Plant Pathology Commons^™

Cdc5, A Dna Binding Protein, Positively Regulates Posttranscriptional Processing And/Or Transcription Of Primary Microrna Transcripts, Shuxin Zhang, Meng Xie, Guodong Ren, Bin Yu

Center for Plant Science Innovation: Faculty Publications

CDC5 is a MYB-related protein that exists in plants, animals, and fungi. In Arabidopsis, CDC5 regulates both growth and immunity through unknown mechanisms. Here, we show that CDC5 from Arabidopsis positively regulates the accumulation of microRNAs (miRNAs), which control many biological processes including development and adaptations to environments in plants. CDC5 interacts with both the promoters of genes encoding miRNAs (MIR) and the DNA-dependent RNA polymerase II. As a consequence, lack of CDC5 reduces the occupancy of polymerase II at MIR promoters, as well as MIR promoter activities. In addition, CDC5 is associated with the DICER–LIKE1 complex, …

Characterization And Investigation Of At2g42005 In Arabidopsis Thaliana, A Nematode-Induced Transporter, Rachel Medina

Undergraduate Review

Meloidogyne incognita is an obligate parasitic roundworm that infects the root tips of a wide variety of host plants. This infection directly affects the crop production globally with the loss of crops such as tomatoes, carrots, and potatoes. Nematode infection manipulates the plant root by altering gene expression for nematode benefit. Genes such as At2g42005, a putative amino acid transporter, have been found to be upregulated by nematode infection. Characterizing the role of the At2g42005 gene in Arabidopsis thaliana is the first step to understanding its function in nematode infection. The role of At2g42005 were explored by creation of a …

Comparative Studies Of Differential Gene Calling Using Rna-Seq Data, Ximeng Zheng, Etsuko N. Moriyama

Center for Plant Science Innovation: Faculty Publications

Background: With its massive amount of data, gene-expression profiling by RNA-Seq has many advantanges compared with microarray experiments. RNA-Seq analysis, however, is fundamentally different from microarray data analysis. Techniques developed for analyzing microarray data thus cannot be directly applicable for the digital gene expression data. Several statistical methods have been developed for identifying differentially expressed genes specifically from RNA-Seq data over the past few years.
Results: In this study, we examined the performance of differential gene-calling methods using RNA-Seq data in practical situations. We focused on two representative methods: one parametric method, DESeq, and one nonparametric method, NOISeq. …

A Novel Function Prediction Approach Using Protein Overlap Networks, Shide Liang, Dandan Zheng, Daron M. Standley, Huarong Guo, Chi Zhang

Center for Plant Science Innovation: Faculty Publications

Background: Construction of a reliable network remains the bottleneck for network-based protein function prediction. We built an artificial network model called protein overlap network (PON) for the entire genome of yeast, fly, worm, and human, respectively. Each node of the network represents a protein, and two proteins are connected if they share a domain according to InterPro database.
Results: The function of a protein can be predicted by counting the occurrence frequency of GO (gene ontology) terms associated with domains of direct neighbors. The average success rate and coverage were 34.3% and 43.9%, respectively, for the test genomes, …

A Thraustochytrid Diacylglycerol Acyltransferase 2 With Broad Substrate Specificity Strongly Increases Oleic Acid Content In Engineered Arabidopsis Thaliana Seeds, Chunyu Zhang, Umidjon Iskandarov, Elliott T. Klotz, Robyn L. Stevens, Rebecca E. Cahoon, Tara J. Nazarenus, Suzette L. Pereira, Edgar B. Cahoon

Center for Plant Science Innovation: Faculty Publications

Diacylglycerol acyltransferase (DGAT) catalyses the last step in acyl-CoA-dependent triacylglycerol (TAG) biosynthesis and is an important determinant of cellular oil content and quality. In this study, a gene, designated TaDGAT2, encoding a type 2 DGAT (DGAT2)-related enzyme was identified from the oleaginous marine protist Thraustochytrium aureum. The deduced TaDGAT2 sequence contains a ~460 amino acid domain most closely related to DGAT2s from Dictyostelium sp. (45–50% identity). Recombinant TaDGAT2 restored TAG biosynthesis to the Saccharomyces cerevisiae H1246 TAG-deficient mutant, and microsomes from the complemented mutant displayed DGAT activity with C16 and C18 saturated and unsaturated fatty acyl-CoA and diacylglycerol …

Identification Of Sources Of Resistance To Damping-Off And Early Root/Hypocotyl Damage From Rhizoctonia Solani In Common Bean (Phaseolus Vulgaris L.), P. A. Peña, James R, Steadman, Kent M. Eskridge, Carlos A. Urrea

