ABSTRACT: The changes of small RNA profile have been studied in tomato and wild tomato plants to understand the host reponse to the infection of a non-coding viral RNA infection.
ORGANISM(S): Solanum habrochaites Solanum lycopersicum Solanum lycopersicum x Solanum habrochaites
Project description:Plant virus infection involves the production of viral small RNAs (vsRNAs) with the potential to associate with distinct Argonaute (AGO)-containing silencing complexes and mediate diverse silencing effects on RNA and chromatin. We used multiplexed, high-throughput pyrosequencing to profile populations of vsRNAs from plants infected with viruses from different genera. Sense and antisense vsRNAs of 20 to 24 nucleotides (nts) spread throughout the entire viral genomes in an overlapping configuration; virtually all genomic nucleotide positions were represented in the dataset. We present evidence to suggest that every genomic position could be a putative cleavage site for vsRNA formation, although viral genomes contain specific regions that serve as preferential sources of vsRNA production. Hotspots for vsRNAs of 21-, 22-, and 24-nt usually coincide in the same genomic regions, indicating similar target affinities among Dicer-like (DCL) enzymes. In the light of our results, the overall contribution of perfectly base paired double-stranded RNA and imperfectly base paired structures within single-stranded RNA to vsRNA formation is discussed. Our census of vsRNAs extends the current view of the distribution and composition of vsRNAs in virus-infected plants, and contributes to define a more comprehensive scenario of vsRNA biogenesis and their regulatory functions in plants Raw data files are available on our FTP site: ftp://ftp.ncbi.nlm.nih.gov/pub/geosup/Series/GSE16996 10 samples examined: Arabidopsis plants infected with TRV, TuMV or CMV; Nicothiana benthamiana plants infected with CymRSV, PVX or PMMoV; Cucumis melo plants infected with MNSV, quimeric MNSV or WMV and Solanum lycopersicum plants infected with TYLCV.
Project description:Plant virus infection involves the production of viral small RNAs (vsRNAs) with the potential to associate with distinct Argonaute (AGO)-containing silencing complexes and mediate diverse silencing effects on RNA and chromatin. We used multiplexed, high-throughput pyrosequencing to profile populations of vsRNAs from plants infected with viruses from different genera. Sense and antisense vsRNAs of 20 to 24 nucleotides (nts) spread throughout the entire viral genomes in an overlapping configuration; virtually all genomic nucleotide positions were represented in the dataset. We present evidence to suggest that every genomic position could be a putative cleavage site for vsRNA formation, although viral genomes contain specific regions that serve as preferential sources of vsRNA production. Hotspots for vsRNAs of 21-, 22-, and 24-nt usually coincide in the same genomic regions, indicating similar target affinities among Dicer-like (DCL) enzymes. In the light of our results, the overall contribution of perfectly base paired double-stranded RNA and imperfectly base paired structures within single-stranded RNA to vsRNA formation is discussed. Our census of vsRNAs extends the current view of the distribution and composition of vsRNAs in virus-infected plants, and contributes to define a more comprehensive scenario of vsRNA biogenesis and their regulatory functions in plants Raw data files are available on our FTP site: ftp://ftp.ncbi.nlm.nih.gov/pub/geosup/Series/GSE16996
Project description:Pepino Mosaic Virus (PepMV) consists a major pathogenic threat in the greenhouses worldwide and has a devasting impact on tomato global production. PepMV belongs to the Potexvirus genus of the Flexiviridae family. PepMV has a viral RNA genome of approximately 6400 nucleotides long that contains five open reading frames (ORFs) and 4 major genotypes have been characterized. TomCr3, an indigenous virulent PepMV strain derived from the Chilean (CH2) genotype, was isolated in Crete, Greece and was used for the mechanical infection of Belladonna F1 hybrid tomato seedlings. Here, we present the results of a deep RNA-sequencing (RNA-seq) analysis performed to characterize the dynamic expression profile of tomato genes upon PepMV infection, including tomato transcription factors.
