Plant Pathology Commons^™

Elucidating The Role Of Highly Homologous Nicotiana Benthamiana Ubiquitin E2 Gene Family Members In Plant Immunity Through An Improved Virus‑Induced Gene Silencing Approach, Bangjun Zhou, Lirong Zeng

Department of Plant Pathology: Faculty Publications

Background: Virus-induced gene silencing (VIGS) has been used in many plant species as an attractive post transcriptional gene silencing (PTGS) method for studying gene function either individually or at large-scale in a high-throughput manner. However, the specificity and efficiency for knocking down members of a highly homologous gene family have remained to date a significant challenge in VIGS due to silencing of off-targets. Results: Here we present an improved method for the selection and evaluation of gene fragments used for VIGS to specifically and efficiently knock down members of a highly homologous gene family. Using this method, we knocked down …

The Tomato U-Box Type E3 Ligase Pub13 Acts With Group Iii Ubiquitin E2 Enzymes To Modulate Fls2-Mediated Immune Signaling, Bangjun Zhou, Lirong Zeng

Department of Plant Pathology: Faculty Publications

In Arabidopsis and rice, the ubiquitin ligase PUB13-mediated protein degradation plays a significant role in plant pattern-triggered immunity (PTI) and flowering time control. The Arabidopsis PUB13 has been shown to attenuate the pattern recognition receptor FLS2-mediated immune signaling by ubiquitinating FLS2 and consequently promoting its degradation by the 26S proteasome. Nevertheless, the cognate ubiquitin-conjugating enzymes (E2) with which PUB13 acts to modulate FLS2-mediated PTI are unknown. To address this question, we investigate here the tomato (Solanum lycopersicum) homolog of PUB13, SlPUB13 by utilizing the recently characterized complete set of tomato E2s. Of the 13 groups of tomato E2s, …

Proteomic Analysis Of Ubiquitinated Proteins In Rice (Oryza Sativa) After Treatment With Pathogen-Associated Molecular Pattern (Pamp) Elicitors, Xiao-Lin Chen, Xin Xie, Liye Wu, Caiyun Liu, Lirong Zeng, Xueping Zhou, Feng Luo, Guo-Liang Wang, Wende Liu

Department of Plant Pathology: Faculty Publications

Reversible protein ubiquitination plays essential roles in regulating cellular processes. Although many reports have described the functions of ubiquitination in plant defense responses, few have focused on global changes in the ubiquitome. To better understand the regulatory roles of ubiquitination in rice pattern-triggered immunity (PTI), we investigated the ubiquitome of rice seedlings after treatment with two pathogen-associated molecular patterns, the fungal-derived chitin or the bacterialderived flg22, using label-free quantitative proteomics. In chitin-treated samples, 144 and 167 lysine-ubiquitination sites in 121 and 162 proteins showed increased and decreased ubiquitination, respectively. In flg22-treated samples, 151 and 179 lysine-ubiquitination sites in 118 and …

Genes For Membrane Transport Proteins: Not So Rare In Viruses, Timo Greiner, Anna Moroni, James L. Van Etten, Gerhard Thiel

James Van Etten Publications

Some viruses have genes encoding proteins with membrane transport functions. It is unknown if these types of proteins are rare or are common in viruses. In particular, the evolutionary origin of some of the viral genes is obscure, where other viral proteins have homologs in prokaryotic and eukaryotic organisms. We searched virus genomes in databases looking for transmembrane proteins with possible transport function. This effort led to the detection of 18 different types of putative membrane transport proteins indicating that they are not a rarity in viral genomes. The most abundant proteins are K+ channels. Their predicted structures vary between …

Size-Dependent Catalysis Of Chlorovirus Population Growth By A Messy Feeding Predator, John Delong, Zeina Al-Ameeli, Shelby Lyon, James L. Van Etten, David Dunigan

