Mixed Infections of Plant Viruses in Crops: Solo vs. Group Game

Plant diseases are responsible for considerable economic losses in agriculture worldwide. Recent surveys and metagenomics approaches reveal a higher than expected incidence of complex diseases, like those caused by mixed viral infections. Particularly, frequent cases of mixed infections are co-infections or superinfections of plant viruses belonging to different genera in the families Potyviridae (Ipomovirus or Potyvirus) and Closteroviridae (Crinivirus). The outcome of such multiple infections could modify viral traits, such as host range, titer, tissue and cell tropisms, and even vector preference and transmission rates. Therefore, we believe that understanding the virus–virus, virus–host, and virus–vector interactions would be crucial for developing effective control measures. Since there is still limited knowledge about the molecular mechanisms underlying the different interactions, and how they might contribute to specific diseases in mixed infection, we are analyzing ipomovirus–crinivirus and potyvirus–crinivirus pathosystems, to better understand single and mixed infections in selected susceptible hosts (Cucurbitaceae and Convolvulaceae plants), also incorporating in the study the interactions with insect vectors (whiteflies and aphids). Among other strategies, we are engineering new biotechnological tools, to explore the molecular biology and transmission mechanisms of several viruses implicated in complex diseases, and we are also addressing the possibility to produce virus-like particles (VLPs) through transient expression of the CP of different viruses in Nicotiana benthamiana plants, with the aim to study requirements for virion formation and determinants of transmission. Work supported by project AGL2016-75529-R and grant “Severo-Ochoa” SEV-2015-0533.

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When Viruses Play Team Sports: Mixed Infections in Plants

Phytopathology ◽

10.1094/phyto-07-19-0250-fi ◽

2020 ◽

Vol 110 (1) ◽

pp. 29-48 ◽

Cited By ~ 20

Author(s):

Ana Beatriz Moreno ◽

Juan José López-Moya

Keyword(s):

Viral Infections ◽

Team Sports ◽

Plant Viruses ◽

Multiple Infections ◽

Mixed Infections ◽

Transmission Mechanisms ◽

Single Host ◽

Complex Events ◽

Experimental Approaches ◽

The Impact

The pathological importance of mixed viral infections in plants might be underestimated except for a few well-characterized synergistic combinations in certain crops. Considering that the host ranges of many viruses often overlap and that most plant species can be infected by several unrelated viruses, it is not surprising to find more than one virus simultaneously in the same plant. Furthermore, dispersal of the majority of plant viruses relies on efficient transmission mechanisms mediated by vector organisms, mainly but not exclusively insects, which can contribute to the occurrence of multiple infections in the same plant. Recent work using different experimental approaches has shown that mixed viral infections can be remarkably frequent, up to the point that they could be considered the rule more than the exception. The purpose of this review is to describe the impact of multiple infections not only on the participating viruses themselves but also on their vectors and on the common host. From this standpoint, mixed infections arise as complex events that involve several cross-interacting players, and they consequently require a more general perspective than the analysis of single-virus/single-host approaches for a full understanding of their relevance.

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Co-circulation of Chikungunya and Dengue viruses in Dengue endemic region of New Delhi, India during 2016

Epidemiology and Infection ◽

10.1017/s0950268818001590 ◽

2018 ◽

Vol 146 (13) ◽

pp. 1642-1653 ◽

Cited By ~ 2

Author(s):

M. Hisamuddin ◽

A. Tazeen ◽

M. Abdullah ◽

M. Islamuddin ◽

N. Parveen ◽

...