Project description:We performed threefold evolution experiment with tobacco etch potyvirus isolate At17b (TEV-At17b) in five different ecotypes of Arabidopsis thaliana L. (Di-2, Ei-2, Ler-0, St-0, and Wt-1,), that are heterogeneous in their susceptibility to TEV-At17b infection. After the evolution phase, (i) we characterized the fitness and virulence of the evolved lineages across all host ecotypes, (ii) the molecular changes fixed in the viral genomes. Next, we analyzed the transcriptoma of the plants using Agilent Microarray tecnology (i)plants infected with local adapted viral lineage, (ii)plants infected with evolved virus vs. ancestal virus, (iii) virus evolved in new host and infecting its original host, (iv) transcriptoma of most specialized and most generalized viruses infecting all five ecotypes.
Project description:Southern tomato virus (STV) often infects healthy tomato plants (Solanum lycopersicum). In this study, we compared STV-free and STV-infected cultivar M82 plants to determine the effect of STV infection on the host plant. STV-free plants exhibited a short and bushy phenotype, whereas STV-infected plants exhibited increased height. STV-infected plants produced more fruit than STV-free plants, and the germination rate of seeds from STV-infected plants was higher than that of seeds from STV-free plants. This phenotypic difference was also observed in progeny plants (siblings) derived from a single STV-infected plant in which the transmission rate of STV to progeny plants via the seeds was approximately 86%. These results suggest that the interaction between STV and host plants is mutualistic. Transcriptome analyses revealed that STV infection affected gene expressions in host plants, notably evidenced by down-regulation of genes involved in ethylene biosynthesis and signaling. STV-infected tomato plants thus might be artificially selected due to their superior traits as a crop.
Project description:Heldt2012 - Influenza Virus Replication
The model describes the life cycle of influenza A virus in a mammalian cell including the following steps: attachment of parental virions to the cell membrane, receptor-mediated endocytosis, fusion of the virus envelope with the endosomal membrane, nuclear import of vRNPs, viral transcription and replication, translation of the structural viral proteins, nuclear export of progeny vRNPs and budding of new virions. It also explicitly accounts for the stabilization of cRNA by viral polymerases and NP and the inhibition of vRNP activity by M1 protein binding. In short, the model focuses on the molecular mechanism that controls viral transcription and replication.
This model is described in the article:
Modeling the intracellular dynamics of influenza virus replication to understand the control of viral RNA synthesis.
Heldt FS, Frensing T, Reichl U.
J Virol.
Abstract:
Influenza viruses transcribe and replicate their negative-sense RNA genome inside the nucleus of host cells via three viral RNA species. In the course of an infection, these RNAs show distinct dynamics, suggesting that differential regulation takes place. To investigate this regulation in a systematic way, we developed a mathematical model of influenza virus infection at the level of a single mammalian cell. It accounts for key steps of the viral life cycle, from virus entry to progeny virion release, while focusing in particular on the molecular mechanisms that control viral transcription and replication. We therefore explicitly consider the nuclear export of viral genome copies (vRNPs) and a recent hypothesis proposing that replicative intermediates (cRNA) are stabilized by the viral polymerase complex and the nucleoprotein (NP). Together, both mechanisms allow the model to capture a variety of published data sets at an unprecedented level of detail. Our findings provide theoretical support for an early regulation of replication by cRNA stabilization. However, they also suggest that the matrix protein 1 (M1) controls viral RNA levels in the late phase of infection as part of its role during the nuclear export of viral genome copies. Moreover, simulations show an accumulation of viral proteins and RNA toward the end of infection, indicating that transport processes or budding limits virion release. Thus, our mathematical model provides an ideal platform for a systematic and quantitative evaluation of influenza virus replication and its complex regulation.
