Plant Biology Commons^™

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 …

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 …

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.

Corn Disease Update, Tamra A. Jackson-Ziems, Craig B. Langemeier, Greg R. Kruger

Department of Plant Pathology: Faculty Publications

Goss's Bacterial Wilt and Blight ... Symptoms ... 2011 Survey results ... New alternate hosts identified ... Goss's Wilt Management Strategies ... More Resources ... Literature Cited

Aspergillus Ear Rot and Aflatoxin Contaminated Grain ... Table 1. FDA Action Levels for Aflatoxin in Feed and Food ... Testing for Aflatoxin ... High risk factors for aflatoxin contamination in corn ... Scouting for Aspergillus Ear Rot ... Harvest and Storage ... More Resources

Stalk Rot Diseases ... Scouting for Stalk Rot Diseases ... Management ... More Resources

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, Kevin A. Korus, Robert N. Klein

Department of Plant Pathology: Faculty Publications

Fusarium species are associated with diseases of corn, wheat, and soybean, causing significant yield loss in Nebraska. Some produce mycotoxins that are harmful to humans and animals.

False Smut Of Rice: Histological Analysis Of Infection, Liem Thi Thanh Nguyen

Graduate Theses and Dissertations

False smut of rice, caused by Ustilaginoidea virens (Cooke) Takahashi (Teleomorph: Villosiclava virens), has become a common disease in most major rice growing regions throughout the world. Considerable confusion exists regarding the infection process and the disease cycle. Therefore, a clearer understanding of pathogenesis caused by Ustilaginoidea virens is critical for future efforts to develop genetic and chemical tools to manage false smut in Arkansas and other regions of the world. The overall goal of this research was to clarify the infection process underlying false smut, with emphasis on comparing and contrasting the histological basis of root and foliar infections. …

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 …

Functional Analysis Of Three Arabidopsis Argonautes Using Slicer-Defective Mutants, Alberto Carbonell, Noah Fahlgren, Hernan Garcia-Ruiz, Kerrigan B. Gilbert, Taiowa A. Montgomery, Tammy Nguyen, Josh T. Cuperus, James C. Carrington

Department of Plant Pathology: Faculty Publications

In RNA-directed silencing pathways, ternary complexes result from small RNA-guided ARGONAUTE (AGO) associating with target transcripts. Target transcripts are often silenced through direct cleavage (slicing), destabilization through slicerindependent turnover mechanisms, and translational repression. Here, wild-type and active-site defective forms of several Arabidopsis thaliana AGO proteins involved in posttranscriptional silencing were used to examine several AGO functions, including small RNA binding, interaction with target RNA, slicing or destabilization of target RNA, secondary small interfering RNA formation, and antiviral activity. Complementation analyses in ago mutant plants revealed that the catalytic residues of AGO1, AGO2, and AGO7 are required to restore the defects …

High School Horticulture Curriculum, Margaret Maratsos

Horticulture and Crop Science

Horticulture is just one of the many topics covered in a high school agriculture curriculum, and yet, there are very few lesson plans or resources available to teachers for these classes specifically. The objectives of this project were to compile a set of lesson plans, lab plans, and tests that would emphasize interactive and investigative learning. The lesson plans were written in such a way that they reflected a certain set of standards, set down by the state of California, and were meant to serve as a bare outline of topics that would be discussed within a week’s worth of …

Enhancement Or Attenuation Of Disease By Deletion Of Genes From Citrus Tristeza Virus, Satyanarayana Tatineni, William O. Dawson

Department of Plant Pathology: Faculty Publications

Stem pitting is a common virus-induced disease of perennial woody plants induced by a range of different viruses. The phenotype results from sporadic areas of the stem in which normal xylem and phloem development is prevented during growth of stems. These alterations interfere with carbohydrate transport, resulting in reduced plant growth and yield. Citrus tristeza virus (CTV), a phloem-limited closterovirus, induces economically important stem-pitting diseases of citrus. CTV has three nonconserved genes (p33, p18, and p13) that are not related to genes of other viruses and that are not required for systemic infection of some species of citrus, which allowed …

Flight Period And Species Composition Of Sirex (Hymenoptera: Siricidae) And Associated Deladenus (Nematoda: Neotylenchidae) Within Arkansas Pine Forests, Danielle Keeler

Graduate Theses and Dissertations

The European woodwasp, Sirex noctilio F. (Hymenoptera: Siricidae), which is a known destructive pest of pine in the southern hemisphere was recently discovered in the eastern United States. Before we can understand how S. noctilio may affect pine forests throughout the United States, we need a better understanding of native Sirex and the role they play in the ecosystem. The objectives of this research were to 1) determine species composition and flight period for native Sirex; 2) confirm presence of parasitic nematodes, Deladenus (Nematoda: Neotylenchidae), within adult Sirex; 3) investigate Deladenus parasitism rates; 4) verify the number of Deladenus species …

Efficacy And Stability Of Integrating Fungicide And Cultivar Resistance To Manage Fusarium Head Blight And Deoxynivalenol In Wheat, K. T. Willyerd, C. Li, L. V. Madden, C. A. Bradley, G. C. Bergstrom, L. E. Sweets, M. Mcmullen, J. K. Ransom, A. Grybauskas, L. Osborne, S. N. Wegulo, D. E. Hershman, K. Wise, W. W. Bockus, D. Groth, R. Dill-Macky, E. Milus, P. D. Esker, K. D. Waxman, E. A. Adee, S. E. Ebelhar, B. G. Young, P. A. Paul