Panhandle Research and Extension Center

Rhizoctonia solani causes economically important root and hypocotyl diseases in common bean throughout the world. Root health is a vital factor in plant development and root diseases would negatively influence water and nutrient uptake as well as cause direct stand reduction and root rot damage to the crop. An efficient common bean screening method to evaluate damping-off and early root/ hypocotyl damage from R. solani was developed and used to identify dry bean lines with levels of resistance to this disease. Two sets of 163 and 111 lines previously evaluated for drought tolerance in Nebraska and Puerto Rico were evaluated …

Fuzzy Clustering Of Cpp Family In Plants With Evolution And Interaction Analyses, Tao Lu, Yongchao Dou, Chi Zhang

Center for Plant Science Innovation: Faculty Publications

Background: Transcription factors have been studied intensively because they play an important role in gene expression regulation. However, the transcription factors in the CPP family (cystein-rich polycomb-like protein), compared with other transcription factor families, have not received sufficient attention, despite their wide prevalence in a broad spectrum of species, from plants to animals. The total number of known CPP transcription factors in plants is 111 from 16 plants, but only 2 of them have been studied so far, namely TSO1 and CPP1 in Arabidopsis thaliana and soybean, respectively.
Methods: In this work, to study their functions, we applied …

Alternative Methods Of Control For Phytophthora Nicotianae Of Tobacco, Anna M. Holdcroft

Theses and Dissertations--Plant Pathology

Kentucky is the nation’s leading producer of burley tobacco and the crop’s most economically important disease is black shank, caused by Phytophthora nicotianae (Pn). Current management is effective, however, problems with expense and pathogen persistence are issues. Two alternative methods for control of Pn were examined: biofumigation and soil application of an organic, yeast fermentation‐derived product (Soil‐Set). Field studies in 2009 and 2010 found no effect on populations of fungi, disease severity of Pn, and yield between mustard‐ and wheat‐amended plots. Experiments in the greenhouse suggested that survival of Pn was impacted by biomass rather than biofumigation. Biofumigation is not …

Efficacy Of Foliar Fungicides And Application Timing Of Stratego Yld On Field Corn In Nebraska, 2013, C. M. Schleicher, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

A foliar fungicide efficacy timing trial was conducted at the University of Nebraska-Lincoln South Central Agricultural Laboratory near Clay Center, NE. Corn hybrid NK ‘N68B’, rating of “fair” (7 out of 9) for gray leaf spot (GLS), not rated for common rust (CR), and “excellent” (2 out of 9) for southern rust (SR), was planted on 15 May in 30-in. rows at a target population of 31,763 plants/A. The trial area was disked with corn as the previous year’s crop. Nine treatments and a nontreated control were replicated six times in a randomized complete block design. Each plot was four …

Evaluation Of Foliar Fungicide And Application Timing On Field Corn Following Hail Event At Scal In Nebraska, 2013, C. M. Schleicher, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

A foliar fungicide efficacy timing trial was conducted at the University of Nebraska-Lincoln South Central Agricultural Laboratory near Clay Center, NE to determine the potential effect of foliar fungicides and their application timing on lodging and yield after a late season hail event. Novartis corn hybrid N6800 GT with CruiserMaxx 250 seed treatment was planted on 24 May in 30 in. rows with a target population of 32,000 plants/A. Force 3G (4 oz/1,000 row ft) was applied in-furrow at planting. Lexar (3 qt/A) + Roundup UltraMax (32 fl oz/A) was applied on 5 Jun. The trial area had corn as …

Efficacy Evaluation Of Fortix And Headline Amp Application Timing In Field Corn In Nebraska, 2013, C. M. Schleicher, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

A foliar fungicide efficacy timing trial was conducted at the University of Nebraska-Lincoln South Central Agricultural Laboratory near Clay Center, NE. Corn hybrid NK ‘N68B’, rating of “fair” (7 out of 9) for gray leaf spot (GLS), not rated for common rust (CR), and “excellent” (2 out of 9) for southern rust (SR), was planted on 15 May in 30-in. rows at a target population of 31,763 plants/A. The trial area was disked with corn as the previous year’s crop. Nine treatments were replicated six times in a randomized complete block design. Each plot was four rows (10 ft) wide …

Efficacy Evaluation Of Foliar Fungicide Application Timing In Field Corn In Nebraska, 2012, C. M. Schleicher, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