With the current parameter set, the model reproduces an infection at a multiplicity of infection (MOI) of 10. Figure 2A of the paper is reproduced here, with parameters kDegRnp and kSynP changed to zeros.
Initial conditions and parameter changes that were used to obtain specific figures in the article can be found in Table A2.
The model has the correct value for kAttLo as 4.55e-04. The value of this parameter mentioned as 4.55e-02 in Table 1 of the paper is incorrect. This is checked with the author.
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Project description:Viruses are obligate intracellular pathogens that depend on host factors to complete their infection cycle. Very little is known of which plant factors are required for successful Tomato spotted wilt orthotospovirus (TSWV) infection. The viral ribonucleoprotein (RNP) fraction from TSWV infected Nicotiana benthamiana plants was purified and its protein composition was analysed by proteomics by mass spectrometry to identify host proteins that co-purify with viral RNPs. Related, we expressed a TSWV replicon system in a non-host system, Bakers’ yeast (Saccharomyces cerevisiae), and purified as well the RNP fraction from yeast. Comparative proteomics was used to find common enriched proteins observed in both yeast and plant RNP fractions.
Project description:The plant response may be triggered by various factors, including pathogens, non-pathogenic microbes, and natural or synthetic molecules, such as salicylic acid (SA), benzo(1,2,3)-Thiadiazole-7-Carbothioic Acid S-Methyl Ester (BTH) that are considered as plant resistance inducers. Resistance inducers mobilize the plant for the synthesis of defense compounds, but they are not directly toxic for the plant. The BTH is an analogue of SA, a molecule naturally synthesized in the plant during systemic acquired resistance (SAR). In this study, we hypothesized that challenging the plant with resistance inducer causes an increase in the level of proteins associated with defence response to external stimuli with primary metabolism and that the action of the choline derivative of the BTH (in the form of the ionic liquid) during induction of resistance in tomato plants is mediated by to some extent similar signaling pathways as it is in the case of unmodified BTH compound. Therefore, this study aimed to identify global proteome changes occurring in tomato plants exposed to resistance inducers as well as to identify common pathways associated with the plant's defense response to (+)ssRNA viruses induced upon both, viral infection and prior resistance inducer treatment. The effect of ionic liquids on changes in plant proteome is not described in the literature. The ionic character of compounds offers a great advantage of using them as the plant resistance inducer. The high chemical and thermal stability, as well as low volatility, guarantees safe application in fields. For that reason, comparing the action of the resistance inducer in the form of an ionic liquid with the core compound (BTH) will help to elucidate the mode of action of ionic liquid derivatives in plant resistance induction. To this end, two RNA-type viruses from different families were tested: tomato mosaic virus (ToMV, Virgaviridae) and potato virus Y (PVY, Potyviridae). The most affected processes presented in the results were: photosynthesis, regulation of oxidative stress, metabolism of glutathione and chitin, cell wall reorganization. The increased impact on the regulation of primary metabolism in inducer-treated plants (both for BTH and cholinium ionic liquid derivative). The response to ToMV and PVY was more intense when infected plants were pre-treated with inducers. The increased abundances of defense priming proteins with changes in cell wall organization may block virus transport from infected spots to other tissue of the host plant so that the losses caused by the disease will be lower.
Project description:Purpose: To understand the molecular mechanisms involved in disease development during plant-nematode interactions. Methods: We have taken a comprehensive transcriptomic approach to investigate the expression of both tomato and RKN genes in tomato roots at five infection time points from susceptible plants (PR: Pusa Ruby) and two infection time points from resistant plants (M36: Transgenic MM line), grown under soil conditions. Results: Differentially expressed genes during susceptible (1827 tomato, 462 RKN) and resistance (25 tomato, 160 RKN) interactions were identified and a set of genes were validated by qRT-PCR. Conclusion: Our findings, for the first time, provide insights into the transcriptome dynamics of both tomato and RKN during susceptible and resistance interactions and reveal involvement of a complex network of biosynthetic pathways during disease development.