Keyword(s):

Viral Infections ◽

Purifying Selection ◽

Control Measures ◽

Effective Control ◽

New Delhi ◽

Emerging Pathogens ◽

Endemic Region ◽

High Entropy ◽

Genotype Iii ◽

Two Samples

AbstractCo-circulation of Chikungunya and Dengue viral infections (CHIKV and DENV) have been reported mainly due to transmission by commonAedesvector. The purpose of the study was to identify and characterise the circulating strains of CHIKV and DENV in DENV endemic region of New Delhi during 2016. CHIKV and DENV were identified in the blood samples (n= 130) collected from suspected patients by RT-PCR. CHIKV was identified in 26 of 65 samples (40%). Similarly, DENV was detected in 48 of 120 samples (40%). Co-infection with both the viruses was identified in five (9%) of the samples. Interestingly, concurrent infection with DENV, CHIKV andPlasmodium vivaxwas detected in two samples. CHIKV strains (n= 11) belonged to the ECSA genotype whereas DENV-3 sequences (n= eight) clustered in Genotype III by phylogenetic analysis. Selection pressure of E1 protein of CHIKV and CprM protein of DENV-3 revealed purifying selection with four and two positive sites, respectively. Four amino acids of the CHIKV were positively selected and had high entropy suggesting probable variations. Co-circulation of both viruses in DENV endemic regions warrants effective monitoring of these emerging pathogens via comprehensive surveillance for implementation of effective control measures.

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Draft Genome Sequence and Transcriptional Analysis of Rosellinia necatrix Infected with a Virulent Mycovirus

Phytopathology ◽

10.1094/phyto-11-17-0365-r ◽

2018 ◽

Vol 108 (10) ◽

pp. 1206-1211 ◽

Cited By ~ 4

Author(s):

Takeo Shimizu ◽

Satoko Kanematsu ◽

Hajime Yaegashi

Keyword(s):

Genome Sequence ◽

Molecular Mechanisms ◽

Plant Cell Wall ◽

Draft Genome ◽

Transcriptional Analysis ◽

Draft Genome Sequence ◽

Effective Control ◽

Economic Losses ◽

Rosellinia Necatrix ◽

Cell Wall Degrading Enzymes

Understanding the molecular mechanisms of pathogenesis is useful in developing effective control methods for fungal diseases. The white root rot fungus Rosellinia necatrix is a soilborne pathogen that causes serious economic losses in various crops, including fruit trees, worldwide. Here, using next-generation sequencing techniques, we first produced a 44-Mb draft genome sequence of R. necatrix strain W97, an isolate from Japan, in which 12,444 protein-coding genes were predicted. To survey differentially expressed genes (DEGs) associated with the pathogenesis of the fungus, the hypovirulent W97 strain infected with Rosellinia necatrix megabirnavirus 1 (RnMBV1) was used for a comprehensive transcriptome analysis. In total, 545 and 615 genes are up- and down-regulated, respectively, in R. necatrix infected with RnMBV1. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses of the DEGs suggested that primary and secondary metabolism would be greatly disturbed in R. necatrix infected with RnMBV1. The genes encoding transcriptional regulators, plant cell wall-degrading enzymes, and toxin production, such as cytochalasin E, were also found in the DEGs. The genetic resources provided in this study will accelerate the discovery of genes associated with pathogenesis and other biological characteristics of R. necatrix, thus contributing to disease control.

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Gene-for-gene interactions are required for disease resistance mediated by virus transgene

Plant Protection Science ◽

10.17221/10349-pps ◽

2002 ◽

Vol 38 (SI 1 - 6th Conf EFPP 2002) ◽

pp. 177-179

Author(s):

M. Ravelonandro

Keyword(s):

Disease Resistance ◽

Rna Interference ◽

Molecular Mechanisms ◽

Plant Viruses ◽

Economic Losses ◽

Gene Interactions ◽

Severe Damage ◽

Breeding Programs ◽

Pathogen Derived Resistance ◽

Potential Use

Plant viruses cause severe damage and significant economic losses to agriculture. Control of virus usually consist of the elimination of virus vectors (insects, nematodes, fungi, etc), improvement of the sanitary status of the propagation material, the use of resistance sources in breeding programs. The application of the pathogen-derived resistance strategy has opened new avenues to protect plants against viruses. Two molecular mechanisms seem to underlie the engineered protection, the virus transgene-derived protein and the transgene-RNA interference. A few examples that support the efficiencies of these two molecular mechanisms are reviewed here and discussed in light of the potential use of virusresistant transgenic plants in agriculture.

