Neil Gudmestad - NDSU Publications

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Augmenting Fungicidal Activity of Tetraconazole with Chemosensitization Agents for Cercospora Leaf Spot Management
(North Dakota State University, 2017) Metz, Nicholas James
Cercospora beticola (Sacc.) is the causal agent of Cercospora leaf spot (CLS). CLS is considered to be one of the most destructive foliar diseases of sugar beet in the world. CLS is managed in part through resistant cultivars, crop rotation, and cultural practices, but timely fungicide applications are necessary to manage disease effectively. Heavy reliance on fungicides to manage CLS has led to the development of resistance to multiple classes of fungicides. The most widely used class of fungicides is the demethylation inhibitors (DMIs). DMI-resistant C. beticola isolates have been increasing in incidence over the past decade. Chemosensitization agents (CAs) are compounds that have little to no antifungal activity, but may increase efficacy of commercial fungicides when co-applied. CAs could lead to better management of CLS and reduced production costs.
An Automatic Weather Station Network For North Dakota
(North Dakota State University, 1990) Enz, John W.
Biology and Management of Fusarium Species on Sugar Beet
(North Dakota State University, 2017) Lai, Xiao
Minnesota and North Dakota together produce about 51% of the beet sugar in the United States of America. Fusarium diseases caused by Fusarium oxysporum f. sp. betae and F. secorum on sugar beet cause significant reduction in both root yield and sucrose concentration. This research was conducted to determine the best inoculation methods to induce Fusarium diseases on sugar beet seeds and plants and to evaluate fungicides for their efficacy at controlling Fusarium diseases in greenhouse conditions. The use of Fusarium colonized barley seeds in close proximity to sugar beet seeds and seedlings caused similar level of disease severity as the standard root-dipping method, and reduced the time for evaluation by directly inoculating seeds and 4-leaf stage plants rather than using older plants which have to be transplanted into new pots. Pydiflumetofen and metconazole fungicides used in-furrow have the potential to provide effective control of Fusarium diseases on sugar beet.
Blizzard Watch : Plant Sciences : 2017
(North Dakota State University, 2018) North Dakota State University. Department of Plant Sciences
Newsletter for the Department of Plant Sciences.
Characterization and Identification of Genetic Resistance to Puccinia Graminis F. Sp. Tritici in Triticum Aestivum and Hordeum Vulgare
(North Dakota State University, 2015) Zurn, Jason Daniel
Wheat stem rust, caused by Puccinia graminis f. sp. tritici (Pgt), is a major threat to wheat (Triticum aestivum) and barley (Hordeum vulgare) production. The emergence of the highly virulent Ug99-lineage stem rust races has stimulated research toward the identification and characterization of rust resistance genes in wheat and barley. Populations were developed to elucidate the inheritance and location of Pgt resistance genes in the common wheat landraces PI 626573 and PI 362698. The resistance present in PI 626573 was shown to be conferred by a single dominant gene (SrWLR) and was mapped to a 1.9 cM region on the long arm of chromosome 2B. This region is known to contain Sr9h which is effective against Ug99. SrWLR provides resistance to Pgt race RKQQC and Sr9h does not, suggesting SrWLR may be a new gene or allele of Sr9. Subsequent work has delimited the SrWLR region to 0.36 cM using a synteny-based approach. QTL analysis of the PI 362698 population using Pgt races identified significant (P < 0.1) resistance QTLs on multiple chromosomes. QTLs identified on chromosome 3B map to a similar location as Sr12 which does not provide resistance to Ug99-lineage races, suggesting a new allele or novel resistance gene. The QTLs identified on chromosomes 2B and 6A are thought to be Sr16 or an allele of Sr28 and Sr8a. Sr57 is known to be present in PI 362698 and is thought to be associated with Pgt QTLs detected on chromosome 7D. QTLs on chromosomes 5A and 5B are in regions where Pgt resistance genes have not been previously identified. Relative qPCR, fluorescence microscopy, and infection type approaches were utilized to phenotype barley for seedling resistance to Pgt race MCCFC at multiple time points. Statistical differences (P < 0.05) were found between accessions at 24 hours post inoculation using qPCR and displayed similar hierarchical ordering to microscopy observations. At early stages, the susceptible cultivar Steptoe had less fungal DNA than barley accessions containing resistance genes suggesting potential pre-haustorial resistance contributions. Temporal variation in resistance ranking suggests the qPCR assay may be valuable for dissecting pre- and post-haustorial resistance mechanisms.
