Plant Pathology Commons^™

Hydraulic Mechanisms Of Fungal-Induced Dieback In A Keystone Chaparral Species During Unprecedented Drought In California, Natalie M. Aguirre, Marissa E. Ochoa, Helen I. Holmlund, Frank E. Ewers, Stephen D. Davis

Seaver College Research And Scholarly Achievement Symposium

Between 2012-2016, southern California experienced unprecedented drought that caused dieback in Malosma laurina, a keystone species of chaparral shrub communities. Dieback was especially severe in coastal exposures of the Santa Monica Mountains, leading to whole plant mortality exceeding 50% at some sites. We hypothesized that the endophytic fungus causing the dieback, Botryosphaeria dothidea, was successful in invading the xylem tissue of M. laurina because of protracted water stress, carbon starvation, or a combination of the two. We tested these possibilities in a controlled pot experiment by comparing three treatments, each inoculated with the fungus: (1) irrigated controls (2) …

Virus-Mediated Suppression Of Host Non-Self Recognition Facilitates Horizontal Transmission Of Heterologous Viruses, Songsong Wu, Jiasen Cheng, Yanping Fu, Tao Chen, Daohong Jiang, Said A. Ghabrial, Jiatao Xie

Plant Pathology Faculty Publications

Non-self recognition is a common phenomenon among organisms; it often leads to innate immunity to prevent the invasion of parasites and maintain the genetic polymorphism of organisms. Fungal vegetative incompatibility is a type of non-self recognition which often induces programmed cell death (PCD) and restricts the spread of molecular parasites. It is not clearly known whether virus infection could attenuate non-self recognition among host individuals to facilitate its spread. Here, we report that a hypovirulence-associated mycoreovirus, named Sclerotinia sclerotiorum mycoreovirus 4 (SsMYRV4), could suppress host non-self recognition and facilitate horizontal transmission of heterologous viruses. We found that cell death in …

Draft Genome Sequence Of Cercospora Sojina Isolate S9, A Fungus Causing Frogeye Leaf Spot (Fls) Disease Of Soybean, Fanchang Zeng, Chaofan Wang, Guirong Zhang, Junmei Wei, Carl A. Bradley, Ray Ming

Plant Pathology Faculty Publications

Fungi are the causal agents of many of the world's most serious plant diseases causing disastrous consequences for large-scale agricultural production. Pathogenicity genomic basis is complex in fungi as multicellular eukaryotic pathogens. The fungus Cercospora sojina is a plant pathogen that threatens global soybean supplies. Here, we report the genome sequence of C. sojina strain S9 and detect genome features and predicted genomic elements. The genome sequence of C. sojina is a valuable resource with potential in studying the fungal pathogenicity and soybean host resistance to frogeye leaf spot (FLS), which is caused by C. sojina. …

The Soy-Derived Peptide Lunasin Inhibits Invasive Potential Of Melanoma Initiating Cells, Chris Shidal, Jun-Ichi Inaba, Kavitha Yaddanapudi, Keith R. Davis

Plant Pathology Faculty Publications

Lunasin is a 44 amino acid peptide with multiple functional domains including an aspartic acid tail, an RGD domain, and a chromatin-binding helical domain. We recently showed that Lunasin induced a phenotype switch of cancer initiating cells (CIC) out of the stem compartment by inducing melanocyte-associated differentiation markers while simultaneously reducing stem-cell-associated transcription factors. In the present study, we advance the hypothesis that Lunasin can reduce pools of melanoma cells with stem cell-like properties, and demonstrate that Lunasin treatment effectively inhibits the invasive potential of CICs in vitro as well as in vivo in a mouse experimental metastasis model. Mice …

Proceedings Of The 44th Annual Meeting, Southern Soybean Disease Workers (March 8-9, 2017, Pensacola Beach, Florida), Terry Spurlock, Trey Price, Heather M. Kelly, Danise Beadle, Patricia Bollich, Tom Allen

Southern Soybean Disease Workers: Conference Proceedings

Contents

Agenda for March 8-9, 2017

Contributed papers

Soybean cyst nematode: current status, challenges and opportunities. G Tylka and K Bissonnette

Updates of the 2nd SCN (Soybean Cyst Nematode) Coalition. Albert Tenuta

Developing management zones for nematodes in soybean. C Overstreet, EC McGawley, DM Xavier-Mis, and M Kularathna

Microbial communities associated with long-term tillage and fertilizer management practices. AY Srour, J Hackman, RL Cook, JP Bond, and AM Fakhoury

Microbial profile of SDS-suppressive soils in soybean fields. AY Srour, LFS Leonardo, DK Malvick, JP Bond, and AM Fakhoury

Understanding the phytobiome; using strip trials and spatial analysis to determine concomitant …

The Lx Report Of The Bean Improvement Cooperative No. 60, March 2017.

