1. Functional Characterization of CYP94-Genes and Identification of a Novel Jasmonate Catabolite in Flowers
- Author
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Bruckhoff, Viktoria, Haroth, Sven, Feussner, Kirstin, König, Stefanie, Brodhun, Florian, and Feussner, Ivo
- Subjects
Leaves ,Ionization ,Flowers ,Flowering plants ,Arabidopsis thaliana ,Metabolites ,Jasmonic acid ,Oxidation ,Arabidopsis Thaliana ,Arabidopsis ,lcsh:Medicine ,Cyclopentanes ,Plant Science ,Brassica ,Genes, Plant ,Research and Analysis Methods ,Biochemistry ,Model Organisms ,Cytochrome P-450 Enzyme System ,Plant and Algal Models ,Homeostasis ,Oxylipins ,Plant Hormones ,lcsh:Science ,Flowering Plants ,Arabidopsis Proteins ,Plant Biochemistry ,Plant Anatomy ,lcsh:R ,Organisms ,Chemical Reactions ,Biology and Life Sciences ,Plants ,Hormones ,Chemistry ,Metabolism ,Mutation ,Jasmonic Acid ,Physical Sciences ,lcsh:Q ,Gene Deletion ,Signal Transduction ,Research Article - Abstract
Over the past decades much research focused on the biosynthesis of the plant hormone jasmonyl-isoleucine (JA-Ile). While many details about its biosynthetic pathway as well about its physiological function are established nowadays, knowledge about its catabolic fate is still scarce. Only recently, the hormonal inactivation mechanisms became a stronger research focus. Two major pathways have been proposed to inactivate JA-Ile: i) The cleavage of the jasmonyl-residue from the isoleucine moiety, a reaction that is catalyzed by specific amido-hydrolases, or ii), the sequential oxidation of the ω-end of the pentenyl side-chain. This reaction is catalyzed by specific members of the cytochrome P450 (CYP) subfamily CYP94: CYP94B1, CYP94B3 and CYP94C1. In the present study, we further investigated the oxidative fate of JA-Ile by expanding the analysis on Arabidopsis thaliana mutants, lacking only one (cyp94b1, cyp94b2, cyp94b3, cyp94c1), two (cyp94b1xcyp94b2, cyp94b1xcyp94b3, cyp94b2xcyp94b3), three (cyp94b1xcyp94b2xcyp94b3) or even four (cyp94b1xcyp94b2xcyp94b3xcyp94c1) CYP94 functionalities. The results obtained in the present study show that CYP94B1, CYP94B2, CYP94B3 and CYP94C1 are responsible for catalyzing the sequential ω-oxidation of JA-Ile in a semi-redundant manner. While CYP94B-enzymes preferentially hydroxylate JA-Ile to 12-hydroxy-JA-Ile, CYP94C1 catalyzes primarily the subsequent oxidation, yielding 12-carboxy-JA-Ile. In addition, data obtained from investigating the triple and quadruple mutants let us hypothesize that a direct oxidation of unconjugated JA to 12-hydroxy-JA is possible in planta. Using a non-targeted metabolite fingerprinting analysis, we identified unconjugated 12-carboxy-JA as novel jasmonate derivative in floral tissues. Using the same approach, we could show that deletion of CYP94-genes might not only affect JA-homeostasis but also other signaling pathways. Deletion of CYP94B1, for example, led to accumulation of metabolites that may be characteristic for plant stress responses like systemic acquired resistance. Evaluation of the in vivo function of the different CYP94-enzymes on the JA-sensitivity demonstrated that particularly CYP94B-enzymes might play an essential role for JA-response, whereas CYP94C1 might only be of minor importance. Open-Access-Publikationsfonds 2016 peerReviewed
- Published
- 2016