title: Chloroplastic phosphoadenosine phosphosulfate metabolism regulates basal levels of the prohormone jasmonic acid in Arabidopsis leaves.
abstract: Levels of the enzymes that produce wound response mediators have to be controlled tightly in unwounded tissues. The Arabidopsis (Arabidopsis thaliana) fatty acid oxygenation up-regulated8 (fou8) mutant catalyzes high rates of alpha -linolenic acid oxygenation and has higher than wild-type levels of the alpha -linolenic acid-derived wound response mediator jasmonic acid (JA) in undamaged leaves. fou8 produces a null allele in the gene SAL1 (also known as FIERY1 or FRY1). Overexpression of the wild-type gene product had the opposite effect of the null allele, suggesting a regulatory role of SAL1 acting in JA synthesis. The biochemical phenotypes in fou8 were complemented when the yeast (Saccharomyces cerevisiae) sulfur metabolism 3'(2'), 5'-bisphosphate nucleotidase MET22 was targeted to chloroplasts in fou8. The data are consistent with a role of SAL1 in the chloroplast-localized dephosphorylation of 3'-phospho-5'-adenosine phosphosulfate to 5'-adenosine phosphosulfate or in a closely related reaction (e.g. 3',5'-bisphosphate dephosphorylation). Furthermore, the fou8 phenotype was genetically suppressed in a triple mutant (fou8 apk1 apk2) affecting chloroplastic 3'-phospho-5'-adenosine phosphosulfate synthesis. These results show that a nucleotide component of the sulfur futile cycle regulates early steps of JA production and basal JA levels.
authors.affiliation: Department of Plant Molecular Biology, University of Lausanne, Biophore, CH-1015 Lausanne, Switzerland.
authors.forename: Víctor M
authors.initials: VM
authors.lastname: Rodríguez
authors.forename: Aurore
authors.initials: A
authors.lastname: Chételat
authors.forename: Paul
authors.initials: P
authors.lastname: Majcherczyk
authors.forename: Edward E
authors.initials: EE
authors.lastname: Farmer
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism; D002736:Chloroplasts / Q000378:metabolism*; D003517:Cyclopentanes / Q000378:metabolism*; D018744:DNA, Plant / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D009154:Mutation; D054883:Oxylipins / Q000378:metabolism*; D010724:Phosphoadenosine Phosphosulfate / Q000378:metabolism*; D010744:Phosphoric Monoester Hydrolases / Q000235:genetics / Q000378:metabolism*; D010937:Plant Growth Regulators / Q000378:metabolism; D018515:Plant Leaves / Q000378:metabolism*; D030821:Plants, Genetically Modified / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D003517:Cyclopentanes; D018744:DNA, Plant; D054883:Oxylipins; D010937:Plant Growth Regulators; D010724:Phosphoadenosine Phosphosulfate; C011006:jasmonic acid; D010744:Phosphoric Monoester Hydrolases; C053087:inositol-1,4-bisphosphate 1-phosphatase