Plant Pathology Commons^™

Effectiveness Of Foliar Fungicides By Timing On Hybrid Corn, Alison E. Robertson, John M. Shriver, David Rueber

Northern Research and Demonstration Farm

Fungicide use on hybrid corn has increased considerably in the past several growing seasons, primarily due to reports of increased yields, even in the absence of disease and higher corn prices. A number of fungicides are registered for use on corn. The objectives of this project were to 1) assess the effect of timing of application of fungicides on standability, 2) evaluate the yield response of hybrid corn to foliar fungicide application, and 3) discern differences, if any, between fungicide products.

Efficacy Evaluation Of Foliar Fungicides In Field Corn With Low Disease Pressure In Central Nebraska, 2011, C. M. Schleicher, T. A. Jackson

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 62-54, rating of “good” (6 out of 9) for gray leaf spot (GLS) and “excellent” (2 out of 9) for common rust (CR), was planted on 3 May in 30 in. rows with a target population of 32,000 plants/A. The trial area was disked with a crop history of seven years of continuous corn. On 9 May before plant emergence, a herbicide program of Roundup (1 pt/A), Verdict (16 fl oz/A) and Atrazine (1 lb/A) was …

Morphogenetic And Developmental Functions Of The Aspergillus Nidulans Homologues Of The Yeast Bud Site Selection Proteins Bud4 And Axl2, Haoyu Si, William R. Rittenour, Kaimei Xu, Mark Nicksarlian, Ana M. Calvo, Steven D. Harris

Department of Plant Pathology: Faculty Publications

The yeast bud site selection system represents a paradigm for understanding how fungal cells regulate the formation of a polarity axis. In Saccharomyces cerevisiae, Bud4 and Axl2 are components of the axial bud site marker. To address the possibility that these proteins regulate cellular morphogenesis in filamentous fungi, we have characterized homologues of Bud4 and Axl2 in Aspergillus nidulans. Our results show that Bud4 is involved in septum formation in both hyphae and developing conidiophores. Whereas Axl2 appears to have no obvious role in hyphal growth, it is required for the regulation of phialide morphogenesis during conidiation. In …

Efficacy Evaluation Of Foliar Fungicide Application Timing In Field Corn In Central Nebraska, 2011, C. M. Schleicher, T. A. Jackson

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. DeKalb corn hybrid DKC 62-54, rating of “good” (6 out of 9) for gray leaf spot (GLS) and “excellent” (2 out of 9) for common rust (CR), was planted on 3 May in 30 in. rows with a target population of 32,000 plants/A. The trial area was disked with a crop history of seven years of continuous corn. On 9 May before plant emergence, a herbicide program of Roundup (1 pt/A), Verdict (16 fl oz/A) and Atrazine (1 lb/A) …

Sunflower Disease Profiles I: Foliar Diseases, Robert M. Harveson, Loren J. Giesler, Tamra A. Jackson, Bo Liu, Stephen N. Wegulo, Kevin A. Korus

Department of Plant Pathology: Faculty Publications

Extension Circular 1900 (EC1900).

Photographs and disease descriptions of Viruses, Apical Chlorosis, Downy Mildew, Rust, Alternia Leaf Spot, and Bacterial Leaf Spot.

Critical Roles Of Rna-Binding Proteins In Mirna Biogenesis In Arabidopsis, Guodong Ren, Bin Yu

Center for Plant Science Innovation: Faculty Publications

MicroRNAs (miRNAs) are key regulators of gene expression and play critical roles in modulating metabolism, development and physiology in animals and plants. miRNA levels are transcriptionally and post-transcriptionally controlled for their proper function. Recent studies have shown that RNA-binding proteins play important roles in producing miRNAs by affecting the accurate and/or efficient processing of precursors of miRNAs. Many of these RNA-binding proteins also have roles in general RNA metabolism, indicating potential connections between miRNA biogenesis and other RNA metabolism. Here, we focus on the function of several RNA-binding proteins in miRNA biogenesis in Arabidopsis.

Post-Transcriptional Control Of Mirna Abundance In Arabidopsis, Guodong Ren, Bin Yu

Center for Plant Science Innovation: Faculty Publications

MicroRNAs (miRNAs) are a class of small non-coding RNAs (small RNAs) that are 20–24nt in length and predominantly repress gene expression at post-transcriptional levels. They regulate many biological processes including development, metabolism and physiology. Numerous studies have revealed that the steady-state levels of miRNA are under sophisticated control to ensure their proper function. In this review, we summarize recent advances on regulation of miRNA processing and stability in plants.

