Plant Pathology Commons^™

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 …

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- …

Heterodimers As The Structural Unit Of The T=1 Capsid Of The Fungal Double-Stranded Rna Rosellinia Necatrix Quadrivirus 1, Daniel Luque, Carlos P. Mata, Fernando González-Camacho, José M. González, Josué Gómez-Blanco, Carlos Alfonso, Germán Rivas, Wendy M. Havens, Satoko Kanematsu, Nobuhiro Suzuki, Said A. Ghabrial, Benes L. Trus, José R Castón

Plant Pathology Faculty Publications

Most double-stranded RNA (dsRNA) viruses are transcribed and replicated in a specialized icosahedral capsid with a T=1 lattice consisting of 60 asymmetric capsid protein (CP) dimers. These capsids help to organize the viral genome and replicative complex(es). They also act as molecular sieves that isolate the virus genome from host defense mechanisms and allow the passage of nucleotides and viral transcripts. Rosellinia necatrix quadrivirus 1 (RnQV1), the type species of the family Quadriviridae, is a dsRNA fungal virus with a multipartite genome consisting of four monocistronic segments (segments 1 to 4). dsRNA-2 and dsRNA-4 encode two CPs (P2 and …

Building Viral Replication Organelles: Close Encounters Of The Membrane Types, Peter D. Nagy, Jeroen R. P. M. Strating, Frank J. M. Van Kuppeveld

Plant Pathology Faculty Publications

Positive-strand (+)RNA viruses are important and emerging pathogens of humans, animals, and plants. Upon infection, they induce the formation of specialized membranous replication organelles with unique lipid composition to facilitate robust virus replication. In this article, the authors discuss the proviral role of virus-induced membrane contact sites (vMCSs). The emerging picture is that vMCSs channel lipids to viral membranes and tune the lipid composition for optimal generation and functioning of replication organelles.

Two Complete Mitochondrial Genomes From Praticolella Mexicana Perez, 2011 (Polygyridae) And Gene Order Evolution In Helicoidea (Mollusca, Gastropoda), Russell L. Minton, Marco A. Martinez Cruz, Mark L. Farman, Kathryn E. Perez

Plant Pathology Faculty Publications

Helicoidea is a diverse group of land snails with a global distribution. While much is known regarding the relationships of helicoid taxa, comparatively little is known about the evolution of the mitochondrial genome in the superfamily. We sequenced two complete mitochondrial genomes from Praticolella mexicana Perez, 2011 representing the first such data from the helicoid family Polygyridae, and used them in an evolutionary analysis of mitogenomic gene order. We found the mitochondrial genome of P. mexicana to be 14,008 bp in size, possessing the typical 37 metazoan genes. Multiple alternate stop codons are used, as are incomplete stop codons. Mitogenome …

Enrichment Of Phosphatidylethanolamine In Viral Replication Compartments Via Co-Opting The Endosomal Rab5 Small Gtpase By A Positive-Strand Rna Virus, Kai Xu, Peter D. Nagy

Plant Pathology Faculty Publications

Positive-strand RNA viruses build extensive membranous replication compartments to support replication and protect the virus from antiviral responses by the host. These viruses require host factors and various lipids to form viral replication complexes (VRCs). The VRCs built by Tomato bushy stunt virus (TBSV) are enriched with phosphatidylethanolamine (PE) through a previously unknown pathway. To unravel the mechanism of PE enrichment within the TBSV replication compartment, in this paper, the authors demonstrate that TBSV co-opts the guanosine triphosphate (GTP)-bound active form of the endosomal Rab5 small GTPase via direct interaction with the viral replication protein. Deletion of Rab5 orthologs in …

Chromosome-End Knockoff Strategy To Reshape Alkaloid Profiles Of A Fungal Endophyte, Simona Florea, Timothy D. Phillips, Daniel G. Panaccione, Mark L. Farman, Christopher L. Schardl