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The viral etiology of tomato yellow leaf curl disease – a review

Plant Protection Science ◽

10.17221/26/2009-pps ◽

2009 ◽

Vol 45 (No. 3) ◽

pp. 81-97 ◽

Cited By ~ 32

Author(s):

E. Glick ◽

Y. Levy ◽

Y. Gafni

Keyword(s):

Molecular Mechanisms ◽

Tomato Yellow Leaf ◽

Plant Diseases ◽

Effective Control ◽

Insect Vector ◽

Yellow Leaf ◽

Severe Problem ◽

South Central ◽

Leaf Curl Disease ◽

Leaf Curl

Tomato yellow leaf curl disease (TYLCD) is one of the most devastating plant diseases in the world. As a result of its continuing rapid spread, it now afflicts more than 30 tomato growing countries in the Mediterranean basin, southern Asia, Africa, and South, Central and North America. The disease is caused by a group of viral species of the genus Begomovirus, family Geminiviridae (geminiviruses), referred to as Tomato yellow leaf curl virus (TYLCV). These are transmitted by an insect vector, the whitefly Bemisia tabaci, classified in the family Aleyrodidae. The genome of TYLCV generally consists of a single circular single-stranded (ss) DNA molecule, with only one exception in which two components were identified. It encodes six open reading frames, only one of which codes for the coat protein (CP) that represents a building block of the viral particle. TYLCV, like all other members of the Geminiviridae, has geminate particles, apparently consisting of two incomplete T = 1 icosahedra joined together to produce a structure with 22 pentameric capsomers and 110 identical CP subunits. Close to 50 years of intensive research into TYLCV epidemics has been conducted to find solutions to the severe problem caused by this virus. To date, breeding for resistance appears to be the best approach to controlling this disease, although only partially resistant varieties are commercially available. Since the virus consists of a ssDNA that replicates in the host-cell nucleus, the molecular mechanisms involved in its nuclear import have been the focus of our studies in recent years and results, as well as prospects, are discussed in this review. In addition, we describe our recent finding of a suppressor of gene silencing encoded by one of the TYLCV-Isr genes. This paper provides an overview of the most outstanding achievements in TYLCV research that may lead to more effective control strategies.

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Novel Cytopathological Structures Induced by Mixed Infection of Unrelated Plant Viruses

Phytopathology ◽

10.1094/phyto.2004.94.1.111 ◽

2004 ◽

Vol 94 (1) ◽

pp. 111-119 ◽

Cited By ~ 11

Author(s):

E. M. Martin ◽

J. D. Cho ◽

J. S. Kim ◽

S. C. Goeke ◽

K. S. Kim ◽

...

Keyword(s):

Mosaic Virus ◽

Mixed Infection ◽

Viral Infections ◽

Soybean Mosaic Virus ◽

Plant Viruses ◽

Mixed Infections ◽

Cowpea Mosaic Virus ◽

Viral Interactions ◽

Sunn Hemp ◽

Blackeye Cowpea Mosaic Virus

When two unrelated plant viruses infect a plant simultaneously, synergistic viral interactions often occur resulting in devastating diseases. This study was initiated to examine ultrastructural virus-virus interactions of mixed viral infections. Mixed infections were induced using potyviruses and viruses from other plant virus families. Novel ultrastructural paracrystalline arrays composed of co-infecting viruses, referred to as mixed virus particle aggregates (MVPAs), were noted in the majority of the mixed infections studied. When the flexuous rod-shaped potyvirus particles involved in MVPAs were sectioned transversely, specific geometrical patterns were noted within some doubly infected cells. Although similar geometrical patterns were associated with MVPAs of various virus combinations, unique characteristics within patterns were consistent in each mixed infection virus pair. Centrally located virus particles within some MVPAs appeared swollen (Southern bean mosaic virus mixed with Blackeye cowpea mosaic virus, Cucumber mosaic virus mixed with Blackeye cowpea mosaic virus, and Sunn hemp mosaic virus mixed with Soybean mosaic virus). This ultrastructural study complements molecular studies of mixed infections of plant viruses by adding the additional dimension of visualizing the interactions between the coinfecting viruses.