A foliar fungicide efficacy trial was conducted at the University of Nebraska-Lincoln South Central Agricultural Laboratory near Clay Center, NE. DeKalb corn hybrid DKC 64-83, rating of “good” (6 out of 9) for gray leaf spot (GLS), “very good” (4 out of 9) for common rust (CR), and “good” (5 out of 9) for southern rust (SR), was planted on 26 Apr in 30-in. rows at a target population of 30,600 plants/A. The trial area was disked with corn as the previous year’s crop. Six foliar fungicide treatments and a non-treated control were replicated six times in a randomized complete …

What’S New In Plant Pathology, Loren Giesler, Tamra A. Jackson-Ziems, Casey Schleicher, Kevin Korus

Department of Plant Pathology: Faculty Publications

Extension Plant Pathology Team Update

Plant and Pest Diagnostic Clinic Update

Disease Management Products

Table 1. Foliar Fungicide Label Updates

Table 2. New Products

Impacts Of Drought On Disease Development And Management, Stephen Wegulo, Loren Giesler, Robert Harveson, Tamra A. Jackson-Ziems, Bo Liu, Kevin Korus

Department of Plant Pathology: Faculty Publications

Drought conditions such as those that occurred in Nebraska in 2012 can impact the development of plant diseases. In general drought slows down or prevents the development of plant diseases caused by pathogens that thrive under moist conditions. However, some diseases are favored by drought. This is because when plants are stressed due to lack of moisture or excessive heat, they become more susceptible to these diseases. This article presents examples of diseases of agronomic crops favored by drought and how to manage them. Data are provided on the effect of dry or wet conditions on the profitability of applying …

Grain Storage Management To Minimize Mold And Mycotoxins, Thomas W. Dorn, Tamra A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

As most dryland corn producers are aware, the dry and hot growing season in 2012 resulted in reduced corn yields with moderately lower test weights. Along with the reduced test weights are concerns about potential mycotoxin contamination in the drought-stressed grain.

The only way to know for sure if there are mycotoxins in your grain and which specific mycotoxins are present is to collect representative grain samples and have them tested by a certified laboratory.

Many species of fungi can cause ear rot diseases and molding of grain. Most of these fungi become associated with the grain in the field …

A Virus-Encoded Potassium Ion Channel Is A Structural Protein In The Chlorovirus Paramecium Bursaria Chlorella Virus 1 Virion, Giulia Romani, Adrianna Piotrowski, Stefan Hillmer, James Gurnon, James L. Van Etten, Anna Morani, Gerhard Thiel, Brigitte Hertel

James Van Etten Publications

Most chloroviruses encode small K+ channels, which are functional in electrophysiological assays. The experimental finding that initial steps in viral infection exhibit the same sensitivity to channel inhibitors as the viral K+ channels has led to the hypothesis that the channels are structural proteins located in the internal membrane of the virus particles. This hypothesis was questioned recently because proteomic studies failed to detect the channel protein in virions of the prototype chlorovirus Paramecium bursaria chlorella virus 1 (PBCV-1). Here, we used a mAb raised against the functional K+ channel from chlorovirus MA-1D to search for the viral K+ channel …

Potassium Ion Channels: Could They Have Evolved From Viruses?1[W], Gerhard Thiel, Anna Moroni, Guillaume Blanc, James L. Van Etten

James Van Etten Publications

Cells communicate among themselves by electrical activity. Sophisticated membrane-embedded proteins, called ion channels, catalyze rapid, selective, and regulated ion fluxes across membranes (Hille, 2001). The resulting membrane currents are responsible for neuronal activity and the systemic propagation of electrical signals in animals. The activity of some channels is important for muscle movement in animals or growth in plants; other channels sense the concentration of physiological signals and modulate key processes in all kinds of eukaryotic cells. Among the many diverse ion channels in higher organisms, K+ channels are among the most important. One feature of K+ channels is that they …

Cellular And Molecular Aspects Of The Interaction Betwen Maize And The Anthracnose Pathogen Colletotrichum Graminicola, Maria F. Torres

Theses and Dissertations--Plant Pathology

Maize anthracnose, caused by the fungus Colletotrichum graminicola, is an economically important species contributing to major yield losses. C. graminicola is a hemibiotroph; initially it invades its host while it is alive, and then it switches to destructive necrotrophic growth and the host is killed. Establishment of compatible interactions by biotrophic pathogens is usually associated with suppression of host defenses and cell death, while necrotrophic pathogens typically secrete phytotoxic compounds and induce cell death. To understand the relationship of hemibiotrophy in C. graminicola to biotrophy and necrotrophy, I compared a compatible and an incompatible interaction, utilizing a non-pathogenic …

Overexpression/Silencing Of Selected Soybean Genes Alters Resistance To Pathogens, Mohamed H. El-Habbak

