feng, Ya Yang, Lucas Busta, Edgar B. Cahoon, Hengchang Wang, Shiyou Lü

Center for Plant Science Innovation: Faculty Publications

Polyacetylenes (PAs) are bioactive, specialized plant defense compounds produced by some species in the eudicot clade campanulids. Early steps of PA biosynthesis are catalyzed by Fatty Acid Desaturase 2 (FAD2). Canonical FAD2s catalyze desaturation, but divergent forms can catalyze hydroxylation, conjugation, acetylenation, and epoxygenation. These alternate reactions give rise to valuable unusual fatty acids, including the precursors to PAs. The extreme functional diversity of FAD2 enzymes and the origin of PA biosynthesis are poorly understood from an evolutionary perspective. We focus here on the evolution of the FAD2 gene family. We uncovered a core eudicot-wide gene duplication event giving rise …

Two Distinct Nucleic Acid Binding Surfaces Of Cdc5 Regulate Development, Chao Wang, Mu Li, Guorui Li, Wensheng Zhao, Bin Yu, Junfeng Liu, Jun Yang, You-Liang Peng

Center for Plant Science Innovation: Faculty Publications

Cell division cycle 5 (Cdc5) is a highly conserved nucleic acid binding protein among eukaryotes and plays critical roles in development. Cdc5 can simultaneously bind to DNA and RNA by its N- terminal DNA-binding domain (DBD), but molecular mechanisms describing its nucleic acid recognition and the regulation of development through its nucleic acid binding remain unclear. Herein, we present a crystal structure of the N-terminal DBD of MoCdc5 (MoCdc5-DBD) from the rice blast fungus Magnaporthe oryzae. Residue K100 of MoCdc5 is on the periphery of a positively charged groove that is formed by K42, K45, R47, and N92 and is …

Comprehensive Analysis Of Aspergillus Nidulans Pka Phosphorylome Identifies A Novel Mode Of Crea Regulation, Liliane F. C. Ribeiro, Cynthia Chelius, Karthik R. Boppidi, Nisha S. Naik, Simin Hossain, Jessica J. J. Ramsey, Jyothi Kumar, Lucas F. Ribeiro, Marc Ostermeier, Bao Tran, Young Ah Goo, Leandro J. De Assis, Mevlut Ulas, Ozgur Bayram, Gustavo H. Goldman, Stephen Lincoln, Ranjan Srivastava, Steven D. Harris, Mark R. Marten

Center for Plant Science Innovation: Faculty Publications

In filamentous fungi, an important kinase responsible for adaptation to changes in available nutrients is cyclic AMP (cAMP)-dependent protein kinase (protein kinase A [PKA]). This kinase has been well characterized at a molecular level, but its systemic action and direct/indirect targets are generally not well understood in filamentous fungi. In this work, we used a pkaA deletion strain (ΔpkaA) to identify Aspergillus nidulans proteins for which phosphorylation is dependent (either directly or indirectly) on PKA. A combination of phosphoproteomic and transcriptomic analyses revealed both direct and indirect targets of PKA and provided a global perspective on its function. …

Manipulation Of Β-Carotene Levels In Tomato Fruits Results In Increased Aba Content And Extended Shelf-Life, Gianfranco Diretto, Sarah Frusciante, Claudia Fabbri, Nicolas Schauer, Lucas Busta, Zhonghua Wang, Antonio J. Matas, Alessia Fiore, Jocelyn K. C. Rose, Alisdair R. Fernie, Reinhard Jetter, Benedetta Mattei, Jim Giovannoni, Giovanni Giuliano

Center for Plant Science Innovation: Faculty Publications

Tomato fruit ripening is controlled by the hormone ethylene and by a group of transcription factors, acting upstream of ethylene. During ripening, the linear carotene lycopene accumulates at the expense of cyclic carotenoids. Fruit-specific overexpression of LYCOPENE β-CYCLASE (LCYb) resulted in increased β-carotene (provitamin A) content. Unexpectedly, LCYb-overexpressing fruits also exhibited a diverse array of ripening phenotypes, including delayed softening and extended shelf life. These phenotypes were accompanied, at the biochemical level, by an increase of abscisic acid (ABA) content, decreased ethylene production, increased density of cell wall material containing linear pectins with a low degree of …

Strain-Specific Protein Interaction And Localization Of Two Strains Of Potato Yellow Dwarf Virus And Functional Domains Of Their Matrix Protein, Chanyong Jang

Theses and Dissertations--Plant Pathology

Potato yellow dwarf virus (PYDV) is the type species of the genus nucleorhabdovirus which is typified by its nucleotropic characters of the members. The virus accomplishes its replication and morphogenesis in the nuclei of infected cells. Two strains, Constricta strain (CYDV) and Sanguinolenta strain (SYDV) have been described at the level of vector-specificity. CYDV is vectored by Agallia constricta and SYDV is transmitted by Aceratagllia sanguinolenta. The full-length genome of CYDV was sequenced. The 12,792 nt antisense genome encodes seven open reading frames in the order of, nucleocapsid protein (N), unknown protein (X), phosphoprotein (P), movement protein (Y), matrix …

