scholarly journals Superinfection by PHYVV Alters the Recovery Process in PepGMV-Infected Pepper Plants

Viruses ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 286 ◽  
Author(s):  
Myriam G. Rodríguez-Gandarilla ◽  
Edgar A. Rodríguez-Negrete ◽  
Rafael F. Rivera-Bustamante
Keyword(s):  
Plant Pathogens ◽  
Recovery Process ◽  
Pepper Plant ◽  
Bipartite Begomovirus ◽  
Suppressor Activity ◽  
Host Interactions ◽  
Chromatin Activation ◽  
Reporter Systems ◽  
Silencing Suppression ◽  
Silencing Pathways

Geminiviruses are important plant pathogens that affect crops around the world. In some geminivirus–host interactions, infected plants show recovery, a phenomenon characterized by symptom disappearance in newly emerging leaves. In pepper–Pepper golden mosaic virus (PepGMV) interaction, the host recovery process involves a silencing mechanism that includes both post-transcriptional (PTGS) and transcriptional (TGS) gene silencing pathways. Under field conditions, PepGMV is frequently found in mixed infections with Pepper huasteco yellow vein virus (PHYVV), another bipartite begomovirus. Mixed infected plants generally show a synergetic phenomenon and do not present recovery. Little is known about the molecular mechanism of this interaction. In the present study, we explored the effect of superinfection by PHYVV on a PepGMV-infected pepper plant showing recovery. Superinfection with PHYVV led to (a) the appearance of severe symptoms, (b) an increase of the levels of PepGMV DNA accumulation, (c) a decrease of the relative methylation levels of PepGMV DNA, and (d) an increase of chromatin activation marks present in viral minichromosomes. Finally, using heterologous expression and silencing suppression reporter systems, we found that PHYVV REn presents TGS silencing suppressor activity, whereas similar experiments suggest that Rep might be involved in suppressing PTGS.

scholarly journals Tracing the Lineage of Two Traits Associated with the Coat Protein of the Tombusviridae: Silencing Suppression and HR Elicitation in Nicotiana Species

Viruses ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 588 ◽  
Author(s):  
Mustafa Adhab ◽  
Carlos Angel ◽  
Andres Rodriguez ◽  
Mohammad Fereidouni ◽  
Lóránt Király ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Structural Changes ◽  
Coat Proteins ◽  
Silencing Suppressor ◽  
Suppressor Activity ◽  
Nicotiana Species ◽  
Pathogen Effector ◽  
The Family ◽  
Silencing Suppression ◽  
Insight Into

In this paper we have characterized the lineage of two traits associated with the coat proteins (CPs) of the tombusvirids: Silencing suppression and HR elicitation in Nicotiana species. We considered that the tombusvirid CPs might collectively be considered an effector, with the CP of each CP-encoding species comprising a structural variant within the family. Thus, a phylogenetic analysis of the CP could provide insight into the evolution of a pathogen effector. The phylogeny of the CP of tombusvirids indicated that CP representatives of the family could be divided into four clades. In two separate clades the CP triggered a hypersensitive response (HR) in Nicotiana species of section Alatae but did not have silencing suppressor activity. In a third clade the CP had a silencing suppressor activity but did not have the capacity to trigger HR in Nicotiana species. In the fourth clade, the CP did not carry either function. Our analysis illustrates how structural changes that likely occurred in the CP effector of progenitors of the current genera led to either silencing suppressor activity, HR elicitation in select Nicotiana species, or neither trait.

scholarly journals Genetic Analyses of the FRNK Motif Function of Turnip mosaic virus Uncover Multiple and Potentially Interactive Pathways of Cross-Protection

2014 ◽  
Vol 27 (9) ◽  
pp. 944-955 ◽  
Author(s):  
Yi-Jung Kung ◽  
Pin-Chun Lin ◽  
Shyi-Dong Yeh ◽  
Syuan-Fei Hong ◽  
Nam-Hai Chua ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Mosaic Virus ◽  
Rna Silencing ◽  
Turnip Mosaic Virus ◽  
Cross Protection ◽  
Mild Strain ◽  
Silencing Suppression ◽  
Helper Component Proteinase ◽  
Silencing Pathways ◽  
Protection Against Infection

