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Ali M, Polgári D, Sepsi A, Kontra L, Dalmadi Á, Havelda Z, Sági L, Kis A. Correction: Rapid and cost-effective molecular karyotyping in wheat, barley, and their crossprogeny by chromosome-specific multiplex PCR. Plant Methods 2024; 20:55. [PMID: 38641614 PMCID: PMC11031907 DOI: 10.1186/s13007-024-01179-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/21/2024]
Affiliation(s)
- Mohammad Ali
- , Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences,, 2100, Gödöllő, Hungary
- , Doctoral School of Plant Sciences, Hungarian University of Agriculture and Life Sciences,, 2100, Gödöllő, Hungary
| | - Dávid Polgári
- , Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences,, 2100, Gödöllő, Hungary
- , Centre for Agricultural Research, Hungarian Research Network,, 2462, Martonvásár, Hungary
- , Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Centre for Agricultural Research, , 2462, Martonvásár, Hungary
| | - Adél Sepsi
- , Centre for Agricultural Research, Hungarian Research Network,, 2462, Martonvásár, Hungary
| | - Levente Kontra
- , Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences,, 2100, Gödöllő, Hungary
- , Institute of Experimental Medicine, Bioinformatics Core Facility, Hungarian Research Network,, 1083, Budapest, Hungary
| | - Ágnes Dalmadi
- , Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences,, 2100, Gödöllő, Hungary
- , Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Hungarian University of Agriculture and Life Sciences,, 2100, Gödöllő, Hungary
| | - Zoltán Havelda
- , Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences,, 2100, Gödöllő, Hungary
- , Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Hungarian University of Agriculture and Life Sciences,, 2100, Gödöllő, Hungary
| | - László Sági
- , Centre for Agricultural Research, Hungarian Research Network,, 2462, Martonvásár, Hungary.
- , Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Centre for Agricultural Research, , 2462, Martonvásár, Hungary.
| | - András Kis
- , Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences,, 2100, Gödöllő, Hungary
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Miloro F, Kis A, Havelda Z, Dalmadi Á. Barley AGO4 proteins show overlapping functionality with distinct small RNA-binding properties in heterologous complementation. Plant Cell Rep 2024; 43:96. [PMID: 38480545 PMCID: PMC10937801 DOI: 10.1007/s00299-024-03177-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 02/15/2024] [Indexed: 03/17/2024]
Abstract
KEY MESSAGE Barley AGO4 proteins complement expressional changes of epigenetically regulated genes in Arabidopsis ago4-3 mutant and show a distinct affinity for the 5' terminal nucleotide of small RNAs, demonstrating functional conservation and divergence. The function of Argonaute 4 (AGO4) in Arabidopsis thaliana has been extensively characterized; however, its role in monocots, which have large genomes abundantly supplemented with transposable elements (TEs), remains elusive. The study of barley AGO4 proteins can provide insights into the conserved aspects of RNA-directed DNA methylation (RdDM) and could also have further applications in the field of epigenetics or crop improvement. Bioinformatic analysis of RNA sequencing data identified two active AGO4 genes in barley, HvAGO4a and HvAGO4b. These genes function similar to AtAGO4 in an Arabidopsis heterologous complementation system, primarily binding to 24-nucleotide long small RNAs (sRNAs) and triggering methylation at specific target loci. Like AtAGO4, HvAGO4B exhibits a preference for binding sRNAs with 5' adenine residue, while also accepting 5' guanine, uracil, and cytosine residues. In contrast, HvAGO4A selectively binds only sRNAs with a 5' adenine residue. The diverse binding capacity of barley AGO4 proteins is reflected in TE-derived sRNAs and in their varying abundance. Both barley AGO4 proteins effectively restore the levels of extrachromosomal DNA and transcript abundancy of the heat-activated ONSEN retrotransposon to those observed in wild-type Arabidopsis plants. Our study provides insight into the distinct binding specificities and involvement in TE regulation of barley AGO4 proteins in Arabidopsis by heterologous complementation.
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Affiliation(s)
- Fabio Miloro
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Gödöllő, Hungary
| | - András Kis
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary
| | - Zoltán Havelda
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Gödöllő, Hungary
| | - Ágnes Dalmadi
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary.
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Gödöllő, Hungary.
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Ali M, Polgári D, Sepsi A, Kontra L, Dalmadi Á, Havelda Z, Sági L, Kis A. Rapid and cost-effective molecular karyotyping in wheat, barley, and their cross-progeny by chromosome-specific multiplex PCR. Plant Methods 2024; 20:37. [PMID: 38444026 PMCID: PMC10913579 DOI: 10.1186/s13007-024-01162-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 02/20/2024] [Indexed: 03/07/2024]
Abstract
BACKGROUND Interspecific hybridisation is a powerful tool for increasing genetic diversity in plant breeding programmes. Hexaploid wheat (Triticum aestivum, 2n = 42) × barley (Hordeum vulgare, 2n = 14) intergeneric hybrids can contribute to the transfer of agronomically useful traits by creating chromosome addition or translocation lines as well as full hybrids. Information on the karyotype of hybrid progenies possessing various combinations of wheat and barley chromosomes is thus essential for the subsequent breeding steps. Since the standard technique of chromosome in situ hybridisation is labour-intensive and requires specific skills. a routine, cost-efficient, and technically less demanding approach is beneficial both for research and breeding. RESULTS We developed a Multiplex Polymerase Chain Reaction (MPCR) method to identify individual wheat and barley chromosomes. Chromosome-specific primer pairs were designed based on the whole genome sequences of 'Chinese Spring' wheat and 'Golden Promise' barley as reference cultivars. A pool of potential primers was generated by applying a 20-nucleotide sliding window with consecutive one-nucleotide shifts on the reference genomes. After filtering for optimal primer properties and defined amplicon sizes to produce an ordered ladder-like pattern, the primer pool was manually curated and sorted into four MPCR primer sets for the wheat A, B, and D sub-genomes, and for the barley genome. The designed MPCR primer sets showed high chromosome specificity in silico for the genome sequences of all 18 wheat and barley cultivars tested. The MPCR primers proved experimentally also chromosome-specific for the reference cultivars as well as for 13 additional wheat and four barley genotypes. Analyses of 16 wheat × barley F1 hybrid plants demonstrated that the MPCR primer sets enable the fast and one-step detection of all wheat and barley chromosomes. Finally, the established genotyping system was fully corroborated with the standard genomic in situ hybridisation (GISH) technique. CONCLUSIONS Wheat and barley chromosome-specific MPCR offers a fast, labour-friendly, and versatile alternative to molecular cytogenetic detection of individual chromosomes. This method is also suitable for the high-throughput analysis of distinct (sub)genomes, and, in contrast to GISH, can be performed with any tissue type. The designed primer sets proved to be highly chromosome-specific over a wide range of wheat and barley genotypes as well as in wheat × barley hybrids. The described primer design strategy can be extended to many species with precise genome sequence information.
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Affiliation(s)
- Mohammad Ali
- Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Gödöllő, 2100, Hungary
- Doctoral School of Plant Sciences, Hungarian University of Agriculture and Life Sciences, Gödöllő, 2100, Hungary
| | - Dávid Polgári
- Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Gödöllő, 2100, Hungary
- Centre for Agricultural Research, Hungarian Research Network, Martonvásár, 2462, Hungary
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Centre for Agricultural Research, Martonvásár, 2462, Hungary
| | - Adél Sepsi
- Centre for Agricultural Research, Hungarian Research Network, Martonvásár, 2462, Hungary
| | - Levente Kontra
- Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Gödöllő, 2100, Hungary
- Institute of Experimental Medicine, Bioinformatics Core Facility, Hungarian Research Network, Budapest, 1083, Hungary
| | - Ágnes Dalmadi
- Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Gödöllő, 2100, Hungary
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Hungarian University of Agriculture and Life Sciences, Gödöllő, 2100, Hungary
| | - Zoltán Havelda
- Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Gödöllő, 2100, Hungary
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Hungarian University of Agriculture and Life Sciences, Gödöllő, 2100, Hungary
| | - László Sági
- Centre for Agricultural Research, Hungarian Research Network, Martonvásár, 2462, Hungary.
- Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Centre for Agricultural Research, Martonvásár, 2462, Hungary.
| | - András Kis
- Institute of Genetics and Biotechnology, Hungarian University of Agriculture and Life Sciences, Gödöllő, 2100, Hungary.