Chloroviruses Lure Hosts Through Long-Distance Chemical Signaling, David Dunigan, Maitham Ahmed Al-Sammak, Zeina Al-Ameeli, Irina Agarkova, John Delong, James L. Van Etten

James Van Etten Publications

Chloroviruses exist in aquatic systems around the planet where they infect certain eukaryotic green algae that are mutualistic endosymbionts in a variety of protists and metazoans. Natural chlorovirus populations are seasonally dynamic but the precise temporal changes in these populations and the mechanisms that underlie them have, heretofore, been unclear. We recently reported the novel concept that predator/prey-mediated virus activation regulates chlorovirus population dynamics, and in the current manuscript demonstrate virus packaged chemotactic modulation of prey behavior.

Viruses have not previously been reported to act as chemotactic/chemo-attractive agents. Rather, viruses as extracellular entities are generally viewed as non-metabolically active spore-like …

Some Studies On Leaf Spot Of Oats And Triticale, Mohammed Abdullah Lashram

Electronic Theses and Dissertations

Oat is an important cereal crop, and it is considered to be among the highest used in cereal crops. It is considered among the healthiest grains due to the rich source of the soluble fiber, β-glucan that helps in lowering the cholesterol. Oat production and demand have increased considerably in the past few years due to its health benefits. South Dakota is ranked in the top three largest oat-producing states in the USA. Oat is relatively less susceptible to pest and diseases except for leaf diseases such as crown rust, Drechslera avenae leaf spot, and Stagonospora avenae leaf blotch. Leaf …

Species Of Fusarium Causing Root Rot Of Soybean In South Dakota: Characterization, Pathogenicity, And Interaction With Heterodera Glycines, Paul Nyawanda Okello

Electronic Theses and Dissertations

In South Dakota, Fusarium-associated diseases (e.g. seedling diseases, root rot and sudden death syndrome) are emerging threats to soybean production. Several species of Fusarium have been reported to cause these diseases in the soybean producing regions of the United States and in the world. However, little information is available on the species of Fusarium causing soybean root rot in South Dakota and their pathogenicity. Therefore, the objectives of this study were to (1) characterize the species of Fusarium causing soybean root rot in South Dakota; (2) evaluate the cross-pathogenicity of species of Fusarium causing root rot of soybean and corn; …

Efficacy Of Synthetic And Biopesticides On Bacteria Leaf Streak Management And Influence Of Cultivar And Environment On Epiphytic Bacteria Diversity On Wheat Seeds, Marilen Nampijja

Electronic Theses and Dissertations

Wheat (Triticum aestivum) is the most important staple food for over two billion people, or 36% of the world population. The United States ranks 4th in the world for wheat production. However, wheat production is faced by both biological and non-biological constraints. Among the biological constraints, diseases play a big role in limiting wheat production with estimated yield losses ranging from 20% to 40%. Bacterial leaf streak (BLS) of wheat caused by Xanthomonas translucens pv undulosa (Xtpvu) is one of the major bacterial diseases affecting the wheat production in most wheat growing regions in the USA. In recent years, it …

Optimization Of Engineered Super Donor Strains Of Cryphonectria Parasitica To Reduce Canker Expansion In A Forest Setting, Amy Michelle Metheny

Graduate Theses, Dissertations, and Problem Reports (ETD)

Chestnut blight, caused by the non-native fungus Cryphonectria parasitica, has decimated American chestnut (Castanea dentata) populations throughout the eastern U.S. over the last century. Biological control of blight, termed hypovirulence, has emerged naturally in the form of a debilitating hypovirus transmitted through hyphal anastomosis among vegetatively compatible C. parasitica strains. Six unlinked vegetative incompatibility (vic) loci regulate hyphal anastomosis and thus, hypovirus transmission, which has limited biocontrol efficacy in genotypically diverse communities. Recently, four of six vic loci have been disrupted to engineer two “super donor” or SD strains. In combining these strains, enhanced transmission …

Genetic Regulation Of The Elicitation Of Glyceollin Biosynthesis In Soybean, Md. Asraful Jahan

Graduate Theses, Dissertations, and Problem Reports (ETD)

Glyceollin phytoalexins are the pathogen-elicited defense metabolites that belong to the isoflavonoid family of molecules of soybean (Glycine max L. Merr). Phytophthora root and stem rot of soybean caused by Phytophthora sojae is a destructive disease throughout the soybean-growing regions worldwide causing devastating economic damages (globally $1-2 billion and over $250 million in the USA) every year. Engineering soybean plants that produce higher levels of glyceollins could confer resistance against this pathogen. Glyceollins also show anticancer and neuroprotective activities in mammals, therefore they are important for agriculture and medical research. Firstly, we were interested in understanding how biotic and …

A Small Viral Potassium Ion Channel With An Inherent Inward Rectification, Denise Eckert, Tobias Schulze, Julian Stahl, Oliver Rauh, James L. Van Etten, Brigitte Hertel, Indra Schroeder, Anna Moroni, Gerhard Thiel