Plant Pathology Faculty Publications

Molecular genetic techniques to precisely eliminate genes in asexual filamentous fungi require the introduction of a marker gene into the target genome. We developed a novel strategy to eliminate genes or gene clusters located in subterminal regions of chromosomes, and then eliminate the marker gene and vector backbone used in the transformation procedure. Because many toxin gene clusters are subterminal, this method is particularly suited to generating nontoxic fungal strains. We tested this technique on Epichloë coenophiala, a seed-transmissible symbiotic fungus (endophyte) of the important forage grass, tall fescue (Lolium arundinaceum). The endophyte is necessary for maximal …

Identification Of Diverse Mycoviruses Through Metatranscriptomics Characterization Of The Viromes Of Five Major Fungal Plant Pathogens, Shin-Yi Lee Marzano, Berlin D. Nelson, Olutoyosi Ajayi-Oyetunde, Carl A. Bradley, Teresa J. Hughes, Glen L. Hartman, Darin M. Eastburn, Leslie L. Domier

Plant Pathology Faculty Publications

Mycoviruses can have a marked effect on natural fungal communities and influence plant health and productivity. However, a comprehensive picture of mycoviral diversity is still lacking. To characterize the viromes of five widely dispersed plant-pathogenic fungi, Colletotrichum truncatum, Macrophomina phaseolina, Diaporthe longicolla, Rhizoctonia solani, and Sclerotinia sclerotiorum, a high-throughput sequencing-based metatranscriptomic approach was used to detect viral sequences. Total RNA and double-stranded RNA (dsRNA) from mycelia and RNA from samples enriched for virus particles were sequenced. Sequence data were assembled de novo, and contigs with predicted amino acid sequence similarities to viruses in the …

Genetic Engineering And Sustainable Crop Disease Management: Opportunities For Case-By-Case Decision-Making, Paul Vincelli

Plant Pathology Faculty Publications

Genetic engineering (GE) offers an expanding array of strategies for enhancing disease resistance of crop plants in sustainable ways, including the potential for reduced pesticide usage. Certain GE applications involve transgenesis, in some cases creating a metabolic pathway novel to the GE crop. In other cases, only cisgenessis is employed. In yet other cases, engineered genetic changes can be so minimal as to be indistinguishable from natural mutations. Thus, GE crops vary substantially and should be evaluated for risks, benefits, and social considerations on a case-by-case basis. Deployment of GE traits should be with an eye towards long-term sustainability; several …

Role Of Viral Rna And Co-Opted Cellular Escrt-I And Escrt-Iii Factors In Formation Of Tombusvirus Spherules Harboring The Tombusvirus Replicase, Nikolay Kovalev, Isabel Fernández De Castro Martín, Judit Pogany, Daniel Barajas, Kunj Bihari Pathak, Cristina Risco, Peter D. Nagy

Plant Pathology Faculty Publications

Plus-stranded RNA viruses induce membrane deformations in infected cells in order to build viral replication complexes (VRCs). Tomato bushy stunt virus (TBSV) co-opts cellular ESCRT (endosomal sorting complexes required for transport) proteins to induce the formation of vesicle (spherule)-like structures in the peroxisomal membrane with tight openings toward the cytosol. In this study, using a yeast (Saccharomyces cerevisiae) vps23Δ bro1Δ double-deletion mutant, we showed that the Vps23p ESCRT-I protein (Tsg101 in mammals) and Bro1p (ALIX) ESCRT-associated protein, both of which bind to the viral p33 replication protein, play partially complementary roles in TBSV replication in cells …

A Colletotrichum Graminicola Mutant Deficient In The Establishment Of Biotrophy Reveals Early Transcriptional Events In The Maize Anthracnose Disease Interaction, Maria F. Torres, Noushin Ghaffari, Ester A. S. Buiate, Neil Moore, Scott Schwartz, Charles D. Johnson, Lisa J. Vaillancourt

Plant Pathology Faculty Publications

Background: Colletotrichum graminicola is a hemibiotrophic fungal pathogen that causes maize anthracnose disease. It progresses through three recognizable phases of pathogenic development in planta: melanized appressoria on the host surface prior to penetration; biotrophy, characterized by intracellular colonization of living host cells; and necrotrophy, characterized by host cell death and symptom development. A “Mixed Effects” Generalized Linear Model (GLM) was developed and applied to an existing Illumina transcriptome dataset, substantially increasing the statistical power of the analysis of C. graminicola gene expression during infection and colonization. Additionally, the in planta transcriptome of the wild-type was compared with that of …