Characterization of Cytochrome B from European Field Isolates of Cercospora Beticola with Quinone Outside Inhibitor Resistance
(North Dakota State University, 2012) Birla, Keshav
Cercospora leaf spot (CLS), caused by the fungal pathogen Cercospora beticola, is the most important foliar disease of sugar beet worldwide. Control strategies for CLS rely heavily on fungicides including quinone outside inhibitor (QOI) fungicides. We collected 866 C. beticola isolates from sugar beet growing regions in France and Italy and assessed their sensitivity to the QOI fungicide pyraclostrobin. To gain an understanding of the molecular basis of QOI resistance, we cloned the full-length coding region of Cbcytb. All tested QOI-resistant isolates harbored a point mutation in Cbcytb at nucleotide position 428 that conferred an exchange from glycine to alanine at amino acid position 143 (G143A). A PCR assay was developed to discriminate QOI-sensitive and QOI-resistant isolates based on the G143A mutation. Our results indicate that QOI resistance has developed in some European C. beticola populations in Italy and monitoring the G143A mutation is an essential fungicide resistance management strategy.
Characterization of Sensitivity of Sclerotinia Sclerotiorum Isolates from North Central U.S. to Thiophanate-Methyl and Metconazole
(North Dakota State University, 2013) Ameen, Gazala
Sclerotinia sclerotiorum (Lib.) de Bary causes Sclerotinia stem rot on canola and many other crops of economic importance in the U.S. SSR is primarily controlled with fungicides applied at flowering time. Most fungicides currently used to control SSR can promote resistance buildup in their target populations making monitoring of sensitivity important. In this study the reaction of S. sclerotiorum to thiophanate-methyl (TM) and metconazole (MTZ) was characterized. Samples collected in several states of north central U.S. were used. Three and ten isolates were considered to be moderately insensitive to TM and MTZ, respectively. Greenhouse trials indicated, however, that diseases caused by these isolates could be effectively controlled using currently recommended doses of each compound. In vitro sensitivity to TM was temperature dependent. A previously unreported mutation at codon E111D in the β-tubulin gene of a TM-moderately insensitive isolate was identified.
Cover Page
(1993)
Cover Page and Table of Contents
(1988)
Cover, table of contents and Index
(1978)
Development of Management Tools for Sunflower Downy Mildew (Plasmopara Halstedii) and Rust (Puccinia Helianthi)
(North Dakota State University, 2016) Humann, Ryan
Downy mildew (Plasmopara halstedii) and rust (Puccinia helianthi) are two economically important diseases of sunflower (Helianthus annuus) in North Dakota. Both diseases are capable of causing significant reductions in yield and quality. Effective disease management tools for both diseases are limited. Genetic resistance to both pathogens is frequently overcome by new pathogen races and only one efficacious fungicide is currently available to manage downy mildew. In order to identify additional management tools for downy mildew and rust, three research studies were done. The objective of the first study was to evaluate the efficacy of a novel fungicide, oxathiapiprolin, for the management of sunflower downy mildew. Seventeen inoculated field trials were conducted from 2011-2015 to test the efficacy of oxathiapiprolin. Results indicate that oxathiapiprolin significantly and consistently reduced downy mildew incidence and determined the optimal effective rate, which ranged from 9.37 – 18.75 µg active ingredient per seed. The second and third objectives focused on identifying accessions with novel sources of genetic resistance to P. halstedii and P. helianthi isolates collected in North Dakota. In the past, a disproportionate amount of resistance genes have been identified in wild Helianthus germplasm originating from Texas. For both studies, 182 wild H. annuus and 33 wild H. argophyllus accessions originating from Texas were obtained from the USDA North Central Regional Plant Introduction Station and screened to both pathogens in a greenhouse environment. Results from these individual studies identified numerous accessions with high levels of resistance to P. halstedii and P. helianthi, some accessions had high levels of resistance to both. Overall, results from these three studies will provide information and tools that will be useful for the long-term management of both diseases.
Downy Mildew of Sunflowers: Establishment of Baseline Sensitivity to Azoxystrobin and Monitoring for the Development of Fungicide Resistance and Plasmopara Halstedii Virulence Phenotype Changes
(North Dakota State University, 2017) Gilley, Michelle A.