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Kis A, Polgári D, Dalmadi Á, Ahmad I, Rakszegi M, Sági L, Csorba T, Havelda Z. Targeted mutations in the GW2.1 gene modulate grain traits and induce yield loss in barley. Plant Sci 2024; 340:111968. [PMID: 38157889 DOI: 10.1016/j.plantsci.2023.111968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 12/14/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024]
Abstract
Grain Width and Weight 2 (GW2) is an E3-ubiquitin ligase-encoding gene that negatively regulates the size and weight of the grain in cereal species. Therefore, disabling GW2 gene activity was suggested for enhancing crop productivity. We show here that CRISPR/Cas-mediated mutagenesis of the barley GW2.1 homologue results in the development of elongated grains and increased protein content. At the same time, GW2.1 loss of function induces a significant grain yield deficit caused by reduced spike numbers and low grain setting. We also show that the converse effect caused by GW2.1 absence on crop yield and protein content is largely independent of cultivation conditions. These findings indicate that the barley GW2.1 gene is necessary for the optimization between yield and grain traits. Altogether, our data show that the loss of GW2.1 gene activity in barley is associated with pleiotropic effects negatively affecting the development of generative organs and consequently the grain production. Our findings contribute to the better understanding of grain development and the utilisation of GW2.1 control in quantitative and qualitative genetic improvement of barley.
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Affiliation(s)
- András Kis
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary
| | - Dávid Polgári
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary; Agricultural Institute, Centre for Agricultural Research, Martonvásár, Hungary; Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Hungary
| | - Ágnes Dalmadi
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary; Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Hungary
| | - Imtiaz Ahmad
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary
| | - Marianna Rakszegi
- Agricultural Institute, Centre for Agricultural Research, Martonvásár, Hungary
| | - László Sági
- Agricultural Institute, Centre for Agricultural Research, Martonvásár, Hungary; Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Hungary
| | - Tibor Csorba
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary
| | - Zoltán Havelda
- Hungarian University of Agriculture and Life Sciences (MATE), Institute of Genetics and Biotechnology, Gödöllő, Hungary; Agribiotechnology and Precision Breeding for Food Security National Laboratory, Plant Biotechnology Section, Hungary.
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Dalmadi Á, Miloro F, Bálint J, Várallyay É, Havelda Z. Controlled RISC loading efficiency of miR168 defined by miRNA duplex structure adjusts ARGONAUTE1 homeostasis. Nucleic Acids Res 2021; 49:12912-12928. [PMID: 34850097 PMCID: PMC8682782 DOI: 10.1093/nar/gkab1138] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 10/25/2021] [Accepted: 11/16/2021] [Indexed: 11/12/2022] Open
Abstract
Micro RNAs (miRNAs) are processed from precursor RNA molecules with precisely defined secondary stem-loop structures. ARGONAUTE1 (AGO1) is the main executor component of miRNA pathway and its expression is controlled via the auto-regulatory feedback loop activity of miR168 in plants. Previously we have shown that AGO1 loading of miR168 is strongly restricted leading to abundant cytoplasmic accumulation of AGO-unbound miR168. Here, we report, that intrinsic RNA secondary structure of MIR168a precursor not only defines the processing of miR168, but also precisely adjusts AGO1 loading efficiency determining the biologically active subset of miR168 pool. Our results show, that modification of miRNA duplex structure of MIR168a precursor fragment or expression from artificial precursors can alter the finely adjusted loading efficiency of miR168. In dcl1-9 mutant where, except for miR168, production of most miRNAs is severely reduced this mechanism ensures the elimination of unloaded AGO1 proteins via enhanced AGO1 loading of miR168. Based on this data, we propose a new competitive loading mechanism model for miR168 action: the miR168 surplus functions as a molecular buffer for controlled AGO1 loading continuously adjusting the amount of AGO1 protein in accordance with the changing size of the cellular miRNA pool.
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Affiliation(s)
- Ágnes Dalmadi
- Hungarian University of Agriculture and Life Sciences, Institute of Genetics and Biotechnology, Páter Károly Street 1, Gödöllő 2100, Hungary
| | - Fabio Miloro
- Hungarian University of Agriculture and Life Sciences, Institute of Genetics and Biotechnology, Páter Károly Street 1, Gödöllő 2100, Hungary
| | - Jeannette Bálint
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi Albert Street 4, Gödöllő 2100, Hungary
| | - Éva Várallyay
- Hungarian University of Agriculture and Life Sciences, Institute of Plant Protection, Ménesi Street 44, Budapest 1118, Hungary
| | - Zoltán Havelda
- To whom correspondence should be addressed. Tel: +36 28430494;
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Dalmadi Á, Gyula P, Bálint J, Szittya G, Havelda Z. AGO-unbound cytosolic pool of mature miRNAs in plant cells reveals a novel regulatory step at AGO1 loading. Nucleic Acids Res 2019; 47:9803-9817. [PMID: 31392979 PMCID: PMC6765109 DOI: 10.1093/nar/gkz690] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/09/2019] [Accepted: 07/29/2019] [Indexed: 01/23/2023] Open
Abstract
RNA interference (RNAi) is mediated by small, 20-24-nt-long, non-coding regulatory (s)RNAs such as micro (mi) and small interfering (si) RNAs via the action of ARGONAUTE (AGO) proteins. High-throughput sequencing of size-separated sRNA pools of plant crude extracts revealed that the majority of the canonical miRNAs were associated with high molecular weight RNA-induced silencing complexes co-migrating with AGO1 (HMW RISC). In contrast, the majority of 24-nt-long siRNAs were found in association with low molecular weight complexes co-migrating with AGO4 (LMW RISC). Intriguingly, we identified a large set of cytoplasmic sRNAs, including mature miRNA sequences, in the low molecular size range corresponding to protein-unbound sRNAs. By comparing the RISC-loaded and protein-unbound pools of miRNAs, we identified miRNAs with highly different loading efficiencies. Expression of selected miRNAs in transient and transgenic systems validated their altered loading abilities implying that this process is controlled by information associated with the diverse miRNA precursors. We also showed that the availability of AGO proteins is a limiting factor determining the loading efficiency of miRNAs. Our data reveal the existence of a regulatory checkpoint determining the RISC-loading efficiencies of various miRNAs by sorting only a subset of the produced miRNAs into the biologically active RISCs.
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Affiliation(s)
- Ágnes Dalmadi
- Department of Plant Biotechnology, Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Szent-Györgyi Albert Str. 4., Gödöllő 2100, Hungary
| | - Péter Gyula
- Department of Plant Biotechnology, Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Szent-Györgyi Albert Str. 4., Gödöllő 2100, Hungary
| | - Jeannette Bálint
- Department of Plant Biotechnology, Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Szent-Györgyi Albert Str. 4., Gödöllő 2100, Hungary
| | - György Szittya
- Department of Plant Biotechnology, Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Szent-Györgyi Albert Str. 4., Gödöllő 2100, Hungary
| | - Zoltán Havelda
- Department of Plant Biotechnology, Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Szent-Györgyi Albert Str. 4., Gödöllő 2100, Hungary
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Kis A, Hamar É, Tholt G, Bán R, Havelda Z. Creating highly efficient resistance against wheat dwarf virus in barley by employing CRISPR/Cas9 system. Plant Biotechnol J 2019; 17:1004-1006. [PMID: 30633425 PMCID: PMC6523583 DOI: 10.1111/pbi.13077] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 12/04/2018] [Accepted: 12/31/2018] [Indexed: 05/18/2023]
Affiliation(s)
- András Kis
- National Agricultural Research and Innovation CentreAgricultural Biotechnology InstituteGödöllőHungary
| | - Éva Hamar
- National Agricultural Research and Innovation CentreAgricultural Biotechnology InstituteGödöllőHungary
- Georgikon FacultyFestetics Doctoral SchoolUniversity of PannoniaKeszthelyHungary
| | - Gergely Tholt
- Plant Protection InstituteCentre for Agricultural ResearchHungarian Academy of SciencesBudapestHungary
- Department of Systematic Zoology and EcologyFaculty of ScienceInstitute of BiologyEötvös Loránd UniversityBudapestHungary
| | - Rita Bán
- Plant Protection InstituteFaculty of Agricultural and Environmental SciencesSzent István UniversityGödöllőHungary
| | - Zoltán Havelda
- National Agricultural Research and Innovation CentreAgricultural Biotechnology InstituteGödöllőHungary
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Pesti R, Kontra L, Paul K, Vass I, Csorba T, Havelda Z, Várallyay É. Differential gene expression and physiological changes during acute or persistent plant virus interactions may contribute to viral symptom differences. PLoS One 2019; 14:e0216618. [PMID: 31051010 PMCID: PMC6499435 DOI: 10.1371/journal.pone.0216618] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 04/24/2019] [Indexed: 01/01/2023] Open
Abstract
Viruses have different strategies for infecting their hosts. Fast and acute infections result in the development of severe symptoms and may cause the death of the plant. By contrast, in a persistent interaction, the virus can survive within its host for a long time, inducing only mild symptoms. In this study, we investigated the gene expression changes induced in CymRSV-, crTMV-, and TCV-infected Nicotiana benthamiana and in PVX- and TMV-U1-infected Solanum lycopersicum plants after the systemic spread of the virus by two different high-throughput methods: microarray hybridization or RNA sequencing. Using these techniques, we were able to clearly differentiate between acute and persistent infections. We validated the gene expression changes of selected genes by Northern blot hybridization or by qRT-PCR. We show that, in contrast to persistent infections, the drastic shut-off of housekeeping genes, downregulation of photosynthesis-related transcripts and induction of stress genes are specific outcomes with acute infections. We also show that these changes are not a consequence of host necrosis or the presence of a viral silencing suppressor. Thermal imaging data and chlorophyll fluorescence measurements correlated very well with the molecular changes. We believe that the molecular and physiological changes detected during acute infections mostly contribute to virus symptom development. The observed characteristic physiological changes associated with economically more dangerous acute infections could serve as a basis for the elaboration of remote monitoring systems suitable for detecting developing virus infections in crops. Moreover, as molecular and physiological changes are characteristics of different types of virus lifestyles, this knowledge can support risk assessments of recently described novel viruses.