Theses and Dissertations--Plant Pathology

Plant diseases remain a major obstruction to meeting the world’s increased demand for soybean oil and protein. Reducing the losses caused by diseases in order to improve crop production is a high priority for agricultural research. The need for novel strategies for plant disease control cannot be overstated. In the present study, selected defense-related genes were silenced and/or overexpressed in soybean using a virus-based vector and the resultant plants were tested for their responses to pathogens. The first part of the study focused on Rps1k (Resistance to Phytophthora sojae) gene. The two conserved domains encoding ‘P-Loop NTPase’ and ‘PLN03210’ …

Control Of Erwinia Tracheiphila In Cucumis Melo, John R. Caudle

Theses and Dissertations--Plant and Soil Sciences

Currently there is no control of bacterial wilt disease, Erwinia tracheiphila, in susceptible cucurbit crops, once infection of the plant occurs. Conventional and organic production systems rely on insecticide applications to kill the vectors, striped and spotted cucumber beetles, Acalymma vittatum and Diabrotica undecimpunctata, respectively, prior to transmission of the pathogen which indirectly controls the disease to some extent. Physical barriers such as row covers are used to exclude the vectors from plants prior to flowering; however, pollination requirements expose plants to potential infection. Experimental field plots were developed to test various enhanced organic production systems in an …

Evaluation Of Sugar Maple Dieback In The Upper Great Lakes Region And Development Of A Forest Health Youth Education Program, Tara L. Bal

Dissertations, Master's Theses and Master's Reports - Open

Acer saccharum Marsh., is one of the most valuable trees in the northern hardwood forests. Severe dieback was recently reported by area foresters in the western Upper Great Lakes Region. Sugar Maple has had a history of dieback over the last 100 years throughout its range and different variables have been identified as being the predisposing and inciting factors in different regions at different times. Some of the most common factors attributed to previous maple dieback episodes were insect defoliation outbreaks, inadequate precipitation, poor soils, atmospheric deposition, fungal pathogens, poor management, or a combination of these. The current sugar maple …

The Effects Of Multiple Abiotic Stressors On The Susceptibility Of The Seagrass Thalassia Testudinum To Labyrinthula Sp., The Causative Agent Of Wasting Disease, Nichole Danielle Bishop

UNF Graduate Theses and Dissertations

In the past century, seagrasses have experienced massive die off episodes in what has been collectively referred to as “wasting disease.” Researchers generally agree that wasting disease is caused by a protist of the Labyrinthula genus, and that environmental stressors can make some populations of seagrasses more susceptible to infection. The purpose of this study was to examine the combined effects of elevated salinity, elevated temperature, elevated sulfide and night-time hypoxia on Thalassia testudinum health and its response to Labyrinthula sp. infection under controlled conditions. To test these effects, microcosms were utilized and individual seagrass shoots were randomly assigned to …

Variants Of Triticum Mosaic Virus Isolated From Wheat In Colorado Show Divergent Biological Behavior, Dallas L. Seifers, Satyanarayana Tatineni, Roy French

Department of Plant Pathology: Faculty Publications

Triticum mosaic virus (TriMV) is a recently discovered virus infecting wheat. We compared Colorado isolates C10-492 and C11-775 with the 06-123 isolate. Comparisons were made using enzyme-linked immunosorbent assay (ELISA), infectivity assay, host range, dry weight (DW), inoculation of ‘Mace’ wheat with temperature-sensitive resistance to Wheat streak mosaic virus, and the deduced amino acid sequence of the coat proteins (CP) and P1 proteins. Both C10-492 and C11-775 infected ‘Gallatin’ barley and, when compared with 06-123, had significantly reduced ELISA values and virus titers in wheat. Both Colorado isolates caused symptomless infections in Mace, whereas 06- 123 caused mosaic symptoms. …

Spatio-Temporal Patterns Of Pre-Harvest Brown Rot Epidemics Within Individual Peach Tree Canopies, Sydney E. Everhart, A. Askew, L. Seymour, H. Scherm

Department of Plant Pathology: Faculty Publications

Tree canopies are architecturally complex and pose several challenges for measuring and character-izing spatial patterns of disease. Recently developed methods for fine-scale canopy mapping and three-dimensional spatial pattern analysis were applied in a 3-year study to characterize spatio-temporal development of pre-harvest brown rot of peach, caused by Monilinia fructicola, in 13 trees of different maturity classes. We observed a negative correlation between an index of disease aggregation and disease incidence in the same tree (r = −0.653, P < 0.0001), showing that trees with higher brown rot incidence had lower aggregation of affected fruit in their canopies. Significant (P ≤ 0.05) within-canopy aggregation among symptomatic fruit was most pronounced for early-maturing cultivars and/or early in the epidemic. This is consistent with the notion of a greater importance of localized, within-tree sources of inoculum at the beginning of the epidemic. Four of five trees having >10 blossom blight symptoms per tree showed a significant positive spatial association of pre-harvest fruit rot to blossom blight within the …