Cross-protection triggered by a mild strain of virus acts as a prophylaxis to prevent subsequent infections by related viruses in plants; however, the underling mechanisms are not fully understood. Through mutagenesis, we isolated a mutant strain of Turnip mosaic virus (TuMV), named Tu-GK, that contains an Arg182Lys substitution in helper component-proteinase (HC-ProK) that confers complete cross-protection against infection by a severe strain of TuMV in Nicotiana benthamiana, Arabidopsis thaliana Col-0, and the Arabidopsis dcl2-4/dcl4-1 double mutant defective in DICER-like ribonuclease (DCL)2/DCL4-mediated silencing. Our analyses showed that HC-ProK loses the ability to interfere with microRNA pathways, although it retains a partial capability for RNA silencing suppression triggered by DCL. We further showed that Tu-GK infection triggers strong salicylic acid (SA)-dependent and SA-independent innate immunity responses. Our data suggest that DCL2/4-dependent and –independent RNA silencing pathways are involved, and may crosstalk with basal innate immunity pathways, in host defense and in cross-protection.

scholarly journals Translocation of Tomato Bushy Stunt Virus P19 Protein into the Nucleus by ALY Proteins Compromises Its Silencing Suppressor Activity

2006 ◽  
Vol 80 (18) ◽  
pp. 9064-9072 ◽  
Author(s):  
Tomas Canto ◽  
Joachim F. Uhrig ◽  
Maud Swanson ◽  
Kathryn M. Wright ◽  
Stuart A. MacFarlane
Keyword(s):  
Rna Silencing ◽  
Tomato Bushy Stunt Virus ◽  
Bimolecular Fluorescence Complementation ◽  
Rna Recognition Motif ◽  
Rna Recognition ◽  
Long Distance ◽  
Suppressor Activity ◽  
Recognition Motif ◽  
Silencing Suppression ◽  
Suppressor Of Rna Silencing

ABSTRACT The P19 protein of Tomato bushy stunt virus is a potent suppressor of RNA silencing and, depending on the host species, is required for short- and long-distance virus movement and symptom production. P19 interacts with plant ALY proteins and relocalizes a subset of these proteins from the nucleus to the cytoplasm. Here we showed that coexpression by agroinfiltration in Nicotiana benthamiana of P19 and the subset of ALY proteins that are not relocalized from the nucleus interfered with the ability of P19 to suppress RNA silencing. We demonstrated that this interference correlates with the relocation of P19 from the cytoplasm into the nucleus, and by constructing and analyzing chimeric ALY genes, we showed that the C-terminal part of the central, RNA recognition motif of ALY is responsible for interaction with P19, relocalization or nonrelocalization of ALY, and inhibition of silencing suppression by P19. We studied the interaction of ALY and P19 by using the technique of bimolecular fluorescence complementation to show that these proteins associate physically in the nucleus but not detectably in the cytoplasm, and we present a model to explain the dynamics of this interaction.

scholarly journals Root-Knot Nematode Parasitism Suppresses Host RNA Silencing

2017 ◽  
Vol 30 (4) ◽  
pp. 295-300 ◽  
Author(s):  
E. Walsh ◽  
J. M. Elmore ◽  
C. G. Taylor
Keyword(s):  
Rna Silencing ◽  
Plant Pathogens ◽  
Giant Cells ◽  
Root Knot Nematode ◽  
Root Cells ◽  
Feeding Site ◽  
Nematode Parasitism ◽  
Silencing Pathways ◽  
Plant Pathosystems ◽  
Viral Suppressors

Root-knot nematodes damage crops around the world by developing complex feeding sites from normal root cells of their hosts. The ability to initiate and maintain this feeding site (composed of individual “giant cells”) is essential to their parasitism process. RNA silencing pathways in plants serve a diverse set of functions, from directing growth and development to defending against invading pathogens. Influencing a host’s RNA silencing pathways as a pathogenicity strategy has been well-documented for viral plant pathogens, but recently, it has become clear that silencing pathways also play an important role in other plant pathosystems. To determine if RNA silencing pathways play a role in nematode parasitism, we tested the susceptibility of plants that express a viral suppressor of RNA silencing. We observed an increase in susceptibility to nematode parasitism in plants expressing viral suppressors of RNA silencing. Results from studies utilizing a silenced reporter gene suggest that active suppression of RNA silencing pathways may be occurring during nematode parasitism. With these studies, we provide further evidence to the growing body of plant-biotic interaction research that suppression of RNA silencing is important in the successful interaction between a plant-parasitic animal and its host.

