Differential distribution of the lipoxygenase pathway enzymes within potato chloroplasts
| Autor: | Jose J. Sánchez-Serrano, Maite Sanmartín, Carlos Sanz, Pedro Jiménez, Manuel Paneque, Theodora Farmaki, José León, Guy Vancanneyt |
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| Rok vydání: | 2006 |
| Předmět: |
Chloroplasts
Physiology Blotting Western Green Fluorescent Proteins Lipoxygenase Molecular Sequence Data Plant Science Biology Cell Fractionation Thylakoids chemistry.chemical_compound Cytochrome P-450 Enzyme System Aldehyde-Lyases Plant Proteins Solanum tuberosum chemistry.chemical_classification Microscopy Confocal ATP synthase Jasmonic acid Allene-oxide cyclase food and beverages Subcellular localization Intramolecular Oxidoreductases Chloroplast Enzyme Biochemistry chemistry Thylakoid biology.protein |
| Zdroj: | Journal of Experimental Botany. 58:555-568 |
| ISSN: | 1460-2431 0022-0957 |
| Popis: | The lipoxygenase pathway is responsible for the production of oxylipins, which are important compounds for plant defence responses. Jasmonic acid, the final product of the allene oxide synthase/allene oxide cyclase branch of the pathway, regulates wound-induced gene expression. In contrast, C6 aliphatic aldehydes produced via an alternative branch catalysed by hydroperoxide lyase, are themselves toxic to pests and pathogens. Current evidence on the subcellular localization of the lipoxygenase pathway is conflicting, and the regulation of metabolic channelling between the two branches of the pathway is largely unknown. It is shown here that while a 13-lipoxygenase (LOX H3), allene oxide synthase and allene oxide cyclase proteins accumulate upon wounding in potato, a second 13-lipoxygenase (LOX H1) and hydroperoxide lyase are present at constant levels in both non-wounded and wounded tissues. Wound-induced accumulation of the jasmonic acid biosynthetic enzymes may thus commit the lipoxygenase pathway to jasmonic acid production in damaged plants. It is shown that all enzymes of the lipoxygenase pathway differentially localize within chloroplasts, and are largely found associated to thylakoid membranes. This differential localization is consistently observed using confocal microscopy of GFP-tagged proteins, chloroplast fractionation, and western blotting, and immunodetection by electron microscopy. While LOX H1 and LOX H3 are localized both in stroma and thylakoids, both allene oxide synthase and hydroperoxide lyase protein localize almost exclusively to thylakoids and are strongly bound to membranes. Allene oxide cyclase is weakly associated with the thylakoid membrane and is also detected in the stroma. Moreover, allene oxide synthase and hydroperoxide lyase are differentially distributed in thylakoids, with hydroperoxide lyase localized almost exclusively to the stromal part, thus closely resembling the localization pattern of LOX H1. It is suggested that, in addition to their differential expression pattern, this segregation underlies the regulation of metabolic fluxes through the alternative branches of the lipoxygenase pathway. |
| Databáze: | OpenAIRE |
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