Plant Pathology Commons^™

Integrating Genomic And Phenomic Breeding Tools For Wheat Stem Sawfly Resistance In Hard Winter Wheat, Sydney E. Graham

Dissertations and Doctoral Documents, University of Nebraska-Lincoln, 2023–

The wheat stem sawfly (WSS; Cephus cinctus) is an insect pest that affects wheat (Triticum aestivum) in the Northern Great Plains. This pest causes stem cutting that makes the plants susceptible to lodging and results in up to 30% yield loss. The primary management strategy for producers is utilizing host plant resistance, for which the main trait is stem solidness. This trait increases the pith thickness and provides resistance to the WSS by increasing larval mortality and reducing stem cutting. While stem solidness is largely controlled by a known major gene (SSt1), the phenotypic expression is also …

Morphological, Molecular, And Morphometric Analysis Of Aphelenchoides Besseyi On Organic Rice (Oryza Sativa) Seeds In The Beringin District, Deli Serdang Regency, Indonesia, Suswati Suswati, Azwana Azwana, Ifan Aulia Candra, Fitrianingrum Kuniawati, Khofifah Muhaimini Siregar, Asmaul Hasanah, Aldy Elvanandar Nasution

Makara Journal of Science

Aphelenchoides besseyi, a nematode, can infect rice resulting in the white shoot disease, which decreases the germina-tion rate and even causes seedling death. A. besseyi has recently been reported to mainly attack the organic rice varie-ties especially Pandanwangi and Ciherang in the Pasar Kawat, Beringin District, Deli Serdang, Indonesia. This research investigated A. besseyi via morphological, molecular, and morphometric approaches. The nematodes were observed in an area of 2000 m2, divided into five sample plots each with an area of 400 m2 on which Pandan Wangi and Ciherang rice were cultivated. Nematode morphology was observed using a stereo microscope at …

Clonal Variation In Effector Gene Expression As A Mechanism For Pathogenic Adaptation In Magnaporthe Oryzae, Rebekah J. Ellsworth

Theses and Dissertations--Plant Pathology

Magnaporthe oryzae is a filamentous fungal pathogen that causes destructive diseases in cereals, including rice blast, wheat blast, and gray leaf spot. It is responsible for 10–30% annual yield losses in rice (Nalley et al., 2016) and up to 100% loss in wheat under favorable conditions (Kohli et al., 2011). Disease management typically relies on the use of resistant cultivars, but M. oryzae rapidly overcomes host resistance by mutating or deleting avirulence (AVR) genes recognized by host immune receptors. This rapid adaptation, often occurring within one to two growing seasons, presents a major challenge to breeding for durable resistance.

The …

Role Of Chemotype In Aggressiveness, Toxicity, And Competitive-Ness Of Fusarium Graminearum On Wheat, Simran Goyal

Theses and Dissertations--Plant Pathology

Fusarium Head Blight (FHB) of wheat, caused by the fungus Fusarium graminearum, is a devastating disease that led to epidemics in the U.S. during the 1990s, resulting in economic losses exceeding $2.6 billion. Typical symptoms include bleached spikelets and shriveled grains, often contaminated with trichothecene mycotoxins that make them unsafe for food or feed. FHB severity and mycotoxin production are influenced by a complex interplay between host genotype, environmental factors, and pathogen genotype. Integrated management practices that include the use of more resistant cultivars, crop rotation, and fungicide applications help to reduce disease incidence and severity. Disease forecasting models …

Cytotoxic Potential Of Fungi In The Genus Ganoderma, Abril Chao, Omobolanle A. Ayangade, Braham Dhillon, Navi Gill

Mako: NSU Undergraduate Student Journal

Ganoderma lucidum is a mushroom forming fungus that has been used in traditional Chinese medicine for over 2,000 years. G. lucidum, also known as lingzhi or reishi, is consumed in several Asian cultures to promote health and longevity. Bioactive molecules with anticancer properties have been isolated and characterized primarily from the species Ganoderma lucidum, and the cytotoxic potential of other species in the genus Ganoderma remains relatively unclear. Bioactive molecules isolated from mushroom fruiting bodies are demonstrated to have cytotoxicity against different cancer cell lines. Triterpenes and polysaccharides are the two major groups of compounds that exhibit antitumor and anti-inflammatory …

The Plant Disease Triangle Facing Climate Change: A Molecular Perspective, Charles Roussin-Léveillée, Christina A. M. Rossi, Christian Castroverde, Peter Moffett

Biology Faculty Publications

No abstract provided.

