Plant Pathology Commons^™

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; …

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 …

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 …

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 …

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, …

Peningkatan Produktivitas Tanaman Kedelai Kultivar Anjasmoro Asal Benih Terdeteriorasi Dengan Kompos Trichoderma Dan Bokashi, Sumadi, Denny Sobardini Sobarna, Pujawati Suryatmana, Meddy Rachmadi, Erni Suminar

Jurnal Kultivasi

Trichoderma spp merupakan golongan fungi yang bersifat antipatogen, khususnya layu kecambah, sedangkan bokashi merupakan kompos yang diperkaya dengan beberapa mikroba yang bermanfaat bagi pertumbuhan tanaman.Tulisan ini merupakan rangkuman penelitian pot menggunakan kompos Trichoderma spp sebagai pelapis benih terdeteriorasi disertai bokashi kotoran hewan yang dilakukan pada tanah lahan kering dan tanah sawah pada tahun 2014 dan 2017. Percobaan pertama membandingkan efektivitas beberapa agen hayati sebagai pelapis benih pengaruhnya terhadap vigor benih dan hasil tanaman. Hasil percobaan menunjukkan penggunaan kompos Trichoderma hasilnya lebih baik dibandingkan agen hayati lainnya. Hasil percobaan selanjutnya menunjukkan bahwa pelapisan benih dengan 1 sampai 3 g kompos Trichoderma …

Potensi Metabolit Sekunder Gulma Sebagai Pestisida Nabati Di Indonesia, Koko Tampubolon, Fransisca Natalia Sihombing, Zavandri Purba, Sony Tri Septian Samosir, Syahibal Karim

Jurnal Kultivasi

Tujuan kajian ilmiah ini adalah untuk mengetahui manfaat dan mekanisme metabolit sekunder gulma, kelebihan dan kekurangan pestisida nabati gulma, identifikasi metabolit sekunder gulma, prosedur pembuatan pestisida nabati dari gulma, dan implikasi kebijakan dari pestisida nabati gulma dalam mengendalikan organisme pengganggu tanaman. Hasil kajian menunjukkan potensi senyawa metabolit sekunder dari gulma dapat berfungsi ganda sebagai pestisida nabati. Kelebihan pestisida nabati dari gulma antara lain: (1) metabolit sekunder gulma bersifat organik dan tidak bersifat racun, (2) gulma yang digunakan mudah diperoleh dari lapangan dan tidak membutuhkan biaya yang mahal, (3) beberapa mekanisme metabolit sekunder gulma tidak ditemui dalam mekanisme kerja pestisida sintetis, …

Defining The Genetic Regulation Of Appressorium Formation In Cercospora Zeae-Maydis, Hazel Apiyo Buyu

Graduate Theses and Dissertations

Cercospora zeae-maydis is one of the primary pathogens associated with gray leaf spot, one of the most damaging foliar diseases of maize in the world. Gray leaf spot can be managed to some extent by cultural practices and fungicide applications. To infect maize, C. zeae-maydis grows towards stomata and forms infectious structures, termed appressoria, over stomatal pores. Prior research on the pathogen revealed that appressorium formation is crucial for foliar infection. Although several genes involved in pathogenesis have been identified in C. zeae-maydis, the molecular regulation of appressorium formation in this pathogen is poorly understood. Specifically, how the fungus senses …

Molecular Basis Of Pathogenesis And Host Determination In Cercospora Sojina: From Phenotypic To Genotypic Patterns, Wagner Calegari Fagundes

Graduate Theses and Dissertations

Frogeye leaf spot (FLS), caused by Cercospora sojina, is an important and recurrent disease of soybean in many production regions. Genetic resistance is potentially one of the most cost-effective and sustainable strategies to control FLS. However, C. sojina has already demonstrated the ability to overcome resistance conveyed by single R-genes (resistance genes) of soybeans, followed by the emergence of new physiological races. Although understanding population genomics and the virulence gene inventories in fungal plant pathogens is extremely important to improve disease control measures, studies regarding host specificity and pathogenesis in C. sojina are very limited. Therefore, the overarching goal of …

Understanding And Predicting Nematode Damage On Soybean Using Spatially Weighted Analysis, Barry Boney

Graduate Theses and Dissertations

Aerial imagery offers great potential as a predictive scouting method and could allow growers to better understand crop performance over time. Evidence suggests that the seed treatments fluopyram and abamectin result in decreased reproduction and root galling by Meloidogyne incognita, but yield protection in fields with higher or different nematode pressure is unclear. The objective of this work was to determine the efficacy of these seed treatments compared to 1,3-dichloropropene (1,3-D) applied site-specifically and then predict where these might best be applied to other fields. In a soybean field infested with M. incognita, apparent electrical conductivity was highly correlated with …

Epidemiological Studies Of Soybean Vein Necrosis Virus And Potential Resistance Mechanisms To Its Vector Neohydatothrips Variabilis (Beach), Jing Zhou

Graduate Theses and Dissertations

Soybean (Glycine max (L.) Merrill) is one the most important crops in global agriculture with annual production of over 260 million metric tons. As the dependence of a growing global population to soybean has increased, so does the importance of soybean diseases and pests. Over 200 pathogens attack soybean; among them, viruses pose a major threat to the soybean industries accounting for approximately 10% of the annual yield reduction caused by diseases in the past two decades. Soybean vein necrosis virus (SVNV) is a relatively newly discovered virus causing the homonymous disease. The widespread occurrence of the disease in major …

