title: Overexpression of farnesyl diphosphate synthase in Arabidopsis mitochondria triggers light-dependent lesion formation and alters cytokinin homeostasis.
abstract: To investigate the role of mitochondrial farnesyl diphosphate synthase (FPS) in plant isoprenoid biosynthesis we characterized transgenic Arabidopsis thaliana plants overexpressing FPS1L isoform. This overexpressed protein was properly targeted to mitochondria yielding a mature and active form of the enzyme of 40 kDa. Leaves from transgenic plants grown under continuous light exhibited symptoms of chlorosis and cell death correlating to H(2)O(2) accumulation, and leaves detached from the same plants displayed accelerated senescence. Overexpression of FPS in mitochondria also led to altered leaf cytokinin profile, with a reduction in the contents of physiologically active trans-zeatin- and isopentenyladenine-type cytokinins and their corresponding riboside monophosphates as well as enhanced levels of cis-zeatin 7-glucoside and storage cytokinin O-glucosides. Overexpression of 3-hydroxy-3-methylglutaryl coenzyme A reductase did not prevent chlorosis in plants overexpressing FPS1L, but did rescue accelerated senescence of detached leaves and restored wild-type levels of cytokinins. We propose that the overexpression of FPS1L leads to an enhanced uptake and metabolism of mevalonic acid-derived isopentenyl diphosphate and/or dimethylallyl diphosphate by mitochondria, thereby altering cytokinin homeostasis and causing a mitochondrial dysfunction that renders plants more sensitive to the oxidative stress induced by continuous light.
authors.affiliation: Departament de Bioquímica i Biologia Molecular, Facultat de Farmàcia, Universitat de Barcelona, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Manzano
authors.forename: Antoni
authors.initials: A
authors.lastname: Busquets
authors.forename: Marta
authors.initials: M
authors.lastname: Closa
authors.forename: Klára
authors.initials: K
authors.lastname: Hoyerová
authors.forename: Hubert
authors.initials: H
authors.lastname: Schaller
authors.forename: Miroslav
authors.initials: M
authors.lastname: Kamínek
authors.forename: Montserrat
authors.initials: M
authors.lastname: Arró
authors.forename: Albert
authors.initials: A
authors.lastname: Ferrer
mesh_terms: D000214:Acyl Coenzyme A / Q000378:metabolism; D017360:Arabidopsis / Q000033:anatomy & histology / Q000201:enzymology* / Q000235:genetics; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016922:Cellular Senescence; D003583:Cytokinins / Q000378:metabolism*; D051228:Geranyltranstransferase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006706:Homeostasis; D008027:Light; D008928:Mitochondria / Q000201:enzymology* / Q000648:ultrastructure; D018384:Oxidative Stress; D010641:Phenotype; D018515:Plant Leaves / Q000033:anatomy & histology / Q000201:enzymology / Q000254:growth & development; D030821:Plants, Genetically Modified / Q000201:enzymology* / Q000648:ultrastructure; D017434:Protein Structure, Tertiary; D021381:Protein Transport
chemical_list: D000214:Acyl Coenzyme A; D029681:Arabidopsis Proteins; D003583:Cytokinins; C008047:3-hydroxy-3-methylglutaryl-coenzyme A; D051228:Geranyltranstransferase