United States Department of Agriculture-Agricultural Research Service / University of Nebraska-Lincoln: Faculty Publications

CONTENTS

LX Annual Report of the Bean Improvement Cooperative xi

BIC Coordinating Committee Membership - 1957 to 2017 . xii

BIC Meritorious Service and Distinguished Achievement Award Recipients - 1957 to 2015 xiii

BIC Awards Nomination Request for 2017 xvi

BIC/NAPIA Meeting in 2017 . xix

In Memory of Guillermo E. Galvez-Enriquez xx

RESEARCH PAPERS FOR 2017

OPTIMIZING SPORULATION OF Pseudocercospora griseola IN VITRO • Paula F. de Pádua1, Rafael Pereira1, Luanna B. W. Gomes1 and Elaine A. de Souza1* 1

FINE MAPPING THE BROAD SPECTRUM ANTHRACNOSE RESISTANCE GENE IN AMENDOIM CAVALO 3 • Gilio, T.A.S.1, Oscar P. Hurtado-Gonzales2, Giseli …

Towards The Development Of A Sustainable Soya Bean-Based Feedstock For Aquaculture, Hyunwoo Park, Steven Weier, Fareha Razvi, Pamela A. Peña, Neil A. Sims, Jennica Lowell, Cory Hungate, Karma Kissinger, Gavin Key, Paul Fraser, Jonathan Napier, Edgar B. Cahoon, Thomas Clemente

Center for Plant Science Innovation: Faculty Publications

Soya bean (Glycine max (L.) Merr.) is sought after for both its oil and protein components. Genetic approaches to add value to either component are ongoing efforts in soya bean breeding and molecular biology programmes. The former is the primary vegetable oil consumed in the world. Hence, its primary usage is in direct human consumption. As a means to increase its utility in feed applications, thereby expanding the market of soya bean coproducts, we investigated the simultaneous displacement of marine ingredients in aquafeeds with soya bean-based protein and a high Omega-3 fatty acid soya bean oil, enriched with alpha-linolenic …

Novel Gene-Sequence Markers For Isolate Tracking Within Monilinia Fructicola Lesions, Madeline E. Dowling, Guido Schnabel, Harriet G. Boatwright, Sydney E. Everhart

Department of Plant Pathology: Faculty Publications

Background: Monilinia fructicola is a diverse pathogen of pome and stone fruits that causes severe economic losses each year. However, little is known about inoculum flow within or between orchards and pathogen establishment in an orchard, because few methods exist for detecting diversity or tracking isolates over time. SSR loci are an effective option, but may be confounded by a high degree of mutability and potential sensitivity to abiotic stress.

Results: Through transcriptome analysis, we identified novel markers mrr1, DHFR and MfCYP01 and validated stability of these markers under fungicide stress in natural infection sites. Nucleotide variation …

Host Tissue Environment Directs Activities Of An Epichloë Endophyte, While It Induces Systemic Hormone And Defense Responses In Its Native Perennial Ryegrass Host, Jan Schmid, Robert Day, Ningxin Zhang, Pierre-Yves Dupont, Murray P. Cox, Christopher L. Schardl, Niki Minards, Neil Moore, Daniel R. Harris, Yanfei Zhou

Plant Pathology Faculty Publications

Increased resilience of pasture grasses mediated by fungal Epichloë endophytes is crucial to pastoral industries. The underlying mechanisms are only partially understood and likely involve very different activities of the endophyte in different plant tissues and responses of the plant to these. We analyzed the transcriptomes of Epichloë festucae and its host, Lolium perenne, in host tissues of different function and developmental stages. The endophyte contributed approximately 10× more to the transcriptomes than to the biomass of infected tissues. Proliferating mycelium in growing host tissues highly expressed genes involved in hyphal growth. Nonproliferating mycelium in mature plant tissues, transcriptionally …

A Comparative Genomic Analysis Of Putative Pathogenicity Genes In The Host-Specific Sibling Species Colletotrichum Graminicola And Colletotrichum Sublineola, Ester A. S. Buiate, Katia Viana Xavier, Neil Moore, Maria F. Torres, Mark L. Farman, Christopher L. Schardl, Lisa J. Vaillancourt

Plant Pathology Faculty Publications

Background: Colletotrichum graminicola and C. sublineola cause anthracnose leaf and stalk diseases of maize and sorghum, respectively. In spite of their close evolutionary relationship, the two species are completely host-specific. Host specificity is often attributed to pathogen virulence factors, including specialized secondary metabolites (SSM), and small-secreted protein (SSP) effectors. Genes relevant to these categories were manually annotated in two co-occurring, contemporaneous strains of C. graminicola and C. sublineola. A comparative genomic and phylogenetic analysis was performed to address the evolutionary relationships among these and other divergent gene families in the two strains.