Cell-Free And Cell-Based Approaches To Explore The Roles Of Host Membranes And Lipids In The Formation Of Viral Replication Compartment Induced By Tombusviruses, Peter D. Nagy, Judit Pogany, Kai Xu

Plant Pathology Faculty Publications

Plant positive strand RNA viruses are intracellular infectious agents that take advantage of cellular lipids and membranes to support replication and protect viral RNA from degradation by host antiviral responses. In this review, we discuss how Tomato bushy stunt virus (TBSV) co-opts lipid transfer proteins and modulates lipid metabolism and transport to facilitate the assembly of the membrane-bound viral replicase complexes within intricate replication compartments. Identification and characterization of the proviral roles of specific lipids and proteins involved in lipid metabolism based on results from yeast (Saccharomyces cerevisiae) model host and cell-free approaches are discussed. The review also …

Viral Replication Protein Inhibits Cellular Cofilin Actin Depolymerization Factor To Regulate The Actin Network And Promote Viral Replicase Assembly, Muhammad Shah Nawaz-Ul-Rehman, K. Reddisiva Prasanth, Kai Xu, Zsuzsanna Sasvari, Nikolay Kovalev, Isabel Fernández De Castro Martín, Daniel Barajas, Cristina Risco, Peter D. Nagy

Plant Pathology Faculty Publications

RNA viruses exploit host cells by co-opting host factors and lipids and escaping host antiviral responses. Previous genome-wide screens with Tomato bushy stunt virus (TBSV) in the model host yeast have identified 18 cellular genes that are part of the actin network. In this paper, we show that the p33 viral replication factor interacts with the cellular cofilin (Cof1p), which is an actin depolymerization factor. Using temperature-sensitive (ts) Cof1p or actin (Act1p) mutants at a semi-permissive temperature, we find an increased level of TBSV RNA accumulation in yeast cells and elevated in vitro activity of the tombusvirus replicase. We show …

Genome Sequences Of Three Phytopathogenic Species Of The Magnaporthaceae Family Of Fungi, Laura H. Okagaki, Cristiano C. Nunes, Joshua Sailsbery, Brent Clay, Doug Brown, Titus John, Yeonyee Oh, Nelson Young, Michael Fitzgerald, Brian J. Haas, Qiandong Zeng, Sarah Young, Xian Adiconis, Lin Fan, Joshua Z. Levin, Thomas K. Mitchell, Patricia A. Okubara, Mark L. Farman, Linda M. Kohn, Bruce Birren, Li-Jun Ma, Ralph A. Dean

Plant Pathology Faculty Publications

Magnaporthaceae is a family of ascomycetes that includes three fungi of great economic importance: Magnaporthe oryzae, Gaeumannomyces graminis var. tritici, and Magnaporthe poae. These three fungi cause widespread disease and loss in cereal and grass crops, including rice blast disease (M. oryzae), take-all disease in wheat and other grasses (G. graminis), and summer patch disease in turf grasses (M. poae). Here, we present the finished genome sequence for M. oryzae and draft sequences for M. poae and G. graminis var. tritici. We used multiple technologies to sequence and annotate the …

Introduction To The Toxins Special Issue On Ergot Alkaloids, Christopher L. Schardl

Plant Pathology Faculty Publications

No abstract provided.

Characterization Of A Novel Megabirnavirus From Sclerotinia Sclerotiorum Reveals Horizontal Gene Transfer From Single-Stranded Rna Virus To Double-Stranded Rna Virus, Minghong Wang, Yong Wang, Xiangzhong Sun, Jiasen Cheng, Yanping Fu, Huiquan Liu, Daohong Jiang, Said A. Ghabrial, Jiatao Xie