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Affiliation(s)
- Réka Pesti
- Diagnostic Group, Department of Genomics, Agricultural Biotechnology Research Institute, National Agricultural Research and Innovation Centre, Gödöllő, Hungary
| | - Levente Kontra
- Diagnostic Group, Department of Genomics, Agricultural Biotechnology Research Institute, National Agricultural Research and Innovation Centre, Gödöllő, Hungary
| | - Kenny Paul
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Imre Vass
- Institute of Plant Biology, Biological Research Centre, Szeged, Hungary
| | - Tibor Csorba
- Virology Group, Department of Plant Biotechnology, Agricultural Biotechnology Research Institute, National Agricultural Research and Innovation Centre, Gödöllő, Hungary
| | - Zoltán Havelda
- Plant Developmental Biology Group, Department of Plant Biotechnology, Agricultural Biotechnology Research Institute, National Agricultural Research and Innovation Centre, Gödöllő, Hungary
| | - Éva Várallyay
- Diagnostic Group, Department of Genomics, Agricultural Biotechnology Research Institute, National Agricultural Research and Innovation Centre, Gödöllő, Hungary
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9
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Taller D, Bálint J, Gyula P, Nagy T, Barta E, Baksa I, Szittya G, Taller J, Havelda Z. Correction: Expansion of Capsicum annum fruit is linked to dynamic tissue-specific differential expression of miRNA and siRNA profiles. PLoS One 2018; 13:e0203582. [PMID: 30161235 PMCID: PMC6117076 DOI: 10.1371/journal.pone.0203582] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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10
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Taller D, Bálint J, Gyula P, Nagy T, Barta E, Baksa I, Szittya G, Taller J, Havelda Z. Expansion of Capsicum annuum fruit is linked to dynamic tissue-specific differential expression of miRNA and siRNA profiles. PLoS One 2018; 13:e0200207. [PMID: 30044813 PMCID: PMC6059424 DOI: 10.1371/journal.pone.0200207] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 06/21/2018] [Indexed: 11/19/2022] Open
Abstract
Small regulatory RNAs, such as microRNAs (miRNAs) and small interfering RNAs (siRNAs) have emerged as important transcriptional and post-transcriptional regulators controlling a wide variety of physiological processes including fruit development. Data are, however, limited for their potential roles in developmental processes determining economically important traits of crops. The current study aimed to discover and characterize differentially expressed miRNAs and siRNAs in sweet pepper (Capsicum annuum) during fruit expansion. High-throughput sequencing was employed to determine the small regulatory RNA expression profiles in various fruit tissues, such as placenta, seed, and flesh at 28 and 40 days after anthesis. Comparative differential expression analyses of conserved, already described and our newly predicted pepper-specific miRNAs revealed that fruit expansion is accompanied by an increasing level of miRNA-mediated regulation of gene expression. Accordingly, ARGONAUTE1 protein, the primary executor of miRNA-mediated regulation, continuously accumulated to an extremely high level in the flesh. We also identified numerous pepper-specific, heterochromatin-associated 24-nt siRNAs (hetsiRNAs) which were extremely abundant in the seeds, as well as 21-nt and 24-nt phased siRNAs (phasiRNAs) that were expressed mainly in the placenta and the seeds. This work provides comprehensive tissue-specific miRNA and siRNA expression landscape for a developing pepper fruit. We identified several novel, abundantly expressing tissue- and pepper-specific small regulatory RNA species. Our data show that fruit expansion is associated with extensive changes in sRNA abundance, raising the possibility that manipulation of sRNA pathways may be employed to improve the quality and quantity of the pepper fruit.
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Affiliation(s)
- Dénes Taller
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Jeannette Bálint
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Péter Gyula
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Tibor Nagy
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Endre Barta
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Ivett Baksa
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - György Szittya
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - János Taller
- Department of Plant Science and Biotechnology, Georgikon Faculty, University of Pannonia, Keszthely, Hungary
| | - Zoltán Havelda
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Gödöllő, Hungary
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Tholt G, Kis A, Medzihradszky A, Szita É, Tóth Z, Havelda Z, Samu F. Could vectors' fear of predators reduce the spread of plant diseases? Sci Rep 2018; 8:8705. [PMID: 29880845 PMCID: PMC5992157 DOI: 10.1038/s41598-018-27103-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 05/29/2018] [Indexed: 11/09/2022] Open
Abstract
Predators influence the behaviour of prey and by doing so they potentially reduce pathogen transmission by a vector. Arthropod predators have been shown to reduce the consumption of plant biomass by pest herbivores, but their cascading non-consumptive effect on vector insects' feeding behaviour and subsequent pathogen transmission has not been investigated experimentally before. Here we experimentally examined predator-mediated pathogen transmission mechanisms using the plant pathogen Wheat Dwarf Virus that is transmitted by the leafhopper, Psammotettix alienus. We applied in situ hybridization to localize which leaf tissues were infected with transmitted virus DNA in barley host plants, proving that virus occurrence is restricted to phloem tissues. In the presence of the spider predator, Tibellus oblongus, we recorded the within leaf feeding behaviour of the herbivore using electrical penetration graph. The leafhopper altered its feeding behaviour in response to predation risk. Phloem ingestion, the feeding phase when virus acquisition occurs, was delayed and was less frequent. The phase when pathogen inoculation takes place, via the secretion of virus infected vector saliva, was shorter when predator was present. Our study thus provides experimental evidence that predators can potentially limit the spread of plant pathogens solely through influencing the feeding behaviour of vector organisms.
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Affiliation(s)
- G Tholt
- Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest, H-1022, Hungary.,Department of Systematic Zoology and Ecology, Faculty of Science, Institute of Biology, Eötvös Loránd University, 1/C Pázmány Péter Sétány, Budapest, H-1117, Hungary
| | - A Kis
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi A. út 4, Gödöllő, H-2100, Hungary
| | - A Medzihradszky
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi A. út 4, Gödöllő, H-2100, Hungary
| | - É Szita
- Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest, H-1022, Hungary
| | - Z Tóth
- Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest, H-1022, Hungary
| | - Z Havelda
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi A. út 4, Gödöllő, H-2100, Hungary
| | - F Samu
- Plant Protection Institute, Centre for Agricultural Research, Hungarian Academy of Sciences, Herman Ottó út 15, Budapest, H-1022, Hungary.
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12
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Várallyay É, Válóczi A, Ágyi Á, Burgyán J, Havelda Z. Plant virus-mediated induction of miR168 is associated with repression of ARGONAUTE1 accumulation. EMBO J 2017; 36:1641-1642. [PMID: 28572285 DOI: 10.15252/embj.201797083] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
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13
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Oláh E, Pesti R, Taller D, Havelda Z, Várallyay É. Non-targeted effects of virus-induced gene silencing vectors on host endogenous gene expression. Arch Virol 2016; 161:2387-93. [PMID: 27283101 DOI: 10.1007/s00705-016-2921-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2016] [Accepted: 05/31/2016] [Indexed: 11/28/2022]
Abstract
Virus-induced gene silencing (VIGS) uses recombinant viruses to study gene function; however, the effect of the virus vector itself on the gene expression of the host is not always considered. In our work, we investigated non-targeted gene expression changes of the host in order to see how often these changes appear. Effects of various VIGS vector infections were analysed by monitoring gene expression levels of housekeeping genes by Northern blot analysis in four different hosts. We found that non-targeted changes happens very often. More importantly, these non-targeted effects can cause drastic changes in the gene-expression pattern of host genes that are usually used as references in these studies. We have also found that in a tobacco rattle virus (TRV)-based VIGS, the presence of foreign sequences in the cloning site of the vector can also have a non-targeted effect, and even the use of an internal control can lead to unpredicted changes. Our results show that although VIGS is a very powerful technique, the VIGS vector, as a pathogen of the host, can cause unwanted changes in its gene-expression pattern, highlighting the importance of careful selection of both the genes to be tested and those to be used as references in the planned experiments.