Agrobacterium-Mediated Genetic Transformation And Plant Regeneration From Cotyledons In Philippine Eggplant (Solanum Melongena L.) Acc. ‘Ph 11424’, Mark Gabriel Sagarbarria, John Albert Caraan, Patrick Lipio, Ian Bien Oloc-Oloc, Kazuo Watanabe, Desiree Hautea

The Philippine Agricultural Scientist

Eggplant (Solanum melongena L.) is one of the most important vegetables grown and consumed in the Philippines hence, continuous breeding programs are vital to maintain the supply of this economically important crop. This study demonstrates the first successful Agrobacterium-mediated genetic transformation and plant regeneration of the Philippine eggplant cultivar ‘PH 11424’, also known as ‘Mistisa’. Cotyledons from 2-wk-old seedlings were used as explants, which were transformed with disarmed Agrobacterium tumefaciens strain LBA4404 harboring a binary vector for CRISPR/Cas9 expression and hygromycin phosphotransferase (HPT), an antibiotic selection marker. Growth of shoot primordia from the agro-infected explants was observed during selective culture …

Biology And Ecology Of Neonectria Magnoliae And Neonectria Punicea, Two Understudied Neonectria Species In West Virginia, Hannah Marie Petronek

Graduate Theses, Dissertations, and Problem Reports (ETD)

The family Nectriaceae includes numerous phytopathogenic fungi that cause canker diseases on both angiosperm and conifer hosts worldwide. Numerous Neonectria spp. cause cankers on hardwoods and conifers in North America, but their roles in contributing to tree decline and mortality outside of beech bark disease are largely understudied. One such pathogen, Neonectria magnoliae, causes perennial cankers on two native hosts in central Appalachia: Fraser magnolia (Magnolia fraseri) and tulip-poplar (Liriodendron tulipifera). We also recently confirmed N. magnoliae from non-native star magnolia (Magnolia stellata) in West Virginia. Both native hosts occur in the central …

Investigating Birds As Dispersal Vectors Of Litylenchus Crenatae Subsp. Mccannii (Anguinidae), The Nematode Associated With Beech Leaf Disease, Spencer Rock Parkinson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Beech leaf disease (BLD) is an emerging forest pathogen primarily affecting American beech (Fagus grandifolia, Ehrh.) in North America and has been attributed to tree mortality of sapling sized trees within five to seven years of infection. Symptoms typically occur in regenerating American beech thickets sprouting from roots of trees killed by beech bark disease. Scientists first observed BLD in Ohio in 2012 and currently has spread to 15 states in the USA and one Canadian province. The nematode Litylenchus crenatae subsp. mccannii (Lcm) is highly associated with BLD symptoms, interveinal chlorosis and defoliation of leaves, and is currently …

Identification And Characterization Of Geotrichum Candidum Isolates From Peach With Reduced Sensitivity To Propiconazole, Sara Price

All Theses

Geotrichum candidum Link (1809) is a yeast-like fungus that causes sour rot of stone fruits, including peach (Prunus persica). The disease caused damage between 2021 and 2023 to the peach crop kept in cold storage at a commercial farm in South Carolina despite preharvest and postharvest applications of fungicides. Isolates from 41 symptomatic fruit, from a South Carolina (SC) commercial packing house, as well as other isolates obtained from South Carolina were identified to be G. candidum based on species-specific PCR amplifications of the β tubulin gene. Commonly used postharvest fungicide fludioxonil had no effect on G. candidum mycelial growth …

Gene Expression Changes Linked To Phenylpropanoid-Based Resistance To Fusarium Head Blight Of Wheat, Shiv Singla