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Impact of viral features, host jumps and phylogeography on the rapid evolution of Aleutian mink disease virus (AMDV)

Scientific Reports ◽

10.1038/s41598-021-96025-z ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Giovanni Franzo ◽

Matteo Legnardi ◽

Laura Grassi ◽

Giorgia Dotto ◽

Michele Drigo ◽

...

Keyword(s):

Disease Virus ◽

Rapid Evolution ◽

Global Scale ◽

Control Measures ◽

Viral Population ◽

Effective Control ◽

Economic Losses ◽

Aleutian Mink Disease Virus ◽

Different Populations

AbstractAleutian mink disease virus (AMDV) is one the most relevant pathogens of domestic mink, where it can cause significant economic losses, and wild species, which are considered a threat to mink farms. Despite their relevance, many aspects of the origin, evolution, and geographic and host spreading patterns of AMDV have never been investigated on a global scale using a comprehensive biostatistical approach. The present study, benefitting from a large dataset of sequences collected worldwide and several phylodynamic-based approaches, demonstrates the ancient origin of AMDV and its broad, unconstrained circulation from the initial intercontinental spread to the massive among-country circulation, especially within Europe, combined with local persistence and evolution. Clear expansion of the viral population size occurred over time until more effective control measures started to be applied. The role of frequent changes in epidemiological niches, including different hosts, in driving the high nucleotide and amino acid evolutionary rates was also explored by comparing the strengths of selective pressures acting on different populations. The obtained results suggest that the viral passage among locations and between wild and domesticated animals poses a double threat to farm profitability and animal welfare and health, which is particularly relevant for endangered species. Therefore, further efforts must be made to limit viral circulation and to refine our knowledge of factors enhancing AMDV spread, particularly at the wild-domestic interface.

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Optimal Pest Control Strategies with Cost-effectiveness Analysis

The Scientific World JOURNAL ◽

10.1155/2021/6630193 ◽

2021 ◽

Vol 2021 ◽

pp. 1-17

Author(s):

Ihza Rizkia Fitri ◽

Farida Hanum ◽

Ali Kusnanto ◽

Toni Bakhtiar

Keyword(s):

Cost Effectiveness ◽

Plant Density ◽

Control Strategies ◽

Rapid Development ◽

Cost Effectiveness Analysis ◽

Plant Diseases ◽

Control Measures ◽

Economic Losses ◽

Healthy Plant ◽

Effectiveness Analysis

Pest and plant diseases cause damages and economic losses, threatening food security and ecosystem services. Thus, proper pest management is indispensable to mitigate the risk of losses. The risk of environmental hazards induced by toxic chemicals alongside the rapid development of chemical resistance by insects entails more resilient, sustainable, and ecologically sound approaches to chemical methods of control. This study evaluates the application of three dynamical measures of controls, namely, green insecticide, mating disruption, and the removal of infected plants, in controlling pest insects. A model was built to describe the interaction between plants and insects as well as the circulation of the pathogen. Optimal control measures are sought in such a way they maximize the healthy plant density jointly with the pests’ density under the lowest possible control efforts. Our simulation study shows that all strategies succeed in controlling the insects. However, a cost-effectiveness analysis suggests that a strategy with two measures of green insecticide and plant removal is the most cost-effective, followed by one which applies all control measures. The best strategy projects the decrease of potential loss from 65.36% to 6.12%.

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The E3 Ubiquitin Ligase TRIM25 Inhibits Tembusu Virus Replication in vitro

Frontiers in Veterinary Science ◽

10.3389/fvets.2021.722113 ◽

2021 ◽

Vol 8 ◽

Author(s):

Han Kaikai ◽

Dongmin Zhao ◽

Yuzhuo Liu ◽

Qingtao Liu ◽

Xinmei Huang ◽

...