Plant Pathology Faculty Publications

Mycoviruses have been detected in all major groups of filamentous fungi, and their study represents an important branch of virology. Here, we characterized a novel double-stranded RNA (dsRNA) mycovirus, Sclerotinia sclerotiorum megabirnavirus 1 (SsMBV1), in an apparently hypovirulent strain (SX466) of Sclerotinia sclerotiorum. Two similarly sized dsRNA segments (L1- and L2-dsRNA), the genome of SsMBV1, are packaged in rigid spherical particles purified from strain SX466. The full-length cDNA sequence of L1-dsRNA/SsMBV1 comprises two large open reading frames (ORF1 and ORF2), which encode a putative coat protein and an RNA-dependent RNA polymerase (RdRp), respectively. Phylogenetic analysis of the RdRp domain …

Activation Of Tomato Bushy Stunt Virus Rna-Dependent Rna Polymerase By Cellular Heat Shock Protein 70 Is Enhanced By Phospholipids In Vitro, Judit Pogany, Peter D. Nagy

Plant Pathology Faculty Publications

Similar to other positive-strand RNA viruses, tombusviruses are replicated by the membrane-bound viral replicase complex (VRC). The VRC consists of the p92 virus-coded RNA-dependent RNA polymerase (RdRp), the viral p33 RNA chaperone, and several co-opted host proteins. In order to become a functional RdRp after its translation, the p92 replication protein should be incorporated into the VRC, followed by its activation. We have previously shown in a cell-free yeast extract-based assay that the activation of the Tomato bushy stunt virus (TBSV) RdRp requires a soluble host factor(s). In this article, we identify the cellular heat shock protein 70 (Hsp70) as …

Viral Sensing Of The Subcellular Environment Regulates The Assembly Of New Viral Replicase Complexes During The Course Of Infection, Peter D. Nagy

Plant Pathology Faculty Publications

Replication of plus-stranded RNA [(+)RNA] viruses depends on the availability of coopted host proteins and lipids. But, how could viruses sense the accessibility of cellular resources? An emerging concept based on tombusviruses, small plant viruses, is that viruses might regulate viral replication at several steps depending on what cellular factors are available at a given time point. I discuss the role of phospholipids, sterols, and cellular WW domain proteins and eukaryotic elongation factor 1A (eEF1A) in control of activation of the viral RNA-dependent RNA polymerase (RdRp) and regulation of the assembly of viral replicase complexes (VRCs). These regulatory mechanisms might …

Signal Regulators Of Systemic Acquired Resistance, Qing-Ming Gao, Shifeng Zhu, Pradeep Kachroo, Aardra Kachroo

Plant Pathology Faculty Publications

Salicylic acid (SA) is an important phytohormone that plays a vital role in a number of physiological responses, including plant defense. The last two decades have witnessed a number of breakthroughs related to biosynthesis, transport, perception and signaling mediated by SA. These findings demonstrate that SA plays a crictical role in both local and systemic defense responses. Systemic acquired resistance (SAR) is one such SA-dependent response. SAR is a long distance signaling mechanism that provides broad spectrum and long-lasting resistance to secondary infections throughout the plant. This unique feature makes SAR a highly desirable trait in crop production. This review …

Genetics, Genomics And Evolution Of Ergot Alkaloid Diversity, Carolyn A. Young, Christopher L. Schardl, Daniel G. Panaccione, Simona Florea, Johanna E. Takach, Nikki D. Charlton, Neil Moore, Jennifer S. Webb, Jolanta Jaromczyk

Plant Pathology Faculty Publications

The ergot alkaloid biosynthesis system has become an excellent model to study evolutionary diversification of specialized (secondary) metabolites. This is a very diverse class of alkaloids with various neurotropic activities, produced by fungi in several orders of the phylum Ascomycota, including plant pathogens and protective plant symbionts in the family Clavicipitaceae. Results of comparative genomics and phylogenomic analyses reveal multiple examples of three evolutionary processes that have generated ergot-alkaloid diversity: gene gains, gene losses, and gene sequence changes that have led to altered substrates or product specificities of the enzymes that they encode (neofunctionalization). The chromosome ends appear to be …

Disparate Independent Genetic Events Disrupt The Secondary Metabolism Gene Pera In Certain Symbiotic Epichloë Species, Daniel Berry, Johanna E. Takach, Christopher L. Schardl, Nikki D. Charlton, Barry Scott, Carolyn A. Young