Department of Plant Pathology: Dissertations, Theses, and Student Research

Fusarium graminearum is a devastating pathogen of wheat that causes Fusarium head blight (FHB) and contaminates the grain with the mycotoxin deoxynivalenol (DON). Resistance to FHB is quantitative and it is important to identify additional genes conferring resistance against it. The goal of this thesis was to examine if the constitutive expression of two sorghum phenylpropanoid pathway genes, SbCCoAOMT (encoding caffeoyl-CoA O-methyltransferase) and SbC3’H (encoding p-coumarate 3-hydroxylase), in the moderately-susceptible spring wheat CB037 can provide Type-I and Type-II resistance to F. graminearum and determine the underlying mechanisms of the enhanced resistance. The constitutive expression lines (CCoAOMT413, CCoAOMT421, C3H112, …

Identification Of Quantitative Trait Loci (Qtls) For Resistance To Bacterial Leaf Streak: Xanthomonas Translucens Using Qtl And Association Mapping In Three Populations Of Soft Red Winter Wheat, Benjamin Tyler Meritt

LSU Doctoral Dissertations

Bacterial leaf streak (BLS) and black chaff, caused by Xanthomonas translucens pv. undulosa (Xtu), can be a very destructive disease of wheat, especially in the warmer, wetter areas of the Southeastern U.S. Yield losses of up to 40 percent have been recorded in some cases in southern wheat growing regions. With no effective agronomic or chemical method of disease control, identification of genetic resistance is seen as a promising solution. Three soft red winter wheat populations (GAWN, ARK-SNP, and AGS 2060- AGS 2035 DH) representative of soft red winter wheat germplasm in the southeastern U.S. developed by …

Increasing The Resilience Of Plant Immunity To A Warming Climate, Jong Hum Kim, Christian Castroverde, Shuai Huang, Chao Li, Richard Hilleary, Adam Seroka, Reza Sohrabi, Diana Medina-Yerena, Bethany Huot, Jie Wang, Sharon Marr, Mary Wildermuth, Tao Chen, John Macmicking, Sheng Yang He

Biology Faculty Publications

Extreme weather conditions associated with climate change affect many aspects of plant and animal life, including the response to infectious diseases. Production of salicylic acid (SA), a central plant defence hormone, is particularly vulnerable to suppression by short periods of hot weather above the normal plant growth temperature range via an unknown mechanism. Here we show that suppression of SA production in Arabidopsis thaliana at 28 °C is independent of PHYTOCHROME B (phyB) and EARLY FLOWERING 3 (ELF3), which regulate thermo-responsive plant growth and development. Instead, we found that formation of GUANYLATE BINDING PROTEIN-LIKE 3 (GBPL3) defence-activated biomolecular condensates (GDACs) …

Epistatic Interaction Between Rhg1‑A And Rhg2 In Pi 90763 Confers Resistance To Virulent Soybean Cyst Nematode Populations, Pawan Basnet, Clinton G. Meinhardt, Mariola Usovsky, Jason D. Gillman, Trupti Joshi, Qijian Song, Brian Diers, Melissa G. Mitchum, Andrew M. Scaboo

Biomedical Sciences

Key message

An epistatic interaction between SCN resistance loci rhg1-a and rhg2 in PI 90763 imparts resistance against virulent SCN populations which can be employed to diversify SCN resistance in soybean cultivars.

Abstract

With more than 95% of the $46.1B soybean market dominated by a single type of genetic resistance, breeding for soybean cyst nematode (SCN)-resistant soybean that can effectively combat the widespread increase in virulent SCN populations presents a significant challenge. Rhg genes (for Resistance to Heterodera glycines) play a key role in resistance to SCN; however, their deployment beyond the use of the rhg1-b allele has been …

Functional Characterization Of A Putative Alternative Oxidase In Sporisorium Reilianum F. Sp. Zeae., Emma A Lamb

College of Arts & Sciences Senior Theses

Sporisorium reilianum is a pathogenic basidiomycete fungus with two formae speciales, each capable of infecting corn (SRZ) or sorghum (SRS), respectively. This fungus is also a dimorphic variety, meaning it can switch between its haploid, yeast-like sporidia and diploid teliospore stages over the course of its life cycle (Schirawski). When S. reilianum is found in a haploid state and conditions are favorable, it will mate with a compatible non-self mating type to begin filamentous growth and proliferation in the plant host (Zhao). S. relianum, like most fungi, utilizes the four classical components of the electron transport chain to produce …