scholarly journals Uncovering the Role of Metabolism in Oomycete–Host Interactions Using Genome-Scale Metabolic Models

2021 ◽  
Vol 12 ◽  
Author(s):  
Sander Y. A. Rodenburg ◽  
Michael F. Seidl ◽  
Dick de Ridder ◽  
Francine Govers
Keyword(s):  
Systems Biology ◽  
Plant Pathogens ◽  
Building Blocks ◽  
Metabolic Model ◽  
Microbial Pathogens ◽  
Biochemical Reactions ◽  
Host Interactions ◽  
A Genome ◽  
The Many ◽  
Genome Scale

Metabolism is the set of biochemical reactions of an organism that enables it to assimilate nutrients from its environment and to generate building blocks for growth and proliferation. It forms a complex network that is intertwined with the many molecular and cellular processes that take place within cells. Systems biology aims to capture the complexity of cells, organisms, or communities by reconstructing models based on information gathered by high-throughput analyses (omics data) and prior knowledge. One type of model is a genome-scale metabolic model (GEM) that allows studying the distributions of metabolic fluxes, i.e., the “mass-flow” through the network of biochemical reactions. GEMs are nowadays widely applied and have been reconstructed for various microbial pathogens, either in a free-living state or in interaction with their hosts, with the aim to gain insight into mechanisms of pathogenicity. In this review, we first introduce the principles of systems biology and GEMs. We then describe how metabolic modeling can contribute to unraveling microbial pathogenesis and host–pathogen interactions, with a specific focus on oomycete plant pathogens and in particular Phytophthora infestans. Subsequently, we review achievements obtained so far and identify and discuss potential pitfalls of current models. Finally, we propose a workflow for reconstructing high-quality GEMs and elaborate on the resources needed to advance a system biology approach aimed at untangling the intimate interactions between plants and pathogens.

scholarly journals The bunyavirus nonstructural protein NSs suppresses plant immunity to facilitate its own transmission by improving vector insect performance

2018 ◽  
Author(s):  
Xiujuan Wu ◽  
Shuang Xu ◽  
Pingzhi Zhao ◽  
Xiangmei Yao ◽  
Yanwei Sun ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Plant Pathogens ◽  
Molecular Mechanisms ◽  
Nonstructural Protein ◽  
Pathogen Transmission ◽  
Terpene Synthase ◽  
Silencing Suppressor ◽  
Suppressor Activity ◽  
Arthropod Vectors ◽  
Vector Behavior

AbstractPandemics of vector-borne human and plant pathogens often rely on the behaviors of their arthropod vectors. Arboviruses, including many bunyaviruses, manipulate vector behavior to accelerate their own transmission to vertebrates, birds, insects, and plants. However, the molecular mechanism underlying this manipulation remains elusive. Here, we report that the non-structural protein NSs of orthotospovirus (order Bunyavirales, family Tospoviridae), is a key viral factor that indirectly modifies vector preference and increases vector performance. NSs suppresses the biosynthesis of volatile monoterpenes, which serve as repellents of the vector Western flower thrips (WFT, Frankliniella occidentalis) instead of using its known silencing suppressor activity. NSs directly interacts with and relocalizes the jasmonate (JA) signaling master regulator MYC2 and its two close homologs, MYC3 and MYC4, to disable JA-mediated activation of terpene synthase genes. The dysfunction of the MYCs subsequently attenuates host defenses, increases the attraction of thrips, and improves thrips fitness. These findings elucidate the molecular mechanism through which a bunyavirus manipulates vector behaviors and therefore facilitate disease transmission. Our results provide important insights into the molecular mechanisms by which tospoviruses NSs counteracts host immunity for pathogen transmission.Author summaryMost bunyaviruses are transmitted by insect vectors, and some of them can modify the behaviors of their arthropod vectors to increase transmission to mammals, birds, and plants. NSs is a non-structural bunyavirus protein with multiple functions that acts as an avirulence determinant and silencing suppressor. In this study, we identified a new function of NSs as a manipulator of vector behavior, independent of its silencing suppressor activity. NSs manipulates jasmonate-mediated immunity against thrips by directly interacting with several homologs of MYC transcription factors, the core regulators of the jasmonate-signaling pathway. This hijacking by NSs enhances thrips preference and performance. Many human- and animal-infecting members of the Bunyaviridales also encode NSs and could manipulate vector behavior to accelerate their own transmission. Therefore, our data support the hypothesis that the NSs protein may play conserved roles among various members of the Bunyaviridales in the modification of vector feeding behavior that evolved as a mechanism to enhance virus transmission.