Plant Pathology Faculty Publications

Peramine is an insect-feeding deterrent produced by Epichloë species in symbiotic association with C₃ grasses. The perA gene responsible for peramine synthesis encodes a two-module nonribosomal peptide synthetase. Alleles of perA are found in most Epichloë species; however, peramine is not produced by many perA-containing Epichloë isolates. The genetic basis of these peramine-negative chemotypes is often unknown. Using PCR and DNA sequencing, we analyzed the perA genes from 72 Epichloë isolates and identified causative mutations of perA null alleles. We found nonfunctional perA-ΔR* alleles, which contain a transposon-associated deletion of the perA region encoding the C-terminal reductase …

In Vivo Localization Of Iris Yellow Spot Tospovirus (Bunyaviridae)-Encoded Proteins And Identification Of Interacting Regions Of Nucleocapsid And Movement Proteins, Diwaker Tripathi, Gaurav Raikhy, Michael M. Goodin, Ralf G. Dietzgen, Hanu R. Pappu

Plant Pathology Faculty Publications

BACKGROUND: Localization and interaction studies of viral proteins provide important information about their replication in their host plants. Tospoviruses (Family Bunyaviridae) are economically important viruses affecting numerous field and horticultural crops. Iris yellow spot virus (IYSV), one of the tospoviruses, has recently emerged as an important viral pathogen of Allium spp. in many parts of the world. We studied the in vivo localization and interaction patterns of the IYSV proteins in uninfected and infected Nicotiana benthamiana and identified the interacting partners.

PRINCIPAL FINDINGS: Bimolecular fluorescence complementation (BiFC) analysis demonstrated homotypic and heterotypic interactions between IYSV nucleocapsid …

The Proteasomal Rpn11 Metalloprotease Suppresses Tombusvirus Rna Recombination And Promotes Viral Replication Via Facilitating Assembly Of The Viral Replicase Complex, K. Reddisiva Prasanth, Daniel Barajas, Peter D. Nagy

Plant Pathology Faculty Publications

RNA viruses co-opt a large number of cellular proteins that affect virus replication and, in some cases, viral genetic recombination. RNA recombination helps viruses in an evolutionary arms race with the host's antiviral responses and adaptation of viruses to new hosts. Tombusviruses and a yeast model host are used to identify cellular factors affecting RNA virus replication and RNA recombination. In this study, we have examined the role of the conserved Rpn11p metalloprotease subunit of the proteasome, which couples deubiquitination and degradation of proteasome substrates, in tombusvirus replication and recombination in Saccharomyces cerevisiae and plants. Depletion or mutations of Rpn11p …

Coordinated Function Of Cellular Dead-Box Helicases In Suppression Of Viral Rna Recombination And Maintenance Of Viral Genome Integrity, Chingkai Chuang, K. Reddisiva Prasanth, Peter D. Nagy

Plant Pathology Faculty Publications

The intricate interactions between viruses and hosts include an evolutionary arms race and adaptation that is facilitated by the ability of RNA viruses to evolve rapidly due to high frequency mutations and genetic RNA recombination. In this paper, we show evidence that the co-opted cellular DDX3-like Ded1 DEAD-box helicase suppresses tombusviral RNA recombination in yeast model host, and the orthologous RH20 helicase functions in a similar way in plants. In vitro replication and recombination assays confirm the direct role of the ATPase function of Ded1p in suppression of viral recombination. We also present data supporting a role for Ded1 in …

Novel Mechanism Of Regulation Of Tomato Bushy Stunt Virus Replication By Cellular Ww-Domain Proteins, Daniel Barajas, Nikolay Kovalev, Jun Qin, Peter D. Nagy

Plant Pathology Faculty Publications

Replication of (+)RNA viruses depends on several co-opted host proteins but is also under the control of cell-intrinsic restriction factors (CIRFs). By using tombusviruses, small model viruses of plants, we dissect the mechanism of inhibition of viral replication by cellular WW-domain-containing proteins, which act as CIRFs. By using fusion proteins between the WW domain and the p33 replication protein, we show that the WW domain inhibits the ability of p33 to bind to the viral RNA and to other p33 and p92 replication proteins leading to inhibition of viral replication in yeast and in a cell extract. Overexpression of WW-domain …