Salicylic Acid And N-Hydroxypipecolic Acid At The Fulcrum Of The Plant Immunity-Growth Equilibrium, Alyssa Shields, Vanessa Shivnauth, Christian Danve M. Castroverde

Biology Faculty Publications

Salicylic acid (SA) and N-hydroxypipecolic acid (NHP) are two central plant immune signals involved in both resistance at local sites of pathogen infection (basal resistance) and at distal uninfected sites after primary infection (systemic acquired resistance). Major discoveries and advances have led to deeper understanding of their biosynthesis and signaling during plant defense responses. In addition to their well-defined roles in immunity, recent research is emerging on their direct mechanistic impacts on plant growth and development. In this review, we will first provide an overview of how SA and NHP regulate local and systemic immune responses in plants. We …

The Role Of Nitric Oxide In Inter- And Intra- Cellular Signaling In Plant Defense, Fan Xia

Theses and Dissertations--Plant Pathology

Plants have evolved a sophisticated immune system to defend themselves against pathogens. This immune response can be triggered in response to pathogen-associated molecular patterns (PAMP) or specialized effectors that are recognized by the plant resistance (R) proteins. The latter, commonly referred to as effector-triggered immunity (ETI), is well known to induce broad-spectrum resistance throughout the plants. This phenomenon known as systemic acquired resistance (SAR) is regulated by several chemical signals including salicylic acid (SA), and free radical nitric oxide (NO) and reactive oxygen species (ROS). These signals operate in two parallel branches with NO/ROS functioning downstream of pipecolic acid (Pip) …

Epinasty Accompanies Potassium Nitrate-Induced Flower Bud Break In 'Carabao' Mango [Research Note], Ulysses Besas, Calixto Protacio

The Philippine Agricultural Scientist

The hypothesis that potassium nitrate application promotes epinasty in ‘Carabao’ mango through increased ethylene production was investigated. The degree of drooping, apical primordium growth as affected by shoot ethylene and levels after potassium nitrate spraying were monitored. Evidence presented established for the first time in ‘Carabao’ mango that epinasty occurred just before flower emergence, coinciding with visible bud break, and extended up to 18 days, marking floral anthesis. The possible reasons could be the higher levels of ethylene at 0.31% and earlier increase of ethylene in the shoot apex at four hours and apical primordium growth. Increased ethylene levels at …

Efficacy Study Of Selected Maize (Zea Mays L.) Genotypes Against The Asian Corn Borer, Ostrinia Furnacalis (Guenée), Yoryncita Marfori, Merdelyn Caasi-Lit, Tonette Laude

The Philippine Agricultural Scientist

Laboratory and screen house studies were conducted to assess the efficacy of selected twenty-six maize varieties against Asian corn borer (ACB), Ostrinia furnacalis (Guenée). Hierarchical tree based on resistance parameters clearly revealed that the twenty-six maize varieties are best classified into three groups, viz. resistant, intermediate, and susceptible. In laboratory test, the varieties RCS2, RCS4, RCS5, 'IPB Var13', Bt2, Bt3, and Bt4 were consistently identified as highly resistant. Further examinations in stalk feeding assay showed that the resistant varieties had sharp decline in larval survival (LS) on the 2^nd to the 5^th day of larval feeding in …

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, …

Genetic Relationships In The Toxin-Producing Fungal Endophyte, Alternaria Oxytropis Using Polyketide Synthase And Non-Ribosomal Peptide Synthase Genes, Rebecca Creamer, Deana Baucom Hille, Marwa Neyaz, Tesneem Nusayr, Christopher L. Schardl, Daniel Cook