Uridylation Of Mirnas By Hen1 Suppressor1 In Arabidopsis, Guodong Ren, Xuemei Chen, Bin Yu

Center for Plant Science Innovation: Faculty Publications

HEN1-mediated 2′-O-methylation has been shown to be a key mechanism to protect plant microRNAs (miRNAs) and small interfering RNAs (siRNAs) as well as animal piwi-interacting RNAs (piRNAs) from degradation and 3′ terminal uridylation [1–8]. However, enzymes uridylating unmethylated miRNAs, siRNAs, or piRNAs in hen1 are unknown. In this study, a genetic screen identified a second-site mutation hen1 suppressor1-2 (heso1-2) that partially suppresses the morphological phenotypes of the hypomorphic hen1-2 allele and the null hen1-1 allele in Arabidopsis. HESO1 encodes a terminal nucleotidyl transferase that prefers to add untemplated uridine to the 3′ end of RNA, which is …

The Dna- And Rna-Binding Protein Factor Of Dna Methylation 1 Requires Xh Domain-Mediated Complex Formation For Its Function In Rna-Directed Dna Methylation, Meng Xie, Guodong Ren, Chi Zhang, Bin Yu

Center for Plant Science Innovation: Faculty Publications

Studies have identified a sub-group of SGS3-LIKE proteins including FDM1–5 and IDN2 as key components of RNA-directed DNA methylation pathway (RdDM). Although FDM1 and IDN2 bind RNAs with 5' overhangs, their functions in the RdDM pathway remain to be examined. Here we show that FDM1 interacts with itself and with IDN2. Gel filtration suggests that FDM1 may exist as a homodimer in a heterotetramer complex in vivo. The XH domain of FDM1 mediates the FDM1–FDM1 and FDM1–IDN2 interactions. Deletion of the XH domain disrupts FDM1 complex formation and results in loss-of-function of FDM1. These results demonstrate that XH domainmediated …

Metabolic And Gene Expression Changes Triggered By Nitrogen Deprivation In The Photoautotrophically Grown Microalgae Chlamydomonas Reinhardtii And Coccomyxa Sp. C-169, Joseph Msanne, Di Xu, Anji Reddy Konda, J. Armando Casas-Mollano, Tala Awada, Edgar B. Cahoon, Heriberto Cerutti

Center for Plant Science Innovation: Faculty Publications

Microalgae are emerging as suitable feedstocks for renewable biofuel production. Characterizing the metabolic pathways involved in the biosynthesis of energy-rich compounds, such as lipids and carbohydrates, and the environmental factors influencing their accumulation is necessary to realize the full potential of these organisms as energy resources. The model green alga Chlamydomonas reinhardtii accumulates significant amounts of triacylglycerols (TAGs) under nitrogen starvation or salt stress in medium containing acetate. However, since cultivation of microalgae for biofuel production may need to rely on sunlight as the main source of energy for biomass synthesis, metabolic and gene expression changes occurring in Chlamydomonas and …

Molecular And Biochemical Characterization Of Oleate- And Glycerol-3-Phosphate-Regulated Signaling In Plants, Mihir Kumar Mandal

Theses and Dissertations--Plant Pathology

Oleic acid (18:1), a monounsaturated fatty acid (FA), is synthesized upon desaturation of stearic acid (18:0) and this reaction is catalyzed by the plastidal enzyme stearoyl-acyl carrier protein-desaturase (SACPD). A mutation in the SSI2/FAB2 encoded SACPD lowers 18:1 levels, which correlates with induction of various resistance (R) genes and increased resistance to pathogens. Genetic and molecular studies have identified several suppressors of ssi2 which restore altered defense signaling either by normalizing 18:1 levels or by affecting function(s) of a downstream component. Characterization of one such ssi2 suppressor mutant showed that it is required downstream of low 18:1-mediated constitutive …

Tritimovirus P1 Functions As A Suppressor Of Rna Silencing And An Enhancer Of Disease Symptoms, Brock A. Young, Drake C. Stenger, Feng Qu, T. Jack Morris, Satyanarayana Tatineni, Roy French

Department of Plant Pathology: Faculty Publications

Wheat streak mosaic virus (WSMV) is an eriophyid mite-transmitted virus of the genus Tritimovirus, family Potyviridae. Complete deletion of helper component-proteinase (HC-Pro) has no effect on WSMV virulence or disease synergism, suggesting that a different viral protein suppresses RNA silencing. RNA silencing suppression assays using Nicotiana benthamiana 16C plants expressing GFP were conducted with each WSMV protein; only P1 suppressed RNA silencing. Accumulation of GFP siRNAs was markedly reduced in leaves infiltrated with WSMV P1 at both 3 and 6 days post infiltration relative to WSMV HC-Pro and the empty vector control. On the other hand, helper component-proteinase …

Evaluation Of Application Timing Efficacy Of Evito Fungicide On Field Corn In Nebraska, 2010, C. M. Schleicher, T. A. Jackson