Modifying Lignin To Improve Bioenergy Feedstocks: Strengthening The Barrier Against Pathogens?, Scott E. Sattler, Deanna L. Funnell-Harris

Department of Plant Pathology: Faculty Publications

Lignin is a ubiquitous polymer present in cell walls of all vascular plants, where it rigidifies and strengthens the cell wall structure through covalent cross-linkages to cell wall polysaccharides. The presence of lignin makes the cell wall recalcitrant to conversion into fermentable sugars for bioenergy uses.Therefore, reducing lignin content and modifying its linkages have become major targets for bioenergy feedstock development through either biotechnology or traditional plant breeding. In addition, lignin synthesis has long been implicated as an important plant defense mechanism against pathogens, because lignin synthesis is often induced at the site of pathogen attack. This article explores the …

Product Comparison Of Foliar Fungicide Efficacy On Diseases Of Field Corn In Nebraska, 2012, C. M. Schleicher, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

A foliar fungicide comparison trial was conducted at the University of Nebraska-Lincoln South Central Agricultural Laboratory near Clay Center, NE. DeKalb corn hybrid DKC 64-83, rating of “good” (6 out of 9) for gray leaf spot (GLS), “very good” (4 out of 9) for common rust (CR), and “good” (5 out of 9) for southern rust (SR), was planted on 26 Apr in 30-in. rows at a target population of 30,600 plants/A. The trial area was disked with corn as the previous year’s crop. Eleven treatments and a non-treated control were replicated six times in a randomized complete block design. …

Evaluation Of Application Timing On Stratego Yld Efficacy Of Field Corn In Nebraska, 2012, C. M. Schleicher, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

A foliar fungicide timing trial was conducted at the University of Nebraska-Lincoln South Central Agricultural Laboratory near Clay Center, NE. DeKalb corn hybrid DKC 64-83, rating of “good” (6 out of 9) for gray leaf spot (GLS), “very good” (4 out of 9) for common rust (CR), and “good” (5 out of 9) for southern rust (SR), was planted on 26 Apr in 30-in. rows at a target population of 30,600 plants/A. The trial area was disked with corn as the previous year’s crop. Five foliar fungicide treatments and a non-treated control were replicated six times in a randomized complete …

Efficacy Evaluation Of Foliar Fungicide Products On Diseases Of Field Corn In Nebraska, 2012, C. M. Schleicher, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

A foliar fungicide efficacy trial was conducted at the University of Nebraska-Lincoln South Central Agricultural Laboratory near Clay Center, NE. DeKalb corn hybrid DKC 64-83, rating of “good” (6 out of 9) for gray leaf spot (GLS), “very good” (4 out of 9) for common rust (CR), and “good” (5 out of 9) for southern rust (SR), was planted on 26 Apr in 30-in. rows at a target population of 30,600 plants/A. The trial area was disked with soybean as the previous year’s crop. Five foliar fungicide treatments and a nontreated control were replicated six times in a randomized complete …

Foliar Treatment Timing Trials For Management Of Goss’S Bacterial Wilt And Blight Of Field Corn In Nebraska, 2012, H. H. Oser, T. A. Jackson-Ziems, J. L. Brungardt

Department of Plant Pathology: Faculty Publications

One experimental hybrid, DKC 37-38, with a Goss’s wilt rating of 7 out of 9 (“poor”), was planted at the University of Nebraska Agricultural Research and Development Center (ARDC) near Mead, NE on 2 Jun. Corn was planted at 32,000 seeds per acre in a field that received minimum tillage. The previous year’s crop was corn. Each plot was 30 ft long and contained two rows spaced 30-in. apart. Alleys were cut between plots reducing plot length to 28 ft. All plots were irrigated with an overhead sprinkler center pivot irrigation system. . . . There were no significant differences …

Major Fusarium Diseases On Corn, Wheat, And Soybeans In Nebraska, Bo Liu, Loren J. Giesler, Tamra A. Jackson-Ziems, Stephen N. Wegulo, Robert M. Harveson

Department of Plant Pathology: Faculty Publications

Fusarium species have been associated with many important diseases of corn, wheat, and soybean, causing significant yield loss in Nebraska; some produce mycotoxins that are harmful to both human and animal consumers. These pathogens are very common in agricultural field soil across the Midwest and cause numerous types of diseases.