Plant Pathology Faculty Publications

The legume Oxytropis sericea hosts a fungal endophyte, Alternaria oxytropis, which produces secondary metabolites (SM), including the toxin swainsonine. Polyketide synthase (PKS) and non-ribosomal peptide synthase (NRPS) enzymes are associated with biosynthesis of fungal SM. To better understand the origins of the SM, an unannotated genome of A. oxytropis was assessed for protein sequences similar to known PKS and NRPS enzymes of fungi. Contigs exhibiting identity with known genes were analyzed at nucleotide and protein levels using available databases. Software were used to identify PKS and NRPS domains and predict identity and function. Confirmation of sequence for selected gene …

Genetic Variability In Fusarium Oxysporum F. Sp. Vasinfectum Causing Damping-Off Of Cotton (Gossypium Barbadense L.) Seedlings [Research Note], Reda Helmy Sammour, Salah Abdel Moemen, Eman Elagamy

The Philippine Agricultural Scientist

The genetic variability of Fusarium oxysporum f. sp. vasinfectum isolates from Gossypium barbadense L. seedlings were assessed using pathogenicity, mycelial compatibility, and RAPD analyses. The results showed that the disease incidence percentages and compatibility percentages considerably varied, extending from 33.2 to 86.6 % and 6 to 60 %, respectively in North Egypt and from 33.3 to 66.6 % and 0.0 to 20% in South Egypt. It also showed that the isolates ISO-8 and ISO-19 had the lowest disease incidence (33.2%) as compared with isolate ISO-5 (86.6%). Results of the mycelial compatibility had a reversible relationship with disease incidence percentage. Cluster …

Temperature Regulation Of Plant Hormone Signaling During Stress And Development, Christian Castroverde, Damaris Dina

Biology Faculty Publications

Global climate change has broad-ranging impacts on the natural environment and human civilization. Increasing average temperatures along with more frequent heat waves collectively have negative effects on cultivated crops in agricultural sectors and wild species in natural ecosystems. These aberrantly hot temperatures, together with cold stress, represent major abiotic stresses to plants. Molecular and physiological responses to high and low temperatures are intricately linked to the regulation of important plant hormones. In this review, we shall highlight our current understanding of how changing temperatures regulate plant hormone pathways during immunity, stress responses and development. This article will present an overview …

Analysis Of Symptom Expressions And Transmission Rates Caused By The Plant Pathogen Phytophthora Ramorum On Native Chaparral Plants From The Genus Arctostaphylos, Bharati Gaonker

Natural Sciences and Mathematics | Biological Sciences Master's Theses

Phytophthora ramorum is the causal agent of Sudden Oak death (SOD), ramorum dieback and ramorum leaf blight which affect both forest environments and nurseries. This oomycete pathogen has had a huge economic impact on the nursery and lumber industry. Forests in California have experienced substantial mortality of oaks affecting the forest dynamics and diversity. Our research investigates four native species and two ornamental cultivars of plants, which belong to the genus Arctostaphylos (manzanita) and are considered to be new hosts for P. ramorum in the chaparral ecosystem of California. Symptom expression and transmission rates were analyzed on Arctostaphylos glauca, …

Identification And Comparison Of Arbuscular Mycorrhizal Fungi And Soil Microbiomes Between American Chestnuts And Surrounding Hardwoods, Sarah Andrews, Geoffrey Eger, Isabella Vahle

Symposium of Student Scholars

Background/Questions/Methods

The introduction of the Chinese chestnut blight in 1904 decimated native American chestnut (Castanea dentata (Marshall) Borkh.) populations. In this study we aim to: 1) document the location of individual chestnuts in our vicinity; 2) document healthy versus blight infected individuals; 3) characterize putative differences in the soil microbiome between infected and non-infected individuals, as well as between chestnuts and hardwood neighbors. With this information we hope to provide new insights into mechanisms that may enhance blight and fungal resistance in American chestnuts through the understanding of the interactions between the trees and their surrounding soil microbiome.