Impact Of Roadside Maintenance Practices On Larinus Minutus (Gyllenhal), A Biological Control Agent Of Spotted Knapweed, Mary Elizabeth Ferguson

Graduate Theses and Dissertations

Spotted knapweed, Centaurea stoebe, is an invasive weed found throughout much of the United States. Spotted knapweed is a rangeland weed where it was originally introduced into western North America in the 1880s.Where spotted knapweed spread to the southeastern U.S., it is found mostly along roadsides. It has been the focus of a biological control program beginning in the 1960s, with 12 insects established, with the final introductions occurring in the 1990s. After the success observed in the western U.S. and Canada with one of these insects, Larinus minutus, this weevil was established in northwestern Arkansas. It is too early …

Where Are All Of Arkansas' Chinquapins? An Ecological Assessment Of Castanea Throughout The State, Logan Pierce Estes

Graduate Theses and Dissertations

Around the turn of the twentieth-century, the chestnut blight fungus (Cryphonectria parasitica) was accidentally introduced into North America. This strong pathogen, which specializes on trees of the genus Castanea, spread rapidly and within half a century had nearly extirpated North America’s Castanea natives from their ranges. During this catastrophe, the American chestnut (Castanea dentata) garnered much of the scientific attention, pushing the other Castanea natives – the chinquapins – to the wayside. More than a century following the spread of the blight, little research into the ecology of North America’s chinquapins had been performed, leaving these trees significantly underrepresented. The …

Efficacy Of Antimicrobial Mitigation On Escherichia Coli Cfu And Growth And Development Of Hydroponic Leafy Greens, Nathan J. Eylands

Graduate Theses and Dissertations

The Food and Drug Administration (FDA) have set new standards that apply to agriculturalists producing crops eaten fresh and/or raw by consumers. This new produce safety rule, known as the Food Safety Modernization Act (FSMA), has established science-based standards for all areas of production in agriculture with regards to microbial contamination. Escherichia coli (E. coli) O157:H7 is a particular bacterium of concern under FSMA guidelines. Grower compliance is mandatory and therefore vital to the continuation of any farm. Greenhouse hydroponic growers have shown advantages in efficiency when compared to conventional farming methodology. Those, however, with recirculating hydroponic systems face unique …

Evaluation Of Rice Stink Bug, Oebalus Pugnax (F.), Damage And Monitoring Techniques In Rice, Oryza Sativa L., And Grain Sorghum, Sorghum Bicolor (L.), Aaron Joseph Cato

Graduate Theses and Dissertations

Rice stink bug, Oebalus pugnax (F.), is a serious pest of headed rice, Oryza sativa L. and an occasional pest of heading grain sorghum in the Mid-south. Work from this dissertation focuses on resolving gaps in and knowledge of rice stink bug sampling and management, and attempts to create a basis for rice stink bug damage assessment in future studies.

Field experiments were conducted from 2016-2018 to asses variation in sweep net sampling by observing producers, researchers, extension personnel, consultants and their workers. Large levels of variation were found in sweep lengths between observed sweepers and reliability of smaller sweep …

Epidemiology And Management Of Fusarium Head Blight And Foliar Fungal Diseases Of Wheat, Carlos Bolanos-Carriel

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

Fusarium head blight (FHB) caused by Fusarium graminearum, the FHB-associated mycotoxin deoxynivalenol (DON), and foliar fungal diseases are significant threats to wheat production. This research 1) evaluated the effects of fungicide chemical class, application timing, and cultivar resistance on FHB and DON under field conditions; 2) evaluated the effects of field-applied fungicide chemical class, grain moisture, and time on DON under grain storage conditions; 3) evaluated the effects of field-applied fungicide chemical class and time on trichothecene-related gene (Tri5) expression under grain storage conditions; 4) determined the optimum F. graminearum spore concentration and spike bagging period following …

Repeat Elements Organise 3d Genome Structure And Mediate Transcription In The Filamentous Fungus Epichloë Festucae, David J. Winter, Austen R. D. Ganley, Carolyn A. Young, Ivan Liachko, Christopher L. Schardl, Pierre-Yves Dupont, Daniel Berry, Arvina Ram, Barry Scott, Murray P. Cox

Plant Pathology Faculty Publications

Structural features of genomes, including the three-dimensional arrangement of DNA in the nucleus, are increasingly seen as key contributors to the regulation of gene expression. However, studies on how genome structure and nuclear organisation influence transcription have so far been limited to a handful of model species. This narrow focus limits our ability to draw general conclusions about the ways in which three-dimensional structures are encoded, and to integrate information from three-dimensional data to address a broader gamut of biological questions. Here, we generate a complete and gapless genome sequence for the filamentous fungus, Epichloë festucae. We use Hi-C …

Distribution And Incidence Of Mosaic And Evaluation Of Susceptibility In Louisiana's Current Sugarcane Germplasm, Jancee Rice

LSU Master's Theses

Mosaic is a viral disease of sugarcane caused primarily by Sorghum mosaic virus (SrMV) in Louisiana. Low mosaic incidence has resulted from successful breeding for resistance. However, mosaic was detected in breeding program experimental clones and a new cultivar, HoCP 09-804.Therefore, multiple research approaches were undertaken to assess the current status of mosaic in Louisiana sugarcane and prevent it from re-emerging as an important problem. Field surveys conducted during 2016-2018 of breeding program yield trials and experimental clone seed-cane increases determined disease incidence and distribution. Mosaic was detected in three of five sugarcane production areas and incidence ranged from 0 …