James Van Etten Publications

Many chloroviruses replicate in endosymbiotic zoochlorellae that are protected from infection by their symbiotic host. To reach the high virus concentrations that often occur in natural systems, a mechanism is needed to release zoochlorellae from their hosts. We demonstrate that the ciliate predator Didinium nasutum foraging on zoochlorellae-bearing Paramecium bursaria can release live zoochlorellae from the ruptured prey cell that can then be infected by chloroviruses. The catalysis process is very effective, yielding roughly 95% of the theoretical infectious virus yield as determined by sonication of P. bursaria. Chlorovirus activation is more effective with smaller Didinia, as larger …

Wheat Streak Mosaic Virus: A Century Old Virus With Rising Importance Worldwide, Khushwant Singh, Stephen N. Wegulo, Anna Skoracka, Jiban Kumar Kundu

Department of Plant Pathology: Faculty Publications

Wheat streak mosaic virus (WSMV) causes wheat streak mosaic, a disease of cereals and grasses that threatens wheat production worldwide. It is a monopartite, positive-sense, single-stranded RNA virus and the type member of the genus Tritimovirus in the family Potyviridae. The only known vector is the wheat curl mite (WCM, Aceria tosichella), recently identified as a species complex of biotypes differing in virus transmission. Low rates of seed transmission have been reported. Infected plants are stunted and have a yellow mosaic of parallel discontinuous streaks on the leaves. In the autumn, WCMs move from WSMV-infected volunteer wheat and other grass …

Efficacy Of Seed Treatments, Microbial And Biochemical Pesticides For Managing Early Tan Spot And Stripe Rust Diseases Of Wheat, Collins Bugingo

Electronic Theses and Dissertations

Wheat is a major cereal crop in the U.S.A and in the world. However, its production is hampered by a number of factors both biotic and abiotic. Foliar diseases like tan spot caused by Pyrenophora tritici-repentis and stripe rust caused by Puccinia striiformis f. sp. tritici, are economically important diseases causing over 5-55 % yield loss. To assess the efficacy of fungicide seed treatments in the management of early tan spot, two hard red spring wheat cultivars “Select” and “Brick” were treated with seedapplied commercially available combo fungicides metalaxyl + pyraclostrobin + triticonazole and difenoconazole + mefenoxam + sedaxane …

Evaluation Of Alternative Weed Hosts And Management Strategies For Soybean Cyst Nematode In South Dakota, Pawan Basnet

Electronic Theses and Dissertations

The soybean cyst nematode (SCN; Heterodera glycines, Ichinohe) is an important pathogen of soybean in South Dakota which causes significant yield losses. SCN has been found in 30 South Dakota counties as on 2017 and is estimated to cause yield loss of 1.9 Metric tons (Mt) annually. SCN has diverse crop and weed hosts as it can reproduce in several crops and weeds. The presence of Heterodera glycines (HG) types can reduce the effectiveness of SCN-resistant cultivars and the HG types reproduction on weed hosts can negate the effectiveness of crop rotation by continued build-up in the field. This …

Mac3a And Mac3b, Two Core Subunits Of The Mos4-Associated Complex, Positively Influence Mirna Biogenesis, Shengjun Li, Kan Liu, Bangjun Zhou, Mu Li, Shuxin Zhang, Lirong Zeng, Chi Zhang, Bin Yu

Center for Plant Science Innovation: Faculty Publications

MAC3A and MAC3B are conserved U-box containing proteins in eukaryotes. They are subunits of the MOS4-associated complex (MAC) that plays essential roles in plant immunity and development in Arabidopsis. However, their functional mechanisms remain elusive. Here we show that Arabidopsis thaliana MAC3A and MAC3B act redundantly in microRNA (miRNA) biogenesis. Lack of both MAC3A and MAC3B in the mac3b mac3b double mutant reduces the accumulation of miRNAs, causing elevated transcript levels of miRNA targets. mac3a mac3b also decreases the levels of primary miRNA transcripts (pri-miRNAs). However, MAC3A and MAC3B do not affect the promoter activity of genes encoding miRNAs ( …

Evaluation Of Trichoderma Spp. As Biocontrol Agents For Soybean Diseases, Jonathan Vance Lacey