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Affiliation(s)
- Enikő Oláh
- Plant Developmental Biology and Diagnostics Groups, Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Szent-Györgyi Albert utca 4., 100, Gödöllő, Hungary
| | - Réka Pesti
- Plant Developmental Biology and Diagnostics Groups, Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Szent-Györgyi Albert utca 4., 100, Gödöllő, Hungary
| | - Dénes Taller
- Plant Developmental Biology and Diagnostics Groups, Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Szent-Györgyi Albert utca 4., 100, Gödöllő, Hungary
| | - Zoltán Havelda
- Plant Developmental Biology and Diagnostics Groups, Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Szent-Györgyi Albert utca 4., 100, Gödöllő, Hungary
| | - Éva Várallyay
- Plant Developmental Biology and Diagnostics Groups, Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Szent-Györgyi Albert utca 4., 100, Gödöllő, Hungary.
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14
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Nagy T, Kis A, Poliska S, Barta E, Havelda Z, Marincs F. [Letter to the Editor] Comparison of small RNA next-generation sequencing with and without isolation of small RNA fraction. Biotechniques 2016; 60:273-8. [PMID: 27286803 DOI: 10.2144/000114423] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Accepted: 02/25/2016] [Indexed: 11/23/2022] Open
Abstract
Address correspondence to Ferenc Marincs, Agricultural Biotechnology Institute, NARIC, Szent-Györgyi Albert u. 4., Gödöllö, Hungary. E-mail: marincs.ferenc@abc.naik.hu.
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Affiliation(s)
- Tibor Nagy
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Gödöllö, Hungary
| | - András Kis
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Gödöllö, Hungary
| | - Szilárd Poliska
- Genomic Medicine and Bioinformatic Core Facility, Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Endre Barta
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Gödöllö, Hungary
| | - Zoltán Havelda
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Gödöllö, Hungary
| | - Ferenc Marincs
- Agricultural Biotechnology Institute, National Agricultural Research and Innovation Centre, Gödöllö, Hungary
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15
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Kis A, Tholt G, Ivanics M, Várallyay É, Jenes B, Havelda Z. Polycistronic artificial miRNA-mediated resistance to Wheat dwarf virus in barley is highly efficient at low temperature. Mol Plant Pathol 2016; 17:427-37. [PMID: 26136043 PMCID: PMC6638354 DOI: 10.1111/mpp.12291] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Infection of Wheat dwarf virus (WDV) strains on barley results in dwarf disease, imposing severe economic losses on crop production. As the natural resistance resources against this virus are limited, it is imperative to elaborate a biotechnological approach that will provide effective and safe immunity to a wide range of WDV strains. Because vector insect-mediated WDV infection occurs during cool periods in nature, it is important to identify a technology which is effective at lower temperature. In this study, we designed artificial microRNAs (amiRNAs) using a barley miRNA precursor backbone, which target different conservative sequence elements of the WDV strains. Potential amiRNA sequences were selected to minimize the off-target effects and were tested in a transient sensor system in order to select the most effective constructs at low temperature. On the basis of the data obtained, a polycistronic amiRNA precursor construct (VirusBuster171) was built expressing three amiRNAs simultaneously. The construct was transformed into barley under the control of a constitutive promoter. The transgenic lines were kept at 12-15 °C to mimic autumn and spring conditions in which major WDV infection and accumulation take place. We were able to establish a stable barley transgenic line displaying resistance to insect-mediated WDV infection. Our study demonstrates that amiRNA technology can be an efficient tool for the introduction of highly efficient resistance in barley against a DNA virus belonging to the Geminiviridae family, and this resistance is effective at low temperature where the natural insect vector mediates the infection process.
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Affiliation(s)
- András Kis
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi A. út 4, Gödöllő, H-2100, Hungary
- Crop Science PhD School, Plant Protection Programme, Szent István University, Páter Károly u. 1, Gödöllő, H-2100, Hungary
| | - Gergely Tholt
- Plant Protection Institute, Centre for Agricultural Research, , Hungarian Academy of Sciences, Herman Ottó út 15, Budapest, H-1022, Hungary
- Department of Systematic Zoology and Ecology, Faculty of Science, Institute of Biology, Eötvös Loránd University, 1/C Pázmány Péter Sétány, Budapest, H-1117, Hungary
| | - Milán Ivanics
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi A. út 4, Gödöllő, H-2100, Hungary
| | - Éva Várallyay
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi A. út 4, Gödöllő, H-2100, Hungary
| | - Barnabás Jenes
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi A. út 4, Gödöllő, H-2100, Hungary
| | - Zoltán Havelda
- National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi A. út 4, Gödöllő, H-2100, Hungary
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16
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Baksa I, Nagy T, Barta E, Havelda Z, Várallyay É, Silhavy D, Burgyán J, Szittya G. Identification of Nicotiana benthamiana microRNAs and their targets using high throughput sequencing and degradome analysis. BMC Genomics 2015; 16:1025. [PMID: 26626050 PMCID: PMC4667520 DOI: 10.1186/s12864-015-2209-6] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 11/12/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Nicotiana benthamiana is a widely used model plant species for research on plant-pathogen interactions as well as other areas of plant science. It can be easily transformed or agroinfiltrated, therefore it is commonly used in studies requiring protein localization, interaction, or plant-based systems for protein expression and purification. To discover and characterize the miRNAs and their cleaved target mRNAs in N. benthamiana, we sequenced small RNA transcriptomes and degradomes of two N. benthamiana accessions and validated them by Northern blots. RESULTS We used a comprehensive molecular approach to detect and to experimentally validate N. benthamiana miRNAs and their target mRNAs from various tissues. We identified 40 conserved miRNA families and 18 novel microRNA candidates and validated their target mRNAs with a genomic scale approach. The accumulation of thirteen novel miRNAs was confirmed by Northern blot analysis. The conserved and novel miRNA targets were found to be involved in various biological processes including transcription, RNA binding, DNA modification, signal transduction, stress response and metabolic process. Among the novel miRNA targets we found the mRNA of REPRESSOR OF SILENCING (ROS1). Regulation of ROS1 by a miRNA provides a new regulatory layer to reinforce transcriptional gene silencing by a post-transcriptional repression of ROS1 activity. CONCLUSIONS The identified conserved and novel miRNAs along with their target mRNAs also provides a tissue specific atlas of known and new miRNA expression and their cleaved target mRNAs of N. benthamiana. Thus this study will serve as a valuable resource to the plant research community that will be beneficial well into the future.
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Affiliation(s)
- Ivett Baksa
- Institute of Plant Biotechnology, National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi Albert ut 4, H-2100, Gödöllő, Hungary.
| | - Tibor Nagy
- Institute of Plant Biotechnology, National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi Albert ut 4, H-2100, Gödöllő, Hungary.
| | - Endre Barta
- Institute of Plant Biotechnology, National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi Albert ut 4, H-2100, Gödöllő, Hungary.
| | - Zoltán Havelda
- Institute of Plant Biotechnology, National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi Albert ut 4, H-2100, Gödöllő, Hungary.
| | - Éva Várallyay
- Institute of Plant Biotechnology, National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi Albert ut 4, H-2100, Gödöllő, Hungary.
| | - Dániel Silhavy
- Institute of Plant Biotechnology, National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi Albert ut 4, H-2100, Gödöllő, Hungary.
| | - József Burgyán
- Institute of Plant Biotechnology, National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi Albert ut 4, H-2100, Gödöllő, Hungary.
| | - György Szittya
- Institute of Plant Biotechnology, National Agricultural Research and Innovation Centre, Agricultural Biotechnology Institute, Szent-Györgyi Albert ut 4, H-2100, Gödöllő, Hungary.