Department of Plant Pathology: Faculty Publications

Integration of host resistance and prothioconazole + tebuconazole fungicide application at anthesis to manage Fusarium head blight (FHB) and deoxynivalenol (DON) in wheat was evaluated using data from over 40 trials in 12 U.S. states. Means of FHB index (index) and DON from up to six resistance class–fungicide management combinations per trial (susceptible treated [S_TR] and untreated [S_UT]; moderately susceptible treated [MS_TR] and untreated [MS_UT]; moderately resistant treated [MR_TR] and untreated [MR_UT]) were used in multivariate meta-analyses, and mean log response ratios across trials were estimated and transformed to estimate mean percent control ( C ) due to the management …

The Pseudomonas Syringae Hrpj Protein Controls The Secretion Of Type Iii Translocator Proteins And Has A Virulence Role Inside Plant Cells, Emerson Crabill, Andrew Karpisek, James R. Alfano

Center for Plant Science Innovation: Faculty Publications

The bacterial plant pathogen Pseudomonas syringae injects effector proteins into plant cells via a type III secretion system (T3SS), which is required for pathogenesis. The protein HrpJ is secreted by P. syringae and is required for a fully functional T3SS. A hrpJ mutant is non-pathogenic and cannot inject effectors into plant cells or secrete the harpin HrpZ1. Here we show that the hrpJ mutant also cannot secrete the harpins HrpW1 and HopAK1 or the translocator HrpK1, suggesting that these proteins are required in the translocation (injection) of effectors into plant cells. Complementation of the hrpJ mutant with secretion incompetent HrpJ …

Effects Of Single And Double Infections Of Winter Wheat By Triticum Mosaic Virus And Wheat Streak Mosaic Virus On Yield Determinants, E. Byamukama, S. Tatineni, G. L. Hein, R. A. Graybosch, P. Stephen Baenziger, R. French, S. N. Wegulo

Department of Plant Pathology: Faculty Publications

Triticum mosaic virus (TriMV) is a recently discovered virus infecting wheat (Triticum aestivum) in the Great Plains region of the United States. It is transmitted by wheat curl mites (Aceria tosichella) which also transmit Wheat streak mosaic virus (WSMV) and Wheat mosaic virus. In a greenhouse study, winter wheat ‘Millennium’ (WSMV susceptible) and ‘Mace’ (WSMV resistant) were mechanically inoculated with TriMV, WSMV, TriMV+WSMV, or sterile water at the two-leaf growth stage. At 28 days after inoculation, final chlorophyll meter (soil plant analysis development [SPAD]) readings, area under the SPAD progress curve (AUSPC), the number of …

Host Pathogen Interactions: Is Arabidopsis Thaliana Remembered By Its Nemesis Pseudomonas Syringae?, Daniel Z. Kreiser

Lawrence University Honors Projects

Plants contain innate immune systems that deter pathogen infection. Pattern recognition receptors bind microbe-associated molecular patterns (MAMPs), triggering immunity. MAMPs are proteins exclusive to pathogens that are typically indispensable for their survival. For this reason, MAMPs cannot be mutated or removed without causing pathogen death. However, this does not necessitate constitutive expression of MAMPs. In this study, the MAMP response of Arabidopsis thaliana was utilized to determine differential detection of MAMPs expressed by Pseudomonas syringe pv. tomato DC3000 when pretreated with A. thaliana. Results demonstrated that more MAMPs are detected when P. syringae had previously encountered A. thaliana, …

Evidence Of Reduced Arbuscular Mycorrhizal Fungal Colonization In Multiple Lines Of Bt Maize, Tanya E. Cheeke, Todd N. Rosenstiel, Mitchell B. Cruzan

Biology Faculty Publications and Presentations

Premise of the Study: Insect-resistant Bacillus thuringiensis (Bt) maize is widely cultivated, yet few studies have examined the interaction of symbiotic arbuscular mycorrhizal fungi (AMF) with different lines of Bt maize. As obligate symbionts, AMF may be sensitive to genetic changes within a plant host. Previous evaluations of the impact of Bt crops on AMF have been inconsistent, and because most studies were conducted under disparate experimental conditions, the results are difficult to compare. Methods: We evaluate AMF colonization in nine Bt maize lines, differing in number and type of engineered trait, and five corresponding near-isogenic parental (P) base hybrids …

Plant Wounding And Ophiostoma Mitovirus 3a (Omv3a) Influence Infection Of Creeping Bentgrass By Sclerotinia Homoeocarpa, Angela M. Orshinsky, Michael J. Boehm, Greg J. Boland

Department of Plant Pathology: Faculty Publications

Colonization and lesion development by virulent, asymptomatic and hypovirulent isolates of Sclerotinia homoeocarpa on nonwounded (NW) and wounded (W) leaves of creeping bentgrass were characterized. Hypovirulent and asymptomatic isolates contain the fungal virus, Ophiostoma mitovirus 3a, and virulent isolates are virus-free. On NW leaves, all isolates infected leaves with appressoria along cell walls and through stomata by 48 hours post-inoculation (hpi). Inter- and intracellular hyphae formed on heavily colonized, NW leaves at 96 hpi. Wound-inoculated grass had a colonization front characterized by inter- and intracellular hyphal colonization within nonsymptomatic tissues at 8 hpi by direct infection of the wound …