Soil …

Inhibition Of Biofilm Formation By The Synergistic Action Of Egcg-S And Antibiotics, Shrameeta Shinde, Lee Lee, Tinchun Chu

Department of Biology Faculty Scholarship and Creative Works

Biofilm, a stress-induced physiological state, is an established means of antimicrobial tolerance. A perpetual increase in multidrug resistant (MDR) infections associated with high mortality and morbidity have been observed in healthcare settings. Multiple studies have indicated that the use of natural products can prevent bacterial growth. Recent studies in the field have identified that epigallocatechin gallate (EGCG), a green tea polyphenol, could disrupt bacterial biofilms. A modified lipid-soluble EGCG, epigallocatechin-3-gallate-stearate (EGCG-S), has enhanced the beneficial properties of green tea. This study focuses on utilizing EGCG-S as a novel synergistic agent with antibiotics to prevent or control biofilm. Different formulations of …

Polerovirus Genomic Variation And Mechanisms Of Silencing Suppression By P0 Protein, Natalie M. Holste

School of Biological Sciences: Dissertations, Theses, and Student Research

The family Luteoviridae consists of three genera: Luteovirus, Enamovirus, and Polerovirus. The genus Polerovirus contains 32 virus species. All are transmitted by aphids and can infect a wide variety of crops from cereals and wheat to cucurbits and peppers. However, little is known about how this wide range of hosts and vectors developed. In poleroviruses, aphid transmission and virion formation is mediated by the coat protein read-through domain (CPRT) while silencing suppression and phloem limitation is mediated by Protein 0 (P0)—a protein unique to poleroviruses. P0 gives poleroviruses a great advantage amongst plant viruses and diversifies polerovirus species, but the …

Subcellular Localization Of Tobacco Sabp2 Under Normal And Stress Conditions, Sanjeev Das

Undergraduate Honors Theses

Subcellular Localization of Tobacco SABP2 under Normal and Stress Conditions

Salicylic acid (SA), a phytohormone, plays an important role in plant physiology. SA mediated innate immune pathway is an important pathway for plant immunity against pathogens. Plants resisting pathogen infection synthesize higher levels of Methyl Salicylate (MeSA), which is then converted to SA by the esterase activity of Salicylic Acid Binding Protein 2 (SABP2). The high level of the converted SA leads to enhanced pathogen resistance. The study of subcellular localization of a protein is critical in explaining its potential biochemical functions. SABP2 tagged with eGFP was expressed transiently in …

Smrt Sequencing Of Paramecium Bursaria Chlorella Virus-1 Reveals Diverse Methylation Stability In Adenines Targeted By Restriction Modification Systems, Samantha R. Coy, Eric R. Gann, Spiridon E. Papoulis, Michael E. Holder, Nadim J. Ajami, Joseph F. Petrosino, Erik R. Zinser, James L. Van Etten, Steven W. Wilhelm

James Van Etten Publications

Chloroviruses (family Phycodnaviridae) infect eukaryotic, freshwater, unicellular green algae. A unique feature of these viruses is an abundance of DNA methyltransferases, with isolates dedicating up to 4.5% of their protein coding potential to these genes. This diversity highlights just one of the long-standing values of the chlorovirus model system; where group-wide epigenomic characterization might begin to elucidate the function(s) of DNA methylation in large dsDNA viruses. We characterized DNA modifications in the prototype chlorovirus, PBCV-1, using single-molecule real time (SMRT) sequencing (aka PacBio). Results were compared to total available sites predicted in silico based on DNA sequence alone. SMRT-software detected …

A Transcriptional Regulatory Network Of Rsv3-Mediated Extreme Resistance Against Soybean Mosaic Virus, Lindsay C. Demers, Neelam R. Redekar, Aardra Kachroo, Sue A. Tolin, Song Li, M. A. Saghai Maroof

Plant Pathology Faculty Publications

Resistance genes are an effective means for disease control in plants. They predominantly function by inducing a hypersensitive reaction, which results in localized cell death restricting pathogen spread. Some resistance genes elicit an atypical response, termed extreme resistance, where resistance is not associated with a hypersensitive reaction and its standard defense responses. Unlike hypersensitive reaction, the molecular regulatory mechanism(s) underlying extreme resistance is largely unexplored. One of the few known, naturally occurring, instances of extreme resistance is resistance derived from the soybean Rsv3 gene, which confers resistance against the most virulent Soybean mosaic virus strains. To discern the regulatory mechanism …