Life Sciences Commons^™

Assembly-Hub Function Of Er-Localized Snare Proteins In Biogenesis Of Tombusvirus Replication Compartment, Zsuzsanna Sasvari, Nikolay Kovalev, Paulina Alatriste Gonzalez, Kai Xu, Peter D. Nagy

Plant Pathology Faculty Publications

Positive-strand RNA viruses assemble numerous membrane-bound viral replicase complexes within large replication compartments to support their replication in infected cells. Yet the detailed mechanism of how given subcellular compartments are subverted by viruses is incompletely understood. Although, Tomato bushy stunt virus (TBSV) uses peroxisomal membranes for replication, in this paper, we show evidence that the ER-resident SNARE (soluble NSF attachment protein receptor) proteins play critical roles in the formation of active replicase complexes in yeast model host and in plants. Depletion of the syntaxin 18-like Ufe1 and Use1, which are components of the ER SNARE complex in the ERAS (ER …

Co-Opting Atp-Generating Glycolytic Enzyme Pgk1 Phosphoglycerate Kinase Facilitates The Assembly Of Viral Replicase Complexes, K. Reddisiva Prasanth, Chingkai Chuang, Peter D. Nagy

Plant Pathology Faculty Publications

The intricate interactions between viruses and hosts include exploitation of host cells for viral replication by using many cellular resources, metabolites and energy. Tomato bushy stunt virus (TBSV), similar to other (+)RNA viruses, induces major changes in infected cells that lead to the formation of large replication compartments consisting of aggregated peroxisomal and ER membranes. Yet, it is not known how TBSV obtains the energy to fuel these energy-consuming processes. In the current work, the authors discovered that TBSV co-opts the glycolytic ATP-generating Pgk1 phosphoglycerate kinase to facilitate the assembly of new viral replicase complexes. The recruitment of Pgk1 into …

Phytoplasma Infection Of A Tropical Root Crop Triggers Bottom-Up Cascades By Favoring Generalist Over Specialist Herbivores, Kris A. G. Wyckhuys, Ignazio Graziosi, Dharani Dhar Burra, Abigail Jan Walter

Entomology Faculty Publications

Global interest on plant-microbe-insect interactions is rapidly growing, revealing the multiple ways in which microorganisms mediate plant-herbivore interactions. Phytopathogens regularly alter whole repertoires of plant phenotypic traits, and bring about shifts in key chemical or morphological characteristics of plant hosts. Pathogens can also cause cascading effects on higher trophic levels, and eventually shape entire plant-associated arthropod communities. We tested the hypothesis that a Candidatus Phytoplasma causing cassava witches’ broom (CWB) on cassava (Manihot esculenta Grantz) is altering species composition of invasive herbivores and their associated parasitic hymenopterans. We conducted observational studies in cassava fields in eastern Cambodia to assess …

Genome Sequence Variation In The Constricta Strain Dramatically Alters The Protein Interaction And Localization Map Of Potato Yellow Dwarf Virus, Chanyong Jang, Renyuan Wang, Joseph Wells, Fabian Leon, Mark Farman, John Hammond, Michael M. Goodin

Plant Pathology Faculty Publications

The genome sequence of the constricta strain of Potato yellow dwarf virus (CYDV) was determined to be 12 792 nt long and organized into seven ORFs with the gene order 3′-N-X-P-Y-M-G-L-5′, which encodes the nucleocapsid, phospho, movement, matrix, glyco, and RNA-dependent RNA polymerase proteins, respectively, except for X, which is of unknown function. Cloned ORFs for each gene, except L, were used to construct a protein interaction and localization map (PILM) for this virus, which shares greater than 80 % amino acid similarity in all ORFs except X and P with the sanguinolenta strain of this species (SYDV). Protein localization …

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- …

Aphid Performance Changes With Plant Defense Mediated By Cucumber Mosaic Virus Titer, Xiaobin Shi, Yang Gao, Shuo Yan, Xin Tang, Xuguo Zhou, Deyong Zhang, Yong Liu

Entomology Faculty Publications

Background: Cucumber mosaic virus (CMV) causes appreciable losses in vegetables, ornamentals and agricultural crops. The green peach aphid, Myzus persicae Sulzer (Aphididae) is one of the most efficient vectors for CMV. The transmission ecology of aphid-vectored CMV has been well investigated. However, the detailed description of the dynamic change in the plant-CMV-aphid interaction associated with plant defense and virus epidemics is not well known.

Results: In this report, we investigated the relationship of virus titer with plant defense of salicylic acid (SA) and jasmonic acid (JA) during the different infection time and their interaction with aphids in CMV-infected tobacco plants. …

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 …

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 …

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 …

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 …

Discovery Of Novel Dsrna Viral Sequences By In Silico Cloning And Implications For Viral Diversity, Host Range And Evolution, Huiquan Liu, Yanping Fu, Jiatao Xie, Jiasen Cheng, Said A. Ghabrial, Guoqing Li, Xianhong Yi, Daohong Jiang

Plant Pathology Faculty Publications

Genome sequence of viruses can contribute greatly to the study of viral evolution, diversity and the interaction between viruses and hosts. Traditional molecular cloning methods for obtaining RNA viral genomes are time-consuming and often difficult because many viruses occur in extremely low titers. DsRNA viruses in the families, Partitiviridae, Totiviridae, Endornaviridae, Chrysoviridae, and other related unclassified dsRNA viruses are generally associated with symptomless or persistent infections of their hosts. These characteristics indicate that samples or materials derived from eukaryotic organisms used to construct cDNA libraries and EST sequencing might carry these viruses, which were not easily detected by the researchers. …

The Combined Effect Of Environmental And Host Factors On The Emergence Of Viral Rna Recombinants, Hannah M. Jaag, Peter D. Nagy

Plant Pathology Faculty Publications

Viruses are masters of evolution due to high frequency mutations and genetic recombination. In spite of the significance of viral RNA recombination that promotes the emergence of drug-resistant virus strains, the role of host and environmental factors in RNA recombination is poorly understood. Here we report that the host Met22p/Hal2p bisphosphate-3'-nucleotidase regulates the frequency of viral RNA recombination and the efficiency of viral replication. Based on Tomato bushy stunt virus (TBSV) and yeast as a model host, we demonstrate that deletion of MET22 in yeast or knockdown of AHL, SAL1 and FRY1 nucleotidases/phosphatases in plants leads to increased TBSV recombination …

A Unique Role For The Host Escrt Proteins In Replication Of Tomato Bushy Stunt Virus, Daniel Barajas, Yi Jiang, Peter D. Nagy

Plant Pathology Faculty Publications

Plus-stranded RNA viruses replicate in infected cells by assembling viral replicase complexes consisting of viral- and host-coded proteins. Previous genome-wide screens with Tomato bushy stunt tombusvirus (TBSV) in a yeast model host revealed the involvement of seven ESCRT (endosomal sorting complexes required for transport) proteins in viral replication. In this paper, we show that the expression of dominant negative Vps23p, Vps24p, Snf7p, and Vps4p ESCRT factors inhibited virus replication in the plant host, suggesting that tombusviruses co-opt selected ESCRT proteins for the assembly of the viral replicase complex. We also show that TBSV p33 replication protein interacts with Vps23p ESCRT-I …