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17
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Várallyay É, Oláh E, Havelda Z. Independent parallel functions of p19 plant viral suppressor of RNA silencing required for effective suppressor activity. Nucleic Acids Res 2014; 42:599-608. [PMID: 24062160 PMCID: PMC3874164 DOI: 10.1093/nar/gkt846] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2013] [Revised: 08/09/2013] [Accepted: 08/30/2013] [Indexed: 11/12/2022] Open
Abstract
Plant viruses ubiquitously mediate the induction of miR168 trough the activities of viral suppressors of RNA silencing (VSRs) controlling the accumulation of ARGONAUTE1 (AGO1), one of the main components of RNA silencing based host defence system. Here we used a mutant Tombusvirus p19 VSR (p19-3M) disabled in its main suppressor function, small interfering RNA (siRNA) binding, to investigate the biological role of VSR-mediated miR168 induction. Infection with the mutant virus carrying p19-3M VSR resulted in suppressed recovery phenotype despite the presence of free virus specific siRNAs. Analysis of the infected plants revealed that the mutant p19-3M VSR is able to induce miR168 level controlling the accumulation of the antiviral AGO1, and this activity is associated with the enhanced accumulation of viral RNAs. Moreover, saturation of the siRNA-binding capacity of p19 VSR mediated by defective interfering RNAs did not influence the miR168-inducing activity. Our data indicate that p19 VSR possesses two independent silencing suppressor functions, viral siRNA binding and the miR168-mediated AGO1 control, both of which are required to efficiently cope with the RNA-silencing based host defence. This finding suggests that p19 VSR protein evolved independent parallel capacities to block the host defence at multiple levels.
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Affiliation(s)
- Éva Várallyay
- Agricultural Biotechnology Center, Institute for Plant Biotechnology, Plant Developmental Biology Group, Szent-Györgyi A. út 4, Gödöllő H-2100, Hungary
| | - Enikő Oláh
- Agricultural Biotechnology Center, Institute for Plant Biotechnology, Plant Developmental Biology Group, Szent-Györgyi A. út 4, Gödöllő H-2100, Hungary
| | - Zoltán Havelda
- Agricultural Biotechnology Center, Institute for Plant Biotechnology, Plant Developmental Biology Group, Szent-Györgyi A. út 4, Gödöllő H-2100, Hungary
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18
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Abstract
Various plant viruses ubiquitously mediate the induction of miR168, resulting in the control of ARGONAUTE 1 (AGO1), which is the pivotal component of the microRNA (miRNA) regulation pathway and can also exhibit antiviral function. Here, we demonstrate that miR168-driven control of AGO1 can persist for a long time in virus-infected plants and can be an important component of symptom development. We also show that infection of RNA viruses belonging to various genera is associated with the transcriptional induction of the MIR168 precursor gene. Moreover, in a transient expression study, we reveal that different unrelated viral suppressors of RNA silencing (VSRs) are responsible for the enhanced accumulation of miR168. The induction of miR168 accumulation is an early function of VSRs and this activity is associated with the control of the endogenous AGO1 protein level. The common ability of unrelated VSRs to induce the miR168 level implies that this activity might be a component of the host defence suppression in plant-virus interactions.
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Affiliation(s)
- Eva Várallyay
- Plant Developmental Biology Group, Agricultural Biotechnology Center, Szent Györgyi A. út 4, Gödöllő, H-2100, Hungary
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19
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Abstract
MicroRNAs (miRNAs) are short, about 21 nucleotides in length, non-coding, regulatory RNA molecules representing a new layer in post-transcriptional gene expression regulation. Spatial and temporal analysis of miRNA accumulation by in situ analyses is the prerequisite of understanding the precise biological functions of miRNAs. Since miRNAs are very short molecules, their in situ analysis is technically demanding. Our method is based on the usage of highly sensitive LNA-modified oligonucleotide probes. LNA modification significantly enhances the sensitivity and specificity of miRNA detecting probes and provides relatively easy in situ miRNA detection. Here, we describe a protocol for this challenging technique step by step, in order to help every user to achieve success.
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20
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Abstract
The infection and replication of viruses in the host induce diverse mechanisms for combating viral infection. One of the best-studied antiviral defence mechanisms is based on RNA silencing. Consistently, several viral suppressors of RNA silencing (VSRs) have been identified from almost all plant virus genera, which are surprisingly diverse within and across kingdoms, exhibiting no obvious sequence similarities. VSRs efficiently inhibit host antiviral responses by interacting with the key components of cellular silencing machinery, often mimicking their normal cellular functions. Recent findings have revealed that the impact of VSRs on endogenous pathways is more complex and profound than had been estimated thus far. This review highlights the current understanding of and new insights into the mechanisms and functions of plant VSRs.
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Affiliation(s)
- József Burgyán
- Istituto di Virologia Vegetale, CNR, Strada Delle Cacce 73, Torino, Italy.
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21
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Várallyay E, Lichner Z, Sáfrány J, Havelda Z, Salamon P, Bisztray G, Burgyán J. Development of a virus induced gene silencing vector from a legumes infecting tobamovirus. Acta Biol Hung 2010; 61:457-69. [PMID: 21112837 DOI: 10.1556/abiol.61.2010.4.9] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Medicago truncatula, the model plant of legumes, is well characterized, but there is only a little knowledge about it as a viral host. Viral vectors can be used for expressing foreign genes or for virus-induced gene silencing (VIGS), what is a fast and powerful tool to determine gene functions in plants. Viral vectors effective on Nicotiana benthamiana have been constructed from a number of viruses, however, only few of them were effective in other plants. A Tobamovirus, Sunnhemp mosaic virus (SHMV) systemically infects Medicago truncatula without causing severe symptoms. To set up a viral vector for Medicago truncatula, we prepared an infectious cDNA clone of SHMV. We constructed two VIGS vectors differing in the promoter element to drive foreign gene expression. The vectors were effective both in the expression and in the silencing of a transgene Green Fluorescent Protein (GFP) and in silencing of an endogenous gene Phytoene desaturase (PDS) on N. benthamiana. Still only one of the vectors was able to successfully silence the endogenous Chlorata 42 gene in M. truncatula.
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Affiliation(s)
- Eva Várallyay
- Agricultural Biotechnology Centre, Plant Biology Institute, Gödöllő, Hungary.
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22
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Várallyay É, Válóczi A, Ágyi Á, Burgyán J, Havelda Z. Plant virus-mediated induction of miR168 is associated with repression of ARGONAUTE1 accumulation. EMBO J 2010; 29:3507-19. [PMID: 20823831 PMCID: PMC2964164 DOI: 10.1038/emboj.2010.215] [Citation(s) in RCA: 185] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 08/12/2010] [Indexed: 11/09/2022] Open
Abstract
Virus infections induce the expression of ARGONAUTE1 (AGO1) mRNA and in parallel enhance the accumulation of miR168 (regulator of AGO1 mRNA). Here, we show that in virus-infected plants the enhanced expression of AGO1 mRNA is not accompanied by increased AGO1 protein accumulation. We also show that the induction of AGO1 mRNA level is a part of the host defence reaction, whereas the induction of miR168, which overlaps spatially with virus-occupied sectors, is mediated mainly by the Tombusvirus p19 RNA-silencing suppressor. The absence of p19 results in the elimination of miR168 induction and accompanied with the enhanced accumulation of AGO1 protein. In transient expression study, p19 mediates the induction of miR168 and the down-regulation of endogenous AGO1 level. P19 is not able to efficiently bind miR168 in virus-infected plants, indicating that this activity is uncoupled from the small RNA-binding capacity of p19. Our results imply that plant viruses can inhibit the translational capacity of AGO1 mRNA by modulating the endogenous miR168 level to alleviate the anti-viral function of AGO1 protein.
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Affiliation(s)
- Éva Várallyay
- Agricultural Biotechnology Center, Plant Virology and Bioinformatics Group, Gödöllő, Hungary
| | - Anna Válóczi
- Department of Stem Cell Biology, University of Heidelberg, Heidelberg, Germany
| | - Ákos Ágyi
- Agricultural Biotechnology Center, Plant Virology and Bioinformatics Group, Gödöllő, Hungary
| | - József Burgyán
- Agricultural Biotechnology Center, Plant Virology and Bioinformatics Group, Gödöllő, Hungary
- Istituto di Virologia Vegetale, CNR Strada delle Cacce, Torino, Italy
| | - Zoltán Havelda
- Agricultural Biotechnology Center, Plant Virology and Bioinformatics Group, Gödöllő, Hungary
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23
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Abstract
A spatial and temporal analysis of miRNA accumulation by in situ analyses is the prerequisite of understanding the precise biological functions of miRNAs. Since miRNAs are very short molecules, their in situ analysis is technically demanding. Here, we describe a protocol for miRNA in situ detection in plants based on LNA-modified oligonucleotides probes. LNA modification significantly enhances the sensitivity and specificity of miRNA detecting probes and provides relatively easy in situ miRNA detection.