Downy mildew, caused by Plasmopara halstedii (Farl.) Berl. and de Toni, is an economically important disease in cultivated sunflowers, Helianthus annuus L. The objectives of this study were to determine disease pressure in North Dakota and South Dakota, determine the virulence phenotypes in the pathogen population, determine the baseline sensitivity to azoxystrobin and evaluate select isolates for fungicide insensitivity. While downy mildew was present in many fields, incidence was typically low. To determine virulence phenotypes, selected isolates were evaluated on an expanded set of differential lines. New virulence was found to the Pl8 resistance gene, but no virulence was observed on the PlArg, Pl15, Pl17 and Pl18 genes. Using a discriminatory dose of 10 ug ai azoxystrobin/seed, no isolate approached infection levels found in inoculated, nontreated controls; therefore, the pathogen is considered sensitive to azoxystrobin in the greenhouse and azoxystrobin should still suppress downy mildew in the field.
Expanding Research Horizons
(1988) Wilkinson, T. Ross
Genetic and Molecular Characterization of Host Resistance and Susceptibility to Pyrenophora Teres F. Teres in Hordeum vulgare
(North Dakota State University, 2016) Richards, Jonathan
Pyrenophora teres f. teres, a necrotrophic fungal pathogen and causal agent of net form net blotch (NFNB), is an economically important pathogen of barley (Hordeum vulgare) and has potential to cause significant yield losses in barley production regions of the world. Host resistance is the most desirable means of disease management, yet the genetic nature of this pathosystem is exceedingly complex. With the goal of identifying novel sources of resistance to NFNB, a diverse population of barley accessions was utilized to conduct a genome wide association study which identified a total of 78 significant markers associated with disease reaction to three North American P. teres f. teres isolates, corresponding to 16 genomic loci. Five novel loci were detected and will be of importance for barley breeders for the improvement of elite barley lines. Dominant susceptibility harbored by barley cultivars Rika and Kombar to P. teres f. teres isolates 6A and 15A, respectively, were previously identified to exist in repulsion and mapped at low-resolution. Using 2976 recombinant gametes derived from a cross of Rika x Kombar and markers developed through mining of syntenous genes in Brachypodium distachyon, we mapped the Spt1 locus to ~0.24 cM near the centromere of chromosome 6H. Within the delimited Spt1 region, a receptor-like protein was identified as the primary candidate Spt1 gene designated Spt1.cg. Allele analysis of diverse barley lines exhibited a strong correlation with the presence of a Rika, Kombar, or Morex allele of Spt1.cg and susceptibility to P. teres f. teres isolates 6A, 15A, or Tra-A5/Tra-D10, respectively. Alleles of Spt1.cg appear highly diverged, stemming from selection pressures in wild barley populations and may be targeted by several unique necrotrophic effectors. The barley cultivar Morex rpr2 mutant, previously characterized to have lost Rpg1-mediated resistance to Puccinia graminis f. sp. tritici, also has compromised resistance to P. teres f. teres. Exome capture revealed a 12 base-pair deletion in a gene containing fibronectin and plant homeodomain domains with homology to Arabidopsis VIN3-like proteins. This gene may function in the perception of pathogen effector proteins, that disrupt cell wall integrity, eliciting early damage associated molecular pattern immunity responses.
Glycoalkaloid Profiling of Potato Genotypes from the North Dakota State University Potato Breeding Program
(North Dakota State University, 2013) Roman Martinez, Irene
Gylcoalkaloids (GA) are plant secondary metabolites that offer pests and disease resistance. Studies show correlation between GA content and CPB resistance. In this study, CPB resistance was assessed in a field trial at Grand Forks, ND, during 2012 for twenty-four genotypes from the NDSU Potato Breeding Program. Two treatments were applied, a block treated with imidacloprid (Admire®), and an untreated block. The treated block showed decreased CPB damage. Presence of aglycons (non-sugar moiety of GAs) was assessed by gas chromatography in foliar and tuber tissue. Distribution of GAs in the tuber was assessed to determine variation in tuber sections and whole tuber. Potato genotypes should be developed with tuber GAs levels below 20 mg/100 g fresh weight (FW) to ensure safety for human consumption. Focus should be on GAs that are only synthesized in the tuber, which will provide pests and disease resistance, while maintaining adequate yields and decreased inputs.
