Characterization of Arabidopsismur3mutations that result in constitutive activation of defence in petioles, but not leaves
| Autor: | Florence Jay, Rita Lei, Jonathan D. G. Jones, Charles A. Brearley, Xuemei Li, Wolf-Dieter Reiter, Georgina Fabro, Jennifer D. Tedman-Jones |
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| Rok vydání: | 2008 |
| Předmět: |
Positional cloning
Transgene Mutant Arabidopsis Plant Science Biology Genes Plant Gene Knockout Techniques Cell Wall Gene Expression Regulation Plant Genes Reporter Genetics Hyaloperonospora parasitica Point Mutation Arabidopsis thaliana Luciferase Cloning Molecular Promoter Regions Genetic Intramolecular Transferases Alleles Arabidopsis Proteins Reverse Transcriptase Polymerase Chain Reaction Genetic Complementation Test Chromosome Mapping Cell Biology Galactosyltransferases Plants Genetically Modified biology.organism_classification Actins Immunity Innate Cell biology Plant Leaves Transformation (genetics) Biochemistry Mutagenesis RNA Plant Isochorismate synthase biology.protein Reactive Oxygen Species Salicylic Acid |
| Zdroj: | The Plant Journal. 56:691-703 |
| ISSN: | 1365-313X 0960-7412 |
| DOI: | 10.1111/j.1365-313x.2008.03636.x |
| Popis: | A screen was established for mutants in which the plant defence response is de-repressed. The pathogen-inducible isochorismate synthase (ICS1) promoter was fused to firefly luciferase (luc) and a homozygous transgenic line generated in which the ICS1:luc fusion is co-regulated with ICS1. This line was mutagenized and M(2) seedlings screened for constitutive ICS1:luc expression (cie). The cie mutants fall into distinct phenotypic classes based on tissue-specific localization of luciferase activity. One mutant, cie1, that shows constitutive luciferase activity specifically in petioles, was chosen for further analysis. In addition to ICS1, PR and other defence-related genes are constitutively expressed in cie1 plants. The cie1 mutant is also characterized by an increased production of conjugated salicylic acid and reactive oxygen intermediates, as well as spontaneous lesion formation, all confined to petiole tissue. Significantly, defences activated in cie1 are sufficient to prevent infection by a virulent isolate of Hyaloperonospora parasitica, and this enhanced resistance response protects petiole tissue alone. Furthermore, cie1-mediated resistance, along with PR gene expression, is abolished in a sid2-1 mutant background, consistent with a requirement for salicylic acid. A positional cloning approach was used to identify cie1, which carries two point mutations in a gene required for cell wall biosynthesis and actin organization, MUR3. A mur3 knockout mutant also resists infection by H. parasitica in its petioles and this phenotype is complemented by transformation with wild-type MUR3. We propose that perturbed cell wall biosynthesis may activate plant defence and provide a rationale for the cie1 and the mur3 knockout phenotypes. |
| Databáze: | OpenAIRE |
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