| Title: | Stress- and pathway-specific impacts of impaired jasmonoyl-isoleucine (JA-Ile) catabolism on defense signalling and biotic stress resistance |
| Author(s): | Marquis V; Smirnova E; Poirier L; Zumsteg J; Schweizer F; Reymond P; Heitz T; |
| Address: | "Institut de Biologie Moleculaire des Plantes (IBMP) du CNRS, Universite de Strasbourg, Strasbourg, France. Department of Plant Molecular Biology, University of Lausanne, Lausanne, Switzerland" |
| ISSN/ISBN: | 1365-3040 (Electronic) 0140-7791 (Linking) |
| Abstract: | "Jasmonate synthesis and signalling are essential for plant defense upregulation upon herbivore or microbial attacks. Stress-induced accumulation of jasmonoyl-isoleucine (JA-Ile), the bioactive hormonal form triggering transcriptional changes, is dynamic and transient because of the existence of potent removal mechanisms. Two JA-Ile turnover pathways operate in Arabidopsis, consisting in cytochrome P450 (CYP94)-mediated oxidation and deconjugation by the amidohydrolases IAR3/ILL6. Understanding their impacts was previously blurred by gene redundancy and compensation mechanisms. Here we address the consequences of blocking these pathways on jasmonate homeostasis and defenses in double-2ah, triple-3cyp mutants, and a quintuple-5ko line deficient in all known JA-Ile-degrading activities. These lines reacted differently to either mechanical wounding/insect attack or fungal infection. Both pathways contributed additively to JA-Ile removal upon wounding, but their impairement had opposite impacts on insect larvae feeding. By contrast, only the ah pathway was essential for JA-Ile turnover upon infection by Botrytis, yet only 3cyp was more fungus-resistant. Despite building-up extreme JA-Ile levels, 5ko displayed near-wild-type resistance in both bioassays. Molecular analysis indicated that restrained JA-Ile catabolism resulted in enhanced defense/resistance only when genes encoding negative regulators were not simultaneously overstimulated. This occurred in discrete stress- and pathway-specific combinations, providing a framework for future defense-enhancing strategies" |
| Keywords: | "Arabidopsis/genetics/*immunology/microbiology/*physiology Botrytis/physiology Cyclopentanes/*metabolism Feedback, Physiological Gene Expression Regulation, Plant Genes, Plant Genotype Homeostasis Isoleucine/*analogs & derivatives/metabolism Mutation/genet;" |
| Notes: | "MedlineMarquis, Valentin Smirnova, Ekaterina Poirier, Laure Zumsteg, Julie Schweizer, Fabian Reymond, Philippe Heitz, Thierry eng 31003A_169278/SNSF_/Swiss National Science Foundation/Switzerland Research Support, Non-U.S. Gov't 2020/03/13 Plant Cell Environ. 2020 Jun; 43(6):1558-1570. doi: 10.1111/pce.13753. Epub 2020 Mar 25" |