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24
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Abstract
MicroRNAs (miRNAs) are short, about 21 nucleotides in length, noncoding, regulatory RNA molecules representing a new layer in post-transcriptional regulation of gene expression. Intensive miRNA research has necessitated the development of effective miRNA detection methods such as northern analyses, quantitative real-time PCR and microarrays. Northern analysis is a widely used method for miRNA analyses because it is generally a readily available technology for laboratories and does not require special equipment and technical knowledge. The major disadvantages of the northern blot technology using the traditional DNA oligonucleotide probes are its poor sensitivity and the high time consumption. Here, we describe an improved protocol for miRNA northern blot analysis, which includes RNA extraction, polyacrylamide gel electrophoresis and northern blotting, and the hybridization and detection of locked nucleic acid (LNA)-modified oligonucleotide probes. The use of LNA-modified oligonucleotide probes allows highly sensitive and specific detection of mature miRNAs and also dramatically reduces the period of time necessary for carrying out the protocol. Using this approach, the hybridization, washing and signal-detection steps can be performed ideally in 4 h.
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Affiliation(s)
- Eva Várallyay
- Agricultural Biotechnology Center, Plant Virology Group, Szent-Györgyi Albert ut 4, Gödöllõ H-2100, Hungary
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25
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Abstract
Understanding of virus infection-induced alterations in host plant gene expression and metabolism leading to the development of virus disease symptoms is both scientifically and economically important. Here, we show that viruses belonging to various RNA virus families are able to induce efficient host gene mRNA downregulation (shut-off) in systemically infected leaves. We demonstrate that the host gene mRNA shut-off overlaps spatially with virus-occupied sectors, indicating the direct role of virus accumulation in this phenomenon. The establishment of shut-off was not directly connected to active viral replication or the RNA-silencing machinery. Importantly, the induced shut-off phenomenon persisted for several weeks, resulting in severe deficiency of mRNA for important housekeeping genes in the infected plants. Interestingly, we found that some other RNA viruses do not induce or only slightly induce the shut-off phenomenon for the same set of genes, implicating genetic determination in this process. Nuclear run-on experiments suggest that plant viruses, similarly to animal viruses, mediate suppression of host mRNA synthesis in the nucleus. By investigating various host-virus interactions, we revealed a correlation between the intensity of the shut-off phenomenon and the severity of disease symptoms. Our data suggest that efficient and persistent downregulation of host genes may be an important component of symptom development in certain host-virus interactions.
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Affiliation(s)
- Zoltán Havelda
- Agricultural Biotechnology Center, Plant Virology Group, Szent-Györgyi Albert út 4, Gödöllo, H-2001, Hungary.
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26
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Abstract
Small RNAs such as small interfering RNAs (siRNAs) and microRNAs (miRNAs) play crucial roles in establishing general host defense mechanisms against viral infections in plants and the development of disease symptoms. Understanding these fundamental processes requires the sensitive and specific detection of small RNA species. However, because of the small size of miRNAs and siRNAs, their detection is technically demanding. Here, we describe methods for robust and sensitive detection of small RNAs by Northern blot analysis and in situ hybridization.
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Affiliation(s)
- Sakari Kauppinen
- Wilhelm Johannsen Center for Functional Genome Research, Department of Cellular and Molecular Medicine, University of Copenhagen, DK-2200 Copenhagen N, Denmark
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27
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Abstract
The ability to combine nucleic acid hybridisation or immunospecific reactions with structural and ultrastructural analysis of virus-infected tissues has provided the opportunity to resolve the spatial details of infection with respect to the production of virus-specific products and the nature of the host response. These technologies may seem lengthy and complex but offer high rewards in terms of revealing the details of host-virus interactions not otherwise accessible.
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Affiliation(s)
- Andrew J Maule
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, UK
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28
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Várallyay E, Burgyán J, Havelda Z. Detection of microRNAs by Northern blot analyses using LNA probes. Methods 2007; 43:140-5. [PMID: 17889801 DOI: 10.1016/j.ymeth.2007.04.004] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2006] [Revised: 04/11/2007] [Accepted: 04/13/2007] [Indexed: 11/15/2022] Open
Abstract
MicroRNAs (miRNAs) are small, endogenous, non-coding RNA species, about 21 nucleotides in length, which modulate the expression of animal and plant target genes at the post-transcriptional level. It has been shown that miRNA based gene regulation plays a pivotal role in pathways involved in growth and development. Understanding miRNA mediated processes requires new technologies enabling efficient detection of small RNA species. Here we report the optimization of a miRNA Northern blot detection method based on LNA (locked nucleic acid)-modified oligonucleotide hybridization. This technique allows sensitive and highly specific detection of mature miRNAs.
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Affiliation(s)
- Eva Várallyay
- Agricultural Biotechnology Center, Szent-Györgyi Albert ut 4, Gödöllö H-2100, Hungary
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29
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Válóczi A, Várallyay E, Kauppinen S, Burgyán J, Havelda Z. Spatio-temporal accumulation of microRNAs is highly coordinated in developing plant tissues. Plant J 2006; 47:140-51. [PMID: 16824182 DOI: 10.1111/j.1365-313x.2006.02766.x] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
MicroRNAs (miRNAs) are an abundant class of small, endogenous non-protein-coding RNAs, approximately 21 nucleotides in length, that modulate the expression of animal and plant target genes at the post-transcriptional level. Recent work has shown that miRNA-based gene regulation plays a crucial role in pathways involved in plant growth and development. However, knowledge about the timing and spatial regulation of plant miRNA expression is still limited. Here we used in situ analysis to demonstrate that miRNAs accumulate spatially and temporally in a highly restricted manner in Nicotiana benthamiana and Arabidopsis thaliana. The presence of the seven investigated miRNAs was characteristic of the developing organs, implying a role in cell-fate establishment, differentiation and cell-cycle progression. Spatial analyses revealed that six of the studied miRNAs were present in vascular bundles, suggesting that mobile miRNAs in the phloem could contribute to the coordination of organogenesis and development. The obvious absence of miR167 in vascular bundles represented an exception to this observation, implying an active process in regulating the presence of miRNAs in the vascular system. Taken together, our results imply that the spatially and temporally organized accumulation of miRNAs plays a pivotal role in fine-tuning of target gene expression in plant development.
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Affiliation(s)
- Anna Válóczi
- Agricultural Biotechnology Center, Plant Biology Institute, Szent-Györgyi Albert út 4, Gödöllo, H-2001, Hungary
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30
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Hornyik C, Havelda Z, Burgyán J. Identification of sequence elements of tombusvirus-associated defective interfering RNAs required for symptom modulation. Arch Virol 2006; 151:625-33. [PMID: 16328149 DOI: 10.1007/s00705-005-0651-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2005] [Accepted: 08/18/2005] [Indexed: 10/25/2022]
Abstract
Defective interfering (DI) RNAs of tombusviruses are short, non-coding, symptom-modulating RNAs originating from the viral genome. The presence of homologous DI RNA in virus infection attenuates the otherwise lethal viral symptoms. Nicotiana benthamiana plants infected with tomato bushy stunt tombusvirus pepper isolate (TBSV-P) show severe symptoms, which culminate in the death of the plant. In contrast, plants co-inoculated with TBSV-P and TBSV-P-derived DI RNA display attenuated symptoms. However, co-inoculation of TBSV-P with heterologous DI RNA, originating from Carnation Italian ringspot tombusvirus results in development of apical necrotic symptoms. To localize the symptom-determining factors on DI RNA genome, chimeras of protective and non-protective DI RNAs have been constructed. All chimeras were biologically active and accumulated to a high level in the presence of helper virus. We identified a 5' proximal sequence element of the DI RNA as the most important symptom determinant region. However, our results demonstrated that the symptom modulating ability of this region is also influenced by the sequence composition of whole DI RNAs.