Theses and Dissertations--Plant Pathology

Fungi in the genus Trichoderma have been characterized as biocontrol agents of plant pathogens since the 1930s. The use of biologicals for disease management has increased in recent years, typically marketed as a safer alternative to chemical applications. However, biologicals often lack consistent control across varying environmental conditions. To overcome the loss in efficacy due to environmental conditions, biologicals can be combined with common fungicide seed-treatments to provide improved control. Additionally, the presence of a biological organism could slow the development of a pathogen population. Greenhouse trials were conducted to determine the baseline root colonization of three Trichoderma spp. used …

Tomato Spotted Wilt Virus Nss Protein Supports Infection And Systemic Movement Of A Potyvirus And Is A Symptom Determinant, Hernan Garcia-Ruiz, Sergio M. Gabriel Peralta, Patricia A. Harte-Maxwell

Department of Plant Pathology: Faculty Publications

Plant viruses are inducers and targets of antiviral RNA silencing. To condition susceptibility, most plant viruses encode silencing suppressor proteins that interfere with antiviral RNA silencing. The NSs protein is an RNA silencing suppressor in orthotospoviruses, such as the tomato spotted wilt virus (TSWV). The mechanism of RNA silencing suppression by NSs and its role in virus infection and movement are poorly understood. Here, we cloned and tagged TSWV NSs and expressed it from a GFP-tagged turnip mosaic virus (TuMV-GFP) carrying either a wild-type or suppressor-deficient (AS9) helper component proteinase (HC-Pro). When expressed in cis, NSs restored pathogenicity and promoted …

Intermolecular Rna Recombination Occurs At Different Frequencies In Alternate Forms Of Brome Mosaic Virus Rna Replication Compartments, Hernan Garcia-Ruiz, Arturo Diaz, Paul Ahlquist

Department of Plant Pathology: Faculty Publications

Positive-strand RNA viruses replicate their genomes in membrane-bound replication compartments. Brome mosaic virus (BMV) replicates in vesicular invaginations of the endoplasmic reticulum membrane. BMV has served as a productive model system to study processes like virus-host interactions, RNA replication and recombination. Here we present multiple lines of evidence showing that the structure of the viral RNA replication compartments plays a fundamental role and that recruitment of parental RNAs to a common replication compartment is a limiting step in intermolecular RNA recombination. We show that a previously defined requirement for an RNA recruitment element on both parental RNAs is not to …

Pushing The Resolution Limit By Correcting The Ewald Sphere Effect In Single-Particle Cryo-Em Reconstructions, Dongjie Zhu, Xiangxi Wang, Qianglin Fang, James L. Van Etten, Michael G. Rossmann, Zihe Rao, Xinzheng Zhang

Department of Plant Pathology: Faculty Publications

The Ewald sphere effect is generally neglected when using the Central Projection Theorem for cryo electron microscopy single-particle reconstructions. This can reduce the resolution of a reconstruction. Here we estimate the attainable resolution and report a “block-based” reconstruction method for extending the resolution limit. We find the Ewald sphere effect limits the resolution of large objects, especially large viruses. After processing two real datasets of large viruses, we show that our procedure can extend the resolution for both datasets and can accommodate the flexibility associated with large protein complexes.

Metagenomic Analysis Of Viruses Associated With Maize Lethal Necrosis In Kenya, Mwathi Jane Wamaitha, Deepti Nigam, Solomon Maina, Francesca Stomeo, Anne Wangai, Joyce Njoki Njuguna, Timothy A. Holton, Bramwel W. Wanjala, Mark Wamalwa, Tanui Lucas, Appolinaire Djikeng, Hernan Garcia Ruiz

Department of Plant Pathology: Faculty Publications

Background: Maize lethal necrosis is caused by a synergistic co-infection of Maize chlorotic mottle virus (MCMV) and a specific member of the Potyviridae, such as Sugarcane mosaic virus (SCMV), Wheat streak mosaic virus (WSMV) or Johnson grass mosaic virus (JGMV). Typical maize lethal necrosis symptoms include severe yellowing and leaf drying from the edges. In Kenya, we detected plants showing typical and atypical symptoms. Both groups of plants often tested negative for SCMV by ELISA. Methods: We used next-generation sequencing to identify viruses associated to maize lethal necrosis in Kenya through a metagenomics analysis. Symptomatic and asymptomatic leaf samples …