Keyword(s):

Ubiquitin Ligase ◽

Egg Production ◽

Molecular Mechanisms ◽

E3 Ubiquitin Ligase ◽

Control Measures ◽

Neurological Dysfunction ◽

Health Concern ◽

Economic Losses ◽

Tembusu Virus

Duck Tembusu virus (DTMUV) is a newly emerging pathogenic flavivirus that has caused significant economic losses to the duck industry in China since 2010 due to egg production losses and neurological dysfunction. DTMUV is a public health concern because the infection spreads rapidly among birds. Retinoic acid-inducible gene-I (RIG-I)serves as an innate immune sensor and plays a key role in host antiviral defenses. Tripartite motif-containing protein 25 (TRIM25), an E3 ubiquitin ligase, is pivotal for RIG-I ubiquitination and activation. In addition, TRIM25 acts as an interferon-stimulated gene and mediates the antiviral activity. However, the effect of duck TRIM25 on DTMUV has not been assessed. Herein, we reportthe antiviral function of TRIM25 against DTMUV. First, we constructed the pcDNA3.1-c-myc-duTRIM25 plasmid. TRIM25 has a 2052 bp open reading frame that encodes a predicted 684 amino acid protein consisting of a RING finger domain, a B-box domain, a coiled-coil domain, and a PRY/SPRY domain. The protein sequence identity with chicken, mouse, and human TRIM25 is 69.7, 47.8, and 48.3%, respectively. TRIM25 was upregulated in BHK-21 cells, duck embryo fibroblasts, and 293T cellsupon DTMUV infection. The expression of viral RNA and proteins was significantly lower in cells over expressing TRIM25 than in control cells. Furthermore, siRNA-mediated silencing of TRIM25 increased the production of viral progeny. These results help elucidate the molecular mechanisms underlying the host response to DTMUV infection and suggest potential control measures for DTMUV outbreaks.

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Prevalence, co-infection and seasonality of fecal enteropathogens from diarrheic cats in the Republic of Korea (2016–2019): a retrospective study

BMC Veterinary Research ◽

10.1186/s12917-021-03075-6 ◽

2021 ◽

Vol 17 (1) ◽

Author(s):

Ye-In Oh ◽

Kyoung-Won Seo ◽

Do-Hyung Kim ◽

Doo-Sung Cheon

Keyword(s):

Bacterial Infections ◽

Viral Infections ◽

Clinical Symptoms ◽

Age Distribution ◽

Multiple Infections ◽

Mixed Infections ◽

Tritrichomonas Foetus ◽

Infectious Diarrhea ◽

Feline Parvovirus ◽

The Republic

Abstract Background Diarrhea is one of the most common clinical symptoms in cats and can be caused by infectious pathogens and investigation of the prevalence, co-infection and seasonality of enteropathogens are not well-established in diarrheic cats. Results Fecal samples of 1620 diarrheic cats were collected and enteropathogens were detected using real-time PCR. We retrospectively investigated the clinical features, total/seasonal prevalence, and infection patterns of enteropathogens. The positive infection rate was 82.59%. Bacterial, viral, and protozoal infections accounted for 49.3, 37.57, and 13.13% of cases, respectively. Feline enteric coronavirus (FECV) was the most common pathogen (29.37%), followed by Clostridium (C.) perfringens, Campylobacter (C.) coli, feline parvovirus, and Tritrichomonas foetus. The seasonality of enteropathogens was observed with peaks as follows: bacterial infections peaked in October, viral infections peaked in November, and protozoal infections peaked in August. Viral and protozoal infections showed differences in prevalence according to patient age. In the infection patterns, the ratios of single infections, mixed infections, and co-infections were 35.72, 9.87, and 54.41%, respectively. FECV was predominant in single infections. The most common patterns of multiple infections were C. perfringens and C. coli in mixed infections and C. perfringens and FECV in co-infections. Conclusions Infection patterns differed according to the enteropathogen species, seasonality, and age distribution in cats. The results of this study might be helpful to understand in clinical characteristics of feline infectious diarrhea. In addition, continued monitoring of feline enteropathogens is required.

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