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Affiliation(s)
- C Hornyik
- Agricultural Biotechnology Center, Plant Biology Institute, Gödölloo, Hungary
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Mérai Z, Kerényi Z, Molnár A, Barta E, Válóczi A, Bisztray G, Havelda Z, Burgyán J, Silhavy D. Aureusvirus P14 is an efficient RNA silencing suppressor that binds double-stranded RNAs without size specificity. J Virol 2005; 79:7217-26. [PMID: 15890960 PMCID: PMC1112109 DOI: 10.1128/jvi.79.11.7217-7226.2005] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2004] [Accepted: 01/17/2005] [Indexed: 11/20/2022] Open
Abstract
RNA silencing is a conserved eukaryotic gene regulatory system in which sequence specificity is determined by small RNAs. Plant RNA silencing also acts as an antiviral mechanism; therefore, viral infection requires expression of a silencing suppressor. The mechanism and the evolution of silencing suppression are still poorly understood. Tombusvirus open reading frame (ORF) 5-encoded P19 is a size-selective double-stranded RNA (dsRNA) binding protein that suppresses silencing by sequestering double-stranded small interfering RNAs (siRNAs), the specificity determinant of the antiviral silencing system. To better understand the evolution of silencing suppression, we characterized the suppressor of the type member of Aureusviruses, the closest relatives of the genus Tombusvirus. We show that the Pothos latent virus (PoLV) ORF 5-encoded P14 is an efficient suppressor of both virus- and transgene-induced silencing. Findings that in vitro P14 binds dsRNAs and double-stranded siRNAs without obvious size selection suggest that P14, unlike P19, can suppress silencing by sequestering both long dsRNA and double-stranded siRNA components of the silencing machinery. Indeed, P14 prevents the accumulation of hairpin transcript-derived siRNAs, indicating that P14 inhibits inverted repeat-induced silencing by binding the long dsRNA precursors of siRNAs. However, viral siRNAs accumulate to high levels in PoLV-infected plants; therefore, P14 might inhibit virus-induced silencing by sequestering double-stranded siRNAs. Finally, sequence analyses suggest that P14 and P19 suppressors diverged from an ancient dsRNA binding suppressor that evolved as a nested protein within the common ancestor of aureusvirus-tombusvirus movement proteins.
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Affiliation(s)
- Zsuzsanna Mérai
- Agricultural Biotechnology Center, Plant Science Institute, P.O. Box 411, H-2101 Gödöllö, Hungary
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Havelda Z, Hornyik C, Válóczi A, Burgyán J. Defective interfering RNA hinders the activity of a tombusvirus-encoded posttranscriptional gene silencing suppressor. J Virol 2005; 79:450-7. [PMID: 15596838 PMCID: PMC538711 DOI: 10.1128/jvi.79.1.450-457.2005] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2004] [Accepted: 08/13/2004] [Indexed: 11/20/2022] Open
Abstract
Defective interfering (DI) RNAs are subviral replicons originating from the viral genome and are associated with many plant RNA viruses and nearly all animal RNA viruses. The presence of DI RNAs in tombusvirus-infected plants reduces the accumulation of helper virus RNA and results in the development of attenuated symptoms similar to those caused by tombusviruses defective in p19, the posttranscriptional gene silencing (PTGS) suppressor. In situ analysis of infected plants containing DI RNAs revealed that the extent of virus infection was spatially restricted as was found for p19-defective tombusvirus. Previously, p19 was shown to suppress PTGS by sequestering the small interfering RNAs (siRNAs), which act as the specificity determinant for PTGS. Our results demonstrate that DI RNAs dramatically elevate the level of virus-specific siRNAs in viral infections, resulting in the saturation of p19 and the accumulation of unbound siRNAs. Moreover, we showed that, at low temperature, where PTGS is inhibited, DI RNAs are not able to efficiently interfere with virus accumulation and protect the plants. These data show that the activation of PTGS plays a pivotal role in DI RNA-mediated interference. Our data also support a role for 21-nucleotide siRNAs in PTGS signaling.
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Affiliation(s)
- Zoltán Havelda
- Agricultural Biotechnology Center, Institute of Plant Biology, Gödöllo, Hungary.
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Válóczi A, Hornyik C, Varga N, Burgyán J, Kauppinen S, Havelda Z. Sensitive and specific detection of microRNAs by northern blot analysis using LNA-modified oligonucleotide probes. Nucleic Acids Res 2004; 32:e175. [PMID: 15598818 PMCID: PMC545470 DOI: 10.1093/nar/gnh171] [Citation(s) in RCA: 634] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We describe here a new method for highly efficient detection of microRNAs by northern blot analysis using LNA (locked nucleic acid)-modified oligonucleotides. In order to exploit the improved hybridization properties of LNA with their target RNA molecules, we designed several LNA-modified oligonucleotide probes for detection of different microRNAs in animals and plants. By modifying DNA oligonucleotides with LNAs using a design, in which every third nucleotide position was substituted by LNA, we could use the probes in northern blot analysis employing standard end-labelling techniques and hybridization conditions. The sensitivity in detecting mature microRNAs by northern blots was increased by at least 10-fold compared to DNA probes, while simultaneously being highly specific, as demonstrated by the use of different single and double mismatched LNA probes. Besides being highly efficient as northern probes, the same LNA-modified oligonucleotide probes would also be useful for miRNA in situ hybridization and miRNA expression profiling by LNA oligonucleotide microarrays.
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Affiliation(s)
- Anna Válóczi
- Agricultural Biotechnology Center, Szent-Györgyi Albert ut 4, Gödöll H-2100, Hungary
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Abstract
Although many subviral RNAs reduce or intensify disease symptoms caused by the helper virus, only recently have clues concerning the mechanism of disease modulation been revealed. New models for DI RNA-mediated reduction in helper virus levels and symptom attenuation include DI RNA enhancement of posttranscriptional gene silencing (PTGS), which is an antiviral defense mechanism in plants. Symptom enhancement by the satRNA of Cucumber mosaic virus is caused by minus-strand induction of the programmed cell death pathway. In contrast, symptom enhancement by satC of Turnip crinkle virus is due to satC interference with virion formation, leading to increased levels of free coat protein, which is the viral suppressor of PTGS. Mutualism between satRNA and helper virus can be seen for the satRNA of Groundnut rosette virus, which contributes to the virus by allowing virion assembly. These novel findings are leading to re-evaluation of the relationships between subviral RNAs, helper viruses, and hosts.
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Affiliation(s)
- Anne E Simon
- Department of Cell Biology and Molecular Genetics, University of Maryland College Park, College Park, Maryland 20742, USA.
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Havelda Z, Hornyik C, Crescenzi A, Burgyán J. In situ characterization of Cymbidium Ringspot Tombusvirus infection-induced posttranscriptional gene silencing in Nicotiana benthamiana. J Virol 2003; 77:6082-6. [PMID: 12719602 PMCID: PMC154021 DOI: 10.1128/jvi.77.10.6082-6086.2003] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2002] [Accepted: 02/17/2003] [Indexed: 11/20/2022] Open
Abstract
In plants, posttranscriptional gene silencing (PTGS) is an ancient and effective defense mechanism against viral infection. A number of viruses encode proteins that suppress virus-activated PTGS. The p19 protein of tombusviruses is a potent PTGS suppressor which interferes with the onset of PTGS-generated systemic signaling and is not required for viral replication or for viral movement in Nicotiana benthamiana. This unique feature of p19 suppressor allowed us to analyze the mechanism of PTGS-based host defense and its viral suppression without interfering with other viral functions. In contrast to the necrotic symptoms caused by wild-type tombusvirus, the infection of p19-defective mutant virus results in the development of a typical PTGS-associated recovery phenotype in N. benthamiana. In this report we show the effect of PTGS on the viral infection process for N. benthamiana infected with either wild-type Cymbidium Ringspot Tombusvirus (CymRSV) or a p19-defective mutant (Cym19stop). In situ analyses of different virus-derived products revealed that PTGS is not able to reduce accumulation of virus in primary infected cells regardless of the presence of p19 PTGS suppressor. We also showed that both CymRSV and Cym19stop viruses move systemically in the vasculature, with similar efficiencies. However, in contrast to the uniform accumulation of CymRSV throughout systemically infected leaves, the presence of Cym19stop virus was confined to and around the vascular bundles. These results suggest that the role of p19 is to prevent the onset of mobile signal-induced systemic PTGS ahead of the viral infection front, leading to generalized infection.
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Affiliation(s)
- Zoltán Havelda
- Agricultural Biotechnology Centre, H-2101 Gödöllõ, Hungary.
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Szittya G, Silhavy D, Molnár A, Havelda Z, Lovas Á, Lakatos L, Bánfalvi Z, Burgyán J. Low temperature inhibits RNA silencing-mediated defence by the control of siRNA generation. EMBO J 2003; 22:633-40. [PMID: 12554663 PMCID: PMC140757 DOI: 10.1093/emboj/cdg74] [Citation(s) in RCA: 304] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2002] [Revised: 12/06/2002] [Accepted: 12/09/2002] [Indexed: 11/14/2022] Open
Abstract
Temperature dramatically affects plant-virus interactions. Outbreaks of virus diseases are frequently associated with low temperature, while at high temperature viral symptoms are often attenuated (heat masking) and plants rapidly recover from virus diseases. However, the underlying mechanisms of these well-known observations are not yet understood. RNA silencing is a conserved defence system of eukaryotic cells, which operates against molecular parasites including viruses and transgenes. Here we show that at low temperature both virus and transgene triggered RNA silencing are inhibited. Therefore, in cold, plants become more susceptible to viruses, and RNA silencing-based phenotypes of transgenic plants are lost. Consistently, the levels of virus- and transgene-derived small (21-26 nucleotide) interfering (si) RNAs-the central molecules of RNA silencing-mediated defence pathways-are dramatically reduced at low temperature. In contrast, RNA silencing was activated and the amount of siRNAs gradually increased with rising temperature. However, temperature does not influence the accumulation of micro (mi) RNAs, which play a role in developmental regulation, suggesting that the two classes of small (si and mi) RNAs are generated by different nuclease complexes.