Identification and Genomic Analysis of Stagonospora Nodorum Blotch Susceptibility Genes in Wheat
(North Dakota State University, 2014) Shi, Gongjun
Parastagonospora nodorum is a necrotrophic fungal pathogen that causes the disease Stagonospora nodorum blotch (SNB) on wheat. The fungus produces necrotrophic effectors (NEs), that when recognized by corresponding host genes, cause cell death leading to disease. A novel NE, designated SnTox7, was identified from culture filtrates of isolate Sn6 of P. nodorum. SnTox7 is a small protein with estimated size less than 30 kDa. The interaction between SnTox7 and its corresponding host sensitivity gene, Snn7, explained 33% of the disease variation among a segregating F2 population. The Snn7 gene governs sensitivity to SnTox7 and was delineated to a 2.7 cM interval on the long arm of wheat chromosome 2D. Another host sensitivity gene Snn3- B1, conferring sensitivity to SnTox3, was previously mapped on the short arm of wheat chromosome 5B. Forty-four molecular markers were added to the genetic map to saturate the Snn3-B1 gene region. High-resolution mapping of the Snn3-B1 locus in 5,600 gametes delineated the gene to a 1.5 cM interval. The closely linked markers should be very useful for marker-assisted selection against Snn3-B1. A third host gene, Snn1, confers sensitivity to the NE Tox1. Snn1 was isolated through map-based cloning, and its structure, expression and allelic diversity were further characterized. A bacterial artificial chromosome (BAC) contig of about 2.5 Mb in size was identified to span the Snn1 locus through screening of Chinese Spring chromosome arm 1BS minimum tiling path (MTP) pools. Additional markers developed from BAC end sequences (BESs) delineated the Snn1 gene to a physical segment consisting of four BAC clones. Sequencing and bioinformatic analysis of these clones led to the identification of seven candidate genes. Six of the seven candidates were excluded through critical recombinants. The seventh gene, a cell wall-associated kinase (WAK), was verified as Snn1 through comparative sequence analysis with ethylmethane sulfonate (EMS)-induced mutants. The Snn1 transcription profile showed that it was regulated by light and possibly circadian rhythms. These results demonstrate that P. nodorum can hijack multiple host pathways driven by different classes of genes that typically confer resistance to biotrophic pathogens, thus demonstrating the surprisingly intricate nature of plant-necrotrophic pathogen interactions.
Inoculation Techniques, Development of Brassica Napus Breeding Lines and Identification of Markers Associated with Resistance to Sclerotinia Sclerotiorum (Lib.) De Bary
(North Dakota State University, 2012) Burlakoti, Pragyan
Sclerotinia stem rot caused by Sclerotinia sclerotiorum (Lib.) de Bary is an economic disease affecting canola (Brassica napus L). Since expression of sclerotinia stem rot symptoms shows much variability and the trait is quantitative in nature, reliable phenotypic evaluation methods for characterization are needed. The three major objectives of this dissertation were to: i) evaluate eight different inoculation methods to discriminate between S. sclerotiorum-resistant and susceptible B. napus germplasm; ii) develop breeding lines with resistance to multiple diseases, and; iii) to identify QTL associated with resistance to sclerotinia stem rot using association mapping (AM). The eight methods evaluated were the detached leaves, detached stems, petiole inoculation (PIT), straw-inoculation, stem-piercing with toothpick, mycelial spray (MSI), petal inoculation and oxalic acid assay. MSI and PIT can better discriminate between the isolates and germplasm. Breeding lines resistance to S. sclerotiorum, Leptosphaeria maculans, and Rhizoctonia solani were developed from a cross between two moderately sclerotinia stem rot resistant plant introductions (PI). F2 seedlings were screened for sclerotinia stem rot using PIT. Surviving plants were self pollinated and their progeny screened again. This process was repeated until the F6 generation. In addition, F5 seedlings were evaluated for their reaction to R. solani and F5 and F6 seedlings for their reaction to L. maculans. Eight lines were identified as moderately resistance to these three pathogens. The genomes of a group of 278 B. napus plant introductions were screened using Diversity Array Technology to detect QTL associated with resistance to sclerotinia stem rot. The population was classified into nine sub-populations and 32 significant markers each explaining between 1.5 and 4.6% of the variation were identified. Blastn search indicates that similar nucleotide sequences are distributed throughout the genomes of B. oleracea, B. rapa, and A. thaliana. Results of these studies suggest the PIT and MSI are reliable screening tools to evaluate materials for resistance to sclerotinia stem rot; materials identified as resistant to S. sclerotiorum were also moderately resistant against R. solani and L. maculans and could be valuable sources for canola improvement programs; and AM allowed us to identify QTL associated with resistance to sclerotinia stem rot.
It's Happening at State: April 12, 2006
(North Dakota State University, 2006-04-12)
Provides summary information of news and events of interest to the faculty and staff of NDSU.
It's Happening at State: August 26, 2009
(North Dakota State University, 2009-08-26)
Provides summary information of news and events of interest to the faculty and staff of NDSU.
It's Happening at State: August 29, 2001
(North Dakota State University, 2001-08-29)
Provides summary information of news and events of interest to the faculty and staff of NDSU.

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