scholarly journals RNA4-encoded p31 of beet necrotic yellow vein virus is involved in efficient vector transmission, symptom severity and silencing suppression in roots

2007 ◽  
Vol 88 (5) ◽  
pp. 1611-1619 ◽  
Author(s):  
Muhammad Danial Rahim ◽  
Ida Bagus Andika ◽  
Chenggui Han ◽  
Hideki Kondo ◽  
Tetsuo Tamada
Keyword(s):  
Sugar Beet ◽  
Rna Silencing ◽  
Viral Rna ◽  
Yellow Vein ◽  
Symptom Expression ◽  
Suppressor Activity ◽  
Vector Transmission ◽  
Efficient Vector ◽  
Silencing Suppression ◽  
Rna Accumulation

RNA3 and RNA4 of beet necrotic yellow vein virus (BNYVV) are not essential for virus multiplication, but are associated with vector-mediated infection and disease development in sugar beet roots. Here, a unique role for RNA4 in virus transmission, virulence and RNA silencing suppression was demonstrated. Mutagenic analysis revealed that the RNA4-encoded p31 open reading frame (ORF) was involved in efficient vector transmission and slight enhancement of symptom expression in some Beta species. No effects of RNA4 on virus accumulation in infected tissue were observed. Furthermore, the p31 ORF was involved in the induction of severe symptoms by BNYVV in Nicotiana benthamiana plants without affecting viral RNA accumulation. In contrast, RNA3-encoded p25, previously identified as a major contributor to symptom induction in sugar beet, had no such effect on N. benthamiana. In two different silencing suppression assays, neither p31 nor p25 was able to suppress RNA silencing in leaves, but the presence of p31 enhanced a silencing suppressor activity in roots without alteration in viral RNA accumulation. Thus, BNYVV p31 plays a multifunctional role in efficient vector transmission, enhanced symptom expression and root-specific silencing suppression.

scholarly journals Characterization of Pathogenicity-Associated V2 Protein of Tobacco Curly Shoot Virus

2021 ◽  
Vol 22 (2) ◽  
pp. 923
Author(s):  
Mingjun Li ◽  
Changchang Li ◽  
Kairong Jiang ◽  
Ke Li ◽  
Junlei Zhang ◽  
...  
Keyword(s):  
Rna Silencing ◽  
Viral Infections ◽  
Infectious Clone ◽  
Potato Virus X ◽  
Transient Expression Assay ◽  
Systemic Necrosis ◽  
Suppressor Activity ◽  
Amino Acid Region ◽  
Tobacco Curly Shoot Virus ◽  
Silencing Suppression

V2 proteins encoded by some whitefly-transmitted geminiviruses were reported to be functionally important proteins. However, the functions of the V2 protein of tobacco curly shoot virus (TbCSV), a monopartite begomovirus that causes leaf curl disease on tomato and tobacco in China, remains to be characterized. In our report, an Agrobacterium infiltration-mediated transient expression assay indicated that TbCSV V2 can suppress local and systemic RNA silencing and the deletion analyses demonstrated that the amino acid region 1–92 of V2, including the five predicted α-helices, are required for local RNA silencing suppression. Site-directed substitutions showed that the conserved basic and ring-structured amino acids in TbCSV V2 are critical for its suppressor activity. Potato virus X-mediated heteroexpression of TbCSV V2 in Nicotiana benthamiana induced hypersensitive response-like (HR-like) cell death and systemic necrosis in a manner independent of V2′s suppressor activity. Furthermore, TbCSV infectious clone mutant with untranslated V2 protein (TbCSV∆V2) could not induce visual symptoms, and coinfection with betasatellite (TbCSB) could obviously elevate the viral accumulation and symptom development. Interestingly, symptom recovery occurred at 15 days postinoculation (dpi) and onward in TbCSV∆V2/TbCSB-inoculated plants. The presented work contributes to understanding the RNA silencing suppression activity of TbCSV V2 and extends our knowledge of the multifunctional role of begomovirus-encoded V2 proteins during viral infections.

