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Regulation of RNA-Dependent RNA Polymerase 1 and Isochorismate Synthase Gene Expression in Arabidopsis
BACKGROUND: RNA-dependent RNA polymerases (RDRs) function in anti-viral silencing in Arabidopsis thaliana and other plants. Salicylic acid (SA), an important defensive signal, increases RDR1 gene expression, suggesting that RDR1 contributes to SA-induced virus resistance. In Nicotiana attenuata RDR1...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Public Library of Science
2013
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3684572/ https://www.ncbi.nlm.nih.gov/pubmed/23799112 http://dx.doi.org/10.1371/journal.pone.0066530 |
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author | Hunter, Lydia J. R. Westwood, Jack H. Heath, Geraldine Macaulay, Keith Smith, Alison G. MacFarlane, Stuart A. Palukaitis, Peter Carr, John P. |
author_facet | Hunter, Lydia J. R. Westwood, Jack H. Heath, Geraldine Macaulay, Keith Smith, Alison G. MacFarlane, Stuart A. Palukaitis, Peter Carr, John P. |
author_sort | Hunter, Lydia J. R. |
collection | PubMed |
description | BACKGROUND: RNA-dependent RNA polymerases (RDRs) function in anti-viral silencing in Arabidopsis thaliana and other plants. Salicylic acid (SA), an important defensive signal, increases RDR1 gene expression, suggesting that RDR1 contributes to SA-induced virus resistance. In Nicotiana attenuata RDR1 also regulates plant-insect interactions and is induced by another important signal, jasmonic acid (JA). Despite its importance in defense RDR1 regulation has not been investigated in detail. METHODOLOGY/PRINCIPAL FINDINGS: In Arabidopsis, SA-induced RDR1 expression was dependent on ‘NON-EXPRESSER OF PATHOGENESIS-RELATED GENES 1’, indicating regulation involves the same mechanism controlling many other SA- defense-related genes, including pathogenesis-related 1 (PR1). Isochorismate synthase 1 (ICS1) is required for SA biosynthesis. In defensive signal transduction RDR1 lies downstream of ICS1. However, supplying exogenous SA to ics1-mutant plants did not induce RDR1 or PR1 expression to the same extent as seen in wild type plants. Analysing ICS1 gene expression using transgenic plants expressing ICS1 promoter:reporter gene (β-glucuronidase) constructs and by measuring steady-state ICS1 transcript levels showed that SA positively regulates ICS1. In contrast, ICS2, which is expressed at lower levels than ICS1, is unaffected by SA. The wound-response hormone JA affects expression of Arabidopsis RDR1 but jasmonate-induced expression is independent of CORONATINE-INSENSITIVE 1, which conditions expression of many other JA-responsive genes. Transiently increased RDR1 expression following tobacco mosaic virus inoculation was due to wounding and was not a direct effect of infection. RDR1 gene expression was induced by ethylene and by abscisic acid (an important regulator of drought resistance). However, rdr1-mutant plants showed normal responses to drought. CONCLUSIONS/SIGNIFICANCE: RDR1 is regulated by a much broader range of phytohormones than previously thought, indicating that it plays roles beyond those already suggested in virus resistance and plant-insect interactions. SA positively regulates ICS1. |
format | Online Article Text |
id | pubmed-3684572 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2013 |
publisher | Public Library of Science |
record_format | MEDLINE/PubMed |
spelling | pubmed-36845722013-06-24 Regulation of RNA-Dependent RNA Polymerase 1 and Isochorismate Synthase Gene Expression in Arabidopsis Hunter, Lydia J. R. Westwood, Jack H. Heath, Geraldine Macaulay, Keith Smith, Alison G. MacFarlane, Stuart A. Palukaitis, Peter Carr, John P. PLoS One Research Article BACKGROUND: RNA-dependent RNA polymerases (RDRs) function in anti-viral silencing in Arabidopsis thaliana and other plants. Salicylic acid (SA), an important defensive signal, increases RDR1 gene expression, suggesting that RDR1 contributes to SA-induced virus resistance. In Nicotiana attenuata RDR1 also regulates plant-insect interactions and is induced by another important signal, jasmonic acid (JA). Despite its importance in defense RDR1 regulation has not been investigated in detail. METHODOLOGY/PRINCIPAL FINDINGS: In Arabidopsis, SA-induced RDR1 expression was dependent on ‘NON-EXPRESSER OF PATHOGENESIS-RELATED GENES 1’, indicating regulation involves the same mechanism controlling many other SA- defense-related genes, including pathogenesis-related 1 (PR1). Isochorismate synthase 1 (ICS1) is required for SA biosynthesis. In defensive signal transduction RDR1 lies downstream of ICS1. However, supplying exogenous SA to ics1-mutant plants did not induce RDR1 or PR1 expression to the same extent as seen in wild type plants. Analysing ICS1 gene expression using transgenic plants expressing ICS1 promoter:reporter gene (β-glucuronidase) constructs and by measuring steady-state ICS1 transcript levels showed that SA positively regulates ICS1. In contrast, ICS2, which is expressed at lower levels than ICS1, is unaffected by SA. The wound-response hormone JA affects expression of Arabidopsis RDR1 but jasmonate-induced expression is independent of CORONATINE-INSENSITIVE 1, which conditions expression of many other JA-responsive genes. Transiently increased RDR1 expression following tobacco mosaic virus inoculation was due to wounding and was not a direct effect of infection. RDR1 gene expression was induced by ethylene and by abscisic acid (an important regulator of drought resistance). However, rdr1-mutant plants showed normal responses to drought. CONCLUSIONS/SIGNIFICANCE: RDR1 is regulated by a much broader range of phytohormones than previously thought, indicating that it plays roles beyond those already suggested in virus resistance and plant-insect interactions. SA positively regulates ICS1. Public Library of Science 2013-06-17 /pmc/articles/PMC3684572/ /pubmed/23799112 http://dx.doi.org/10.1371/journal.pone.0066530 Text en © 2013 Hunter et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited. |
spellingShingle | Research Article Hunter, Lydia J. R. Westwood, Jack H. Heath, Geraldine Macaulay, Keith Smith, Alison G. MacFarlane, Stuart A. Palukaitis, Peter Carr, John P. Regulation of RNA-Dependent RNA Polymerase 1 and Isochorismate Synthase Gene Expression in Arabidopsis |
title | Regulation of RNA-Dependent RNA Polymerase 1 and Isochorismate Synthase Gene Expression in Arabidopsis
|
title_full | Regulation of RNA-Dependent RNA Polymerase 1 and Isochorismate Synthase Gene Expression in Arabidopsis
|
title_fullStr | Regulation of RNA-Dependent RNA Polymerase 1 and Isochorismate Synthase Gene Expression in Arabidopsis
|
title_full_unstemmed | Regulation of RNA-Dependent RNA Polymerase 1 and Isochorismate Synthase Gene Expression in Arabidopsis
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title_short | Regulation of RNA-Dependent RNA Polymerase 1 and Isochorismate Synthase Gene Expression in Arabidopsis
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title_sort | regulation of rna-dependent rna polymerase 1 and isochorismate synthase gene expression in arabidopsis |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3684572/ https://www.ncbi.nlm.nih.gov/pubmed/23799112 http://dx.doi.org/10.1371/journal.pone.0066530 |
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