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. DeKalb corn hybrid DKC 61-69, rating of “good” (5 out of 9) for gray leaf spot and “very good” (3 out of 9) for common rust, was planted on 29 Apr in 30-in. rows with a target population of 30,000 plants/A. The trial area was disked the previous fall with a crop history of six years of continuous corn. Three treatments and a non-treated control were replicated six times in a randomized complete block design. Each plot was four …

Evaluation Of Foliar Fungicide Application Timing On Efficacy Of Field Corn At Wcrec In Western Nebraska, 2011, C. M. Schleicher, C. Langemeier, G. Kruger, T. A. Jackson-Ziems

Department of Plant Pathology: Faculty Publications

A foliar fungicide efficacy timing trial was conducted at the University of Nebraska-Lincoln West Central Research and Extension Center at North Platte, NE. NuTech corn hybrid 3A513, rating of 5 out of 9 (1=best, 9=worst) for gray leaf spot was planted on 10 May in 30 in. rows with a target population of 32,000 plants/A. The trial area was disked prior to planting with corn as the previous year’s crop. Furrows were built in season for flood irrigation. A herbicide program of Lumax (2.5 qt/A) + Atrazine (1 lb/A) + Glystar (20 oz/A) was applied on 25 Apr. 200 lb …

Evaluation Of Foliar Fungicide Application Timing On Efficacy Of Field Corn At Scal In Central Nebraska, 2011, 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. DeKalb corn hybrid DKC 62-54, rating of “good” (6 out of 9) for gray leaf spot (GLS) and “excellent” (2 out of 9) for common rust (CR), was planted on 5 May in 30 in. rows with a target population of 32,000 plants/A. The trial area had soybean as the previous year’s crop. On 9 May before plant emergence, a herbicide program of Roundup (1 pt/A), Verdict (16 fl oz/A) and Atrazine (1 lb/A) was applied to the trial …

Soybean Disease Profiles Ii: Stem And Root Rot Diseases, Loren J. Giesler, Robert M. Harveson, Tamra A. Jackson-Ziems, Kevin A. Korus, Bo Liu, Stephen N. Wegulo

Department of Plant Pathology: Faculty Publications

Extension Circular 1904 (EC1904).

Photographs and disease descriptions of Brown Stem Rot (BSR), Charcoal Rot, Fusarium Wilt and Root Rot, Phytophthora Root and Stem Rot, Pod and Stem Blight, Phomopsis Seed Decay, Rhizoctonia Root and Cortical Rot, Sclerotinia Stem Rot, Seedling Blights, Soybean Cyst Nematode (SCN), Stem Canker, and Sudden Death Syndrome (SDS).

Corn Disease Profile Iii: Ear Rot Diseases And Grain Molds, Tamra A. Jackson-Ziems, Loren J. Giesler, Robert M. Harveson, Kevin A. Korus, Bo Liu, Stephen N. Wegulo

Department of Plant Pathology: Faculty Publications

Extension Circular 1901 (EC1901).

Under certain conditions, corn ear rot and grain mold diseases are common and can lead to loss of grain quality. Moldy grain can be docked or rejected at the elevator. Additionally, some ear and grain pathogens may produce secondary metabolites called mycotoxins, which are toxic to animals and humans consuming the contaminated grain. Mycotoxin-contaminated grain can also be docked or rejected. Mycotoxin production may start in the field and continue after harvest, or it may start during storage if mold infection begins there. When grain storage is necessary, drying grain to less than 15 percent moisture …

Sunflower Disease Profiles Ii: Head And Stalk Rots And Wilts, Robert M. Harveson, Loren J. Giesler, Tamra A. Jackson, Bo Liu, Stephen N. Wegulo, Kevin A. Korus

Department of Plant Pathology: Faculty Publications

Extension Circular 1902 (EC1902).

Photographs and disease descriptions of Phoma/Phomopsis Stalk Rots, Bacterial Stalk Rot, Verticillium Wilt, Rhizopus Head Rot, and White Mold/Sclerotina Diseases.

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

Department of Plant Pathology: Faculty Publications

Goss's Bacterial Wilt and Blight ... Symptoms ... Management ... 2011 Survey ... Literature Cited

Gray Leaf Spot

Seedling Diseases and Stalk/Crown Root Diseases

More Resources

Factors Influencing Deoxynivalenol Accumulation In Small Grain Cereals, Stephen N. Wegulo

Department of Plant Pathology: Faculty Publications

Deoxynivalenol (DON) is a mycotoxin produced by the plant pathogenic fungi Fusarium graminearum and F. culmorum. These and other closely related fungi cause a disease known as Fusarium head blight (FHB) in small grain cereals. Other mycotoxins produced by FHB-causing fungi include nivalenol, T-2 toxin, and zearalenone. Ingestion of mycotoxin-contaminated food and feed can lead to toxicosis in humans and animals, respectively. DON is the predominant and most economically important of these mycotoxins in the majority of small grain-producing regions of the world. This review examines the factors that influence DON accumulation in small grain cereals from an agricultural perspective. …