Genome-Wide Analysis Of Genes Encoding Core Components Of The Ubiquitin System In Soybean (Glycine Max) Reveals A Potential Role For Ubiquitination In Host Immunity Against Soybean Cyst Nematode, Chunyu Zhang, Li Song, Mani Kant Choudhary, Bangjun Zhou, Guangchao Sun, Kyle C. Broderick, Loren Giesler, Lirong Zeng

Department of Plant Pathology: Faculty Publications

Background: Ubiquitination is a major post-translational protein modification that regulates essentially all cellular and physiological pathways in eukaryotes. The ubiquitination process typically involves three distinct classes of enzymes, ubiquitin-activating enzyme (E1), ubiquitin-conjugating enzyme (E2) and ubiquitin ligase (E3). To date, a comprehensive identification and analysis of core components comprising of the whole soybean (Glycine max) ubiquitin system (UBS) has not been reported.

Results: We performed a systematic, genome-wide analysis of genes that encode core members of the soybean UBS in this study. A total of 1431 genes were identified with high confidence to encode putative soybean UBS components, …

Tor-Autophagy Branch Signaling Via Imp1 Dictates Plant-Microbe Biotrophic Interface Longevity, Guangchao Sun, Christian Elowsky, Gang Li, Richard Wilson

Department of Plant Pathology: Faculty Publications

Like other intracellular eukaryotic phytopathogens, the devastating rice blast fungus Magnaporthe (Pyricularia) oryzae first infects living host cells by elaborating invasive hyphae (IH) surrounded by a plant-derived membrane. This forms an extended biotrophic interface enclosing an apoplastic compartment into which fungal effectors can be deployed to evade host detection. M. oryzae also forms a focal, plant membrane-rich structure, the biotrophic interfacial complex (BIC), that accumulates cytoplasmic effectors for translocation into host cells. Molecular decision-making processes integrating fungal growth and metabolism in host cells with interface function and dynamics are unknown. Here, we report unanticipated roles for the M. …

Susceptibility Genes To Plant Viruses, Hernan Garcia Ruiz

Department of Plant Pathology: Faculty Publications

Plant viruses use cellular factors and resources to replicate and move. Plants respond to viral infection by several mechanisms, including innate immunity, autophagy, and gene silencing, that viruses must evade or suppress. Thus, the establishment of infection is genetically determined by the availability of host factors necessary for virus replication and movement and by the balance between plant defense and viral suppression of defense responses. Host factors may have antiviral or proviral activities. Proviral factors condition susceptibility to viruses by participating in processes essential to the virus. Here, we review current advances in the identification and characterization of host factors …

Profile Of Genetically Modified Plants Authorized In Mexico, Mayra Teresa Garcia Ruiz, Aaron N. Knapp, Hernan Garcia Ruiz

Department of Plant Pathology: Faculty Publications

Mexico is a center of origin for several economically important plants including maize, cotton, and cocoa. Maize represents more than a food crop, has been declared a biological, cultural, agricultural and economic patrimony, and is linked to the national identity of Mexicans. In this review, we describe the historic and current use of genetically modified plants in Mexico and factors that contributed to the development of the biosafety regulation. We developed a database containing all permit applications received by the government to release genetically modified plants. A temporal and geographical analysis identified the plant species that have been authorized for …

Determination Of Vegetative Development And Flower Effect Of Transgenic Nicotiana Tabacum, Hasan Pinar, Aydin Uyun, Semih Yilmaz, Nedim Mutlu, Amitava Mitra

Department of Plant Pathology: Faculty Publications

Species and varieties in the Nicotiana genus may respond differently to photoperiodism in terms of flowering time control. These are classified as short day, neutral day and long day plants. One of these, Nicotiana tabacum cv. The Xanthi nc is a genotype which can flowering on a long day. But the genotype Kanamycin resistance can open its flowers in January when the resistance gene is transferred to the plant. On the other hand, the effect of rootstock to scion in plant species is very important. One of the issues raised is whether the transgenic plant in the rootstock is effect …