Results: Inoculation of maize with C. sublineola …

Three-Dimensional Imaging Of The Intracellular Assembly Of A Functional Viral Rna Replicase Complex, Isabel Fernández De Castro, José J. Fernández, Daniel Barajas, Peter D. Nagy, Cristina Risco

Plant Pathology Faculty Publications

Positive-strand RNA viruses, which can be devastating pathogens in humans, animals and plants, replicate their genomes on intracellular membranes. Here, we describe the three-dimensional ultrastructural organization of a tombusvirus replicase in yeast, a valuable model for exploring virus–host interactions. We visualized the intracellular distribution of a viral replicase protein using metal-tagging transmission electron microscopy, a highly sensitive nanotechnology whose full potential remains to be developed. These three-dimensional images show how viral replicase molecules are organized when they are incorporated into the active domains of the intracellular replication compartment. Our approach provides a means to study protein activation mechanisms in cells …

The Family Rhabdoviridae: Mono- And Bipartite Negative-Sense Rna Viruses With Diverse Genome Organization And Common Evolutionary Origins, Ralf G. Dietzgen, Hideki Kondo, Michael M. Goodin, Gael Kurath, Nikos Vasilakis

Plant Pathology Faculty Publications

The family Rhabdoviridae consists of mostly enveloped, bullet-shaped or bacilliform viruses with a negative-sense, single-stranded RNA genome that infect vertebrates, invertebrates or plants. This ecological diversity is reflected by the diversity and complexity of their genomes. Five canonical structural protein genes are conserved in all rhabdoviruses, but may be overprinted, overlapped or interspersed with several novel and diverse accessory genes. This review gives an overview of the characteristics and diversity of rhabdoviruses, their taxonomic classification, replication mechanism, properties of classical rhabdoviruses such as rabies virus and rhabdoviruses with complex genomes, rhabdoviruses infecting aquatic species, and plant rhabdoviruses with both mono- …

The Magnaporthe Oryzae Nitrooxidative Stress Response Suppresses Rice Innate Immunity During Blast Disease, Margarita Marroquin-Guzman, David E. Hartline, Janet D. Wright, Christian G. Elowsky, Travis J. Bourret, Richard A. Wilson

Department of Plant Pathology: Faculty Publications

Understanding how microorganisms manipulate plant innate immunity and colonize host cells is a major goal of plant pathology. Here, we report that the fungal nitrooxidative stress response suppresses host defenses to facilitate the growth and development of the important rice pathogen Magnaporthe oryzae in leaf cells. Nitronate monooxygenases encoded by NMO genes catalyze the oxidative denitrification of nitroalkanes. We show that the M. oryzae NMO2 gene is required for mitigating damaging lipid nitration under nitrooxidative stress conditions and, consequently, for using nitrate and nitrite as nitrogen sources. On plants, the Δnmo2 mutant strain penetrated host cuticles like wild type, …

The Morphogenesis-Related Ndr Kinase Pathway Of Colletotrichum Orbiculare Is Required For Translating Plant Surface Signals Into Infection-Related Morphogenesis And Pathogenesis, Sayo Kodama, Junya Ishizuka, Ito Miyashita, Takaaki Ishii, Takumi Nishiuchi, Hideto Miyoshi, Yasuyuki Kubo

Department of Plant Pathology: Faculty Publications

Plant infection by pathogenic fungi involves the differentiation of appressoria, specialized infection structures, initiated by fungal sensing and responding to plant surface signals. How plant fungal pathogens control infection-related morphogenesis in response to plant-derived signals has been unclear. Here we showed that the morphogenesis-related NDR kinase pathway (MOR) of the cucumber anthracnose fungus Colletotrichum orbiculare is crucial for appressorium development following perception of plant-derived signals. By screening of random insertional mutants, we identified that the MOR element CoPag1 (Perish-in-theabsence-of-GYP1) is a key component of the plant-derived signaling pathway involved in appressorium morphogenesis. Constitutive activation of the NDR kinase …

Lsp Family Proteins Regulate Antibiotic Biosynthesis In Lysobacter Enzymogenes Oh11, Ruping Wang, Huiyong Xu, Yangyang Zhao, Juan Zhang, Gary Y. Yuen, Guoliang Qian, Fengquan Liu

Department of Plant Pathology: Faculty Publications

Ax21 family proteins have been shown to play regulatory roles in plant- and animal-pathogenic species in the bacterial family Xanthomonadaceae, but the protein have not been investigated previously in the non-pathogenic members of this bacterial family. Lysobacter enzymogenes, is a non-pathogenic species known for its capacity as a biocontrol agent of plant pathogens. It is also noted for the production of antimicrobial secondary metabolites, heat stable antifungal factor (HSAF) and WAP-8294A2, that have potential for agricultural and pharmaceutical applications. The species also displays type IV pili-dependent twitching motility and the production of multiple extracellular lytic enzymes as additional biocontrol-related traits. …