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Affiliation(s)
| | | | | | | | | | | | | | - József Burgyán
- Agricultural Biotechnology Center, Plant Biology, PO Box 411, H-2101, Gödöllö, Hungary
Corresponding author e-mail:
G.Szittya and D.Silhavy contributed equally to this work
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Havelda Z, Maule AJ. Complex spatial responses to cucumber mosaic virus infection in susceptible Cucurbita pepo cotyledons. Plant Cell 2000; 12:1975-86. [PMID: 11041891 PMCID: PMC149134 DOI: 10.1105/tpc.12.10.1975] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2000] [Accepted: 08/04/2000] [Indexed: 05/20/2023]
Abstract
Cucumber mosaic virus infection of its susceptible host Cucurbita pepo results in a program of biochemical changes after virus infection. Applying a spatial analysis to expanding infected lesions, we investigated the relationship between the changes in enzyme activity and gene expression. Patterns of altered expression were seen that could not be detected by RNA gel blot analysis. For all the host genes studied, there was a downregulation (shutoff) of expression within the lesion. In addition, two distinct types of upregulation were observed. The expression of heat shock protein 70 (HSP70) and NADP(+)-dependent malic enzyme (NADP-ME) showed induction in apparently uninfected cells ahead of the infection. This response was more localized than the upregulation exhibited by catalase expression, which occurred throughout the uninfected regions of the tissue. The experiments showed that virus infection induced immediate and subsequent changes in gene expression by the host and that the infection has the potential to give advance signaling of the imminent infection.
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Affiliation(s)
- Z Havelda
- John Innes Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom
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Havelda Z, Szittya G, Burgyán J. Characterization of the molecular mechanism of defective interfering RNA-mediated symptom attenuation in tombusvirus-infected plants. J Virol 1998; 72:6251-6. [PMID: 9621100 PMCID: PMC110454 DOI: 10.1128/jvi.72.7.6251-6256.1998] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Different tombusviruses were able to support the replication of either homologous or heterologous defective interfering (DI) RNAs, and those infected plants usually developed typical attenuated symptoms. However, in some helper virus-DI RNA combinations the inoculated plants were necrotized, although they contained a high level of DI RNA, suggesting that the accumulation of DI RNA and the resulting suppression of genomic RNA replication were not directly responsible for the symptom attenuation. Moreover, the 19-kDa protein product of ORF 5, which is known to play a crucial role in necrotic symptom development, accumulated at the same level in the infected plants in the presence of protective homologous DI RNA and in the presence of nonprotective heterologous DI RNA. It was also demonstrated, by chimeric helper viruses, that the ability of heterologous DI RNA to protect the virus-infected plants against systemic necrosis is determined by the 5'-proximal region of the helper virus genome. The results presented suggest that DI RNA-mediated protection did not operate via the specific inhibition of 19-kDa protein expression but, more likely, DI RNAs in protective DI-helper virus combinations specifically interacted with viral products, preventing the induction of necrotic symptoms.
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Affiliation(s)
- Z Havelda
- Agricultural Biotechnology Center, Plant Science Institute, 2101 Gödöllö, Hungary
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Molnár A, Havelda Z, Dalmay T, Szutorisz H, Burgyán J. Complete nucleotide sequence of tobacco necrosis virus strain DH and genes required for RNA replication and virus movement. J Gen Virol 1997; 78 ( Pt 6):1235-9. [PMID: 9191913 DOI: 10.1099/0022-1317-78-6-1235] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The complete genome sequence of tobacco necrosis virus strain D (Hungarian isolate, TNV-DH) was determined. The genome (3762 nt) has an organization identical to that reported for TNV-D. Highly infectious synthetic transcripts from a full-length TNV-DH cDNA clone were prepared, the first infectious necrovirus transcript reported. This clone was used for reverse genetic studies to map the viral genes required for replication and movement. Protoplast inoculation with delta 22 and delta 82 mutants revealed that both the 22 kDa and 82 kDa gene products are required for RNA replication. Although the products of three small central genes (p7(1), p7a and p7b) were not essential for RNA replication in protoplasts, mutations in these ORFs prevented infection of plants. In contrast, viral RNA accumulation and cell-to-cell movement were observed in the inoculated, but not the systemically infected, leaves of Nicotiana benthamiana challenged with RNA lacking the intact coat protein (CP) gene. These results strongly suggest that p7(1), p7a, p7b and CP are involved in TNV-DH cell-to-cell and long-distance movement, respectively.
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Affiliation(s)
- A Molnár
- Agricultural Biotechnology Center, Plant Science Institute, Gödölló, Hungary
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Abstract
Mutational analysis of defective interfering (DI) RNAs of Cymbidium ringspot virus (CymRSV) was used to study the mechanism of DI RNA evolution. It was shown that a highly base-paired structure in the 3' region of the longer DI RNA directed the formation of smaller DI RNA molecules. Mutations which increased the stability of the computer-predicted, highly structured 3' region of the longest DI RNA of CymRSV significantly enhanced the generation and accumulation of the smaller derivatives. Sequence analysis of smaller progeny molecules revealed that the highly base-paired region was deleted from the precursor DI RNA. Moreover, sites of recombination were found in other regions of the DI RNA progenies due to transposition of the highly base-paired structure. It is likely that the deletion event was structure- and not sequence-specific, and operated when a foreign sequence containing a 37-nt-long base-paired stem was inserted at the appropriate position of DI RNA.
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Affiliation(s)
- Z Havelda
- Agricultural Biotechnology Center, Plant Science Institute, Gödölló, Hungary
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Abstract
Defective interfering (DI) RNA of cymbidium ringspot tombusvirus (CymRSV) was used to identify the cis-acting nature of the last 77-nt sequence of the viral genome which is required for DI RNA accumulation. The 3'-terminal cis-essential domain of both genomic and DI RNAs can be folded into a stable stem-loop structure composed of three hairpins and two short non-base-paired regions. None of the three conserved stem-loops can be deleted without abolishing the infectivity of DI RNA. Similarly, those mutants in which base-paired stem regions were disrupted by single-, double-, or triple-base substitutions were unable to replicate. However, when the original structures were reconstructed by compensatory mutations the viability of the molecules was also restored. Limited mutation (1 or 2 nt) in the non-base-paired region did not show any significant effect on viral replication. Our results strongly suggest that the proposed structure for the 3' terminus of the viral genome is very important for viral RNA replication. It is very likely that the function of this structure is to promote the minus-strand synthesis of CymRSV DI RNA. Evidence is provided that the proposed 3'-terminal structure is relevant not only for CymRSV DI but for genomic RNA as well.
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Affiliation(s)
- Z Havelda
- Agricultural Biotechnology Center, Plant Science Institute, Gödöllô, Hungary
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Havelda Z, Dalmay T, Burgyán J. Localization of cis-acting sequences essential for cymbidium ringspot tombusvirus defective interfering RNA replication. J Gen Virol 1995; 76 ( Pt 9):2311-6. [PMID: 7561770 DOI: 10.1099/0022-1317-76-9-2311] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The smallest defective interfering RNA (DI-2) of cymbidium ringspot tombusvirus (CyRSV) was used to identify the cis-acting sequences necessary for its replication by making a series of deletions throughout the 404 nt long molecule and testing the biological activity of mutants. Deletion or substitution of the conserved sequence blocks (A, B and C) always yielded inactive molecules. The deletion of only a few nucleotides could be tolerated beyond the natural deletion sites in blocks A and B. However, either half of block C1 (34 nt) and the first 25 nt of C2 (102 nt) could be deleted without loss of infectivity. It was also demonstrated that either one of the two halves of block C1 was specifically required for replication. We suggest that the last 77 nt of the viral genome and either half of block C1 represent the complementary strand promoter sequence recognized by the viral replicase.
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Affiliation(s)
- Z Havelda
- Agricultural Biotechnology Center, Plant Science Institute, Gödöllõ, Hungary
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