scholarly journals Phevamine A, a small molecule that suppresses plant immune responses

2018 ◽  
Vol 115 (41) ◽  
pp. E9514-E9522 ◽  
Author(s):  
Erinn M. O’Neill ◽  
Tatiana S. Mucyn ◽  
Jon B. Patteson ◽  
Omri M. Finkel ◽  
Eui-Hwan Chung ◽  
...  
Keyword(s):  
Immune Responses ◽  
Small Molecules ◽  
Pseudomonas Syringae ◽  
Small Molecule ◽  
Virulence Factor ◽  
Plant Pathogens ◽  
Crop Damage ◽  
Host Interactions ◽  
Potentiation Effect ◽  
Reactive Oxygen Species Burst

Bacterial plant pathogens cause significant crop damage worldwide. They invade plant cells by producing a variety of virulence factors, including small-molecule toxins and phytohormone mimics. Virulence of the model pathogen Pseudomonas syringae pv. tomato DC3000 (Pto) is regulated in part by the sigma factor HrpL. Our study of the HrpL regulon identified an uncharacterized, three-gene operon in Pto that is controlled by HrpL and related to the Erwinia hrp-associated systemic virulence (hsv) operon. Here, we demonstrate that the hsv operon contributes to the virulence of Pto on Arabidopsis thaliana and suppresses bacteria-induced immune responses. We show that the hsv-encoded enzymes in Pto synthesize a small molecule, phevamine A. This molecule consists of l-phenylalanine, l-valine, and a modified spermidine, and is different from known small molecules produced by phytopathogens. We show that phevamine A suppresses a potentiation effect of spermidine and l-arginine on the reactive oxygen species burst generated upon recognition of bacterial flagellin. The hsv operon is found in the genomes of divergent bacterial genera, including ∼37% of P. syringae genomes, suggesting that phevamine A is a widely distributed virulence factor in phytopathogens. Our work identifies a small-molecule virulence factor and reveals a mechanism by which bacterial pathogens overcome plant defense. This work highlights the power of omics approaches in identifying important small molecules in bacteria–host interactions.

scholarly journals Comparative Genomics, Pangenome, and Phylogenomic Analyses of Brenneria spp., and Delineation of Brenneria izadpanahii sp. nov.

2020 ◽  
pp. PHYTO-04-20-012
Author(s):  
Meysam Bakhshi ganje ◽  
John Mackay ◽  
Mogens Nicolaisen ◽  
Masoud Shams-Bakhsh
Keyword(s):  
Comparative Genomics ◽  
Type Iii Secretion ◽  
Woody Plants ◽  
Plant Pathogens ◽  
Plant Cell Wall ◽  
Functional Genomic ◽  
Cell Wall Degrading Enzymes ◽  
Host Interactions ◽  
The Core ◽  
Phylogenomic Analyses

Brenneria species are bacterial plant pathogens mainly affecting woody plants. Association of all members with devastating disorders (e.g., acute oak decline in Iran and United Kingdom) are due to adaptation and pathogenic behavior in response to host and environmental factors. Some species, including B. goodwinii, B. salicis, and B. nigrifluens, also show endophytic residence. Here we show that all species including novel Brenneria sp. are closely related. Gene-based and genome/pangenome-based phylogeny divide the genus into two distinct lineages, Brenneria clades A and B. The two clades were functionally distinct and were consistent with their common and special potential activities as determined via annotation of functional domains. Pangenome analysis demonstrated that the core pathogenicity factors were highly conserved, an hrp gene cluster encoding a type III secretion system was found in all species except B. corticis. An extensive repertoire of candidate virulence factors was identified. Comparative genomics indicated a repertoire of plant cell wall degrading enzymes, metabolites/antibiotics, and numerous prophages providing new insights into Brenneria−host interactions and appropriate targets for further characterization. This work not only documented the genetic differentiation of Brenneria species but also delineates a more functionally driven understanding of Brenneria by comparison with relevant Pectobacteriaceae thereby substantially enriching the extent of information available for functional genomic investigations.

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