Department of Plant Pathology: Faculty Publications

Some algal viruses have coding sequences for proteins with structural and functional characteristics of pore modules of complex K⁺ channels. Here we exploit the structural diversity among these channel orthologs to discover new basic principles of structure/function correlates in K⁺ channels. The analysis of three similar K⁺ channels with ≤ 86 amino acids (AA) shows that one channel (Kmp_v1) generates an ohmic conductance in HEK293 cells while the other two (Kmpv_SP1, Kmpv_PL1) exhibit typical features of canonical Kir channels. Like Kir channels, the rectification of the viral channels is a function …

Cryopreservation Of Paramecium Bursaria Chlorella Virus-1 During An Active Infection Cycle Of Its Host, Samantha R. Coy, Alyssa N. Alsante, James L. Van Etten, Steven W. Wilhelm

Department of Plant Pathology: Faculty Publications

Best practices in laboratory culture management often include cryopreservation of microbiota, but this can be challenging with some virus particles. By preserving viral isolates researchers can mitigate genetic drift and laboratory-induced selection, thereby maintaining genetically consistent strains between experiments. To this end, we developed a method to cryopreserve the model, green-alga infecting virus, Paramecium bursaria Chlorella virus 1 (PBCV-1). We explored cryotolerance of the infectivity of this virus particle, whereby freezing without cryoprotectants was found to maintain the highest infectivity (~2.5%). We then assessed the cryopreservation potential of PBCV-1 during an active infection cycle in its Chlorella variabilis NC64A host, …

When Viruses Infect Plants, Hernan Garcia-Ruiz

Department of Plant Pathology: Faculty Publications

Just as human beings can catch a cold, plants can also get viral infections. Understanding the mechanisms regulating the interactions between plants and viruses is the first step towards developing better management strategies and using biotechnology methods to immunise plants and engineer genetic resistance to viruses in plants. This is the focus of research by Dr Hernan Garcia-Ruiz and his team based at the University of Nebraska, USA.

Viral diseases in plants can cause important economic losses as a result of poor-quality products and lower yield. This impact can particularly seriously affect developing countries which are more likely to be …

Host Factors Against Plant Viruses, Hernan García-Ruiz

Department of Plant Pathology: Faculty Publications

Plant virus genome replication and movement is dependent on host resources and factors. However, plants respond to virus infection through several mechanisms, such as autophagy, ubiquitination, mRNA decay and gene silencing, that target viral components. Viral factors work in synchrony with pro-viral host factors during the infection cycle and are targeted by antiviral responses. Accordingly, establishment of virus infection is genetically determined by the availability of the pro-viral factors necessary for genome replication and movement, and by the balance between plant defence and viral suppression of defence responses. Sequential requirement of pro-viral factors and the antagonistic activity of antiviral factors …

Disease Resistance In Wheat And Its Relatives, Ethan James Andersen

Electronic Theses and Dissertations

Plants have evolved a complex defense system against pests and pathogens utilizing many types of receptors, signaling factors, and defense compounds to detect pathogen presence and respond effectively. Since many pathogens have evolved immunesuppressing effectors used to reduce plant resistance, plants have evolved a family of receptors that detect pathogenic effectors as a result of an evolutionary arms race. These receptors contain Nucleotide-Binding Site and Leucine-Rich Repeat domains and are called NBS-LRR or NLR proteins. Many grasses possess huge genomes with hundreds of NLR-encoding genes, often found in clusters at the extra-pericentromeric regions of chromosomes, where unequal crossing over causes …

Characterizing Spatiotemporal Patterns Of White Mold In Soybean Across South Dakota Using Remote Sensing, Confiance L. Mfuka

Electronic Theses and Dissertations

Soybean is among the most important crops, cultivated primarily for beans, which are used for food, feed, and biofuel. According to FAO, the United States was the biggest soybeans producer in 2016. The main soybean producing regions in the United States are the Corn Belt and the lower Mississippi Valley. Despite its importance, soybean production is reduced by several diseases, among which Sclerotinia stem rot, also known as white mold, a fungal disease that is caused by the fungus Sclerotinia sclerotiorum is among the top 10 soybean diseases. The disease may attack several plants and considerably reduce yield. According to …

Morphological And Phylogenetic Resolution Of Diplodia Spp., Emerging Canker Pathogens Of Oak (Quercus Spp.), In The United States, Savannah Lyn Ferreira

Graduate Theses, Dissertations, and Problem Reports (ETD)

In Mediterranean Europe and the United States, oak species (Quercus spp.) have been in a state of declining health and vigor for the past several decades. Several biotic agents have been found to contribute to this decline to varying degrees including Phytophthora cinnamomi and Armillaria spp., both causal agents of root rots, and various insect defoliators. In the U.S., Bretziella fagacearum, the causal agent of oak wilt, has also been implicated. More recently, Diplodia corticola (Dc) and other Diplodia spp. have been implicated in causing dieback and mortality of oak species in Europe and in …