Species Delimitation And Description Of Mesocriconema Nebraskense N. Sp. (Nematoda: Criconematidae), A Morphologically Cryptic, Parthenogenetic Species From North American Grasslands, Magdalena Olson, Timothy Harris, Rebecca Higgins, Peter Mullin, Kirsten Powers, Sean Olson, Thomas O. Powers

Department of Plant Pathology: Faculty Publications

Nematode surveys of North American grasslands conducted from 2010 to 2015 frequently recovered a species of criconematid nematode morphologically resembling Mesocriconema curvatum. These specimens were recovered from remnant native prairies in the central tallgrass ecoregion of North America, and not from surrounding agroecosystems. Historical records indicate that M. curvatum is a cosmopolitan species feeding on a wide range of agronomic and native plants. DNA barcoding indicates North American grasslands contain at least 10 phylogenetically distinct lineages of Mesocriconema that resemble, but are not, M. curvatum. Analysis of the two most common lineages reveals two distinctly different population structures. …

Corn Disease Update, Tamra A. Jackson-Ziems, Terra Hartman

Department of Plant Pathology: Faculty Publications

Several diseases were important in the 2016 Nebraska corn crop and impacted yield in some areas. Many of these diseases developed as a result of extreme weather events that were favorable for disease development. Most of those diseases are caused by pathogens that are capable of survival in the crop debris or residue, and so they are more likely to develop again in future years if environmental conditions are favorable again. This article summarizes some of Nebraska’s most important corn disease problems in 2016, tips for diagnosis, and management strategies.

Bacterial Leaf Streak

Gray Leaf Spot

Southern Rust

Stalk Rot …

Structure Of The Chlorovirus Pbcv-1 Major Capsid Glycoprotein Determined By Combining Crystallographic And Carbohydrate Molecular Modeling Approaches, Cristina De Castro, Thomas Klose, Immacolata Speciale, Rosa Lanzetta, Antonio Molinaro, James L. Van Etten, Michael G. Rossmann

James Van Etten Publications

The glycans of the major capsid protein (Vp54) of Paramecium bursaria chlorella virus (PBCV-1) were recently described and found to be unusual. This prompted a reexamination of the previously reported Vp54 X-ray structure. A detailed description of the complete glycoprotein was achieved by combining crystallographic data with molecular modeling. The crystallographic data identified most of the monosaccharides located close to the protein backbone, but failed to detect those further from the glycosylation sites. Molecular modeling complemented this model by adding the missing monosaccharides and examined the conformational preference of the whole molecule, alone or within the crystallographic environment. Thus, combining …

An 18s Rdna Perspective On The Classification Of Criconematoidea, Thomas O. Powers, Timothy Harris, Rebecca Higgins, Peter Mullin, Kirsten Powers

Department of Plant Pathology: Faculty Publications

In the nematode family Criconematidae, a taxonomy primarily based on cuticle characters has created classifications that are notoriously volatile. Molecular characters may lead to their stabilization. A phylogenetic tree of Criconematoidea was constructed using 166 new near full-length 18S rDNA sequences and 58 sequences from GenBank. Bayesian and maximum likelihood (ML) analyses produced trees with similar topologies. Major features include a strongly supported clade that includes Criconematidae and Hemicycliophoridae, excluding Paratylenchidae and Tylenchulidae. Another well-supported clade groups Criconema, Ogma, Crossonema, and Hemicriconemoides plus Xenocriconemella, combining nematodes with cuticular scales with those without scales at any life stage. Mesocriconema, Discocriconemella limitanea, …

Enhancing Soybean Photosynthetic Co2 Assimilation Using A Cyanobacterial Membrane Protein, Ictb, William T. Hay, Saadia Bihmidine, Nedim Mutlu, Khang Le Hoang, Tala Awada, Donald P. Weeks, Thomas Clemente, Stephen P. Long

Center for Plant Science Innovation: Faculty Publications

Soybean C₃ photosynthesis can suffer a severe loss in efficiency due to photorespiration and the lack of a carbon concentrating mechanism (CCM) such as those present in other plant species or cyanobac-teria. Transgenic soybean (Glycine max cv. Thorne) plants constitutively expressing cyanobacterial ictB (inorganic carbon transporter B) gene were generated using Agrobacterium-mediated transformation. Although more recent data suggest that ictB does not actively transport HCO3-/CO2, there is nevertheless mounting evidence that transformation with this gene can increase higher plant photosynthesis. The hypothesis that expression of the ictB gene would improve photosynthesis, biomass production and seed yield in soybean …